7 * \brief Acess VFS Layer
9 * The Acess Virtual File System (VFS) provides abstraction of multiple
10 * physical filesystems, network storage and devices (both hardware and
11 * virtual) to the user.
13 * The core of the VFS is the concept of a \ref tVFS_Node "VFS Node".
14 * A VFS Node represents a "file" in the VFS tree, this can be any sort
15 * of file (an ordinary file, a directory, a symbolic link or a device)
16 * depending on the bits set in the \ref tVFS_Node.Flags Flags field.
17 * - For more information see "VFS Node Flags"
25 * \brief Thread list datatype for VFS_Select
27 typedef struct sVFS_SelectList tVFS_SelectList;
30 * \name tVFS_Node Flags
31 * \brief Flag values for tVFS_Node.Flags
34 //! \todo Is this still needed
35 #define VFS_FFLAG_READONLY 0x01 //!< Readonly File
37 * \brief Directory Flag
39 * This flag marks the tVFS_Node as describing a directory, and says
40 * that the tVFS_Node.FindDir, tVFS_Node.ReadDir, tVFS_Node.MkNod and
41 * tVFS_Node.Relink function pointers are valid.
42 * For a directory the tVFS_Node.Size field contains the number of files
43 * within the directory, or -1 for undetermined.
45 #define VFS_FFLAG_DIRECTORY 0x02
47 * \brief Symbolic Link Flag
49 * Marks a file as a symbolic link
51 #define VFS_FFLAG_SYMLINK 0x04
53 * \brief Set User ID Flag
55 * Allows an executable file to change it's executing user to the file's
57 * In the case of a directory, it means that all immediate children will
58 * inherit the UID of the parent.
60 #define VFS_FFLAG_SETUID 0x08
62 * \brief Set Group ID Flag
64 * Allows an executable file to change it's executing group to the file's
66 * In the case of a directory, it means that all immediate children will
67 * inherit the GID of the parent.
69 #define VFS_FFLAG_SETGID 0x10
75 * \brief Represents a node (file or directory) in the VFS tree
77 * This structure provides the VFS with the functions required to read/write
78 * the file (or directory) that it represents.
80 typedef struct sVFS_Node
84 * \brief Fields used by the driver to identify what data this node
88 Uint64 Inode; //!< Inode ID (Essentially another ImplInt)
89 Uint ImplInt; //!< Implementation Usable Integer
90 void *ImplPtr; //!< Implementation Usable Pointer
97 * \brief Stores the misc information about the node
100 int ReferenceCount; //!< Number of times the node is used
102 Uint64 Size; //!< File Size
104 Uint32 Flags; //!< File Flags
107 * \brief Pointer to cached data (FS Specific)
108 * \note The Inode_* functions will free when the node is uncached
115 * \note Provided for the Filesystem driver's use
127 Sint64 ATime; //!< Last Accessed Time
128 Sint64 MTime; //!< Last Modified Time
129 Sint64 CTime; //!< Creation Time
135 * \name Access control
138 tUID UID; //!< ID of Owning User
139 tGID GID; //!< ID of Owning Group
141 int NumACLs; //!< Number of ACL entries
142 tVFS_ACL *ACLs; //!< Access Controll List pointer
148 * \name VFS_Select() fields
152 tVFS_SelectList *ReadThreads; //!< Threads waiting to read
154 tVFS_SelectList *WriteThreads; //!< Threads waiting to write
156 tVFS_SelectList *ErrorThreads; //!< Threads waiting for an error
162 * \name Common Functions
163 * \brief Functions that are used no matter the value of .Flags
167 * \brief Reference the node
168 * \param Node Pointer to this node
170 void (*Reference)(struct sVFS_Node *Node);
172 * \brief Close (dereference) the node
173 * \param Node Pointer to this node
175 * Usually .Close is used to write any changes to the node back to
176 * the persistent storage.
178 void (*Close)(struct sVFS_Node *Node);
181 * \brief Send an IO Control
182 * \param Node Pointer to this node
183 * \param Id IOCtl call number
184 * \param Data Pointer to data to pass to the driver
185 * \return Implementation defined
187 int (*IOCtl)(struct sVFS_Node *Node, int Id, void *Data);
194 * \name Buffer Functions
195 * \brief Functions for accessing a buffer-type file (normal file or
201 * \brief Read from the file
202 * \param Node Pointer to this node
203 * \param Offset Byte offset in the file
204 * \param Length Number of bytes to read
205 * \param Buffer Destination for read data
206 * \return Number of bytes read
208 Uint64 (*Read)(struct sVFS_Node *Node, Uint64 Offset, Uint64 Length, void *Buffer);
210 * \brief Write to the file
211 * \param Node Pointer to this node
212 * \param Offset Byte offser in the file
213 * \param Length Number of bytes to write
214 * \param Buffer Source of written data
215 * \return Number of bytes read
217 Uint64 (*Write)(struct sVFS_Node *Node, Uint64 Offset, Uint64 Length, void *Buffer);
224 * \name Directory Functions
228 * \brief Find an directory entry by name
229 * \param Node Pointer to this node
230 * \param Name Name of the file wanted
231 * \return Pointer to the requested node or NULL if it cannot be found
232 * \note The node returned must be accessable until ::tVFS_Node.Close
233 * is called and ReferenceCount reaches zero.
235 struct sVFS_Node *(*FindDir)(struct sVFS_Node *Node, const char *Name);
238 * \brief Read from a directory
239 * \param Node Pointer to this node
240 * \param Pos Offset in the directory
241 * \return Pointer to the name of the item on the heap (will be freed
242 * by the caller). If the directory end has been reached, NULL
244 * If an item is required to be skipped either &::NULLNode,
245 * ::VFS_SKIP or ::VFS_SKIPN(0...1023) will be returned.
247 char *(*ReadDir)(struct sVFS_Node *Node, int Pos);
250 * \brief Create a node in a directory
251 * \param Node Pointer to this node
252 * \param Name Name of the new child
253 * \param Flags Flags to apply to the new child (directory or symlink)
254 * \return Zero on Success, non-zero on error (see errno.h)
256 int (*MkNod)(struct sVFS_Node *Node, const char *Name, Uint Flags);
259 * \brief Relink (Rename/Remove) a file/directory
260 * \param Node Pointer to this node
261 * \param OldName Name of the item to move/delete
262 * \param NewName New name (or NULL if unlinking is wanted)
263 * \return Zero on Success, non-zero on error (see errno.h)
265 int (*Relink)(struct sVFS_Node *Node, const char *OldName, const char *NewName);
268 * \brief Link a node to a name
269 * \param Node Pointer to this node (directory)
270 * \param Child Node to create a new link to
271 * \param NewName Name for the new link
272 * \return Zeron on success, non-zero on error (see errno.h)
274 int (*Link)(struct sVFS_Node *Node, struct sVFS_Node *Child, const char *NewName);
282 * \brief VFS Driver (Filesystem) Definition
284 typedef struct sVFS_Driver
286 //! \brief Unique Identifier for this filesystem type
288 //! \brief Flags applying to this driver
291 //! \brief Callback to mount a device
292 tVFS_Node *(*InitDevice)(const char *Device, const char **Options);
293 //! \brief Callback to unmount a device
294 void (*Unmount)(tVFS_Node *Node);
295 //! \brief Used internally (next driver in the chain)
296 struct sVFS_Driver *Next;
300 //! \brief Maximum number of elements that can be skipped in one return
301 #define VFS_MAXSKIP ((void*)1024)
302 //! \brief Skip a single entry in readdir
303 #define VFS_SKIP ((void*)1)
304 //! \brief Skip \a n entries in readdir
305 #define VFS_SKIPN(n) ((void*)(n))
307 extern tVFS_Node NULLNode; //!< NULL VFS Node (Ignored/Skipped)
310 * \brief Simple ACLs to aid writing drivers
313 extern tVFS_ACL gVFS_ACL_EveryoneRWX; //!< Everyone Read/Write/Execute
314 extern tVFS_ACL gVFS_ACL_EveryoneRW; //!< Everyone Read/Write
315 extern tVFS_ACL gVFS_ACL_EveryoneRX; //!< Everyone Read/Execute
316 extern tVFS_ACL gVFS_ACL_EveryoneRO; //!< Everyone Read only
323 * \fn int VFS_AddDriver(tVFS_Driver *Info)
324 * \brief Registers the driver with the DevFS layer
325 * \param Info Driver information structure
327 extern int VFS_AddDriver(tVFS_Driver *Info);
329 * \fn tVFS_Driver *VFS_GetFSByName(char *Name)
330 * \brief Get the information structure of a driver given its name
331 * \param Name Name of filesystem driver to find
333 extern tVFS_Driver *VFS_GetFSByName(const char *Name);
335 * \fn tVFS_ACL *VFS_UnixToAcessACL(Uint Mode, Uint Owner, Uint Group)
336 * \brief Transforms Unix Permssions into Acess ACLs
337 * \param Mode Unix RWXrwxRWX mask
338 * \param Owner UID of the file's owner
339 * \param Group GID of the file's owning group
340 * \return An array of 3 Acess ACLs
342 extern tVFS_ACL *VFS_UnixToAcessACL(Uint Mode, Uint Owner, Uint Group);
346 enum eVFS_SelectTypes
354 * \brief Wait for an event on a node
355 * \param Node Node to wait on
356 * \param Type Type of wait
357 * \param Timeout Time to wait (NULL for infinite wait)
358 * \return Number of nodes that actioned (0 or 1)
360 extern int VFS_SelectNode(tVFS_Node *Node, enum eVFS_SelectTypes Type, tTime *Timeout);
362 extern int VFS_MarkFull(tVFS_Node *Node, BOOL IsBufferFull);
363 extern int VFS_MarkAvaliable(tVFS_Node *Node, BOOL IsDataAvaliable);
364 extern int VFS_MarkError(tVFS_Node *Node, BOOL IsErrorState);
369 * \brief Functions to allow a node to be cached in memory by the VFS
371 * These functions store a node for the driver, to prevent it from having
372 * to re-generate the node on each call to FindDir. It also allows for
373 * fast cleanup when a filesystem is unmounted.
377 * \fn int Inode_GetHandle(void)
378 * \brief Gets a unique handle to the Node Cache
379 * \return A unique handle for use for the rest of the Inode_* functions
381 extern int Inode_GetHandle(void);
383 * \fn tVFS_Node *Inode_GetCache(int Handle, Uint64 Inode)
384 * \brief Gets an inode from the node cache
385 * \param Handle A handle returned by Inode_GetHandle()
386 * \param Inode Value of the Inode field of the ::tVFS_Node you want
387 * \return A pointer to the cached node
389 extern tVFS_Node *Inode_GetCache(int Handle, Uint64 Inode);
391 * \fn tVFS_Node *Inode_CacheNode(int Handle, tVFS_Node *Node)
392 * \brief Caches a node in the Node Cache
393 * \param Handle A handle returned by Inode_GetHandle()
394 * \param Node A pointer to the node to be cached (a copy is taken)
395 * \return A pointer to the node in the node cache
397 extern tVFS_Node *Inode_CacheNode(int Handle, tVFS_Node *Node);
399 * \fn int Inode_UncacheNode(int Handle, Uint64 Inode)
400 * \brief Dereferences (and removes if needed) a node from the cache
401 * \param Handle A handle returned by Inode_GetHandle()
402 * \param Inode Value of the Inode field of the ::tVFS_Node you want to remove
404 extern void Inode_UncacheNode(int Handle, Uint64 Inode);
406 * \fn void Inode_ClearCache(int Handle)
407 * \brief Clears the cache for a handle
408 * \param Handle A handle returned by Inode_GetHandle()
410 extern void Inode_ClearCache(int Handle);