mount.c revision 128658 
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 * 4. Neither the name of the University nor the names of its contributors
14 *    may be used to endorse or promote products derived from this software
15 *    without specific prior written permission.
16 *
17 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
18 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
19 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
20 * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
21 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
22 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
23 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
24 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
25 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
26 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
27 * SUCH DAMAGE.
28 */
29
30#ifndef lint
31static const char copyright[] =
32"@(#) Copyright (c) 1980, 1989, 1993, 1994\n\
33	The Regents of the University of California.  All rights reserved.\n";
34#endif /* not lint */
35
36#ifndef lint
37#if 0
38static char sccsid[] = "@(#)mount.c	8.25 (Berkeley) 5/8/95";
39#endif
40static const char rcsid[] =
41  "$FreeBSD: head/sbin/mount/mount.c 128658 2004-04-26 15:13:46Z bmilekic $";
42#endif /* not lint */
43
44#include <sys/param.h>
45#include <sys/mount.h>
46#include <sys/stat.h>
47#include <sys/wait.h>
48
49#include <ctype.h>
50#include <err.h>
51#include <errno.h>
52#include <fstab.h>
53#include <paths.h>
54#include <pwd.h>
55#include <signal.h>
56#include <stdint.h>
57#include <stdio.h>
58#include <stdlib.h>
59#include <string.h>
60#include <unistd.h>
61
62#include "extern.h"
63#include "mntopts.h"
64#include "pathnames.h"
65
66/* `meta' options */
67#define MOUNT_META_OPTION_FSTAB		"fstab"
68#define MOUNT_META_OPTION_CURRENT	"current"
69
70int debug, fstab_style, verbose;
71
72char   *catopt(char *, const char *);
73struct statfs *getmntpt(const char *);
74int	hasopt(const char *, const char *);
75int	ismounted(struct fstab *, struct statfs *, int);
76int	isremountable(const char *);
77void	mangle(char *, int *, const char **);
78char   *update_options(char *, char *, int);
79int	mountfs(const char *, const char *, const char *,
80			int, const char *, const char *);
81void	remopt(char *, const char *);
82void	prmount(struct statfs *);
83void	putfsent(const struct statfs *);
84void	usage(void);
85char   *flags2opts(int);
86
87/* Map from mount options to printable formats. */
88static struct opt {
89	int o_opt;
90	const char *o_name;
91} optnames[] = {
92	{ MNT_ASYNC,		"asynchronous" },
93	{ MNT_EXPORTED,		"NFS exported" },
94	{ MNT_LOCAL,		"local" },
95	{ MNT_NOATIME,		"noatime" },
96	{ MNT_NODEV,		"nodev" },
97	{ MNT_NOEXEC,		"noexec" },
98	{ MNT_NOSUID,		"nosuid" },
99	{ MNT_NOSYMFOLLOW,	"nosymfollow" },
100	{ MNT_QUOTA,		"with quotas" },
101	{ MNT_RDONLY,		"read-only" },
102	{ MNT_SYNCHRONOUS,	"synchronous" },
103	{ MNT_UNION,		"union" },
104	{ MNT_NOCLUSTERR,	"noclusterr" },
105	{ MNT_NOCLUSTERW,	"noclusterw" },
106	{ MNT_SUIDDIR,		"suiddir" },
107	{ MNT_SOFTDEP,		"soft-updates" },
108	{ MNT_MULTILABEL,	"multilabel" },
109	{ MNT_ACLS,		"acls" },
110	{ 0, NULL }
111};
112
113/*
114 * List of VFS types that can be remounted without becoming mounted on top
115 * of each other.
116 * XXX Is this list correct?
117 */
118static const char *
119remountable_fs_names[] = {
120	"ufs", "ffs", "ext2fs",
121	0
122};
123
124int
125main(argc, argv)
126	int argc;
127	char * const argv[];
128{
129	const char *mntfromname, **vfslist, *vfstype;
130	struct fstab *fs;
131	struct statfs *mntbuf;
132	FILE *mountdfp;
133	pid_t pid;
134	int all, ch, i, init_flags, mntsize, rval, have_fstab;
135	char *cp, *ep, *options;
136
137	all = init_flags = 0;
138	options = NULL;
139	vfslist = NULL;
140	vfstype = "ufs";
141	while ((ch = getopt(argc, argv, "adF:fo:prwt:uv")) != -1)
142		switch (ch) {
143		case 'a':
144			all = 1;
145			break;
146		case 'd':
147			debug = 1;
148			break;
149		case 'F':
150			setfstab(optarg);
151			break;
152		case 'f':
153			init_flags |= MNT_FORCE;
154			break;
155		case 'o':
156			if (*optarg)
157				options = catopt(options, optarg);
158			break;
159		case 'p':
160			fstab_style = 1;
161			verbose = 1;
162			break;
163		case 'r':
164			options = catopt(options, "ro");
165			break;
166		case 't':
167			if (vfslist != NULL)
168				errx(1, "only one -t option may be specified");
169			vfslist = makevfslist(optarg);
170			vfstype = optarg;
171			break;
172		case 'u':
173			init_flags |= MNT_UPDATE;
174			break;
175		case 'v':
176			verbose = 1;
177			break;
178		case 'w':
179			options = catopt(options, "noro");
180			break;
181		case '?':
182		default:
183			usage();
184			/* NOTREACHED */
185		}
186	argc -= optind;
187	argv += optind;
188
189#define	BADTYPE(type)							\
190	(strcmp(type, FSTAB_RO) &&					\
191	    strcmp(type, FSTAB_RW) && strcmp(type, FSTAB_RQ))
192
193	rval = 0;
194	switch (argc) {
195	case 0:
196		if ((mntsize = getmntinfo(&mntbuf, MNT_NOWAIT)) == 0)
197			err(1, "getmntinfo");
198		if (all) {
199			while ((fs = getfsent()) != NULL) {
200				if (BADTYPE(fs->fs_type))
201					continue;
202				if (checkvfsname(fs->fs_vfstype, vfslist))
203					continue;
204				if (hasopt(fs->fs_mntops, "noauto"))
205					continue;
206				if (!(init_flags & MNT_UPDATE) &&
207				    ismounted(fs, mntbuf, mntsize))
208					continue;
209				options = update_options(options, fs->fs_mntops,
210				    mntbuf->f_flags);
211				if (mountfs(fs->fs_vfstype, fs->fs_spec,
212				    fs->fs_file, init_flags, options,
213				    fs->fs_mntops))
214					rval = 1;
215			}
216		} else if (fstab_style) {
217			for (i = 0; i < mntsize; i++) {
218				if (checkvfsname(mntbuf[i].f_fstypename, vfslist))
219					continue;
220				putfsent(&mntbuf[i]);
221			}
222		} else {
223			for (i = 0; i < mntsize; i++) {
224				if (checkvfsname(mntbuf[i].f_fstypename,
225				    vfslist))
226					continue;
227				prmount(&mntbuf[i]);
228			}
229		}
230		exit(rval);
231	case 1:
232		if (vfslist != NULL)
233			usage();
234
235		rmslashes(*argv, *argv);
236		if (init_flags & MNT_UPDATE) {
237			mntfromname = NULL;
238			have_fstab = 0;
239			if ((mntbuf = getmntpt(*argv)) == NULL)
240				errx(1, "not currently mounted %s", *argv);
241			/*
242			 * Only get the mntflags from fstab if both mntpoint
243			 * and mntspec are identical. Also handle the special
244			 * case where just '/' is mounted and 'spec' is not
245			 * identical with the one from fstab ('/dev' is missing
246			 * in the spec-string at boot-time).
247			 */
248			if ((fs = getfsfile(mntbuf->f_mntonname)) != NULL) {
249				if (strcmp(fs->fs_spec,
250				    mntbuf->f_mntfromname) == 0 &&
251				    strcmp(fs->fs_file,
252				    mntbuf->f_mntonname) == 0) {
253					have_fstab = 1;
254					mntfromname = mntbuf->f_mntfromname;
255				} else if (argv[0][0] == '/' &&
256				    argv[0][1] == '\0') {
257					fs = getfsfile("/");
258					have_fstab = 1;
259					mntfromname = fs->fs_spec;
260				}
261			}
262			if (have_fstab) {
263				options = update_options(options, fs->fs_mntops,
264				    mntbuf->f_flags);
265			} else {
266				mntfromname = mntbuf->f_mntfromname;
267				options = update_options(options, NULL,
268				    mntbuf->f_flags);
269			}
270			rval = mountfs(mntbuf->f_fstypename, mntfromname,
271			    mntbuf->f_mntonname, init_flags, options, 0);
272			break;
273		}
274		if ((fs = getfsfile(*argv)) == NULL &&
275		    (fs = getfsspec(*argv)) == NULL)
276			errx(1, "%s: unknown special file or file system",
277			    *argv);
278		if (BADTYPE(fs->fs_type))
279			errx(1, "%s has unknown file system type",
280			    *argv);
281		rval = mountfs(fs->fs_vfstype, fs->fs_spec, fs->fs_file,
282		    init_flags, options, fs->fs_mntops);
283		break;
284	case 2:
285		/*
286		 * If -t flag has not been specified, the path cannot be
287		 * found, spec contains either a ':' or a '@', then assume
288		 * that an NFS file system is being specified ala Sun.
289		 * Check if the hostname contains only allowed characters
290		 * to reduce false positives.  IPv6 addresses containing
291		 * ':' will be correctly parsed only if the separator is '@'.
292		 * The definition of a valid hostname is taken from RFC 1034.
293		 */
294		if (vfslist == NULL && ((ep = strchr(argv[0], '@')) != NULL ||
295		    (ep = strchr(argv[0], ':')) != NULL)) {
296			if (*ep == '@') {
297				cp = ep + 1;
298				ep = cp + strlen(cp);
299			} else
300				cp = argv[0];
301			while (cp != ep) {
302				if (!isdigit(*cp) && !isalpha(*cp) &&
303				    *cp != '.' && *cp != '-' && *cp != ':')
304					break;
305				cp++;
306			}
307			if (cp == ep)
308				vfstype = "nfs";
309		}
310		rval = mountfs(vfstype,
311		    argv[0], argv[1], init_flags, options, NULL);
312		break;
313	default:
314		usage();
315		/* NOTREACHED */
316	}
317
318	/*
319	 * If the mount was successfully, and done by root, tell mountd the
320	 * good news.  Pid checks are probably unnecessary, but don't hurt.
321	 */
322	if (rval == 0 && getuid() == 0 &&
323	    (mountdfp = fopen(_PATH_MOUNTDPID, "r")) != NULL) {
324		if (fscanf(mountdfp, "%d", &pid) == 1 &&
325		     pid > 0 && kill(pid, SIGHUP) == -1 && errno != ESRCH)
326			err(1, "signal mountd");
327		(void)fclose(mountdfp);
328	}
329
330	exit(rval);
331}
332
333int
334ismounted(fs, mntbuf, mntsize)
335	struct fstab *fs;
336	struct statfs *mntbuf;
337	int mntsize;
338{
339	int i;
340
341	if (fs->fs_file[0] == '/' && fs->fs_file[1] == '\0')
342		/* the root file system can always be remounted */
343		return (0);
344
345	for (i = mntsize - 1; i >= 0; --i)
346		if (strcmp(fs->fs_file, mntbuf[i].f_mntonname) == 0 &&
347		    (!isremountable(fs->fs_vfstype) ||
348		     strcmp(fs->fs_spec, mntbuf[i].f_mntfromname) == 0))
349			return (1);
350	return (0);
351}
352
353int
354isremountable(vfsname)
355	const char *vfsname;
356{
357	const char **cp;
358
359	for (cp = remountable_fs_names; *cp; cp++)
360		if (strcmp(*cp, vfsname) == 0)
361			return (1);
362	return (0);
363}
364
365int
366hasopt(mntopts, option)
367	const char *mntopts, *option;
368{
369	int negative, found;
370	char *opt, *optbuf;
371
372	if (option[0] == 'n' && option[1] == 'o') {
373		negative = 1;
374		option += 2;
375	} else
376		negative = 0;
377	optbuf = strdup(mntopts);
378	found = 0;
379	for (opt = optbuf; (opt = strtok(opt, ",")) != NULL; opt = NULL) {
380		if (opt[0] == 'n' && opt[1] == 'o') {
381			if (!strcasecmp(opt + 2, option))
382				found = negative;
383		} else if (!strcasecmp(opt, option))
384			found = !negative;
385	}
386	free(optbuf);
387	return (found);
388}
389
390int
391mountfs(vfstype, spec, name, flags, options, mntopts)
392	const char *vfstype, *spec, *name, *options, *mntopts;
393	int flags;
394{
395	const char *argv[100];
396	struct statfs sf;
397	pid_t pid;
398	int argc, i, status;
399	char *optbuf, execname[PATH_MAX], mntpath[PATH_MAX];
400
401#if __GNUC__
402	(void)&optbuf;
403	(void)&name;
404#endif
405
406	/* resolve the mountpoint with realpath(3) */
407	(void)checkpath(name, mntpath);
408	name = mntpath;
409
410	if (mntopts == NULL)
411		mntopts = "";
412	if (options == NULL) {
413		if (*mntopts == '\0') {
414			options = "rw";
415		} else {
416			options = mntopts;
417			mntopts = "";
418		}
419	}
420	optbuf = catopt(strdup(mntopts), options);
421
422	if (strcmp(name, "/") == 0)
423		flags |= MNT_UPDATE;
424	if (flags & MNT_FORCE)
425		optbuf = catopt(optbuf, "force");
426	if (flags & MNT_RDONLY)
427		optbuf = catopt(optbuf, "ro");
428	/*
429	 * XXX
430	 * The mount_mfs (newfs) command uses -o to select the
431	 * optimization mode.  We don't pass the default "-o rw"
432	 * for that reason.
433	 */
434	if (flags & MNT_UPDATE)
435		optbuf = catopt(optbuf, "update");
436
437	/* Compatibility glue. */
438	if (strcmp(vfstype, "msdos") == 0)
439		vfstype = "msdosfs";
440
441	argc = 0;
442	argv[argc++] = vfstype;
443	mangle(optbuf, &argc, argv);
444	argv[argc++] = spec;
445	argv[argc++] = name;
446	argv[argc] = NULL;
447
448	if (debug) {
449		(void)printf("exec: mount_%s", vfstype);
450		for (i = 1; i < argc; i++)
451			(void)printf(" %s", argv[i]);
452		(void)printf("\n");
453		return (0);
454	}
455
456	switch (pid = fork()) {
457	case -1:				/* Error. */
458		warn("fork");
459		free(optbuf);
460		return (1);
461	case 0:					/* Child. */
462		if (strcmp(vfstype, "ufs") == 0)
463			exit(mount_ufs(argc, (char * const *) argv));
464
465		/* Go find an executable. */
466		(void)snprintf(execname, sizeof(execname), "mount_%s", vfstype);
467		execvP(execname, _PATH_SYSPATH, (char * const *)argv);
468		if (errno == ENOENT) {
469			warn("exec mount_%s not found in %s", vfstype,
470			    _PATH_SYSPATH);
471		}
472		exit(1);
473		/* NOTREACHED */
474	default:				/* Parent. */
475		free(optbuf);
476
477		if (waitpid(pid, &status, 0) < 0) {
478			warn("waitpid");
479			return (1);
480		}
481
482		if (WIFEXITED(status)) {
483			if (WEXITSTATUS(status) != 0)
484				return (WEXITSTATUS(status));
485		} else if (WIFSIGNALED(status)) {
486			warnx("%s: %s", name, sys_siglist[WTERMSIG(status)]);
487			return (1);
488		}
489
490		if (verbose) {
491			if (statfs(name, &sf) < 0) {
492				warn("statfs %s", name);
493				return (1);
494			}
495			if (fstab_style)
496				putfsent(&sf);
497			else
498				prmount(&sf);
499		}
500		break;
501	}
502
503	return (0);
504}
505
506void
507prmount(sfp)
508	struct statfs *sfp;
509{
510	int flags, i;
511	struct opt *o;
512	struct passwd *pw;
513
514	(void)printf("%s on %s (%s", sfp->f_mntfromname, sfp->f_mntonname,
515	    sfp->f_fstypename);
516
517	flags = sfp->f_flags & MNT_VISFLAGMASK;
518	for (o = optnames; flags && o->o_opt; o++)
519		if (flags & o->o_opt) {
520			(void)printf(", %s", o->o_name);
521			flags &= ~o->o_opt;
522		}
523	/*
524	 * Inform when file system is mounted by an unprivileged user
525	 * or privileged non-root user.
526	 */
527	if ((flags & MNT_USER) != 0 || sfp->f_owner != 0) {
528		(void)printf(", mounted by ");
529		if ((pw = getpwuid(sfp->f_owner)) != NULL)
530			(void)printf("%s", pw->pw_name);
531		else
532			(void)printf("%d", sfp->f_owner);
533	}
534	if (verbose) {
535		if (sfp->f_syncwrites != 0 || sfp->f_asyncwrites != 0)
536			(void)printf(", writes: sync %ju async %ju",
537			    (uintmax_t)sfp->f_syncwrites,
538			    (uintmax_t)sfp->f_asyncwrites);
539		if (sfp->f_syncreads != 0 || sfp->f_asyncreads != 0)
540			(void)printf(", reads: sync %ju async %ju",
541			    (uintmax_t)sfp->f_syncreads,
542			    (uintmax_t)sfp->f_asyncreads);
543		if (sfp->f_fsid.val[0] != 0 || sfp->f_fsid.val[1] != 0) {
544			printf(", fsid ");
545			for (i = 0; i < sizeof(sfp->f_fsid); i++)
546				printf("%02x", ((u_char *)&sfp->f_fsid)[i]);
547		}
548	}
549	(void)printf(")\n");
550}
551
552struct statfs *
553getmntpt(name)
554	const char *name;
555{
556	struct statfs *mntbuf;
557	int i, mntsize;
558
559	mntsize = getmntinfo(&mntbuf, MNT_NOWAIT);
560	for (i = mntsize - 1; i >= 0; i--) {
561		if (strcmp(mntbuf[i].f_mntfromname, name) == 0 ||
562		    strcmp(mntbuf[i].f_mntonname, name) == 0)
563			return (&mntbuf[i]);
564	}
565	return (NULL);
566}
567
568char *
569catopt(s0, s1)
570	char *s0;
571	const char *s1;
572{
573	size_t i;
574	char *cp;
575
576	if (s1 == NULL || *s1 == '\0')
577		return s0;
578
579	if (s0 && *s0) {
580		i = strlen(s0) + strlen(s1) + 1 + 1;
581		if ((cp = malloc(i)) == NULL)
582			errx(1, "malloc failed");
583		(void)snprintf(cp, i, "%s,%s", s0, s1);
584	} else
585		cp = strdup(s1);
586
587	if (s0)
588		free(s0);
589	return (cp);
590}
591
592void
593mangle(options, argcp, argv)
594	char *options;
595	int *argcp;
596	const char **argv;
597{
598	char *p, *s;
599	int argc;
600
601	argc = *argcp;
602	for (s = options; (p = strsep(&s, ",")) != NULL;)
603		if (*p != '\0') {
604			if (*p == '-') {
605				argv[argc++] = p;
606				p = strchr(p, '=');
607				if (p != NULL) {
608					*p = '\0';
609					argv[argc++] = p+1;
610				}
611			} else if (strcmp(p, "rw") != 0) {
612				argv[argc++] = "-o";
613				argv[argc++] = p;
614			}
615		}
616
617	*argcp = argc;
618}
619
620
621char *
622update_options(opts, fstab, curflags)
623	char *opts;
624	char *fstab;
625	int curflags;
626{
627	char *o, *p;
628	char *cur;
629	char *expopt, *newopt, *tmpopt;
630
631	if (opts == NULL)
632		return strdup("");
633
634	/* remove meta options from list */
635	remopt(fstab, MOUNT_META_OPTION_FSTAB);
636	remopt(fstab, MOUNT_META_OPTION_CURRENT);
637	cur = flags2opts(curflags);
638
639	/*
640	 * Expand all meta-options passed to us first.
641	 */
642	expopt = NULL;
643	for (p = opts; (o = strsep(&p, ",")) != NULL;) {
644		if (strcmp(MOUNT_META_OPTION_FSTAB, o) == 0)
645			expopt = catopt(expopt, fstab);
646		else if (strcmp(MOUNT_META_OPTION_CURRENT, o) == 0)
647			expopt = catopt(expopt, cur);
648		else
649			expopt = catopt(expopt, o);
650	}
651	free(cur);
652	free(opts);
653
654	/*
655	 * Remove previous contradictory arguments. Given option "foo" we
656	 * remove all the "nofoo" options. Given "nofoo" we remove "nonofoo"
657	 * and "foo" - so we can deal with possible options like "notice".
658	 */
659	newopt = NULL;
660	for (p = expopt; (o = strsep(&p, ",")) != NULL;) {
661		if ((tmpopt = malloc( strlen(o) + 2 + 1 )) == NULL)
662			errx(1, "malloc failed");
663
664		strcpy(tmpopt, "no");
665		strcat(tmpopt, o);
666		remopt(newopt, tmpopt);
667		free(tmpopt);
668
669		if (strncmp("no", o, 2) == 0)
670			remopt(newopt, o+2);
671
672		newopt = catopt(newopt, o);
673	}
674	free(expopt);
675
676	return newopt;
677}
678
679void
680remopt(string, opt)
681	char *string;
682 	const char *opt;
683{
684	char *o, *p, *r;
685
686	if (string == NULL || *string == '\0' || opt == NULL || *opt == '\0')
687		return;
688
689	r = string;
690
691	for (p = string; (o = strsep(&p, ",")) != NULL;) {
692		if (strcmp(opt, o) != 0) {
693			if (*r == ',' && *o != '\0')
694				r++;
695			while ((*r++ = *o++) != '\0')
696			    ;
697			*--r = ',';
698		}
699	}
700	*r = '\0';
701}
702
703void
704usage()
705{
706
707	(void)fprintf(stderr, "%s\n%s\n%s\n",
708"usage: mount [-dfpruvw] [-o options] [-t ufs | external_type] special node",
709"       mount [-adfpruvw] [ -F fstab] [-o options] [-t ufs | external_type]",
710"       mount [-dfpruvw] special | node");
711	exit(1);
712}
713
714void
715putfsent(ent)
716	const struct statfs *ent;
717{
718	struct fstab *fst;
719	char *opts;
720
721	opts = flags2opts(ent->f_flags);
722	printf("%s\t%s\t%s %s", ent->f_mntfromname, ent->f_mntonname,
723	    ent->f_fstypename, opts);
724	free(opts);
725
726	if ((fst = getfsspec(ent->f_mntfromname)))
727		printf("\t%u %u\n", fst->fs_freq, fst->fs_passno);
728	else if ((fst = getfsfile(ent->f_mntonname)))
729		printf("\t%u %u\n", fst->fs_freq, fst->fs_passno);
730	else if (strcmp(ent->f_fstypename, "ufs") == 0) {
731		if (strcmp(ent->f_mntonname, "/") == 0)
732			printf("\t1 1\n");
733		else
734			printf("\t2 2\n");
735	} else
736		printf("\t0 0\n");
737}
738
739
740char *
741flags2opts(flags)
742	int flags;
743{
744	char *res;
745
746	res = NULL;
747
748	res = catopt(res, (flags & MNT_RDONLY) ? "ro" : "rw");
749
750	if (flags & MNT_SYNCHRONOUS)	res = catopt(res, "sync");
751	if (flags & MNT_NOEXEC)		res = catopt(res, "noexec");
752	if (flags & MNT_NOSUID)		res = catopt(res, "nosuid");
753	if (flags & MNT_NODEV)		res = catopt(res, "nodev");
754	if (flags & MNT_UNION)		res = catopt(res, "union");
755	if (flags & MNT_ASYNC)		res = catopt(res, "async");
756	if (flags & MNT_NOATIME)	res = catopt(res, "noatime");
757	if (flags & MNT_NOCLUSTERR)	res = catopt(res, "noclusterr");
758	if (flags & MNT_NOCLUSTERW)	res = catopt(res, "noclusterw");
759	if (flags & MNT_NOSYMFOLLOW)	res = catopt(res, "nosymfollow");
760	if (flags & MNT_SUIDDIR)	res = catopt(res, "suiddir");
761	if (flags & MNT_MULTILABEL)	res = catopt(res, "multilabel");
762	if (flags & MNT_ACLS)		res = catopt(res, "acls");
763
764	return res;
765}
766