From 1db4c39c28c58c01ae13e15be4849c1fc9e9efff Mon Sep 17 00:00:00 2001
From: Marcel Braun <marcel.braun@ost.ch>
Date: Sun, 7 Jun 2026 18:47:00 +0200
Subject: Save wip of create_inode

---
 kernel/kernel/filesystem/ext2/filesystem.cpp | 87 ++++++++++++++++++++++++++++
 kernel/kernel/filesystem/ext2/filesystem.hpp | 19 ++++--
 2 files changed, 100 insertions(+), 6 deletions(-)

(limited to 'kernel')

diff --git a/kernel/kernel/filesystem/ext2/filesystem.cpp b/kernel/kernel/filesystem/ext2/filesystem.cpp
index 8860f213..7b0bce0e 100644
--- a/kernel/kernel/filesystem/ext2/filesystem.cpp
+++ b/kernel/kernel/filesystem/ext2/filesystem.cpp
@@ -153,6 +153,93 @@ namespace kernel::filesystem::ext2
     return kstd::failure(vfs_errc::no_such_file_or_directory);
   }
 
+  auto filesystem::create_inode(kstd::shared_ptr<kernel::filesystem::inode> const & parent, std::string_view name)
+      -> kstd::result<kstd::shared_ptr<kernel::filesystem::inode>>
+  {
+    if (!parent)
+    {
+      return kstd::failure(vfs_errc::invalid_inode);
+    }
+
+    if (!parent->is_directory())
+    {
+      return kstd::failure(vfs_errc::not_a_directory);
+    }
+
+    auto maybe_inode_number = allocate_inode();
+    if (!maybe_inode_number)
+    {
+      return kstd::failure(maybe_inode_number.error());
+    }
+
+    auto inode_number = maybe_inode_number.value();
+
+    inode_data new_inode_data{};
+
+    // TODO set mode depending on type/mode
+    new_inode_data.mode = 0x8000;
+    new_inode_data.size = 0;
+    new_inode_data.dir_acl = 0;
+    new_inode_data.links_count = 1;
+    new_inode_data.blocks = 0;
+    new_inode_data.block.fill(0);
+
+    if (auto write_result = write_inode(inode_number, new_inode_data); !write_result)
+    {
+      return kstd::failure(write_result.error());
+    }
+
+    // add directory entry to parent
+    if (auto * ext2_parent = static_cast<inode *>(parent.get()))
+    {
+      if (auto result = add_directory_entry(ext2_parent, name, inode_number, new_inode_data.mode);
+          !result)  // TODO handle mode correctly
+      {
+        return kstd::failure(result.error());
+      }
+      // TODO
+    }
+  }
+
+  auto filesystem::add_directory_entry(inode * ext2_parent, std::string_view name, uint32_t inode_number, uint16_t mode)
+      -> kstd::result<void>
+  {
+    auto block_count = inode_block_count(ext2_parent->data());
+    auto const last_block_index = block_count - 1;
+    auto const global_block_number =
+        map_inode_block_index_to_global_block_number(last_block_index, ext2_parent->data());
+
+    if (!global_block_number)
+    {
+      return kstd::failure(global_block_number.error());
+    }
+
+    kstd::vector<uint8_t> buffer(block_size());
+    if (auto read_result = read_block(*global_block_number, buffer.data()); !read_result)
+    {
+      return kstd::failure(read_result.error());
+    }
+
+    auto offset = 0uz;
+    while (true)
+    {
+      auto const * entry = reinterpret_cast<linked_directory_entry const *>(buffer.data() + offset);
+
+      if (offset + entry->rec_len >= block_size())
+      {
+        break;
+      }
+
+      offset += entry->rec_len;
+    }
+
+    auto const * last_entry = reinterpret_cast<linked_directory_entry const *>(buffer.data() + offset);
+
+    auto const last_entry_actual_length = 0;  // TODO
+
+    return kstd::success();
+  }
+
   auto filesystem::read_inode(uint32_t inode_number) const -> kstd::result<kstd::shared_ptr<inode>>
   {
     if (auto inode_offset = calculate_inode_offset(inode_number))
diff --git a/kernel/kernel/filesystem/ext2/filesystem.hpp b/kernel/kernel/filesystem/ext2/filesystem.hpp
index 33b7b95c..eaa42d01 100644
--- a/kernel/kernel/filesystem/ext2/filesystem.hpp
+++ b/kernel/kernel/filesystem/ext2/filesystem.hpp
@@ -67,6 +67,15 @@ namespace kernel::filesystem::ext2
     [[nodiscard]] auto lookup(kstd::shared_ptr<kernel::filesystem::inode> const & parent, std::string_view name) const
         -> kstd::result<kstd::shared_ptr<kernel::filesystem::inode>> override;
 
+    /**
+    @brief Creates a new inode with @p name within a @p parent directory.
+    @param parent The parent directory inode.
+    @param name The name of the inode to create.
+    @return A pointer to the created inode, or a null pointer if creation failed.
+    */
+    [[nodiscard]] auto create_inode(kstd::shared_ptr<kernel::filesystem::inode> const & parent, std::string_view name)
+        -> kstd::result<kstd::shared_ptr<kernel::filesystem::inode>>;  // TODO move into base class and override
+
     /**
     @brief Gets the size of a block in the filesystem.
     @return The size of a block in bytes.
@@ -102,12 +111,6 @@ namespace kernel::filesystem::ext2
     */
     auto allocate_blocks(size_t count) -> kstd::result<kstd::vector<uint32_t>>;
 
-    /**
-    @brief Allocates a new inode.
-    @return The inode number within the filesystem.
-    */
-    auto allocate_inode() -> kstd::result<uint32_t>;
-
     /**
     @brief Gets the size of an inode in the filesystem.
     @return The size of an inode in bytes.
@@ -162,6 +165,10 @@ namespace kernel::filesystem::ext2
 
     [[nodiscard]] auto indirect_levels() const -> std::array<indirect_level, 3>;
 
+    auto allocate_inode() -> kstd::result<uint32_t>;
+    auto add_directory_entry(inode * ext2_parent, std::string_view name, uint32_t inode_number, uint16_t mode)
+        -> kstd::result<void>;
+
     [[nodiscard]] auto calculate_inode_offset(uint32_t inode_number) const -> kstd::result<size_t>;
     [[nodiscard]] auto read_inode(uint32_t inode_number) const -> kstd::result<kstd::shared_ptr<inode>>;
     [[nodiscard]] auto read_block_number_at_index(uint32_t block_number, size_t index) const -> kstd::result<uint32_t>;
-- 
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