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Diffstat (limited to 'kernel/kernel/filesystem/vfs.hpp')
| -rw-r--r-- | kernel/kernel/filesystem/vfs.hpp | 113 |
1 files changed, 113 insertions, 0 deletions
diff --git a/kernel/kernel/filesystem/vfs.hpp b/kernel/kernel/filesystem/vfs.hpp new file mode 100644 index 00000000..ddc9a9bc --- /dev/null +++ b/kernel/kernel/filesystem/vfs.hpp @@ -0,0 +1,113 @@ +#ifndef TEACH_OS_KERNEL_FILESYSTEM_VFS_HPP +#define TEACH_OS_KERNEL_FILESYSTEM_VFS_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 <kstd/memory> + +#include <string_view> +#include <utility> + +namespace kernel::filesystem +{ + /** + @brief The virtual filesystem (VFS) is responsible for managing mounted filesystems and providing a unified interface + for file operations across different filesystem types. The VFS maintains a mount table to keep track of mounted + filesystems and their associated mount points. It provides methods for opening files by path, which involvesresolving + the path to the appropriate mounted filesystem and delegating the file operation to that filesystem's implementation. + */ + struct vfs + { + /** + @brief Results for VFS operations. + */ + enum class operation_result : int + { + success = 0, + invalid_path = -1, + non_existent_path = -2, + mount_point_not_found = -3, + unmount_failed = -4, + invalid_filesystem = -5 + }; + + vfs(); + + /** + @brief Initialize the virtual filesystem. + @warning Panics if the VFS has already been initialized. + */ + auto static init() -> void; + + /** + @brief Get the singleton instance of the virtual filesystem. + @return A reference to the VFS instance. + @warning Panics if the VFS has not been initialized yet. + */ + auto static get() -> vfs &; + + /** + @brief Destructor for the VFS. + */ + ~vfs() = default; + + /** + @brief Open a file by its @p path. This method resolves the path and returns the corresponding dentry. + @param path The path to the file to open. + @return A shared pointer to the dentry or a null pointer if the file could not be opened. + */ + auto open(std::string_view path) -> kstd::shared_ptr<dentry>; + + /** + @brief Close a file by its associated @p path. + @param path The path to the file to close. + @return The result of the close operation. + */ + auto close(std::string_view path) -> operation_result; + + /** + @brief Mount a @p source path to a specific @p target path. + @param source The source of the filesystem to mount. + @param target The path where the filesystem should be mounted. + @return The result of the mount operation. + */ + auto do_mount(std::string_view source, std::string_view target) -> operation_result; + + /** + @brief Unmount the filesystem mounted at the specified @p path. + @param path The path where the filesystem is mounted. + @return The result of the unmount operation. + */ + auto unmount(std::string_view path) -> operation_result; + + private: + /** + * Note: Resolving a dentry requires traversing mount points; since the + * associated 'mount' object is discovered as a byproduct of this + * traversal, we return it alongside the dentry to avoid redundant + * lookups in callers that require mount context. + * + * If only one component is needed, the convenience wrappers can be used: + * - resolve_path() for the dentry only. + * - find_mount() for the mount context only. + */ + [[nodiscard]] auto resolve_path_internal(std::string_view path) const + -> std::pair<kstd::shared_ptr<dentry>, kstd::shared_ptr<mount>>; + [[nodiscard]] auto resolve_path(std::string_view path) const -> kstd::shared_ptr<dentry>; + [[nodiscard]] auto find_mount(std::string_view path) const -> kstd::shared_ptr<mount>; + + auto 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 = nullptr) -> void; + + auto graft_persistent_device_fs(kstd::shared_ptr<devfs::filesystem> const & device_fs) -> void; + + mount_table m_mount_table{}; + }; +} // namespace kernel::filesystem + +#endif
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