xref: /freebsd/sbin/mount_fusefs/mount_fusefs.c (revision b1f9167f94059fd55c630891d359bcff987bd7eb)
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 <limits.h>
48 #include <osreldate.h>
49 #include <paths.h>
50 
51 #include "mntopts.h"
52 
53 #ifndef FUSE4BSD_VERSION
54 #define	FUSE4BSD_VERSION	"0.3.9-pre1"
55 #endif
56 
57 void	__usage_short(void);
58 void	usage(void);
59 void	helpmsg(void);
60 void	showversion(void);
61 int	init_backgrounded(void);
62 
63 static struct mntopt mopts[] = {
64 	#define ALTF_PRIVATE 0x01
65 	{ "private",             0, ALTF_PRIVATE, 1 },
66 	{ "neglect_shares",      0, 0x02, 1 },
67 	{ "push_symlinks_in",    0, 0x04, 1 },
68 	{ "allow_other",         0, 0x08, 1 },
69 	{ "default_permissions", 0, 0x10, 1 },
70 	#define ALTF_MAXREAD 0x20
71 	{ "max_read=",           0, ALTF_MAXREAD, 1 },
72 	#define ALTF_SUBTYPE 0x40
73 	{ "subtype=",            0, ALTF_SUBTYPE, 1 },
74 	#define ALTF_SYNC_UNMOUNT 0x80
75 	{ "sync_unmount",        0, ALTF_SYNC_UNMOUNT, 1 },
76 	/* Linux specific options, we silently ignore them */
77 	{ "fsname=",             0, 0x00, 1 },
78 	{ "fd=",                 0, 0x00, 1 },
79 	{ "rootmode=",           0, 0x00, 1 },
80 	{ "user_id=",            0, 0x00, 1 },
81 	{ "group_id=",           0, 0x00, 1 },
82 	{ "large_read",          0, 0x00, 1 },
83 	/* "nonempty", just the first two chars are stripped off during parsing */
84 	{ "nempty",              0, 0x00, 1 },
85 	MOPT_STDOPTS,
86 	MOPT_END
87 };
88 
89 struct mntval {
90 	int mv_flag;
91 	void *mv_value;
92 	int mv_len;
93 };
94 
95 static struct mntval mvals[] = {
96 	{ ALTF_MAXREAD, NULL, 0 },
97 	{ ALTF_SUBTYPE, NULL, 0 },
98 	{ 0, NULL, 0 }
99 };
100 
101 #define DEFAULT_MOUNT_FLAGS ALTF_PRIVATE | ALTF_SYNC_UNMOUNT
102 
103 int
104 main(int argc, char *argv[])
105 {
106 	struct iovec *iov;
107 	int mntflags, iovlen, verbose = 0;
108 	char *dev = NULL, *dir = NULL, mntpath[MAXPATHLEN];
109 	char *devo = NULL, *diro = NULL;
110 	char ndev[128], fdstr[15];
111 	int i, done = 0, reject_allow_other = 0, safe_level = 0;
112 	int altflags = DEFAULT_MOUNT_FLAGS;
113 	int __altflags = DEFAULT_MOUNT_FLAGS;
114 	int ch = 0;
115 	struct mntopt *mo;
116 	struct mntval *mv;
117 	static struct option longopts[] = {
118 		{"reject-allow_other", no_argument, NULL, 'A'},
119 		{"safe", no_argument, NULL, 'S'},
120 		{"daemon", required_argument, NULL, 'D'},
121 		{"daemon_opts", required_argument, NULL, 'O'},
122 		{"special", required_argument, NULL, 's'},
123 		{"mountpath", required_argument, NULL, 'm'},
124 		{"version", no_argument, NULL, 'V'},
125 		{"help", no_argument, NULL, 'h'},
126 		{0,0,0,0}
127 	};
128 	int pid = 0;
129 	int fd = -1, fdx;
130 	char *ep;
131 	char *daemon_str = NULL, *daemon_opts = NULL;
132 
133 	/*
134 	 * We want a parsing routine which is not sensitive to
135 	 * the position of args/opts; it should extract the
136 	 * first two args and stop at the beginning of the rest.
137 	 * (This makes it easier to call mount_fusefs from external
138 	 * utils than it is with a strict "util flags args" syntax.)
139 	 */
140 
141 	iov = NULL;
142 	iovlen = 0;
143 	mntflags = 0;
144 	/* All in all, I feel it more robust this way... */
145 	unsetenv("POSIXLY_CORRECT");
146 	if (getenv("MOUNT_FUSEFS_IGNORE_UNKNOWN"))
147 		getmnt_silent = 1;
148 	if (getenv("MOUNT_FUSEFS_VERBOSE"))
149 		verbose = 1;
150 
151 	do {
152 		for (i = 0; i < 3; i++) {
153 			if (optind < argc && argv[optind][0] != '-') {
154 				if (dir) {
155 					done = 1;
156 					break;
157 				}
158 				if (dev)
159 					dir = argv[optind];
160 				else
161 					dev = argv[optind];
162 				optind++;
163 			}
164 		}
165 		switch(ch) {
166 		case 'A':
167 			reject_allow_other = 1;
168 			break;
169 		case 'S':
170 			safe_level = 1;
171 			break;
172 		case 'D':
173 			if (daemon_str)
174 				errx(1, "daemon specified inconsistently");
175 			daemon_str = optarg;
176 			break;
177 		case 'O':
178 			if (daemon_opts)
179 				errx(1, "daemon opts specified inconsistently");
180 			daemon_opts = optarg;
181 			break;
182 		case 'o':
183 			getmntopts(optarg, mopts, &mntflags, &altflags);
184 			for (mv = mvals; mv->mv_flag; ++mv) {
185 				if (! (altflags & mv->mv_flag))
186 					continue;
187 				for (mo = mopts; mo->m_flag; ++mo) {
188 					char *p, *q;
189 
190 					if (mo->m_flag != mv->mv_flag)
191 						continue;
192 					p = strstr(optarg, mo->m_option);
193 					if (p) {
194 						p += strlen(mo->m_option);
195 						q = p;
196 						while (*q != '\0' && *q != ',')
197 							q++;
198 						mv->mv_len = q - p + 1;
199 						mv->mv_value = malloc(mv->mv_len);
200 						memcpy(mv->mv_value, p, mv->mv_len - 1);
201 						((char *)mv->mv_value)[mv->mv_len - 1] = '\0';
202 						break;
203 					}
204 				}
205 			}
206 			break;
207 		case 's':
208 			if (devo)
209 				errx(1, "special specified inconsistently");
210 			devo = optarg;
211 			break;
212 		case 'm':
213 			if (diro)
214 				errx(1, "mount path specified inconsistently");
215 			diro = optarg;
216 			break;
217 		case 'v':
218 			verbose = 1;
219 			break;
220 		case 'h':
221 			helpmsg();
222 			break;
223 		case 'V':
224 			showversion();
225 			break;
226 		case '\0':
227 			break;
228 		case '?':
229 		default:
230 			usage();
231 		}
232 		if (done)
233 			break;
234 	} while ((ch = getopt_long(argc, argv, "AvVho:SD:O:s:m:", longopts, NULL)) != -1);
235 
236 	argc -= optind;
237 	argv += optind;
238 
239 	if (devo) {
240 		if (dev)
241 			errx(1, "special specified inconsistently");
242 		dev = devo;
243 	} else if (diro)
244 		errx(1, "if mountpoint is given via an option, special should also be given via an option");
245 
246 	if (diro) {
247 		if (dir)
248 			errx(1, "mount path specified inconsistently");
249 		dir = diro;
250 	}
251 
252 	if ((! dev) && argc > 0) {
253 		dev = *argv++;
254 		argc--;
255 	}
256 
257 	if ((! dir) && argc > 0) {
258 		dir = *argv++;
259 		argc--;
260 	}
261 
262 	if (! (dev && dir))
263 		errx(1, "missing special and/or mountpoint");
264 
265 	for (mo = mopts; mo->m_flag; ++mo) {
266 		if (altflags & mo->m_flag) {
267 			int iov_done = 0;
268 
269 			if (reject_allow_other &&
270 			    strcmp(mo->m_option, "allow_other") == 0)
271 				/*
272 				 * reject_allow_other is stronger than a
273 				 * negative of allow_other: if this is set,
274 				 * allow_other is blocked, period.
275 				 */
276 				errx(1, "\"allow_other\" usage is banned by respective option");
277 
278 			for (mv = mvals; mv->mv_flag; ++mv) {
279 				if (mo->m_flag != mv->mv_flag)
280 					continue;
281 				if (mv->mv_value) {
282 					build_iovec(&iov, &iovlen, mo->m_option, mv->mv_value, mv->mv_len);
283 					iov_done = 1;
284 					break;
285 				}
286 			}
287 			if (! iov_done)
288 				build_iovec(&iov, &iovlen, mo->m_option,
289 				    __DECONST(void *, ""), -1);
290 		}
291 		if (__altflags & mo->m_flag) {
292 			char *uscore_opt;
293 
294 			if (asprintf(&uscore_opt, "__%s", mo->m_option) == -1)
295 				err(1, "failed to allocate memory");
296 			build_iovec(&iov, &iovlen, uscore_opt,
297 			    __DECONST(void *, ""), -1);
298 			free(uscore_opt);
299 		}
300 	}
301 
302 	if (getenv("MOUNT_FUSEFS_SAFE"))
303 		safe_level = 1;
304 
305 	if (safe_level > 0 && (argc > 0 || daemon_str || daemon_opts))
306 		errx(1, "safe mode, spawning daemon not allowed");
307 
308 	if ((argc > 0 && (daemon_str || daemon_opts)) ||
309 	    (daemon_opts && ! daemon_str))
310 		errx(1, "daemon specified inconsistently");
311 
312 	/*
313 	 * Resolve the mountpoint with realpath(3) and remove unnecessary
314 	 * slashes from the devicename if there are any.
315 	 */
316 	if (checkpath(dir, mntpath) != 0)
317 		err(1, "%s", mntpath);
318 	(void)rmslashes(dev, dev);
319 
320 	if (strcmp(dev, "auto") == 0)
321 		dev = __DECONST(char *, "/dev/fuse");
322 
323 	if (strcmp(dev, "/dev/fuse") == 0) {
324 		if (! (argc > 0 || daemon_str)) {
325 			fprintf(stderr, "Please also specify the fuse daemon to run when mounting via the multiplexer!\n");
326 			usage();
327 		}
328 		if ((fd = open(dev, O_RDWR)) < 0)
329 			err(1, "failed to open fuse device");
330 	} else {
331 		fdx = strtol(dev, &ep, 10);
332 		if (*ep == '\0')
333 			fd = fdx;
334 	}
335 
336 	/* Identifying device */
337 	if (fd >= 0) {
338 		struct stat sbuf;
339 		char *ndevbas, *lep;
340 
341 		if (fstat(fd, &sbuf) == -1)
342 			err(1, "cannot stat device file descriptor");
343 
344 		strcpy(ndev, _PATH_DEV);
345 		ndevbas = ndev + strlen(_PATH_DEV);
346 		devname_r(sbuf.st_rdev, S_IFCHR, ndevbas,
347 		          sizeof(ndev) - strlen(_PATH_DEV));
348 
349 		if (strncmp(ndevbas, "fuse", 4))
350 			errx(1, "mounting inappropriate device");
351 
352 		strtol(ndevbas + 4, &lep, 10);
353 		if (*lep != '\0')
354 			errx(1, "mounting inappropriate device");
355 
356 		dev = ndev;
357 	}
358 
359 	if (argc > 0 || daemon_str) {
360 		char *fds;
361 
362 		if (fd < 0 && (fd = open(dev, O_RDWR)) < 0)
363 			err(1, "failed to open fuse device");
364 
365 		if (asprintf(&fds, "%d", fd) == -1)
366 			err(1, "failed to allocate memory");
367 		setenv("FUSE_DEV_FD", fds, 1);
368 		free(fds);
369 		setenv("FUSE_NO_MOUNT", "1", 1);
370 
371 		if (daemon_str) {
372 			char *bgdaemon;
373 			int len;
374 
375 			if (! daemon_opts)
376 				daemon_opts = __DECONST(char *, "");
377 
378 			len =  strlen(daemon_str) + 1 + strlen(daemon_opts) +
379 			    2 + 1;
380 			bgdaemon = calloc(1, len);
381 
382 			if (! bgdaemon)
383 				err(1, "failed to allocate memory");
384 
385 			strlcpy(bgdaemon, daemon_str, len);
386 			strlcat(bgdaemon, " ", len);
387 			strlcat(bgdaemon, daemon_opts, len);
388 			strlcat(bgdaemon, " &", len);
389 
390 			if (system(bgdaemon))
391 				err(1, "failed to call fuse daemon");
392 		} else {
393 			if ((pid = fork()) < 0)
394 				err(1, "failed to fork for fuse daemon");
395 
396 			if (pid == 0) {
397 				execvp(argv[0], argv);
398 				err(1, "failed to exec fuse daemon");
399 			}
400 		}
401 	}
402 
403 	if (fd >= 0 && ! init_backgrounded() && close(fd) < 0) {
404 		if (pid)
405 			kill(pid, SIGKILL);
406 		err(1, "failed to close fuse device");
407 	}
408 
409 	/* Prepare the options vector for nmount(). build_iovec() is declared
410 	 * in mntopts.h. */
411 	sprintf(fdstr, "%d", fd);
412 	build_iovec(&iov, &iovlen, "fstype", __DECONST(void *, "fusefs"), -1);
413 	build_iovec(&iov, &iovlen, "fspath", mntpath, -1);
414 	build_iovec(&iov, &iovlen, "from", dev, -1);
415 	build_iovec(&iov, &iovlen, "fd", fdstr, -1);
416 
417 	if (verbose)
418 		fprintf(stderr, "mounting fuse daemon on device %s\n", dev);
419 
420 	if (nmount(iov, iovlen, mntflags) < 0)
421 		err(EX_OSERR, "%s on %s", dev, mntpath);
422 
423 	exit(0);
424 }
425 
426 void
427 __usage_short(void) {
428 	fprintf(stderr,
429 	    "usage:\n%s [-A|-S|-v|-V|-h|-D daemon|-O args|-s special|-m node|-o option...] special node [daemon args...]\n\n",
430 	    getprogname());
431 }
432 
433 void
434 usage(void)
435 {
436 	struct mntopt *mo;
437 
438 	__usage_short();
439 
440 	fprintf(stderr, "known options:\n");
441 	for (mo = mopts; mo->m_flag; ++mo)
442 		fprintf(stderr, "\t%s\n", mo->m_option);
443 
444 	fprintf(stderr, "\n(use -h for a detailed description of these options)\n");
445 	exit(EX_USAGE);
446 }
447 
448 void
449 helpmsg(void)
450 {
451 	if (! getenv("MOUNT_FUSEFS_CALL_BY_LIB")) {
452 		__usage_short();
453 		fprintf(stderr, "description of options:\n");
454 	}
455 
456 	/*
457 	 * The main use case of this function is giving info embedded in general
458 	 * FUSE lib help output. Therefore the style and the content of the output
459 	 * tries to fit there as much as possible.
460 	 */
461 	fprintf(stderr,
462 	        "    -o allow_other         allow access to other users\n"
463 	        /* "    -o nonempty            allow mounts over non-empty file/dir\n" */
464 	        "    -o default_permissions enable permission checking by kernel\n"
465 		/*
466 	        "    -o fsname=NAME         set filesystem name\n"
467 	        "    -o large_read          issue large read requests (2.4 only)\n"
468 		 */
469 	        "    -o subtype=NAME        set filesystem type\n"
470 	        "    -o max_read=N          set maximum size of read requests\n"
471 	        "    -o noprivate           allow secondary mounting of the filesystem\n"
472 	        "    -o neglect_shares      don't report EBUSY when unmount attempted\n"
473 	        "                           in presence of secondary mounts\n"
474 	        "    -o push_symlinks_in    prefix absolute symlinks with mountpoint\n"
475 	        "    -o sync_unmount        do unmount synchronously\n"
476 	        );
477 	exit(EX_USAGE);
478 }
479 
480 void
481 showversion(void)
482 {
483 	puts("mount_fusefs [fuse4bsd] version: " FUSE4BSD_VERSION);
484 	exit(EX_USAGE);
485 }
486 
487 int
488 init_backgrounded(void)
489 {
490 	int ibg;
491 	size_t len;
492 
493 	len = sizeof(ibg);
494 
495 	if (sysctlbyname("vfs.fuse.init_backgrounded", &ibg, &len, NULL, 0))
496 		return (0);
497 
498 	return (ibg);
499 }
500