xref: /freebsd/sbin/mount_fusefs/mount_fusefs.c (revision 9a41df2a0e6408e9b329bbd8b9e37c2b44461a1b)
1 /*-
2  * Copyright (c) 2005 Jean-Sebastien Pedron
3  * Copyright (c) 2005 Csaba Henk
4  * All rights reserved.
5  *
6  * Redistribution and use in source and binary forms, with or without
7  * modification, are permitted provided that the following conditions
8  * are met:
9  * 1. Redistributions of source code must retain the above copyright
10  *    notice, this list of conditions and the following disclaimer.
11  * 2. Redistributions in binary form must reproduce the above copyright
12  *    notice, this list of conditions and the following disclaimer in the
13  *    documentation and/or other materials provided with the distribution.
14  *
15  * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
16  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
17  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
18  * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
19  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
20  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
21  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
22  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
23  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
24  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
25  * SUCH DAMAGE.
26  *
27  */
28 
29 #include <sys/cdefs.h>
30 __FBSDID("$FreeBSD$");
31 
32 #include <sys/param.h>
33 #include <sys/mount.h>
34 #include <sys/uio.h>
35 #include <sys/stat.h>
36 #include <sys/sysctl.h>
37 
38 #include <err.h>
39 #include <stdio.h>
40 #include <stdlib.h>
41 #include <string.h>
42 #include <sysexits.h>
43 #include <unistd.h>
44 #include <fcntl.h>
45 #include <signal.h>
46 #include <getopt.h>
47 #include <libgen.h>
48 #include <limits.h>
49 #include <osreldate.h>
50 #include <paths.h>
51 
52 #include "mntopts.h"
53 
54 #ifndef FUSE4BSD_VERSION
55 #define	FUSE4BSD_VERSION	"0.3.9-pre1"
56 #endif
57 
58 void	__usage_short(void);
59 void	usage(void);
60 void	helpmsg(void);
61 void	showversion(void);
62 int	init_backgrounded(void);
63 
64 struct mntopt mopts[] = {
65 	#define ALTF_PRIVATE 0x01
66 	{ "private",             0, ALTF_PRIVATE, 1 },
67 	{ "neglect_shares",      0, 0x02, 1 },
68 	{ "push_symlinks_in",    0, 0x04, 1 },
69 	{ "allow_other",         0, 0x08, 1 },
70 	{ "default_permissions", 0, 0x10, 1 },
71 	#define ALTF_MAXREAD 0x20
72 	{ "max_read=",           0, ALTF_MAXREAD, 1 },
73 	#define ALTF_SUBTYPE 0x40
74 	{ "subtype=",            0, ALTF_SUBTYPE, 1 },
75 	#define ALTF_SYNC_UNMOUNT 0x80
76 	{ "sync_unmount",        0, ALTF_SYNC_UNMOUNT, 1 },
77 	/* Linux specific options, we silently ignore them */
78 	{ "fsname=",             0, 0x00, 1 },
79 	{ "fd=",                 0, 0x00, 1 },
80 	{ "rootmode=",           0, 0x00, 1 },
81 	{ "user_id=",            0, 0x00, 1 },
82 	{ "group_id=",           0, 0x00, 1 },
83 	{ "large_read",          0, 0x00, 1 },
84 	/* "nonempty", just the first two chars are stripped off during parsing */
85 	{ "nempty",              0, 0x00, 1 },
86 	MOPT_STDOPTS,
87 	MOPT_END
88 };
89 
90 struct mntval {
91 	int mv_flag;
92 	void *mv_value;
93 	int mv_len;
94 };
95 
96 struct mntval mvals[] = {
97 	{ ALTF_MAXREAD, NULL, 0 },
98 	{ ALTF_SUBTYPE, NULL, 0 },
99 	{ 0, NULL, 0 }
100 };
101 
102 char *progname;
103 
104 #define DEFAULT_MOUNT_FLAGS ALTF_PRIVATE | ALTF_SYNC_UNMOUNT
105 
106 int
107 main(int argc, char *argv[])
108 {
109 	struct iovec *iov;
110 	int mntflags, iovlen, verbose = 0;
111 	char *dev = NULL, *dir = NULL, mntpath[MAXPATHLEN];
112 	char *devo = NULL, *diro = NULL;
113 	char ndev[128], fdstr[15];
114 	int i, done = 0, reject_allow_other = 0, safe_level = 0;
115 	int altflags = DEFAULT_MOUNT_FLAGS;
116 	int __altflags = DEFAULT_MOUNT_FLAGS;
117 	int ch = 0;
118 	struct mntopt *mo;
119 	struct mntval *mv;
120 	static struct option longopts[] = {
121 		{"reject-allow_other", no_argument, NULL, 'A'},
122 		{"safe", no_argument, NULL, 'S'},
123 		{"daemon", required_argument, NULL, 'D'},
124 		{"daemon_opts", required_argument, NULL, 'O'},
125 		{"special", required_argument, NULL, 's'},
126 		{"mountpath", required_argument, NULL, 'm'},
127 		{"version", no_argument, NULL, 'V'},
128 		{"help", no_argument, NULL, 'h'},
129 		{0,0,0,0}
130 	};
131 	int pid = 0;
132 	int fd = -1, fdx;
133 	char *ep;
134 	char *daemon_str = NULL, *daemon_opts = NULL;
135 
136 	progname = argv[0];
137 
138 	/*
139 	 * We want a parsing routine which is not sensitive to
140 	 * the position of args/opts; it should extract the
141 	 * first two args and stop at the beginning of the rest.
142 	 * (This makes it easier to call mount_fusefs from external
143 	 * utils than it is with a strict "util flags args" syntax.)
144 	 */
145 
146 	iov = NULL;
147 	iovlen = 0;
148 	mntflags = 0;
149 	/* All in all, I feel it more robust this way... */
150 	unsetenv("POSIXLY_CORRECT");
151 	if (getenv("MOUNT_FUSEFS_IGNORE_UNKNOWN"))
152 		getmnt_silent = 1;
153 	if (getenv("MOUNT_FUSEFS_VERBOSE"))
154 		verbose = 1;
155 
156 	do {
157 		for (i = 0; i < 3; i++) {
158 			if (optind < argc && argv[optind][0] != '-') {
159 				if (dir) {
160 					done = 1;
161 					break;
162 				}
163 				if (dev)
164 					dir = argv[optind];
165 				else
166 					dev = argv[optind];
167 				optind++;
168 			}
169 		}
170 		switch(ch) {
171 		case 'A':
172 			reject_allow_other = 1;
173 			break;
174 		case 'S':
175 			safe_level = 1;
176 			break;
177 		case 'D':
178 			if (daemon_str)
179 				errx(1, "daemon specified inconsistently");
180 			daemon_str = optarg;
181 			break;
182 		case 'O':
183 			if (daemon_opts)
184 				errx(1, "daemon opts specified inconsistently");
185 			daemon_opts = optarg;
186 			break;
187 		case 'o':
188 			getmntopts(optarg, mopts, &mntflags, &altflags);
189 			for (mv = mvals; mv->mv_flag; ++mv) {
190 				if (! (altflags & mv->mv_flag))
191 					continue;
192 				for (mo = mopts; mo->m_flag; ++mo) {
193 					char *p, *q;
194 
195 					if (mo->m_flag != mv->mv_flag)
196 						continue;
197 					p = strstr(optarg, mo->m_option);
198 					if (p) {
199 						p += strlen(mo->m_option);
200 						q = p;
201 						while (*q != '\0' && *q != ',')
202 							q++;
203 						mv->mv_len = q - p + 1;
204 						mv->mv_value = malloc(mv->mv_len);
205 						memcpy(mv->mv_value, p, mv->mv_len - 1);
206 						((char *)mv->mv_value)[mv->mv_len - 1] = '\0';
207 						break;
208 					}
209 				}
210 			}
211 			break;
212 		case 's':
213 			if (devo)
214 				errx(1, "special specified inconsistently");
215 			devo = optarg;
216 			break;
217 		case 'm':
218 			if (diro)
219 				errx(1, "mount path specified inconsistently");
220 			diro = optarg;
221 			break;
222 		case 'v':
223 			verbose = 1;
224 			break;
225 		case 'h':
226 			helpmsg();
227 			break;
228 		case 'V':
229 			showversion();
230 			break;
231 		case '\0':
232 			break;
233 		case '?':
234 		default:
235 			usage();
236 		}
237 		if (done)
238 			break;
239 	} while ((ch = getopt_long(argc, argv, "AvVho:SD:O:s:m:", longopts, NULL)) != -1);
240 
241 	argc -= optind;
242 	argv += optind;
243 
244 	if (devo) {
245 		if (dev)
246 			errx(1, "special specified inconsistently");
247 		dev = devo;
248 	} else if (diro)
249 		errx(1, "if mountpoint is given via an option, special should also be given via an option");
250 
251 	if (diro) {
252 		if (dir)
253 			errx(1, "mount path specified inconsistently");
254 		dir = diro;
255 	}
256 
257 	if ((! dev) && argc > 0) {
258 		dev = *argv++;
259 		argc--;
260 	}
261 
262 	if ((! dir) && argc > 0) {
263 		dir = *argv++;
264 		argc--;
265 	}
266 
267 	if (! (dev && dir))
268 		errx(1, "missing special and/or mountpoint");
269 
270 	for (mo = mopts; mo->m_flag; ++mo) {
271 		if (altflags & mo->m_flag) {
272 			int iov_done = 0;
273 
274 			if (reject_allow_other &&
275 			    strcmp(mo->m_option, "allow_other") == 0)
276 				/*
277 				 * reject_allow_other is stronger than a
278 				 * negative of allow_other: if this is set,
279 				 * allow_other is blocked, period.
280 				 */
281 				errx(1, "\"allow_other\" usage is banned by respective option");
282 
283 			for (mv = mvals; mv->mv_flag; ++mv) {
284 				if (mo->m_flag != mv->mv_flag)
285 					continue;
286 				if (mv->mv_value) {
287 					build_iovec(&iov, &iovlen, mo->m_option, mv->mv_value, mv->mv_len);
288 					iov_done = 1;
289 					break;
290 				}
291 			}
292 			if (! iov_done)
293 				build_iovec(&iov, &iovlen, mo->m_option,
294 				    __DECONST(void *, ""), -1);
295 		}
296 		if (__altflags & mo->m_flag) {
297 			char *uscore_opt;
298 
299 			if (asprintf(&uscore_opt, "__%s", mo->m_option) == -1)
300 				err(1, "failed to allocate memory");
301 			build_iovec(&iov, &iovlen, uscore_opt,
302 			    __DECONST(void *, ""), -1);
303 			free(uscore_opt);
304 		}
305 	}
306 
307 	if (getenv("MOUNT_FUSEFS_SAFE"))
308 		safe_level = 1;
309 
310 	if (safe_level > 0 && (argc > 0 || daemon_str || daemon_opts))
311 		errx(1, "safe mode, spawning daemon not allowed");
312 
313 	if ((argc > 0 && (daemon_str || daemon_opts)) ||
314 	    (daemon_opts && ! daemon_str))
315 		errx(1, "daemon specified inconsistently");
316 
317 	/*
318 	 * Resolve the mountpoint with realpath(3) and remove unnecessary
319 	 * slashes from the devicename if there are any.
320 	 */
321 	if (checkpath(dir, mntpath) != 0)
322 		err(1, "%s", mntpath);
323 	(void)rmslashes(dev, dev);
324 
325 	if (strcmp(dev, "auto") == 0)
326 		dev = __DECONST(char *, "/dev/fuse");
327 
328 	if (strcmp(dev, "/dev/fuse") == 0) {
329 		if (! (argc > 0 || daemon_str)) {
330 			fprintf(stderr, "Please also specify the fuse daemon to run when mounting via the multiplexer!\n");
331 			usage();
332 		}
333 		if ((fd = open(dev, O_RDWR)) < 0)
334 			err(1, "failed to open fuse device");
335 	} else {
336 		fdx = strtol(dev, &ep, 10);
337 		if (*ep == '\0')
338 			fd = fdx;
339 	}
340 
341 	/* Identifying device */
342 	if (fd >= 0) {
343 		struct stat sbuf;
344 		char *ndevbas, *lep;
345 
346 		if (fstat(fd, &sbuf) == -1)
347 			err(1, "cannot stat device file descriptor");
348 
349 		strcpy(ndev, _PATH_DEV);
350 		ndevbas = ndev + strlen(_PATH_DEV);
351 		devname_r(sbuf.st_rdev, S_IFCHR, ndevbas,
352 		          sizeof(ndev) - strlen(_PATH_DEV));
353 
354 		if (strncmp(ndevbas, "fuse", 4))
355 			errx(1, "mounting inappropriate device");
356 
357 		strtol(ndevbas + 4, &lep, 10);
358 		if (*lep != '\0')
359 			errx(1, "mounting inappropriate device");
360 
361 		dev = ndev;
362 	}
363 
364 	if (argc > 0 || daemon_str) {
365 		char *fds;
366 
367 		if (fd < 0 && (fd = open(dev, O_RDWR)) < 0)
368 			err(1, "failed to open fuse device");
369 
370 		if (asprintf(&fds, "%d", fd) == -1)
371 			err(1, "failed to allocate memory");
372 		setenv("FUSE_DEV_FD", fds, 1);
373 		free(fds);
374 		setenv("FUSE_NO_MOUNT", "1", 1);
375 
376 		if (daemon_str) {
377 			char *bgdaemon;
378 			int len;
379 
380 			if (! daemon_opts)
381 				daemon_opts = __DECONST(char *, "");
382 
383 			len =  strlen(daemon_str) + 1 + strlen(daemon_opts) +
384 			    2 + 1;
385 			bgdaemon = calloc(1, len);
386 
387 			if (! bgdaemon)
388 				err(1, "failed to allocate memory");
389 
390 			strlcpy(bgdaemon, daemon_str, len);
391 			strlcat(bgdaemon, " ", len);
392 			strlcat(bgdaemon, daemon_opts, len);
393 			strlcat(bgdaemon, " &", len);
394 
395 			if (system(bgdaemon))
396 				err(1, "failed to call fuse daemon");
397 		} else {
398 			if ((pid = fork()) < 0)
399 				err(1, "failed to fork for fuse daemon");
400 
401 			if (pid == 0) {
402 				execvp(argv[0], argv);
403 				err(1, "failed to exec fuse daemon");
404 			}
405 		}
406 	}
407 
408 	if (fd >= 0 && ! init_backgrounded() && close(fd) < 0) {
409 		if (pid)
410 			kill(pid, SIGKILL);
411 		err(1, "failed to close fuse device");
412 	}
413 
414 	/* Prepare the options vector for nmount(). build_iovec() is declared
415 	 * in mntopts.h. */
416 	sprintf(fdstr, "%d", fd);
417 	build_iovec(&iov, &iovlen, "fstype", __DECONST(void *, "fusefs"), -1);
418 	build_iovec(&iov, &iovlen, "fspath", mntpath, -1);
419 	build_iovec(&iov, &iovlen, "from", dev, -1);
420 	build_iovec(&iov, &iovlen, "fd", fdstr, -1);
421 
422 	if (verbose)
423 		fprintf(stderr, "mounting fuse daemon on device %s\n", dev);
424 
425 	if (nmount(iov, iovlen, mntflags) < 0)
426 		err(EX_OSERR, "%s on %s", dev, mntpath);
427 
428 	exit(0);
429 }
430 
431 void
432 __usage_short(void) {
433 	fprintf(stderr,
434 	    "usage:\n%s [-A|-S|-v|-V|-h|-D daemon|-O args|-s special|-m node|-o option...] special node [daemon args...]\n\n",
435 	    basename(progname));
436 }
437 
438 void
439 usage(void)
440 {
441 	struct mntopt *mo;
442 
443 	__usage_short();
444 
445 	fprintf(stderr, "known options:\n");
446 	for (mo = mopts; mo->m_flag; ++mo)
447 		fprintf(stderr, "\t%s\n", mo->m_option);
448 
449 	fprintf(stderr, "\n(use -h for a detailed description of these options)\n");
450 	exit(EX_USAGE);
451 }
452 
453 void
454 helpmsg(void)
455 {
456 	if (! getenv("MOUNT_FUSEFS_CALL_BY_LIB")) {
457 		__usage_short();
458 		fprintf(stderr, "description of options:\n");
459 	}
460 
461 	/*
462 	 * The main use case of this function is giving info embedded in general
463 	 * FUSE lib help output. Therefore the style and the content of the output
464 	 * tries to fit there as much as possible.
465 	 */
466 	fprintf(stderr,
467 	        "    -o allow_other         allow access to other users\n"
468 	        /* "    -o nonempty            allow mounts over non-empty file/dir\n" */
469 	        "    -o default_permissions enable permission checking by kernel\n"
470 		/*
471 	        "    -o fsname=NAME         set filesystem name\n"
472 	        "    -o large_read          issue large read requests (2.4 only)\n"
473 		 */
474 	        "    -o subtype=NAME        set filesystem type\n"
475 	        "    -o max_read=N          set maximum size of read requests\n"
476 	        "    -o noprivate           allow secondary mounting of the filesystem\n"
477 	        "    -o neglect_shares      don't report EBUSY when unmount attempted\n"
478 	        "                           in presence of secondary mounts\n"
479 	        "    -o push_symlinks_in    prefix absolute symlinks with mountpoint\n"
480 	        "    -o sync_unmount        do unmount synchronously\n"
481 	        );
482 	exit(EX_USAGE);
483 }
484 
485 void
486 showversion(void)
487 {
488 	puts("mount_fusefs [fuse4bsd] version: " FUSE4BSD_VERSION);
489 	exit(EX_USAGE);
490 }
491 
492 int
493 init_backgrounded(void)
494 {
495 	int ibg;
496 	size_t len;
497 
498 	len = sizeof(ibg);
499 
500 	if (sysctlbyname("vfs.fuse.init_backgrounded", &ibg, &len, NULL, 0))
501 		return (0);
502 
503 	return (ibg);
504 }
505