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#include "kernel/filesystem/vfs.hpp"
#include "kapi/system.hpp"
#include "kernel/devices/storage/storage_management.hpp"
#include "kernel/filesystem/dentry.hpp"
#include "kernel/filesystem/devfs/devfs_filesystem.hpp"
#include "kernel/filesystem/ext2/ext2_filesystem.hpp"
#include "kernel/filesystem/filesystem.hpp"
#include "kernel/filesystem/mount.hpp"
#include "kernel/filesystem/open_file_description.hpp"
#include "kernel/filesystem/rootfs/rootfs_filesystem.hpp"
#include <kstd/memory>
#include <optional>
#include <ranges>
#include <string_view>
namespace filesystem
{
namespace
{
constinit auto static active_vfs = std::optional<vfs>{};
} // namespace
auto vfs::init() -> void
{
if (active_vfs)
{
kapi::system::panic("[FILESYSTEM] vfs has already been initialized.");
}
active_vfs.emplace(vfs{});
active_vfs->init_internal();
}
auto vfs::init_internal() -> void
{
auto virtual_fs = kstd::make_shared<rootfs::rootfs_filesystem>();
virtual_fs->mount(nullptr);
auto virtual_root_dentry = kstd::make_shared<dentry>(nullptr, virtual_fs->root_inode(), "/");
m_mount_table.add_mount(kstd::make_shared<mount>(nullptr, virtual_root_dentry, virtual_fs));
auto storage_mgmt = devices::storage::storage_management::get();
if (auto boot_device = storage_mgmt.determine_boot_device())
{
// TODO BA-FS26 detect fs type from boot device and load corresponding fs, for now just assume ext2
auto boot_root_fs = kstd::make_shared<ext2::ext2_filesystem>();
boot_root_fs->mount(boot_device);
if (do_mount("/", boot_root_fs) != 0)
{
kapi::system::panic("[FILESYSTEM] failed to mount root filesystem.");
}
auto device_fs = kstd::make_shared<devfs::devfs_filesystem>();
device_fs->mount(nullptr);
if (do_mount("/dev", device_fs) != 0)
{
kapi::system::panic("[FILESYSTEM] failed to mount devfs at /dev.");
}
}
else
{
// TODO BA-FS26 ?? what when no boot_device == no modules loaded??
}
}
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<open_file_description>
{
if (auto dentry = resolve_path(path))
{
return kstd::make_shared<open_file_description>(dentry->get_inode());
}
return nullptr;
}
auto vfs::do_mount(std::string_view path, kstd::shared_ptr<filesystem> const & filesystem) -> int
{
if (!filesystem)
{
return -1; // TODO BA-FS26 panic or errorcode?
}
if (path.empty() || path.front() != '/')
{
return -1; // TODO BA-FS26 panic or errorcode?
}
// TODO BA-FS26 better path validation
if ((path.size() > 1 && path.back() == '/'))
{
return -1; // TODO BA-FS26 panic or errorcode?
}
if (auto mount_dentry = resolve_path(path))
{
// TODO BA-FS26 check if mount point is already mounted and handle it (unmount old fs, fail, etc.)
auto new_fs_root = kstd::make_shared<dentry>(mount_dentry, filesystem->root_inode());
auto new_mount = kstd::make_shared<mount>(mount_dentry, new_fs_root, filesystem);
m_mount_table.add_mount(new_mount);
mount_dentry->set_flag(dentry::dentry_flags::dcache_mounted);
return 0;
}
return -1;
}
auto vfs::resolve_path(std::string_view path) -> kstd::shared_ptr<dentry>
{
// TODO BA-FS26 implement full path resolution semantics.
// TODO BA-FS26 better path validation
// TODO BA-FS26 implement a path parser (maybe in libs?) and use it here and in do_mount
if (!path.empty() && path.front() == '/')
{
auto root_mount = m_mount_table.get_root_mount();
if (!root_mount)
{
kapi::system::panic("[FILESYSTEM] no root mount found.");
}
auto current_dentry = root_mount->root_dentry();
auto current_fs = root_mount->get_filesystem();
// TODO BA-FS26 use while to allow stacked mounts?
if (current_dentry->has_flag(dentry::dentry_flags::dcache_mounted))
{
auto mnt = m_mount_table.find_mount_by_dentry(current_dentry);
if (!mnt)
kapi::system::panic("[FILESYSTEM] dcache_mounted set but no covering mount found.");
current_dentry = mnt->root_dentry();
current_fs = mnt->get_filesystem();
}
auto path_parts =
std::views::split(path, '/') | std::views::filter([](auto const & part) { return !part.empty(); });
for (auto const & part : path_parts)
{
std::string_view part_view{part};
auto next_dentry = current_dentry->find_child(part_view);
if (!next_dentry)
{
if (auto found_inode = current_fs->lookup(current_dentry->get_inode(), part_view))
{
next_dentry = kstd::make_shared<dentry>(current_dentry, found_inode, part_view);
current_dentry->add_child(next_dentry);
}
else
{
return nullptr;
}
}
// TODO BA-FS26 use while to allow stacked mounts?
if (next_dentry->has_flag(dentry::dentry_flags::dcache_mounted))
{
auto found_mount = m_mount_table.find_mount_by_dentry(next_dentry);
current_fs = found_mount->get_filesystem();
current_dentry = found_mount->root_dentry();
}
else
{
current_dentry = next_dentry;
}
}
return current_dentry;
}
return nullptr;
}
} // namespace filesystem
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