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
54 * This structure provides the VFS with the functions required to read/write
55 * the file (or directory) that it represents.
57 typedef struct sVFS_Node {
60 * \brief Fields used by the driver to identify what data this node
64 Uint64 Inode; //!< Inode ID (Essentially another ImplInt)
65 Uint ImplInt; //!< Implementation Usable Integer
66 void *ImplPtr; //!< Implementation Usable Pointer
71 int ReferenceCount; //!< Number of times the node is used
73 Uint64 Size; //!< File Size
75 Uint32 Flags; //!< File Flags
81 Sint64 ATime; //!< Last Accessed Time
82 Sint64 MTime; //!< Last Modified Time
83 Sint64 CTime; //!< Creation Time
89 * \name Access controll
92 tUID UID; //!< ID of Owning User
93 tGID GID; //!< ID of Owning Group
95 int NumACLs; //!< Number of ACL entries
96 tVFS_ACL *ACLs; //!< Access Controll List pointer
102 * \name Common Functions
103 * \brief Functions that are used no matter the value of .Flags
107 * \brief Reference the node
108 * \param Node Pointer to this node
110 void (*Reference)(struct sVFS_Node *Node);
112 * \brief Close (dereference) the node
113 * \param Node Pointer to this node
115 * Usually .Close is used to write any changes to the node back to
116 * the persistent storage.
118 void (*Close)(struct sVFS_Node *Node);
121 * \brief Send an IO Control
122 * \param Node Pointer to this node
123 * \param Id IOCtl call number
124 * \param Data Pointer to data to pass to the driver
125 * \return Implementation defined
127 int (*IOCtl)(struct sVFS_Node *Node, int Id, void *Data);
134 * \name Buffer Functions
135 * \brief Functions for accessing a buffer-type file (normal file or
141 * \brief Read from the file
142 * \param Node Pointer to this node
143 * \param Offset Byte offset in the file
144 * \param Length Number of bytes to read
145 * \param Buffer Destination for read data
146 * \return Number of bytes read
148 Uint64 (*Read)(struct sVFS_Node *Node, Uint64 Offset, Uint64 Length, void *Buffer);
150 * \brief Write to the file
151 * \param Node Pointer to this node
152 * \param Offset Byte offser in the file
153 * \param Length Number of bytes to write
154 * \param Buffer Source of written data
155 * \return Number of bytes read
157 Uint64 (*Write)(struct sVFS_Node *Node, Uint64 Offset, Uint64 Length, void *Buffer);
164 * \name Directory Functions
168 * \brief Find an directory entry by name
169 * \param Node Pointer to this node
170 * \param Name Name of the file wanted
171 * \return Pointer to the requested node or NULL if it cannot be found
172 * \note The node returned must be accessable until ::tVFS_Node.Close
173 * is called and ReferenceCount reaches zero.
175 struct sVFS_Node *(*FindDir)(struct sVFS_Node *Node, char *Name);
178 * \brief Read from a directory
179 * \param Node Pointer to this node
180 * \param Pos Offset in the directory
181 * \return Pointer to the name of the item on the heap (will be freed
182 * by the caller). If the directory end has been reached, NULL
184 * If an item is required to be skipped either &::NULLNode,
185 * ::VFS_SKIP or ::VFS_SKIPN(0...1023) will be returned.
187 char *(*ReadDir)(struct sVFS_Node *Node, int Pos);
190 * \brief Create a node in a directory
191 * \param Node Pointer to this node
192 * \param Name Name of the new child
193 * \param Flags Flags to apply to the new child (directory or symlink)
194 * \return Boolean success
196 int (*MkNod)(struct sVFS_Node *Node, char *Name, Uint Flags);
199 * \brief Relink (Rename/Remove) a file/directory
200 * \param Node Pointer to this node
201 * \param OldName Name of the item to move/delete
202 * \param NewName New name (or NULL if unlinking is wanted)
203 * \return Boolean Success
205 int (*Relink)(struct sVFS_Node *Node, char *OldName, char *NewName);
213 * \brief VFS Driver (Filesystem) Definition
215 typedef struct sVFS_Driver
217 //! \brief Unique Identifier for this filesystem type
219 //! \brief Flags applying to this driver
222 //! \brief Callback to mount a device
223 tVFS_Node *(*InitDevice)(char *Device, char **Options);
224 //! \brief Callback to unmount a device
225 void (*Unmount)(tVFS_Node *Node);
226 //! \brief Used internally (next driver in the chain)
227 struct sVFS_Driver *Next;
231 //! \brief Maximum number of elements that can be skipped in one return
232 #define VFS_MAXSKIP ((void*)1024)
233 //! \brief Skip a single entry in readdir
234 #define VFS_SKIP ((void*)1)
235 //! \brief Skip \a n entries in readdir
236 #define VFS_SKIPN(n) ((void*)(n))
238 extern tVFS_Node NULLNode; //!< NULL VFS Node (Ignored/Skipped)
241 * \brief Simple ACLs to aid writing drivers
244 extern tVFS_ACL gVFS_ACL_EveryoneRWX; //!< Everyone Read/Write/Execute
245 extern tVFS_ACL gVFS_ACL_EveryoneRW; //!< Everyone Read/Write
246 extern tVFS_ACL gVFS_ACL_EveryoneRX; //!< Everyone Read/Execute
247 extern tVFS_ACL gVFS_ACL_EveryoneRO; //!< Everyone Read only
254 * \fn int VFS_AddDriver(tVFS_Driver *Info)
255 * \brief Registers the driver with the DevFS layer
256 * \param Info Driver information structure
258 extern int VFS_AddDriver(tVFS_Driver *Info);
260 * \fn tVFS_Driver *VFS_GetFSByName(char *Name)
261 * \brief Get the information structure of a driver given its name
262 * \param Name Name of filesystem driver to find
264 extern tVFS_Driver *VFS_GetFSByName(char *Name);
266 * \fn tVFS_ACL *VFS_UnixToAcessACL(Uint Mode, Uint Owner, Uint Group)
267 * \brief Transforms Unix Permssions into Acess ACLs
268 * \param Mode Unix RWXrwxRWX mask
269 * \param Owner UID of the file's owner
270 * \param Group GID of the file's owning group
271 * \return An array of 3 Acess ACLs
273 extern tVFS_ACL *VFS_UnixToAcessACL(Uint Mode, Uint Owner, Uint Group);
278 * \brief Functions to allow a node to be cached in memory by the VFS
280 * These functions store a node for the driver, to prevent it from having
281 * to re-generate the node on each call to FindDir. It also allows for
282 * fast cleanup when a filesystem is unmounted.
286 * \fn int Inode_GetHandle()
287 * \brief Gets a unique handle to the Node Cache
288 * \return A unique handle for use for the rest of the Inode_* functions
290 extern int Inode_GetHandle();
292 * \fn tVFS_Node *Inode_GetCache(int Handle, Uint64 Inode)
293 * \brief Gets an inode from the node cache
294 * \param Handle A handle returned by Inode_GetHandle()
295 * \param Inode Value of the Inode field of the ::tVFS_Node you want
296 * \return A pointer to the cached node
298 extern tVFS_Node *Inode_GetCache(int Handle, Uint64 Inode);
300 * \fn tVFS_Node *Inode_CacheNode(int Handle, tVFS_Node *Node)
301 * \brief Caches a node in the Node Cache
302 * \param Handle A handle returned by Inode_GetHandle()
303 * \param Node A pointer to the node to be cached (a copy is taken)
304 * \return A pointer to the node in the node cache
306 extern tVFS_Node *Inode_CacheNode(int Handle, tVFS_Node *Node);
308 * \fn void Inode_UncacheNode(int Handle, Uint64 Inode)
309 * \brief Dereferences (and removes if needed) a node from the cache
310 * \param Handle A handle returned by Inode_GetHandle()
311 * \param Inode Value of the Inode field of the ::tVFS_Node you want to remove
313 extern void Inode_UncacheNode(int Handle, Uint64 Inode);
315 * \fn void Inode_ClearCache(int Handle)
316 * \brief Clears the cache for a handle
317 * \param Handle A handle returned by Inode_GetHandle()
319 extern void Inode_ClearCache(int Handle);