xref: /freebsd/sbin/mount/mount.c (revision 6e8394b8baa7d5d9153ab90de6824bcd19b3b4e1)
1 /*-
2  * Copyright (c) 1980, 1989, 1993, 1994
3  *	The Regents of the University of California.  All rights reserved.
4  *
5  * Redistribution and use in source and binary forms, with or without
6  * modification, are permitted provided that the following conditions
7  * are met:
8  * 1. Redistributions of source code must retain the above copyright
9  *    notice, this list of conditions and the following disclaimer.
10  * 2. Redistributions in binary form must reproduce the above copyright
11  *    notice, this list of conditions and the following disclaimer in the
12  *    documentation and/or other materials provided with the distribution.
13  * 3. All advertising materials mentioning features or use of this software
14  *    must display the following acknowledgement:
15  *	This product includes software developed by the University of
16  *	California, Berkeley and its contributors.
17  * 4. Neither the name of the University nor the names of its contributors
18  *    may be used to endorse or promote products derived from this software
19  *    without specific prior written permission.
20  *
21  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
22  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
23  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
24  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
25  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
26  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
27  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
28  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
29  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
30  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
31  * SUCH DAMAGE.
32  */
33 
34 #ifndef lint
35 static const char copyright[] =
36 "@(#) Copyright (c) 1980, 1989, 1993, 1994\n\
37 	The Regents of the University of California.  All rights reserved.\n";
38 #endif /* not lint */
39 
40 #ifndef lint
41 #if 0
42 static char sccsid[] = "@(#)mount.c	8.25 (Berkeley) 5/8/95";
43 #endif
44 static const char rcsid[] =
45 	"$Id: mount.c,v 1.30 1999/05/07 05:22:08 jkoshy Exp $";
46 #endif /* not lint */
47 
48 #include <sys/param.h>
49 #include <sys/mount.h>
50 #include <sys/stat.h>
51 #include <sys/wait.h>
52 
53 #include <err.h>
54 #include <errno.h>
55 #include <fstab.h>
56 #include <pwd.h>
57 #include <signal.h>
58 #include <stdio.h>
59 #include <stdlib.h>
60 #include <string.h>
61 #include <unistd.h>
62 
63 #include "extern.h"
64 #include "pathnames.h"
65 
66 /* `meta' options */
67 #define MOUNT_META_OPTION_FSTAB		"fstab"
68 #define MOUNT_META_OPTION_CURRENT	"current"
69 
70 int debug, fstab_style, verbose;
71 
72 char   *catopt __P((char *, const char *));
73 struct statfs
74        *getmntpt __P((const char *));
75 int	hasopt __P((const char *, const char *));
76 int	ismounted __P((struct fstab *, struct statfs *, int));
77 int	isremountable __P((const char *));
78 void	mangle __P((char *, int *, const char **));
79 char   *update_options __P((char *, char *, int));
80 int	mountfs __P((const char *, const char *, const char *,
81 			int, const char *, const char *));
82 void	remopt __P((char *, const char *));
83 void	prmount __P((struct statfs *));
84 void	putfsent __P((const struct statfs *));
85 void	usage __P((void));
86 char   *flags2opts __P((int));
87 
88 /* Map from mount options to printable formats. */
89 static struct opt {
90 	int o_opt;
91 	const char *o_name;
92 } optnames[] = {
93 	{ MNT_ASYNC,		"asynchronous" },
94 	{ MNT_EXPORTED,		"NFS exported" },
95 	{ MNT_LOCAL,		"local" },
96 	{ MNT_NOATIME,		"noatime" },
97 	{ MNT_NODEV,		"nodev" },
98 	{ MNT_NOEXEC,		"noexec" },
99 	{ MNT_NOSUID,		"nosuid" },
100 	{ MNT_NOSYMFOLLOW,	"nosymfollow" },
101 	{ MNT_QUOTA,		"with quotas" },
102 	{ MNT_RDONLY,		"read-only" },
103 	{ MNT_SYNCHRONOUS,	"synchronous" },
104 	{ MNT_UNION,		"union" },
105 	{ MNT_NOCLUSTERR,	"noclusterr" },
106 	{ MNT_NOCLUSTERW,	"noclusterw" },
107 	{ MNT_SUIDDIR,		"suiddir" },
108 	{ MNT_SOFTDEP,		"soft-updates" },
109 	{ 0, NULL }
110 };
111 
112 /*
113  * List of VFS types that can be remounted without becoming mounted on top
114  * of each other.
115  * XXX Is this list correct?
116  */
117 static const char *
118 remountable_fs_names[] = {
119 	"ufs", "ffs", "lfs", "ext2fs",
120 	0
121 };
122 
123 int
124 main(argc, argv)
125 	int argc;
126 	char * const argv[];
127 {
128 	const char *mntfromname, **vfslist, *vfstype;
129 	struct fstab *fs;
130 	struct statfs *mntbuf;
131 	FILE *mountdfp;
132 	pid_t pid;
133 	int all, ch, i, init_flags, mntsize, rval;
134 	char *options;
135 
136 	all = init_flags = 0;
137 	options = NULL;
138 	vfslist = NULL;
139 	vfstype = "ufs";
140 	while ((ch = getopt(argc, argv, "adfo:prwt:uv")) != -1)
141 		switch (ch) {
142 		case 'a':
143 			all = 1;
144 			break;
145 		case 'd':
146 			debug = 1;
147 			break;
148 		case 'f':
149 			init_flags |= MNT_FORCE;
150 			break;
151 		case 'o':
152 			if (*optarg)
153 				options = catopt(options, optarg);
154 			break;
155 		case 'p':
156 			fstab_style = 1;
157 			verbose = 1;
158 			break;
159 		case 'r':
160 			init_flags |= MNT_RDONLY;
161 			break;
162 		case 't':
163 			if (vfslist != NULL)
164 				errx(1, "only one -t option may be specified");
165 			vfslist = makevfslist(optarg);
166 			vfstype = optarg;
167 			break;
168 		case 'u':
169 			init_flags |= MNT_UPDATE;
170 			break;
171 		case 'v':
172 			verbose = 1;
173 			break;
174 		case 'w':
175 			init_flags &= ~MNT_RDONLY;
176 			break;
177 		case '?':
178 		default:
179 			usage();
180 			/* NOTREACHED */
181 		}
182 	argc -= optind;
183 	argv += optind;
184 
185 #define	BADTYPE(type)							\
186 	(strcmp(type, FSTAB_RO) &&					\
187 	    strcmp(type, FSTAB_RW) && strcmp(type, FSTAB_RQ))
188 
189 	rval = 0;
190 	switch (argc) {
191 	case 0:
192 		if ((mntsize = getmntinfo(&mntbuf, MNT_NOWAIT)) == 0)
193 			err(1, "getmntinfo");
194 		if (all) {
195 			while ((fs = getfsent()) != NULL) {
196 				if (BADTYPE(fs->fs_type))
197 					continue;
198 				if (checkvfsname(fs->fs_vfstype, vfslist))
199 					continue;
200 				if (hasopt(fs->fs_mntops, "noauto"))
201 					continue;
202 				if (!(init_flags & MNT_UPDATE) &&
203 				    ismounted(fs, mntbuf, mntsize))
204 					continue;
205 				if (mountfs(fs->fs_vfstype, fs->fs_spec,
206 				    fs->fs_file, init_flags, options,
207 				    fs->fs_mntops))
208 					rval = 1;
209 			}
210 		} else if (fstab_style) {
211 			for (i = 0; i < mntsize; i++) {
212 				if (checkvfsname(mntbuf[i].f_fstypename, vfslist))
213 					continue;
214 				putfsent(&mntbuf[i]);
215 			}
216 		} else {
217 			for (i = 0; i < mntsize; i++) {
218 				if (checkvfsname(mntbuf[i].f_fstypename,
219 				    vfslist))
220 					continue;
221 				prmount(&mntbuf[i]);
222 			}
223 		}
224 		exit(rval);
225 	case 1:
226 		if (vfslist != NULL)
227 			usage();
228 
229 		if (init_flags & MNT_UPDATE) {
230 			if ((mntbuf = getmntpt(*argv)) == NULL)
231 				errx(1,
232 				    "unknown special file or file system %s",
233 				    *argv);
234 			if ((fs = getfsfile(mntbuf->f_mntonname)) != NULL) {
235 				mntfromname = fs->fs_spec;
236 				options = update_options(options, fs->fs_mntops,
237 				    mntbuf->f_flags);
238 			} else {
239 				mntfromname = mntbuf->f_mntfromname;
240 				options = update_options(options, NULL,
241 				    mntbuf->f_flags);
242 			}
243 			rval = mountfs(mntbuf->f_fstypename, mntfromname,
244 			    mntbuf->f_mntonname, init_flags, options, 0);
245 			break;
246 		}
247 		if ((fs = getfsfile(*argv)) == NULL &&
248 		    (fs = getfsspec(*argv)) == NULL)
249 			errx(1, "%s: unknown special file or file system",
250 			    *argv);
251 		if (BADTYPE(fs->fs_type))
252 			errx(1, "%s has unknown file system type",
253 			    *argv);
254 		rval = mountfs(fs->fs_vfstype, fs->fs_spec, fs->fs_file,
255 		    init_flags, options, fs->fs_mntops);
256 		break;
257 	case 2:
258 		/*
259 		 * If -t flag has not been specified, and spec contains either
260 		 * a ':' or a '@' then assume that an NFS filesystem is being
261 		 * specified ala Sun.
262 		 */
263 		if (vfslist == NULL && strpbrk(argv[0], ":@") != NULL)
264 			vfstype = "nfs";
265 		rval = mountfs(vfstype,
266 		    argv[0], argv[1], init_flags, options, NULL);
267 		break;
268 	default:
269 		usage();
270 		/* NOTREACHED */
271 	}
272 
273 	/*
274 	 * If the mount was successfully, and done by root, tell mountd the
275 	 * good news.  Pid checks are probably unnecessary, but don't hurt.
276 	 */
277 	if (rval == 0 && getuid() == 0 &&
278 	    (mountdfp = fopen(_PATH_MOUNTDPID, "r")) != NULL) {
279 		if (fscanf(mountdfp, "%d", &pid) == 1 &&
280 		     pid > 0 && kill(pid, SIGHUP) == -1 && errno != ESRCH)
281 			err(1, "signal mountd");
282 		(void)fclose(mountdfp);
283 	}
284 
285 	exit(rval);
286 }
287 
288 int
289 ismounted(fs, mntbuf, mntsize)
290 	struct fstab *fs;
291 	struct statfs *mntbuf;
292 	int mntsize;
293 {
294 	int i;
295 
296 	if (fs->fs_file[0] == '/' && fs->fs_file[1] == '\0')
297 		/* the root file system can always be remounted */
298 		return (0);
299 
300 	for (i = mntsize - 1; i >= 0; --i)
301 		if (strcmp(fs->fs_file, mntbuf[i].f_mntonname) == 0 &&
302 		    (!isremountable(fs->fs_vfstype) ||
303 		     strcmp(fs->fs_spec, mntbuf[i].f_mntfromname) == 0))
304 			return (1);
305 	return (0);
306 }
307 
308 int
309 isremountable(vfsname)
310 	const char *vfsname;
311 {
312 	const char **cp;
313 
314 	for (cp = remountable_fs_names; *cp; cp++)
315 		if (strcmp(*cp, vfsname) == 0)
316 			return (1);
317 	return (0);
318 }
319 
320 int
321 hasopt(mntopts, option)
322 	const char *mntopts, *option;
323 {
324 	int negative, found;
325 	char *opt, *optbuf;
326 
327 	if (option[0] == 'n' && option[1] == 'o') {
328 		negative = 1;
329 		option += 2;
330 	} else
331 		negative = 0;
332 	optbuf = strdup(mntopts);
333 	found = 0;
334 	for (opt = optbuf; (opt = strtok(opt, ",")) != NULL; opt = NULL) {
335 		if (opt[0] == 'n' && opt[1] == 'o') {
336 			if (!strcasecmp(opt + 2, option))
337 				found = negative;
338 		} else if (!strcasecmp(opt, option))
339 			found = !negative;
340 	}
341 	free(optbuf);
342 	return (found);
343 }
344 
345 int
346 mountfs(vfstype, spec, name, flags, options, mntopts)
347 	const char *vfstype, *spec, *name, *options, *mntopts;
348 	int flags;
349 {
350 	/* List of directories containing mount_xxx subcommands. */
351 	static const char *edirs[] = {
352 		_PATH_SBIN,
353 		_PATH_USRSBIN,
354 		NULL
355 	};
356 	const char *argv[100], **edir;
357 	struct stat sb;
358 	struct statfs sf;
359 	pid_t pid;
360 	int argc, i, status;
361 	char *optbuf, execname[MAXPATHLEN + 1], mntpath[MAXPATHLEN];
362 
363 #if __GNUC__
364 	(void)&optbuf;
365 	(void)&name;
366 #endif
367 
368 	if (realpath(name, mntpath) != NULL && stat(mntpath, &sb) == 0) {
369 		if (!S_ISDIR(sb.st_mode)) {
370 			warnx("%s: not a directory", mntpath);
371 			return (1);
372 		}
373 	} else {
374 		warn("%s", mntpath);
375 		return (1);
376 	}
377 
378 	name = mntpath;
379 
380 	if (mntopts == NULL)
381 		mntopts = "";
382 	if (options == NULL) {
383 		if (*mntopts == '\0') {
384 			options = "rw";
385 		} else {
386 			options = mntopts;
387 			mntopts = "";
388 		}
389 	}
390 	optbuf = catopt(strdup(mntopts), options);
391 
392 	if (strcmp(name, "/") == 0)
393 		flags |= MNT_UPDATE;
394 	if (flags & MNT_FORCE)
395 		optbuf = catopt(optbuf, "force");
396 	if (flags & MNT_RDONLY)
397 		optbuf = catopt(optbuf, "ro");
398 	/*
399 	 * XXX
400 	 * The mount_mfs (newfs) command uses -o to select the
401 	 * optimization mode.  We don't pass the default "-o rw"
402 	 * for that reason.
403 	 */
404 	if (flags & MNT_UPDATE)
405 		optbuf = catopt(optbuf, "update");
406 
407 	argc = 0;
408 	argv[argc++] = vfstype;
409 	mangle(optbuf, &argc, argv);
410 	argv[argc++] = spec;
411 	argv[argc++] = name;
412 	argv[argc] = NULL;
413 
414 	if (debug) {
415 		(void)printf("exec: mount_%s", vfstype);
416 		for (i = 1; i < argc; i++)
417 			(void)printf(" %s", argv[i]);
418 		(void)printf("\n");
419 		return (0);
420 	}
421 
422 	switch (pid = fork()) {
423 	case -1:				/* Error. */
424 		warn("fork");
425 		free(optbuf);
426 		return (1);
427 	case 0:					/* Child. */
428 		if (strcmp(vfstype, "ufs") == 0)
429 			exit(mount_ufs(argc, (char * const *) argv));
430 
431 		/* Go find an executable. */
432 		for (edir = edirs; *edir; edir++) {
433 			(void)snprintf(execname,
434 			    sizeof(execname), "%s/mount_%s", *edir, vfstype);
435 			execv(execname, (char * const *)argv);
436 		}
437 		if (errno == ENOENT) {
438 			int len = 0;
439 			char *cp;
440 			for (edir = edirs; *edir; edir++)
441 				len += strlen(*edir) + 2;	/* ", " */
442 			if ((cp = malloc(len)) == NULL)
443 				errx(1, "malloc failed");
444 			cp[0] = '\0';
445 			for (edir = edirs; *edir; edir++) {
446 				strcat(cp, *edir);
447 				if (edir[1] != NULL)
448 					strcat(cp, ", ");
449 			}
450 			warn("exec mount_%s not found in %s", vfstype, cp);
451 		}
452 		exit(1);
453 		/* NOTREACHED */
454 	default:				/* Parent. */
455 		free(optbuf);
456 
457 		if (waitpid(pid, &status, 0) < 0) {
458 			warn("waitpid");
459 			return (1);
460 		}
461 
462 		if (WIFEXITED(status)) {
463 			if (WEXITSTATUS(status) != 0)
464 				return (WEXITSTATUS(status));
465 		} else if (WIFSIGNALED(status)) {
466 			warnx("%s: %s", name, sys_siglist[WTERMSIG(status)]);
467 			return (1);
468 		}
469 
470 		if (verbose) {
471 			if (statfs(name, &sf) < 0) {
472 				warn("statfs %s", name);
473 				return (1);
474 			}
475 			if (fstab_style)
476 				putfsent(&sf);
477 			else
478 				prmount(&sf);
479 		}
480 		break;
481 	}
482 
483 	return (0);
484 }
485 
486 void
487 prmount(sfp)
488 	struct statfs *sfp;
489 {
490 	int flags;
491 	struct opt *o;
492 	struct passwd *pw;
493 	int f;
494 
495 	(void)printf("%s on %s", sfp->f_mntfromname, sfp->f_mntonname);
496 
497 	flags = sfp->f_flags & MNT_VISFLAGMASK;
498 	for (f = 0, o = optnames; flags && o->o_opt; o++)
499 		if (flags & o->o_opt) {
500 			(void)printf("%s%s", !f++ ? " (" : ", ", o->o_name);
501 			flags &= ~o->o_opt;
502 		}
503 	if (sfp->f_owner) {
504 		(void)printf("%smounted by ", !f++ ? " (" : ", ");
505 		if ((pw = getpwuid(sfp->f_owner)) != NULL)
506 			(void)printf("%s", pw->pw_name);
507 		else
508 			(void)printf("%d", sfp->f_owner);
509 	}
510 	if (sfp->f_syncwrites != 0 || sfp->f_asyncwrites != 0)
511 		(void)printf("%swrites: sync %ld async %ld",
512 		    !f++ ? " (" : ", ", sfp->f_syncwrites, sfp->f_asyncwrites);
513 	(void)printf("%s\n", f ? ")" : "");
514 }
515 
516 struct statfs *
517 getmntpt(name)
518 	const char *name;
519 {
520 	struct statfs *mntbuf;
521 	int i, mntsize;
522 
523 	mntsize = getmntinfo(&mntbuf, MNT_NOWAIT);
524 	for (i = 0; i < mntsize; i++)
525 		if (strcmp(mntbuf[i].f_mntfromname, name) == 0 ||
526 		    strcmp(mntbuf[i].f_mntonname, name) == 0)
527 			return (&mntbuf[i]);
528 	return (NULL);
529 }
530 
531 char *
532 catopt(s0, s1)
533 	char *s0;
534 	const char *s1;
535 {
536 	size_t i;
537 	char *cp;
538 
539 	if (s1 == NULL || *s1 == '\0')
540 		return s0;
541 
542 	if (s0 && *s0) {
543 		i = strlen(s0) + strlen(s1) + 1 + 1;
544 		if ((cp = malloc(i)) == NULL)
545 			errx(1, "malloc failed");
546 		(void)snprintf(cp, i, "%s,%s", s0, s1);
547 	} else
548 		cp = strdup(s1);
549 
550 	if (s0)
551 		free(s0);
552 	return (cp);
553 }
554 
555 void
556 mangle(options, argcp, argv)
557 	char *options;
558 	int *argcp;
559 	const char **argv;
560 {
561 	char *p, *s;
562 	int argc;
563 
564 	argc = *argcp;
565 	for (s = options; (p = strsep(&s, ",")) != NULL;)
566 		if (*p != '\0') {
567 			if (*p == '-') {
568 				argv[argc++] = p;
569 				p = strchr(p, '=');
570 				if (p) {
571 					*p = '\0';
572 					argv[argc++] = p+1;
573 				}
574 			} else if (strcmp(p, "rw") != 0) {
575 				argv[argc++] = "-o";
576 				argv[argc++] = p;
577 			}
578 		}
579 
580 	*argcp = argc;
581 }
582 
583 
584 char *
585 update_options(opts, fstab, curflags)
586 	char *opts;
587 	char *fstab;
588 	int curflags;
589 {
590 	char *o, *p;
591 	char *cur;
592 	char *expopt, *newopt, *tmpopt;
593 
594 	if (opts == NULL)
595 		return strdup("");
596 
597 	fstab = strdup(fstab);
598 
599 	/* remove meta options from list */
600 	remopt(fstab, MOUNT_META_OPTION_FSTAB);
601 	remopt(fstab, MOUNT_META_OPTION_CURRENT);
602 	cur = flags2opts(curflags);
603 
604 	/*
605 	 * Expand all meta-options passed to us first.
606 	 */
607 	expopt = NULL;
608 	for (p = opts; (o = strsep(&p, ",")) != NULL;) {
609 		if (strcmp(MOUNT_META_OPTION_FSTAB, o) == 0)
610 			expopt = catopt(expopt, fstab);
611 		else if (strcmp(MOUNT_META_OPTION_CURRENT, o) == 0)
612 			expopt = catopt(expopt, cur);
613 		else
614 			expopt = catopt(expopt, o);
615 	}
616 	free(fstab);
617 	free(cur);
618 	free(opts);
619 
620 	/*
621 	 * Remove previous contradictory arguments. Given option "foo" we
622 	 * remove all the "nofoo" options. Given "nofoo" we remove "nonofoo"
623 	 * and "foo" - so we can deal with possible options like "notice".
624 	 */
625 	newopt = NULL;
626 	for (p = expopt; (o = strsep(&p, ",")) != NULL;) {
627 		if ((tmpopt = malloc( strlen(o) + 2 + 1 )) == NULL)
628 			errx(1, "malloc failed");
629 
630 		strcpy(tmpopt, "no");
631 		strcat(tmpopt, o);
632 		remopt(newopt, tmpopt);
633 		free(tmpopt);
634 
635 		if (strncmp("no", o, 2) == 0)
636 			remopt(newopt, o+2);
637 
638 		newopt = catopt(newopt, o);
639 	}
640 	free(expopt);
641 
642 	return newopt;
643 }
644 
645 void
646 remopt(string, opt)
647 	char *string;
648  	const char *opt;
649 {
650 	char *o, *p, *r;
651 
652 	if (string == NULL || *string == '\0' || opt == NULL || *opt == '\0')
653 		return;
654 
655 	r = string;
656 
657 	for (p = string; (o = strsep(&p, ",")) != NULL;) {
658 		if (strcmp(opt, o) != 0) {
659 			if (*r == ',' && *o != '\0')
660 				r++;
661 			while ((*r++ = *o++) != '\0')
662 			    ;
663 			*--r = ',';
664 		}
665 	}
666 	*r = '\0';
667 }
668 
669 void
670 usage()
671 {
672 
673 	(void)fprintf(stderr, "%s\n%s\n%s\n",
674 "usage: mount [-dfpruvw] [-o options] [-t ufs | external_type] special node",
675 "       mount [-adfpruvw] [-t ufs | external_type]",
676 "       mount [-dfpruvw] special | node");
677 	exit(1);
678 }
679 
680 void
681 putfsent(ent)
682 	const struct statfs *ent;
683 {
684 	struct fstab *fst;
685 	char *opts;
686 
687 	opts = flags2opts(ent->f_flags);
688 	printf("%s\t%s\t%s %s", ent->f_mntfromname, ent->f_mntonname,
689 	    ent->f_fstypename, opts);
690 	free(opts);
691 
692 	if ((fst = getfsspec(ent->f_mntfromname)))
693 		printf("\t%u %u\n", fst->fs_freq, fst->fs_passno);
694 	else if ((fst = getfsfile(ent->f_mntonname)))
695 		printf("\t%u %u\n", fst->fs_freq, fst->fs_passno);
696 	else if (strcmp(ent->f_fstypename, "ufs") == 0)
697 		printf("\t1 1\n");
698 	else
699 		printf("\t0 0\n");
700 }
701 
702 
703 char *
704 flags2opts(flags)
705 	int flags;
706 {
707 	char *res;
708 
709 	res = NULL;
710 
711 	res = catopt(res, (flags & MNT_RDONLY) ? "ro" : "rw");
712 
713 	if (flags & MNT_SYNCHRONOUS)	res = catopt(res, "sync");
714 	if (flags & MNT_NOEXEC)		res = catopt(res, "noexec");
715 	if (flags & MNT_NOSUID)		res = catopt(res, "nosuid");
716 	if (flags & MNT_NODEV)		res = catopt(res, "nodev");
717 	if (flags & MNT_UNION)		res = catopt(res, "union");
718 	if (flags & MNT_ASYNC)		res = catopt(res, "async");
719 	if (flags & MNT_NOATIME)	res = catopt(res, "noatime");
720 	if (flags & MNT_NOCLUSTERR)	res = catopt(res, "noclusterr");
721 	if (flags & MNT_NOCLUSTERW)	res = catopt(res, "noclusterw");
722 	if (flags & MNT_NOSYMFOLLOW)	res = catopt(res, "nosymfollow");
723 	if (flags & MNT_SUIDDIR)	res = catopt(res, "suiddir");
724 
725 	return res;
726 }
727