X-Git-Url: https://git.ucc.asn.au/?a=blobdiff_plain;f=Kernel%2Finclude%2Fvfs.h;h=a7821048bc7be96e10b3bfe71e6018b7b5a10643;hb=48c3c3735e3445cb2f182a12be4b24507b4a995a;hp=7850600cf79c84eda2be8bfa44d2cd0c827847d7;hpb=04b368645c34cc3853fc13f93e33ac7878be8479;p=tpg%2Facess2.git diff --git a/Kernel/include/vfs.h b/Kernel/include/vfs.h index 7850600c..a7821048 100644 --- a/Kernel/include/vfs.h +++ b/Kernel/include/vfs.h @@ -5,103 +5,235 @@ /** * \file vfs.h * \brief Acess VFS Layer + * + * The Acess Virtual File System (VFS) provides abstraction of multiple + * physical filesystems, network storage and devices (both hardware and + * virtual) to the user. + * + * The core of the VFS is the concept of a \ref tVFS_Node "VFS Node". + * A VFS Node represents a "file" in the VFS tree, this can be any sort + * of file (an ordinary file, a directory, a symbolic link or a device) + * depending on the bits set in the \ref tVFS_Node.Flags Flags field. + * - For more information see "VFS Node Flags" */ #ifndef _VFS_H #define _VFS_H -#include +#include -//! \name ACL Permissions -//! \{ /** - * \brief Readable - */ -#define VFS_PERM_READ 0x00000001 -/** - * \brief Writeable - */ -#define VFS_PERM_WRITE 0x00000002 -/** - * \brief Append allowed + * \name tVFS_Node Flags + * \brief Flag values for tVFS_Node.Flags + * \{ */ -#define VFS_PERM_APPEND 0x00000004 +//! \todo Is this still needed +#define VFS_FFLAG_READONLY 0x01 //!< Readonly File /** - * \brief Executable + * \brief Directory Flag + * + * This flag marks the tVFS_Node as describing a directory, and says + * that the tVFS_Node.FindDir, tVFS_Node.ReadDir, tVFS_Node.MkNod and + * tVFS_Node.Relink function pointers are valid. + * For a directory the tVFS_Node.Size field contains the number of files + * within the directory, or -1 for undetermined. */ -#define VFS_PERM_EXECUTE 0x00000008 +#define VFS_FFLAG_DIRECTORY 0x02 /** - * \brief All permissions granted + * \brief Symbolic Link Flag + * + * Marks a file as a symbolic link */ -#define VFS_PERM_ALL 0x7FFFFFFF // Mask for permissions +#define VFS_FFLAG_SYMLINK 0x04 /** - * \brief Denies instead of granting permissions - * \note Denials take precedence + * \brief Set User ID Flag + * + * Allows an executable file to change it's executing user to the file's + * owner. + * In the case of a directory, it means that all immediate children will + * inherit the UID of the parent. */ -#define VFS_PERM_DENY 0x80000000 // Inverts permissions -//! \} - +#define VFS_FFLAG_SETUID 0x08 /** - * \name VFS Node Flags - * \{ + * \brief Set Group ID Flag + * + * Allows an executable file to change it's executing group to the file's + * owning group. + * In the case of a directory, it means that all immediate children will + * inherit the GID of the parent. */ -#define VFS_FFLAG_READONLY 0x01 //!< Read-only file -#define VFS_FFLAG_DIRECTORY 0x02 //!< Directory -#define VFS_FFLAG_SYMLINK 0x04 //!< Symbolic Link +#define VFS_FFLAG_SETGID 0x10 /** * \} */ /** * \brief VFS Node + * + * This structure provides the VFS with the functions required to read/write + * the file (or directory) that it represents. */ -typedef struct sVFS_Node { - Uint64 Inode; //!< Inode ID +typedef struct sVFS_Node +{ + /** + * \name Identifiers + * \brief Fields used by the driver to identify what data this node + * corresponds to. + * \{ + */ + Uint64 Inode; //!< Inode ID (Essentially another ImplInt) Uint ImplInt; //!< Implementation Usable Integer void *ImplPtr; //!< Implementation Usable Pointer + /** + * \} + */ + /** + * \name Node State + * \brief Stores the misc information about the node + * \{ + */ int ReferenceCount; //!< Number of times the node is used Uint64 Size; //!< File Size Uint32 Flags; //!< File Flags + /** + * \} + */ + /** + * \name Times + * \{ + */ Sint64 ATime; //!< Last Accessed Time Sint64 MTime; //!< Last Modified Time Sint64 CTime; //!< Creation Time + /** + * \} + */ - Uint UID; //!< Owning User - Uint GID; //!< Owning Group + /** + * \name Access controll + * \{ + */ + tUID UID; //!< ID of Owning User + tGID GID; //!< ID of Owning Group int NumACLs; //!< Number of ACL entries - tVFS_ACL *ACLs; //!< ACL Entries + tVFS_ACL *ACLs; //!< Access Controll List pointer + /** + * \} + */ - //! Reference the node + /** + * \name Common Functions + * \brief Functions that are used no matter the value of .Flags + * \{ + */ + /** + * \brief Reference the node + * \param Node Pointer to this node + */ void (*Reference)(struct sVFS_Node *Node); - //! Close (dereference) the node + /** + * \brief Close (dereference) the node + * \param Node Pointer to this node + * + * Usually .Close is used to write any changes to the node back to + * the persistent storage. + */ void (*Close)(struct sVFS_Node *Node); - //! Send an IO Control + + /** + * \brief Send an IO Control + * \param Node Pointer to this node + * \param Id IOCtl call number + * \param Data Pointer to data to pass to the driver + * \return Implementation defined + */ int (*IOCtl)(struct sVFS_Node *Node, int Id, void *Data); - //! \brief Read from the file + /** + * } + */ + + /** + * \name Buffer Functions + * \brief Functions for accessing a buffer-type file (normal file or + * symbolic link) + * \{ + */ + + /** + * \brief Read from the file + * \param Node Pointer to this node + * \param Offset Byte offset in the file + * \param Length Number of bytes to read + * \param Buffer Destination for read data + * \return Number of bytes read + */ Uint64 (*Read)(struct sVFS_Node *Node, Uint64 Offset, Uint64 Length, void *Buffer); - //! \brief Write to the file + /** + * \brief Write to the file + * \param Node Pointer to this node + * \param Offset Byte offser in the file + * \param Length Number of bytes to write + * \param Buffer Source of written data + * \return Number of bytes read + */ Uint64 (*Write)(struct sVFS_Node *Node, Uint64 Offset, Uint64 Length, void *Buffer); - //! \brief Find an directory entry by name - //! \note The node returned must be accessable until ::tVFS_Node.Close is called + /** + * } + */ + + /** + * \name Directory Functions + * \{ + */ + /** + * \brief Find an directory entry by name + * \param Node Pointer to this node + * \param Name Name of the file wanted + * \return Pointer to the requested node or NULL if it cannot be found + * \note The node returned must be accessable until ::tVFS_Node.Close + * is called and ReferenceCount reaches zero. + */ struct sVFS_Node *(*FindDir)(struct sVFS_Node *Node, char *Name); - //! \brief Read from a directory - //! \note MUST return a heap address + /** + * \brief Read from a directory + * \param Node Pointer to this node + * \param Pos Offset in the directory + * \return Pointer to the name of the item on the heap (will be freed + * by the caller). If the directory end has been reached, NULL + * will be returned. + * If an item is required to be skipped either &::NULLNode, + * ::VFS_SKIP or ::VFS_SKIPN(0...1023) will be returned. + */ char *(*ReadDir)(struct sVFS_Node *Node, int Pos); - //! \brief Create a node in a directory + /** + * \brief Create a node in a directory + * \param Node Pointer to this node + * \param Name Name of the new child + * \param Flags Flags to apply to the new child (directory or symlink) + * \return Boolean success + */ int (*MkNod)(struct sVFS_Node *Node, char *Name, Uint Flags); - //! \brief Relink (Rename/Remove) a file/directory + /** + * \brief Relink (Rename/Remove) a file/directory + * \param Node Pointer to this node + * \param OldName Name of the item to move/delete + * \param NewName New name (or NULL if unlinking is wanted) + * \return Zero on Success, non-zero on error (see errno.h) + */ int (*Relink)(struct sVFS_Node *Node, char *OldName, char *NewName); - - //!< \todo Complete + + /** + * } + */ } tVFS_Node; /** @@ -132,7 +264,8 @@ typedef struct sVFS_Driver extern tVFS_Node NULLNode; //!< NULL VFS Node (Ignored/Skipped) /** - * \name Simple ACLs to aid writing drivers + * \name Static ACLs + * \brief Simple ACLs to aid writing drivers * \{ */ extern tVFS_ACL gVFS_ACL_EveryoneRWX; //!< Everyone Read/Write/Execute @@ -167,8 +300,15 @@ extern tVFS_Driver *VFS_GetFSByName(char *Name); extern tVFS_ACL *VFS_UnixToAcessACL(Uint Mode, Uint Owner, Uint Group); // --- Node Cache -- -//! \name Node Cache -//! \{ +/** + * \name Node Cache + * \brief Functions to allow a node to be cached in memory by the VFS + * + * These functions store a node for the driver, to prevent it from having + * to re-generate the node on each call to FindDir. It also allows for + * fast cleanup when a filesystem is unmounted. + * \{ + */ /** * \fn int Inode_GetHandle() * \brief Gets a unique handle to the Node Cache @@ -192,7 +332,7 @@ extern tVFS_Node *Inode_GetCache(int Handle, Uint64 Inode); */ extern tVFS_Node *Inode_CacheNode(int Handle, tVFS_Node *Node); /** - * \fn void Inode_UncacheNode(int Handle, Uint64 Inode) + * \fn int Inode_UncacheNode(int Handle, Uint64 Inode) * \brief Dereferences (and removes if needed) a node from the cache * \param Handle A handle returned by Inode_GetHandle() * \param Inode Value of the Inode field of the ::tVFS_Node you want to remove @@ -205,6 +345,8 @@ extern void Inode_UncacheNode(int Handle, Uint64 Inode); */ extern void Inode_ClearCache(int Handle); -//! \} +/** + * \} + */ #endif