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: releng/10.3/sbin/mount_fusefs/mount_fusefs.c 282959 2015-05-15 11:00:12Z trasz $");
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
57void	__usage_short(void);
58void	usage(void);
59void	helpmsg(void);
60void	showversion(void);
61int	init_backgrounded(void);
62
63static 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	/*
77	 * MOPT_AUTOMOUNTED, included by MOPT_STDOPTS, does not fit into
78	 * the 'flags' argument to nmount(2).  We have to abuse altflags
79	 * to pass it, as string, via iovec.
80	 */
81	#define ALTF_AUTOMOUNTED 0x100
82	{ "automounted",	0, ALTF_AUTOMOUNTED, 1 },
83	/* Linux specific options, we silently ignore them */
84	{ "fsname=",             0, 0x00, 1 },
85	{ "fd=",                 0, 0x00, 1 },
86	{ "rootmode=",           0, 0x00, 1 },
87	{ "user_id=",            0, 0x00, 1 },
88	{ "group_id=",           0, 0x00, 1 },
89	{ "large_read",          0, 0x00, 1 },
90	/* "nonempty", just the first two chars are stripped off during parsing */
91	{ "nempty",              0, 0x00, 1 },
92	MOPT_STDOPTS,
93	MOPT_END
94};
95
96struct mntval {
97	int mv_flag;
98	void *mv_value;
99	int mv_len;
100};
101
102static struct mntval mvals[] = {
103	{ ALTF_MAXREAD, NULL, 0 },
104	{ ALTF_SUBTYPE, NULL, 0 },
105	{ 0, NULL, 0 }
106};
107
108#define DEFAULT_MOUNT_FLAGS ALTF_PRIVATE | ALTF_SYNC_UNMOUNT
109
110int
111main(int argc, char *argv[])
112{
113	struct iovec *iov;
114	int mntflags, iovlen, verbose = 0;
115	char *dev = NULL, *dir = NULL, mntpath[MAXPATHLEN];
116	char *devo = NULL, *diro = NULL;
117	char ndev[128], fdstr[15];
118	int i, done = 0, reject_allow_other = 0, safe_level = 0;
119	int altflags = DEFAULT_MOUNT_FLAGS;
120	int __altflags = DEFAULT_MOUNT_FLAGS;
121	int ch = 0;
122	struct mntopt *mo;
123	struct mntval *mv;
124	static struct option longopts[] = {
125		{"reject-allow_other", no_argument, NULL, 'A'},
126		{"safe", no_argument, NULL, 'S'},
127		{"daemon", required_argument, NULL, 'D'},
128		{"daemon_opts", required_argument, NULL, 'O'},
129		{"special", required_argument, NULL, 's'},
130		{"mountpath", required_argument, NULL, 'm'},
131		{"version", no_argument, NULL, 'V'},
132		{"help", no_argument, NULL, 'h'},
133		{0,0,0,0}
134	};
135	int pid = 0;
136	int fd = -1, fdx;
137	char *ep;
138	char *daemon_str = NULL, *daemon_opts = NULL;
139
140	/*
141	 * We want a parsing routine which is not sensitive to
142	 * the position of args/opts; it should extract the
143	 * first two args and stop at the beginning of the rest.
144	 * (This makes it easier to call mount_fusefs from external
145	 * utils than it is with a strict "util flags args" syntax.)
146	 */
147
148	iov = NULL;
149	iovlen = 0;
150	mntflags = 0;
151	/* All in all, I feel it more robust this way... */
152	unsetenv("POSIXLY_CORRECT");
153	if (getenv("MOUNT_FUSEFS_IGNORE_UNKNOWN"))
154		getmnt_silent = 1;
155	if (getenv("MOUNT_FUSEFS_VERBOSE"))
156		verbose = 1;
157
158	do {
159		for (i = 0; i < 3; i++) {
160			if (optind < argc && argv[optind][0] != '-') {
161				if (dir) {
162					done = 1;
163					break;
164				}
165				if (dev)
166					dir = argv[optind];
167				else
168					dev = argv[optind];
169				optind++;
170			}
171		}
172		switch(ch) {
173		case 'A':
174			reject_allow_other = 1;
175			break;
176		case 'S':
177			safe_level = 1;
178			break;
179		case 'D':
180			if (daemon_str)
181				errx(1, "daemon specified inconsistently");
182			daemon_str = optarg;
183			break;
184		case 'O':
185			if (daemon_opts)
186				errx(1, "daemon opts specified inconsistently");
187			daemon_opts = optarg;
188			break;
189		case 'o':
190			getmntopts(optarg, mopts, &mntflags, &altflags);
191			for (mv = mvals; mv->mv_flag; ++mv) {
192				if (! (altflags & mv->mv_flag))
193					continue;
194				for (mo = mopts; mo->m_flag; ++mo) {
195					char *p, *q;
196
197					if (mo->m_flag != mv->mv_flag)
198						continue;
199					p = strstr(optarg, mo->m_option);
200					if (p) {
201						p += strlen(mo->m_option);
202						q = p;
203						while (*q != '\0' && *q != ',')
204							q++;
205						mv->mv_len = q - p + 1;
206						mv->mv_value = malloc(mv->mv_len);
207						memcpy(mv->mv_value, p, mv->mv_len - 1);
208						((char *)mv->mv_value)[mv->mv_len - 1] = '\0';
209						break;
210					}
211				}
212			}
213			break;
214		case 's':
215			if (devo)
216				errx(1, "special specified inconsistently");
217			devo = optarg;
218			break;
219		case 'm':
220			if (diro)
221				errx(1, "mount path specified inconsistently");
222			diro = optarg;
223			break;
224		case 'v':
225			verbose = 1;
226			break;
227		case 'h':
228			helpmsg();
229			break;
230		case 'V':
231			showversion();
232			break;
233		case '\0':
234			break;
235		case '?':
236		default:
237			usage();
238		}
239		if (done)
240			break;
241	} while ((ch = getopt_long(argc, argv, "AvVho:SD:O:s:m:", longopts, NULL)) != -1);
242
243	argc -= optind;
244	argv += optind;
245
246	if (devo) {
247		if (dev)
248			errx(1, "special specified inconsistently");
249		dev = devo;
250	} else if (diro)
251		errx(1, "if mountpoint is given via an option, special should also be given via an option");
252
253	if (diro) {
254		if (dir)
255			errx(1, "mount path specified inconsistently");
256		dir = diro;
257	}
258
259	if ((! dev) && argc > 0) {
260		dev = *argv++;
261		argc--;
262	}
263
264	if ((! dir) && argc > 0) {
265		dir = *argv++;
266		argc--;
267	}
268
269	if (! (dev && dir))
270		errx(1, "missing special and/or mountpoint");
271
272	for (mo = mopts; mo->m_flag; ++mo) {
273		if (altflags & mo->m_flag) {
274			int iov_done = 0;
275
276			if (reject_allow_other &&
277			    strcmp(mo->m_option, "allow_other") == 0)
278				/*
279				 * reject_allow_other is stronger than a
280				 * negative of allow_other: if this is set,
281				 * allow_other is blocked, period.
282				 */
283				errx(1, "\"allow_other\" usage is banned by respective option");
284
285			for (mv = mvals; mv->mv_flag; ++mv) {
286				if (mo->m_flag != mv->mv_flag)
287					continue;
288				if (mv->mv_value) {
289					build_iovec(&iov, &iovlen, mo->m_option, mv->mv_value, mv->mv_len);
290					iov_done = 1;
291					break;
292				}
293			}
294			if (! iov_done)
295				build_iovec(&iov, &iovlen, mo->m_option,
296				    __DECONST(void *, ""), -1);
297		}
298		if (__altflags & mo->m_flag) {
299			char *uscore_opt;
300
301			if (asprintf(&uscore_opt, "__%s", mo->m_option) == -1)
302				err(1, "failed to allocate memory");
303			build_iovec(&iov, &iovlen, uscore_opt,
304			    __DECONST(void *, ""), -1);
305			free(uscore_opt);
306		}
307	}
308
309	if (getenv("MOUNT_FUSEFS_SAFE"))
310		safe_level = 1;
311
312	if (safe_level > 0 && (argc > 0 || daemon_str || daemon_opts))
313		errx(1, "safe mode, spawning daemon not allowed");
314
315	if ((argc > 0 && (daemon_str || daemon_opts)) ||
316	    (daemon_opts && ! daemon_str))
317		errx(1, "daemon specified inconsistently");
318
319	/*
320	 * Resolve the mountpoint with realpath(3) and remove unnecessary
321	 * slashes from the devicename if there are any.
322	 */
323	if (checkpath(dir, mntpath) != 0)
324		err(1, "%s", mntpath);
325	(void)rmslashes(dev, dev);
326
327	if (strcmp(dev, "auto") == 0)
328		dev = __DECONST(char *, "/dev/fuse");
329
330	if (strcmp(dev, "/dev/fuse") == 0) {
331		if (! (argc > 0 || daemon_str)) {
332			fprintf(stderr, "Please also specify the fuse daemon to run when mounting via the multiplexer!\n");
333			usage();
334		}
335		if ((fd = open(dev, O_RDWR)) < 0)
336			err(1, "failed to open fuse device");
337	} else {
338		fdx = strtol(dev, &ep, 10);
339		if (*ep == '\0')
340			fd = fdx;
341	}
342
343	/* Identifying device */
344	if (fd >= 0) {
345		struct stat sbuf;
346		char *ndevbas, *lep;
347
348		if (fstat(fd, &sbuf) == -1)
349			err(1, "cannot stat device file descriptor");
350
351		strcpy(ndev, _PATH_DEV);
352		ndevbas = ndev + strlen(_PATH_DEV);
353		devname_r(sbuf.st_rdev, S_IFCHR, ndevbas,
354		          sizeof(ndev) - strlen(_PATH_DEV));
355
356		if (strncmp(ndevbas, "fuse", 4))
357			errx(1, "mounting inappropriate device");
358
359		strtol(ndevbas + 4, &lep, 10);
360		if (*lep != '\0')
361			errx(1, "mounting inappropriate device");
362
363		dev = ndev;
364	}
365
366	if (argc > 0 || daemon_str) {
367		char *fds;
368
369		if (fd < 0 && (fd = open(dev, O_RDWR)) < 0)
370			err(1, "failed to open fuse device");
371
372		if (asprintf(&fds, "%d", fd) == -1)
373			err(1, "failed to allocate memory");
374		setenv("FUSE_DEV_FD", fds, 1);
375		free(fds);
376		setenv("FUSE_NO_MOUNT", "1", 1);
377
378		if (daemon_str) {
379			char *bgdaemon;
380			int len;
381
382			if (! daemon_opts)
383				daemon_opts = __DECONST(char *, "");
384
385			len =  strlen(daemon_str) + 1 + strlen(daemon_opts) +
386			    2 + 1;
387			bgdaemon = calloc(1, len);
388
389			if (! bgdaemon)
390				err(1, "failed to allocate memory");
391
392			strlcpy(bgdaemon, daemon_str, len);
393			strlcat(bgdaemon, " ", len);
394			strlcat(bgdaemon, daemon_opts, len);
395			strlcat(bgdaemon, " &", len);
396
397			if (system(bgdaemon))
398				err(1, "failed to call fuse daemon");
399		} else {
400			if ((pid = fork()) < 0)
401				err(1, "failed to fork for fuse daemon");
402
403			if (pid == 0) {
404				execvp(argv[0], argv);
405				err(1, "failed to exec fuse daemon");
406			}
407		}
408	}
409
410	if (fd >= 0 && ! init_backgrounded() && close(fd) < 0) {
411		if (pid)
412			kill(pid, SIGKILL);
413		err(1, "failed to close fuse device");
414	}
415
416	/* Prepare the options vector for nmount(). build_iovec() is declared
417	 * in mntopts.h. */
418	sprintf(fdstr, "%d", fd);
419	build_iovec(&iov, &iovlen, "fstype", __DECONST(void *, "fusefs"), -1);
420	build_iovec(&iov, &iovlen, "fspath", mntpath, -1);
421	build_iovec(&iov, &iovlen, "from", dev, -1);
422	build_iovec(&iov, &iovlen, "fd", fdstr, -1);
423
424	if (verbose)
425		fprintf(stderr, "mounting fuse daemon on device %s\n", dev);
426
427	if (nmount(iov, iovlen, mntflags) < 0)
428		err(EX_OSERR, "%s on %s", dev, mntpath);
429
430	exit(0);
431}
432
433void
434__usage_short(void) {
435	fprintf(stderr,
436	    "usage:\n%s [-A|-S|-v|-V|-h|-D daemon|-O args|-s special|-m node|-o option...] special node [daemon args...]\n\n",
437	    getprogname());
438}
439
440void
441usage(void)
442{
443	struct mntopt *mo;
444
445	__usage_short();
446
447	fprintf(stderr, "known options:\n");
448	for (mo = mopts; mo->m_flag; ++mo)
449		fprintf(stderr, "\t%s\n", mo->m_option);
450
451	fprintf(stderr, "\n(use -h for a detailed description of these options)\n");
452	exit(EX_USAGE);
453}
454
455void
456helpmsg(void)
457{
458	if (! getenv("MOUNT_FUSEFS_CALL_BY_LIB")) {
459		__usage_short();
460		fprintf(stderr, "description of options:\n");
461	}
462
463	/*
464	 * The main use case of this function is giving info embedded in general
465	 * FUSE lib help output. Therefore the style and the content of the output
466	 * tries to fit there as much as possible.
467	 */
468	fprintf(stderr,
469	        "    -o allow_other         allow access to other users\n"
470	        /* "    -o nonempty            allow mounts over non-empty file/dir\n" */
471	        "    -o default_permissions enable permission checking by kernel\n"
472		/*
473	        "    -o fsname=NAME         set filesystem name\n"
474	        "    -o large_read          issue large read requests (2.4 only)\n"
475		 */
476	        "    -o subtype=NAME        set filesystem type\n"
477	        "    -o max_read=N          set maximum size of read requests\n"
478	        "    -o noprivate           allow secondary mounting of the filesystem\n"
479	        "    -o neglect_shares      don't report EBUSY when unmount attempted\n"
480	        "                           in presence of secondary mounts\n"
481	        "    -o push_symlinks_in    prefix absolute symlinks with mountpoint\n"
482	        "    -o sync_unmount        do unmount synchronously\n"
483	        );
484	exit(EX_USAGE);
485}
486
487void
488showversion(void)
489{
490	puts("mount_fusefs [fuse4bsd] version: " FUSE4BSD_VERSION);
491	exit(EX_USAGE);
492}
493
494int
495init_backgrounded(void)
496{
497	int ibg;
498	size_t len;
499
500	len = sizeof(ibg);
501
502	if (sysctlbyname("vfs.fuse.init_backgrounded", &ibg, &len, NULL, 0))
503		return (0);
504
505	return (ibg);
506}
507