1/*-
2 * SPDX-License-Identifier: BSD-2-Clause
3 *
4 * Copyright (c) 2005 Jean-Sebastien Pedron
5 * Copyright (c) 2005 Csaba Henk
6 * All rights reserved.
7 *
8 * Copyright (c) 2019 The FreeBSD Foundation
9 *
10 * Portions of this software were developed by BFF Storage Systems under
11 * sponsorship from the FreeBSD Foundation.
12 *
13 * Redistribution and use in source and binary forms, with or without
14 * modification, are permitted provided that the following conditions
15 * are met:
16 * 1. Redistributions of source code must retain the above copyright
17 *    notice, this list of conditions and the following disclaimer.
18 * 2. Redistributions in binary form must reproduce the above copyright
19 *    notice, this list of conditions and the following disclaimer in the
20 *    documentation and/or other materials provided with the distribution.
21 *
22 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
23 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
24 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
25 * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
26 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
27 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
28 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
29 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
30 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
31 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
32 * SUCH DAMAGE.
33 *
34 */
35
36#include <sys/param.h>
37#include <sys/mount.h>
38#include <sys/uio.h>
39#include <sys/stat.h>
40#include <sys/sysctl.h>
41
42#include <err.h>
43#include <stdio.h>
44#include <stdlib.h>
45#include <string.h>
46#include <sysexits.h>
47#include <unistd.h>
48#include <fcntl.h>
49#include <signal.h>
50#include <getopt.h>
51#include <limits.h>
52#include <osreldate.h>
53#include <paths.h>
54
55#include "mntopts.h"
56
57#ifndef FUSE4BSD_VERSION
58#define	FUSE4BSD_VERSION	"0.3.9-pre1"
59#endif
60
61void	__usage_short(void);
62void	usage(void);
63void	helpmsg(void);
64void	showversion(void);
65
66static struct mntopt mopts[] = {
67	#define ALTF_PRIVATE 0x01
68	{ "private",             0, ALTF_PRIVATE, 1 },
69	{ "neglect_shares",      0, 0x02, 1 },
70	{ "push_symlinks_in",    0, 0x04, 1 },
71	{ "allow_other",         0, 0x08, 1 },
72	{ "default_permissions", 0, 0x10, 1 },
73	#define ALTF_MAXREAD 0x20
74	{ "max_read=",           0, ALTF_MAXREAD, 1 },
75	#define ALTF_SUBTYPE 0x40
76	{ "subtype=",            0, ALTF_SUBTYPE, 1 },
77	#define ALTF_FSNAME 0x80
78	{ "fsname=",             0, ALTF_FSNAME, 1 },
79	/*
80	 * MOPT_AUTOMOUNTED, included by MOPT_STDOPTS, does not fit into
81	 * the 'flags' argument to nmount(2).  We have to abuse altflags
82	 * to pass it, as string, via iovec.
83	 */
84	#define ALTF_AUTOMOUNTED 0x100
85	{ "automounted",	0, ALTF_AUTOMOUNTED, 1 },
86	#define ALTF_INTR 0x200
87	{ "intr",		0, ALTF_INTR, 1 },
88	/* Linux specific options, we silently ignore them */
89	{ "fd=",                 0, 0x00, 1 },
90	{ "rootmode=",           0, 0x00, 1 },
91	{ "user_id=",            0, 0x00, 1 },
92	{ "group_id=",           0, 0x00, 1 },
93	{ "large_read",          0, 0x00, 1 },
94	/* "nonempty", just the first two chars are stripped off during parsing */
95	{ "nempty",              0, 0x00, 1 },
96	{ "async",               0, MNT_ASYNC, 0},
97	{ "noasync",             1, MNT_ASYNC, 0},
98	MOPT_STDOPTS,
99	MOPT_END
100};
101
102struct mntval {
103	int mv_flag;
104	void *mv_value;
105	int mv_len;
106};
107
108static struct mntval mvals[] = {
109	{ ALTF_MAXREAD, NULL, 0 },
110	{ ALTF_SUBTYPE, NULL, 0 },
111	{ ALTF_FSNAME, NULL, 0 },
112	{ 0, NULL, 0 }
113};
114
115#define DEFAULT_MOUNT_FLAGS ALTF_PRIVATE
116
117int
118main(int argc, char *argv[])
119{
120	struct iovec *iov;
121	int mntflags, iovlen, verbose = 0;
122	char *dev = NULL, *dir = NULL, mntpath[MAXPATHLEN];
123	char *devo = NULL, *diro = NULL;
124	char ndev[128], fdstr[15];
125	int i, done = 0, reject_allow_other = 0, safe_level = 0;
126	int altflags = DEFAULT_MOUNT_FLAGS;
127	int __altflags = DEFAULT_MOUNT_FLAGS;
128	int ch = 0;
129	struct mntopt *mo;
130	struct mntval *mv;
131	static struct option longopts[] = {
132		{"reject-allow_other", no_argument, NULL, 'A'},
133		{"safe", no_argument, NULL, 'S'},
134		{"daemon", required_argument, NULL, 'D'},
135		{"daemon_opts", required_argument, NULL, 'O'},
136		{"special", required_argument, NULL, 's'},
137		{"mountpath", required_argument, NULL, 'm'},
138		{"version", no_argument, NULL, 'V'},
139		{"help", no_argument, NULL, 'h'},
140		{0,0,0,0}
141	};
142	int pid = 0;
143	int fd = -1, fdx;
144	char *ep;
145	char *daemon_str = NULL, *daemon_opts = NULL;
146
147	/*
148	 * We want a parsing routine which is not sensitive to
149	 * the position of args/opts; it should extract the
150	 * first two args and stop at the beginning of the rest.
151	 * (This makes it easier to call mount_fusefs from external
152	 * utils than it is with a strict "util flags args" syntax.)
153	 */
154
155	iov = NULL;
156	iovlen = 0;
157	mntflags = 0;
158	/* All in all, I feel it more robust this way... */
159	unsetenv("POSIXLY_CORRECT");
160	if (getenv("MOUNT_FUSEFS_IGNORE_UNKNOWN"))
161		getmnt_silent = 1;
162	if (getenv("MOUNT_FUSEFS_VERBOSE"))
163		verbose = 1;
164
165	do {
166		for (i = 0; i < 3; i++) {
167			if (optind < argc && argv[optind][0] != '-') {
168				if (dir) {
169					done = 1;
170					break;
171				}
172				if (dev)
173					dir = argv[optind];
174				else
175					dev = argv[optind];
176				optind++;
177			}
178		}
179		switch(ch) {
180		case 'A':
181			reject_allow_other = 1;
182			break;
183		case 'S':
184			safe_level = 1;
185			break;
186		case 'D':
187			if (daemon_str)
188				errx(1, "daemon specified inconsistently");
189			daemon_str = optarg;
190			break;
191		case 'O':
192			if (daemon_opts)
193				errx(1, "daemon opts specified inconsistently");
194			daemon_opts = optarg;
195			break;
196		case 'o':
197			getmntopts(optarg, mopts, &mntflags, &altflags);
198			for (mv = mvals; mv->mv_flag; ++mv) {
199				if (! (altflags & mv->mv_flag))
200					continue;
201				for (mo = mopts; mo->m_flag; ++mo) {
202					char *p, *q;
203
204					if (mo->m_flag != mv->mv_flag)
205						continue;
206					p = strstr(optarg, mo->m_option);
207					if (p) {
208						p += strlen(mo->m_option);
209						q = p;
210						while (*q != '\0' && *q != ',')
211							q++;
212						mv->mv_len = q - p + 1;
213						mv->mv_value = malloc(mv->mv_len);
214						if (mv->mv_value == NULL)
215							err(1, "malloc");
216						memcpy(mv->mv_value, p, mv->mv_len - 1);
217						((char *)mv->mv_value)[mv->mv_len - 1] = '\0';
218						break;
219					}
220				}
221			}
222			break;
223		case 's':
224			if (devo)
225				errx(1, "special specified inconsistently");
226			devo = optarg;
227			break;
228		case 'm':
229			if (diro)
230				errx(1, "mount path specified inconsistently");
231			diro = optarg;
232			break;
233		case 'v':
234			verbose = 1;
235			break;
236		case 'h':
237			helpmsg();
238			break;
239		case 'V':
240			showversion();
241			break;
242		case '\0':
243			break;
244		case '?':
245		default:
246			usage();
247		}
248		if (done)
249			break;
250	} while ((ch = getopt_long(argc, argv, "AvVho:SD:O:s:m:", longopts, NULL)) != -1);
251
252	argc -= optind;
253	argv += optind;
254
255	if (devo) {
256		if (dev)
257			errx(1, "special specified inconsistently");
258		dev = devo;
259	} else if (diro)
260		errx(1, "if mountpoint is given via an option, special should also be given via an option");
261
262	if (diro) {
263		if (dir)
264			errx(1, "mount path specified inconsistently");
265		dir = diro;
266	}
267
268	if ((! dev) && argc > 0) {
269		dev = *argv++;
270		argc--;
271	}
272
273	if ((! dir) && argc > 0) {
274		dir = *argv++;
275		argc--;
276	}
277
278	if (! (dev && dir))
279		errx(1, "missing special and/or mountpoint");
280
281	for (mo = mopts; mo->m_flag; ++mo) {
282		if (altflags & mo->m_flag) {
283			int iov_done = 0;
284
285			if (reject_allow_other &&
286			    strcmp(mo->m_option, "allow_other") == 0)
287				/*
288				 * reject_allow_other is stronger than a
289				 * negative of allow_other: if this is set,
290				 * allow_other is blocked, period.
291				 */
292				errx(1, "\"allow_other\" usage is banned by respective option");
293
294			for (mv = mvals; mv->mv_flag; ++mv) {
295				if (mo->m_flag != mv->mv_flag)
296					continue;
297				if (mv->mv_value) {
298					build_iovec(&iov, &iovlen, mo->m_option, mv->mv_value, mv->mv_len);
299					iov_done = 1;
300					break;
301				}
302			}
303			if (! iov_done)
304				build_iovec(&iov, &iovlen, mo->m_option,
305				    __DECONST(void *, ""), -1);
306		}
307		if (__altflags & mo->m_flag) {
308			char *uscore_opt;
309
310			if (asprintf(&uscore_opt, "__%s", mo->m_option) == -1)
311				err(1, "failed to allocate memory");
312			build_iovec(&iov, &iovlen, uscore_opt,
313			    __DECONST(void *, ""), -1);
314			free(uscore_opt);
315		}
316	}
317
318	if (getenv("MOUNT_FUSEFS_SAFE"))
319		safe_level = 1;
320
321	if (safe_level > 0 && (argc > 0 || daemon_str || daemon_opts))
322		errx(1, "safe mode, spawning daemon not allowed");
323
324	if ((argc > 0 && (daemon_str || daemon_opts)) ||
325	    (daemon_opts && ! daemon_str))
326		errx(1, "daemon specified inconsistently");
327
328	/*
329	 * Resolve the mountpoint with realpath(3) and remove unnecessary
330	 * slashes from the devicename if there are any.
331	 */
332	if (checkpath(dir, mntpath) != 0)
333		err(1, "%s", mntpath);
334	(void)rmslashes(dev, dev);
335
336	if (strcmp(dev, "auto") == 0)
337		dev = __DECONST(char *, "/dev/fuse");
338
339	if (strcmp(dev, "/dev/fuse") == 0) {
340		if (! (argc > 0 || daemon_str)) {
341			fprintf(stderr, "Please also specify the fuse daemon to run when mounting via the multiplexer!\n");
342			usage();
343		}
344		if ((fd = open(dev, O_RDWR)) < 0)
345			err(1, "failed to open fuse device");
346	} else {
347		fdx = strtol(dev, &ep, 10);
348		if (*ep == '\0')
349			fd = fdx;
350	}
351
352	/* Identifying device */
353	if (fd >= 0) {
354		struct stat sbuf;
355		char *ndevbas, *lep;
356
357		if (fstat(fd, &sbuf) == -1)
358			err(1, "cannot stat device file descriptor");
359
360		strcpy(ndev, _PATH_DEV);
361		ndevbas = ndev + strlen(_PATH_DEV);
362		devname_r(sbuf.st_rdev, S_IFCHR, ndevbas,
363		          sizeof(ndev) - strlen(_PATH_DEV));
364
365		if (strncmp(ndevbas, "fuse", 4))
366			errx(1, "mounting inappropriate device");
367
368		strtol(ndevbas + 4, &lep, 10);
369		if (*lep != '\0')
370			errx(1, "mounting inappropriate device");
371
372		dev = ndev;
373	}
374
375	if (argc > 0 || daemon_str) {
376		char *fds;
377
378		if (fd < 0 && (fd = open(dev, O_RDWR)) < 0)
379			err(1, "failed to open fuse device");
380
381		if (asprintf(&fds, "%d", fd) == -1)
382			err(1, "failed to allocate memory");
383		setenv("FUSE_DEV_FD", fds, 1);
384		free(fds);
385		setenv("FUSE_NO_MOUNT", "1", 1);
386
387		if (daemon_str) {
388			char *bgdaemon;
389			int len;
390
391			if (! daemon_opts)
392				daemon_opts = __DECONST(char *, "");
393
394			len =  strlen(daemon_str) + 1 + strlen(daemon_opts) +
395			    2 + 1;
396			bgdaemon = calloc(1, len);
397
398			if (! bgdaemon)
399				err(1, "failed to allocate memory");
400
401			strlcpy(bgdaemon, daemon_str, len);
402			strlcat(bgdaemon, " ", len);
403			strlcat(bgdaemon, daemon_opts, len);
404			strlcat(bgdaemon, " &", len);
405
406			if (system(bgdaemon))
407				err(1, "failed to call fuse daemon");
408		} else {
409			if ((pid = fork()) < 0)
410				err(1, "failed to fork for fuse daemon");
411
412			if (pid == 0) {
413				execvp(argv[0], argv);
414				err(1, "failed to exec fuse daemon");
415			}
416		}
417	}
418
419	/* Prepare the options vector for nmount(). build_iovec() is declared
420	 * in mntopts.h. */
421	sprintf(fdstr, "%d", fd);
422	build_iovec(&iov, &iovlen, "fstype", __DECONST(void *, "fusefs"), -1);
423	build_iovec(&iov, &iovlen, "fspath", mntpath, -1);
424	build_iovec(&iov, &iovlen, "from", dev, -1);
425	build_iovec(&iov, &iovlen, "fd", fdstr, -1);
426
427	if (verbose)
428		fprintf(stderr, "mounting fuse daemon on device %s\n", dev);
429
430	if (nmount(iov, iovlen, mntflags) < 0)
431		err(EX_OSERR, "%s on %s", dev, mntpath);
432
433	exit(0);
434}
435
436void
437__usage_short(void) {
438	fprintf(stderr,
439	    "usage:\n%s [-A|-S|-v|-V|-h|-D daemon|-O args|-s special|-m node|-o option...] special node [daemon args...]\n\n",
440	    getprogname());
441}
442
443void
444usage(void)
445{
446	struct mntopt *mo;
447
448	__usage_short();
449
450	fprintf(stderr, "known options:\n");
451	for (mo = mopts; mo->m_flag; ++mo)
452		fprintf(stderr, "\t%s\n", mo->m_option);
453
454	fprintf(stderr, "\n(use -h for a detailed description of these options)\n");
455	exit(EX_USAGE);
456}
457
458void
459helpmsg(void)
460{
461	if (! getenv("MOUNT_FUSEFS_CALL_BY_LIB")) {
462		__usage_short();
463		fprintf(stderr, "description of options:\n");
464	}
465
466	/*
467	 * The main use case of this function is giving info embedded in general
468	 * FUSE lib help output. Therefore the style and the content of the output
469	 * tries to fit there as much as possible.
470	 */
471	fprintf(stderr,
472	        "    -o allow_other         allow access to other users\n"
473	        /* "    -o nonempty            allow mounts over non-empty file/dir\n" */
474	        "    -o default_permissions enable permission checking by kernel\n"
475		"    -o intr                interruptible mount\n"
476	        "    -o fsname=NAME         set filesystem name\n"
477		/*
478	        "    -o large_read          issue large read requests (2.4 only)\n"
479		 */
480	        "    -o subtype=NAME        set filesystem type\n"
481	        "    -o max_read=N          set maximum size of read requests\n"
482	        "    -o noprivate           allow secondary mounting of the filesystem\n"
483	        "    -o neglect_shares      don't report EBUSY when unmount attempted\n"
484	        "                           in presence of secondary mounts\n"
485	        "    -o push_symlinks_in    prefix absolute symlinks with mountpoint\n"
486	        );
487	exit(EX_USAGE);
488}
489
490void
491showversion(void)
492{
493	puts("mount_fusefs [fuse4bsd] version: " FUSE4BSD_VERSION);
494	exit(EX_USAGE);
495}
496