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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 "config.h"
14 #include "fuse_i.h"
15 #include "fuse_misc.h"
16 #include "fuse_opt.h"
17 #include "fuse_lowlevel.h"
18 
19 #include <stdio.h>
20 #include <stdlib.h>
21 #include <stddef.h>
22 #include <unistd.h>
23 #include <string.h>
24 #include <limits.h>
25 #include <errno.h>
26 #include <sys/param.h>
27 
28 #define FUSE_HELPER_OPT(t, p) \
29  { t, offsetof(struct fuse_cmdline_opts, p), 1 }
30 
31 static const struct fuse_opt fuse_helper_opts[] = {
32  FUSE_HELPER_OPT("-h", show_help),
33  FUSE_HELPER_OPT("--help", show_help),
34  FUSE_HELPER_OPT("-V", show_version),
35  FUSE_HELPER_OPT("--version", show_version),
36  FUSE_HELPER_OPT("-d", debug),
37  FUSE_HELPER_OPT("debug", debug),
38  FUSE_HELPER_OPT("-d", foreground),
39  FUSE_HELPER_OPT("debug", foreground),
42  FUSE_HELPER_OPT("-f", foreground),
43  FUSE_HELPER_OPT("-s", singlethread),
44  FUSE_HELPER_OPT("fsname=", nodefault_subtype),
45  FUSE_OPT_KEY("fsname=", FUSE_OPT_KEY_KEEP),
46 #ifndef __FreeBSD__
47  FUSE_HELPER_OPT("subtype=", nodefault_subtype),
48  FUSE_OPT_KEY("subtype=", FUSE_OPT_KEY_KEEP),
49 #endif
50  FUSE_HELPER_OPT("clone_fd", clone_fd),
51  FUSE_HELPER_OPT("max_idle_threads=%u", max_idle_threads),
53 };
54 
55 struct fuse_conn_info_opts {
56  int atomic_o_trunc;
57  int no_remote_posix_lock;
58  int no_remote_flock;
59  int splice_write;
60  int splice_move;
61  int splice_read;
62  int no_splice_write;
63  int no_splice_move;
64  int no_splice_read;
65  int auto_inval_data;
66  int no_auto_inval_data;
67  int no_readdirplus;
68  int no_readdirplus_auto;
69  int async_dio;
70  int no_async_dio;
71  int writeback_cache;
72  int no_writeback_cache;
73  int async_read;
74  int sync_read;
75  unsigned max_write;
76  unsigned max_readahead;
77  unsigned max_background;
78  unsigned congestion_threshold;
79  unsigned time_gran;
80  int set_max_write;
81  int set_max_readahead;
82  int set_max_background;
83  int set_congestion_threshold;
84  int set_time_gran;
85 };
86 
87 #define CONN_OPTION(t, p, v) \
88  { t, offsetof(struct fuse_conn_info_opts, p), v }
89 static const struct fuse_opt conn_info_opt_spec[] = {
90  CONN_OPTION("max_write=%u", max_write, 0),
91  CONN_OPTION("max_write=", set_max_write, 1),
92  CONN_OPTION("max_readahead=%u", max_readahead, 0),
93  CONN_OPTION("max_readahead=", set_max_readahead, 1),
94  CONN_OPTION("max_background=%u", max_background, 0),
95  CONN_OPTION("max_background=", set_max_background, 1),
96  CONN_OPTION("congestion_threshold=%u", congestion_threshold, 0),
97  CONN_OPTION("congestion_threshold=", set_congestion_threshold, 1),
98  CONN_OPTION("sync_read", sync_read, 1),
99  CONN_OPTION("async_read", async_read, 1),
100  CONN_OPTION("atomic_o_trunc", atomic_o_trunc, 1),
101  CONN_OPTION("no_remote_lock", no_remote_posix_lock, 1),
102  CONN_OPTION("no_remote_lock", no_remote_flock, 1),
103  CONN_OPTION("no_remote_flock", no_remote_flock, 1),
104  CONN_OPTION("no_remote_posix_lock", no_remote_posix_lock, 1),
105  CONN_OPTION("splice_write", splice_write, 1),
106  CONN_OPTION("no_splice_write", no_splice_write, 1),
107  CONN_OPTION("splice_move", splice_move, 1),
108  CONN_OPTION("no_splice_move", no_splice_move, 1),
109  CONN_OPTION("splice_read", splice_read, 1),
110  CONN_OPTION("no_splice_read", no_splice_read, 1),
111  CONN_OPTION("auto_inval_data", auto_inval_data, 1),
112  CONN_OPTION("no_auto_inval_data", no_auto_inval_data, 1),
113  CONN_OPTION("readdirplus=no", no_readdirplus, 1),
114  CONN_OPTION("readdirplus=yes", no_readdirplus, 0),
115  CONN_OPTION("readdirplus=yes", no_readdirplus_auto, 1),
116  CONN_OPTION("readdirplus=auto", no_readdirplus, 0),
117  CONN_OPTION("readdirplus=auto", no_readdirplus_auto, 0),
118  CONN_OPTION("async_dio", async_dio, 1),
119  CONN_OPTION("no_async_dio", no_async_dio, 1),
120  CONN_OPTION("writeback_cache", writeback_cache, 1),
121  CONN_OPTION("no_writeback_cache", no_writeback_cache, 1),
122  CONN_OPTION("time_gran=%u", time_gran, 0),
123  CONN_OPTION("time_gran=", set_time_gran, 1),
125 };
126 
127 
129 {
130  printf(" -h --help print help\n"
131  " -V --version print version\n"
132  " -d -o debug enable debug output (implies -f)\n"
133  " -f foreground operation\n"
134  " -s disable multi-threaded operation\n"
135  " -o clone_fd use separate fuse device fd for each thread\n"
136  " (may improve performance)\n"
137  " -o max_idle_threads the maximum number of idle worker threads\n"
138  " allowed (default: 10)\n");
139 }
140 
141 static int fuse_helper_opt_proc(void *data, const char *arg, int key,
142  struct fuse_args *outargs)
143 {
144  (void) outargs;
145  struct fuse_cmdline_opts *opts = data;
146 
147  switch (key) {
148  case FUSE_OPT_KEY_NONOPT:
149  if (!opts->mountpoint) {
150  char mountpoint[PATH_MAX];
151  if (realpath(arg, mountpoint) == NULL) {
152  fprintf(stderr,
153  "fuse: bad mount point `%s': %s\n",
154  arg, strerror(errno));
155  return -1;
156  }
157  return fuse_opt_add_opt(&opts->mountpoint, mountpoint);
158  } else {
159  fprintf(stderr, "fuse: invalid argument `%s'\n", arg);
160  return -1;
161  }
162 
163  default:
164  /* Pass through unknown options */
165  return 1;
166  }
167 }
168 
169 /* Under FreeBSD, there is no subtype option so this
170  function actually sets the fsname */
171 static int add_default_subtype(const char *progname, struct fuse_args *args)
172 {
173  int res;
174  char *subtype_opt;
175 
176  const char *basename = strrchr(progname, '/');
177  if (basename == NULL)
178  basename = progname;
179  else if (basename[1] != '\0')
180  basename++;
181 
182  subtype_opt = (char *) malloc(strlen(basename) + 64);
183  if (subtype_opt == NULL) {
184  fprintf(stderr, "fuse: memory allocation failed\n");
185  return -1;
186  }
187 #ifdef __FreeBSD__
188  sprintf(subtype_opt, "-ofsname=%s", basename);
189 #else
190  sprintf(subtype_opt, "-osubtype=%s", basename);
191 #endif
192  res = fuse_opt_add_arg(args, subtype_opt);
193  free(subtype_opt);
194  return res;
195 }
196 
197 int fuse_parse_cmdline(struct fuse_args *args,
198  struct fuse_cmdline_opts *opts)
199 {
200  memset(opts, 0, sizeof(struct fuse_cmdline_opts));
201 
202  opts->max_idle_threads = 10;
203 
204  if (fuse_opt_parse(args, opts, fuse_helper_opts,
205  fuse_helper_opt_proc) == -1)
206  return -1;
207 
208  /* *Linux*: if neither -o subtype nor -o fsname are specified,
209  set subtype to program's basename.
210  *FreeBSD*: if fsname is not specified, set to program's
211  basename. */
212  if (!opts->nodefault_subtype)
213  if (add_default_subtype(args->argv[0], args) == -1)
214  return -1;
215 
216  return 0;
217 }
218 
219 
220 int fuse_daemonize(int foreground)
221 {
222  if (!foreground) {
223  int nullfd;
224  int waiter[2];
225  char completed;
226 
227  if (pipe(waiter)) {
228  perror("fuse_daemonize: pipe");
229  return -1;
230  }
231 
232  /*
233  * demonize current process by forking it and killing the
234  * parent. This makes current process as a child of 'init'.
235  */
236  switch(fork()) {
237  case -1:
238  perror("fuse_daemonize: fork");
239  return -1;
240  case 0:
241  break;
242  default:
243  (void) read(waiter[0], &completed, sizeof(completed));
244  _exit(0);
245  }
246 
247  if (setsid() == -1) {
248  perror("fuse_daemonize: setsid");
249  return -1;
250  }
251 
252  (void) chdir("/");
253 
254  nullfd = open("/dev/null", O_RDWR, 0);
255  if (nullfd != -1) {
256  (void) dup2(nullfd, 0);
257  (void) dup2(nullfd, 1);
258  (void) dup2(nullfd, 2);
259  if (nullfd > 2)
260  close(nullfd);
261  }
262 
263  /* Propagate completion of daemon initialization */
264  completed = 1;
265  (void) write(waiter[1], &completed, sizeof(completed));
266  close(waiter[0]);
267  close(waiter[1]);
268  } else {
269  (void) chdir("/");
270  }
271  return 0;
272 }
273 
274 int fuse_main_real(int argc, char *argv[], const struct fuse_operations *op,
275  size_t op_size, void *user_data)
276 {
277  struct fuse_args args = FUSE_ARGS_INIT(argc, argv);
278  struct fuse *fuse;
279  struct fuse_cmdline_opts opts;
280  int res;
281 
282  if (fuse_parse_cmdline(&args, &opts) != 0)
283  return 1;
284 
285  if (opts.show_version) {
286  printf("FUSE library version %s\n", PACKAGE_VERSION);
288  res = 0;
289  goto out1;
290  }
291 
292  if (opts.show_help) {
293  if(args.argv[0][0] != '\0')
294  printf("usage: %s [options] <mountpoint>\n\n",
295  args.argv[0]);
296  printf("FUSE options:\n");
298  fuse_lib_help(&args);
299  res = 0;
300  goto out1;
301  }
302 
303  if (!opts.show_help &&
304  !opts.mountpoint) {
305  fprintf(stderr, "error: no mountpoint specified\n");
306  res = 1;
307  goto out1;
308  }
309 
310 
311  fuse = fuse_new_31(&args, op, op_size, user_data);
312  if (fuse == NULL) {
313  res = 1;
314  goto out1;
315  }
316 
317  if (fuse_mount(fuse,opts.mountpoint) != 0) {
318  res = 1;
319  goto out2;
320  }
321 
322  if (fuse_daemonize(opts.foreground) != 0) {
323  res = 1;
324  goto out3;
325  }
326 
327  struct fuse_session *se = fuse_get_session(fuse);
328  if (fuse_set_signal_handlers(se) != 0) {
329  res = 1;
330  goto out3;
331  }
332 
333  if (opts.singlethread)
334  res = fuse_loop(fuse);
335  else {
336  struct fuse_loop_config loop_config;
337  loop_config.clone_fd = opts.clone_fd;
338  loop_config.max_idle_threads = opts.max_idle_threads;
339  res = fuse_loop_mt_32(fuse, &loop_config);
340  }
341  if (res)
342  res = 1;
343 
345 out3:
346  fuse_unmount(fuse);
347 out2:
348  fuse_destroy(fuse);
349 out1:
350  free(opts.mountpoint);
351  fuse_opt_free_args(&args);
352  return res;
353 }
354 
355 
356 void fuse_apply_conn_info_opts(struct fuse_conn_info_opts *opts,
357  struct fuse_conn_info *conn)
358 {
359  if(opts->set_max_write)
360  conn->max_write = opts->max_write;
361  if(opts->set_max_background)
362  conn->max_background = opts->max_background;
363  if(opts->set_congestion_threshold)
364  conn->congestion_threshold = opts->congestion_threshold;
365  if(opts->set_time_gran)
366  conn->time_gran = opts->time_gran;
367  if(opts->set_max_readahead)
368  conn->max_readahead = opts->max_readahead;
369 
370 #define LL_ENABLE(cond,cap) \
371  if (cond) conn->want |= (cap)
372 #define LL_DISABLE(cond,cap) \
373  if (cond) conn->want &= ~(cap)
374 
375  LL_ENABLE(opts->splice_read, FUSE_CAP_SPLICE_READ);
376  LL_DISABLE(opts->no_splice_read, FUSE_CAP_SPLICE_READ);
377 
378  LL_ENABLE(opts->splice_write, FUSE_CAP_SPLICE_WRITE);
379  LL_DISABLE(opts->no_splice_write, FUSE_CAP_SPLICE_WRITE);
380 
381  LL_ENABLE(opts->splice_move, FUSE_CAP_SPLICE_MOVE);
382  LL_DISABLE(opts->no_splice_move, FUSE_CAP_SPLICE_MOVE);
383 
384  LL_ENABLE(opts->auto_inval_data, FUSE_CAP_AUTO_INVAL_DATA);
385  LL_DISABLE(opts->no_auto_inval_data, FUSE_CAP_AUTO_INVAL_DATA);
386 
387  LL_DISABLE(opts->no_readdirplus, FUSE_CAP_READDIRPLUS);
388  LL_DISABLE(opts->no_readdirplus_auto, FUSE_CAP_READDIRPLUS_AUTO);
389 
390  LL_ENABLE(opts->async_dio, FUSE_CAP_ASYNC_DIO);
391  LL_DISABLE(opts->no_async_dio, FUSE_CAP_ASYNC_DIO);
392 
393  LL_ENABLE(opts->writeback_cache, FUSE_CAP_WRITEBACK_CACHE);
394  LL_DISABLE(opts->no_writeback_cache, FUSE_CAP_WRITEBACK_CACHE);
395 
396  LL_ENABLE(opts->async_read, FUSE_CAP_ASYNC_READ);
397  LL_DISABLE(opts->sync_read, FUSE_CAP_ASYNC_READ);
398 
399  LL_DISABLE(opts->no_remote_posix_lock, FUSE_CAP_POSIX_LOCKS);
400  LL_DISABLE(opts->no_remote_flock, FUSE_CAP_FLOCK_LOCKS);
401 }
402 
403 struct fuse_conn_info_opts* fuse_parse_conn_info_opts(struct fuse_args *args)
404 {
405  struct fuse_conn_info_opts *opts;
406 
407  opts = calloc(1, sizeof(struct fuse_conn_info_opts));
408  if(opts == NULL) {
409  fprintf(stderr, "calloc failed\n");
410  return NULL;
411  }
412  if(fuse_opt_parse(args, opts, conn_info_opt_spec, NULL) == -1) {
413  free(opts);
414  return NULL;
415  }
416  return opts;
417 }
unsigned max_write
Definition: fuse_common.h:346
int fuse_daemonize(int foreground)
Definition: helper.c:220
#define FUSE_CAP_ASYNC_READ
Definition: fuse_common.h:120
unsigned int max_idle_threads
Definition: fuse_common.h:103
int fuse_loop(struct fuse *f)
Definition: fuse.c:4374
unsigned max_background
Definition: fuse_common.h:408
int fuse_opt_parse(struct fuse_args *args, void *data, const struct fuse_opt opts[], fuse_opt_proc_t proc)
Definition: fuse_opt.c:397
int fuse_parse_cmdline(struct fuse_args *args, struct fuse_cmdline_opts *opts)
Definition: helper.c:197
void fuse_cmdline_help(void)
Definition: helper.c:128
#define FUSE_CAP_READDIRPLUS_AUTO
Definition: fuse_common.h:235
int fuse_set_signal_handlers(struct fuse_session *se)
Definition: fuse_signals.c:62
#define FUSE_CAP_SPLICE_WRITE
Definition: fuse_common.h:160
void fuse_remove_signal_handlers(struct fuse_session *se)
Definition: fuse_signals.c:79
int fuse_opt_add_arg(struct fuse_args *args, const char *arg)
Definition: fuse_opt.c:54
void fuse_destroy(struct fuse *f)
Definition: fuse.c:4865
struct fuse_conn_info_opts * fuse_parse_conn_info_opts(struct fuse_args *args)
Definition: helper.c:403
void fuse_lowlevel_version(void)
void fuse_apply_conn_info_opts(struct fuse_conn_info_opts *opts, struct fuse_conn_info *conn)
Definition: helper.c:356
void fuse_opt_free_args(struct fuse_args *args)
Definition: fuse_opt.c:33
#define FUSE_CAP_SPLICE_MOVE
Definition: fuse_common.h:168
#define FUSE_CAP_AUTO_INVAL_DATA
Definition: fuse_common.h:219
#define FUSE_OPT_KEY(templ, key)
Definition: fuse_opt.h:98
#define FUSE_CAP_SPLICE_READ
Definition: fuse_common.h:177
#define FUSE_OPT_END
Definition: fuse_opt.h:104
unsigned congestion_threshold
Definition: fuse_common.h:418
struct fuse_session * fuse_get_session(struct fuse *f)
Definition: fuse.c:4317
#define FUSE_OPT_KEY_KEEP
Definition: fuse_opt.h:145
int fuse_main_real(int argc, char *argv[], const struct fuse_operations *op, size_t op_size, void *private_data)
Definition: helper.c:274
int fuse_opt_add_opt(char **opts, const char *opt)
Definition: fuse_opt.c:138
#define FUSE_CAP_FLOCK_LOCKS
Definition: fuse_common.h:190
unsigned max_readahead
Definition: fuse_common.h:365
void fuse_lib_help(struct fuse_args *args)
Definition: fuse.c:4508
#define FUSE_OPT_KEY_NONOPT
Definition: fuse_opt.h:137
char ** argv
Definition: fuse_opt.h:114
#define FUSE_CAP_ASYNC_DIO
Definition: fuse_common.h:246
#define FUSE_CAP_WRITEBACK_CACHE
Definition: fuse_common.h:255
int fuse_mount(struct fuse *f, const char *mountpoint)
Definition: fuse.c:4912
#define FUSE_CAP_POSIX_LOCKS
Definition: fuse_common.h:128
void fuse_unmount(struct fuse *f)
Definition: fuse.c:4917
#define FUSE_CAP_READDIRPLUS
Definition: fuse_common.h:227
#define FUSE_ARGS_INIT(argc, argv)
Definition: fuse_opt.h:123
unsigned time_gran
Definition: fuse_common.h:435