1/*-
2 * SPDX-License-Identifier: BSD-2-Clause-FreeBSD
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/cdefs.h>
37__FBSDID("$FreeBSD$");
38
39#include <sys/param.h>
40#include <sys/mount.h>
41#include <sys/uio.h>
42#include <sys/stat.h>
43#include <sys/sysctl.h>
44
45#include <err.h>
46#include <stdio.h>
47#include <stdlib.h>
48#include <string.h>
49#include <sysexits.h>
50#include <unistd.h>
51#include <fcntl.h>
52#include <signal.h>
53#include <getopt.h>
54#include <limits.h>
55#include <osreldate.h>
56#include <paths.h>
57
58#include "mntopts.h"
59
60#ifndef FUSE4BSD_VERSION
61#define	FUSE4BSD_VERSION	"0.3.9-pre1"
62#endif
63
64void	__usage_short(void);
65void	usage(void);
66void	helpmsg(void);
67void	showversion(void);
68
69static struct mntopt mopts[] = {
70	#define ALTF_PRIVATE 0x01
71	{ "private",             0, ALTF_PRIVATE, 1 },
72	{ "neglect_shares",      0, 0x02, 1 },
73	{ "push_symlinks_in",    0, 0x04, 1 },
74	{ "allow_other",         0, 0x08, 1 },
75	{ "default_permissions", 0, 0x10, 1 },
76	#define ALTF_MAXREAD 0x20
77	{ "max_read=",           0, ALTF_MAXREAD, 1 },
78	#define ALTF_SUBTYPE 0x40
79	{ "subtype=",            0, ALTF_SUBTYPE, 1 },
80	/*
81	 * MOPT_AUTOMOUNTED, included by MOPT_STDOPTS, does not fit into
82	 * the 'flags' argument to nmount(2).  We have to abuse altflags
83	 * to pass it, as string, via iovec.
84	 */
85	#define ALTF_AUTOMOUNTED 0x100
86	{ "automounted",	0, ALTF_AUTOMOUNTED, 1 },
87	#define ALTF_INTR 0x200
88	{ "intr",		0, ALTF_INTR, 1 },
89	/* Linux specific options, we silently ignore them */
90	{ "fsname=",             0, 0x00, 1 },
91	{ "fd=",                 0, 0x00, 1 },
92	{ "rootmode=",           0, 0x00, 1 },
93	{ "user_id=",            0, 0x00, 1 },
94	{ "group_id=",           0, 0x00, 1 },
95	{ "large_read",          0, 0x00, 1 },
96	/* "nonempty", just the first two chars are stripped off during parsing */
97	{ "nempty",              0, 0x00, 1 },
98	{ "async",               0, MNT_ASYNC, 0},
99	{ "noasync",             1, MNT_ASYNC, 0},
100	MOPT_STDOPTS,
101	MOPT_END
102};
103
104struct mntval {
105	int mv_flag;
106	void *mv_value;
107	int mv_len;
108};
109
110static struct mntval mvals[] = {
111	{ ALTF_MAXREAD, NULL, 0 },
112	{ ALTF_SUBTYPE, NULL, 0 },
113	{ 0, NULL, 0 }
114};
115
116#define DEFAULT_MOUNT_FLAGS ALTF_PRIVATE
117
118int
119main(int argc, char *argv[])
120{
121	struct iovec *iov;
122	int mntflags, iovlen, verbose = 0;
123	char *dev = NULL, *dir = NULL, mntpath[MAXPATHLEN];
124	char *devo = NULL, *diro = NULL;
125	char ndev[128], fdstr[15];
126	int i, done = 0, reject_allow_other = 0, safe_level = 0;
127	int altflags = DEFAULT_MOUNT_FLAGS;
128	int __altflags = DEFAULT_MOUNT_FLAGS;
129	int ch = 0;
130	struct mntopt *mo;
131	struct mntval *mv;
132	static struct option longopts[] = {
133		{"reject-allow_other", no_argument, NULL, 'A'},
134		{"safe", no_argument, NULL, 'S'},
135		{"daemon", required_argument, NULL, 'D'},
136		{"daemon_opts", required_argument, NULL, 'O'},
137		{"special", required_argument, NULL, 's'},
138		{"mountpath", required_argument, NULL, 'm'},
139		{"version", no_argument, NULL, 'V'},
140		{"help", no_argument, NULL, 'h'},
141		{0,0,0,0}
142	};
143	int pid = 0;
144	int fd = -1, fdx;
145	char *ep;
146	char *daemon_str = NULL, *daemon_opts = NULL;
147
148	/*
149	 * We want a parsing routine which is not sensitive to
150	 * the position of args/opts; it should extract the
151	 * first two args and stop at the beginning of the rest.
152	 * (This makes it easier to call mount_fusefs from external
153	 * utils than it is with a strict "util flags args" syntax.)
154	 */
155
156	iov = NULL;
157	iovlen = 0;
158	mntflags = 0;
159	/* All in all, I feel it more robust this way... */
160	unsetenv("POSIXLY_CORRECT");
161	if (getenv("MOUNT_FUSEFS_IGNORE_UNKNOWN"))
162		getmnt_silent = 1;
163	if (getenv("MOUNT_FUSEFS_VERBOSE"))
164		verbose = 1;
165
166	do {
167		for (i = 0; i < 3; i++) {
168			if (optind < argc && argv[optind][0] != '-') {
169				if (dir) {
170					done = 1;
171					break;
172				}
173				if (dev)
174					dir = argv[optind];
175				else
176					dev = argv[optind];
177				optind++;
178			}
179		}
180		switch(ch) {
181		case 'A':
182			reject_allow_other = 1;
183			break;
184		case 'S':
185			safe_level = 1;
186			break;
187		case 'D':
188			if (daemon_str)
189				errx(1, "daemon specified inconsistently");
190			daemon_str = optarg;
191			break;
192		case 'O':
193			if (daemon_opts)
194				errx(1, "daemon opts specified inconsistently");
195			daemon_opts = optarg;
196			break;
197		case 'o':
198			getmntopts(optarg, mopts, &mntflags, &altflags);
199			for (mv = mvals; mv->mv_flag; ++mv) {
200				if (! (altflags & mv->mv_flag))
201					continue;
202				for (mo = mopts; mo->m_flag; ++mo) {
203					char *p, *q;
204
205					if (mo->m_flag != mv->mv_flag)
206						continue;
207					p = strstr(optarg, mo->m_option);
208					if (p) {
209						p += strlen(mo->m_option);
210						q = p;
211						while (*q != '\0' && *q != ',')
212							q++;
213						mv->mv_len = q - p + 1;
214						mv->mv_value = malloc(mv->mv_len);
215						if (mv->mv_value == NULL)
216							err(1, "malloc");
217						memcpy(mv->mv_value, p, mv->mv_len - 1);
218						((char *)mv->mv_value)[mv->mv_len - 1] = '\0';
219						break;
220					}
221				}
222			}
223			break;
224		case 's':
225			if (devo)
226				errx(1, "special specified inconsistently");
227			devo = optarg;
228			break;
229		case 'm':
230			if (diro)
231				errx(1, "mount path specified inconsistently");
232			diro = optarg;
233			break;
234		case 'v':
235			verbose = 1;
236			break;
237		case 'h':
238			helpmsg();
239			break;
240		case 'V':
241			showversion();
242			break;
243		case '\0':
244			break;
245		case '?':
246		default:
247			usage();
248		}
249		if (done)
250			break;
251	} while ((ch = getopt_long(argc, argv, "AvVho:SD:O:s:m:", longopts, NULL)) != -1);
252
253	argc -= optind;
254	argv += optind;
255
256	if (devo) {
257		if (dev)
258			errx(1, "special specified inconsistently");
259		dev = devo;
260	} else if (diro)
261		errx(1, "if mountpoint is given via an option, special should also be given via an option");
262
263	if (diro) {
264		if (dir)
265			errx(1, "mount path specified inconsistently");
266		dir = diro;
267	}
268
269	if ((! dev) && argc > 0) {
270		dev = *argv++;
271		argc--;
272	}
273
274	if ((! dir) && argc > 0) {
275		dir = *argv++;
276		argc--;
277	}
278
279	if (! (dev && dir))
280		errx(1, "missing special and/or mountpoint");
281
282	for (mo = mopts; mo->m_flag; ++mo) {
283		if (altflags & mo->m_flag) {
284			int iov_done = 0;
285
286			if (reject_allow_other &&
287			    strcmp(mo->m_option, "allow_other") == 0)
288				/*
289				 * reject_allow_other is stronger than a
290				 * negative of allow_other: if this is set,
291				 * allow_other is blocked, period.
292				 */
293				errx(1, "\"allow_other\" usage is banned by respective option");
294
295			for (mv = mvals; mv->mv_flag; ++mv) {
296				if (mo->m_flag != mv->mv_flag)
297					continue;
298				if (mv->mv_value) {
299					build_iovec(&iov, &iovlen, mo->m_option, mv->mv_value, mv->mv_len);
300					iov_done = 1;
301					break;
302				}
303			}
304			if (! iov_done)
305				build_iovec(&iov, &iovlen, mo->m_option,
306				    __DECONST(void *, ""), -1);
307		}
308		if (__altflags & mo->m_flag) {
309			char *uscore_opt;
310
311			if (asprintf(&uscore_opt, "__%s", mo->m_option) == -1)
312				err(1, "failed to allocate memory");
313			build_iovec(&iov, &iovlen, uscore_opt,
314			    __DECONST(void *, ""), -1);
315			free(uscore_opt);
316		}
317	}
318
319	if (getenv("MOUNT_FUSEFS_SAFE"))
320		safe_level = 1;
321
322	if (safe_level > 0 && (argc > 0 || daemon_str || daemon_opts))
323		errx(1, "safe mode, spawning daemon not allowed");
324
325	if ((argc > 0 && (daemon_str || daemon_opts)) ||
326	    (daemon_opts && ! daemon_str))
327		errx(1, "daemon specified inconsistently");
328
329	/*
330	 * Resolve the mountpoint with realpath(3) and remove unnecessary
331	 * slashes from the devicename if there are any.
332	 */
333	if (checkpath(dir, mntpath) != 0)
334		err(1, "%s", mntpath);
335	(void)rmslashes(dev, dev);
336
337	if (strcmp(dev, "auto") == 0)
338		dev = __DECONST(char *, "/dev/fuse");
339
340	if (strcmp(dev, "/dev/fuse") == 0) {
341		if (! (argc > 0 || daemon_str)) {
342			fprintf(stderr, "Please also specify the fuse daemon to run when mounting via the multiplexer!\n");
343			usage();
344		}
345		if ((fd = open(dev, O_RDWR)) < 0)
346			err(1, "failed to open fuse device");
347	} else {
348		fdx = strtol(dev, &ep, 10);
349		if (*ep == '\0')
350			fd = fdx;
351	}
352
353	/* Identifying device */
354	if (fd >= 0) {
355		struct stat sbuf;
356		char *ndevbas, *lep;
357
358		if (fstat(fd, &sbuf) == -1)
359			err(1, "cannot stat device file descriptor");
360
361		strcpy(ndev, _PATH_DEV);
362		ndevbas = ndev + strlen(_PATH_DEV);
363		devname_r(sbuf.st_rdev, S_IFCHR, ndevbas,
364		          sizeof(ndev) - strlen(_PATH_DEV));
365
366		if (strncmp(ndevbas, "fuse", 4))
367			errx(1, "mounting inappropriate device");
368
369		strtol(ndevbas + 4, &lep, 10);
370		if (*lep != '\0')
371			errx(1, "mounting inappropriate device");
372
373		dev = ndev;
374	}
375
376	if (argc > 0 || daemon_str) {
377		char *fds;
378
379		if (fd < 0 && (fd = open(dev, O_RDWR)) < 0)
380			err(1, "failed to open fuse device");
381
382		if (asprintf(&fds, "%d", fd) == -1)
383			err(1, "failed to allocate memory");
384		setenv("FUSE_DEV_FD", fds, 1);
385		free(fds);
386		setenv("FUSE_NO_MOUNT", "1", 1);
387
388		if (daemon_str) {
389			char *bgdaemon;
390			int len;
391
392			if (! daemon_opts)
393				daemon_opts = __DECONST(char *, "");
394
395			len =  strlen(daemon_str) + 1 + strlen(daemon_opts) +
396			    2 + 1;
397			bgdaemon = calloc(1, len);
398
399			if (! bgdaemon)
400				err(1, "failed to allocate memory");
401
402			strlcpy(bgdaemon, daemon_str, len);
403			strlcat(bgdaemon, " ", len);
404			strlcat(bgdaemon, daemon_opts, len);
405			strlcat(bgdaemon, " &", len);
406
407			if (system(bgdaemon))
408				err(1, "failed to call fuse daemon");
409		} else {
410			if ((pid = fork()) < 0)
411				err(1, "failed to fork for fuse daemon");
412
413			if (pid == 0) {
414				execvp(argv[0], argv);
415				err(1, "failed to exec fuse daemon");
416			}
417		}
418	}
419
420	/* Prepare the options vector for nmount(). build_iovec() is declared
421	 * in mntopts.h. */
422	sprintf(fdstr, "%d", fd);
423	build_iovec(&iov, &iovlen, "fstype", __DECONST(void *, "fusefs"), -1);
424	build_iovec(&iov, &iovlen, "fspath", mntpath, -1);
425	build_iovec(&iov, &iovlen, "from", dev, -1);
426	build_iovec(&iov, &iovlen, "fd", fdstr, -1);
427
428	if (verbose)
429		fprintf(stderr, "mounting fuse daemon on device %s\n", dev);
430
431	if (nmount(iov, iovlen, mntflags) < 0)
432		err(EX_OSERR, "%s on %s", dev, mntpath);
433
434	exit(0);
435}
436
437void
438__usage_short(void) {
439	fprintf(stderr,
440	    "usage:\n%s [-A|-S|-v|-V|-h|-D daemon|-O args|-s special|-m node|-o option...] special node [daemon args...]\n\n",
441	    getprogname());
442}
443
444void
445usage(void)
446{
447	struct mntopt *mo;
448
449	__usage_short();
450
451	fprintf(stderr, "known options:\n");
452	for (mo = mopts; mo->m_flag; ++mo)
453		fprintf(stderr, "\t%s\n", mo->m_option);
454
455	fprintf(stderr, "\n(use -h for a detailed description of these options)\n");
456	exit(EX_USAGE);
457}
458
459void
460helpmsg(void)
461{
462	if (! getenv("MOUNT_FUSEFS_CALL_BY_LIB")) {
463		__usage_short();
464		fprintf(stderr, "description of options:\n");
465	}
466
467	/*
468	 * The main use case of this function is giving info embedded in general
469	 * FUSE lib help output. Therefore the style and the content of the output
470	 * tries to fit there as much as possible.
471	 */
472	fprintf(stderr,
473	        "    -o allow_other         allow access to other users\n"
474	        /* "    -o nonempty            allow mounts over non-empty file/dir\n" */
475	        "    -o default_permissions enable permission checking by kernel\n"
476		"    -o intr                interruptible mount\n"
477		/*
478	        "    -o fsname=NAME         set filesystem name\n"
479	        "    -o large_read          issue large read requests (2.4 only)\n"
480		 */
481	        "    -o subtype=NAME        set filesystem type\n"
482	        "    -o max_read=N          set maximum size of read requests\n"
483	        "    -o noprivate           allow secondary mounting of the filesystem\n"
484	        "    -o neglect_shares      don't report EBUSY when unmount attempted\n"
485	        "                           in presence of secondary mounts\n"
486	        "    -o push_symlinks_in    prefix absolute symlinks with mountpoint\n"
487	        );
488	exit(EX_USAGE);
489}
490
491void
492showversion(void)
493{
494	puts("mount_fusefs [fuse4bsd] version: " FUSE4BSD_VERSION);
495	exit(EX_USAGE);
496}
497