xref: /haiku/headers/private/userlandfs/fuse/fuse.h (revision 820dca4df6c7bf955c46e8f6521b9408f50b2900)
1 /*
2   FUSE: Filesystem in Userspace
3   Copyright (C) 2001-2007  Miklos Szeredi <miklos@szeredi.hu>
4 
5   This program can be distributed under the terms of the GNU LGPLv2.
6   See the file COPYING.LIB.
7 */
8 
9 #ifndef _FUSE_H_
10 #define _FUSE_H_
11 
12 /** @file
13  *
14  * This file defines the library interface of FUSE
15  *
16  * IMPORTANT: you should define FUSE_USE_VERSION before including this
17  * header.  To use the newest API define it to 26 (recommended for any
18  * new application), to use the old API define it to 21 (default) 22
19  * or 25, to use the even older 1.X API define it to 11.
20  */
21 
22 #ifndef FUSE_USE_VERSION
23 #define FUSE_USE_VERSION 21
24 #endif
25 
26 #include "fuse_common.h"
27 
28 #include <fcntl.h>
29 #include <time.h>
30 #include <utime.h>
31 #include <sys/types.h>
32 #include <sys/stat.h>
33 #include <sys/statvfs.h>
34 
35 #ifdef __cplusplus
36 extern "C" {
37 #endif
38 
39 /* ----------------------------------------------------------- *
40  * Basic FUSE API					       *
41  * ----------------------------------------------------------- */
42 
43 /** Handle for a FUSE filesystem */
44 struct fuse;
45 
46 /** Structure containing a raw command */
47 struct fuse_cmd;
48 
49 /** Function to add an entry in a readdir() operation
50  *
51  * @param buf the buffer passed to the readdir() operation
52  * @param name the file name of the directory entry
53  * @param stat file attributes, can be NULL
54  * @param off offset of the next entry or zero
55  * @return 1 if buffer is full, zero otherwise
56  */
57 typedef int (*fuse_fill_dir_t) (void *buf, const char *name,
58 				const struct stat *stbuf, off_t off);
59 
60 /* Used by deprecated getdir() method */
61 typedef struct fuse_dirhandle *fuse_dirh_t;
62 typedef int (*fuse_dirfil_t) (fuse_dirh_t h, const char *name, int type,
63 			      ino_t ino);
64 
65 /**
66  * The file system operations:
67  *
68  * Most of these should work very similarly to the well known UNIX
69  * file system operations.  A major exception is that instead of
70  * returning an error in 'errno', the operation should return the
71  * negated error value (-errno) directly.
72  *
73  * All methods are optional, but some are essential for a useful
74  * filesystem (e.g. getattr).  Open, flush, release, fsync, opendir,
75  * releasedir, fsyncdir, access, create, ftruncate, fgetattr, lock,
76  * init and destroy are special purpose methods, without which a full
77  * featured filesystem can still be implemented.
78  */
79 struct fuse_operations {
80 	/** Get file attributes.
81 	 *
82 	 * Similar to stat().  The 'st_dev' and 'st_blksize' fields are
83 	 * ignored.	 The 'st_ino' field is ignored except if the 'use_ino'
84 	 * mount option is given.
85 	 */
86 	int (*getattr) (const char *, struct stat *);
87 
88 	/** Read the target of a symbolic link
89 	 *
90 	 * The buffer should be filled with a null terminated string.  The
91 	 * buffer size argument includes the space for the terminating
92 	 * null character.	If the linkname is too long to fit in the
93 	 * buffer, it should be truncated.	The return value should be 0
94 	 * for success.
95 	 */
96 	int (*readlink) (const char *, char *, size_t);
97 
98 	/* Deprecated, use readdir() instead */
99 	int (*getdir) (const char *, fuse_dirh_t, fuse_dirfil_t);
100 
101 	/** Create a file node
102 	 *
103 	 * This is called for creation of all non-directory, non-symlink
104 	 * nodes.  If the filesystem defines a create() method, then for
105 	 * regular files that will be called instead.
106 	 */
107 	int (*mknod) (const char *, mode_t, dev_t);
108 
109 	/** Create a directory */
110 	int (*mkdir) (const char *, mode_t);
111 
112 	/** Remove a file */
113 	int (*unlink) (const char *);
114 
115 	/** Remove a directory */
116 	int (*rmdir) (const char *);
117 
118 	/** Create a symbolic link */
119 	int (*symlink) (const char *, const char *);
120 
121 	/** Rename a file */
122 	int (*rename) (const char *, const char *);
123 
124 	/** Create a hard link to a file */
125 	int (*link) (const char *, const char *);
126 
127 	/** Change the permission bits of a file */
128 	int (*chmod) (const char *, mode_t);
129 
130 	/** Change the owner and group of a file */
131 	int (*chown) (const char *, uid_t, gid_t);
132 
133 	/** Change the size of a file */
134 	int (*truncate) (const char *, off_t);
135 
136 	/** Change the access and/or modification times of a file
137 	 *
138 	 * Deprecated, use utimens() instead.
139 	 */
140 	int (*utime) (const char *, struct utimbuf *);
141 
142 	/** File open operation
143 	 *
144 	 * No creation, or truncation flags (O_CREAT, O_EXCL, O_TRUNC)
145 	 * will be passed to open().  Open should check if the operation
146 	 * is permitted for the given flags.  Optionally open may also
147 	 * return an arbitrary filehandle in the fuse_file_info structure,
148 	 * which will be passed to all file operations.
149 	 *
150 	 * Changed in version 2.2
151 	 */
152 	int (*open) (const char *, struct fuse_file_info *);
153 
154 	/** Read data from an open file
155 	 *
156 	 * Read should return exactly the number of bytes requested except
157 	 * on EOF or error, otherwise the rest of the data will be
158 	 * substituted with zeroes.	 An exception to this is when the
159 	 * 'direct_io' mount option is specified, in which case the return
160 	 * value of the read system call will reflect the return value of
161 	 * this operation.
162 	 *
163 	 * Changed in version 2.2
164 	 */
165 	int (*read) (const char *, char *, size_t, off_t,
166 		     struct fuse_file_info *);
167 
168 	/** Write data to an open file
169 	 *
170 	 * Write should return exactly the number of bytes requested
171 	 * except on error.	 An exception to this is when the 'direct_io'
172 	 * mount option is specified (see read operation).
173 	 *
174 	 * Changed in version 2.2
175 	 */
176 	int (*write) (const char *, const char *, size_t, off_t,
177 		      struct fuse_file_info *);
178 
179 	/** Get file system statistics
180 	 *
181 	 * The 'f_frsize', 'f_favail', 'f_fsid' and 'f_flag' fields are ignored
182 	 *
183 	 * Replaced 'struct statfs' parameter with 'struct statvfs' in
184 	 * version 2.5
185 	 */
186 	int (*statfs) (const char *, struct statvfs *);
187 
188 	/** Possibly flush cached data
189 	 *
190 	 * BIG NOTE: This is not equivalent to fsync().  It's not a
191 	 * request to sync dirty data.
192 	 *
193 	 * Flush is called on each close() of a file descriptor.  So if a
194 	 * filesystem wants to return write errors in close() and the file
195 	 * has cached dirty data, this is a good place to write back data
196 	 * and return any errors.  Since many applications ignore close()
197 	 * errors this is not always useful.
198 	 *
199 	 * NOTE: The flush() method may be called more than once for each
200 	 * open().	This happens if more than one file descriptor refers
201 	 * to an opened file due to dup(), dup2() or fork() calls.	It is
202 	 * not possible to determine if a flush is final, so each flush
203 	 * should be treated equally.  Multiple write-flush sequences are
204 	 * relatively rare, so this shouldn't be a problem.
205 	 *
206 	 * Filesystems shouldn't assume that flush will always be called
207 	 * after some writes, or that if will be called at all.
208 	 *
209 	 * Changed in version 2.2
210 	 */
211 	int (*flush) (const char *, struct fuse_file_info *);
212 
213 	/** Release an open file
214 	 *
215 	 * Release is called when there are no more references to an open
216 	 * file: all file descriptors are closed and all memory mappings
217 	 * are unmapped.
218 	 *
219 	 * For every open() call there will be exactly one release() call
220 	 * with the same flags and file descriptor.	 It is possible to
221 	 * have a file opened more than once, in which case only the last
222 	 * release will mean, that no more reads/writes will happen on the
223 	 * file.  The return value of release is ignored.
224 	 *
225 	 * Changed in version 2.2
226 	 */
227 	int (*release) (const char *, struct fuse_file_info *);
228 
229 	/** Synchronize file contents
230 	 *
231 	 * If the datasync parameter is non-zero, then only the user data
232 	 * should be flushed, not the meta data.
233 	 *
234 	 * Changed in version 2.2
235 	 */
236 	int (*fsync) (const char *, int, struct fuse_file_info *);
237 
238 	/** Set extended attributes */
239 	int (*setxattr) (const char *, const char *, const char *, size_t, int);
240 
241 	/** Get extended attributes */
242 	int (*getxattr) (const char *, const char *, char *, size_t);
243 
244 	/** List extended attributes */
245 	int (*listxattr) (const char *, char *, size_t);
246 
247 	/** Remove extended attributes */
248 	int (*removexattr) (const char *, const char *);
249 
250 	/** Open directory
251 	 *
252 	 * This method should check if the open operation is permitted for
253 	 * this  directory
254 	 *
255 	 * Introduced in version 2.3
256 	 */
257 	int (*opendir) (const char *, struct fuse_file_info *);
258 
259 	/** Read directory
260 	 *
261 	 * This supersedes the old getdir() interface.  New applications
262 	 * should use this.
263 	 *
264 	 * The filesystem may choose between two modes of operation:
265 	 *
266 	 * 1) The readdir implementation ignores the offset parameter, and
267 	 * passes zero to the filler function's offset.  The filler
268 	 * function will not return '1' (unless an error happens), so the
269 	 * whole directory is read in a single readdir operation.  This
270 	 * works just like the old getdir() method.
271 	 *
272 	 * 2) The readdir implementation keeps track of the offsets of the
273 	 * directory entries.  It uses the offset parameter and always
274 	 * passes non-zero offset to the filler function.  When the buffer
275 	 * is full (or an error happens) the filler function will return
276 	 * '1'.
277 	 *
278 	 * Introduced in version 2.3
279 	 */
280 	int (*readdir) (const char *, void *, fuse_fill_dir_t, off_t,
281 			struct fuse_file_info *);
282 
283 	/** Release directory
284 	 *
285 	 * Introduced in version 2.3
286 	 */
287 	int (*releasedir) (const char *, struct fuse_file_info *);
288 
289 	/** Synchronize directory contents
290 	 *
291 	 * If the datasync parameter is non-zero, then only the user data
292 	 * should be flushed, not the meta data
293 	 *
294 	 * Introduced in version 2.3
295 	 */
296 	int (*fsyncdir) (const char *, int, struct fuse_file_info *);
297 
298 	/**
299 	 * Initialize filesystem
300 	 *
301 	 * The return value will passed in the private_data field of
302 	 * fuse_context to all file operations and as a parameter to the
303 	 * destroy() method.
304 	 *
305 	 * Introduced in version 2.3
306 	 * Changed in version 2.6
307 	 */
308 	void *(*init) (struct fuse_conn_info *conn);
309 
310 	/**
311 	 * Clean up filesystem
312 	 *
313 	 * Called on filesystem exit.
314 	 *
315 	 * Introduced in version 2.3
316 	 */
317 	void (*destroy) (void *);
318 
319 	/**
320 	 * Check file access permissions
321 	 *
322 	 * This will be called for the access() system call.  If the
323 	 * 'default_permissions' mount option is given, this method is not
324 	 * called.
325 	 *
326 	 * This method is not called under Linux kernel versions 2.4.x
327 	 *
328 	 * Introduced in version 2.5
329 	 */
330 	int (*access) (const char *, int);
331 
332 	/**
333 	 * Create and open a file
334 	 *
335 	 * If the file does not exist, first create it with the specified
336 	 * mode, and then open it.
337 	 *
338 	 * If this method is not implemented or under Linux kernel
339 	 * versions earlier than 2.6.15, the mknod() and open() methods
340 	 * will be called instead.
341 	 *
342 	 * Introduced in version 2.5
343 	 */
344 	int (*create) (const char *, mode_t, struct fuse_file_info *);
345 
346 	/**
347 	 * Change the size of an open file
348 	 *
349 	 * This method is called instead of the truncate() method if the
350 	 * truncation was invoked from an ftruncate() system call.
351 	 *
352 	 * If this method is not implemented or under Linux kernel
353 	 * versions earlier than 2.6.15, the truncate() method will be
354 	 * called instead.
355 	 *
356 	 * Introduced in version 2.5
357 	 */
358 	int (*ftruncate) (const char *, off_t, struct fuse_file_info *);
359 
360 	/**
361 	 * Get attributes from an open file
362 	 *
363 	 * This method is called instead of the getattr() method if the
364 	 * file information is available.
365 	 *
366 	 * Currently this is only called after the create() method if that
367 	 * is implemented (see above).  Later it may be called for
368 	 * invocations of fstat() too.
369 	 *
370 	 * Introduced in version 2.5
371 	 */
372 	int (*fgetattr) (const char *, struct stat *, struct fuse_file_info *);
373 
374 	/**
375 	 * Perform POSIX file locking operation
376 	 *
377 	 * The cmd argument will be either F_GETLK, F_SETLK or F_SETLKW.
378 	 *
379 	 * For the meaning of fields in 'struct flock' see the man page
380 	 * for fcntl(2).  The l_whence field will always be set to
381 	 * SEEK_SET.
382 	 *
383 	 * For checking lock ownership, the 'fuse_file_info->owner'
384 	 * argument must be used.
385 	 *
386 	 * For F_GETLK operation, the library will first check currently
387 	 * held locks, and if a conflicting lock is found it will return
388 	 * information without calling this method.	 This ensures, that
389 	 * for local locks the l_pid field is correctly filled in.	The
390 	 * results may not be accurate in case of race conditions and in
391 	 * the presence of hard links, but it's unlikly that an
392 	 * application would rely on accurate GETLK results in these
393 	 * cases.  If a conflicting lock is not found, this method will be
394 	 * called, and the filesystem may fill out l_pid by a meaningful
395 	 * value, or it may leave this field zero.
396 	 *
397 	 * For F_SETLK and F_SETLKW the l_pid field will be set to the pid
398 	 * of the process performing the locking operation.
399 	 *
400 	 * Note: if this method is not implemented, the kernel will still
401 	 * allow file locking to work locally.  Hence it is only
402 	 * interesting for network filesystems and similar.
403 	 *
404 	 * Introduced in version 2.6
405 	 */
406 	int (*lock) (const char *, struct fuse_file_info *, int cmd,
407 		     struct flock *);
408 
409 	/**
410 	 * Change the access and modification times of a file with
411 	 * nanosecond resolution
412 	 *
413 	 * Introduced in version 2.6
414 	 */
415 	int (*utimens) (const char *, const struct timespec tv[2]);
416 
417 	/**
418 	 * Map block index within file to block index within device
419 	 *
420 	 * Note: This makes sense only for block device backed filesystems
421 	 * mounted with the 'blkdev' option
422 	 *
423 	 * Introduced in version 2.6
424 	 */
425 	int (*bmap) (const char *, size_t blocksize, uint64_t *idx);
426 };
427 
428 /** Extra context that may be needed by some filesystems
429  *
430  * The uid, gid and pid fields are not filled in case of a writepage
431  * operation.
432  */
433 struct fuse_context {
434 	/** Pointer to the fuse object */
435 	struct fuse *fuse;
436 
437 	/** User ID of the calling process */
438 	uid_t uid;
439 
440 	/** Group ID of the calling process */
441 	gid_t gid;
442 
443 	/** Thread ID of the calling process */
444 	pid_t pid;
445 
446 	/** Private filesystem data */
447 	void *private_data;
448 };
449 
450 /**
451  * Main function of FUSE.
452  *
453  * This is for the lazy.  This is all that has to be called from the
454  * main() function.
455  *
456  * This function does the following:
457  *   - parses command line options (-d -s and -h)
458  *   - passes relevant mount options to the fuse_mount()
459  *   - installs signal handlers for INT, HUP, TERM and PIPE
460  *   - registers an exit handler to unmount the filesystem on program exit
461  *   - creates a fuse handle
462  *   - registers the operations
463  *   - calls either the single-threaded or the multi-threaded event loop
464  *
465  * Note: this is currently implemented as a macro.
466  *
467  * @param argc the argument counter passed to the main() function
468  * @param argv the argument vector passed to the main() function
469  * @param op the file system operation
470  * @param user_data user data supplied in the context during the init() method
471  * @return 0 on success, nonzero on failure
472  */
473 /*
474   int fuse_main(int argc, char *argv[], const struct fuse_operations *op,
475   void *user_data);
476 */
477 #define fuse_main(argc, argv, op, user_data)				\
478 	fuse_main_real(argc, argv, op, sizeof(*(op)), user_data)
479 
480 /* ----------------------------------------------------------- *
481  * More detailed API					       *
482  * ----------------------------------------------------------- */
483 
484 /**
485  * Create a new FUSE filesystem.
486  *
487  * @param ch the communication channel
488  * @param args argument vector
489  * @param op the filesystem operations
490  * @param op_size the size of the fuse_operations structure
491  * @param user_data user data supplied in the context during the init() method
492  * @return the created FUSE handle
493  */
494 struct fuse *fuse_new(struct fuse_chan *ch, struct fuse_args *args,
495 		      const struct fuse_operations *op, size_t op_size,
496 		      void *user_data);
497 
498 /**
499  * Destroy the FUSE handle.
500  *
501  * The communication channel attached to the handle is also destroyed.
502  *
503  * NOTE: This function does not unmount the filesystem.	 If this is
504  * needed, call fuse_unmount() before calling this function.
505  *
506  * @param f the FUSE handle
507  */
508 void fuse_destroy(struct fuse *f);
509 
510 /**
511  * FUSE event loop.
512  *
513  * Requests from the kernel are processed, and the appropriate
514  * operations are called.
515  *
516  * @param f the FUSE handle
517  * @return 0 if no error occurred, -1 otherwise
518  */
519 int fuse_loop(struct fuse *f);
520 
521 /**
522  * Exit from event loop
523  *
524  * @param f the FUSE handle
525  */
526 void fuse_exit(struct fuse *f);
527 
528 /**
529  * FUSE event loop with multiple threads
530  *
531  * Requests from the kernel are processed, and the appropriate
532  * operations are called.  Request are processed in parallel by
533  * distributing them between multiple threads.
534  *
535  * Calling this function requires the pthreads library to be linked to
536  * the application.
537  *
538  * @param f the FUSE handle
539  * @return 0 if no error occurred, -1 otherwise
540  */
541 int fuse_loop_mt(struct fuse *f);
542 
543 /**
544  * Get the current context
545  *
546  * The context is only valid for the duration of a filesystem
547  * operation, and thus must not be stored and used later.
548  *
549  * @return the context
550  */
551 struct fuse_context *fuse_get_context(void);
552 
553 /**
554  * Check if a request has already been interrupted
555  *
556  * @param req request handle
557  * @return 1 if the request has been interrupted, 0 otherwise
558  */
559 int fuse_interrupted(void);
560 
561 /**
562  * Obsolete, doesn't do anything
563  *
564  * @return -EINVAL
565  */
566 int fuse_invalidate(struct fuse *f, const char *path);
567 
568 /* Deprecated, don't use */
569 int fuse_is_lib_option(const char *opt);
570 
571 /**
572  * The real main function
573  *
574  * Do not call this directly, use fuse_main()
575  */
576 int fuse_main_real(int argc, char *argv[], const struct fuse_operations *op,
577 		   size_t op_size, void *user_data);
578 
579 /*
580  * Stacking API
581  */
582 
583 /**
584  * Fuse filesystem object
585  *
586  * This is opaque object represents a filesystem layer
587  */
588 struct fuse_fs;
589 
590 /*
591  * These functions call the relevant filesystem operation, and return
592  * the result.
593  *
594  * If the operation is not defined, they return -ENOSYS, with the
595  * exception of fuse_fs_open, fuse_fs_release, fuse_fs_opendir,
596  * fuse_fs_releasedir and fuse_fs_statfs, which return 0.
597  */
598 
599 int fuse_fs_getattr(struct fuse_fs *fs, const char *path, struct stat *buf);
600 int fuse_fs_fgetattr(struct fuse_fs *fs, const char *path, struct stat *buf,
601 		     struct fuse_file_info *fi);
602 int fuse_fs_rename(struct fuse_fs *fs, const char *oldpath,
603 		   const char *newpath);
604 int fuse_fs_unlink(struct fuse_fs *fs, const char *path);
605 int fuse_fs_rmdir(struct fuse_fs *fs, const char *path);
606 int fuse_fs_symlink(struct fuse_fs *fs, const char *linkname,
607 		    const char *path);
608 int fuse_fs_link(struct fuse_fs *fs, const char *oldpath, const char *newpath);
609 int fuse_fs_release(struct fuse_fs *fs,	 const char *path,
610 		    struct fuse_file_info *fi);
611 int fuse_fs_open(struct fuse_fs *fs, const char *path,
612 		 struct fuse_file_info *fi);
613 int fuse_fs_read(struct fuse_fs *fs, const char *path, char *buf, size_t size,
614 		 off_t off, struct fuse_file_info *fi);
615 int fuse_fs_write(struct fuse_fs *fs, const char *path, const char *buf,
616 		  size_t size, off_t off, struct fuse_file_info *fi);
617 int fuse_fs_fsync(struct fuse_fs *fs, const char *path, int datasync,
618 		  struct fuse_file_info *fi);
619 int fuse_fs_flush(struct fuse_fs *fs, const char *path,
620 		  struct fuse_file_info *fi);
621 int fuse_fs_statfs(struct fuse_fs *fs, const char *path, struct statvfs *buf);
622 int fuse_fs_opendir(struct fuse_fs *fs, const char *path,
623 		    struct fuse_file_info *fi);
624 int fuse_fs_readdir(struct fuse_fs *fs, const char *path, void *buf,
625 		    fuse_fill_dir_t filler, off_t off,
626 		    struct fuse_file_info *fi);
627 int fuse_fs_fsyncdir(struct fuse_fs *fs, const char *path, int datasync,
628 		     struct fuse_file_info *fi);
629 int fuse_fs_releasedir(struct fuse_fs *fs, const char *path,
630 		       struct fuse_file_info *fi);
631 int fuse_fs_create(struct fuse_fs *fs, const char *path, mode_t mode,
632 		   struct fuse_file_info *fi);
633 int fuse_fs_lock(struct fuse_fs *fs, const char *path,
634 		 struct fuse_file_info *fi, int cmd, struct flock *lock);
635 int fuse_fs_chmod(struct fuse_fs *fs, const char *path, mode_t mode);
636 int fuse_fs_chown(struct fuse_fs *fs, const char *path, uid_t uid, gid_t gid);
637 int fuse_fs_truncate(struct fuse_fs *fs, const char *path, off_t size);
638 int fuse_fs_ftruncate(struct fuse_fs *fs, const char *path, off_t size,
639 		      struct fuse_file_info *fi);
640 int fuse_fs_utimens(struct fuse_fs *fs, const char *path,
641 		    const struct timespec tv[2]);
642 int fuse_fs_access(struct fuse_fs *fs, const char *path, int mask);
643 int fuse_fs_readlink(struct fuse_fs *fs, const char *path, char *buf,
644 		     size_t len);
645 int fuse_fs_mknod(struct fuse_fs *fs, const char *path, mode_t mode,
646 		  dev_t rdev);
647 int fuse_fs_mkdir(struct fuse_fs *fs, const char *path, mode_t mode);
648 int fuse_fs_setxattr(struct fuse_fs *fs, const char *path, const char *name,
649 		     const char *value, size_t size, int flags);
650 int fuse_fs_getxattr(struct fuse_fs *fs, const char *path, const char *name,
651 		     char *value, size_t size);
652 int fuse_fs_listxattr(struct fuse_fs *fs, const char *path, char *list,
653 		      size_t size);
654 int fuse_fs_removexattr(struct fuse_fs *fs, const char *path,
655 			const char *name);
656 int fuse_fs_bmap(struct fuse_fs *fs, const char *path, size_t blocksize,
657 		 uint64_t *idx);
658 void fuse_fs_init(struct fuse_fs *fs, struct fuse_conn_info *conn);
659 void fuse_fs_destroy(struct fuse_fs *fs);
660 
661 /**
662  * Create a new fuse filesystem object
663  *
664  * This is usually called from the factory of a fuse module to create
665  * a new instance of a filesystem.
666  *
667  * @param op the filesystem operations
668  * @param op_size the size of the fuse_operations structure
669  * @param user_data user data supplied in the context during the init() method
670  * @return a new filesystem object
671  */
672 struct fuse_fs *fuse_fs_new(const struct fuse_operations *op, size_t op_size,
673 			    void *user_data);
674 
675 /**
676  * Filesystem module
677  *
678  * Filesystem modules are registered with the FUSE_REGISTER_MODULE()
679  * macro.
680  *
681  * If the "-omodules=modname:..." option is present, filesystem
682  * objects are created and pushed onto the stack with the 'factory'
683  * function.
684  */
685 struct fuse_module {
686 	/**
687 	 * Name of filesystem
688 	 */
689 	const char *name;
690 
691 	/**
692 	 * Factory for creating filesystem objects
693 	 *
694 	 * The function may use and remove options from 'args' that belong
695 	 * to this module.
696 	 *
697 	 * For now the 'fs' vector always contains exactly one filesystem.
698 	 * This is the filesystem which will be below the newly created
699 	 * filesystem in the stack.
700 	 *
701 	 * @param args the command line arguments
702 	 * @param fs NULL terminated filesystem object vector
703 	 * @return the new filesystem object
704 	 */
705 	struct fuse_fs *(*factory)(struct fuse_args *args,
706 				   struct fuse_fs *fs[]);
707 
708 	struct fuse_module *next;
709 	struct fusemod_so *so;
710 	int ctr;
711 };
712 
713 /**
714  * Register a filesystem module
715  *
716  * This function is used by FUSE_REGISTER_MODULE and there's usually
717  * no need to call it directly
718  */
719 void fuse_register_module(struct fuse_module *mod);
720 
721 /**
722  * Register filesystem module
723  *
724  * For the parameters, see description of the fields in 'struct
725  * fuse_module'
726  */
727 #define FUSE_REGISTER_MODULE(name_, factory_)				  \
728 	static __attribute__((constructor)) void name_ ## _register(void) \
729 	{								  \
730 		static struct fuse_module mod =				  \
731 			{ #name_, factory_, NULL, NULL, 0 };		  \
732 		fuse_register_module(&mod);				  \
733 	}
734 
735 
736 /* ----------------------------------------------------------- *
737  * Advanced API for event handling, don't worry about this...  *
738  * ----------------------------------------------------------- */
739 
740 /* NOTE: the following functions are deprecated, and will be removed
741    from the 3.0 API.  Use the lowlevel session functions instead */
742 
743 /** Function type used to process commands */
744 typedef void (*fuse_processor_t)(struct fuse *, struct fuse_cmd *, void *);
745 
746 /** This is the part of fuse_main() before the event loop */
747 struct fuse *fuse_setup(int argc, char *argv[],
748 			const struct fuse_operations *op, size_t op_size,
749 			char **mountpoint, int *multithreaded,
750 			void *user_data);
751 
752 /** This is the part of fuse_main() after the event loop */
753 void fuse_teardown(struct fuse *fuse, char *mountpoint);
754 
755 /** Read a single command.  If none are read, return NULL */
756 struct fuse_cmd *fuse_read_cmd(struct fuse *f);
757 
758 /** Process a single command */
759 void fuse_process_cmd(struct fuse *f, struct fuse_cmd *cmd);
760 
761 /** Multi threaded event loop, which calls the custom command
762     processor function */
763 int fuse_loop_mt_proc(struct fuse *f, fuse_processor_t proc, void *data);
764 
765 /** Return the exited flag, which indicates if fuse_exit() has been
766     called */
767 int fuse_exited(struct fuse *f);
768 
769 /** This function is obsolete and implemented as a no-op */
770 void fuse_set_getcontext_func(struct fuse_context *(*func)(void));
771 
772 /** Get session from fuse object */
773 struct fuse_session *fuse_get_session(struct fuse *f);
774 
775 /* ----------------------------------------------------------- *
776  * Compatibility stuff					       *
777  * ----------------------------------------------------------- */
778 
779 #if FUSE_USE_VERSION < 26
780 #  include "fuse_compat.h"
781 #  undef fuse_main
782 #  if FUSE_USE_VERSION == 25
783 #    define fuse_main(argc, argv, op)				\
784 	fuse_main_real_compat25(argc, argv, op, sizeof(*(op)))
785 #    define fuse_new fuse_new_compat25
786 #    define fuse_setup fuse_setup_compat25
787 #    define fuse_teardown fuse_teardown_compat22
788 #    define fuse_operations fuse_operations_compat25
789 #  elif FUSE_USE_VERSION == 22
790 #    define fuse_main(argc, argv, op)				\
791 	fuse_main_real_compat22(argc, argv, op, sizeof(*(op)))
792 #    define fuse_new fuse_new_compat22
793 #    define fuse_setup fuse_setup_compat22
794 #    define fuse_teardown fuse_teardown_compat22
795 #    define fuse_operations fuse_operations_compat22
796 #    define fuse_file_info fuse_file_info_compat
797 #  elif FUSE_USE_VERSION == 24
798 #    error Compatibility with high-level API version 24 not supported
799 #  else
800 #    define fuse_dirfil_t fuse_dirfil_t_compat
801 #    define __fuse_read_cmd fuse_read_cmd
802 #    define __fuse_process_cmd fuse_process_cmd
803 #    define __fuse_loop_mt fuse_loop_mt_proc
804 #    if FUSE_USE_VERSION == 21
805 #      define fuse_operations fuse_operations_compat2
806 #      define fuse_main fuse_main_compat2
807 #      define fuse_new fuse_new_compat2
808 #      define __fuse_setup fuse_setup_compat2
809 #      define __fuse_teardown fuse_teardown_compat22
810 #      define __fuse_exited fuse_exited
811 #      define __fuse_set_getcontext_func fuse_set_getcontext_func
812 #    else
813 #      define fuse_statfs fuse_statfs_compat1
814 #      define fuse_operations fuse_operations_compat1
815 #      define fuse_main fuse_main_compat1
816 #      define fuse_new fuse_new_compat1
817 #      define FUSE_DEBUG FUSE_DEBUG_COMPAT1
818 #    endif
819 #  endif
820 #endif
821 
822 #ifdef __cplusplus
823 }
824 #endif
825 
826 #endif /* _FUSE_H_ */
827