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 * \name tVFS_Node Flags
26 * \brief Flag values for tVFS_Node.Flags
29 //! \todo Is this still needed
30 #define VFS_FFLAG_READONLY 0x01 //!< Readonly File
32 * \brief Directory Flag
34 * This flag marks the tVFS_Node as describing a directory, and says
35 * that the tVFS_Node.FindDir, tVFS_Node.ReadDir, tVFS_Node.MkNod and
36 * tVFS_Node.Relink function pointers are valid.
37 * For a directory the tVFS_Node.Size field contains the number of files
38 * within the directory, or -1 for undetermined.
40 #define VFS_FFLAG_DIRECTORY 0x02
42 * \brief Symbolic Link Flag
44 * Marks a file as a symbolic link
46 #define VFS_FFLAG_SYMLINK 0x04
48 * \brief Set User ID Flag
50 * Allows an executable file to change it's executing user to the file's
52 * In the case of a directory, it means that all immediate children will
53 * inherit the UID of the parent.
55 #define VFS_FFLAG_SETUID 0x08
57 * \brief Set Group ID Flag
59 * Allows an executable file to change it's executing group to the file's
61 * In the case of a directory, it means that all immediate children will
62 * inherit the GID of the parent.
64 #define VFS_FFLAG_SETGID 0x10
72 * This structure provides the VFS with the functions required to read/write
73 * the file (or directory) that it represents.
75 typedef struct sVFS_Node
79 * \brief Fields used by the driver to identify what data this node
83 Uint64 Inode; //!< Inode ID (Essentially another ImplInt)
84 Uint ImplInt; //!< Implementation Usable Integer
85 void *ImplPtr; //!< Implementation Usable Pointer
90 int ReferenceCount; //!< Number of times the node is used
92 Uint64 Size; //!< File Size
94 Uint32 Flags; //!< File Flags
100 Sint64 ATime; //!< Last Accessed Time
101 Sint64 MTime; //!< Last Modified Time
102 Sint64 CTime; //!< Creation Time
108 * \name Access controll
111 tUID UID; //!< ID of Owning User
112 tGID GID; //!< ID of Owning Group
114 int NumACLs; //!< Number of ACL entries
115 tVFS_ACL *ACLs; //!< Access Controll List pointer
121 * \name Common Functions
122 * \brief Functions that are used no matter the value of .Flags
126 * \brief Reference the node
127 * \param Node Pointer to this node
129 void (*Reference)(struct sVFS_Node *Node);
131 * \brief Close (dereference) the node
132 * \param Node Pointer to this node
134 * Usually .Close is used to write any changes to the node back to
135 * the persistent storage.
137 void (*Close)(struct sVFS_Node *Node);
140 * \brief Send an IO Control
141 * \param Node Pointer to this node
142 * \param Id IOCtl call number
143 * \param Data Pointer to data to pass to the driver
144 * \return Implementation defined
146 int (*IOCtl)(struct sVFS_Node *Node, int Id, void *Data);
153 * \name Buffer Functions
154 * \brief Functions for accessing a buffer-type file (normal file or
160 * \brief Read from the file
161 * \param Node Pointer to this node
162 * \param Offset Byte offset in the file
163 * \param Length Number of bytes to read
164 * \param Buffer Destination for read data
165 * \return Number of bytes read
167 Uint64 (*Read)(struct sVFS_Node *Node, Uint64 Offset, Uint64 Length, void *Buffer);
169 * \brief Write to the file
170 * \param Node Pointer to this node
171 * \param Offset Byte offser in the file
172 * \param Length Number of bytes to write
173 * \param Buffer Source of written data
174 * \return Number of bytes read
176 Uint64 (*Write)(struct sVFS_Node *Node, Uint64 Offset, Uint64 Length, void *Buffer);
183 * \name Directory Functions
187 * \brief Find an directory entry by name
188 * \param Node Pointer to this node
189 * \param Name Name of the file wanted
190 * \return Pointer to the requested node or NULL if it cannot be found
191 * \note The node returned must be accessable until ::tVFS_Node.Close
192 * is called and ReferenceCount reaches zero.
194 struct sVFS_Node *(*FindDir)(struct sVFS_Node *Node, char *Name);
197 * \brief Read from a directory
198 * \param Node Pointer to this node
199 * \param Pos Offset in the directory
200 * \return Pointer to the name of the item on the heap (will be freed
201 * by the caller). If the directory end has been reached, NULL
203 * If an item is required to be skipped either &::NULLNode,
204 * ::VFS_SKIP or ::VFS_SKIPN(0...1023) will be returned.
206 char *(*ReadDir)(struct sVFS_Node *Node, int Pos);
209 * \brief Create a node in a directory
210 * \param Node Pointer to this node
211 * \param Name Name of the new child
212 * \param Flags Flags to apply to the new child (directory or symlink)
213 * \return Boolean success
215 int (*MkNod)(struct sVFS_Node *Node, char *Name, Uint Flags);
218 * \brief Relink (Rename/Remove) a file/directory
219 * \param Node Pointer to this node
220 * \param OldName Name of the item to move/delete
221 * \param NewName New name (or NULL if unlinking is wanted)
222 * \return Boolean Success
224 int (*Relink)(struct sVFS_Node *Node, char *OldName, char *NewName);
232 * \brief VFS Driver (Filesystem) Definition
234 typedef struct sVFS_Driver
236 //! \brief Unique Identifier for this filesystem type
238 //! \brief Flags applying to this driver
241 //! \brief Callback to mount a device
242 tVFS_Node *(*InitDevice)(char *Device, char **Options);
243 //! \brief Callback to unmount a device
244 void (*Unmount)(tVFS_Node *Node);
245 //! \brief Used internally (next driver in the chain)
246 struct sVFS_Driver *Next;
250 //! \brief Maximum number of elements that can be skipped in one return
251 #define VFS_MAXSKIP ((void*)1024)
252 //! \brief Skip a single entry in readdir
253 #define VFS_SKIP ((void*)1)
254 //! \brief Skip \a n entries in readdir
255 #define VFS_SKIPN(n) ((void*)(n))
257 extern tVFS_Node NULLNode; //!< NULL VFS Node (Ignored/Skipped)
260 * \brief Simple ACLs to aid writing drivers
263 extern tVFS_ACL gVFS_ACL_EveryoneRWX; //!< Everyone Read/Write/Execute
264 extern tVFS_ACL gVFS_ACL_EveryoneRW; //!< Everyone Read/Write
265 extern tVFS_ACL gVFS_ACL_EveryoneRX; //!< Everyone Read/Execute
266 extern tVFS_ACL gVFS_ACL_EveryoneRO; //!< Everyone Read only
273 * \fn int VFS_AddDriver(tVFS_Driver *Info)
274 * \brief Registers the driver with the DevFS layer
275 * \param Info Driver information structure
277 extern int VFS_AddDriver(tVFS_Driver *Info);
279 * \fn tVFS_Driver *VFS_GetFSByName(char *Name)
280 * \brief Get the information structure of a driver given its name
281 * \param Name Name of filesystem driver to find
283 extern tVFS_Driver *VFS_GetFSByName(char *Name);
285 * \fn tVFS_ACL *VFS_UnixToAcessACL(Uint Mode, Uint Owner, Uint Group)
286 * \brief Transforms Unix Permssions into Acess ACLs
287 * \param Mode Unix RWXrwxRWX mask
288 * \param Owner UID of the file's owner
289 * \param Group GID of the file's owning group
290 * \return An array of 3 Acess ACLs
292 extern tVFS_ACL *VFS_UnixToAcessACL(Uint Mode, Uint Owner, Uint Group);
297 * \brief Functions to allow a node to be cached in memory by the VFS
299 * These functions store a node for the driver, to prevent it from having
300 * to re-generate the node on each call to FindDir. It also allows for
301 * fast cleanup when a filesystem is unmounted.
305 * \fn int Inode_GetHandle()
306 * \brief Gets a unique handle to the Node Cache
307 * \return A unique handle for use for the rest of the Inode_* functions
309 extern int Inode_GetHandle();
311 * \fn tVFS_Node *Inode_GetCache(int Handle, Uint64 Inode)
312 * \brief Gets an inode from the node cache
313 * \param Handle A handle returned by Inode_GetHandle()
314 * \param Inode Value of the Inode field of the ::tVFS_Node you want
315 * \return A pointer to the cached node
317 extern tVFS_Node *Inode_GetCache(int Handle, Uint64 Inode);
319 * \fn tVFS_Node *Inode_CacheNode(int Handle, tVFS_Node *Node)
320 * \brief Caches a node in the Node Cache
321 * \param Handle A handle returned by Inode_GetHandle()
322 * \param Node A pointer to the node to be cached (a copy is taken)
323 * \return A pointer to the node in the node cache
325 extern tVFS_Node *Inode_CacheNode(int Handle, tVFS_Node *Node);
327 * \fn int Inode_UncacheNode(int Handle, Uint64 Inode)
328 * \brief Dereferences (and removes if needed) a node from the cache
329 * \param Handle A handle returned by Inode_GetHandle()
330 * \param Inode Value of the Inode field of the ::tVFS_Node you want to remove
332 extern void Inode_UncacheNode(int Handle, Uint64 Inode);
334 * \fn void Inode_ClearCache(int Handle)
335 * \brief Clears the cache for a handle
336 * \param Handle A handle returned by Inode_GetHandle()
338 extern void Inode_ClearCache(int Handle);