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authorLukas Oesch <lukas.oesch@ost.ch>2026-06-10 10:40:46 +0200
committerLukas Oesch <lukas.oesch@ost.ch>2026-06-10 10:40:46 +0200
commit33abd5cf264cb9e34121082105b0bc17b3cf7a36 (patch)
tree36b15d53fea04f4f9d9af817100f7ad013bd9b5c /kernel/src
parentd01caf1c4aef3c89c68b9d1cc9fe56445f0860b5 (diff)
parent7e27130c342b7299a1d2188a7192a7f17b5ac2ad (diff)
downloadkernel-33abd5cf264cb9e34121082105b0bc17b3cf7a36.tar.xz
kernel-33abd5cf264cb9e34121082105b0bc17b3cf7a36.zip
Merge branch 'develop-BA-FS26' into 'develop'HEADdevelop
Merge of BA-FS26 branch into develop See merge request teachos/kernel!49
Diffstat (limited to 'kernel/src')
-rw-r--r--kernel/src/acpi/manager.cpp98
-rw-r--r--kernel/src/devices/block_device.cpp42
-rw-r--r--kernel/src/devices/block_device.tests.cpp46
-rw-r--r--kernel/src/devices/block_device_utils.cpp106
-rw-r--r--kernel/src/devices/block_device_utils.tests.cpp219
-rw-r--r--kernel/src/devices/root_bus.cpp12
-rw-r--r--kernel/src/devices/storage/controller.cpp44
-rw-r--r--kernel/src/devices/storage/management.cpp95
-rw-r--r--kernel/src/devices/storage/ram_disk/controller.cpp27
-rw-r--r--kernel/src/devices/storage/ram_disk/device.cpp71
-rw-r--r--kernel/src/devices/storage/ram_disk/device.tests.cpp116
-rw-r--r--kernel/src/filesystem/dentry.cpp95
-rw-r--r--kernel/src/filesystem/dentry.tests.cpp150
-rw-r--r--kernel/src/filesystem/devfs/filesystem.cpp81
-rw-r--r--kernel/src/filesystem/devfs/filesystem.tests.cpp72
-rw-r--r--kernel/src/filesystem/devfs/inode.cpp21
-rw-r--r--kernel/src/filesystem/devfs/inode.tests.cpp55
-rw-r--r--kernel/src/filesystem/device_inode.cpp57
-rw-r--r--kernel/src/filesystem/device_inode.tests.cpp109
-rw-r--r--kernel/src/filesystem/ext2/filesystem.cpp247
-rw-r--r--kernel/src/filesystem/ext2/filesystem.tests.cpp139
-rw-r--r--kernel/src/filesystem/ext2/inode.cpp111
-rw-r--r--kernel/src/filesystem/ext2/inode.tests.cpp376
-rw-r--r--kernel/src/filesystem/filesystem.cpp60
-rw-r--r--kernel/src/filesystem/inode.cpp24
-rw-r--r--kernel/src/filesystem/mount.cpp90
-rw-r--r--kernel/src/filesystem/mount.tests.cpp94
-rw-r--r--kernel/src/filesystem/mount_table.cpp79
-rw-r--r--kernel/src/filesystem/mount_table.tests.cpp184
-rw-r--r--kernel/src/filesystem/open_file_descriptor.cpp46
-rw-r--r--kernel/src/filesystem/open_file_descriptor.tests.cpp113
-rw-r--r--kernel/src/filesystem/open_file_table.cpp87
-rw-r--r--kernel/src/filesystem/open_file_table.tests.cpp106
-rw-r--r--kernel/src/filesystem/path.tests.cpp69
-rw-r--r--kernel/src/filesystem/rootfs/filesystem.cpp47
-rw-r--r--kernel/src/filesystem/rootfs/filesystem.tests.cpp38
-rw-r--r--kernel/src/filesystem/rootfs/inode.cpp23
-rw-r--r--kernel/src/filesystem/rootfs/inode.tests.cpp37
-rw-r--r--kernel/src/filesystem/type_registry.cpp72
-rw-r--r--kernel/src/filesystem/type_registry.tests.cpp77
-rw-r--r--kernel/src/filesystem/vfs.cpp299
-rw-r--r--kernel/src/filesystem/vfs.tests.cpp568
-rw-r--r--kernel/src/main.cpp142
-rw-r--r--kernel/src/memory.cpp15
-rw-r--r--kernel/src/memory/bitmap_allocator.cpp24
-rw-r--r--kernel/src/memory/bitmap_allocator.tests.cpp288
-rw-r--r--kernel/src/memory/block_list_allocator.cpp36
-rw-r--r--kernel/src/memory/block_list_allocator.tests.cpp85
-rw-r--r--kernel/src/memory/mmio_allocator.cpp111
-rw-r--r--kernel/src/memory/operators.cpp21
-rw-r--r--kernel/src/test_support/devices/block_device.cpp61
-rw-r--r--kernel/src/test_support/devices/character_device.cpp19
-rw-r--r--kernel/src/test_support/filesystem/ext2.cpp68
-rw-r--r--kernel/src/test_support/filesystem/filesystem.cpp17
-rw-r--r--kernel/src/test_support/filesystem/inode.cpp23
-rw-r--r--kernel/src/test_support/filesystem/storage_boot_module_fixture.cpp139
-rw-r--r--kernel/src/test_support/filesystem/storage_boot_module_vfs_fixture.cpp31
l---------kernel/src/test_support/filesystem/test_assets/README.md1
-rw-r--r--kernel/src/test_support/filesystem/test_assets/ext2_1KB_fs.img3
-rw-r--r--kernel/src/test_support/filesystem/test_assets/ext2_2KB_fs.img3
-rw-r--r--kernel/src/test_support/filesystem/test_assets/ext2_4KB_fs.img3
-rw-r--r--kernel/src/test_support/kapi/cio.cpp54
-rw-r--r--kernel/src/test_support/kapi/cpu.cpp52
-rw-r--r--kernel/src/test_support/kapi/interrupts.cpp11
-rw-r--r--kernel/src/test_support/kapi/memory.cpp74
-rw-r--r--kernel/src/test_support/log_buffer.cpp33
-rw-r--r--kernel/src/test_support/output_device.cpp28
-rw-r--r--kernel/src/test_support/page_mapper.cpp70
-rw-r--r--kernel/src/test_support/simulated_memory.cpp106
-rw-r--r--kernel/src/test_support/state_reset_listener.cpp48
70 files changed, 6021 insertions, 47 deletions
diff --git a/kernel/src/acpi/manager.cpp b/kernel/src/acpi/manager.cpp
new file mode 100644
index 0000000..bb895fd
--- /dev/null
+++ b/kernel/src/acpi/manager.cpp
@@ -0,0 +1,98 @@
+#include <kernel/acpi/manager.hpp>
+
+#include <kapi/memory.hpp>
+#include <kapi/system.hpp>
+
+#include <acpi/acpi.hpp>
+
+#include <kstd/memory>
+#include <kstd/print>
+
+#include <algorithm>
+#include <cstddef>
+#include <cstdint>
+#include <ranges>
+#include <string_view>
+
+namespace kernel::acpi
+{
+
+ manager::manager(::acpi::rsdp const & sdp)
+ : m_sdp{&sdp}
+ {
+ if (!m_sdp->validate())
+ {
+ kapi::system::panic("[OS:ACPI] Invalid RSDP signature!");
+ }
+
+ m_extended = m_sdp->revision() >= 2;
+
+ if (m_extended)
+ {
+ if (!static_cast<::acpi::xsdp const *>(m_sdp)->validate())
+ {
+ kapi::system::panic("[OS:ACPI] Invalid XSDP signature!");
+ }
+ }
+ else
+ {
+ if (!m_sdp->validate())
+ {
+ kapi::system::panic("[OS:ACPI] Invalid RSDP checksum!");
+ }
+ }
+
+ auto physical_address = kapi::memory::physical_address{m_sdp->table_address()};
+ auto linear_address = kapi::memory::hhdm_to_linear(physical_address);
+ m_rsdt = static_cast<::acpi::table_header const *>(linear_address);
+ }
+
+ auto manager::load_tables() -> bool
+ {
+ if (!::acpi::validate_checksum({reinterpret_cast<std::byte const *>(m_rsdt), m_rsdt->length().value}))
+ {
+ kapi::system::panic("[OS:ACPI] Invalid RSDT checksum!");
+ }
+
+ auto check_and_register_table = [&](auto table_address) -> void {
+ auto physical_table_address = kapi::memory::physical_address{reinterpret_cast<std::uintptr_t>(table_address)};
+ auto mapped_table = kapi::memory::hhdm_to_linear(physical_table_address);
+ auto table = static_cast<::acpi::table_header const *>(mapped_table);
+
+ if (!::acpi::validate_checksum({static_cast<std::byte const *>(mapped_table), table->length().value}))
+ {
+ kstd::println(kstd::print_sink::stderr, "[OS:ACPI] Invalid table checksum!");
+ }
+ else
+ {
+ kstd::println("[OS:ACPI] Found '{}' ACPI table", table->signature());
+ m_tables.emplace(table->signature(), table);
+ }
+ };
+
+ if (m_extended)
+ {
+ auto xsdt = static_cast<::acpi::xsdt const *>(m_rsdt);
+ std::ranges::for_each(*xsdt | std::views::transform([](auto const & entry) { return entry.address(); }),
+ check_and_register_table);
+ }
+ else
+ {
+ auto rsdt = static_cast<::acpi::rsdt const *>(m_rsdt);
+ std::ranges::for_each(*rsdt | std::views::transform([](auto const & entry) { return entry.address(); }),
+ check_and_register_table);
+ }
+
+ return !m_tables.empty();
+ }
+
+ auto manager::get_table(std::string_view signature) -> kstd::observer_ptr<::acpi::table_header const>
+ {
+ if (m_tables.contains(signature))
+ {
+ return kstd::make_observer(m_tables.at(signature));
+ }
+ return nullptr;
+ }
+
+} // namespace kernel::acpi
diff --git a/kernel/src/devices/block_device.cpp b/kernel/src/devices/block_device.cpp
new file mode 100644
index 0000000..13d73ac
--- /dev/null
+++ b/kernel/src/devices/block_device.cpp
@@ -0,0 +1,42 @@
+#include <kernel/devices/block_device.hpp>
+
+#include <kapi/devices/device.hpp>
+#include <kapi/system.hpp>
+
+#include <kstd/string>
+
+#include <cstddef>
+
+namespace kernel::devices
+{
+ block_device::block_device(size_t major, size_t minor, kstd::string const & name, size_t block_size)
+ : kapi::devices::device(major, minor, name)
+ , m_block_size(block_size)
+ {
+ if (m_block_size == 0)
+ {
+ kapi::system::panic("[DEVICES] block_device constructed with zero block size.");
+ }
+ }
+
+ auto block_device::calculate_transfer(size_t block_index) const -> transfer_info
+ {
+ size_t const offset = block_index * m_block_size;
+ size_t const limit = size();
+
+ size_t const available = (offset < limit) ? (limit - offset) : 0;
+ size_t const to_transfer = (available < m_block_size) ? available : m_block_size;
+
+ return {offset, to_transfer, m_block_size - to_transfer};
+ }
+
+ auto block_device::block_size() const -> size_t
+ {
+ return m_block_size;
+ }
+
+ auto block_device::capacity() const -> size_t
+ {
+ return size();
+ }
+} // namespace kernel::devices \ No newline at end of file
diff --git a/kernel/src/devices/block_device.tests.cpp b/kernel/src/devices/block_device.tests.cpp
new file mode 100644
index 0000000..a2ddd2b
--- /dev/null
+++ b/kernel/src/devices/block_device.tests.cpp
@@ -0,0 +1,46 @@
+#include <kernel/test_support/devices/block_device.hpp>
+
+#include <kernel/test_support/cpu.hpp>
+
+#include <kstd/memory>
+#include <kstd/print>
+#include <kstd/string>
+#include <kstd/vector>
+
+#include <catch2/catch_test_macros.hpp>
+
+#include <cstddef>
+
+SCENARIO("Block device construction", "[devices][block_device]")
+{
+ GIVEN("parameters for a block device")
+ {
+ size_t major = 1;
+ size_t minor = 0;
+ kstd::string name = "test_block_device";
+ size_t block_size = 512;
+
+ WHEN("constructing a block device")
+ {
+ auto device =
+ kstd::make_shared<kernel::tests::devices::block_device>(major, minor, name, block_size, 3 * block_size);
+
+ THEN("the block device has the correct properties")
+ {
+ REQUIRE(device->major() == major);
+ REQUIRE(device->minor() == minor);
+ REQUIRE(device->name() == name);
+ REQUIRE(device->block_size() == block_size);
+ REQUIRE(device->capacity() == 3 * 512);
+ }
+ }
+
+ WHEN("constructing a block device with zero block size")
+ {
+ THEN("the constructor panics")
+ {
+ REQUIRE_THROWS_AS((kernel::tests::devices::block_device(major, minor, name, 0)), kernel::tests::cpu::halt);
+ }
+ }
+ }
+}
diff --git a/kernel/src/devices/block_device_utils.cpp b/kernel/src/devices/block_device_utils.cpp
new file mode 100644
index 0000000..18d1e9d
--- /dev/null
+++ b/kernel/src/devices/block_device_utils.cpp
@@ -0,0 +1,106 @@
+#include <kernel/devices/block_device_utils.hpp>
+
+#include <kernel/devices/block_device.hpp>
+
+#include <kapi/devices/device.hpp>
+#include <kapi/system.hpp>
+
+#include <kstd/cstring>
+#include <kstd/memory>
+#include <kstd/vector>
+
+#include <algorithm>
+#include <cstddef>
+
+namespace kernel::devices::block_device_utils
+{
+
+ using block_op = void (*)(size_t idx, size_t off, size_t len, size_t done, devices::block_device * device,
+ std::byte * scratch, void * buffer);
+
+ auto process_blocks(kstd::shared_ptr<kapi::devices::device> const & device, size_t offset, size_t size, void * buffer,
+ block_op op) -> size_t
+ {
+ if (buffer == nullptr)
+ {
+ kapi::system::panic("[FILESYSTEM] device_file::process_blocks called with null buffer.");
+ }
+
+ if (size == 0)
+ {
+ return 0;
+ }
+
+ if (!device->is_block_device())
+ {
+ kapi::system::panic("[FILESYSTEM] device_file: expected block_device.");
+ }
+
+ auto * block_dev = static_cast<devices::block_device *>(device.get());
+
+ size_t const block_size = block_dev->block_size();
+ size_t const capacity = block_dev->capacity();
+
+ if (offset >= capacity)
+ {
+ return 0;
+ }
+ size_t const total_to_process = std::min(size, capacity - offset);
+
+ kstd::vector<std::byte> scratch_buffer{block_size};
+ auto processed = 0uz;
+
+ while (processed < total_to_process)
+ {
+ size_t const absolute_offset = offset + processed;
+ size_t const block_index = absolute_offset / block_size;
+ size_t const in_block_offset = absolute_offset % block_size;
+ size_t const chunk_size = std::min(total_to_process - processed, block_size - in_block_offset);
+
+ op(block_index, in_block_offset, chunk_size, processed, block_dev, scratch_buffer.data(), buffer);
+
+ processed += chunk_size;
+ }
+
+ return processed;
+ }
+
+ auto read(kstd::shared_ptr<kapi::devices::device> const & device, void * buffer, size_t offset, size_t size) -> size_t
+ {
+ return process_blocks(device, offset, size, buffer,
+ [](size_t idx, size_t off, size_t len, size_t done, devices::block_device * device,
+ std::byte * scratch, void * buffer) {
+ auto * out = static_cast<std::byte *>(buffer);
+ if (off == 0 && len == device->block_size())
+ {
+ device->read_block(idx, out + done);
+ }
+ else
+ {
+ device->read_block(idx, scratch);
+ kstd::libc::memcpy(out + done, scratch + off, len);
+ }
+ });
+ }
+
+ auto write(kstd::shared_ptr<kapi::devices::device> const & device, void const * buffer, size_t offset, size_t size)
+ -> size_t
+ {
+ return process_blocks(device, offset, size, const_cast<void *>(buffer),
+ [](size_t idx, size_t off, size_t len, size_t done, devices::block_device * device,
+ std::byte * scratch, void * buffer) {
+ auto const * in = static_cast<std::byte const *>(buffer);
+ if (off == 0 && len == device->block_size())
+ {
+ device->write_block(idx, in + done);
+ }
+ else
+ {
+ device->read_block(idx, scratch);
+ kstd::libc::memcpy(scratch + off, in + done, len);
+ device->write_block(idx, scratch);
+ }
+ });
+ }
+
+} // namespace kernel::devices::block_device_utils \ No newline at end of file
diff --git a/kernel/src/devices/block_device_utils.tests.cpp b/kernel/src/devices/block_device_utils.tests.cpp
new file mode 100644
index 0000000..e2e1e65
--- /dev/null
+++ b/kernel/src/devices/block_device_utils.tests.cpp
@@ -0,0 +1,219 @@
+#include <kernel/devices/block_device_utils.hpp>
+
+#include <kernel/test_support/cpu.hpp>
+#include <kernel/test_support/devices/block_device.hpp>
+#include <kernel/test_support/devices/character_device.hpp>
+
+#include <kstd/memory>
+#include <kstd/print>
+#include <kstd/vector>
+
+#include <catch2/catch_test_macros.hpp>
+
+#include <cstddef>
+#include <cstdint>
+
+SCENARIO("reading from a block device with block_device_utils", "[devices][block_device_utils]")
+{
+ GIVEN("a block device with known data")
+ {
+ auto const block_size = 512;
+ auto device = kstd::make_shared<kernel::tests::devices::block_device>(0, 0, "test_block_device", block_size);
+ kstd::vector<uint8_t> block_data(block_size);
+ for (size_t i = 0; i < block_data.size(); ++i)
+ {
+ block_data[i] = static_cast<uint8_t>(i % 256);
+ }
+ device->write_block(0, block_data.data());
+ device->write_block(1, block_data.data());
+
+ WHEN("reading from the block device using block_device_utils")
+ {
+ kstd::vector<uint8_t> read_buffer(block_size);
+ auto bytes_read = kernel::devices::block_device_utils::read(device, read_buffer.data(), 0, read_buffer.size());
+
+ THEN("the correct number of bytes is read")
+ {
+ REQUIRE(bytes_read == read_buffer.size());
+ }
+
+ THEN("the data read matches the data written to the block device")
+ {
+ REQUIRE(read_buffer == block_data);
+ }
+ }
+
+ WHEN("reading over block boundaries")
+ {
+ kstd::vector<uint8_t> read_buffer(1024);
+ auto bytes_read = kernel::devices::block_device_utils::read(device, read_buffer.data(), 256, read_buffer.size());
+
+ THEN("the correct number of bytes is read")
+ {
+ REQUIRE(bytes_read == 1.5 * block_size);
+ }
+
+ THEN("the data read matches the expected data across block boundaries")
+ {
+ for (size_t i = 0; i < bytes_read; ++i)
+ {
+ uint8_t expected_value = static_cast<uint8_t>((256 + i) % 256);
+ REQUIRE(read_buffer[i] == expected_value);
+ }
+ }
+ }
+
+ WHEN("reading beyond the device capacity")
+ {
+ kstd::vector<uint8_t> read_buffer(block_size);
+ auto bytes_read = kernel::devices::block_device_utils::read(device, read_buffer.data(), 1024, read_buffer.size());
+
+ THEN("no bytes are read")
+ {
+ REQUIRE(bytes_read == 0);
+ }
+ }
+
+ WHEN("reading nothing")
+ {
+ kstd::vector<uint8_t> read_buffer(block_size);
+ auto bytes_read = kernel::devices::block_device_utils::read(device, read_buffer.data(), 0, 0);
+
+ THEN("no bytes are read")
+ {
+ REQUIRE(bytes_read == 0);
+ }
+ }
+
+ WHEN("reading with a null buffer")
+ {
+ THEN("the system panics")
+ {
+ REQUIRE_THROWS_AS(kernel::devices::block_device_utils::read(device, nullptr, 0, 512), kernel::tests::cpu::halt);
+ }
+ }
+ }
+}
+
+SCENARIO("writing to a block device using block_device_utils", "[devices][block_device_utils]")
+{
+ GIVEN("a block device")
+ {
+ auto const block_size = 512;
+ auto device =
+ kstd::make_shared<kernel::tests::devices::block_device>(0, 0, "test_block_device", block_size, 2 * block_size);
+
+ WHEN("writing to the block device using block_device_utils")
+ {
+ kstd::vector<uint8_t> write_buffer(block_size);
+ for (size_t i = 0; i < write_buffer.size(); ++i)
+ {
+ write_buffer[i] = static_cast<uint8_t>(i % 256);
+ }
+
+ auto bytes_written =
+ kernel::devices::block_device_utils::write(device, write_buffer.data(), 0, write_buffer.size());
+
+ THEN("the correct number of bytes is written")
+ {
+ REQUIRE(bytes_written == write_buffer.size());
+ }
+
+ THEN("the data written matches the data read back from the block device")
+ {
+ kstd::vector<uint8_t> read_buffer(block_size);
+ device->read_block(0, read_buffer.data());
+ REQUIRE(read_buffer == write_buffer);
+ }
+ }
+
+ WHEN("writing over block boundaries")
+ {
+ kstd::vector<uint8_t> write_buffer(2 * block_size);
+ for (size_t i = 0; i < write_buffer.size(); ++i)
+ {
+ write_buffer[i] = static_cast<uint8_t>(i % 256);
+ }
+
+ auto bytes_written =
+ kernel::devices::block_device_utils::write(device, write_buffer.data(), 256, write_buffer.size());
+
+ THEN("the correct number of bytes is written")
+ {
+ REQUIRE(bytes_written == 1.5 * block_size);
+ }
+
+ THEN("the data written matches the data read back from the block device across block boundaries")
+ {
+ kstd::vector<uint8_t> read_buffer(2 * block_size);
+ auto bytes_read = kernel::devices::block_device_utils::read(device, read_buffer.data(), 256, 2 * block_size);
+
+ for (size_t i = 0; i < bytes_read; ++i)
+ {
+ REQUIRE(read_buffer[i] == write_buffer[i]);
+ }
+ }
+ }
+
+ WHEN("writing beyond the device capacity")
+ {
+ kstd::vector<uint8_t> write_buffer(block_size);
+ auto bytes_written =
+ kernel::devices::block_device_utils::write(device, write_buffer.data(), 1024, write_buffer.size());
+
+ THEN("no bytes are written")
+ {
+ REQUIRE(bytes_written == 0);
+ }
+ }
+
+ WHEN("writing nothing")
+ {
+ kstd::vector<uint8_t> write_buffer(block_size);
+ auto bytes_written = kernel::devices::block_device_utils::write(device, write_buffer.data(), 0, 0);
+
+ THEN("no bytes are written")
+ {
+ REQUIRE(bytes_written == 0);
+ }
+ }
+
+ WHEN("writing with a null buffer")
+ {
+ THEN("the system panics")
+ {
+ REQUIRE_THROWS_AS(kernel::devices::block_device_utils::write(device, nullptr, 0, block_size),
+ kernel::tests::cpu::halt);
+ }
+ }
+ }
+}
+
+SCENARIO("block_device_utils with a non-block device", "[devices][block_device_utils]")
+{
+ GIVEN("a non-block device")
+ {
+ auto device = kstd::make_shared<kernel::tests::devices::character_device>(0, 0, "test_character_device");
+
+ WHEN("attempting to read from the non-block device using block_device_utils")
+ {
+ kstd::vector<uint8_t> read_buffer(512);
+ THEN("the system panics")
+ {
+ REQUIRE_THROWS_AS(kernel::devices::block_device_utils::read(device, read_buffer.data(), 0, read_buffer.size()),
+ kernel::tests::cpu::halt);
+ }
+ }
+
+ WHEN("attempting to write to the non-block device using block_device_utils")
+ {
+ kstd::vector<uint8_t> write_buffer(512);
+ THEN("the system panics")
+ {
+ REQUIRE_THROWS_AS(
+ kernel::devices::block_device_utils::write(device, write_buffer.data(), 0, write_buffer.size()),
+ kernel::tests::cpu::halt);
+ }
+ }
+ }
+}
diff --git a/kernel/src/devices/root_bus.cpp b/kernel/src/devices/root_bus.cpp
new file mode 100644
index 0000000..1b754f2
--- /dev/null
+++ b/kernel/src/devices/root_bus.cpp
@@ -0,0 +1,12 @@
+#include <kernel/devices/root_bus.hpp>
+
+#include <kapi/devices.hpp>
+
+namespace kernel::devices
+{
+
+ root_bus::root_bus()
+ : kapi::devices::bus{0, 0, "system"}
+ {}
+
+} // namespace kernel::devices \ No newline at end of file
diff --git a/kernel/src/devices/storage/controller.cpp b/kernel/src/devices/storage/controller.cpp
new file mode 100644
index 0000000..171b918
--- /dev/null
+++ b/kernel/src/devices/storage/controller.cpp
@@ -0,0 +1,44 @@
+#include <kernel/devices/storage/controller.hpp>
+
+#include <kapi/devices/device.hpp>
+
+#include <kstd/memory>
+#include <kstd/vector>
+
+#include <algorithm>
+#include <cstddef>
+
+namespace kernel::devices::storage
+{
+ auto controller::set_ids(size_t major, size_t minors_per_dev) -> void
+ {
+ m_major = major;
+ m_minors_per_device = minors_per_dev;
+ }
+
+ auto controller::major() const -> size_t
+ {
+ return m_major;
+ }
+
+ auto controller::device_by_minor(size_t minor) const -> kstd::shared_ptr<kapi::devices::device>
+ {
+ auto it = std::ranges::find_if(m_devices, [minor](auto const & device) { return device->minor() == minor; });
+
+ if (it != m_devices.end())
+ {
+ return *it;
+ }
+ return nullptr;
+ }
+
+ auto controller::devices_count() const -> size_t
+ {
+ return m_devices.size();
+ }
+
+ auto controller::all_devices() const -> kstd::vector<kstd::shared_ptr<kapi::devices::device>> const &
+ {
+ return m_devices;
+ }
+} // namespace kernel::devices::storage \ No newline at end of file
diff --git a/kernel/src/devices/storage/management.cpp b/kernel/src/devices/storage/management.cpp
new file mode 100644
index 0000000..06efc27
--- /dev/null
+++ b/kernel/src/devices/storage/management.cpp
@@ -0,0 +1,95 @@
+#include <kernel/devices/storage/management.hpp>
+
+#include <kernel/devices/storage/controller.hpp>
+#include <kernel/devices/storage/ram_disk/controller.hpp>
+
+#include <kapi/boot_modules.hpp>
+#include <kapi/devices/device.hpp>
+#include <kapi/system.hpp>
+
+#include <kstd/memory>
+#include <kstd/vector>
+
+#include <algorithm>
+#include <cstddef>
+#include <optional>
+#include <ranges>
+
+namespace
+{
+ constexpr size_t static minors_per_device = 16;
+ constexpr size_t static start_major = 1;
+ constinit size_t static next_free_major = start_major;
+
+ constinit auto static storage_management = std::optional<kernel::devices::storage::management>{};
+} // namespace
+
+namespace kernel::devices::storage
+{
+ auto management::init() -> void
+ {
+ if (storage_management)
+ {
+ kapi::system::panic("[DEVICES] Storage management has already been initialized.");
+ }
+ storage_management.emplace(management{});
+
+ auto ram_disk_controller = kstd::make_shared<ram_disk::controller>(&kapi::boot_modules::get_boot_module_registry());
+ storage_management->add_controller(ram_disk_controller);
+
+ std::ranges::for_each(storage_management->m_controllers, [](auto controller) { controller->probe(); });
+ }
+
+ auto management::get() -> management &
+ {
+ if (!storage_management)
+ {
+ kapi::system::panic("[DEVICES] Storage management has not been initialized.");
+ }
+
+ return *storage_management;
+ }
+
+ auto management::add_controller(kstd::shared_ptr<controller> const & controller) -> void
+ {
+ controller->set_ids(next_free_major++, minors_per_device);
+ m_controllers.push_back(controller);
+ }
+
+ auto management::all_controllers() const -> kstd::vector<kstd::shared_ptr<controller>> const &
+ {
+ return m_controllers;
+ }
+
+ auto management::device_by_major_minor(size_t major, size_t minor) -> kstd::shared_ptr<kapi::devices::device>
+ {
+ auto found = std::ranges::find_if(m_controllers, [=](auto const & controller) {
+ if (controller != nullptr && controller->major() == major)
+ {
+ return controller->device_by_minor(minor) != nullptr;
+ }
+ return false;
+ });
+
+ if (found != std::ranges::cend(m_controllers))
+ {
+ return found->get()->device_by_minor(minor);
+ }
+
+ return nullptr;
+ }
+
+ auto management::determine_boot_device() -> kstd::shared_ptr<kapi::devices::device>
+ {
+ return device_by_major_minor(start_major, 0);
+ }
+} // namespace kernel::devices::storage
+
+namespace kernel::tests::devices::storage::management
+{
+ auto deinit() -> void
+ {
+ storage_management.reset();
+ next_free_major = start_major;
+ }
+} // namespace kernel::tests::devices::storage::management
diff --git a/kernel/src/devices/storage/ram_disk/controller.cpp b/kernel/src/devices/storage/ram_disk/controller.cpp
new file mode 100644
index 0000000..30441fa
--- /dev/null
+++ b/kernel/src/devices/storage/ram_disk/controller.cpp
@@ -0,0 +1,27 @@
+#include <kernel/devices/storage/ram_disk/controller.hpp>
+
+#include <kernel/devices/storage/ram_disk/device.hpp>
+
+#include <kapi/boot_module/boot_module_registry.hpp>
+
+#include <kstd/memory>
+
+#include <algorithm>
+#include <cstddef>
+
+namespace kernel::devices::storage::ram_disk
+{
+ controller::controller(kapi::boot_modules::boot_module_registry const * registry)
+ : m_boot_module_registry(registry)
+ {}
+
+ auto controller::probe() -> void
+ {
+ size_t current_device_index = 0;
+
+ std::ranges::for_each(*m_boot_module_registry, [this, &current_device_index](auto const & module) {
+ auto const minor = current_device_index++ * m_minors_per_device;
+ m_devices.push_back(kstd::make_shared<device>(module, m_major, minor));
+ });
+ }
+} // namespace kernel::devices::storage::ram_disk \ No newline at end of file
diff --git a/kernel/src/devices/storage/ram_disk/device.cpp b/kernel/src/devices/storage/ram_disk/device.cpp
new file mode 100644
index 0000000..1557204
--- /dev/null
+++ b/kernel/src/devices/storage/ram_disk/device.cpp
@@ -0,0 +1,71 @@
+#include <kernel/devices/storage/ram_disk/device.hpp>
+
+#include <kernel/devices/block_device.hpp>
+
+#include <kapi/boot_module/boot_module.hpp>
+#include <kapi/system.hpp>
+
+#include <kstd/cstring>
+#include <kstd/string>
+
+#include <cstddef>
+
+namespace kernel::devices::storage::ram_disk
+{
+ namespace
+ {
+ constexpr size_t ram_disk_block_size = 512uz;
+ } // namespace
+
+ device::device(kapi::boot_modules::boot_module const & module, size_t major, size_t minor)
+ : block_device(major, minor, "ram" + kstd::to_string(minor), ram_disk_block_size)
+ , m_boot_module(module)
+ {}
+
+ auto device::init() -> bool
+ {
+ return m_boot_module.start_address.raw() != 0 && m_boot_module.size > 0;
+ }
+
+ auto device::read_block(size_t block_index, void * buffer) const -> void
+ {
+ if (buffer == nullptr)
+ {
+ kapi::system::panic("[RAM DISK DEVICE] read_block called with null buffer.");
+ }
+
+ auto const info = calculate_transfer(block_index);
+
+ if (info.to_transfer > 0)
+ {
+ auto const src = static_cast<std::byte const *>(m_boot_module.start_address) + info.offset;
+ kstd::libc::memcpy(buffer, src, info.to_transfer);
+ }
+
+ if (info.remainder > 0)
+ {
+ kstd::libc::memset(static_cast<std::byte *>(buffer) + info.to_transfer, 0, info.remainder);
+ }
+ }
+
+ auto device::write_block(size_t block_index, void const * buffer) -> void
+ {
+ if (buffer == nullptr)
+ {
+ kapi::system::panic("[RAM DISK DEVICE] write_block called with null buffer.");
+ }
+
+ auto const info = calculate_transfer(block_index);
+
+ if (info.to_transfer > 0)
+ {
+ auto const dest = static_cast<std::byte *>(m_boot_module.start_address) + info.offset;
+ kstd::libc::memcpy(dest, buffer, info.to_transfer);
+ }
+ }
+
+ auto device::size() const -> size_t
+ {
+ return m_boot_module.size;
+ }
+} // namespace kernel::devices::storage::ram_disk \ No newline at end of file
diff --git a/kernel/src/devices/storage/ram_disk/device.tests.cpp b/kernel/src/devices/storage/ram_disk/device.tests.cpp
new file mode 100644
index 0000000..d0fab76
--- /dev/null
+++ b/kernel/src/devices/storage/ram_disk/device.tests.cpp
@@ -0,0 +1,116 @@
+#include <kernel/devices/storage/ram_disk/device.hpp>
+
+#include <kapi/boot_module/boot_module.hpp>
+#include <kapi/memory.hpp>
+
+#include <catch2/catch_test_macros.hpp>
+#include <catch2/matchers/catch_matchers.hpp>
+#include <catch2/matchers/catch_matchers_range_equals.hpp>
+
+#include <cstddef>
+#include <ranges>
+#include <stdexcept>
+#include <vector>
+
+SCENARIO("RAM Disk Device Construction and Initialization", "[ram_disk_device]")
+{
+ GIVEN("an empty boot module")
+ {
+ kapi::boot_modules::boot_module boot_module{};
+ boot_module.start_address = kapi::memory::linear_address{nullptr};
+ boot_module.size = 0;
+
+ WHEN("constructing the device")
+ {
+ kernel::devices::storage::ram_disk::device device{boot_module, 0, 0};
+
+ THEN("init return false")
+ {
+ REQUIRE_FALSE(device.init());
+ }
+ }
+ }
+
+ GIVEN("a boot module with a valid start address and size")
+ {
+ kapi::boot_modules::boot_module boot_module{};
+ boot_module.start_address = kapi::memory::linear_address{reinterpret_cast<std::byte *>(0x1000)};
+ boot_module.size = 512;
+
+ WHEN("constructing the device")
+ {
+ kernel::devices::storage::ram_disk::device device{boot_module, 0, 0};
+
+ THEN("init return true")
+ {
+ REQUIRE(device.init());
+ }
+ }
+ }
+}
+
+SCENARIO("RAM Disk Device Read and Write", "[ram_disk_device]")
+{
+ GIVEN("a device initialized with a valid boot module")
+ {
+ auto storage = std::vector{4096, std::byte{0xff}};
+ auto module =
+ kapi::boot_modules::boot_module{"test_module", kapi::memory::linear_address{storage.data()}, storage.size()};
+ auto device = kernel::devices::storage::ram_disk::device{module, 0, 0};
+ REQUIRE(device.init());
+
+ WHEN("reading a full block from the device")
+ {
+ auto buffer = std::vector<std::byte>(device.block_size());
+ device.read_block(0, buffer.data());
+
+ THEN("the buffer is filled with the module data")
+ {
+ REQUIRE_THAT(buffer, Catch::Matchers::RangeEquals(std::views::take(storage, device.block_size())));
+ }
+ }
+
+ WHEN("reading from a block index beyond the module size")
+ {
+ auto buffer = std::vector<std::byte>(device.block_size());
+ device.read_block(10, buffer.data());
+
+ THEN("the buffer is filled with zeros")
+ {
+ REQUIRE_THAT(buffer, Catch::Matchers::RangeEquals(std::vector<std::byte>(device.block_size(), std::byte{0})));
+ }
+ }
+
+ WHEN("reading into a null buffer")
+ {
+ REQUIRE_THROWS_AS(device.read_block(0, nullptr), std::runtime_error);
+ }
+
+ WHEN("writing to a full block")
+ {
+ auto buffer = std::vector<std::byte>(device.block_size(), std::byte{0x01});
+ device.write_block(0, buffer.data());
+
+ THEN("the module data is updated")
+ {
+ REQUIRE_THAT(std::views::take(storage, device.block_size()), Catch::Matchers::RangeEquals(buffer));
+ }
+ }
+
+ WHEN("writing to a block index beyond the module size")
+ {
+ auto buffer = std::vector<std::byte>(device.block_size(), std::byte{0x01});
+ device.write_block(10, buffer.data());
+
+ THEN("the module data is not updated")
+ {
+ REQUIRE_THAT(storage, Catch::Matchers::RangeEquals(std::vector{4096, std::byte{0xff}}));
+ }
+ }
+
+ WHEN("writing from a null buffer")
+ {
+ REQUIRE_THROWS_AS(device.write_block(0, nullptr), std::runtime_error);
+ }
+ }
+} \ No newline at end of file
diff --git a/kernel/src/filesystem/dentry.cpp b/kernel/src/filesystem/dentry.cpp
new file mode 100644
index 0000000..3d8e01a
--- /dev/null
+++ b/kernel/src/filesystem/dentry.cpp
@@ -0,0 +1,95 @@
+#include <kernel/filesystem/dentry.hpp>
+
+#include <kernel/filesystem/inode.hpp>
+
+#include <kapi/system.hpp>
+
+#include <kstd/memory>
+#include <kstd/string>
+
+#include <algorithm>
+#include <cstdint>
+#include <string_view>
+
+namespace kernel::filesystem
+{
+ dentry::dentry(kstd::shared_ptr<dentry> const & parent, kstd::shared_ptr<inode> const & inode, std::string_view name)
+ : m_name(name)
+ , m_parent(parent)
+ , m_inode(inode)
+ , m_flags(0)
+ {
+ if (!m_inode)
+ {
+ kapi::system::panic("[FILESYSTEM] dentry constructed with null inode.");
+ }
+ if (m_name.empty())
+ {
+ kapi::system::panic("[FILESYSTEM] dentry constructed with empty name.");
+ }
+ }
+
+ auto dentry::get_inode() const -> kstd::shared_ptr<inode> const &
+ {
+ return m_inode;
+ }
+
+ auto dentry::parent() const -> kstd::shared_ptr<dentry> const &
+ {
+ return m_parent;
+ }
+
+ auto dentry::name() const -> std::string_view
+ {
+ return m_name;
+ }
+
+ auto dentry::absolute_path() const -> kstd::string
+ {
+ kstd::string path = m_name;
+
+ auto parent = m_parent;
+ while (parent)
+ {
+ auto parent_name = parent->m_name;
+ if (parent_name == "/")
+ {
+ path = "/" + path;
+ }
+ else
+ {
+ path = parent_name + "/" + path;
+ }
+
+ parent = parent->m_parent;
+ }
+
+ return path;
+ }
+
+ auto dentry::add_child(kstd::shared_ptr<dentry> const & child) -> void
+ {
+ m_children.push_back(child);
+ }
+
+ auto dentry::find_child(std::string_view name) const -> kstd::shared_ptr<dentry>
+ {
+ auto it = std::ranges::find_if(m_children, [&](auto const & child) { return child->m_name == name; });
+ return (it != m_children.end()) ? *it : nullptr;
+ }
+
+ auto dentry::set_flag(dentry_flags flag) -> void
+ {
+ m_flags |= static_cast<uint32_t>(flag);
+ }
+
+ auto dentry::unset_flag(dentry_flags flag) -> void
+ {
+ m_flags &= ~static_cast<uint32_t>(flag);
+ }
+
+ auto dentry::has_flag(dentry_flags flag) const -> bool
+ {
+ return (m_flags & static_cast<uint32_t>(flag)) != 0;
+ }
+} // namespace kernel::filesystem \ No newline at end of file
diff --git a/kernel/src/filesystem/dentry.tests.cpp b/kernel/src/filesystem/dentry.tests.cpp
new file mode 100644
index 0000000..b7690f5
--- /dev/null
+++ b/kernel/src/filesystem/dentry.tests.cpp
@@ -0,0 +1,150 @@
+#include <kernel/filesystem/dentry.hpp>
+
+#include <kernel/test_support/cpu.hpp>
+#include <kernel/test_support/filesystem/inode.hpp>
+
+#include <kstd/memory>
+#include <kstd/print>
+
+#include <catch2/catch_test_macros.hpp>
+
+SCENARIO("Dentry construction", "[filesystem][dentry]")
+{
+ GIVEN("A parent dentry and inode")
+ {
+ auto inode = kstd::make_shared<kernel::tests::filesystem::inode>();
+ auto parent_dentry = kstd::make_shared<kernel::filesystem::dentry>(nullptr, inode, "parent");
+
+ WHEN("constructing a dentry")
+ {
+ auto child_dentry = kernel::filesystem::dentry{parent_dentry, inode, "child"};
+
+ THEN("the dentry has the correct parent, inode, and name")
+ {
+ REQUIRE(child_dentry.parent() == parent_dentry);
+ REQUIRE(child_dentry.get_inode() == inode);
+ REQUIRE(child_dentry.name() == "child");
+ }
+
+ THEN("no flag is set")
+ {
+ REQUIRE_FALSE(child_dentry.has_flag(kernel::filesystem::dentry::dentry_flags::is_mount_point));
+ }
+ }
+
+ WHEN("constructing a dentry with an empty name")
+ {
+ THEN("the dentry has the correct parent and inode, and an empty name")
+ {
+ REQUIRE_THROWS_AS((kernel::filesystem::dentry{parent_dentry, inode, ""}), kernel::tests::cpu::halt);
+ }
+ }
+
+ WHEN("constructing a dentry with a null parent")
+ {
+ auto child_dentry = kernel::filesystem::dentry{nullptr, inode, "child"};
+
+ THEN("the dentry has a null parent, the correct inode, and the correct name")
+ {
+ REQUIRE(child_dentry.parent() == nullptr);
+ REQUIRE(child_dentry.get_inode() == inode);
+ REQUIRE(child_dentry.name() == "child");
+ }
+
+ THEN("no flag is set")
+ {
+ REQUIRE_FALSE(child_dentry.has_flag(kernel::filesystem::dentry::dentry_flags::is_mount_point));
+ }
+ }
+
+ WHEN("constructing a dentry with a null inode")
+ {
+ THEN("the system panics")
+ {
+ REQUIRE_THROWS_AS((kernel::filesystem::dentry{parent_dentry, nullptr, "child"}), kernel::tests::cpu::halt);
+ }
+ }
+ }
+}
+
+SCENARIO("Dentry child logic", "[filesystem][dentry]")
+{
+ GIVEN("A parent dentry and inode")
+ {
+ auto inode = kstd::make_shared<kernel::tests::filesystem::inode>();
+ auto parent_dentry = kstd::make_shared<kernel::filesystem::dentry>(nullptr, inode, "parent");
+
+ WHEN("adding child dentries")
+ {
+ auto child1 = kstd::make_shared<kernel::filesystem::dentry>(parent_dentry, inode, "child1");
+ auto child2 = kstd::make_shared<kernel::filesystem::dentry>(parent_dentry, inode, "child2");
+ parent_dentry->add_child(child1);
+ parent_dentry->add_child(child2);
+
+ THEN("the children can be found by name")
+ {
+ REQUIRE(parent_dentry->find_child("child1") == child1);
+ REQUIRE(parent_dentry->find_child("child2") == child2);
+ }
+
+ THEN("finding a non-existent child returns null")
+ {
+ REQUIRE(parent_dentry->find_child("nonexistent") == nullptr);
+ }
+ }
+ }
+}
+
+SCENARIO("Dentry Flag logic", "[filesystem][dentry]")
+{
+ GIVEN("A dentry")
+ {
+ auto inode = kstd::make_shared<kernel::tests::filesystem::inode>();
+ auto dentry = kernel::filesystem::dentry{nullptr, inode, "test"};
+
+ WHEN("setting a flag")
+ {
+ dentry.set_flag(kernel::filesystem::dentry::dentry_flags::is_mount_point);
+
+ THEN("the flag is set")
+ {
+ REQUIRE(dentry.has_flag(kernel::filesystem::dentry::dentry_flags::is_mount_point));
+ }
+ }
+
+ WHEN("unsetting a flag")
+ {
+ dentry.set_flag(kernel::filesystem::dentry::dentry_flags::is_mount_point);
+ dentry.unset_flag(kernel::filesystem::dentry::dentry_flags::is_mount_point);
+
+ THEN("the flag is unset")
+ {
+ REQUIRE_FALSE(dentry.has_flag(kernel::filesystem::dentry::dentry_flags::is_mount_point));
+ }
+ }
+ }
+}
+
+SCENARIO("Dentry path resolution", "[filesystem][dentry]")
+{
+ GIVEN("A dentry with a parent hierarchy")
+ {
+ auto root_inode = kstd::make_shared<kernel::tests::filesystem::inode>();
+ auto root_dentry = kstd::make_shared<kernel::filesystem::dentry>(nullptr, root_inode, "/");
+
+ auto home_inode = kstd::make_shared<kernel::tests::filesystem::inode>();
+ auto home_dentry = kstd::make_shared<kernel::filesystem::dentry>(root_dentry, home_inode, "home");
+ root_dentry->add_child(home_dentry);
+
+ auto user_inode = kstd::make_shared<kernel::tests::filesystem::inode>();
+ auto user_dentry = kstd::make_shared<kernel::filesystem::dentry>(home_dentry, user_inode, "user");
+ home_dentry->add_child(user_dentry);
+
+ THEN("the full path is constructed correctly")
+ {
+ REQUIRE(root_dentry->absolute_path() == "/");
+ REQUIRE(home_dentry->absolute_path() == "/home");
+ REQUIRE(user_dentry->absolute_path() == "/home/user");
+ }
+ }
+} \ No newline at end of file
diff --git a/kernel/src/filesystem/devfs/filesystem.cpp b/kernel/src/filesystem/devfs/filesystem.cpp
new file mode 100644
index 0000000..ce887ff
--- /dev/null
+++ b/kernel/src/filesystem/devfs/filesystem.cpp
@@ -0,0 +1,81 @@
+#include <kernel/filesystem/devfs/filesystem.hpp>
+
+#include "kernel/filesystem/filesystem.hpp"
+#include <kernel/devices/storage/management.hpp>
+#include <kernel/filesystem/devfs/inode.hpp>
+#include <kernel/filesystem/device_inode.hpp>
+#include <kernel/filesystem/inode.hpp>
+#include <kernel/filesystem/type.hpp>
+
+#include <kapi/devices/device.hpp>
+
+#include <kstd/memory>
+
+#include <algorithm>
+#include <string_view>
+
+namespace kernel::filesystem::devfs
+{
+ struct type final : kernel::filesystem::type
+ {
+ [[nodiscard]] auto name() const noexcept -> std::string_view override
+ {
+ return "devfs";
+ }
+
+ [[nodiscard]] auto requires_device() const noexcept -> bool override
+ {
+ return false;
+ }
+
+ [[nodiscard]] auto make_instance() const -> kstd::shared_ptr<kernel::filesystem::filesystem> override
+ {
+ return kstd::make_shared<filesystem>();
+ }
+ };
+
+ [[gnu::used]]
+ constexpr auto registration = type_registration<type>{};
+
+ auto filesystem::mount(kstd::shared_ptr<kernel::filesystem::inode> const &) -> operation_result
+ {
+ m_root_inode = kstd::make_shared<inode>();
+ build_device_inode_table();
+
+ return operation_result::success;
+ }
+
+ auto filesystem::lookup(kstd::shared_ptr<kernel::filesystem::inode> const & parent, std::string_view name) const
+ -> kstd::shared_ptr<kernel::filesystem::inode>
+ {
+ if (!parent || !parent->is_directory())
+ {
+ return nullptr;
+ }
+
+ if (parent.get() != m_root_inode.get())
+ {
+ return nullptr;
+ }
+
+ auto it = std::ranges::find_if(m_inodes, [&](auto const & dev_node) {
+ if (auto device_inode_ptr = static_cast<device_inode *>(dev_node.get()))
+ {
+ return device_inode_ptr->device()->name() == name;
+ }
+ return false;
+ });
+ return (it != m_inodes.end()) ? *it : nullptr;
+ }
+
+ auto filesystem::build_device_inode_table() -> void
+ {
+ m_inodes.clear();
+
+ auto storage_mgmt = devices::storage::management::get();
+ std::ranges::for_each(storage_mgmt.all_controllers(), [&](auto const & controller) {
+ std::ranges::for_each(controller->all_devices(),
+ [&](auto const & device) { m_inodes.push_back(kstd::make_shared<device_inode>(device)); });
+ });
+ }
+} // namespace kernel::filesystem::devfs \ No newline at end of file
diff --git a/kernel/src/filesystem/devfs/filesystem.tests.cpp b/kernel/src/filesystem/devfs/filesystem.tests.cpp
new file mode 100644
index 0000000..36cb411
--- /dev/null
+++ b/kernel/src/filesystem/devfs/filesystem.tests.cpp
@@ -0,0 +1,72 @@
+#include <kernel/filesystem/devfs/filesystem.hpp>
+
+#include <kernel/filesystem/filesystem.hpp>
+#include <kernel/test_support/filesystem/storage_boot_module_fixture.hpp>
+
+#include <catch2/catch_test_macros.hpp>
+
+SCENARIO_METHOD(kernel::tests::filesystem::storage_boot_module_fixture,
+ "Devfs filesystem lookup uses storage management devices", "[filesystem][devfs][filesystem]")
+{
+ GIVEN("a boot module registry with one module")
+ {
+ setup_modules(1);
+
+ auto fs = kernel::filesystem::devfs::filesystem{};
+ auto result = fs.mount(nullptr);
+
+ THEN("mount succeeds")
+ {
+ REQUIRE(result == kernel::filesystem::filesystem::operation_result::success);
+ REQUIRE(fs.root_inode() != nullptr);
+ }
+
+ THEN("lookup on root finds ram0 device inode")
+ {
+ auto inode = fs.lookup(fs.root_inode(), "ram0");
+ REQUIRE(inode != nullptr);
+ REQUIRE(inode->is_device());
+ }
+
+ THEN("lookup of an unknown device returns null")
+ {
+ auto inode = fs.lookup(fs.root_inode(), "ram99");
+ REQUIRE(inode == nullptr);
+ }
+
+ THEN("lookup with wrong parent returns null")
+ {
+ auto other_fs = kernel::filesystem::devfs::filesystem{};
+ other_fs.mount(nullptr);
+
+ auto inode = fs.lookup(other_fs.root_inode(), "ram0");
+ REQUIRE(inode == nullptr);
+ }
+
+ THEN("lookup with a non-directory parent returns null")
+ {
+ auto non_directory_inode = fs.lookup(fs.root_inode(), "ram0");
+ REQUIRE(non_directory_inode != nullptr);
+ REQUIRE_FALSE(non_directory_inode->is_directory());
+
+ auto result = fs.lookup(non_directory_inode, "anything");
+ REQUIRE(result == nullptr);
+ }
+ }
+
+ GIVEN("a boot module registry with three modules")
+ {
+ setup_modules(3, 2048);
+
+ auto fs = kernel::filesystem::devfs::filesystem{};
+ auto result = fs.mount(nullptr);
+ REQUIRE(result == kernel::filesystem::filesystem::operation_result::success);
+
+ THEN("lookup finds all generated RAM devices")
+ {
+ REQUIRE(fs.lookup(fs.root_inode(), "ram0") != nullptr);
+ REQUIRE(fs.lookup(fs.root_inode(), "ram16") != nullptr);
+ REQUIRE(fs.lookup(fs.root_inode(), "ram32") != nullptr);
+ }
+ }
+}
diff --git a/kernel/src/filesystem/devfs/inode.cpp b/kernel/src/filesystem/devfs/inode.cpp
new file mode 100644
index 0000000..7bbfbbe
--- /dev/null
+++ b/kernel/src/filesystem/devfs/inode.cpp
@@ -0,0 +1,21 @@
+#include <kernel/filesystem/devfs/inode.hpp>
+
+#include <cstddef>
+
+namespace kernel::filesystem::devfs
+{
+ auto inode::read(void *, size_t, size_t) const -> size_t
+ {
+ return 0;
+ }
+
+ auto inode::write(void const *, size_t, size_t) -> size_t
+ {
+ return 0;
+ }
+
+ auto inode::is_directory() const -> bool
+ {
+ return true;
+ }
+} // namespace kernel::filesystem::devfs \ No newline at end of file
diff --git a/kernel/src/filesystem/devfs/inode.tests.cpp b/kernel/src/filesystem/devfs/inode.tests.cpp
new file mode 100644
index 0000000..ae26e74
--- /dev/null
+++ b/kernel/src/filesystem/devfs/inode.tests.cpp
@@ -0,0 +1,55 @@
+#include <kernel/filesystem/devfs/inode.hpp>
+
+#include <kstd/memory>
+#include <kstd/print>
+#include <kstd/vector>
+
+#include <catch2/catch_test_macros.hpp>
+
+#include <cstdint>
+
+SCENARIO("Devfs inode creation", "[filesystem][devfs][inode]")
+{
+ GIVEN("a devfs inode")
+ {
+ auto inode = kernel::filesystem::devfs::inode{};
+
+ THEN("the inode has the correct kind")
+ {
+ REQUIRE(inode.is_directory());
+ REQUIRE_FALSE(inode.is_device());
+ REQUIRE_FALSE(inode.is_regular());
+ REQUIRE_FALSE(inode.is_symbolic_link());
+ }
+ }
+}
+
+SCENARIO("Devfs inode read/write", "[filesystem][devfs][inode]")
+{
+ GIVEN("a devfs inode")
+ {
+ auto inode = kernel::filesystem::devfs::inode{};
+
+ WHEN("attempting to read from the devfs inode")
+ {
+ kstd::vector<uint8_t> buffer(512);
+ auto bytes_read = inode.read(buffer.data(), 0, buffer.size());
+
+ THEN("no bytes are read")
+ {
+ REQUIRE(bytes_read == 0);
+ }
+ }
+
+ WHEN("attempting to write to the devfs inode")
+ {
+ kstd::vector<uint8_t> buffer(512);
+ auto bytes_written = inode.write(buffer.data(), 0, buffer.size());
+
+ THEN("no bytes are written")
+ {
+ REQUIRE(bytes_written == 0);
+ }
+ }
+ }
+}
diff --git a/kernel/src/filesystem/device_inode.cpp b/kernel/src/filesystem/device_inode.cpp
new file mode 100644
index 0000000..81a784c
--- /dev/null
+++ b/kernel/src/filesystem/device_inode.cpp
@@ -0,0 +1,57 @@
+#include <kernel/filesystem/device_inode.hpp>
+
+#include <kernel/devices/block_device_utils.hpp>
+
+#include <kapi/devices/device.hpp>
+#include <kapi/system.hpp>
+
+#include <kstd/memory>
+
+#include <cstddef>
+
+namespace kernel::filesystem
+{
+ device_inode::device_inode(kstd::shared_ptr<kapi::devices::device> const & device)
+ : m_device(device)
+ {
+ if (!device)
+ {
+ kapi::system::panic("[FILESYSTEM] device_inode constructed with null device.");
+ }
+ }
+
+ auto device_inode::read(void * buffer, size_t offset, size_t size) const -> size_t
+ {
+ if (m_device->is_block_device())
+ {
+ return devices::block_device_utils::read(m_device, buffer, offset, size);
+ }
+ else
+ {
+ kapi::system::panic("[FILESYSTEM] device_file::read called on non-block device.");
+ }
+ }
+
+ auto device_inode::write(void const * buffer, size_t offset, size_t size) -> size_t
+ {
+ if (m_device->is_block_device())
+ {
+ return devices::block_device_utils::write(m_device, buffer, offset, size);
+ }
+ else
+ {
+ kapi::system::panic("[FILESYSTEM] device_file::write called on non-block device.");
+ }
+ }
+
+ auto device_inode::device() const -> kstd::shared_ptr<kapi::devices::device> const &
+ {
+ return m_device;
+ }
+
+ auto device_inode::is_device() const -> bool
+ {
+ return true;
+ }
+
+} // namespace kernel::filesystem \ No newline at end of file
diff --git a/kernel/src/filesystem/device_inode.tests.cpp b/kernel/src/filesystem/device_inode.tests.cpp
new file mode 100644
index 0000000..025a22a
--- /dev/null
+++ b/kernel/src/filesystem/device_inode.tests.cpp
@@ -0,0 +1,109 @@
+#include <kernel/filesystem/device_inode.hpp>
+
+#include <kernel/test_support/cpu.hpp>
+#include <kernel/test_support/devices/block_device.hpp>
+#include <kernel/test_support/devices/character_device.hpp>
+
+#include <kstd/memory>
+#include <kstd/print>
+#include <kstd/vector>
+
+#include <catch2/catch_test_macros.hpp>
+
+#include <cstddef>
+#include <cstdint>
+
+SCENARIO("Device inode construction", "[filesystem][device_inode]")
+{
+ GIVEN("a block device")
+ {
+ auto device = kstd::make_shared<kernel::tests::devices::block_device>(0, 0, "test_block_device", 512, 3 * 512);
+
+ WHEN("constructing a device inode with the block device")
+ {
+ auto inode = kernel::filesystem::device_inode{device};
+
+ THEN("the device inode has the correct device")
+ {
+ REQUIRE(inode.device() == device);
+ }
+
+ THEN("the device inode has the correct kind")
+ {
+ REQUIRE(inode.is_device());
+ REQUIRE_FALSE(inode.is_directory());
+ REQUIRE_FALSE(inode.is_regular());
+ REQUIRE_FALSE(inode.is_symbolic_link());
+ }
+ }
+
+ WHEN("constructing a device inode with a null device")
+ {
+ THEN("the constructor panics")
+ {
+ REQUIRE_THROWS_AS((kernel::filesystem::device_inode{nullptr}), kernel::tests::cpu::halt);
+ }
+ }
+ }
+}
+
+SCENARIO("Device inode read/write", "[filesystem][device_inode]")
+{
+ GIVEN("a block device and a device inode for that device")
+ {
+ auto device = kstd::make_shared<kernel::tests::devices::block_device>(0, 0, "test_block_device", 512, 3 * 512);
+ auto inode = kernel::filesystem::device_inode{device};
+
+ WHEN("writing to the device inode")
+ {
+ kstd::vector<uint8_t> write_buffer(1024);
+ for (size_t i = 0; i < write_buffer.size(); ++i)
+ {
+ write_buffer[i] = static_cast<uint8_t>(i % 256);
+ }
+
+ auto bytes_written = inode.write(write_buffer.data(), 256, write_buffer.size());
+
+ THEN("the correct number of bytes is written")
+ {
+ REQUIRE(bytes_written == 1024);
+ }
+
+ THEN("the data written matches the data read back from the device inode")
+ {
+ kstd::vector<uint8_t> read_buffer(1024);
+ auto bytes_read = inode.read(read_buffer.data(), 256, read_buffer.size());
+
+ REQUIRE(bytes_read == write_buffer.size());
+ REQUIRE(read_buffer == write_buffer);
+ }
+ }
+ }
+}
+
+SCENARIO("Device inode read/write with a non-block device", "[filesystem][device_inode]")
+{
+ GIVEN("a non-block device and a device inode for that device")
+ {
+ auto device = kstd::make_shared<kernel::tests::devices::character_device>(0, 0, "test_character_device");
+ auto inode = kernel::filesystem::device_inode{device};
+
+ WHEN("reading from the device inode")
+ {
+ kstd::vector<uint8_t> read_buffer(512);
+ THEN("the system panics")
+ {
+ REQUIRE_THROWS_AS(inode.read(read_buffer.data(), 0, read_buffer.size()), kernel::tests::cpu::halt);
+ }
+ }
+
+ WHEN("writing to the device inode")
+ {
+ kstd::vector<uint8_t> write_buffer(512);
+ THEN("the system panics")
+ {
+ REQUIRE_THROWS_AS(inode.write(write_buffer.data(), 0, write_buffer.size()), kernel::tests::cpu::halt);
+ }
+ }
+ }
+}
diff --git a/kernel/src/filesystem/ext2/filesystem.cpp b/kernel/src/filesystem/ext2/filesystem.cpp
new file mode 100644
index 0000000..3180a19
--- /dev/null
+++ b/kernel/src/filesystem/ext2/filesystem.cpp
@@ -0,0 +1,247 @@
+#include <kernel/filesystem/ext2/filesystem.hpp>
+
+#include <kernel/filesystem/ext2/block_group_descriptor.hpp>
+#include <kernel/filesystem/ext2/inode.hpp>
+#include <kernel/filesystem/ext2/linked_directory_entry.hpp>
+#include <kernel/filesystem/ext2/superblock.hpp>
+#include <kernel/filesystem/filesystem.hpp>
+#include <kernel/filesystem/inode.hpp>
+#include <kernel/filesystem/type.hpp>
+
+#include <kstd/memory>
+#include <kstd/unikstd.h>
+#include <kstd/vector>
+
+#include <array>
+#include <cstddef>
+#include <cstdint>
+#include <string_view>
+
+namespace kernel::filesystem::ext2
+{
+
+ struct type final : kernel::filesystem::type
+ {
+ [[nodiscard]] auto name() const noexcept -> std::string_view override
+ {
+ return "ext2";
+ }
+
+ [[nodiscard]] auto requires_device() const noexcept -> bool override
+ {
+ return true;
+ }
+
+ [[nodiscard]] auto make_instance() const -> kstd::shared_ptr<kernel::filesystem::filesystem> override
+ {
+ return kstd::make_shared<filesystem>();
+ }
+ };
+
+ [[gnu::used]]
+ constexpr auto registration = type_registration<type>{};
+
+ auto filesystem::mount(kstd::shared_ptr<kernel::filesystem::inode> const & backing_inode) -> operation_result
+ {
+ kernel::filesystem::filesystem::mount(backing_inode);
+
+ m_backing_inode->read(&m_superblock, constants::superblock_offset, sizeof(m_superblock));
+
+ if (m_superblock.magic != constants::magic_number)
+ {
+ return operation_result::invalid_magic_number;
+ }
+
+ auto const blocks_per_group = m_superblock.blocks_per_group;
+ auto const num_block_groups = (m_superblock.blocks_count + blocks_per_group - 1) / blocks_per_group;
+
+ m_block_group_descriptors = kstd::vector<block_group_descriptor>(num_block_groups);
+
+ m_backing_inode->read(m_block_group_descriptors.data(), block_group_descriptor_table_offset(),
+ num_block_groups * sizeof(block_group_descriptor));
+
+ m_root_inode = read_inode(constants::root_inode_number);
+
+ if (!m_root_inode || !m_root_inode->is_directory())
+ {
+ return operation_result::invalid_root_inode;
+ }
+ return operation_result::success;
+ }
+
+ auto filesystem::lookup(kstd::shared_ptr<kernel::filesystem::inode> const & parent, std::string_view name) const
+ -> kstd::shared_ptr<kernel::filesystem::inode>
+ {
+ if (!parent || !parent->is_directory())
+ {
+ return nullptr;
+ }
+
+ auto * ext2_parent = static_cast<inode *>(parent.get());
+ if (!ext2_parent)
+ {
+ return nullptr;
+ }
+
+ auto const & inode_data = ext2_parent->data();
+ kstd::vector<uint8_t> buffer(block_size());
+
+ for (uint32_t i = 0; i < inode_block_count(inode_data); ++i)
+ {
+ auto const global_block_number = map_inode_block_index_to_global_block_number(i, inode_data);
+ auto const block_offset = global_block_number * block_size();
+ m_backing_inode->read(buffer.data(), block_offset, block_size());
+
+ auto const * entry = reinterpret_cast<linked_directory_entry const *>(buffer.data());
+ auto bytes_read = 0uz;
+
+ while (bytes_read < block_size() && entry->inode != 0)
+ {
+ auto const entry_name = std::string_view{entry->name.data(), entry->name_len};
+ if (entry_name == name)
+ {
+ return read_inode(entry->inode);
+ }
+
+ bytes_read += entry->rec_len;
+ entry = reinterpret_cast<linked_directory_entry const *>(buffer.data() + bytes_read);
+ }
+ }
+
+ return nullptr;
+ }
+
+ auto filesystem::read_inode(uint32_t inode_number) const -> kstd::shared_ptr<inode>
+ {
+ auto const inodes_per_group = m_superblock.inodes_per_group;
+ auto const block_group_index = (inode_number - 1) / inodes_per_group;
+ auto const inode_index_within_group = (inode_number - 1) % inodes_per_group;
+
+ if (block_group_index >= m_block_group_descriptors.size())
+ {
+ return nullptr;
+ }
+
+ auto const & block_group_descriptor = m_block_group_descriptors.at(block_group_index);
+ auto const inode_table_start_block = block_group_descriptor.inode_table;
+ auto const inode_table_offset = static_cast<size_t>(inode_table_start_block) * block_size();
+ auto const inode_offset = inode_table_offset + inode_index_within_group * inode_size();
+
+ auto new_inode_data = inode_data{};
+ m_backing_inode->read(&new_inode_data, inode_offset, sizeof(inode_data));
+
+ return kstd::make_shared<inode>(this, new_inode_data);
+ }
+
+ auto filesystem::indirect_levels() const -> std::array<indirect_level, 3>
+ {
+ return {
+ {{constants::singly_indirect_block_index, block_numbers_per_singly_indirect_block()},
+ {constants::doubly_indirect_block_index, block_numbers_per_doubly_indirect_block()},
+ {constants::triply_indirect_block_index, block_numbers_per_triply_indirect_block()}}
+ };
+ }
+
+ auto filesystem::map_inode_block_index_to_global_block_number(size_t inode_block_index, inode_data data) const
+ -> kstd::ssize_t
+ {
+ if (inode_block_index < constants::direct_block_count)
+ {
+ return data.block.at(inode_block_index);
+ }
+
+ inode_block_index -= constants::direct_block_count;
+
+ for (auto const & level : indirect_levels())
+ {
+ if (inode_block_index >= level.capacity)
+ {
+ inode_block_index -= level.capacity;
+ continue;
+ }
+
+ auto block_number = data.block[level.slot_index];
+ if (block_number == 0)
+ {
+ return 0;
+ }
+
+ for (auto stride = level.capacity / block_numbers_per_block();; stride /= block_numbers_per_block())
+ {
+ auto const idx = inode_block_index / stride;
+ inode_block_index %= stride;
+
+ block_number = read_block_number_at_index(block_number, idx);
+ if (block_number == 0)
+ {
+ return 0;
+ }
+
+ if (stride == 1)
+ {
+ break;
+ }
+ }
+
+ return block_number;
+ }
+
+ return -1;
+ }
+
+ auto filesystem::read_block_number_at_index(uint32_t block_number, size_t index) const -> uint32_t
+ {
+ uint32_t block_number_buffer = 0;
+
+ auto const block_start_offset = block_number * block_size();
+ auto const number_start_address = block_start_offset + index * sizeof(uint32_t);
+ m_backing_inode->read(&block_number_buffer, number_start_address, sizeof(uint32_t));
+
+ return block_number_buffer;
+ }
+
+ auto filesystem::block_numbers_per_block() const -> size_t
+ {
+ return block_size() / sizeof(uint32_t);
+ }
+
+ auto filesystem::block_numbers_per_singly_indirect_block() const -> size_t
+ {
+ return block_numbers_per_block();
+ }
+
+ auto filesystem::block_numbers_per_doubly_indirect_block() const -> size_t
+ {
+ return block_numbers_per_singly_indirect_block() * block_numbers_per_block();
+ }
+
+ auto filesystem::block_numbers_per_triply_indirect_block() const -> size_t
+ {
+ return block_numbers_per_doubly_indirect_block() * block_numbers_per_block();
+ }
+
+ auto filesystem::block_size() const -> size_t
+ {
+ return constants::base_block_size << m_superblock.log_block_size;
+ }
+
+ auto filesystem::revision_level() const -> uint32_t
+ {
+ return m_superblock.rev_level;
+ }
+
+ auto filesystem::inode_size() const -> uint16_t
+ {
+ return revision_level() == constants::good_old_revision ? 128 : m_superblock.inode_size;
+ }
+
+ auto filesystem::inode_block_count(inode_data const & data) const -> uint32_t
+ {
+ return data.blocks / (2 << m_superblock.log_block_size);
+ }
+
+ auto filesystem::block_group_descriptor_table_offset() const -> size_t
+ {
+ return block_size() == 1024 ? 2 * block_size() : block_size();
+ }
+} // namespace kernel::filesystem::ext2
diff --git a/kernel/src/filesystem/ext2/filesystem.tests.cpp b/kernel/src/filesystem/ext2/filesystem.tests.cpp
new file mode 100644
index 0000000..8341070
--- /dev/null
+++ b/kernel/src/filesystem/ext2/filesystem.tests.cpp
@@ -0,0 +1,139 @@
+#include <kernel/filesystem/ext2/filesystem.hpp>
+
+#include <kernel/devices/storage/management.hpp>
+#include <kernel/filesystem/device_inode.hpp>
+#include <kernel/filesystem/ext2/inode.hpp>
+#include <kernel/filesystem/filesystem.hpp>
+#include <kernel/test_support/devices/block_device.hpp>
+#include <kernel/test_support/filesystem/ext2.hpp>
+#include <kernel/test_support/filesystem/storage_boot_module_fixture.hpp>
+
+#include <kstd/memory>
+#include <kstd/vector>
+
+#include <catch2/catch_test_macros.hpp>
+
+#include <array>
+#include <cstdint>
+#include <filesystem>
+
+SCENARIO_METHOD(kernel::tests::filesystem::storage_boot_module_fixture,
+ "Ext2 filesystem mount and lookup with real image", "[filesystem][ext2][filesystem][img]")
+{
+ auto const image_path = std::filesystem::path{KERNEL_TEST_ASSETS_DIR} / "ext2_1KB_fs.img";
+
+ GIVEN("a mounted ext2 filesystem from a real image")
+ {
+ REQUIRE(std::filesystem::exists(image_path));
+ REQUIRE_NOTHROW(setup_modules_from_img({"test_img_module"}, {image_path}));
+
+ auto boot_device = kernel::devices::storage::management::get().determine_boot_device();
+ REQUIRE(boot_device != nullptr);
+
+ auto dev_inode = kstd::make_shared<kernel::filesystem::device_inode>(boot_device);
+
+ auto fs = kernel::filesystem::ext2::filesystem{};
+ REQUIRE(fs.mount(dev_inode) == kernel::filesystem::filesystem::operation_result::success);
+
+ THEN("the root inode is available and is a directory")
+ {
+ REQUIRE(fs.root_inode() != nullptr);
+ REQUIRE(fs.root_inode()->is_directory());
+ }
+
+ THEN("lookup resolves known entries from the image")
+ {
+ auto information = fs.lookup(fs.root_inode(), "information");
+ REQUIRE(information != nullptr);
+ REQUIRE(information->is_directory());
+
+ auto info_1 = fs.lookup(information, "info_1.txt");
+ REQUIRE(info_1 != nullptr);
+ REQUIRE(info_1->is_regular());
+ }
+
+ THEN("lookup returns null for invalid inputs")
+ {
+ REQUIRE(fs.lookup(nullptr, "information") == nullptr);
+
+ auto information = fs.lookup(fs.root_inode(), "information");
+ REQUIRE(information != nullptr);
+ auto info_1 = fs.lookup(information, "info_1.txt");
+ REQUIRE(info_1 != nullptr);
+
+ REQUIRE(fs.lookup(info_1, "anything") == nullptr);
+ REQUIRE(fs.lookup(fs.root_inode(), "does_not_exist") == nullptr);
+ }
+ }
+}
+
+SCENARIO("Ext2 filesystem rejects invalid magic", "[filesystem][ext2][filesystem]")
+{
+ auto const block_size = 1024;
+ GIVEN("a block device that does not contain an ext2 superblock")
+ {
+ auto device = kstd::make_shared<kernel::tests::devices::block_device>(0, 0, "mock", block_size, 2 * block_size);
+ REQUIRE(device != nullptr);
+
+ auto dev_inode = kstd::make_shared<kernel::filesystem::device_inode>(device);
+
+ auto fs = kernel::filesystem::ext2::filesystem{};
+
+ THEN("mount fails with invalid_magic_number")
+ {
+ REQUIRE(fs.mount(dev_inode) == kernel::filesystem::filesystem::operation_result::invalid_magic_number);
+ }
+ }
+}
+
+SCENARIO("Ext2 block mapping includes direct and all indirect levels", "[filesystem][ext2][filesystem]")
+{
+ auto const block_size = 1024;
+
+ GIVEN("a minimally valid ext2 layout with configured indirect block tables")
+ {
+ auto device = kstd::make_shared<kernel::tests::devices::block_device>(0, 0, "mock", block_size, 128 * block_size);
+ REQUIRE(device != nullptr);
+
+ kernel::tests::filesystem::ext2::setup_mock_ext2_layout(*device);
+
+ auto dev_inode = kstd::make_shared<kernel::filesystem::device_inode>(device);
+
+ auto fs = kernel::filesystem::ext2::filesystem{};
+ REQUIRE(fs.mount(dev_inode) == kernel::filesystem::filesystem::operation_result::success);
+
+ auto inode_data = kernel::filesystem::ext2::inode_data{};
+ inode_data.block[0] = 7;
+
+ inode_data.block[12] = 30;
+ kernel::tests::filesystem::ext2::write_u32(*device, 30 * block_size, 31);
+
+ inode_data.block[13] = 40;
+ kernel::tests::filesystem::ext2::write_u32(*device, 40 * block_size, 41);
+ kernel::tests::filesystem::ext2::write_u32(*device, 41 * block_size, 42);
+
+ inode_data.block[14] = 50;
+ kernel::tests::filesystem::ext2::write_u32(*device, 50 * block_size, 51);
+ kernel::tests::filesystem::ext2::write_u32(*device, 51 * block_size, 52);
+ kernel::tests::filesystem::ext2::write_u32(*device, 52 * block_size, 53);
+
+ auto const numbers_per_block = static_cast<uint32_t>(block_size / sizeof(uint32_t));
+ auto const singly_start = static_cast<uint32_t>(kernel::filesystem::ext2::constants::direct_block_count);
+ auto const doubly_start = singly_start + numbers_per_block;
+ auto const triply_start = doubly_start + numbers_per_block * numbers_per_block;
+
+ THEN("mapping resolves direct, singly, doubly and triply indirect indexes")
+ {
+ REQUIRE(fs.map_inode_block_index_to_global_block_number(0, inode_data) == 7);
+ REQUIRE(fs.map_inode_block_index_to_global_block_number(singly_start, inode_data) == 31);
+ REQUIRE(fs.map_inode_block_index_to_global_block_number(doubly_start, inode_data) == 42);
+ REQUIRE(fs.map_inode_block_index_to_global_block_number(triply_start, inode_data) == 53);
+ }
+
+ THEN("mapping returns zero for out-of-range indexes")
+ {
+ auto const beyond_triply = triply_start + numbers_per_block * numbers_per_block * numbers_per_block;
+ REQUIRE(fs.map_inode_block_index_to_global_block_number(beyond_triply, inode_data) == -1);
+ }
+ }
+}
diff --git a/kernel/src/filesystem/ext2/inode.cpp b/kernel/src/filesystem/ext2/inode.cpp
new file mode 100644
index 0000000..35a32ee
--- /dev/null
+++ b/kernel/src/filesystem/ext2/inode.cpp
@@ -0,0 +1,111 @@
+#include <kernel/filesystem/ext2/inode.hpp>
+
+#include <kernel/filesystem/ext2/filesystem.hpp>
+#include <kernel/filesystem/inode.hpp>
+
+#include <kapi/system.hpp>
+
+#include <kstd/cstring>
+
+#include <algorithm>
+#include <cstddef>
+#include <cstdint>
+
+namespace kernel::filesystem::ext2
+{
+ inode::inode(filesystem const * fs, inode_data const & data)
+ : m_filesystem(fs)
+ , m_data(data)
+ {
+ if (!m_filesystem)
+ {
+ kapi::system::panic("[EXT2] ext2::inode constructed with filesystem null pointer");
+ }
+ }
+
+ auto inode::read(void * buffer, size_t offset, size_t size) const -> size_t
+ {
+ auto const max_readable = this->size() - offset;
+ auto const requested_size = std::min(size, max_readable);
+
+ if (is_symbolic_link() && this->size() <= sizeof(m_data.block))
+ {
+ auto inline_target = reinterpret_cast<uint8_t const *>(m_data.block.data());
+ kstd::libc::memcpy(static_cast<uint8_t *>(buffer), inline_target + offset, requested_size);
+ return requested_size;
+ }
+
+ auto block_index = offset / m_filesystem->block_size();
+ auto in_block_offset = offset % m_filesystem->block_size();
+
+ auto bytes_read = 0uz;
+
+ while (bytes_read < requested_size)
+ {
+ auto const block_number = m_filesystem->map_inode_block_index_to_global_block_number(block_index, m_data);
+ if (block_number == -1)
+ {
+ break;
+ }
+
+ auto const bytes_to_read = std::min(requested_size - bytes_read, m_filesystem->block_size() - in_block_offset);
+ if (block_number == 0)
+ {
+ kstd::libc::memset(static_cast<uint8_t *>(buffer) + bytes_read, 0, bytes_to_read);
+ bytes_read += bytes_to_read;
+ }
+ else
+ {
+ auto const block_start_offset = block_number * m_filesystem->block_size();
+ auto const read_offset = block_start_offset + in_block_offset;
+
+ bytes_read += m_filesystem->backing_inode()->read(static_cast<uint8_t *>(buffer) + bytes_read, read_offset,
+ bytes_to_read);
+ }
+
+ block_index++;
+ in_block_offset = 0; // After the first block, we always start at the beginning of the block
+ }
+
+ return bytes_read;
+ }
+
+ auto inode::write(void const *, size_t, size_t) -> size_t
+ {
+ kapi::system::panic("[EXT2] inode::write is not implemented yet");
+ return 0;
+ }
+
+ [[nodiscard]] auto inode::data() const -> inode_data const &
+ {
+ return m_data;
+ }
+
+ auto inode::is_regular() const -> bool
+ {
+ return (m_data.mode & constants::mode_mask) == constants::mode_regular;
+ }
+
+ auto inode::is_directory() const -> bool
+ {
+ return (m_data.mode & constants::mode_mask) == constants::mode_directory;
+ }
+
+ auto inode::is_symbolic_link() const -> bool
+ {
+ return (m_data.mode & constants::mode_mask) == constants::mode_symbolic_link;
+ }
+
+ auto inode::size() const -> uint64_t
+ {
+ uint64_t size = m_data.size;
+
+ if (m_filesystem->revision_level() > constants::good_old_revision && is_regular())
+ {
+ size |= static_cast<uint64_t>(m_data.dir_acl) << 32;
+ }
+
+ return size;
+ }
+
+} // namespace kernel::filesystem::ext2
diff --git a/kernel/src/filesystem/ext2/inode.tests.cpp b/kernel/src/filesystem/ext2/inode.tests.cpp
new file mode 100644
index 0000000..4aecc04
--- /dev/null
+++ b/kernel/src/filesystem/ext2/inode.tests.cpp
@@ -0,0 +1,376 @@
+#include <kernel/filesystem/ext2/inode.hpp>
+
+#include <kernel/devices/storage/management.hpp>
+#include <kernel/filesystem/device_inode.hpp>
+#include <kernel/filesystem/ext2/filesystem.hpp>
+#include <kernel/filesystem/ext2/superblock.hpp>
+#include <kernel/filesystem/filesystem.hpp>
+#include <kernel/test_support/cpu.hpp>
+#include <kernel/test_support/devices/block_device.hpp>
+#include <kernel/test_support/filesystem/ext2.hpp>
+#include <kernel/test_support/filesystem/storage_boot_module_fixture.hpp>
+
+#include <kstd/memory>
+#include <kstd/vector>
+
+#include <catch2/catch_test_macros.hpp>
+
+#include <algorithm>
+#include <cstddef>
+#include <filesystem>
+#include <string_view>
+
+SCENARIO("Ext2 inode initialization and properties", "[filesystem][ext2][inode]")
+{
+ GIVEN("an ext2 filesystem")
+ {
+ auto fs = kernel::filesystem::ext2::filesystem{};
+ auto data = kernel::filesystem::ext2::inode_data{};
+
+ THEN("the inode is initialized with regular file mode in data and has the kind regular")
+ {
+ data.mode = kernel::filesystem::ext2::constants::mode_regular;
+ auto inode = kernel::filesystem::ext2::inode(&fs, data);
+
+ REQUIRE(inode.is_regular());
+ REQUIRE_FALSE(inode.is_directory());
+ REQUIRE_FALSE(inode.is_device());
+ REQUIRE_FALSE(inode.is_symbolic_link());
+ }
+
+ THEN("the inode is initialized with directory mode in data and has the kind directory")
+ {
+ data.mode = kernel::filesystem::ext2::constants::mode_directory;
+ auto inode = kernel::filesystem::ext2::inode(&fs, data);
+
+ REQUIRE_FALSE(inode.is_regular());
+ REQUIRE(inode.is_directory());
+ REQUIRE_FALSE(inode.is_device());
+ REQUIRE_FALSE(inode.is_symbolic_link());
+ }
+
+ THEN("the inode is initialized with symbolic link mode in data and has the kind symbolic link")
+ {
+ data.mode = kernel::filesystem::ext2::constants::mode_symbolic_link;
+ auto inode = kernel::filesystem::ext2::inode(&fs, data);
+
+ REQUIRE_FALSE(inode.is_regular());
+ REQUIRE_FALSE(inode.is_directory());
+ REQUIRE_FALSE(inode.is_device());
+ REQUIRE(inode.is_symbolic_link());
+ }
+
+ THEN("the inode is initialized with zero mode in data and has no specific kind")
+ {
+ data.mode = 0;
+ auto inode = kernel::filesystem::ext2::inode(&fs, data);
+
+ REQUIRE_FALSE(inode.is_regular());
+ REQUIRE_FALSE(inode.is_directory());
+ REQUIRE_FALSE(inode.is_device());
+ REQUIRE_FALSE(inode.is_symbolic_link());
+ }
+ }
+
+ GIVEN("no filesystem (null pointer)")
+ {
+ THEN("constructing an inode with a null filesystem pointer panics")
+ {
+ REQUIRE_THROWS_AS(kernel::filesystem::ext2::inode(nullptr, {}), kernel::tests::cpu::halt);
+ }
+ }
+}
+
+SCENARIO_METHOD(kernel::tests::filesystem::storage_boot_module_fixture, "Ext2 inode reads from real image",
+ "[filesystem][ext2][inode][img]")
+{
+ auto const image_path = std::filesystem::path{KERNEL_TEST_ASSETS_DIR} / "ext2_1KB_fs.img";
+
+ GIVEN("a mounted ext2 filesystem and a regular file inode")
+ {
+ REQUIRE(std::filesystem::exists(image_path));
+ REQUIRE_NOTHROW(setup_modules_from_img({"test_img_module"}, {image_path}));
+
+ auto boot_device = kernel::devices::storage::management::get().determine_boot_device();
+ REQUIRE(boot_device != nullptr);
+
+ auto dev_inode = kstd::make_shared<kernel::filesystem::device_inode>(boot_device);
+
+ auto fs = kernel::filesystem::ext2::filesystem{};
+ REQUIRE(fs.mount(dev_inode) == kernel::filesystem::filesystem::operation_result::success);
+
+ auto information = fs.lookup(fs.root_inode(), "information");
+ REQUIRE(information != nullptr);
+ auto file = fs.lookup(information, "info_1.txt");
+ REQUIRE(file != nullptr);
+ REQUIRE(file->is_regular());
+
+ THEN("reading from offset zero returns expected file prefix")
+ {
+ auto buffer = kstd::vector<std::byte>(6);
+ auto const bytes_read = file->read(buffer.data(), 0, buffer.size());
+
+ REQUIRE(bytes_read == 6);
+
+ auto const text = std::string_view{reinterpret_cast<char const *>(buffer.data()), bytes_read};
+ REQUIRE(text == "info_1");
+ }
+
+ THEN("reading with an offset returns the expected byte")
+ {
+ auto buffer = kstd::vector<std::byte>(1);
+ auto const bytes_read = file->read(buffer.data(), 5, buffer.size());
+
+ REQUIRE(bytes_read == 1);
+ REQUIRE(static_cast<char>(buffer[0]) == '1');
+ }
+ }
+}
+
+SCENARIO("Ext2 inode handles zeros in block mappings as file holes", "[filesystem][ext2][inode]")
+{
+ auto const block_size = 1024uz;
+ GIVEN("an ext2 inode with only direct mapped data blocks")
+ {
+ auto device = kstd::make_shared<kernel::tests::devices::block_device>(0, 0, "mock", block_size, 64 * block_size);
+ REQUIRE(device != nullptr);
+ kernel::tests::filesystem::ext2::setup_mock_ext2_layout(*device);
+
+ auto dev_inode = kstd::make_shared<kernel::filesystem::device_inode>(device);
+
+ auto fs = kernel::filesystem::ext2::filesystem{};
+ REQUIRE(fs.mount(dev_inode) == kernel::filesystem::filesystem::operation_result::success);
+
+ auto data = kernel::filesystem::ext2::inode_data{};
+ data.block[0] = 30;
+ data.block[1] = 0;
+ data.block[2] = 31;
+ data.size = block_size * 3;
+
+ kernel::tests::filesystem::ext2::write_bytes(*device, 30 * block_size, "Hello", 5);
+ kernel::tests::filesystem::ext2::write_bytes(*device, 31 * block_size, "World!", 6);
+
+ auto inode = kernel::filesystem::ext2::inode{&fs, data};
+
+ auto buffer = kstd::vector<std::byte>(data.size, std::byte{0xAB});
+
+ THEN("correct number of bytes are read and holes are returned as zeros")
+ {
+ auto const bytes_read = inode.read(buffer.data(), 0, buffer.size());
+ REQUIRE(bytes_read == data.size);
+
+ auto const text = std::string_view{reinterpret_cast<char const *>(buffer.data()), bytes_read};
+ REQUIRE(text.substr(0, 5) == "Hello");
+ REQUIRE(std::ranges::all_of(text.substr(5, block_size - 5), [](char c) { return c == '\0'; }));
+ REQUIRE(text.substr(2 * block_size, 6) == "World!");
+ REQUIRE(std::ranges::all_of(text.substr(2 * block_size + 6, 3 * block_size), [](char c) { return c == '\0'; }));
+ }
+ }
+
+ GIVEN("an ext2 indode with file holes in singly indirect blocks")
+ {
+ auto device = kstd::make_shared<kernel::tests::devices::block_device>(0, 0, "mock", block_size, 64 * block_size);
+ REQUIRE(device != nullptr);
+ kernel::tests::filesystem::ext2::setup_mock_ext2_layout(*device);
+
+ auto dev_inode = kstd::make_shared<kernel::filesystem::device_inode>(device);
+
+ auto fs = kernel::filesystem::ext2::filesystem{};
+ REQUIRE(fs.mount(dev_inode) == kernel::filesystem::filesystem::operation_result::success);
+
+ auto data = kernel::filesystem::ext2::inode_data{};
+ data.block[0] = 30;
+ data.block[12] = 31;
+ data.size = block_size * 15;
+
+ kernel::tests::filesystem::ext2::write_u32(*device, 31 * block_size, 50);
+ kernel::tests::filesystem::ext2::write_u32(*device, 31 * block_size + 4, 0);
+ kernel::tests::filesystem::ext2::write_u32(*device, 31 * block_size + 8, 51);
+
+ kernel::tests::filesystem::ext2::write_bytes(*device, 30 * block_size, "Hello", 5);
+ kernel::tests::filesystem::ext2::write_bytes(*device, 50 * block_size, "Blub", 4);
+ kernel::tests::filesystem::ext2::write_bytes(*device, 51 * block_size, "World!", 6);
+
+ auto inode = kernel::filesystem::ext2::inode{&fs, data};
+
+ auto buffer = kstd::vector<std::byte>(data.size, std::byte{0xAB});
+
+ THEN("correct number of bytes are read and holes are returned as zeros")
+ {
+ auto const bytes_read = inode.read(buffer.data(), 0, buffer.size());
+ REQUIRE(bytes_read == data.size);
+
+ auto const text = std::string_view{reinterpret_cast<char const *>(buffer.data()), bytes_read};
+ REQUIRE(text.substr(0, 5) == "Hello");
+ REQUIRE(std::ranges::all_of(text.substr(5, 12 * block_size - 5), [](char c) { return c == '\0'; }));
+ REQUIRE(text.substr(12 * block_size, 4) == "Blub");
+ REQUIRE(
+ std::ranges::all_of(text.substr(12 * block_size + 4, 2 * block_size - 4), [](char c) { return c == '\0'; }));
+ REQUIRE(text.substr(14 * block_size, 6) == "World!");
+ REQUIRE(
+ std::ranges::all_of(text.substr(14 * block_size + 6, 1 * block_size - 6), [](char c) { return c == '\0'; }));
+ }
+ }
+
+ GIVEN("an ext2 inode with zero singly indirect block pointer")
+ {
+ auto device = kstd::make_shared<kernel::tests::devices::block_device>(0, 0, "mock", block_size, 64 * block_size);
+ REQUIRE(device != nullptr);
+ kernel::tests::filesystem::ext2::setup_mock_ext2_layout(*device);
+
+ auto dev_inode = kstd::make_shared<kernel::filesystem::device_inode>(device);
+
+ auto fs = kernel::filesystem::ext2::filesystem{};
+ REQUIRE(fs.mount(dev_inode) == kernel::filesystem::filesystem::operation_result::success);
+
+ auto data = kernel::filesystem::ext2::inode_data{};
+ data.block[12] = 0;
+ data.size = block_size * 15;
+
+ auto inode = kernel::filesystem::ext2::inode{&fs, data};
+
+ auto buffer = kstd::vector<std::byte>(block_size * 15, std::byte{0xAB});
+
+ THEN("all direct blocks are zero when singly indirect block pointer is zero")
+ {
+ auto const bytes_read = inode.read(buffer.data(), 0, buffer.size());
+ REQUIRE(bytes_read == buffer.size());
+ REQUIRE(std::ranges::all_of(buffer, [](std::byte c) { return c == std::byte{0x00}; }));
+ }
+ }
+}
+
+SCENARIO("Ext2 inode read across block boundaries", "[filesystem][ext2][inode]")
+{
+ auto const block_size = 1024uz;
+ GIVEN("an ext2 inode with two direct blocks and a block size of 1024 bytes")
+ {
+ auto device = kstd::make_shared<kernel::tests::devices::block_device>(0, 0, "mock", block_size, 64 * block_size);
+ REQUIRE(device != nullptr);
+ kernel::tests::filesystem::ext2::setup_mock_ext2_layout(*device);
+
+ auto dev_inode = kstd::make_shared<kernel::filesystem::device_inode>(device);
+
+ auto fs = kernel::filesystem::ext2::filesystem{};
+ REQUIRE(fs.mount(dev_inode) == kernel::filesystem::filesystem::operation_result::success);
+
+ auto inode_data = kernel::filesystem::ext2::inode_data{};
+ inode_data.size = block_size * 2;
+ inode_data.block[0] = 20;
+ kernel::tests::filesystem::ext2::write_bytes(*device, 21 * block_size - 6, "Hello ", 6);
+ inode_data.block[1] = 21;
+ kernel::tests::filesystem::ext2::write_bytes(*device, 21 * block_size, "World!", 6);
+ auto inode = kernel::filesystem::ext2::inode{&fs, inode_data};
+
+ auto buffer = kstd::vector<std::byte>(12, std::byte{0x00});
+
+ THEN("reading across the block boundary returns the combined content")
+ {
+ auto const bytes_read = inode.read(buffer.data(), block_size - 6, buffer.size());
+ REQUIRE(bytes_read == 12);
+
+ auto const text = std::string_view{reinterpret_cast<char const *>(buffer.data()), bytes_read};
+ REQUIRE(text == "Hello World!");
+ }
+ }
+}
+
+SCENARIO("Ext2 inode write is not implemented", "[filesystem][ext2][inode]")
+{
+ GIVEN("an ext2 inode")
+ {
+ auto fs = kernel::filesystem::ext2::filesystem{};
+ auto inode = kernel::filesystem::ext2::inode{&fs, kernel::filesystem::ext2::inode_data{}};
+
+ THEN("writing to the inode panics")
+ {
+ auto buffer = kstd::vector<std::byte>(32, std::byte{0x00});
+ REQUIRE_THROWS_AS(inode.write(buffer.data(), 0, buffer.size()), kernel::tests::cpu::halt);
+ }
+ }
+}
+
+SCENARIO("Ext2 inode get_size() correctly returns size depending on revision level", "[filesystem][ext2][inode]")
+{
+ auto const block_size = 1024uz;
+
+ auto superblock = kernel::filesystem::ext2::superblock{};
+ superblock.magic = kernel::filesystem::ext2::constants::magic_number;
+ superblock.log_block_size = 0;
+ superblock.blocks_count = 64;
+ superblock.blocks_per_group = 64;
+ superblock.inodes_per_group = 32;
+ superblock.inode_size = 128;
+
+ GIVEN("an ext2 inode with good old revision and inode_data.size = 256, inode_data.dir_acl = 32")
+ {
+ superblock.rev_level = 0;
+
+ auto device = kstd::make_shared<kernel::tests::devices::block_device>(0, 0, "mock", block_size, 64 * block_size);
+ REQUIRE(device != nullptr);
+ kernel::tests::filesystem::ext2::setup_mock_ext2_layout(*device, superblock);
+
+ auto dev_inode = kstd::make_shared<kernel::filesystem::device_inode>(device);
+
+ auto fs = kernel::filesystem::ext2::filesystem{};
+ REQUIRE(fs.mount(dev_inode) == kernel::filesystem::filesystem::operation_result::success);
+
+ auto data = kernel::filesystem::ext2::inode_data{};
+ data.size = 256;
+ data.dir_acl = 32;
+
+ THEN("the inode size is 256 if mode = regular")
+ {
+ data.mode = kernel::filesystem::ext2::constants::mode_regular;
+
+ auto inode = kernel::filesystem::ext2::inode{&fs, data};
+
+ REQUIRE(inode.size() == 256);
+ }
+
+ THEN("the inode size is 256 if mode = directory")
+ {
+ data.mode = kernel::filesystem::ext2::constants::mode_directory;
+
+ auto inode = kernel::filesystem::ext2::inode{&fs, data};
+
+ REQUIRE(inode.size() == 256);
+ }
+ }
+
+ GIVEN("an ext2 inode with good dynamic revision and inode_data.size = 256, inode_data.dir_acl = 32")
+ {
+ superblock.rev_level = 1;
+
+ auto device = kstd::make_shared<kernel::tests::devices::block_device>(0, 0, "mock", block_size, 64 * block_size);
+ REQUIRE(device != nullptr);
+ kernel::tests::filesystem::ext2::setup_mock_ext2_layout(*device, superblock);
+
+ auto dev_inode = kstd::make_shared<kernel::filesystem::device_inode>(device);
+
+ auto fs = kernel::filesystem::ext2::filesystem{};
+ REQUIRE(fs.mount(dev_inode) == kernel::filesystem::filesystem::operation_result::success);
+
+ auto data = kernel::filesystem::ext2::inode_data{};
+ data.size = 256;
+ data.dir_acl = 32;
+
+ THEN("the inode size is 256 if mode = regular")
+ {
+ data.mode = kernel::filesystem::ext2::constants::mode_regular;
+
+ auto inode = kernel::filesystem::ext2::inode{&fs, data};
+
+ REQUIRE(inode.size() == 0x0000'0020'0000'0100);
+ }
+
+ THEN("the inode size is 256 if mode = directory")
+ {
+ data.mode = kernel::filesystem::ext2::constants::mode_directory;
+
+ auto inode = kernel::filesystem::ext2::inode{&fs, data};
+
+ REQUIRE(inode.size() == 256);
+ }
+ }
+} \ No newline at end of file
diff --git a/kernel/src/filesystem/filesystem.cpp b/kernel/src/filesystem/filesystem.cpp
new file mode 100644
index 0000000..24d0e22
--- /dev/null
+++ b/kernel/src/filesystem/filesystem.cpp
@@ -0,0 +1,60 @@
+#include <kernel/filesystem/filesystem.hpp>
+
+#include <kernel/filesystem/ext2/filesystem.hpp>
+#include <kernel/filesystem/inode.hpp>
+
+#include <kapi/system.hpp>
+
+#include <kstd/memory>
+
+#include <array>
+
+namespace kernel::filesystem
+{
+ namespace
+ {
+ constexpr auto static filesystem_factories = std::array{
+ []() { return kstd::make_shared<ext2::filesystem>(); },
+ };
+ } // namespace
+
+ auto filesystem::probe_and_mount(kstd::shared_ptr<inode> const & backing_inode) -> kstd::shared_ptr<filesystem>
+ {
+ if (!backing_inode)
+ {
+ kapi::system::panic("[FILESYSTEM] cannot mount filesystem: backing inode is null.");
+ }
+
+ for (auto & factory : filesystem_factories)
+ {
+ auto fs = factory();
+ if (fs->mount(backing_inode) == operation_result::success)
+ {
+ return fs;
+ }
+ }
+
+ return nullptr;
+ }
+
+ auto filesystem::mount(kstd::shared_ptr<inode> const & backing_inode) -> operation_result
+ {
+ if (!backing_inode)
+ {
+ kapi::system::panic("[FILESYSTEM] cannot mount filesystem: backing inode is null.");
+ }
+
+ m_backing_inode = backing_inode;
+ return operation_result::success;
+ }
+
+ auto filesystem::root_inode() const -> kstd::shared_ptr<inode> const &
+ {
+ return m_root_inode;
+ }
+
+ auto filesystem::backing_inode() const -> kstd::shared_ptr<inode> const &
+ {
+ return m_backing_inode;
+ }
+} // namespace kernel::filesystem \ No newline at end of file
diff --git a/kernel/src/filesystem/inode.cpp b/kernel/src/filesystem/inode.cpp
new file mode 100644
index 0000000..c188917
--- /dev/null
+++ b/kernel/src/filesystem/inode.cpp
@@ -0,0 +1,24 @@
+#include <kernel/filesystem/inode.hpp>
+
+namespace kernel::filesystem
+{
+ auto inode::is_directory() const -> bool
+ {
+ return false;
+ }
+
+ auto inode::is_regular() const -> bool
+ {
+ return false;
+ }
+
+ auto inode::is_device() const -> bool
+ {
+ return false;
+ }
+
+ auto inode::is_symbolic_link() const -> bool
+ {
+ return false;
+ }
+} // namespace kernel::filesystem \ No newline at end of file
diff --git a/kernel/src/filesystem/mount.cpp b/kernel/src/filesystem/mount.cpp
new file mode 100644
index 0000000..ead7479
--- /dev/null
+++ b/kernel/src/filesystem/mount.cpp
@@ -0,0 +1,90 @@
+#include <kernel/filesystem/mount.hpp>
+
+#include <kernel/filesystem/dentry.hpp>
+#include <kernel/filesystem/filesystem.hpp>
+
+#include <kapi/system.hpp>
+
+#include <kstd/memory>
+#include <kstd/string>
+
+#include <cstddef>
+#include <string_view>
+
+namespace kernel::filesystem
+{
+ mount::mount(kstd::shared_ptr<dentry> const & mount_dentry, kstd::shared_ptr<dentry> const & root_dentry,
+ kstd::shared_ptr<filesystem> const & fs, kstd::shared_ptr<mount> const & parent_mount,
+ kstd::shared_ptr<mount> const & source_mount)
+ : m_mount_dentry(mount_dentry)
+ , m_root_dentry(root_dentry)
+ , m_filesystem(fs)
+ , m_parent_mount(parent_mount)
+ , m_source_mount(source_mount)
+ , m_ref_count(0)
+ {
+ if (!m_filesystem)
+ {
+ kapi::system::panic("[FILESYSTEM] mount initialized with null filesystem.");
+ }
+ }
+
+ auto mount::mount_dentry() const -> kstd::shared_ptr<dentry> const &
+ {
+ return m_mount_dentry;
+ }
+
+ auto mount::get_filesystem() const -> kstd::shared_ptr<filesystem> const &
+ {
+ return m_filesystem;
+ }
+
+ auto mount::root_dentry() const -> kstd::shared_ptr<dentry> const &
+ {
+ return m_root_dentry;
+ }
+
+ auto mount::mount_path() const -> kstd::string
+ {
+ if (m_mount_dentry)
+ {
+ return m_mount_dentry->absolute_path();
+ }
+ return "/";
+ }
+
+ auto mount::parent_mount() const -> kstd::shared_ptr<mount> const &
+ {
+ return m_parent_mount;
+ }
+
+ auto mount::source_mount() const -> kstd::shared_ptr<mount>
+ {
+ return m_source_mount.lock();
+ }
+
+ auto mount::increment_ref_count() -> void
+ {
+ m_ref_count += 1;
+ }
+
+ auto mount::decrement_ref_count() -> void
+ {
+ if (m_ref_count == 0)
+ {
+ kapi::system::panic("[FILESYSTEM] decrement_ref_count() was called but ref_count is 0");
+ }
+
+ m_ref_count -= 1;
+ }
+
+ auto mount::is_ready_to_unmount() const -> bool
+ {
+ return m_ref_count == 0;
+ }
+
+ auto mount::ref_count() const -> size_t
+ {
+ return m_ref_count;
+ }
+} // namespace kernel::filesystem \ No newline at end of file
diff --git a/kernel/src/filesystem/mount.tests.cpp b/kernel/src/filesystem/mount.tests.cpp
new file mode 100644
index 0000000..c9ff82e
--- /dev/null
+++ b/kernel/src/filesystem/mount.tests.cpp
@@ -0,0 +1,94 @@
+#include <kernel/filesystem/mount.hpp>
+
+#include <kernel/filesystem/dentry.hpp>
+#include <kernel/test_support/cpu.hpp>
+#include <kernel/test_support/filesystem/filesystem.hpp>
+#include <kernel/test_support/filesystem/inode.hpp>
+
+#include <kstd/memory>
+#include <kstd/print>
+#include <kstd/vector>
+
+#include <catch2/catch_test_macros.hpp>
+
+#include <stdexcept>
+
+SCENARIO("Mount construction", "[filesystem][mount]")
+{
+ GIVEN("a filesystem and a root dentry")
+ {
+ auto fs = kstd::make_shared<kernel::tests::filesystem::filesystem>();
+ auto root_inode = kstd::make_shared<kernel::tests::filesystem::inode>();
+ auto root_dentry = kstd::make_shared<kernel::filesystem::dentry>(nullptr, root_inode, "/");
+
+ WHEN("constructing a mount with the filesystem and root dentry")
+ {
+ auto mount = kernel::filesystem::mount{root_dentry, root_dentry, fs, nullptr, nullptr};
+
+ THEN("the mount has the correct filesystem, root dentry, mount dentry, and mount path")
+ {
+ REQUIRE(mount.get_filesystem() == fs);
+ REQUIRE(mount.root_dentry() == root_dentry);
+ REQUIRE(mount.mount_dentry() == root_dentry);
+ REQUIRE(mount.mount_path() == "/");
+ REQUIRE(mount.is_ready_to_unmount());
+ }
+
+ THEN("the mount has no parent mount and no source mount")
+ {
+ REQUIRE(mount.parent_mount() == nullptr);
+ REQUIRE(mount.source_mount() == nullptr);
+ }
+ }
+
+ WHEN("constructing a mount with a null filesystem")
+ {
+ THEN("the constructor panics")
+ {
+ REQUIRE_THROWS_AS((kernel::filesystem::mount{root_dentry, root_dentry, nullptr, nullptr, nullptr}),
+ kernel::tests::cpu::halt);
+ }
+ }
+ }
+}
+
+SCENARIO("Mount reference counting", "[filesystem][mount]")
+{
+ GIVEN("a filesystem and a root dentry")
+ {
+ auto fs = kstd::make_shared<kernel::tests::filesystem::filesystem>();
+ auto root_inode = kstd::make_shared<kernel::tests::filesystem::inode>();
+ auto root_dentry = kstd::make_shared<kernel::filesystem::dentry>(nullptr, root_inode, "/");
+
+ THEN("reference count can be incremented and decremented, the mount is ready to unmount when the reference "
+ "count == 0")
+ {
+ auto mount = kernel::filesystem::mount{root_dentry, root_dentry, fs, nullptr, nullptr};
+
+ mount.increment_ref_count();
+ REQUIRE(mount.ref_count() == 1);
+ REQUIRE_FALSE(mount.is_ready_to_unmount());
+
+ mount.increment_ref_count();
+ REQUIRE(mount.ref_count() == 2);
+ REQUIRE_FALSE(mount.is_ready_to_unmount());
+
+ mount.decrement_ref_count();
+ REQUIRE(mount.ref_count() == 1);
+ REQUIRE_FALSE(mount.is_ready_to_unmount());
+
+ mount.decrement_ref_count();
+ REQUIRE(mount.ref_count() == 0);
+ REQUIRE(mount.is_ready_to_unmount());
+ }
+
+ THEN("decrementing reference count when it is already zero does not decrement it below zero")
+ {
+ auto mount = kernel::filesystem::mount{root_dentry, root_dentry, fs, nullptr, nullptr};
+
+ REQUIRE_THROWS_AS(mount.decrement_ref_count(), std::runtime_error);
+ REQUIRE(mount.ref_count() == 0);
+ REQUIRE(mount.is_ready_to_unmount());
+ }
+ }
+} \ No newline at end of file
diff --git a/kernel/src/filesystem/mount_table.cpp b/kernel/src/filesystem/mount_table.cpp
new file mode 100644
index 0000000..e4baac7
--- /dev/null
+++ b/kernel/src/filesystem/mount_table.cpp
@@ -0,0 +1,79 @@
+#include <kernel/filesystem/mount_table.hpp>
+
+#include <kernel/filesystem/dentry.hpp>
+#include <kernel/filesystem/mount.hpp>
+
+#include <kstd/memory>
+#include <kstd/vector>
+
+#include <algorithm>
+#include <ranges>
+#include <string_view>
+
+namespace kernel::filesystem
+{
+ auto mount_table::has_child_mounts(kstd::shared_ptr<mount> const & parent_mount) const -> bool
+ {
+ return std::ranges::any_of(m_mounts,
+ [&parent_mount](auto const & mount) { return mount->parent_mount() == parent_mount; });
+ }
+
+ auto mount_table::add_mount(kstd::shared_ptr<mount> const & mount) -> void
+ {
+ m_mounts.push_back(mount);
+
+ if (auto source_mount = mount->source_mount())
+ {
+ source_mount->increment_ref_count();
+ }
+
+ if (auto mount_dentry = mount->mount_dentry())
+ {
+ mount_dentry->set_flag(dentry::dentry_flags::is_mount_point);
+ }
+ }
+
+ auto mount_table::remove_mount(std::string_view path) -> operation_result
+ {
+ auto mount_it = find_mount_iterator(path);
+ if (mount_it == m_mounts.end())
+ {
+ return operation_result::mount_not_found;
+ }
+
+ auto const & mount = *mount_it;
+ if (!mount->is_ready_to_unmount())
+ {
+ return operation_result::cannot_be_unmounted;
+ }
+ if (has_child_mounts(mount))
+ {
+ return operation_result::has_child_mounts;
+ }
+
+ if (auto source_mount = mount->source_mount())
+ {
+ source_mount->decrement_ref_count();
+ }
+
+ if (auto mount_dentry = mount->mount_dentry())
+ {
+ mount_dentry->unset_flag(dentry::dentry_flags::is_mount_point);
+ }
+
+ m_mounts.erase(mount_it);
+ return operation_result::removed;
+ }
+
+ auto mount_table::find_mount(std::string_view path) const -> kstd::shared_ptr<mount>
+ {
+ auto mount_it = find_mount_iterator(path);
+ return (mount_it != m_mounts.end()) ? *mount_it : nullptr;
+ }
+
+ auto mount_table::find_mount_iterator(std::string_view path) const
+ -> kstd::vector<kstd::shared_ptr<mount>>::const_iterator
+ {
+ return std::ranges::find_last_if(m_mounts, [&](auto const & mount) { return mount->mount_path() == path; }).begin();
+ }
+} // namespace kernel::filesystem \ No newline at end of file
diff --git a/kernel/src/filesystem/mount_table.tests.cpp b/kernel/src/filesystem/mount_table.tests.cpp
new file mode 100644
index 0000000..19b47b2
--- /dev/null
+++ b/kernel/src/filesystem/mount_table.tests.cpp
@@ -0,0 +1,184 @@
+#include <kernel/filesystem/mount_table.hpp>
+
+#include <kernel/filesystem/dentry.hpp>
+#include <kernel/filesystem/mount.hpp>
+#include <kernel/test_support/filesystem/filesystem.hpp>
+#include <kernel/test_support/filesystem/inode.hpp>
+
+#include <kstd/memory>
+#include <kstd/print>
+#include <kstd/vector>
+
+#include <catch2/catch_test_macros.hpp>
+
+#include <string_view>
+
+SCENARIO("Mount table construction", "[filesystem][mount_table]")
+{
+ GIVEN("an empty mount table")
+ {
+ kernel::filesystem::mount_table table;
+
+ THEN("removing any mount returns mount_not_found")
+ {
+ REQUIRE(table.remove_mount("/") == kernel::filesystem::mount_table::operation_result::mount_not_found);
+ REQUIRE(table.remove_mount("/any/path") == kernel::filesystem::mount_table::operation_result::mount_not_found);
+ }
+ }
+}
+
+SCENARIO("Adding, finding and removing mounts in the mount table", "[filesystem][mount_table]")
+{
+ GIVEN("a mount table and some mounts")
+ {
+ kernel::filesystem::mount_table table;
+
+ auto fs1 = kstd::make_shared<kernel::tests::filesystem::filesystem>();
+ auto root_dentry1 = kstd::make_shared<kernel::filesystem::dentry>(
+ nullptr, kstd::make_shared<kernel::tests::filesystem::inode>(), "/");
+ auto mount_dentry1 = kstd::make_shared<kernel::filesystem::dentry>(
+ nullptr, kstd::make_shared<kernel::tests::filesystem::inode>(), "/");
+ auto mount1 = kstd::make_shared<kernel::filesystem::mount>(mount_dentry1, root_dentry1, fs1, nullptr, nullptr);
+
+ auto fs2 = kstd::make_shared<kernel::tests::filesystem::filesystem>();
+ auto root_dentry2 = kstd::make_shared<kernel::filesystem::dentry>(
+ nullptr, kstd::make_shared<kernel::tests::filesystem::inode>(), "/");
+ auto mount_dentry2 = kstd::make_shared<kernel::filesystem::dentry>(
+ nullptr, kstd::make_shared<kernel::tests::filesystem::inode>(), "/mnt");
+ auto mount2 = kstd::make_shared<kernel::filesystem::mount>(mount_dentry2, root_dentry2, fs2, nullptr, nullptr);
+
+ table.add_mount(mount1);
+ table.add_mount(mount2);
+
+ THEN("dentry flags are set correctly for mounted dentries")
+ {
+ REQUIRE(mount_dentry1->has_flag(kernel::filesystem::dentry::dentry_flags::is_mount_point));
+ REQUIRE(mount_dentry2->has_flag(kernel::filesystem::dentry::dentry_flags::is_mount_point));
+ }
+
+ THEN("finding mounts by exact valid path returns the correct mount")
+ {
+ REQUIRE(table.find_mount("/") == mount1);
+ REQUIRE(table.find_mount("/mnt") == mount2);
+ }
+
+ THEN("finding mounts by exact invalid path returns null")
+ {
+ REQUIRE(table.find_mount("/nonexistent") == nullptr);
+ REQUIRE(table.find_mount("/mnt/file") == nullptr);
+ }
+
+ THEN("removing a mount that has no child mounts succeeds")
+ {
+ REQUIRE(table.remove_mount("/mnt") == kernel::filesystem::mount_table::operation_result::removed);
+ REQUIRE_FALSE(root_dentry2->has_flag(kernel::filesystem::dentry::dentry_flags::is_mount_point));
+ }
+
+ THEN("removing a mount that does not exist returns mount_not_found")
+ {
+ REQUIRE(table.remove_mount("/nonexistent") == kernel::filesystem::mount_table::operation_result::mount_not_found);
+ }
+ }
+
+ GIVEN("multiple mounts with the same path")
+ {
+ kernel::filesystem::mount_table table;
+
+ auto fs1 = kstd::make_shared<kernel::tests::filesystem::filesystem>();
+ auto root_dentry1 = kstd::make_shared<kernel::filesystem::dentry>(
+ nullptr, kstd::make_shared<kernel::tests::filesystem::inode>(), "/");
+ auto mount_dentry1 = kstd::make_shared<kernel::filesystem::dentry>(
+ nullptr, kstd::make_shared<kernel::tests::filesystem::inode>(), "/");
+ auto mount1 = kstd::make_shared<kernel::filesystem::mount>(mount_dentry1, root_dentry1, fs1, nullptr, nullptr);
+
+ auto fs2 = kstd::make_shared<kernel::tests::filesystem::filesystem>();
+ auto root_dentry2 = kstd::make_shared<kernel::filesystem::dentry>(
+ nullptr, kstd::make_shared<kernel::tests::filesystem::inode>(), "/");
+ auto mount_dentry2 = kstd::make_shared<kernel::filesystem::dentry>(
+ nullptr, kstd::make_shared<kernel::tests::filesystem::inode>(), "/");
+ auto mount2 = kstd::make_shared<kernel::filesystem::mount>(mount_dentry2, root_dentry2, fs2, nullptr, nullptr);
+
+ table.add_mount(mount1);
+ table.add_mount(mount2);
+
+ THEN("finding mounts by exact valid path returns the correct mount")
+ {
+ REQUIRE(table.find_mount("/") == mount2);
+ }
+
+ THEN("removing the topmost mount with the same path succeeds")
+ {
+ REQUIRE(table.remove_mount("/") == kernel::filesystem::mount_table::operation_result::removed);
+ REQUIRE_FALSE(root_dentry2->has_flag(kernel::filesystem::dentry::dentry_flags::is_mount_point));
+ }
+ }
+
+ GIVEN("a mount with child mounts")
+ {
+ kernel::filesystem::mount_table table;
+
+ auto fs1 = kstd::make_shared<kernel::tests::filesystem::filesystem>();
+ auto root_dentry1 = kstd::make_shared<kernel::filesystem::dentry>(
+ nullptr, kstd::make_shared<kernel::tests::filesystem::inode>(), "/");
+ auto mount_dentry1 = kstd::make_shared<kernel::filesystem::dentry>(
+ nullptr, kstd::make_shared<kernel::tests::filesystem::inode>(), "/");
+ auto mount1 = kstd::make_shared<kernel::filesystem::mount>(mount_dentry1, root_dentry1, fs1, nullptr, nullptr);
+
+ auto fs2 = kstd::make_shared<kernel::tests::filesystem::filesystem>();
+ auto root_dentry2 = kstd::make_shared<kernel::filesystem::dentry>(
+ nullptr, kstd::make_shared<kernel::tests::filesystem::inode>(), "/");
+ auto mount_dentry2 = kstd::make_shared<kernel::filesystem::dentry>(
+ mount_dentry1, kstd::make_shared<kernel::tests::filesystem::inode>(), "mnt");
+ auto mount2 = kstd::make_shared<kernel::filesystem::mount>(mount_dentry2, root_dentry2, fs2, mount1, nullptr);
+
+ auto fs3 = kstd::make_shared<kernel::tests::filesystem::filesystem>();
+ auto root_dentry3 = kstd::make_shared<kernel::filesystem::dentry>(
+ nullptr, kstd::make_shared<kernel::tests::filesystem::inode>(), "/");
+ auto mount_dentry3 = kstd::make_shared<kernel::filesystem::dentry>(
+ mount_dentry2, kstd::make_shared<kernel::tests::filesystem::inode>(), "submnt");
+ auto mount3 = kstd::make_shared<kernel::filesystem::mount>(mount_dentry3, root_dentry3, fs3, mount2, nullptr);
+
+ table.add_mount(mount1);
+ table.add_mount(mount2);
+ table.add_mount(mount3);
+
+ THEN("removing a mount with child mounts returns has_child_mounts")
+ {
+ REQUIRE(table.remove_mount("/") == kernel::filesystem::mount_table::operation_result::has_child_mounts);
+ REQUIRE(table.remove_mount("/mnt") == kernel::filesystem::mount_table::operation_result::has_child_mounts);
+ }
+
+ THEN("removing a leaf mount succeeds")
+ {
+ REQUIRE(table.remove_mount("/mnt/submnt") == kernel::filesystem::mount_table::operation_result::removed);
+ REQUIRE_FALSE(root_dentry3->has_flag(kernel::filesystem::dentry::dentry_flags::is_mount_point));
+ }
+ }
+}
+
+SCENARIO("Mount reference counting", "[filesystem][mount_table]")
+{
+ kernel::filesystem::mount_table table;
+
+ GIVEN("a filesystem and a root dentry")
+ {
+ auto fs = kstd::make_shared<kernel::tests::filesystem::filesystem>();
+ auto root_inode = kstd::make_shared<kernel::tests::filesystem::inode>();
+ auto root_dentry = kstd::make_shared<kernel::filesystem::dentry>(nullptr, root_inode, "/");
+
+ auto source_mount = kstd::make_shared<kernel::filesystem::mount>(root_dentry, root_dentry, fs, nullptr, nullptr);
+ auto mount = kstd::make_shared<kernel::filesystem::mount>(root_dentry, root_dentry, fs, nullptr, source_mount);
+
+ THEN("reference count of source mount is incremented when a mount is added to the mount table and decremented when "
+ "the mount is removed")
+ {
+ REQUIRE(source_mount->ref_count() == 0);
+
+ table.add_mount(mount);
+ REQUIRE(source_mount->ref_count() == 1);
+
+ REQUIRE(table.remove_mount("/") == kernel::filesystem::mount_table::operation_result::removed);
+ REQUIRE(source_mount->ref_count() == 0);
+ }
+ }
+}
diff --git a/kernel/src/filesystem/open_file_descriptor.cpp b/kernel/src/filesystem/open_file_descriptor.cpp
new file mode 100644
index 0000000..a5567bf
--- /dev/null
+++ b/kernel/src/filesystem/open_file_descriptor.cpp
@@ -0,0 +1,46 @@
+#include <kernel/filesystem/open_file_descriptor.hpp>
+
+#include <kernel/filesystem/dentry.hpp>
+
+#include <kstd/memory>
+#include <kstd/os/error.hpp>
+
+#include <cstddef>
+
+namespace kernel::filesystem
+{
+ open_file_descriptor::open_file_descriptor(kstd::shared_ptr<dentry> const & dentry)
+ : m_dentry(dentry)
+ , m_offset(0)
+ {
+ if (!dentry)
+ {
+ kstd::os::panic("[FILESYSTEM] open_file_descriptor constructed with null dentry.");
+ }
+ }
+
+ auto open_file_descriptor::read(void * buffer, size_t size) -> size_t
+ {
+ auto read_bytes = m_dentry->get_inode()->read(buffer, m_offset, size);
+ m_offset += read_bytes;
+ return read_bytes;
+ }
+
+ auto open_file_descriptor::write(void const * buffer, size_t size) -> size_t
+ {
+ auto written_bytes = m_dentry->get_inode()->write(buffer, m_offset, size);
+ m_offset += written_bytes;
+ return written_bytes;
+ }
+
+ auto open_file_descriptor::offset() const -> size_t
+ {
+ return m_offset;
+ }
+
+ auto open_file_descriptor::get_dentry() const -> kstd::shared_ptr<dentry> const &
+ {
+ return m_dentry;
+ }
+
+} // namespace kernel::filesystem \ No newline at end of file
diff --git a/kernel/src/filesystem/open_file_descriptor.tests.cpp b/kernel/src/filesystem/open_file_descriptor.tests.cpp
new file mode 100644
index 0000000..8c24cf0
--- /dev/null
+++ b/kernel/src/filesystem/open_file_descriptor.tests.cpp
@@ -0,0 +1,113 @@
+#include <kernel/filesystem/open_file_descriptor.hpp>
+
+#include <kernel/filesystem/dentry.hpp>
+#include <kernel/filesystem/inode.hpp>
+#include <kernel/filesystem/vfs.hpp>
+#include <kernel/test_support/filesystem/inode.hpp>
+#include <kernel/test_support/filesystem/storage_boot_module_vfs_fixture.hpp>
+
+#include <kstd/memory>
+#include <kstd/print>
+#include <kstd/vector>
+
+#include <catch2/catch_test_macros.hpp>
+
+#include <cstddef>
+#include <filesystem>
+#include <string_view>
+
+SCENARIO("Open file descriptor construction", "[filesystem][open_file_descriptor]")
+{
+ GIVEN("a dentry and an open file descriptor for that dentry")
+ {
+ auto inode = kstd::make_shared<kernel::tests::filesystem::inode>();
+ auto dentry = kstd::make_shared<kernel::filesystem::dentry>(nullptr, inode, "test_dentry");
+ auto file_descriptor = kernel::filesystem::open_file_descriptor{dentry};
+
+ THEN("the initial offset is zero")
+ {
+ REQUIRE(file_descriptor.offset() == 0);
+ }
+ }
+}
+
+SCENARIO("Open file descriptor read/write offset management", "[filesystem][open_file_descriptor]")
+{
+ GIVEN("a dentry that tracks read/write calls and an open file descriptor for that dentry")
+ {
+ auto inode = kstd::make_shared<kernel::tests::filesystem::inode>();
+ auto dentry = kstd::make_shared<kernel::filesystem::dentry>(nullptr, inode, "test_dentry");
+ auto file_descriptor = kernel::filesystem::open_file_descriptor{dentry};
+
+ THEN("the offset is updated correctly after reads")
+ {
+ REQUIRE(file_descriptor.read(nullptr, 100) == 100);
+ REQUIRE(file_descriptor.offset() == 100);
+ REQUIRE(file_descriptor.read(nullptr, 50) == 50);
+ REQUIRE(file_descriptor.offset() == 150);
+ }
+
+ THEN("the offset is updated correctly after writes")
+ {
+ REQUIRE(file_descriptor.write(nullptr, 200) == 200);
+ REQUIRE(file_descriptor.offset() == 200);
+ REQUIRE(file_descriptor.write(nullptr, 25) == 25);
+ REQUIRE(file_descriptor.offset() == 225);
+ }
+
+ THEN("reads and writes both update the same offset")
+ {
+ REQUIRE(file_descriptor.read(nullptr, 10) == 10);
+ REQUIRE(file_descriptor.offset() == 10);
+ REQUIRE(file_descriptor.write(nullptr, 20) == 20);
+ REQUIRE(file_descriptor.offset() == 30);
+ REQUIRE(file_descriptor.read(nullptr, 5) == 5);
+ REQUIRE(file_descriptor.offset() == 35);
+ REQUIRE(file_descriptor.write(nullptr, 15) == 15);
+ REQUIRE(file_descriptor.offset() == 50);
+ }
+ }
+}
+
+SCENARIO_METHOD(kernel::tests::filesystem::storage_boot_module_vfs_fixture, "Open file descriptor read with real image",
+ "[filesystem][open_file_descriptor][img]")
+{
+ auto const image_path = std::filesystem::path{KERNEL_TEST_ASSETS_DIR} / "ext2_1KB_fs.img";
+
+ GIVEN("an open file descriptor for a file in a real image")
+ {
+ REQUIRE(std::filesystem::exists(image_path));
+ REQUIRE_NOTHROW(setup_modules_from_img_and_init_vfs({"test_img_module"}, {image_path}));
+
+ auto & vfs = kernel::filesystem::vfs::get();
+ auto dentry = vfs.open("/information/info_1.txt");
+ REQUIRE(dentry != nullptr);
+ auto ofd = kstd::make_shared<kernel::filesystem::open_file_descriptor>(dentry);
+
+ THEN("the file can be read and the offset is updated")
+ {
+ kstd::vector<std::byte> buffer(32);
+ auto bytes_read = ofd->read(buffer.data(), buffer.size());
+ REQUIRE(bytes_read == 7);
+ REQUIRE(ofd->offset() == 7);
+
+ std::string_view buffer_as_str{reinterpret_cast<char *>(buffer.data()), static_cast<size_t>(bytes_read)};
+ REQUIRE(buffer_as_str == "info_1\n");
+ }
+
+ THEN("the file can be read multiple times")
+ {
+ kstd::vector<std::byte> buffer(4);
+ auto bytes_read_1 = ofd->read(buffer.data(), buffer.size() / 2);
+ REQUIRE(bytes_read_1 == buffer.size() / 2);
+ REQUIRE(ofd->offset() == buffer.size() / 2);
+
+ auto bytes_read_2 = ofd->read(buffer.data() + buffer.size() / 2, buffer.size() / 2);
+ REQUIRE(bytes_read_2 == buffer.size() / 2);
+ REQUIRE(ofd->offset() == buffer.size());
+
+ std::string_view buffer_as_str{reinterpret_cast<char *>(buffer.data()), bytes_read_1 + bytes_read_2};
+ REQUIRE(buffer_as_str == "info");
+ }
+ }
+}
diff --git a/kernel/src/filesystem/open_file_table.cpp b/kernel/src/filesystem/open_file_table.cpp
new file mode 100644
index 0000000..2afe3aa
--- /dev/null
+++ b/kernel/src/filesystem/open_file_table.cpp
@@ -0,0 +1,87 @@
+#include <kernel/filesystem/open_file_table.hpp>
+
+#include <kernel/filesystem/open_file_descriptor.hpp>
+
+#include <kapi/system.hpp>
+
+#include <kstd/memory>
+#include <kstd/unikstd.h>
+
+#include <algorithm>
+#include <cstddef>
+#include <optional>
+
+namespace
+{
+ constinit auto static global_open_file_table = std::optional<kernel::filesystem::open_file_table>{};
+} // namespace
+
+namespace kernel::filesystem
+{
+ auto open_file_table::init() -> void
+ {
+ if (global_open_file_table)
+ {
+ kapi::system::panic("[FILESYSTEM] Open file table has already been initialized.");
+ }
+
+ global_open_file_table.emplace(open_file_table{});
+ }
+
+ auto open_file_table::get() -> open_file_table &
+ {
+ if (!global_open_file_table)
+ {
+ kapi::system::panic("[FILESYSTEM] Open file table has not been initialized.");
+ }
+
+ return *global_open_file_table;
+ }
+
+ auto open_file_table::add_file(kstd::shared_ptr<open_file_descriptor> const & file_descriptor) -> kstd::ssize_t
+ {
+ if (!file_descriptor)
+ {
+ return -1;
+ }
+
+ auto it = std::ranges::find_if(m_open_files, [](auto const & open_file) { return open_file == nullptr; });
+ if (it != m_open_files.end())
+ {
+ *it = file_descriptor;
+ return it - m_open_files.begin();
+ }
+
+ m_open_files.push_back(file_descriptor);
+ return m_open_files.size() - 1;
+ }
+
+ auto open_file_table::file(size_t fd) const -> kstd::shared_ptr<open_file_descriptor>
+ {
+ if (fd >= m_open_files.size())
+ {
+ return nullptr;
+ }
+
+ return m_open_files.at(fd);
+ }
+
+ auto open_file_table::remove_file(size_t fd) -> kstd::ssize_t
+ {
+ if (fd >= m_open_files.size())
+ {
+ return -1;
+ }
+
+ m_open_files.at(fd) = nullptr;
+ return 0;
+ }
+} // namespace kernel::filesystem
+
+namespace kernel::tests::filesystem::open_file_table
+{
+ auto deinit() -> void
+ {
+ global_open_file_table.reset();
+ }
+} // namespace kernel::tests::filesystem::open_file_table
diff --git a/kernel/src/filesystem/open_file_table.tests.cpp b/kernel/src/filesystem/open_file_table.tests.cpp
new file mode 100644
index 0000000..3e91111
--- /dev/null
+++ b/kernel/src/filesystem/open_file_table.tests.cpp
@@ -0,0 +1,106 @@
+#include <kernel/filesystem/open_file_table.hpp>
+
+#include <kernel/filesystem/dentry.hpp>
+#include <kernel/filesystem/open_file_descriptor.hpp>
+#include <kernel/test_support/filesystem/inode.hpp>
+
+#include <kstd/memory>
+#include <kstd/print>
+#include <kstd/vector>
+
+#include <catch2/catch_test_macros.hpp>
+
+SCENARIO("Open file table add/get file", "[filesystem][open_file_table]")
+{
+ GIVEN("a open file table and an open file descriptor")
+ {
+ auto & table = kernel::filesystem::open_file_table::get();
+ auto inode = kstd::make_shared<kernel::tests::filesystem::inode>();
+ auto dentry = kstd::make_shared<kernel::filesystem::dentry>(nullptr, inode, "test_dentry");
+
+ auto file_descriptor_1 = kstd::make_shared<kernel::filesystem::open_file_descriptor>(dentry);
+ auto file_descriptor_2 = kstd::make_shared<kernel::filesystem::open_file_descriptor>(dentry);
+
+ WHEN("adding the open file descriptor to the open file table")
+ {
+ auto fd_1 = table.add_file(file_descriptor_1);
+ auto fd_2 = table.add_file(file_descriptor_2);
+ auto fd_3 = table.add_file(file_descriptor_2);
+
+ THEN("a valid file descriptor is returned")
+ {
+ REQUIRE(fd_1 == 0);
+ REQUIRE(fd_2 == 1);
+ REQUIRE(fd_3 == 2);
+ }
+
+ THEN("the file descriptor can be retrieved using the returned file descriptor")
+ {
+ auto retrieved_descriptor = table.file(fd_1);
+ REQUIRE(retrieved_descriptor == file_descriptor_1);
+ }
+ }
+ }
+
+ GIVEN("a invalid open file descriptor")
+ {
+ auto & table = kernel::filesystem::open_file_table::get();
+
+ THEN("adding a null file descriptor returns an error code")
+ {
+ auto fd = table.add_file(nullptr);
+ REQUIRE(fd == -1);
+ }
+
+ THEN("retrieving a file descriptor with an out-of-bounds file descriptor returns a null pointer")
+ {
+ auto retrieved_descriptor = table.file(1000);
+ REQUIRE(retrieved_descriptor == nullptr);
+ }
+ }
+}
+
+SCENARIO("Open file table remove file", "[filesystem][open_file_table]")
+{
+ GIVEN("a open file table with an open file descriptor")
+ {
+ auto & table = kernel::filesystem::open_file_table::get();
+ auto inode = kstd::make_shared<kernel::tests::filesystem::inode>();
+ auto dentry = kstd::make_shared<kernel::filesystem::dentry>(nullptr, inode, "test_dentry");
+ auto file_descriptor = kstd::make_shared<kernel::filesystem::open_file_descriptor>(dentry);
+ auto fd = table.add_file(file_descriptor);
+
+ WHEN("removing the file descriptor using the file descriptor")
+ {
+ table.remove_file(fd);
+
+ THEN("the file descriptor can no longer be retrieved using the file descriptor")
+ {
+ auto retrieved_descriptor = table.file(fd);
+ REQUIRE(retrieved_descriptor == nullptr);
+ }
+ }
+
+ WHEN("removing a file descriptor the other file descriptor keep the same index")
+ {
+ auto fd2 = table.add_file(file_descriptor);
+ table.remove_file(fd);
+
+ THEN("the second file descriptor can still be retrieved using its file descriptor")
+ {
+ auto retrieved_descriptor = table.file(fd2);
+ REQUIRE(retrieved_descriptor == file_descriptor);
+ }
+ }
+ }
+
+ GIVEN("an invalid file descriptor")
+ {
+ auto & table = kernel::filesystem::open_file_table::get();
+
+ THEN("removing a file with an out-of-bounds file descriptor does nothing")
+ {
+ REQUIRE_NOTHROW(table.remove_file(1000));
+ }
+ }
+} \ No newline at end of file
diff --git a/kernel/src/filesystem/path.tests.cpp b/kernel/src/filesystem/path.tests.cpp
new file mode 100644
index 0000000..3c18b5c
--- /dev/null
+++ b/kernel/src/filesystem/path.tests.cpp
@@ -0,0 +1,69 @@
+#include <kernel/filesystem/path.hpp>
+
+#include <catch2/catch_test_macros.hpp>
+
+#include <algorithm>
+#include <string>
+#include <string_view>
+#include <vector>
+
+SCENARIO("path utilities", "[filesystem][path]")
+{
+ GIVEN("valid and invalid paths")
+ {
+ THEN("valid absolute paths are recognized as valid")
+ {
+ REQUIRE(kernel::filesystem::path::is_valid_path("/valid/absolute/path"));
+ REQUIRE(kernel::filesystem::path::is_valid_path("/"));
+ }
+
+ THEN("valid relative paths are recognized as valid")
+ {
+ REQUIRE(kernel::filesystem::path::is_valid_path("valid/../relative/.././path"));
+ REQUIRE(kernel::filesystem::path::is_valid_path("valid/relative/path"));
+ REQUIRE(kernel::filesystem::path::is_valid_path("file.txt"));
+ }
+
+ THEN("invalid paths are recognized as invalid")
+ {
+ REQUIRE_FALSE(kernel::filesystem::path::is_valid_path(""));
+ REQUIRE_FALSE(kernel::filesystem::path::is_valid_path(std::string(4096, 'a')));
+ }
+
+ THEN("valid absolute paths are recognized as absolute")
+ {
+ REQUIRE(kernel::filesystem::path::is_valid_absolute_path("/valid/absolute/path"));
+ REQUIRE_FALSE(kernel::filesystem::path::is_valid_absolute_path("valid/relative/path"));
+ }
+
+ THEN("invalid paths are not recognized as absolute")
+ {
+ REQUIRE_FALSE(kernel::filesystem::path::is_valid_absolute_path(""));
+ REQUIRE_FALSE(kernel::filesystem::path::is_valid_absolute_path(std::string(4096, 'a')));
+ REQUIRE_FALSE(kernel::filesystem::path::is_valid_absolute_path("invalid/absolute/path"));
+ }
+
+ THEN("valid relative paths are recognized as relative")
+ {
+ REQUIRE(kernel::filesystem::path::is_valid_relative_path("valid/relative/path"));
+ REQUIRE_FALSE(kernel::filesystem::path::is_valid_relative_path("/valid/absolute/path"));
+ }
+
+ THEN("invalid paths are not recognized as relative")
+ {
+ REQUIRE_FALSE(kernel::filesystem::path::is_valid_relative_path(""));
+ REQUIRE_FALSE(kernel::filesystem::path::is_valid_relative_path(std::string(4096, 'a')));
+ REQUIRE_FALSE(kernel::filesystem::path::is_valid_relative_path("/invalid/absolute/path"));
+ }
+ }
+
+ GIVEN("a valid path")
+ {
+ THEN("it can be split into components")
+ {
+ auto components = kernel::filesystem::path::split("/a/b///c/d.txt");
+ std::vector<std::string_view> expected = {"a", "b", "c", "d.txt"};
+ REQUIRE(std::ranges::equal(components, expected));
+ }
+ }
+} \ No newline at end of file
diff --git a/kernel/src/filesystem/rootfs/filesystem.cpp b/kernel/src/filesystem/rootfs/filesystem.cpp
new file mode 100644
index 0000000..7fe5c1e
--- /dev/null
+++ b/kernel/src/filesystem/rootfs/filesystem.cpp
@@ -0,0 +1,47 @@
+#include <kernel/filesystem/rootfs/filesystem.hpp>
+
+#include <kernel/filesystem/filesystem.hpp>
+#include <kernel/filesystem/inode.hpp>
+#include <kernel/filesystem/rootfs/inode.hpp>
+#include <kernel/filesystem/type.hpp>
+
+#include <kstd/memory>
+
+#include <string_view>
+
+namespace kernel::filesystem::rootfs
+{
+
+ struct type final : kernel::filesystem::type
+ {
+ [[nodiscard]] auto name() const noexcept -> std::string_view override
+ {
+ return "rootfs";
+ }
+
+ [[nodiscard]] auto requires_device() const noexcept -> bool override
+ {
+ return true;
+ }
+
+ [[nodiscard]] auto make_instance() const -> kstd::shared_ptr<kernel::filesystem::filesystem> override
+ {
+ return kstd::make_shared<filesystem>();
+ }
+ };
+
+ [[gnu::used]]
+ constexpr auto registration = type_registration<type>{};
+
+ auto filesystem::mount(kstd::shared_ptr<kernel::filesystem::inode> const &) -> operation_result
+ {
+ m_root_inode = kstd::make_shared<inode>();
+ return operation_result::success;
+ }
+
+ auto filesystem::lookup(kstd::shared_ptr<kernel::filesystem::inode> const &, std::string_view) const
+ -> kstd::shared_ptr<kernel::filesystem::inode>
+ {
+ return nullptr;
+ }
+} // namespace kernel::filesystem::rootfs
diff --git a/kernel/src/filesystem/rootfs/filesystem.tests.cpp b/kernel/src/filesystem/rootfs/filesystem.tests.cpp
new file mode 100644
index 0000000..ae320e9
--- /dev/null
+++ b/kernel/src/filesystem/rootfs/filesystem.tests.cpp
@@ -0,0 +1,38 @@
+#include <kernel/filesystem/rootfs/filesystem.hpp>
+
+#include <kernel/filesystem/filesystem.hpp>
+
+#include <kstd/memory>
+#include <kstd/print>
+#include <kstd/vector>
+
+#include <catch2/catch_test_macros.hpp>
+
+SCENARIO("Rootfs filesystem mount and lookup", "[filesystem][rootfs][filesystem]")
+{
+ GIVEN("a mounted rootfs filesystem")
+ {
+ auto fs = kernel::filesystem::rootfs::filesystem{};
+ auto result = fs.mount(nullptr);
+
+ THEN("the filesystem can be mounted successfully")
+ {
+ REQUIRE(result == kernel::filesystem::filesystem::operation_result::success);
+ REQUIRE(fs.root_inode() != nullptr);
+ }
+
+ THEN("looking up a non-existent directory returns null")
+ {
+ auto non_existent_inode_1 = fs.lookup(fs.root_inode(), "");
+ REQUIRE(non_existent_inode_1 == nullptr);
+ auto non_existent_inode_2 = fs.lookup(fs.root_inode(), "nonexistent");
+ REQUIRE(non_existent_inode_2 == nullptr);
+ }
+
+ THEN("looking up with a null parent inode returns null")
+ {
+ auto result = fs.lookup(nullptr, "dev");
+ REQUIRE(result == nullptr);
+ }
+ }
+}
diff --git a/kernel/src/filesystem/rootfs/inode.cpp b/kernel/src/filesystem/rootfs/inode.cpp
new file mode 100644
index 0000000..f64fb87
--- /dev/null
+++ b/kernel/src/filesystem/rootfs/inode.cpp
@@ -0,0 +1,23 @@
+#include <kernel/filesystem/inode.hpp>
+
+#include <kernel/filesystem/rootfs/inode.hpp>
+
+#include <cstddef>
+
+namespace kernel::filesystem::rootfs
+{
+ auto inode::read(void *, size_t, size_t) const -> size_t
+ {
+ return 0;
+ }
+
+ auto inode::write(void const *, size_t, size_t) -> size_t
+ {
+ return 0;
+ }
+
+ auto inode::is_directory() const -> bool
+ {
+ return true;
+ }
+} // namespace kernel::filesystem::rootfs
diff --git a/kernel/src/filesystem/rootfs/inode.tests.cpp b/kernel/src/filesystem/rootfs/inode.tests.cpp
new file mode 100644
index 0000000..f4b634f
--- /dev/null
+++ b/kernel/src/filesystem/rootfs/inode.tests.cpp
@@ -0,0 +1,37 @@
+#include <kernel/filesystem/rootfs/inode.hpp>
+
+#include <kstd/memory>
+#include <kstd/print>
+#include <kstd/vector>
+
+#include <catch2/catch_test_macros.hpp>
+
+SCENARIO("Rootfs inode read/write", "[filesystem][rootfs][inode]")
+{
+ GIVEN("a rootfs inode")
+ {
+ auto inode = kernel::filesystem::rootfs::inode{};
+
+ WHEN("reading from the inode")
+ {
+ kstd::vector<char> buffer(10);
+ auto bytes_read = inode.read(buffer.data(), 0, buffer.size());
+
+ THEN("no bytes are read")
+ {
+ REQUIRE(bytes_read == 0);
+ }
+ }
+
+ WHEN("writing to the inode")
+ {
+ kstd::vector<char> buffer(10, 'x');
+ auto bytes_written = inode.write(buffer.data(), 0, buffer.size());
+
+ THEN("no bytes are written")
+ {
+ REQUIRE(bytes_written == 0);
+ }
+ }
+ }
+}
diff --git a/kernel/src/filesystem/type_registry.cpp b/kernel/src/filesystem/type_registry.cpp
new file mode 100644
index 0000000..d917c81
--- /dev/null
+++ b/kernel/src/filesystem/type_registry.cpp
@@ -0,0 +1,72 @@
+#include <kernel/filesystem/type_registry.hpp>
+
+#include <kapi/system.hpp>
+
+#include <kstd/memory>
+#include <kstd/print>
+
+#include <algorithm>
+#include <cstddef>
+#include <optional>
+#include <ranges>
+#include <span>
+
+namespace kernel::filesystem
+{
+
+ extern "C"
+ {
+ extern type_registry::pointer const __start_fs_types;
+ extern type_registry::pointer const __stop_fs_types;
+ }
+
+ namespace
+ {
+ auto constinit instance = std::optional<type_registry>{};
+ }
+
+ auto type_registry::init() -> void
+ {
+ if (instance)
+ {
+ kapi::system::panic("[FILESYSTEM] tried to initialize type registry more than once!");
+ }
+
+ instance.emplace();
+
+ auto type_descriptors = std::span{&__start_fs_types, &__stop_fs_types} | //
+ std::views::filter([](auto p) { return p != nullptr; });
+
+ std::ranges::for_each(type_descriptors, [](auto descriptor) {
+ kstd::println("[FILESYSTEM] registering '{}'", descriptor->name());
+ instance->add(descriptor);
+ });
+ }
+
+ auto type_registry::get() -> type_registry &
+ {
+ if (!instance)
+ {
+ kapi::system::panic("[FILESYSTEM] type registry has not been initialized!");
+ }
+
+ return *instance;
+ }
+
+ auto type_registry::add(pointer descriptor) -> bool
+ {
+ auto result = m_descriptors.emplace(descriptor->name(), descriptor);
+ return result.second;
+ }
+
+ auto type_registry::all() const noexcept -> std::span<pointer const>
+ {
+ return {m_descriptors.values().begin(), m_descriptors.values().end()};
+ }
+
+ auto type_registry::size() const noexcept -> std::size_t
+ {
+ return m_descriptors.size();
+ }
+
+} // namespace kernel::filesystem
diff --git a/kernel/src/filesystem/type_registry.tests.cpp b/kernel/src/filesystem/type_registry.tests.cpp
new file mode 100644
index 0000000..8382579
--- /dev/null
+++ b/kernel/src/filesystem/type_registry.tests.cpp
@@ -0,0 +1,77 @@
+#include <kernel/filesystem/type_registry.hpp>
+
+#include <kernel/filesystem/filesystem.hpp>
+#include <kernel/filesystem/type.hpp>
+
+#include <kstd/memory>
+
+#include <catch2/catch_test_macros.hpp>
+
+#include <iterator>
+#include <string_view>
+
+struct test_type final : kernel::filesystem::type
+{
+ [[nodiscard]] auto name() const noexcept -> std::string_view override
+ {
+ return "bht_testfs";
+ }
+
+ [[nodiscard]] auto requires_device() const noexcept -> bool override
+ {
+ return false;
+ }
+
+ [[nodiscard]] auto make_instance() const -> kstd::shared_ptr<kernel::filesystem::filesystem> override
+ {
+ return nullptr;
+ }
+};
+
+SCENARIO("Filesystem type registry initialization and construction", "[filesystem]")
+{
+ GIVEN("A default constructed type_registry")
+ {
+ auto instance = kernel::filesystem::type_registry{};
+
+ WHEN("getting the span of filesystem descriptors")
+ {
+ auto descriptors = instance.all();
+
+ THEN("the span is empty")
+ {
+ REQUIRE(descriptors.empty());
+ }
+ }
+ }
+}
+
+SCENARIO("Filesystem type registry modifiers", "[filesystem]")
+{
+ GIVEN("A default constructed type_registry")
+ {
+ auto instance = kernel::filesystem::type_registry{};
+
+ WHEN("adding a type descriptor")
+ {
+ auto descriptor = test_type{};
+
+ instance.add(kstd::make_observer(&descriptor));
+
+ THEN("the size of the registry is one")
+ {
+ REQUIRE(instance.size() == 1);
+ }
+
+ THEN("the span is not empty")
+ {
+ REQUIRE_FALSE(instance.all().empty());
+ }
+
+ THEN("the span's size is equal to the registry size")
+ {
+ REQUIRE(std::size(instance.all()) == std::size(instance));
+ }
+ }
+ }
+}
diff --git a/kernel/src/filesystem/vfs.cpp b/kernel/src/filesystem/vfs.cpp
new file mode 100644
index 0000000..e5dff8c
--- /dev/null
+++ b/kernel/src/filesystem/vfs.cpp
@@ -0,0 +1,299 @@
+#include <kernel/filesystem/vfs.hpp>
+
+#include <kernel/filesystem/constants.hpp>
+#include <kernel/filesystem/dentry.hpp>
+#include <kernel/filesystem/devfs/filesystem.hpp>
+#include <kernel/filesystem/filesystem.hpp>
+#include <kernel/filesystem/mount.hpp>
+#include <kernel/filesystem/mount_table.hpp>
+#include <kernel/filesystem/path.hpp>
+#include <kernel/filesystem/rootfs/filesystem.hpp>
+
+#include <kapi/system.hpp>
+
+#include <kstd/memory>
+#include <kstd/vector>
+
+#include <algorithm>
+#include <cstdint>
+#include <optional>
+#include <ranges>
+#include <string_view>
+#include <utility>
+
+namespace
+{
+ constinit auto static active_vfs = std::optional<kernel::filesystem::vfs>{};
+} // namespace
+
+namespace kernel::filesystem
+{
+ auto vfs::init() -> void
+ {
+ if (active_vfs)
+ {
+ kapi::system::panic("[FILESYSTEM] vfs has already been initialized.");
+ }
+
+ active_vfs.emplace();
+ }
+
+ vfs::vfs()
+ {
+ // mount rootfs at /
+ auto root_fs = kstd::make_shared<rootfs::filesystem>();
+ root_fs->mount(nullptr);
+
+ auto root_fs_root_dentry = kstd::make_shared<dentry>(nullptr, root_fs->root_inode(), "/");
+ auto root_mount = kstd::make_shared<mount>(nullptr, root_fs_root_dentry, root_fs, nullptr, nullptr);
+ m_mount_table.add_mount(root_mount);
+
+ // mount devfs at /dev (inside rootfs, temporary, will be shadowed)
+ auto device_fs = kstd::make_shared<devfs::filesystem>();
+ device_fs->mount(nullptr);
+ graft_persistent_device_fs(device_fs);
+
+ // mount boot fs at / (shadows rootfs), re-graft devfs
+ auto [boot_device_dentry, boot_device_mount_context] = resolve_path_internal("/dev/ram0");
+ if (boot_device_dentry && boot_device_mount_context)
+ {
+ if (auto boot_root_fs = kernel::filesystem::filesystem::probe_and_mount(boot_device_dentry->get_inode()))
+ {
+ if (auto root_dentry = resolve_path("/"))
+ {
+ do_mount_internal(root_dentry, root_mount, boot_root_fs, boot_device_mount_context);
+ graft_persistent_device_fs(device_fs);
+ }
+ }
+ }
+ }
+
+ auto vfs::get() -> vfs &
+ {
+ if (!active_vfs)
+ {
+ kapi::system::panic("[FILESYSTEM] vfs has not been initialized.");
+ }
+
+ return *active_vfs;
+ }
+
+ auto vfs::open(std::string_view path) -> kstd::shared_ptr<dentry>
+ {
+ auto [dentry, mount] = resolve_path_internal(path);
+ if (!dentry || !mount)
+ {
+ return nullptr;
+ }
+ mount->increment_ref_count();
+ return dentry;
+ }
+
+ auto vfs::close(std::string_view path) -> operation_result
+ {
+ if (auto mount = find_mount(path))
+ {
+ mount->decrement_ref_count();
+ return operation_result::success;
+ }
+ return operation_result::invalid_path;
+ }
+
+ auto vfs::do_mount(std::string_view source, std::string_view target) -> operation_result
+ {
+ if (!path::is_valid_path(source) || !path::is_valid_path(target))
+ {
+ return operation_result::invalid_path;
+ }
+
+ auto [mount_point_dentry, mount_context] = resolve_path_internal(target);
+ if (mount_point_dentry && mount_context)
+ {
+ auto [source_dentry, source_mount_context] = resolve_path_internal(source);
+ if (source_dentry && source_mount_context)
+ {
+ if (auto fs = kernel::filesystem::filesystem::probe_and_mount(source_dentry->get_inode()))
+ {
+ do_mount_internal(mount_point_dentry, mount_context, fs, source_mount_context);
+ return operation_result::success;
+ }
+ return operation_result::invalid_filesystem;
+ }
+ return operation_result::non_existent_path;
+ }
+ return operation_result::mount_point_not_found;
+ }
+
+ auto vfs::unmount(std::string_view path) -> operation_result
+ {
+ if (!path::is_valid_path(path))
+ {
+ return operation_result::invalid_path;
+ }
+
+ auto remove_result = m_mount_table.remove_mount(path);
+ if (remove_result == mount_table::operation_result::removed)
+ {
+ return operation_result::success;
+ }
+ else if (remove_result == mount_table::operation_result::mount_not_found)
+ {
+ return operation_result::mount_point_not_found;
+ }
+
+ return operation_result::unmount_failed;
+ }
+
+ auto vfs::do_mount_internal(kstd::shared_ptr<dentry> const & mount_point_dentry,
+ kstd::shared_ptr<mount> const & parent_mount, kstd::shared_ptr<filesystem> const & fs,
+ kstd::shared_ptr<mount> const & source_mount) -> void
+ {
+ auto new_fs_root =
+ kstd::make_shared<dentry>(mount_point_dentry->parent(), fs->root_inode(), mount_point_dentry->name());
+ auto new_mount = kstd::make_shared<mount>(mount_point_dentry, new_fs_root, fs, parent_mount, source_mount);
+ m_mount_table.add_mount(new_mount);
+ }
+
+ auto vfs::graft_persistent_device_fs(kstd::shared_ptr<devfs::filesystem> const & device_fs) -> void
+ {
+ auto [root_mount_point_dentry, root_mount] = resolve_path_internal("/");
+ if (root_mount_point_dentry && root_mount)
+ {
+ auto dev_dentry = root_mount_point_dentry->find_child("dev");
+ if (!dev_dentry)
+ {
+ dev_dentry = kstd::make_shared<dentry>(root_mount_point_dentry, device_fs->root_inode(), "dev");
+ root_mount_point_dentry->add_child(dev_dentry);
+ }
+
+ do_mount_internal(dev_dentry, root_mount, device_fs);
+ }
+ }
+
+ auto vfs::resolve_path_internal(std::string_view path) const
+ -> std::pair<kstd::shared_ptr<dentry>, kstd::shared_ptr<mount>>
+ {
+ if (!path::is_valid_absolute_path(path))
+ {
+ return {nullptr, nullptr};
+ }
+
+ auto current_mount = m_mount_table.find_mount("/");
+ if (!current_mount)
+ {
+ kapi::system::panic("[FILESYSTEM] no root mount found.");
+ }
+
+ auto current_dentry = current_mount->root_dentry();
+
+ auto path_parts = path::split(path);
+ kstd::vector path_parts_vector(path_parts.begin(), path_parts.end());
+ std::ranges::reverse(path_parts_vector);
+
+ auto symlink_counter = 0uz;
+
+ while (!path_parts_vector.empty())
+ {
+ auto part = path_parts_vector.back();
+ path_parts_vector.pop_back();
+
+ if (part == ".")
+ {
+ continue;
+ }
+
+ if (part == "..")
+ {
+ auto parent_dentry = current_dentry->parent();
+
+ if (current_dentry == current_mount->root_dentry())
+ {
+ if (current_mount->mount_path() == "/")
+ {
+ continue;
+ }
+
+ if (auto parent_mount = current_mount->parent_mount())
+ {
+ current_mount = parent_mount;
+ current_dentry = parent_dentry;
+ }
+ }
+
+ current_dentry = parent_dentry;
+ continue;
+ }
+
+ auto next_dentry = current_dentry->find_child(part);
+ if (!next_dentry)
+ {
+ auto current_fs = current_mount->get_filesystem();
+ auto found_inode = current_fs->lookup(current_dentry->get_inode(), part);
+ if (!found_inode)
+ {
+ return {nullptr, nullptr};
+ }
+
+ next_dentry = kstd::make_shared<dentry>(current_dentry, found_inode, part);
+ current_dentry->add_child(next_dentry);
+ }
+ else if (next_dentry->has_flag(dentry::dentry_flags::is_mount_point))
+ {
+ current_mount = m_mount_table.find_mount(next_dentry->absolute_path());
+ if (!current_mount)
+ {
+ kapi::system::panic("[FILESYSTEM] mount for dentry with mounted flag not found.");
+ }
+
+ next_dentry = current_mount->root_dentry();
+ }
+
+ if (next_dentry->get_inode()->is_symbolic_link())
+ {
+ if (symlink_counter++ > constants::symloop_max)
+ {
+ return {nullptr, nullptr};
+ }
+
+ kstd::vector<uint8_t> buffer(constants::symlink_max_path_length);
+ auto const bytes_read = next_dentry->get_inode()->read(buffer.data(), 0, buffer.size());
+ auto const symbolic_link_path = std::string_view{reinterpret_cast<char const *>(buffer.data()), bytes_read};
+
+ auto symbolic_link_parts = path::split(symbolic_link_path);
+ kstd::vector symbolic_link_parts_vector(symbolic_link_parts.begin(), symbolic_link_parts.end());
+ std::ranges::reverse(symbolic_link_parts_vector);
+
+ path_parts_vector.insert_range(path_parts_vector.end(), symbolic_link_parts_vector);
+
+ if (path::is_valid_absolute_path(symbolic_link_path))
+ {
+ current_mount = m_mount_table.find_mount("/");
+ current_dentry = current_mount->root_dentry();
+ }
+ continue;
+ }
+
+ current_dentry = next_dentry;
+ }
+ return {current_dentry, current_mount};
+ }
+
+ auto vfs::resolve_path(std::string_view path) const -> kstd::shared_ptr<dentry>
+ {
+ return resolve_path_internal(path).first;
+ }
+
+ auto vfs::find_mount(std::string_view path) const -> kstd::shared_ptr<mount>
+ {
+ return resolve_path_internal(path).second;
+ }
+
+} // namespace kernel::filesystem
+
+namespace kernel::tests::filesystem::vfs
+{
+ auto deinit() -> void
+ {
+ active_vfs.reset();
+ }
+} // namespace kernel::tests::filesystem::vfs
diff --git a/kernel/src/filesystem/vfs.tests.cpp b/kernel/src/filesystem/vfs.tests.cpp
new file mode 100644
index 0000000..f1d0df0
--- /dev/null
+++ b/kernel/src/filesystem/vfs.tests.cpp
@@ -0,0 +1,568 @@
+#include <kernel/filesystem/vfs.hpp>
+
+#include <kernel/filesystem/open_file_descriptor.hpp>
+#include <kernel/test_support/filesystem/storage_boot_module_vfs_fixture.hpp>
+
+#include <kstd/memory>
+#include <kstd/vector>
+
+#include <catch2/catch_test_macros.hpp>
+
+#include <cstddef>
+#include <filesystem>
+#include <stdexcept>
+#include <string_view>
+
+SCENARIO_METHOD(kernel::tests::filesystem::storage_boot_module_vfs_fixture, "VFS with dummy modules",
+ "[filesystem][vfs]")
+{
+ GIVEN("an initialized boot module registry with multiple modules")
+ {
+ REQUIRE_NOTHROW(setup_modules_and_init_vfs(5));
+
+ THEN("vfs initializes and provides /dev mount")
+ {
+ auto & vfs = kernel::filesystem::vfs::get();
+ auto dev = vfs.open("/dev");
+
+ REQUIRE(dev != nullptr);
+ }
+
+ THEN("vfs initializes root filesystem with boot device if boot module is present")
+ {
+ auto & vfs = kernel::filesystem::vfs::get();
+ auto root_file = vfs.open("/");
+
+ REQUIRE(root_file != nullptr);
+ }
+ }
+}
+
+SCENARIO_METHOD(kernel::tests::filesystem::storage_boot_module_vfs_fixture, "VFS with file backed image",
+ "[filesystem][vfs][img]")
+{
+ auto const image_path_1 = std::filesystem::path{KERNEL_TEST_ASSETS_DIR} / "ext2_1KB_fs.img";
+ auto const image_path_2 = std::filesystem::path{KERNEL_TEST_ASSETS_DIR} / "ext2_2KB_fs.img";
+ auto const image_path_3 = std::filesystem::path{KERNEL_TEST_ASSETS_DIR} / "ext2_4KB_fs.img";
+
+ GIVEN("a real image file")
+ {
+ REQUIRE(std::filesystem::exists(image_path_1));
+ REQUIRE_NOTHROW(setup_modules_from_img_and_init_vfs({"test_img_module"}, {image_path_1}));
+
+ THEN("vfs initializes and provides expected mount points")
+ {
+ auto & vfs = kernel::filesystem::vfs::get();
+ auto root = vfs.open("/");
+ auto dev = vfs.open("/dev");
+ auto information = vfs.open("/information/info_1.txt");
+
+ REQUIRE(root != nullptr);
+ REQUIRE(dev != nullptr);
+ REQUIRE(information != nullptr);
+ }
+ }
+
+ GIVEN("a real image file containing a /dev directory")
+ {
+ REQUIRE(std::filesystem::exists(image_path_2));
+ REQUIRE_NOTHROW(setup_modules_from_img_and_init_vfs({"test_img_module_2"}, {image_path_2}));
+
+ THEN("vfs hides the image's /dev behind the devfs mount")
+ {
+ auto & vfs = kernel::filesystem::vfs::get();
+
+ auto image_1 = vfs.open("/dev/image_1.txt");
+ REQUIRE(image_1 == nullptr);
+
+ auto dev = vfs.open("/dev/ram0");
+ REQUIRE(dev != nullptr);
+ }
+ }
+
+ GIVEN("three real image files")
+ {
+ REQUIRE(std::filesystem::exists(image_path_1));
+ REQUIRE(std::filesystem::exists(image_path_2));
+ REQUIRE(std::filesystem::exists(image_path_3));
+ REQUIRE_NOTHROW(setup_modules_from_img_and_init_vfs({"test_img_module_1", "test_img_module_2", "test_img_module_3"},
+ {image_path_1, image_path_2, image_path_3}));
+
+ auto & vfs = kernel::filesystem::vfs::get();
+
+ THEN("vfs initializes first module as root")
+ {
+ auto & vfs = kernel::filesystem::vfs::get();
+ auto info1 = vfs.open("/information/info_1.txt");
+ auto info2 = vfs.open("/information/info_2.txt");
+
+ REQUIRE(info1 != nullptr);
+ REQUIRE(info2 != nullptr);
+ }
+
+ THEN("second image can be mounted, data retrieved and unmounted again")
+ {
+ REQUIRE(vfs.do_mount("/dev/ram16", "/information") == kernel::filesystem::vfs::operation_result::success);
+
+ auto mounted_monkey_1 = vfs.open("/information/monkey_house/monkey_1.txt");
+ REQUIRE(mounted_monkey_1 != nullptr);
+ REQUIRE(vfs.close(mounted_monkey_1->absolute_path()) == kernel::filesystem::vfs::operation_result::success);
+
+ REQUIRE(vfs.unmount("/information") == kernel::filesystem::vfs::operation_result::success);
+ auto unmounted_monkey_1 = vfs.open("/information/monkey_house/monkey_1.txt");
+ REQUIRE(unmounted_monkey_1 == nullptr);
+
+ auto info_1 = vfs.open("/information/info_1.txt");
+ REQUIRE(info_1 != nullptr);
+ }
+
+ THEN("third image can be mounted in a mounted file system, unmount only if no child mount exists")
+ {
+ REQUIRE(vfs.do_mount("/dev/ram16", "/information") == kernel::filesystem::vfs::operation_result::success);
+ REQUIRE(vfs.do_mount("/dev/ram32", "/information/monkey_house/infrastructure") ==
+ kernel::filesystem::vfs::operation_result::success);
+
+ auto mounted_monkey_1 = vfs.open("/information/monkey_house/monkey_1.txt");
+ auto mounted_fish1 = vfs.open("/information/monkey_house/infrastructure/enclosures/aquarium/tank_1/fish_1.txt");
+
+ REQUIRE(mounted_monkey_1 != nullptr);
+ REQUIRE(mounted_fish1 != nullptr);
+
+ REQUIRE(vfs.close(mounted_monkey_1->absolute_path()) == kernel::filesystem::vfs::operation_result::success);
+ REQUIRE(vfs.close(mounted_fish1->absolute_path()) == kernel::filesystem::vfs::operation_result::success);
+
+ REQUIRE(vfs.unmount("/information") == kernel::filesystem::vfs::operation_result::unmount_failed);
+ REQUIRE(vfs.unmount("/information/monkey_house/infrastructure") ==
+ kernel::filesystem::vfs::operation_result::success);
+ REQUIRE(vfs.unmount("/information") == kernel::filesystem::vfs::operation_result::success);
+ }
+
+ THEN("image can be mounted, unmount only if no files are open")
+ {
+ REQUIRE(vfs.do_mount("/dev/ram16", "/information") == kernel::filesystem::vfs::operation_result::success);
+
+ auto mounted_monkey_1 = vfs.open("/information/monkey_house/monkey_1.txt");
+ REQUIRE(mounted_monkey_1 != nullptr);
+
+ REQUIRE(vfs.unmount("/information") == kernel::filesystem::vfs::operation_result::unmount_failed);
+
+ REQUIRE(vfs.close(mounted_monkey_1->absolute_path()) == kernel::filesystem::vfs::operation_result::success);
+
+ REQUIRE(vfs.unmount("/information") == kernel::filesystem::vfs::operation_result::success);
+ }
+
+ THEN("file with invalid path or not opened file cannot be closed")
+ {
+ REQUIRE(vfs.close("invalid_path") == kernel::filesystem::vfs::operation_result::invalid_path);
+ REQUIRE_THROWS_AS(vfs.close("/information/info_1.txt"), std::runtime_error);
+ }
+
+ THEN("file cannot be closed twice")
+ {
+ auto info_1 = vfs.open("/information/info_1.txt");
+ REQUIRE(info_1 != nullptr);
+
+ REQUIRE(vfs.close(info_1->absolute_path()) == kernel::filesystem::vfs::operation_result::success);
+ REQUIRE_THROWS_AS(vfs.close(info_1->absolute_path()), std::runtime_error);
+ }
+
+ THEN("images can be stacked mounted and correct file system is unmounted again")
+ {
+ REQUIRE(vfs.do_mount("/dev/ram16", "/information") == kernel::filesystem::vfs::operation_result::success);
+ REQUIRE(vfs.do_mount("/dev/ram32", "/information") == kernel::filesystem::vfs::operation_result::success);
+
+ auto mounted_tickets = vfs.open("/information/entrance/tickets.txt");
+ REQUIRE(mounted_tickets != nullptr);
+
+ REQUIRE(vfs.close(mounted_tickets->absolute_path()) == kernel::filesystem::vfs::operation_result::success);
+
+ REQUIRE(vfs.unmount("/information") == kernel::filesystem::vfs::operation_result::success);
+ mounted_tickets = vfs.open("/information/entrance/tickets.txt");
+ REQUIRE(mounted_tickets == nullptr);
+
+ auto mounted_monkey = vfs.open("/information/monkey_house/monkey_1.txt");
+ REQUIRE(mounted_monkey != nullptr);
+ }
+
+ THEN("image can be mounted on / file opened and unmounted again")
+ {
+ auto info_1 = vfs.open("/information/info_1.txt");
+ REQUIRE(info_1 != nullptr);
+
+ REQUIRE(vfs.do_mount("/dev/ram16", "/") == kernel::filesystem::vfs::operation_result::success);
+
+ info_1 = vfs.open("/information/info_1.txt");
+ REQUIRE(info_1 == nullptr);
+
+ auto water = vfs.open("/monkey_house/infrastructure/water.txt");
+ REQUIRE(water != nullptr);
+
+ REQUIRE(vfs.close(water->absolute_path()) == kernel::filesystem::vfs::operation_result::success);
+
+ REQUIRE(vfs.unmount("/") == kernel::filesystem::vfs::operation_result::success);
+
+ info_1 = vfs.open("/information/info_1.txt");
+ REQUIRE(info_1 != nullptr);
+ }
+
+ THEN("image can be mounted on / just the boot root has /dev")
+ {
+ auto info_1 = vfs.open("/information/info_1.txt");
+ REQUIRE(info_1 != nullptr);
+
+ REQUIRE(vfs.do_mount("/dev/ram16", "/") == kernel::filesystem::vfs::operation_result::success);
+
+ info_1 = vfs.open("/information/info_1.txt");
+ REQUIRE(info_1 == nullptr);
+
+ auto water = vfs.open("/monkey_house/infrastructure/water.txt");
+ REQUIRE(water != nullptr);
+
+ REQUIRE(vfs.close(water->absolute_path()) == kernel::filesystem::vfs::operation_result::success);
+
+ auto dev_ram_16 = vfs.open("/dev/ram16");
+ REQUIRE(dev_ram_16 == nullptr);
+
+ REQUIRE(vfs.do_mount("/dev/ram32", "/") == kernel::filesystem::vfs::operation_result::non_existent_path);
+
+ REQUIRE(vfs.unmount("/") == kernel::filesystem::vfs::operation_result::success);
+
+ auto dev_ram_32 = vfs.open("/dev/ram32");
+ REQUIRE(dev_ram_32 != nullptr);
+ }
+
+ THEN("boot root can be unmounted and remounted again but /dev is not re-grafted")
+ {
+ auto info_1 = vfs.open("/information/info_1.txt");
+ REQUIRE(info_1 != nullptr);
+
+ REQUIRE(vfs.close(info_1->absolute_path()) == kernel::filesystem::vfs::operation_result::success);
+
+ REQUIRE(vfs.unmount("/dev") == kernel::filesystem::vfs::operation_result::success);
+ REQUIRE(vfs.unmount("/") == kernel::filesystem::vfs::operation_result::success);
+
+ info_1 = vfs.open("/information/info_1.txt");
+ REQUIRE(info_1 == nullptr);
+
+ REQUIRE(vfs.do_mount("/dev/ram0", "/") == kernel::filesystem::vfs::operation_result::success);
+
+ info_1 = vfs.open("/information/info_1.txt");
+ REQUIRE(info_1 != nullptr);
+
+ auto dev_ram_0 = vfs.open("/dev/ram0");
+ REQUIRE(dev_ram_0 == nullptr);
+ }
+
+ THEN("mount with null file system fails")
+ {
+ REQUIRE(vfs.do_mount("/closed.txt", "/information") ==
+ kernel::filesystem::vfs::operation_result::invalid_filesystem);
+ }
+
+ THEN("mount with invalid path fails")
+ {
+ REQUIRE(vfs.do_mount("/dev/ram16", "") == kernel::filesystem::vfs::operation_result::invalid_path);
+ REQUIRE(vfs.do_mount("/dev/ram16", "information") ==
+ kernel::filesystem::vfs::operation_result::mount_point_not_found);
+ }
+
+ THEN("mount with non-existent source path fails")
+ {
+ REQUIRE(vfs.do_mount("/dev/nonexistent", "/information") ==
+ kernel::filesystem::vfs::operation_result::non_existent_path);
+ }
+
+ THEN("mount with non-existent mount point fails")
+ {
+ REQUIRE(vfs.do_mount("/dev/ram16", "/information/nonexistent") ==
+ kernel::filesystem::vfs::operation_result::mount_point_not_found);
+ }
+
+ THEN("unmount with invalid path fails")
+ {
+ REQUIRE(vfs.unmount("") == kernel::filesystem::vfs::operation_result::invalid_path);
+ REQUIRE(vfs.unmount("information") == kernel::filesystem::vfs::operation_result::mount_point_not_found);
+ }
+
+ THEN("unmounting non-existent mount point returns expected error code")
+ {
+ REQUIRE(vfs.unmount("/information/nonexistent") ==
+ kernel::filesystem::vfs::operation_result::mount_point_not_found);
+ }
+
+ THEN("a file can be access if . in the path")
+ {
+ auto info_1 = vfs.open("/information/./info_1.txt");
+ REQUIRE(info_1 != nullptr);
+ }
+
+ THEN("a file can be accessed within the same mount if path contains .. ")
+ {
+ auto info_1 = vfs.open("/archiv/../information/info_1.txt");
+ REQUIRE(info_1 != nullptr);
+
+ auto img = vfs.open("/archiv/../information/../archiv/2024.img");
+ REQUIRE(img != nullptr);
+ }
+
+ THEN("a file can be accessed over multiple mounts if path contains .. or . ")
+ {
+ REQUIRE(vfs.do_mount("/dev/ram16", "/information") == kernel::filesystem::vfs::operation_result::success);
+
+ auto img = vfs.open("/information/monkey_house/caretaker/../../../../../../archiv/2024.img");
+ REQUIRE(img != nullptr);
+
+ auto dev_32 = vfs.open("/information/monkey_house/caretaker/../../../dev/ram32");
+ REQUIRE(dev_32 != nullptr);
+
+ auto water = vfs.open("/information/./monkey_house/infrastructure/water.txt");
+ REQUIRE(water != nullptr);
+ }
+
+ THEN("a file can be accessed over multiple mounts (device and file) if path contains .. ")
+ {
+ REQUIRE(vfs.do_mount("/dev/ram16", "/information") == kernel::filesystem::vfs::operation_result::success);
+ REQUIRE(vfs.do_mount("/archiv/2024.img", "/information/monkey_house/infrastructure") ==
+ kernel::filesystem::vfs::operation_result::success);
+
+ auto pig_1 = vfs.open("/information/monkey_house/infrastructure/stable/pig_1.txt");
+ REQUIRE(pig_1 != nullptr);
+
+ auto isabelle =
+ vfs.open("/information/monkey_house/infrastructure/stable/../../../monkey_house/caretaker/isabelle.txt");
+ REQUIRE(isabelle != nullptr);
+
+ auto closed = vfs.open("/information/monkey_house/infrastructure/stable/../../../../closed.txt");
+ REQUIRE(closed != nullptr);
+ }
+ }
+
+ GIVEN("A real image file containing as filesystem formatted files")
+ {
+ REQUIRE(std::filesystem::exists(image_path_1));
+ REQUIRE_NOTHROW(setup_modules_from_img_and_init_vfs({"test_img_module_1"}, {image_path_1}));
+
+ THEN("the file-filesystem in the image can be mounted, files can be read and unmounted again")
+ {
+ auto & vfs = kernel::filesystem::vfs::get();
+ REQUIRE(vfs.do_mount("/archiv/2024.img", "/information") == kernel::filesystem::vfs::operation_result::success);
+
+ auto info_1 = vfs.open("/information/info_1.txt");
+ REQUIRE(info_1 == nullptr);
+
+ auto dentry = vfs.open("/information/sheep_1.txt");
+ REQUIRE(dentry != nullptr);
+ auto sheep_1_ofd = kstd::make_shared<kernel::filesystem::open_file_descriptor>(dentry);
+
+ kstd::vector<std::byte> buffer(7);
+ auto bytes_read = sheep_1_ofd->read(buffer.data(), buffer.size());
+ std::string_view buffer_as_str{reinterpret_cast<char *>(buffer.data()), bytes_read};
+ REQUIRE(buffer_as_str == "sheep_1");
+
+ REQUIRE(vfs.close(dentry->absolute_path()) == kernel::filesystem::vfs::operation_result::success);
+
+ REQUIRE(vfs.unmount("/information") == kernel::filesystem::vfs::operation_result::success);
+ auto unmounted_sheep_1 = vfs.open("/information/sheep_1.txt");
+ REQUIRE(unmounted_sheep_1 == nullptr);
+ }
+
+ THEN("the file-filesystem in the image can be mounted and in this filesystem can another file-filesystem be "
+ "mounted, files can be read and unmounted again")
+ {
+ auto & vfs = kernel::filesystem::vfs::get();
+ REQUIRE(vfs.do_mount("/archiv/2024.img", "/information") == kernel::filesystem::vfs::operation_result::success);
+ REQUIRE(vfs.do_mount("/archiv/2025.img", "/information/stable") ==
+ kernel::filesystem::vfs::operation_result::success);
+
+ auto sheep_1 = vfs.open("/information/sheep_1.txt");
+ auto goat_1 = vfs.open("/information/stable/petting_zoo/goat_1.txt");
+ REQUIRE(sheep_1 != nullptr);
+ REQUIRE(goat_1 != nullptr);
+
+ auto sheep_1_ofd = kstd::make_shared<kernel::filesystem::open_file_descriptor>(sheep_1);
+ auto goat_1_ofd = kstd::make_shared<kernel::filesystem::open_file_descriptor>(goat_1);
+
+ kstd::vector<std::byte> sheep_buffer(7);
+ auto bytes_read = sheep_1_ofd->read(sheep_buffer.data(), sheep_buffer.size());
+ std::string_view buffer_as_str{reinterpret_cast<char *>(sheep_buffer.data()), bytes_read};
+ REQUIRE(buffer_as_str == "sheep_1");
+
+ kstd::vector<std::byte> goat_buffer(6);
+ bytes_read = goat_1_ofd->read(goat_buffer.data(), goat_buffer.size());
+ buffer_as_str = std::string_view{reinterpret_cast<char *>(goat_buffer.data()), bytes_read};
+ REQUIRE(buffer_as_str == "goat_1");
+
+ REQUIRE(vfs.close(sheep_1->absolute_path()) == kernel::filesystem::vfs::operation_result::success);
+ REQUIRE(vfs.close(goat_1->absolute_path()) == kernel::filesystem::vfs::operation_result::success);
+
+ REQUIRE(vfs.unmount("/information") == kernel::filesystem::vfs::operation_result::unmount_failed);
+
+ REQUIRE(vfs.unmount("/information/stable") == kernel::filesystem::vfs::operation_result::success);
+ auto unmounted_goat_1 = vfs.open("/information/stable/petting_zoo/goat_1.txt");
+ REQUIRE(unmounted_goat_1 == nullptr);
+
+ auto still_mounted_sheep_1 = vfs.open("/information/sheep_1.txt");
+ REQUIRE(still_mounted_sheep_1 != nullptr);
+
+ REQUIRE(vfs.close(still_mounted_sheep_1->absolute_path()) == kernel::filesystem::vfs::operation_result::success);
+
+ REQUIRE(vfs.unmount("/information") == kernel::filesystem::vfs::operation_result::success);
+ auto unmounted_sheep_1 = vfs.open("/information/sheep_1.txt");
+ REQUIRE(unmounted_sheep_1 == nullptr);
+ }
+ }
+
+ GIVEN("two real image files where the second contains as filesystem formatted files")
+ {
+ REQUIRE(std::filesystem::exists(image_path_1));
+ REQUIRE(std::filesystem::exists(image_path_3));
+ REQUIRE_NOTHROW(
+ setup_modules_from_img_and_init_vfs({"test_img_module_3", "test_img_module_1"}, {image_path_3, image_path_1}));
+
+ auto & vfs = kernel::filesystem::vfs::get();
+
+ THEN("cannot unmount a filesystem if files are mounted")
+ {
+ REQUIRE(vfs.do_mount("/dev/ram16", "/entrance") == kernel::filesystem::vfs::operation_result::success);
+ REQUIRE(vfs.do_mount("/entrance/archiv/2024.img", "/enclosures") ==
+ kernel::filesystem::vfs::operation_result::success);
+
+ REQUIRE(vfs.unmount("/entrance") == kernel::filesystem::vfs::operation_result::unmount_failed);
+ REQUIRE(vfs.unmount("/enclosures") == kernel::filesystem::vfs::operation_result::success);
+ REQUIRE(vfs.unmount("/entrance") == kernel::filesystem::vfs::operation_result::success);
+ }
+
+ THEN("can mount filesystem onto the directory that contains it")
+ {
+ REQUIRE(vfs.do_mount("/dev/ram16", "/entrance") == kernel::filesystem::vfs::operation_result::success);
+ REQUIRE(vfs.do_mount("/entrance/archiv/2024.img", "/entrance") ==
+ kernel::filesystem::vfs::operation_result::success);
+
+ REQUIRE(vfs.unmount("/entrance") == kernel::filesystem::vfs::operation_result::success);
+ REQUIRE(vfs.unmount("/entrance") == kernel::filesystem::vfs::operation_result::success);
+ }
+ }
+
+ GIVEN("A real image files, containing symbolic links")
+ {
+ REQUIRE(std::filesystem::exists(image_path_1));
+ REQUIRE_NOTHROW(setup_modules_from_img_and_init_vfs({"test_img_module_1"}, {image_path_1}));
+
+ THEN("file can be opened through absolute symbolic link")
+ {
+ auto & vfs = kernel::filesystem::vfs::get();
+ auto info_1 = vfs.open("/symlinks/info_1_absolute");
+ REQUIRE(info_1 != nullptr);
+ }
+
+ THEN("file can be opened through relative symbolic link")
+ {
+ auto & vfs = kernel::filesystem::vfs::get();
+ auto info_1 = vfs.open("/symlinks/info_1_relative");
+ REQUIRE(info_1 != nullptr);
+ }
+
+ THEN("file can be opened through symbolic link pointing absolute to the directory containing the file")
+ {
+ auto & vfs = kernel::filesystem::vfs::get();
+ auto info_1 = vfs.open("/symlinks/information_directory_absolute/info_1.txt");
+ REQUIRE(info_1 != nullptr);
+ }
+
+ THEN("file can be opened through symbolic link pointing relative to the directory containing the file")
+ {
+ auto & vfs = kernel::filesystem::vfs::get();
+ auto info_1 = vfs.open("/symlinks/information_directory_relative/info_1.txt");
+ REQUIRE(info_1 != nullptr);
+ }
+
+ THEN("symbolic link with path traversing back to the root")
+ {
+ auto & vfs = kernel::filesystem::vfs::get();
+ auto info_1 = vfs.open("/symlinks/traverse_back_5_times/information/info_1.txt");
+ REQUIRE(info_1 != nullptr);
+ }
+
+ THEN("symbolic link containing an invalid absolute path is handled correctly")
+ {
+ auto & vfs = kernel::filesystem::vfs::get();
+ auto invalid_symlink = vfs.open("/symlinks/invalid_absolute");
+ REQUIRE(invalid_symlink == nullptr);
+ }
+
+ THEN("symbolic link containing an invalid relative path is handled correctly")
+ {
+ auto & vfs = kernel::filesystem::vfs::get();
+ auto invalid_symlink = vfs.open("/symlinks/invalid_relative");
+ REQUIRE(invalid_symlink == nullptr);
+ }
+
+ THEN("circular symbolic links are detected and handled correctly")
+ {
+ auto & vfs = kernel::filesystem::vfs::get();
+ auto circular_symlink = vfs.open("/symlinks/symloop_a");
+ REQUIRE(circular_symlink == nullptr);
+ }
+ }
+
+ GIVEN("A real image file containing as filesystem formatted files and this filesystem contains a symbolic link")
+ {
+ REQUIRE(std::filesystem::exists(image_path_1));
+ REQUIRE_NOTHROW(setup_modules_from_img_and_init_vfs({"test_img_module_1"}, {image_path_1}));
+
+ auto & vfs = kernel::filesystem::vfs::get();
+ vfs.do_mount("/archiv/2024.img", "/information");
+
+ THEN("file can be opened through symbolic link pointing to the parent filesystem")
+ {
+ auto closed_file = vfs.open("/information/symlinks/traverse_back_twice/closed.txt");
+ REQUIRE(closed_file != nullptr);
+ }
+ }
+
+ GIVEN("Two real images, one containing a symbolic link leaving and reentering filesystem again")
+ {
+ REQUIRE(std::filesystem::exists(image_path_1));
+ REQUIRE(std::filesystem::exists(image_path_2));
+ REQUIRE_NOTHROW(
+ setup_modules_from_img_and_init_vfs({"test_img_module_1", "test_img_module_2"}, {image_path_1, image_path_2}));
+
+ auto & vfs = kernel::filesystem::vfs::get();
+ vfs.do_mount("/dev/ram16", "/information");
+
+ THEN("file can be opened through symbolic link pointing to the parent filesystem and back into the mounted "
+ "filesystem again")
+ {
+ auto monkey_1 = vfs.open("/information/symlinks/leave_and_reenter_mount/monkey_1.txt");
+ REQUIRE(monkey_1 != nullptr);
+ }
+ }
+
+ GIVEN("One real image containing a very long symbolic link")
+ {
+ REQUIRE(std::filesystem::exists(image_path_3));
+ REQUIRE_NOTHROW(setup_modules_from_img_and_init_vfs({"test_img_module_3"}, {image_path_3}));
+
+ auto & vfs = kernel::filesystem::vfs::get();
+
+ THEN("file can be opened through symbolic link with a long path")
+ {
+ auto fish_30 = vfs.open("/symlinks/very_long_symlink");
+ REQUIRE(fish_30 != nullptr);
+ }
+ }
+
+ GIVEN("One real image containing a valid symbolic link chain")
+ {
+ REQUIRE(std::filesystem::exists(image_path_3));
+ REQUIRE_NOTHROW(setup_modules_from_img_and_init_vfs({"test_img_module_3"}, {image_path_3}));
+
+ auto & vfs = kernel::filesystem::vfs::get();
+
+ THEN("file can be opened through symbolic link chain")
+ {
+ auto map = vfs.open("/symlinks/symlink_chain_1/map.txt");
+ REQUIRE(map != nullptr);
+ }
+ }
+}
diff --git a/kernel/src/main.cpp b/kernel/src/main.cpp
index 01bcbb0..8dc1349 100644
--- a/kernel/src/main.cpp
+++ b/kernel/src/main.cpp
@@ -1,20 +1,152 @@
-#include "kapi/cio.hpp"
-#include "kapi/memory.hpp"
-#include "kapi/system.hpp"
+#include "kernel/filesystem/type_registry.hpp"
+#include <kernel/devices/storage/management.hpp>
+#include <kernel/filesystem/open_file_table.hpp>
+#include <kernel/filesystem/vfs.hpp>
+#include <kernel/memory.hpp>
-#include "kernel/memory.hpp"
+#include <kapi/boot_modules.hpp>
+#include <kapi/cio.hpp>
+#include <kapi/cpu.hpp>
+#include <kapi/devices.hpp>
+#include <kapi/filesystem.hpp>
+#include <kapi/interrupts.hpp>
+#include <kapi/memory.hpp>
+#include <kapi/system.hpp>
+#include <kstd/format>
#include <kstd/print>
+#include <kstd/units>
+#include <kstd/vector>
+
+#include <cstddef>
+#include <string_view>
+
+using namespace kstd::units_literals;
+
+auto run_demo() -> void
+{
+ // 1) open a file
+ kstd::println("attempting to open /entrance/tickets.txt");
+ auto fd_1 = kapi::filesystem::open("/entrance/tickets.txt");
+ if (fd_1 == -1)
+ {
+ kapi::system::panic("demo failed");
+ }
+ else
+ {
+ kstd::println("--> successfully opened /entrance/tickets.txt with file descriptor {}", fd_1);
+ }
+
+ // 2) read from the file
+ kstd::vector<std::byte> buffer_1{10};
+ auto bytes_read = kapi::filesystem::read(fd_1, buffer_1.data(), buffer_1.size());
+ auto buffer_as_str = std::string_view{reinterpret_cast<char *>(buffer_1.data()), static_cast<size_t>(bytes_read)};
+ kstd::println("--> read {} bytes from /entrance/tickets.txt: {}", bytes_read, buffer_as_str);
+ kstd::println("");
+
+ // 3) show that /entrance/information/info_1.txt is not accessible before mounting
+ kstd::println("attempting to open /entrance/information/info_1.txt before mounting");
+ auto fd_before_mount = kapi::filesystem::open("/entrance/information/info_1.txt");
+ if (fd_before_mount == -1)
+ {
+ kstd::println("--> as expected the file could not be opened before mounting");
+ }
+
+ // 4) mount a new filesystem on top of /entrance
+ kstd::println("mount /dev/ram16 to /entrance");
+ if (kapi::filesystem::mount("/dev/ram16", "/entrance") == 0)
+ {
+ kstd::println("--> successfully mounted /dev/ram16 to /entrance");
+ }
+ else
+ {
+ kapi::system::panic("demo failed");
+ }
+ kstd::println("");
+
+ // 5) open a file from the new filesystem
+ kstd::println("attempting to open /entrance/information/info_1.txt");
+ auto fd_2 = kapi::filesystem::open("/entrance/information/info_1.txt");
+ if (fd_2 != -1)
+ {
+ kstd::println("--> successfully opened /entrance/information/info_1.txt with file descriptor {}", fd_2);
+ }
+ else
+ {
+ kapi::system::panic("demo failed");
+ }
+
+ // 6) read from the new file
+ kstd::vector<std::byte> buffer_2{10};
+ bytes_read = kapi::filesystem::read(fd_2, buffer_2.data(), buffer_2.size());
+ buffer_as_str = std::string_view{reinterpret_cast<char *>(buffer_2.data()), static_cast<size_t>(bytes_read)};
+ kstd::println("--> read {} bytes from /entrance/information/info_1.txt: {} ", bytes_read, buffer_as_str);
+
+ // 7) open device as file
+ kstd::println("attempting to open /dev/ram32 as a file");
+ auto fd_3 = kapi::filesystem::open("/dev/ram32");
+ if (fd_3 != -1)
+ {
+ kstd::println("--> successfully opened /dev/ram32 as a file with file descriptor {}", fd_3);
+ }
+ else
+ {
+ kapi::system::panic("demo failed");
+ }
+
+ // 8) read from the device file
+ kstd::vector<std::byte> buffer_3{2};
+ bytes_read = kapi::filesystem::read(fd_3, buffer_3.data(), buffer_3.size());
+ kstd::println("--> read {} bytes from /dev/ram32: {::#04x} ", bytes_read, buffer_3);
+
+ // 9) write to the device file
+ auto const default_buffer_value = std::byte{0xAA};
+ kstd::vector<std::byte> write_buffer{default_buffer_value, default_buffer_value};
+ auto bytes_written = kapi::filesystem::write(fd_3, write_buffer.data(), write_buffer.size());
+ kstd::println("--> written {} bytes to /dev/ram32: {::#04x}", bytes_written, write_buffer);
+
+ // 10) do memory dump to show that the write to the device file had an effect
+}
auto main() -> int
{
kapi::cio::init();
kstd::println("[OS] IO subsystem initialized.");
+ kapi::cpu::init();
+
kapi::memory::init();
kernel::memory::init_heap(kapi::memory::heap_base);
- kstd::println("[OS] Memory subsystem initialized.");
kapi::system::memory_initialized();
+ kapi::memory::init_mmio(kapi::memory::mmio_base, 1_GiB / kapi::memory::page::size);
+ kstd::println("[OS] Memory subsystem initialized.");
+
+ kapi::devices::init();
+ kstd::println("[OS] System root bus initialized.");
+
+ kapi::devices::init_platform_devices();
+ kstd::println("[OS] Platform devices initialized.");
+
+ kapi::interrupts::enable();
+ kstd::println("[OS] Interrupts enabled.");
+
+ kapi::boot_modules::init();
+ kstd::println("[OS] Boot module registry initialized.");
+
+ kernel::devices::storage::management::init();
+ kstd::println("[OS] Storage management initialized.");
+
+ kernel::filesystem::open_file_table::init();
+ kstd::println("[OS] Global open file table initialized.");
+
+ kernel::filesystem::type_registry::init();
+ kstd::println("[OS] Builtin filesystems registered.");
+
+ kernel::filesystem::vfs::init();
+ kstd::println("[OS] Virtual filesystem initialized.");
+
+ // TODO BA-FS26 remove demo code?
+ // run_demo();
kapi::system::panic("Returning from kernel main!");
}
diff --git a/kernel/src/memory.cpp b/kernel/src/memory.cpp
index 0f614f0..6a85c0e 100644
--- a/kernel/src/memory.cpp
+++ b/kernel/src/memory.cpp
@@ -1,16 +1,15 @@
-#include "kernel/memory.hpp"
+#include <kernel/memory.hpp>
-#include "kapi/memory.hpp"
-#include "kapi/system.hpp"
+#include <kernel/memory/block_list_allocator.hpp>
+#include <kernel/memory/heap_allocator.hpp>
-#include "kernel/memory/block_list_allocator.hpp"
-#include "kernel/memory/heap_allocator.hpp"
+#include <kapi/memory.hpp>
+#include <kapi/system.hpp>
#include <kstd/print>
+#include <kstd/units>
#include <atomic>
-#include <cstddef>
-#include <new>
#include <optional>
namespace kernel::memory
@@ -22,7 +21,7 @@ namespace kernel::memory
{
null_allocator static instance;
- [[nodiscard]] auto allocate(std::size_t, std::align_val_t) noexcept -> void * override
+ [[nodiscard]] auto allocate(kstd::units::bytes, kstd::units::bytes) noexcept -> void * override
{
kstd::print(kstd::print_sink::stderr, "Tried to allocate memory without an active heap!");
return nullptr;
diff --git a/kernel/src/memory/bitmap_allocator.cpp b/kernel/src/memory/bitmap_allocator.cpp
index c010f77..240e2af 100644
--- a/kernel/src/memory/bitmap_allocator.cpp
+++ b/kernel/src/memory/bitmap_allocator.cpp
@@ -1,11 +1,12 @@
-#include "kernel/memory/bitmap_allocator.hpp"
+#include <kernel/memory/bitmap_allocator.hpp>
-#include "kapi/memory.hpp"
+#include <kapi/memory.hpp>
#include <algorithm>
#include <cstddef>
#include <cstdint>
#include <optional>
+#include <ranges>
#include <span>
#include <utility>
@@ -17,7 +18,9 @@ namespace kernel::memory
, m_frame_count{frame_count}
, m_last_index{}
{
- std::ranges::fill(m_bitmap, ~0uz);
+ constexpr auto bits_per_word = 64uz;
+ auto to_fill = (frame_count + bits_per_word - 1) / bits_per_word;
+ std::ranges::fill(std::views::take(m_bitmap, to_fill), ~0uz);
}
auto bitmap_frame_allocator::allocate_many(std::size_t count) noexcept
@@ -78,22 +81,25 @@ namespace kernel::memory
auto bitmap_frame_allocator::test(std::size_t index) const noexcept -> bool
{
- auto entry_entry = index / 64;
- auto entry_offset = index % 64;
+ constexpr auto bits_per_word = 64uz;
+ auto entry_entry = index / bits_per_word;
+ auto entry_offset = index % bits_per_word;
return (m_bitmap[entry_entry] & (1uz << entry_offset));
}
auto bitmap_frame_allocator::set(std::size_t index) noexcept -> void
{
- auto entry_entry = index / 64;
- auto entry_offset = index % 64;
+ constexpr auto bits_per_word = 64uz;
+ auto entry_entry = index / bits_per_word;
+ auto entry_offset = index % bits_per_word;
m_bitmap[entry_entry] |= (1uz << entry_offset);
}
auto bitmap_frame_allocator::clear(std::size_t index) noexcept -> void
{
- auto entry_entry = index / 64;
- auto entry_offset = index % 64;
+ constexpr auto bits_per_word = 64uz;
+ auto entry_entry = index / bits_per_word;
+ auto entry_offset = index % bits_per_word;
m_bitmap[entry_entry] &= ~(1uz << entry_offset);
}
diff --git a/kernel/src/memory/bitmap_allocator.tests.cpp b/kernel/src/memory/bitmap_allocator.tests.cpp
new file mode 100644
index 0000000..05d11a3
--- /dev/null
+++ b/kernel/src/memory/bitmap_allocator.tests.cpp
@@ -0,0 +1,288 @@
+#include <kernel/memory/bitmap_allocator.hpp>
+
+#include <kapi/memory.hpp>
+
+#include <catch2/catch_test_macros.hpp>
+#include <catch2/matchers/catch_matchers.hpp>
+#include <catch2/matchers/catch_matchers_range_equals.hpp>
+
+#include <cstdint>
+#include <limits>
+#include <ranges>
+#include <span>
+#include <vector>
+
+constexpr auto all_bits_set = std::numeric_limits<std::uint64_t>::max();
+constexpr auto available_frames = 1024uz;
+
+SCENARIO("Bitmap allocator construction and initialization", "[memory][bitmap_allocator]")
+{
+ GIVEN("A storage region")
+ {
+ auto storage = std::vector(available_frames / 64, 0uz);
+
+ WHEN("constructing the allocator with 0 frames")
+ {
+ auto allocator = kernel::memory::bitmap_frame_allocator{std::span(storage), 0};
+
+ THEN("the storage region is not modified")
+ {
+ REQUIRE_THAT(storage, Catch::Matchers::RangeEquals(std::vector(16, 0uz)));
+ }
+ }
+
+ WHEN("constructing with 1 frame")
+ {
+ auto allocator = kernel::memory::bitmap_frame_allocator{std::span(storage), 1};
+
+ THEN("the first word of the storage region is set to all ones")
+ {
+ REQUIRE_THAT(std::views::take(storage, 1), Catch::Matchers::RangeEquals(std::vector(1, all_bits_set)));
+ }
+
+ THEN("the rest of the storage region is not modified")
+ {
+ REQUIRE_THAT(std::views::drop(storage, 1), Catch::Matchers::RangeEquals(std::vector(15, 0uz)));
+ }
+ }
+
+ WHEN("constructing with 64 frames")
+ {
+ auto allocator = kernel::memory::bitmap_frame_allocator{std::span(storage), 64};
+
+ THEN("the first word of the storage region is set to all ones")
+ {
+ REQUIRE_THAT(std::views::take(storage, 1), Catch::Matchers::RangeEquals(std::vector(1, all_bits_set)));
+ }
+
+ THEN("the rest of the storage region is not modified")
+ {
+ REQUIRE_THAT(std::views::drop(storage, 1), Catch::Matchers::RangeEquals(std::vector(15, 0uz)));
+ }
+ }
+
+ WHEN("constructing with all available frames")
+ {
+ auto allocator = kernel::memory::bitmap_frame_allocator{std::span(storage), available_frames};
+
+ THEN("the storage region is filled with all ones")
+ {
+ REQUIRE_THAT(storage, Catch::Matchers::RangeEquals(std::vector(16, all_bits_set)));
+ }
+ }
+
+ WHEN("constructing with half the available frames")
+ {
+ auto allocator = kernel::memory::bitmap_frame_allocator{std::span(storage), available_frames / 2};
+
+ THEN("the first half of the storage region is filled with all ones")
+ {
+ REQUIRE_THAT(std::views::take(storage, (available_frames / 2) / 64),
+ Catch::Matchers::RangeEquals(std::vector((available_frames / 2) / 64, all_bits_set)));
+ }
+
+ THEN("the second half of the storage region is filled with all zeros")
+ {
+ REQUIRE_THAT(std::views::drop(storage, (available_frames / 2) / 64),
+ Catch::Matchers::RangeEquals(std::vector((available_frames / 2) / 64, 0uz)));
+ }
+ }
+ }
+}
+
+SCENARIO("Bitmap allocator frame allocation", "[memory][bitmap_allocator]")
+{
+ GIVEN("A storage region")
+ {
+ auto storage = std::vector(available_frames / 64, 0uz);
+
+ AND_GIVEN("an allocator constructed with all available frames but no free ones")
+ {
+ auto allocator = kernel::memory::bitmap_frame_allocator{std::span(storage), available_frames};
+
+ WHEN("allocating 1 frame")
+ {
+ auto result = allocator.allocate_many(1);
+
+ THEN("the result is empty")
+ {
+ REQUIRE_FALSE(result.has_value());
+ }
+ }
+ }
+
+ AND_GIVEN("an allocator constructed with all available frames but only one free one")
+ {
+ auto allocator = kernel::memory::bitmap_frame_allocator{std::span(storage), available_frames};
+ allocator.release_many({kapi::memory::frame{0}, 1});
+
+ WHEN("allocating 1 frame")
+ {
+ auto result = allocator.allocate_many(1);
+
+ THEN("the result is not empty")
+ {
+ REQUIRE(result.has_value());
+ }
+
+ THEN("the result contains 1 frame")
+ {
+ REQUIRE(result->second == 1);
+ }
+ }
+
+ WHEN("allocating more frames than are free")
+ {
+ auto result = allocator.allocate_many(2);
+
+ THEN("the result is empty")
+ {
+ REQUIRE_FALSE(result.has_value());
+ }
+
+ AND_WHEN("allocating a single frame")
+ {
+ auto result = allocator.allocate_many(1);
+
+ THEN("the result is not empty")
+ {
+ REQUIRE(result.has_value());
+ }
+ }
+
+ WHEN("allocating 0 frames")
+ {
+ auto result = allocator.allocate_many(0);
+
+ THEN("the result is empty")
+ {
+ REQUIRE_FALSE(result.has_value());
+ }
+ }
+ }
+ }
+
+ AND_GIVEN("an allocator with many single frame holes")
+ {
+ auto allocator = kernel::memory::bitmap_frame_allocator{std::span(storage), available_frames};
+ for (auto i = 0uz; i < available_frames; i += 2)
+ {
+ allocator.release_many({kapi::memory::frame{i}, 1});
+ }
+
+ WHEN("allocating 1 frame")
+ {
+ auto result = allocator.allocate_many(1);
+
+ THEN("the result is not empty")
+ {
+ REQUIRE(result.has_value());
+ }
+
+ THEN("the result contains 1 frame")
+ {
+ REQUIRE(result->second == 1);
+ }
+ }
+
+ WHEN("allocating 2 frames")
+ {
+ auto result = allocator.allocate_many(2);
+
+ THEN("the result is empty")
+ {
+ REQUIRE_FALSE(result.has_value());
+ }
+ }
+ }
+
+ AND_GIVEN("and allocator with all frames marked as free")
+ {
+ auto allocator = kernel::memory::bitmap_frame_allocator{std::span(storage), available_frames};
+ allocator.release_many({kapi::memory::frame{0}, available_frames});
+
+ WHEN("allocating 1 frame")
+ {
+ auto result = allocator.allocate_many(1);
+
+ THEN("the result is not empty")
+ {
+ REQUIRE(result.has_value());
+ }
+
+ THEN("the result contains 1 frame")
+ {
+ REQUIRE(result->second == 1);
+ }
+ }
+
+ WHEN("allocating multiple frames")
+ {
+ auto result = allocator.allocate_many(20);
+
+ THEN("the result is not empty")
+ {
+ REQUIRE(result.has_value());
+ }
+
+ THEN("the result contains 20 frames")
+ {
+ REQUIRE(result->second == 20);
+ }
+ }
+
+ WHEN("marking all frames as used")
+ {
+ for (auto i = 0uz; i < available_frames; i++)
+ {
+ allocator.mark_used(kapi::memory::frame{i});
+ }
+
+ THEN("the allocator has no free frames")
+ {
+ REQUIRE_FALSE(allocator.allocate_many(1).has_value());
+ }
+ }
+ }
+
+ AND_GIVEN("an allocator with a contiguous block of free frames")
+ {
+ auto allocator = kernel::memory::bitmap_frame_allocator{std::span(storage), available_frames};
+ allocator.release_many({kapi::memory::frame{0}, available_frames});
+ for (auto i = 0uz; i < available_frames / 2; i++)
+ {
+ allocator.mark_used(kapi::memory::frame{i});
+ }
+
+ WHEN("allocating a single frame")
+ {
+ auto result = allocator.allocate_many(1);
+
+ THEN("the result is not empty")
+ {
+ REQUIRE(result.has_value());
+ }
+
+ THEN("the result contains 1 frame")
+ {
+ REQUIRE(result->second == 1);
+ }
+ }
+
+ WHEN("allocating multiple frames")
+ {
+ auto result = allocator.allocate_many(20);
+
+ THEN("the result is not empty")
+ {
+ REQUIRE(result.has_value());
+ }
+
+ THEN("the result contains 20 frames")
+ {
+ REQUIRE(result->second == 20);
+ }
+ }
+ }
+ }
+} \ No newline at end of file
diff --git a/kernel/src/memory/block_list_allocator.cpp b/kernel/src/memory/block_list_allocator.cpp
index 5d870d8..6e68ada 100644
--- a/kernel/src/memory/block_list_allocator.cpp
+++ b/kernel/src/memory/block_list_allocator.cpp
@@ -1,24 +1,26 @@
-#include "kernel/memory/block_list_allocator.hpp"
+#include <kernel/memory/block_list_allocator.hpp>
-#include "kapi/memory.hpp"
-#include "kapi/system.hpp"
+#include <kernel/memory/heap_allocator.hpp>
-#include "kernel/memory/heap_allocator.hpp"
+#include <kapi/memory.hpp>
+#include <kapi/system.hpp>
#include <kstd/mutex>
+#include <kstd/units>
#include <bit>
#include <cstddef>
#include <cstdint>
#include <memory>
-#include <new>
+
+using namespace kstd::units_literals;
namespace kernel::memory
{
namespace
{
- [[nodiscard]] constexpr auto align_up(std::byte * pointer, std::align_val_t alignment) noexcept -> std::byte *
+ [[nodiscard]] constexpr auto align_up(std::byte * pointer, kstd::units::bytes alignment) noexcept -> std::byte *
{
auto const remainder = std::bit_cast<std::uintptr_t>(pointer) % static_cast<std::size_t>(alignment);
return remainder == 0 ? pointer : pointer + static_cast<std::size_t>(alignment) - remainder;
@@ -33,7 +35,7 @@ namespace kernel::memory
, m_lock{}
{}
- auto block_list_allocator::allocate(std::size_t size, std::align_val_t alignment) noexcept -> void *
+ auto block_list_allocator::allocate(kstd::units::bytes size, kstd::units::bytes alignment) noexcept -> void *
{
kstd::lock_guard guard{m_lock};
@@ -47,13 +49,13 @@ namespace kernel::memory
auto const raw_block = reinterpret_cast<std::byte *>(current);
auto const unaligned_payload = raw_block + allocated_metadata_size;
auto const aligned_payload = align_up(unaligned_payload, alignment);
- auto const required_padding = static_cast<std::size_t>(aligned_payload - unaligned_payload);
+ auto const required_padding = static_cast<kstd::units::bytes>(aligned_payload - unaligned_payload);
auto const total_required_size = required_padding + allocated_metadata_size + size;
if (current->usable_size >= total_required_size)
{
auto const payload_header = aligned_payload - sizeof(block_header *) - sizeof(block_header);
- auto const front_padding = static_cast<std::size_t>(payload_header - raw_block);
+ auto const front_padding = static_cast<kstd::units::bytes>(payload_header - raw_block);
auto payload_block = current;
@@ -72,9 +74,10 @@ namespace kernel::memory
payload_block->prev = current;
}
- auto const payload_size =
- aligned_payload - reinterpret_cast<std::byte *>(payload_block) - allocated_metadata_size + size;
- split(payload_block, payload_size, 0uz);
+ auto const header_size =
+ static_cast<kstd::units::bytes>(aligned_payload - reinterpret_cast<std::byte *>(payload_block));
+ auto const payload_size = header_size - allocated_metadata_size + size;
+ split(payload_block, payload_size, 0_B);
payload_block->free = false;
@@ -87,7 +90,7 @@ namespace kernel::memory
current = current->next;
}
- auto const search_size = size + static_cast<std::size_t>(alignment);
+ auto const search_size = size + alignment;
if (attempt == 0uz && !expand(search_size))
{
return nullptr;
@@ -114,10 +117,10 @@ namespace kernel::memory
coalesce(block);
}
- auto block_list_allocator::expand(std::size_t size) noexcept -> bool
+ auto block_list_allocator::expand(kstd::units::bytes size) noexcept -> bool
{
auto const total_required_size = size + allocated_metadata_size;
- auto const frames_needed = (total_required_size + kapi::memory::frame::size - 1) / kapi::memory::frame::size;
+ auto const frames_needed = (total_required_size + kapi::memory::frame::size - 1_B) / kapi::memory::frame::size;
auto const flags = kapi::memory::page_mapper::flags::writable | kapi::memory::page_mapper::flags::supervisor_only |
kapi::memory::page_mapper::flags::global;
@@ -187,7 +190,8 @@ namespace kernel::memory
}
}
- auto block_list_allocator::split(block_header * block, std::size_t size, std::size_t padding) noexcept -> void
+ auto block_list_allocator::split(block_header * block, kstd::units::bytes size, kstd::units::bytes padding) noexcept
+ -> void
{
auto const new_block_size = size + padding;
diff --git a/kernel/src/memory/block_list_allocator.tests.cpp b/kernel/src/memory/block_list_allocator.tests.cpp
new file mode 100644
index 0000000..c5f84c5
--- /dev/null
+++ b/kernel/src/memory/block_list_allocator.tests.cpp
@@ -0,0 +1,85 @@
+#include <kernel/memory/block_list_allocator.hpp>
+
+#include <kernel/test_support/memory.hpp>
+
+#include <kapi/memory.hpp>
+
+#include <kstd/units>
+
+#include <catch2/catch_test_macros.hpp>
+
+#include <cstddef>
+
+using namespace kstd::units_literals;
+
+SCENARIO("Block List Allocator Operations", "[memory][allocator]")
+{
+ GIVEN("A newly initialized block list allocator mapped via the test sandbox")
+ {
+ kernel::tests::memory::deinit();
+ kapi::memory::init();
+
+ auto sandbox_base = kernel::tests::memory::virtual_base();
+ kernel::memory::block_list_allocator allocator{sandbox_base};
+
+ WHEN("a basic allocation request is made")
+ {
+ void * ptr = allocator.allocate(128_B, 8_B);
+
+ THEN("a valid, non-null pointer is returned")
+ {
+ REQUIRE(ptr != nullptr);
+ }
+
+ AND_THEN("the returned memory is writeable without causing segmentation faults")
+ {
+ auto byte_ptr = static_cast<std::byte *>(ptr);
+ byte_ptr[0] = std::byte{0xDE};
+ byte_ptr[127] = std::byte{0xAD};
+ REQUIRE(byte_ptr[0] == std::byte{0xDE});
+ REQUIRE(byte_ptr[127] == std::byte{0xAD});
+ }
+
+ allocator.deallocate(ptr);
+ }
+
+ WHEN("multiple allocations are made sequentially")
+ {
+ void * ptr1 = allocator.allocate(64_B, 8_B);
+ void * ptr2 = allocator.allocate(64_B, 8_B);
+ void * ptr3 = allocator.allocate(1_KiB, 16_B);
+
+ THEN("they return distinct, non-overlapping memory blocks")
+ {
+ REQUIRE(ptr1 != nullptr);
+ REQUIRE(ptr2 != nullptr);
+ REQUIRE(ptr3 != nullptr);
+ REQUIRE(ptr1 != ptr2);
+ REQUIRE(ptr2 != ptr3);
+ REQUIRE(ptr1 != ptr3);
+ }
+
+ allocator.deallocate(ptr1);
+ allocator.deallocate(ptr2);
+ allocator.deallocate(ptr3);
+ }
+
+ WHEN("a block is allocated and then completely freed")
+ {
+ void * original_ptr = allocator.allocate(512_B, 16_B);
+ allocator.deallocate(original_ptr);
+
+ AND_WHEN("a new allocation of equal or smaller size is requested")
+ {
+ void * new_ptr = allocator.allocate(128_B, 16_B);
+
+ THEN("the allocator actively reuses the coalesced space")
+ {
+ REQUIRE(new_ptr == original_ptr);
+ }
+
+ allocator.deallocate(new_ptr);
+ }
+ }
+ }
+}
diff --git a/kernel/src/memory/mmio_allocator.cpp b/kernel/src/memory/mmio_allocator.cpp
new file mode 100644
index 0000000..ba23dbd
--- /dev/null
+++ b/kernel/src/memory/mmio_allocator.cpp
@@ -0,0 +1,111 @@
+#include <kernel/memory/mmio_allocator.hpp>
+
+#include <kapi/memory.hpp>
+#include <kapi/system.hpp>
+
+#include <kstd/allocator>
+
+#include <cstddef>
+#include <memory>
+#include <utility>
+
+namespace kernel::memory
+{
+
+ mmio_allocator::mmio_allocator(kapi::memory::linear_address base, std::size_t pages)
+ : m_head{make_node(base, pages, nullptr, nullptr, true)}
+ {}
+
+ auto mmio_allocator::allocate(std::size_t count) -> kapi::memory::linear_address
+ {
+ if (count == 0 || !m_head)
+ {
+ return {};
+ }
+
+ auto current = m_head;
+ while (current)
+ {
+ if (current->is_free && current->page_count >= count)
+ {
+ if (current->page_count > count)
+ {
+ auto new_base = current->base + (count * kapi::memory::page::size);
+ auto split_node = make_node(new_base, current->page_count - count, std::move(current->next), current, true);
+
+ if (current->next)
+ {
+ current->next->previous = split_node;
+ }
+ current->next = split_node;
+ current->page_count = count;
+ }
+
+ current->is_free = false;
+ return current->base;
+ }
+ current = current->next;
+ }
+
+ kapi::system::panic("[OS:MEM] MMIO alloctor out of memory!");
+ return {};
+ }
+
+ auto mmio_allocator::release(kapi::memory::linear_address base) -> void
+ {
+ auto current = m_head;
+
+ while (current)
+ {
+ if (current->base == base && !current->is_free)
+ {
+ current->is_free = true;
+
+ if (current->next && current->next->is_free)
+ {
+ auto removed = current->next;
+ current->page_count += removed->page_count;
+ current->next = removed->next;
+ if (current->next)
+ {
+ current->next->previous = current;
+ }
+ destroy_node(removed);
+ }
+
+ if (current->previous && current->previous->is_free)
+ {
+ auto removed = current;
+ removed->previous->page_count += removed->page_count;
+ removed->previous->next = removed->next;
+ if (removed->next)
+ {
+ removed->next->previous = removed->previous;
+ }
+ destroy_node(removed);
+ }
+ return;
+ }
+ current = current->next;
+ }
+ }
+
+ auto mmio_allocator::make_node(kapi::memory::linear_address base, std::size_t page_count, node * next,
+ node * previous, bool is_free) -> node *
+ {
+ using traits = std::allocator_traits<kstd::allocator<node>>;
+
+ auto new_node = traits::allocate(m_allocator, 1);
+ traits::construct(m_allocator, new_node, base, page_count, next, previous, is_free);
+ return new_node;
+ }
+
+ auto mmio_allocator::destroy_node(node * instance) -> void
+ {
+ using traits = std::allocator_traits<kstd::allocator<node>>;
+
+ traits::destroy(m_allocator, instance);
+ traits::deallocate(m_allocator, instance, 1);
+ }
+
+} // namespace kernel::memory
diff --git a/kernel/src/memory/operators.cpp b/kernel/src/memory/operators.cpp
index 57e31e6..5673d68 100644
--- a/kernel/src/memory/operators.cpp
+++ b/kernel/src/memory/operators.cpp
@@ -1,6 +1,8 @@
-#include "kapi/system.hpp"
+#include <kernel/memory.hpp>
-#include "kernel/memory.hpp"
+#include <kapi/system.hpp>
+
+#include <kstd/units>
#include <cstddef>
#include <new>
@@ -8,7 +10,8 @@
[[nodiscard]] auto operator new(std::size_t size, std::align_val_t alignment, std::nothrow_t const &) noexcept -> void *
{
auto & allocator = kernel::memory::get_heap_allocator();
- return allocator.allocate(size, alignment);
+ return allocator.allocate(static_cast<kstd::units::bytes>(size),
+ static_cast<kstd::units::bytes>(static_cast<std::size_t>(alignment)));
}
[[nodiscard]] auto operator new(std::size_t size, std::align_val_t alignment) -> void *
@@ -73,9 +76,9 @@ auto operator delete(void * pointer, std::align_val_t) noexcept -> void
::operator delete(pointer);
}
-auto operator delete(void * pointer, std::size_t, std::align_val_t) noexcept -> void
+auto operator delete(void * pointer, std::size_t size, std::align_val_t) noexcept -> void
{
- ::operator delete(pointer);
+ ::operator delete(pointer, size);
}
auto operator delete[](void * pointer) noexcept -> void
@@ -83,9 +86,9 @@ auto operator delete[](void * pointer) noexcept -> void
::operator delete(pointer);
}
-auto operator delete[](void * pointer, std::size_t) noexcept -> void
+auto operator delete[](void * pointer, std::size_t size) noexcept -> void
{
- ::operator delete(pointer);
+ ::operator delete(pointer, size);
}
auto operator delete[](void * pointer, std::align_val_t) noexcept -> void
@@ -93,7 +96,7 @@ auto operator delete[](void * pointer, std::align_val_t) noexcept -> void
::operator delete(pointer);
}
-auto operator delete[](void * pointer, std::size_t, std::align_val_t) noexcept -> void
+auto operator delete[](void * pointer, std::size_t size, std::align_val_t) noexcept -> void
{
- ::operator delete(pointer);
+ ::operator delete(pointer, size);
}
diff --git a/kernel/src/test_support/devices/block_device.cpp b/kernel/src/test_support/devices/block_device.cpp
new file mode 100644
index 0000000..9a9e544
--- /dev/null
+++ b/kernel/src/test_support/devices/block_device.cpp
@@ -0,0 +1,61 @@
+#include <kernel/test_support/devices/block_device.hpp>
+
+#include <kernel/devices/block_device.hpp>
+
+#include <kstd/string>
+#include <kstd/vector>
+
+#include <algorithm>
+#include <cstddef>
+#include <cstdint>
+#include <cstring>
+#include <string.h>
+
+namespace kernel::tests::devices
+{
+ block_device::block_device(size_t major, size_t minor, kstd::string const & name, size_t block_size,
+ size_t initial_size)
+ : kernel::devices::block_device(major, minor, name, block_size)
+ {
+ data.resize(initial_size, 0);
+ }
+
+ auto block_device::init() -> bool
+ {
+ return true;
+ }
+
+ auto block_device::read_block(size_t block_index, void * buffer) const -> void
+ {
+ auto const offset = block_index * block_size();
+ if (offset >= data.size())
+ {
+ kstd::libc::memset(buffer, 0, block_size());
+ return;
+ }
+
+ auto const bytes_to_read = std::min(block_size(), data.size() - offset);
+ kstd::libc::memcpy(buffer, data.data() + offset, bytes_to_read);
+ if (bytes_to_read < block_size())
+ {
+ kstd::libc::memset(static_cast<uint8_t *>(buffer) + bytes_to_read, 0, block_size() - bytes_to_read);
+ }
+ }
+
+ auto block_device::write_block(size_t block_index, void const * buffer) -> void
+ {
+ auto const offset = block_index * block_size();
+ auto const write_end = offset + block_size();
+ if (write_end > data.size())
+ {
+ data.resize(write_end, 0);
+ }
+
+ kstd::libc::memcpy(data.data() + offset, static_cast<uint8_t const *>(buffer), block_size());
+ }
+
+ auto block_device::size() const -> size_t
+ {
+ return data.size();
+ }
+} // namespace kernel::tests::devices \ No newline at end of file
diff --git a/kernel/src/test_support/devices/character_device.cpp b/kernel/src/test_support/devices/character_device.cpp
new file mode 100644
index 0000000..3806654
--- /dev/null
+++ b/kernel/src/test_support/devices/character_device.cpp
@@ -0,0 +1,19 @@
+#include <kernel/test_support/devices/character_device.hpp>
+
+#include <kapi/devices.hpp>
+
+#include <kstd/string>
+
+#include <cstddef>
+
+namespace kernel::tests::devices
+{
+ character_device::character_device(size_t major, size_t minor, kstd::string const & name)
+ : kapi::devices::device(major, minor, name)
+ {}
+
+ auto character_device::init() -> bool
+ {
+ return true;
+ }
+} // namespace kernel::tests::devices \ No newline at end of file
diff --git a/kernel/src/test_support/filesystem/ext2.cpp b/kernel/src/test_support/filesystem/ext2.cpp
new file mode 100644
index 0000000..52b6efe
--- /dev/null
+++ b/kernel/src/test_support/filesystem/ext2.cpp
@@ -0,0 +1,68 @@
+#include <kernel/test_support/filesystem/ext2.hpp>
+
+#include <kernel/filesystem/ext2/block_group_descriptor.hpp>
+#include <kernel/filesystem/ext2/filesystem.hpp>
+#include <kernel/filesystem/ext2/inode.hpp>
+#include <kernel/filesystem/ext2/superblock.hpp>
+#include <kernel/test_support/devices/block_device.hpp>
+
+#include <cstdint>
+#include <cstring>
+
+namespace kernel::tests::filesystem::ext2
+{
+ namespace
+ {
+ constexpr uint32_t root_directory_data_block = 20;
+ } // namespace
+
+ auto write_bytes(kernel::tests::devices::block_device & device, size_t offset, void const * source, size_t size)
+ -> void
+ {
+ auto const required_size = offset + size;
+ if (device.data.size() < required_size)
+ {
+ device.data.resize(required_size, 0);
+ }
+
+ std::memcpy(device.data.data() + offset, source, size);
+ }
+
+ auto write_u32(kernel::tests::devices::block_device & device, size_t offset, uint32_t value) -> void
+ {
+ write_bytes(device, offset, &value, sizeof(value));
+ }
+
+ auto setup_mock_ext2_layout(kernel::tests::devices::block_device & device) -> void
+ {
+ auto superblock = kernel::filesystem::ext2::superblock{};
+ superblock.magic = kernel::filesystem::ext2::constants::magic_number;
+ superblock.log_block_size = 0;
+ superblock.blocks_count = 64;
+ superblock.blocks_per_group = 64;
+ superblock.inodes_per_group = 32;
+ superblock.rev_level = 1;
+ superblock.inode_size = 128;
+ setup_mock_ext2_layout(device, superblock);
+ }
+
+ auto setup_mock_ext2_layout(kernel::tests::devices::block_device & device,
+ kernel::filesystem::ext2::superblock const & superblock) -> void
+ {
+ write_bytes(device, kernel::filesystem::ext2::constants::superblock_offset, &superblock, sizeof(superblock));
+
+ auto group_descriptor = kernel::filesystem::ext2::block_group_descriptor{};
+ group_descriptor.inode_table = 5;
+ write_bytes(device, 2048, &group_descriptor, sizeof(group_descriptor));
+
+ auto root_inode_data = kernel::filesystem::ext2::inode_data{};
+ root_inode_data.mode = kernel::filesystem::ext2::constants::mode_directory;
+ root_inode_data.blocks = 2;
+ root_inode_data.block[0] = root_directory_data_block;
+
+ auto const root_inode_offset =
+ static_cast<size_t>(group_descriptor.inode_table) * kernel::filesystem::ext2::constants::base_block_size +
+ (kernel::filesystem::ext2::constants::root_inode_number - 1) * superblock.inode_size;
+ write_bytes(device, root_inode_offset, &root_inode_data, sizeof(root_inode_data));
+ }
+} // namespace kernel::tests::filesystem::ext2 \ No newline at end of file
diff --git a/kernel/src/test_support/filesystem/filesystem.cpp b/kernel/src/test_support/filesystem/filesystem.cpp
new file mode 100644
index 0000000..ec70607
--- /dev/null
+++ b/kernel/src/test_support/filesystem/filesystem.cpp
@@ -0,0 +1,17 @@
+#include <kernel/test_support/filesystem/filesystem.hpp>
+
+#include <kernel/filesystem/inode.hpp>
+#include <kernel/test_support/filesystem/inode.hpp>
+
+#include <kstd/memory>
+
+#include <string_view>
+
+namespace kernel::tests::filesystem
+{
+ auto filesystem::lookup(kstd::shared_ptr<kernel::filesystem::inode> const &, std::string_view) const
+ -> kstd::shared_ptr<kernel::filesystem::inode>
+ {
+ return kstd::make_shared<inode>();
+ }
+} // namespace kernel::tests::filesystem \ No newline at end of file
diff --git a/kernel/src/test_support/filesystem/inode.cpp b/kernel/src/test_support/filesystem/inode.cpp
new file mode 100644
index 0000000..0c8d956
--- /dev/null
+++ b/kernel/src/test_support/filesystem/inode.cpp
@@ -0,0 +1,23 @@
+#include <kernel/test_support/filesystem/inode.hpp>
+
+#include <kernel/filesystem/inode.hpp>
+
+#include <cstddef>
+
+namespace kernel::tests::filesystem
+{
+ auto inode::read(void *, size_t, size_t size) const -> size_t
+ {
+ return size;
+ }
+
+ auto inode::write(void const *, size_t, size_t size) -> size_t
+ {
+ return size;
+ }
+
+ auto inode::is_regular() const -> bool
+ {
+ return true;
+ }
+} // namespace kernel::tests::filesystem \ No newline at end of file
diff --git a/kernel/src/test_support/filesystem/storage_boot_module_fixture.cpp b/kernel/src/test_support/filesystem/storage_boot_module_fixture.cpp
new file mode 100644
index 0000000..aabaace
--- /dev/null
+++ b/kernel/src/test_support/filesystem/storage_boot_module_fixture.cpp
@@ -0,0 +1,139 @@
+#include <kernel/test_support/filesystem/storage_boot_module_fixture.hpp>
+
+#include <kernel/devices/storage/management.hpp>
+#include <kernel/test_support/boot_modules.hpp>
+#include <kernel/test_support/devices/storage/management.hpp>
+
+#include <kapi/boot_module/boot_module.hpp>
+#include <kapi/boot_modules.hpp>
+#include <kapi/memory.hpp>
+
+#include <cstddef>
+#include <fcntl.h>
+#include <filesystem>
+#include <format>
+#include <stdexcept>
+#include <string>
+#include <unistd.h>
+#include <utility>
+#include <vector>
+
+#include <sys/mman.h>
+#include <sys/stat.h>
+
+namespace kernel::tests::filesystem
+{
+ storage_boot_module_fixture::mapped_image::mapped_image(std::filesystem::path path)
+ : file_descriptor(::open(path.c_str(), O_RDWR))
+ {
+ if (file_descriptor < 0)
+ {
+ throw std::runtime_error{"Failed to open image file for test boot module: " + path.string()};
+ }
+
+ struct stat statistics{};
+ if (::fstat(file_descriptor, &statistics) < 0)
+ {
+ throw std::runtime_error{"Failed to get statistics for image file: " + path.string()};
+ }
+
+ size = static_cast<std::size_t>(statistics.st_size);
+
+ mapping = static_cast<std::byte *>(::mmap(nullptr, size, PROT_READ | PROT_WRITE, MAP_PRIVATE, file_descriptor, 0));
+ if (mapping == MAP_FAILED)
+ {
+ throw std::runtime_error{"Failed to map image file for test boot module: " + path.string()};
+ }
+ }
+
+ storage_boot_module_fixture::mapped_image::~mapped_image()
+ {
+ if (mapping != nullptr)
+ {
+ ::munmap(mapping, size);
+ }
+ if (file_descriptor >= 0)
+ {
+ ::close(file_descriptor);
+ }
+ }
+
+ storage_boot_module_fixture::mapped_image::mapped_image(mapped_image && other) noexcept
+ : file_descriptor{std::exchange(other.file_descriptor, -1)}
+ , mapping{std::exchange(other.mapping, nullptr)}
+ , size{std::exchange(other.size, 0)}
+ {}
+
+ auto storage_boot_module_fixture::mapped_image::operator=(mapped_image && other) noexcept -> mapped_image &
+ {
+ if (this != &other)
+ {
+ file_descriptor = std::exchange(other.file_descriptor, -1);
+ mapping = std::exchange(other.mapping, nullptr);
+ size = std::exchange(other.size, 0);
+ }
+ return *this;
+ }
+
+ storage_boot_module_fixture::~storage_boot_module_fixture()
+ {
+ kernel::tests::devices::storage::management::deinit();
+ kernel::tests::boot_modules::deinit();
+ }
+
+ auto storage_boot_module_fixture::setup_modules(std::size_t module_count, std::size_t module_size) -> void
+ {
+ m_module_names.clear();
+ m_module_data.clear();
+ m_registry = {};
+
+ m_module_names.reserve(module_count);
+ m_module_data.reserve(module_count);
+
+ for (std::size_t i = 0; i < module_count; ++i)
+ {
+ m_module_names.push_back(std::format("test_mod{}", i));
+ m_module_data.emplace_back(module_size, std::byte{static_cast<unsigned char>(0x40 + (i % 16))});
+ }
+
+ for (std::size_t i = 0; i < module_count; ++i)
+ {
+ m_registry.add_boot_module(kapi::boot_modules::boot_module{
+ m_module_names[i].c_str(), kapi::memory::linear_address{m_module_data[i].data()}, m_module_data[i].size()});
+ }
+
+ kapi::boot_modules::set_boot_module_registry(m_registry);
+ kernel::devices::storage::management::init();
+ }
+
+ auto storage_boot_module_fixture::setup_modules_from_img(std::vector<std::string> const & module_names,
+ std::vector<std::filesystem::path> const & img_paths) -> void
+ {
+ m_module_names.clear();
+ m_module_data.clear();
+ m_registry = {};
+
+ if (module_names.size() != img_paths.size())
+ {
+ throw std::invalid_argument{"Module names and image paths vectors must have the same size."};
+ }
+
+ for (size_t i = 0; i < module_names.size(); ++i)
+ {
+ setup_module_from_img(module_names[i], img_paths[i]);
+ }
+
+ kapi::boot_modules::set_boot_module_registry(m_registry);
+ kernel::devices::storage::management::init();
+ }
+
+ auto storage_boot_module_fixture::setup_module_from_img(std::string const & module_name,
+ std::filesystem::path const & img_path) -> void
+ {
+ m_module_names.push_back(module_name);
+ auto & mapped_image = m_mapped_images.emplace_back(img_path);
+
+ m_registry.add_boot_module(kapi::boot_modules::boot_module{
+ m_module_names.back().c_str(), kapi::memory::linear_address{mapped_image.mapping}, mapped_image.size});
+ }
+} // namespace kernel::tests::filesystem \ No newline at end of file
diff --git a/kernel/src/test_support/filesystem/storage_boot_module_vfs_fixture.cpp b/kernel/src/test_support/filesystem/storage_boot_module_vfs_fixture.cpp
new file mode 100644
index 0000000..02ccfec
--- /dev/null
+++ b/kernel/src/test_support/filesystem/storage_boot_module_vfs_fixture.cpp
@@ -0,0 +1,31 @@
+#include <kernel/test_support/filesystem/storage_boot_module_vfs_fixture.hpp>
+
+#include <kernel/filesystem/vfs.hpp>
+#include <kernel/test_support/filesystem/vfs.hpp>
+
+#include <cstddef>
+#include <filesystem>
+#include <string>
+#include <vector>
+
+namespace kernel::tests::filesystem
+{
+ storage_boot_module_vfs_fixture::~storage_boot_module_vfs_fixture()
+ {
+ kernel::tests::filesystem::vfs::deinit();
+ }
+
+ auto storage_boot_module_vfs_fixture::setup_modules_and_init_vfs(std::size_t module_count, std::size_t module_size)
+ -> void
+ {
+ setup_modules(module_count, module_size);
+ kernel::filesystem::vfs::init();
+ }
+
+ auto storage_boot_module_vfs_fixture::setup_modules_from_img_and_init_vfs(
+ std::vector<std::string> const & module_names, std::vector<std::filesystem::path> const & img_paths) -> void
+ {
+ setup_modules_from_img(module_names, img_paths);
+ kernel::filesystem::vfs::init();
+ }
+} // namespace kernel::tests::filesystem \ No newline at end of file
diff --git a/kernel/src/test_support/filesystem/test_assets/README.md b/kernel/src/test_support/filesystem/test_assets/README.md
new file mode 120000
index 0000000..718a227
--- /dev/null
+++ b/kernel/src/test_support/filesystem/test_assets/README.md
@@ -0,0 +1 @@
+/arch/x86_64/support/modules/README.md \ No newline at end of file
diff --git a/kernel/src/test_support/filesystem/test_assets/ext2_1KB_fs.img b/kernel/src/test_support/filesystem/test_assets/ext2_1KB_fs.img
new file mode 100644
index 0000000..a5202ca
--- /dev/null
+++ b/kernel/src/test_support/filesystem/test_assets/ext2_1KB_fs.img
@@ -0,0 +1,3 @@
+version https://git-lfs.github.com/spec/v1
+oid sha256:98ac3c1be872806e25fb14eea168ca79a91959f4e6a5ac3d00c5d8224c1f73a3
+size 10485760
diff --git a/kernel/src/test_support/filesystem/test_assets/ext2_2KB_fs.img b/kernel/src/test_support/filesystem/test_assets/ext2_2KB_fs.img
new file mode 100644
index 0000000..7f297f0
--- /dev/null
+++ b/kernel/src/test_support/filesystem/test_assets/ext2_2KB_fs.img
@@ -0,0 +1,3 @@
+version https://git-lfs.github.com/spec/v1
+oid sha256:6d9e872916e7d9107b321cc007e151899d5f19400a694666c0b24d482aef61ca
+size 5242880
diff --git a/kernel/src/test_support/filesystem/test_assets/ext2_4KB_fs.img b/kernel/src/test_support/filesystem/test_assets/ext2_4KB_fs.img
new file mode 100644
index 0000000..c3f6daf
--- /dev/null
+++ b/kernel/src/test_support/filesystem/test_assets/ext2_4KB_fs.img
@@ -0,0 +1,3 @@
+version https://git-lfs.github.com/spec/v1
+oid sha256:026ca30269dbd80beb2dd74677c94676d1d4a7f6b5fe406c4ddb82836ba2dc00
+size 10485760
diff --git a/kernel/src/test_support/kapi/cio.cpp b/kernel/src/test_support/kapi/cio.cpp
new file mode 100644
index 0000000..98bc99d
--- /dev/null
+++ b/kernel/src/test_support/kapi/cio.cpp
@@ -0,0 +1,54 @@
+#include <kernel/test_support/cio.hpp>
+
+#include <kernel/test_support/log_buffer.hpp>
+
+#include <kapi/cio.hpp>
+
+#include <atomic>
+#include <optional>
+#include <stdexcept>
+
+namespace
+{
+
+ auto constinit is_initialized = std::atomic_flag{};
+ auto constinit device = std::optional<kernel::tests::cio::output_device>{};
+
+} // namespace
+
+namespace kapi::cio
+{
+
+ auto init() -> void
+ {
+ if (is_initialized.test_and_set())
+ {
+ throw std::logic_error("kapi::cio::init() called more than once");
+ }
+
+ device.emplace();
+ set_output_device(*device);
+ }
+
+} // namespace kapi::cio
+
+namespace kernel::tests::cio
+{
+
+ auto deinit() -> void
+ {
+ if (!is_initialized.test())
+ {
+ throw std::logic_error("kapi::cio::deinit() called before kapi::cio::init()");
+ }
+
+ device.reset();
+ is_initialized.clear();
+ }
+
+ auto log_buffer() -> kernel::tests::log_buffer &
+ {
+ return device->log_buffer();
+ }
+
+} // namespace kernel::tests::cio \ No newline at end of file
diff --git a/kernel/src/test_support/kapi/cpu.cpp b/kernel/src/test_support/kapi/cpu.cpp
new file mode 100644
index 0000000..5d95633
--- /dev/null
+++ b/kernel/src/test_support/kapi/cpu.cpp
@@ -0,0 +1,52 @@
+#include <kernel/test_support/cpu.hpp>
+
+#include <kapi/cpu.hpp>
+
+#include <atomic>
+#include <stdexcept>
+
+namespace
+{
+ auto static initialized = std::atomic_flag{};
+}
+
+namespace kapi::cpu
+{
+
+ auto init() -> void
+ {
+ if (initialized.test_and_set())
+ {
+ throw std::logic_error("kapi::cpu::init() called more than once");
+ }
+
+ // TODO: make sure that simulated interrupt can run.
+ }
+
+ auto halt() -> void
+ {
+ throw kernel::tests::cpu::halt{};
+ }
+
+ auto discover_topology() -> bool
+ {
+ // TODO: implement more meaningful simulated CPU topology discovery
+ return true;
+ }
+
+} // namespace kapi::cpu
+
+namespace kernel::tests::cpu
+{
+
+ auto deinit() -> void
+ {
+ if (!initialized.test())
+ {
+ throw std::logic_error{"kapi::cpu::reset() called before kapi::cpu::init()"};
+ }
+
+ initialized.clear();
+ }
+
+} // namespace kernel::tests::cpu \ No newline at end of file
diff --git a/kernel/src/test_support/kapi/interrupts.cpp b/kernel/src/test_support/kapi/interrupts.cpp
new file mode 100644
index 0000000..0077266
--- /dev/null
+++ b/kernel/src/test_support/kapi/interrupts.cpp
@@ -0,0 +1,11 @@
+#include <kapi/interrupts.hpp>
+
+namespace kapi::interrupts
+{
+
+ auto enable() -> void
+ {
+ // TODO: enable simulated interrupts.
+ }
+
+} // namespace kapi::interrupts \ No newline at end of file
diff --git a/kernel/src/test_support/kapi/memory.cpp b/kernel/src/test_support/kapi/memory.cpp
new file mode 100644
index 0000000..7fc95cb
--- /dev/null
+++ b/kernel/src/test_support/kapi/memory.cpp
@@ -0,0 +1,74 @@
+#include <kapi/memory.hpp>
+
+#include <kernel/test_support/bump_frame_allocator.hpp>
+#include <kernel/test_support/page_mapper.hpp>
+
+#include <kapi/memory.hpp>
+
+#include <kstd/units>
+
+#include <optional>
+
+namespace
+{
+ //! The size of the simulated RAM.
+ constexpr auto physical_size = kstd::units::MiB(32);
+ constexpr auto virtual_size = kstd::units::GiB(1);
+
+ constexpr auto number_of_frames = physical_size / kapi::memory::frame::size;
+
+ auto constinit bump_allocator = std::optional<kernel::tests::bump_frame_allocator>{};
+ auto constinit test_mapper = std::optional<kernel::tests::page_mapper>{};
+
+ auto constinit old_allocator = std::optional<kapi::memory::frame_allocator *>{};
+ auto constinit old_mapper = std::optional<kapi::memory::page_mapper *>{};
+
+ auto handoff_to_kernel_pmm(kapi::memory::frame_allocator & new_allocator) -> void
+ {
+ auto first_free_frame = bump_allocator->next_free_frame;
+ auto number_of_free_frames = number_of_frames - first_free_frame;
+ new_allocator.release_many({kapi::memory::frame{first_free_frame}, number_of_free_frames});
+ }
+
+} // namespace
+
+namespace kapi::memory
+{
+
+ auto init() -> void
+ {
+ bump_allocator.emplace();
+ test_mapper.emplace(physical_size, virtual_size);
+
+ old_allocator = set_frame_allocator(*bump_allocator);
+ old_mapper = set_page_mapper(*test_mapper);
+
+ init_pmm(physical_size / frame::size, handoff_to_kernel_pmm);
+ }
+} // namespace kapi::memory
+
+namespace kernel::tests::memory
+{
+
+ auto deinit() -> void
+ {
+ if (old_allocator && *old_allocator)
+ {
+ set_frame_allocator(**old_allocator);
+ }
+
+ if (old_mapper && *old_mapper)
+ {
+ set_page_mapper(**old_mapper);
+ }
+
+ bump_allocator.reset();
+ test_mapper.reset();
+ }
+
+ auto virtual_base() -> kapi::memory::linear_address
+ {
+ return test_mapper->memory.virtual_base();
+ }
+
+} // namespace kernel::tests::memory \ No newline at end of file
diff --git a/kernel/src/test_support/log_buffer.cpp b/kernel/src/test_support/log_buffer.cpp
new file mode 100644
index 0000000..04d875b
--- /dev/null
+++ b/kernel/src/test_support/log_buffer.cpp
@@ -0,0 +1,33 @@
+#include <kernel/test_support/log_buffer.hpp>
+
+#include <algorithm>
+#include <string>
+#include <vector>
+
+namespace kernel::tests
+{
+
+ auto log_buffer::append(std::string const & message) -> void
+ {
+ m_messages.push_back(message);
+ }
+
+ auto log_buffer::clear() -> void
+ {
+ m_messages.clear();
+ }
+
+ auto log_buffer::flat_messages() -> std::string
+ {
+ return std::ranges::fold_left(m_messages, std::string{}, [](std::string accumulator, std::string const & message) {
+ accumulator += message;
+ return accumulator;
+ });
+ }
+
+ auto log_buffer::messages() -> std::vector<std::string> const &
+ {
+ return m_messages;
+ }
+
+} // namespace kernel::tests
diff --git a/kernel/src/test_support/output_device.cpp b/kernel/src/test_support/output_device.cpp
new file mode 100644
index 0000000..45fb4bc
--- /dev/null
+++ b/kernel/src/test_support/output_device.cpp
@@ -0,0 +1,28 @@
+#include <kernel/test_support/cio.hpp>
+#include <kernel/test_support/log_buffer.hpp>
+
+#include <kapi/cio.hpp>
+
+#include <iostream>
+#include <string>
+#include <string_view>
+
+namespace kernel::tests::cio
+{
+
+ auto output_device::write(kapi::cio::output_stream stream, std::string_view text) -> void
+ {
+ auto & standard_stream = stream == kapi::cio::output_stream::stdout ? std::cout : std::cerr;
+ standard_stream << text;
+ if (text != "\n")
+ {
+ m_log_buffer.append(std::string{text});
+ }
+ }
+
+ auto output_device::log_buffer() noexcept -> kernel::tests::log_buffer &
+ {
+ return m_log_buffer;
+ }
+
+} // namespace kernel::tests::cio \ No newline at end of file
diff --git a/kernel/src/test_support/page_mapper.cpp b/kernel/src/test_support/page_mapper.cpp
new file mode 100644
index 0000000..3d50ff1
--- /dev/null
+++ b/kernel/src/test_support/page_mapper.cpp
@@ -0,0 +1,70 @@
+#include <kernel/test_support/page_mapper.hpp>
+
+#include <kapi/memory.hpp>
+
+#include <kstd/units>
+
+#include <cstddef>
+#include <format>
+#include <stdexcept>
+
+namespace kernel::tests
+{
+
+ page_mapper::page_mapper(kstd::units::bytes physical_size, kstd::units::bytes virtual_size)
+ : memory{physical_size, virtual_size}
+ {}
+
+ auto page_mapper::map(kapi::memory::page page, kapi::memory::frame frame, flags) -> std::byte *
+ {
+ auto result = page_mappings.insert({page.number(), frame});
+ if (!result.second)
+ {
+ auto error = std::format("Page {} was already mapped!", page.number());
+ throw std::invalid_argument{error};
+ }
+
+ auto page_address = page.start_address();
+ auto virtual_base = memory.virtual_base();
+ auto virtual_end = virtual_base + memory.virtual_size();
+
+ if (page_address >= virtual_base && page_address < virtual_end)
+ {
+ auto virtual_target = static_cast<std::byte *>(page_address);
+ auto physical_offset = frame.number() * kapi::memory::frame::size;
+ return memory.map(kapi::memory::page::size, virtual_target, physical_offset.value);
+ }
+ else if (page_address >= kapi::memory::mmio_base)
+ {
+ throw std::runtime_error("MMIO mapping not yet supported in testing!");
+ }
+ else if (page_address >= kapi::memory::higher_half_direct_map_base)
+ {
+ auto offset = frame.number() * kapi::memory::frame::size;
+ return memory.physical_base() + offset;
+ }
+
+ return nullptr;
+ }
+
+ auto page_mapper::unmap(kapi::memory::page page) -> void
+ {
+ if (!try_unmap(page))
+ {
+ auto error = std::format("Page {} was never mapped!", page.number());
+ throw std::invalid_argument{error};
+ }
+ }
+
+ auto page_mapper::try_unmap(kapi::memory::page page) noexcept -> bool
+ {
+ if (page_mappings.contains(page.number()))
+ {
+ page_mappings.erase(page.number());
+ return true;
+ }
+
+ return false;
+ }
+
+} // namespace kernel::tests \ No newline at end of file
diff --git a/kernel/src/test_support/simulated_memory.cpp b/kernel/src/test_support/simulated_memory.cpp
new file mode 100644
index 0000000..074e6b1
--- /dev/null
+++ b/kernel/src/test_support/simulated_memory.cpp
@@ -0,0 +1,106 @@
+#include <kernel/test_support/simulated_memory.hpp>
+
+#include <kapi/memory.hpp>
+
+#include <kstd/units>
+
+#include <cerrno>
+#include <cstddef>
+#include <cstring>
+#include <format>
+#include <stdexcept>
+#include <unistd.h>
+
+#include <sys/mman.h>
+#include <sys/types.h>
+
+namespace kernel::tests
+{
+
+ simulated_memory::simulated_memory(kstd::units::bytes physical_size, kstd::units::bytes virtual_size)
+ : m_descriptor{memfd_create("teachos_simulated_memory", 0)}
+ , m_physical_size{physical_size}
+ , m_virtual_size{virtual_size}
+ {
+ if (m_descriptor < 0)
+ {
+ auto error = std::format("Failed to allocate backing memory: {}", strerror(errno));
+ throw std::runtime_error(error);
+ }
+
+ if (ftruncate(m_descriptor, static_cast<off_t>(m_physical_size.value)) < 0)
+ {
+ auto error = std::format("Failed to reserve backing memory: {}", strerror(errno));
+ throw std::runtime_error(error);
+ }
+
+ auto physical_storage = mmap(nullptr, m_physical_size.value, PROT_READ | PROT_WRITE, MAP_SHARED, m_descriptor, 0);
+ if (physical_storage == MAP_FAILED)
+ {
+ auto error = std::format("Failed to map backing memory: {}", strerror(errno));
+ throw std::runtime_error(error);
+ }
+
+ auto virtual_pointer = mmap(nullptr, virtual_size.value, PROT_NONE, MAP_PRIVATE | MAP_ANONYMOUS, -1, 0);
+ if (virtual_pointer == MAP_FAILED)
+ {
+ auto error = std::format("Failed to reserve virtual memory: {}", strerror(errno));
+ throw std::runtime_error(error);
+ }
+
+ m_physical_base = static_cast<std::byte *>(physical_storage);
+ m_virtual_base = static_cast<std::byte *>(virtual_pointer);
+
+ clear();
+ }
+
+ simulated_memory::~simulated_memory()
+ {
+ munmap(m_virtual_base, m_virtual_size.value);
+ munmap(m_physical_base, m_physical_size.value);
+ close(m_descriptor);
+ }
+
+ auto simulated_memory::clear() -> void
+ {
+ std::memset(m_physical_base, 0, m_physical_size.value);
+ }
+
+ auto simulated_memory::physical_base() noexcept -> std::byte *
+ {
+ return m_physical_base;
+ }
+
+ auto simulated_memory::physical_base() const noexcept -> std::byte const *
+ {
+ return m_physical_base;
+ }
+
+ auto simulated_memory::physical_size() const noexcept -> kstd::units::bytes
+ {
+ return m_physical_size;
+ }
+
+ auto simulated_memory::virtual_base() const noexcept -> kapi::memory::linear_address
+ {
+ return kapi::memory::linear_address{m_virtual_base};
+ }
+
+ auto simulated_memory::virtual_size() const noexcept -> kstd::units::bytes
+ {
+ return m_virtual_size;
+ }
+
+ auto simulated_memory::map(kstd::units::bytes size, std::byte * to, off_t offset) -> std::byte *
+ {
+ auto mapped_ptr = mmap(to, size.value, PROT_READ | PROT_WRITE, MAP_SHARED | MAP_FIXED, m_descriptor, offset);
+ if (mapped_ptr == MAP_FAILED)
+ {
+ auto error = std::format("Failed to map page: {}", strerror(errno));
+ throw std::runtime_error(error);
+ }
+
+ return static_cast<std::byte *>(mapped_ptr);
+ }
+
+} // namespace kernel::tests \ No newline at end of file
diff --git a/kernel/src/test_support/state_reset_listener.cpp b/kernel/src/test_support/state_reset_listener.cpp
new file mode 100644
index 0000000..6bb7537
--- /dev/null
+++ b/kernel/src/test_support/state_reset_listener.cpp
@@ -0,0 +1,48 @@
+#include <kernel/filesystem/open_file_table.hpp>
+#include <kernel/test_support/boot_modules.hpp>
+#include <kernel/test_support/cio.hpp>
+#include <kernel/test_support/cpu.hpp>
+#include <kernel/test_support/devices/storage/management.hpp>
+#include <kernel/test_support/filesystem/open_file_table.hpp>
+#include <kernel/test_support/filesystem/vfs.hpp>
+#include <kernel/test_support/memory.hpp>
+
+#include <kapi/cio.hpp>
+#include <kapi/cpu.hpp>
+#include <kapi/memory.hpp>
+
+#include <catch2/catch_test_case_info.hpp>
+#include <catch2/interfaces/catch_interfaces_reporter.hpp>
+#include <catch2/reporters/catch_reporter_event_listener.hpp>
+#include <catch2/reporters/catch_reporter_registrars.hpp>
+
+struct state_reset_listener : Catch::EventListenerBase
+{
+ using EventListenerBase::EventListenerBase;
+
+ void testCaseStarting(Catch::TestCaseInfo const &) override
+ {
+ kernel::filesystem::open_file_table::init();
+
+ kapi::cio::init();
+ kapi::cpu::init();
+ kapi::memory::init();
+ }
+
+ void testCaseEnded(Catch::TestCaseStats const &) override
+ {
+ kernel::tests::filesystem::open_file_table::deinit();
+ kernel::tests::filesystem::vfs::deinit();
+ kernel::tests::boot_modules::deinit();
+ kernel::tests::devices::storage::management::deinit();
+
+ kernel::tests::memory::deinit();
+ kernel::tests::cpu::deinit();
+ kernel::tests::cio::deinit();
+ }
+};
+
+#pragma GCC diagnostic push
+#pragma GCC diagnostic ignored "-Wpedantic"
+CATCH_REGISTER_LISTENER(state_reset_listener);
+#pragma GCC diagnostic pop \ No newline at end of file