libfuse
helper.c
1 /*
2  FUSE: Filesystem in Userspace
3  Copyright (C) 2001-2007 Miklos Szeredi <miklos@szeredi.hu>
4 
5  Helper functions to create (simple) standalone programs. With the
6  aid of these functions it should be possible to create full FUSE
7  file system by implementing nothing but the request handlers.
8 
9  This program can be distributed under the terms of the GNU LGPLv2.
10  See the file COPYING.LIB.
11 */
12 
13 #include "fuse_config.h"
14 #include "fuse_i.h"
15 #include "fuse_misc.h"
16 #include "fuse_opt.h"
17 #include "fuse_lowlevel.h"
18 #include "mount_util.h"
19 
20 #include <stdio.h>
21 #include <stdlib.h>
22 #include <stddef.h>
23 #include <unistd.h>
24 #include <string.h>
25 #include <limits.h>
26 #include <errno.h>
27 #include <sys/param.h>
28 
29 #define FUSE_HELPER_OPT(t, p) \
30  { t, offsetof(struct fuse_cmdline_opts, p), 1 }
31 
32 static const struct fuse_opt fuse_helper_opts[] = {
33  FUSE_HELPER_OPT("-h", show_help),
34  FUSE_HELPER_OPT("--help", show_help),
35  FUSE_HELPER_OPT("-V", show_version),
36  FUSE_HELPER_OPT("--version", show_version),
37  FUSE_HELPER_OPT("-d", debug),
38  FUSE_HELPER_OPT("debug", debug),
39  FUSE_HELPER_OPT("-d", foreground),
40  FUSE_HELPER_OPT("debug", foreground),
43  FUSE_HELPER_OPT("-f", foreground),
44  FUSE_HELPER_OPT("-s", singlethread),
45  FUSE_HELPER_OPT("fsname=", nodefault_subtype),
46  FUSE_OPT_KEY("fsname=", FUSE_OPT_KEY_KEEP),
47 #ifndef __FreeBSD__
48  FUSE_HELPER_OPT("subtype=", nodefault_subtype),
49  FUSE_OPT_KEY("subtype=", FUSE_OPT_KEY_KEEP),
50 #endif
51  FUSE_HELPER_OPT("clone_fd", clone_fd),
52  FUSE_HELPER_OPT("max_idle_threads=%u", max_idle_threads),
53  FUSE_HELPER_OPT("max_threads=%u", max_threads),
55 };
56 
57 struct fuse_conn_info_opts {
58  int atomic_o_trunc;
59  int no_remote_posix_lock;
60  int no_remote_flock;
61  int splice_write;
62  int splice_move;
63  int splice_read;
64  int no_splice_write;
65  int no_splice_move;
66  int no_splice_read;
67  int auto_inval_data;
68  int no_auto_inval_data;
69  int no_readdirplus;
70  int no_readdirplus_auto;
71  int async_dio;
72  int no_async_dio;
73  int writeback_cache;
74  int no_writeback_cache;
75  int async_read;
76  int sync_read;
77  unsigned max_write;
78  unsigned max_readahead;
79  unsigned max_background;
80  unsigned congestion_threshold;
81  unsigned time_gran;
82  int set_max_write;
83  int set_max_readahead;
84  int set_max_background;
85  int set_congestion_threshold;
86  int set_time_gran;
87 };
88 
89 #define CONN_OPTION(t, p, v) \
90  { t, offsetof(struct fuse_conn_info_opts, p), v }
91 static const struct fuse_opt conn_info_opt_spec[] = {
92  CONN_OPTION("max_write=%u", max_write, 0),
93  CONN_OPTION("max_write=", set_max_write, 1),
94  CONN_OPTION("max_readahead=%u", max_readahead, 0),
95  CONN_OPTION("max_readahead=", set_max_readahead, 1),
96  CONN_OPTION("max_background=%u", max_background, 0),
97  CONN_OPTION("max_background=", set_max_background, 1),
98  CONN_OPTION("congestion_threshold=%u", congestion_threshold, 0),
99  CONN_OPTION("congestion_threshold=", set_congestion_threshold, 1),
100  CONN_OPTION("sync_read", sync_read, 1),
101  CONN_OPTION("async_read", async_read, 1),
102  CONN_OPTION("atomic_o_trunc", atomic_o_trunc, 1),
103  CONN_OPTION("no_remote_lock", no_remote_posix_lock, 1),
104  CONN_OPTION("no_remote_lock", no_remote_flock, 1),
105  CONN_OPTION("no_remote_flock", no_remote_flock, 1),
106  CONN_OPTION("no_remote_posix_lock", no_remote_posix_lock, 1),
107  CONN_OPTION("splice_write", splice_write, 1),
108  CONN_OPTION("no_splice_write", no_splice_write, 1),
109  CONN_OPTION("splice_move", splice_move, 1),
110  CONN_OPTION("no_splice_move", no_splice_move, 1),
111  CONN_OPTION("splice_read", splice_read, 1),
112  CONN_OPTION("no_splice_read", no_splice_read, 1),
113  CONN_OPTION("auto_inval_data", auto_inval_data, 1),
114  CONN_OPTION("no_auto_inval_data", no_auto_inval_data, 1),
115  CONN_OPTION("readdirplus=no", no_readdirplus, 1),
116  CONN_OPTION("readdirplus=yes", no_readdirplus, 0),
117  CONN_OPTION("readdirplus=yes", no_readdirplus_auto, 1),
118  CONN_OPTION("readdirplus=auto", no_readdirplus, 0),
119  CONN_OPTION("readdirplus=auto", no_readdirplus_auto, 0),
120  CONN_OPTION("async_dio", async_dio, 1),
121  CONN_OPTION("no_async_dio", no_async_dio, 1),
122  CONN_OPTION("writeback_cache", writeback_cache, 1),
123  CONN_OPTION("no_writeback_cache", no_writeback_cache, 1),
124  CONN_OPTION("time_gran=%u", time_gran, 0),
125  CONN_OPTION("time_gran=", set_time_gran, 1),
127 };
128 
129 
130 void fuse_cmdline_help(void)
131 {
132  printf(" -h --help print help\n"
133  " -V --version print version\n"
134  " -d -o debug enable debug output (implies -f)\n"
135  " -f foreground operation\n"
136  " -s disable multi-threaded operation\n"
137  " -o clone_fd use separate fuse device fd for each thread\n"
138  " (may improve performance)\n"
139  " -o max_idle_threads the maximum number of idle worker threads\n"
140  " allowed (default: -1)\n"
141  " -o max_threads the maximum number of worker threads\n"
142  " allowed (default: 10)\n");
143 }
144 
145 static int fuse_helper_opt_proc(void *data, const char *arg, int key,
146  struct fuse_args *outargs)
147 {
148  (void) outargs;
149  struct fuse_cmdline_opts *opts = data;
150 
151  switch (key) {
152  case FUSE_OPT_KEY_NONOPT:
153  if (!opts->mountpoint) {
154  if (fuse_mnt_parse_fuse_fd(arg) != -1) {
155  return fuse_opt_add_opt(&opts->mountpoint, arg);
156  }
157 
158  char mountpoint[PATH_MAX] = "";
159  if (realpath(arg, mountpoint) == NULL) {
160  fuse_log(FUSE_LOG_ERR,
161  "fuse: bad mount point `%s': %s\n",
162  arg, strerror(errno));
163  return -1;
164  }
165  return fuse_opt_add_opt(&opts->mountpoint, mountpoint);
166  } else {
167  fuse_log(FUSE_LOG_ERR, "fuse: invalid argument `%s'\n", arg);
168  return -1;
169  }
170 
171  default:
172  /* Pass through unknown options */
173  return 1;
174  }
175 }
176 
177 /* Under FreeBSD, there is no subtype option so this
178  function actually sets the fsname */
179 static int add_default_subtype(const char *progname, struct fuse_args *args)
180 {
181  int res;
182  char *subtype_opt;
183 
184  const char *basename = strrchr(progname, '/');
185  if (basename == NULL)
186  basename = progname;
187  else if (basename[1] != '\0')
188  basename++;
189 
190  subtype_opt = (char *) malloc(strlen(basename) + 64);
191  if (subtype_opt == NULL) {
192  fuse_log(FUSE_LOG_ERR, "fuse: memory allocation failed\n");
193  return -1;
194  }
195 #ifdef __FreeBSD__
196  sprintf(subtype_opt, "-ofsname=%s", basename);
197 #else
198  sprintf(subtype_opt, "-osubtype=%s", basename);
199 #endif
200  res = fuse_opt_add_arg(args, subtype_opt);
201  free(subtype_opt);
202  return res;
203 }
204 
205 int fuse_parse_cmdline_312(struct fuse_args *args,
206  struct fuse_cmdline_opts *opts);
207 FUSE_SYMVER("fuse_parse_cmdline_312", "fuse_parse_cmdline@@FUSE_3.12")
208 int fuse_parse_cmdline_312(struct fuse_args *args,
209  struct fuse_cmdline_opts *opts)
210 {
211  memset(opts, 0, sizeof(struct fuse_cmdline_opts));
212 
213  opts->max_idle_threads = UINT_MAX; /* new default in fuse version 3.12 */
214  opts->max_threads = 10;
215 
216  if (fuse_opt_parse(args, opts, fuse_helper_opts,
217  fuse_helper_opt_proc) == -1)
218  return -1;
219 
220  /* *Linux*: if neither -o subtype nor -o fsname are specified,
221  set subtype to program's basename.
222  *FreeBSD*: if fsname is not specified, set to program's
223  basename. */
224  if (!opts->nodefault_subtype)
225  if (add_default_subtype(args->argv[0], args) == -1)
226  return -1;
227 
228  return 0;
229 }
230 
234 int fuse_parse_cmdline_30(struct fuse_args *args,
235  struct fuse_cmdline_opts *opts);
236 FUSE_SYMVER("fuse_parse_cmdline_30", "fuse_parse_cmdline@FUSE_3.0")
237 int fuse_parse_cmdline_30(struct fuse_args *args,
238  struct fuse_cmdline_opts *out_opts)
239 {
240  struct fuse_cmdline_opts opts;
241 
242  int rc = fuse_parse_cmdline_312(args, &opts);
243  if (rc == 0) {
244  /* copy up to the size of the old pre 3.12 struct */
245  memcpy(out_opts, &opts,
246  offsetof(struct fuse_cmdline_opts, max_idle_threads) +
247  sizeof(opts.max_idle_threads));
248  }
249 
250  return rc;
251 }
252 
253 int fuse_daemonize(int foreground)
254 {
255  if (!foreground) {
256  int nullfd;
257  int waiter[2];
258  char completed;
259 
260  if (pipe(waiter)) {
261  perror("fuse_daemonize: pipe");
262  return -1;
263  }
264 
265  /*
266  * demonize current process by forking it and killing the
267  * parent. This makes current process as a child of 'init'.
268  */
269  switch(fork()) {
270  case -1:
271  perror("fuse_daemonize: fork");
272  return -1;
273  case 0:
274  break;
275  default:
276  (void) read(waiter[0], &completed, sizeof(completed));
277  _exit(0);
278  }
279 
280  if (setsid() == -1) {
281  perror("fuse_daemonize: setsid");
282  return -1;
283  }
284 
285  (void) chdir("/");
286 
287  nullfd = open("/dev/null", O_RDWR, 0);
288  if (nullfd != -1) {
289  (void) dup2(nullfd, 0);
290  (void) dup2(nullfd, 1);
291  (void) dup2(nullfd, 2);
292  if (nullfd > 2)
293  close(nullfd);
294  }
295 
296  /* Propagate completion of daemon initialization */
297  completed = 1;
298  (void) write(waiter[1], &completed, sizeof(completed));
299  close(waiter[0]);
300  close(waiter[1]);
301  } else {
302  (void) chdir("/");
303  }
304  return 0;
305 }
306 
307 int fuse_main_real(int argc, char *argv[], const struct fuse_operations *op,
308  size_t op_size, void *user_data)
309 {
310  struct fuse_args args = FUSE_ARGS_INIT(argc, argv);
311  struct fuse *fuse;
312  struct fuse_cmdline_opts opts;
313  int res;
314  struct fuse_loop_config *loop_config = NULL;
315 
316  if (fuse_parse_cmdline(&args, &opts) != 0)
317  return 1;
318 
319  if (opts.show_version) {
320  printf("FUSE library version %s\n", PACKAGE_VERSION);
322  res = 0;
323  goto out1;
324  }
325 
326  if (opts.show_help) {
327  if(args.argv[0][0] != '\0')
328  printf("usage: %s [options] <mountpoint>\n\n",
329  args.argv[0]);
330  printf("FUSE options:\n");
332  fuse_lib_help(&args);
333  res = 0;
334  goto out1;
335  }
336 
337  if (!opts.show_help &&
338  !opts.mountpoint) {
339  fuse_log(FUSE_LOG_ERR, "error: no mountpoint specified\n");
340  res = 2;
341  goto out1;
342  }
343 
344 
345  fuse = fuse_new_31(&args, op, op_size, user_data);
346  if (fuse == NULL) {
347  res = 3;
348  goto out1;
349  }
350 
351  if (fuse_mount(fuse,opts.mountpoint) != 0) {
352  res = 4;
353  goto out2;
354  }
355 
356  if (fuse_daemonize(opts.foreground) != 0) {
357  res = 5;
358  goto out3;
359  }
360 
361  struct fuse_session *se = fuse_get_session(fuse);
362  if (fuse_set_signal_handlers(se) != 0) {
363  res = 6;
364  goto out3;
365  }
366 
367  if (opts.singlethread)
368  res = fuse_loop(fuse);
369  else {
370  loop_config = fuse_loop_cfg_create();
371  if (loop_config == NULL) {
372  res = 7;
373  goto out3;
374  }
375 
376  fuse_loop_cfg_set_clone_fd(loop_config, opts.clone_fd);
377 
378  fuse_loop_cfg_set_idle_threads(loop_config, opts.max_idle_threads);
379  fuse_loop_cfg_set_max_threads(loop_config, opts.max_threads);
380  res = fuse_loop_mt(fuse, loop_config);
381  }
382  if (res)
383  res = 8;
384 
386 out3:
387  fuse_unmount(fuse);
388 out2:
389  fuse_destroy(fuse);
390 out1:
391  fuse_loop_cfg_destroy(loop_config);
392  free(opts.mountpoint);
393  fuse_opt_free_args(&args);
394  return res;
395 }
396 
397 
398 void fuse_apply_conn_info_opts(struct fuse_conn_info_opts *opts,
399  struct fuse_conn_info *conn)
400 {
401  if(opts->set_max_write)
402  conn->max_write = opts->max_write;
403  if(opts->set_max_background)
404  conn->max_background = opts->max_background;
405  if(opts->set_congestion_threshold)
406  conn->congestion_threshold = opts->congestion_threshold;
407  if(opts->set_time_gran)
408  conn->time_gran = opts->time_gran;
409  if(opts->set_max_readahead)
410  conn->max_readahead = opts->max_readahead;
411 
412 #define LL_ENABLE(cond,cap) \
413  if (cond) conn->want |= (cap)
414 #define LL_DISABLE(cond,cap) \
415  if (cond) conn->want &= ~(cap)
416 
417  LL_ENABLE(opts->splice_read, FUSE_CAP_SPLICE_READ);
418  LL_DISABLE(opts->no_splice_read, FUSE_CAP_SPLICE_READ);
419 
420  LL_ENABLE(opts->splice_write, FUSE_CAP_SPLICE_WRITE);
421  LL_DISABLE(opts->no_splice_write, FUSE_CAP_SPLICE_WRITE);
422 
423  LL_ENABLE(opts->splice_move, FUSE_CAP_SPLICE_MOVE);
424  LL_DISABLE(opts->no_splice_move, FUSE_CAP_SPLICE_MOVE);
425 
426  LL_ENABLE(opts->auto_inval_data, FUSE_CAP_AUTO_INVAL_DATA);
427  LL_DISABLE(opts->no_auto_inval_data, FUSE_CAP_AUTO_INVAL_DATA);
428 
429  LL_DISABLE(opts->no_readdirplus, FUSE_CAP_READDIRPLUS);
430  LL_DISABLE(opts->no_readdirplus_auto, FUSE_CAP_READDIRPLUS_AUTO);
431 
432  LL_ENABLE(opts->async_dio, FUSE_CAP_ASYNC_DIO);
433  LL_DISABLE(opts->no_async_dio, FUSE_CAP_ASYNC_DIO);
434 
435  LL_ENABLE(opts->writeback_cache, FUSE_CAP_WRITEBACK_CACHE);
436  LL_DISABLE(opts->no_writeback_cache, FUSE_CAP_WRITEBACK_CACHE);
437 
438  LL_ENABLE(opts->async_read, FUSE_CAP_ASYNC_READ);
439  LL_DISABLE(opts->sync_read, FUSE_CAP_ASYNC_READ);
440 
441  LL_DISABLE(opts->no_remote_posix_lock, FUSE_CAP_POSIX_LOCKS);
442  LL_DISABLE(opts->no_remote_flock, FUSE_CAP_FLOCK_LOCKS);
443 }
444 
445 struct fuse_conn_info_opts* fuse_parse_conn_info_opts(struct fuse_args *args)
446 {
447  struct fuse_conn_info_opts *opts;
448 
449  opts = calloc(1, sizeof(struct fuse_conn_info_opts));
450  if(opts == NULL) {
451  fuse_log(FUSE_LOG_ERR, "calloc failed\n");
452  return NULL;
453  }
454  if(fuse_opt_parse(args, opts, conn_info_opt_spec, NULL) == -1) {
455  free(opts);
456  return NULL;
457  }
458  return opts;
459 }
460 
461 int fuse_open_channel(const char *mountpoint, const char* options)
462 {
463  struct mount_opts *opts = NULL;
464  int fd = -1;
465  const char *argv[] = { "", "-o", options };
466  int argc = sizeof(argv) / sizeof(argv[0]);
467  struct fuse_args args = FUSE_ARGS_INIT(argc, (char**) argv);
468 
469  opts = parse_mount_opts(&args);
470  if (opts == NULL)
471  return -1;
472 
473  fd = fuse_kern_mount(mountpoint, opts);
474  destroy_mount_opts(opts);
475 
476  return fd;
477 }
struct fuse_session * fuse_get_session(struct fuse *f)
Definition: fuse.c:4474
int fuse_mount(struct fuse *f, const char *mountpoint)
Definition: fuse.c:5099
void fuse_destroy(struct fuse *f)
Definition: fuse.c:5049
struct fuse * fuse_new_31(struct fuse_args *args, const struct fuse_operations *op, size_t op_size, void *user_data)
Definition: fuse.c:4872
int fuse_loop(struct fuse *f)
Definition: fuse.c:4531
void fuse_lib_help(struct fuse_args *args)
Definition: fuse.c:4694
int fuse_open_channel(const char *mountpoint, const char *options)
Definition: helper.c:461
void fuse_unmount(struct fuse *f)
Definition: fuse.c:5104
int fuse_main_real(int argc, char *argv[], const struct fuse_operations *op, size_t op_size, void *private_data)
Definition: helper.c:307
void fuse_loop_cfg_set_idle_threads(struct fuse_loop_config *config, unsigned int value)
Definition: fuse_loop_mt.c:462
#define FUSE_CAP_AUTO_INVAL_DATA
Definition: fuse_common.h:263
int fuse_set_signal_handlers(struct fuse_session *se)
Definition: fuse_signals.c:62
#define FUSE_CAP_SPLICE_READ
Definition: fuse_common.h:221
#define FUSE_CAP_WRITEBACK_CACHE
Definition: fuse_common.h:319
#define FUSE_CAP_ASYNC_READ
Definition: fuse_common.h:164
#define FUSE_CAP_SPLICE_WRITE
Definition: fuse_common.h:204
void fuse_apply_conn_info_opts(struct fuse_conn_info_opts *opts, struct fuse_conn_info *conn)
Definition: helper.c:398
#define FUSE_CAP_POSIX_LOCKS
Definition: fuse_common.h:172
struct fuse_loop_config * fuse_loop_cfg_create(void)
Definition: fuse_loop_mt.c:427
void fuse_loop_cfg_set_clone_fd(struct fuse_loop_config *config, unsigned int value)
Definition: fuse_loop_mt.c:482
#define FUSE_CAP_READDIRPLUS_AUTO
Definition: fuse_common.h:299
#define FUSE_CAP_ASYNC_DIO
Definition: fuse_common.h:310
void fuse_loop_cfg_destroy(struct fuse_loop_config *config)
Definition: fuse_loop_mt.c:441
#define FUSE_CAP_READDIRPLUS
Definition: fuse_common.h:271
void fuse_remove_signal_handlers(struct fuse_session *se)
Definition: fuse_signals.c:79
#define FUSE_CAP_SPLICE_MOVE
Definition: fuse_common.h:212
int fuse_daemonize(int foreground)
Definition: helper.c:253
void fuse_loop_cfg_set_max_threads(struct fuse_loop_config *config, unsigned int value)
Definition: fuse_loop_mt.c:476
struct fuse_conn_info_opts * fuse_parse_conn_info_opts(struct fuse_args *args)
Definition: helper.c:445
#define FUSE_CAP_FLOCK_LOCKS
Definition: fuse_common.h:234
void fuse_log(enum fuse_log_level level, const char *fmt,...)
Definition: fuse_log.c:33
void fuse_cmdline_help(void)
Definition: helper.c:130
int fuse_parse_cmdline_30(struct fuse_args *args, struct fuse_cmdline_opts *opts)
Definition: helper.c:237
void fuse_lowlevel_version(void)
int fuse_opt_add_arg(struct fuse_args *args, const char *arg)
Definition: fuse_opt.c:55
void fuse_opt_free_args(struct fuse_args *args)
Definition: fuse_opt.c:34
#define FUSE_OPT_KEY(templ, key)
Definition: fuse_opt.h:98
int fuse_opt_parse(struct fuse_args *args, void *data, const struct fuse_opt opts[], fuse_opt_proc_t proc)
Definition: fuse_opt.c:398
#define FUSE_OPT_KEY_NONOPT
Definition: fuse_opt.h:137
#define FUSE_OPT_KEY_KEEP
Definition: fuse_opt.h:145
#define FUSE_ARGS_INIT(argc, argv)
Definition: fuse_opt.h:123
int fuse_opt_add_opt(char **opts, const char *opt)
Definition: fuse_opt.c:139
#define FUSE_OPT_END
Definition: fuse_opt.h:104
int argc
Definition: fuse_opt.h:111
char ** argv
Definition: fuse_opt.h:114
unsigned time_gran
Definition: fuse_common.h:563
unsigned congestion_threshold
Definition: fuse_common.h:546
unsigned max_background
Definition: fuse_common.h:536
unsigned max_readahead
Definition: fuse_common.h:493
unsigned max_write
Definition: fuse_common.h:474