xref: /freebsd/sbin/umount/umount.c (revision 852ba100814e41898dc6e673fe0af017084e411d)
1 /*-
2  * Copyright (c) 1980, 1989, 1993
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. 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
31 static const char copyright[] =
32 "@(#) Copyright (c) 1980, 1989, 1993\n\
33 	The Regents of the University of California.  All rights reserved.\n";
34 #endif /* not lint */
35 
36 #ifndef lint
37 #if 0
38 static char sccsid[] = "@(#)umount.c	8.8 (Berkeley) 5/8/95";
39 #endif
40 static const char rcsid[] =
41   "$FreeBSD$";
42 #endif /* not lint */
43 
44 #include <sys/param.h>
45 #include <sys/mount.h>
46 #include <sys/socket.h>
47 #include <sys/stat.h>
48 
49 #include <netdb.h>
50 #include <rpc/rpc.h>
51 #include <rpcsvc/mount.h>
52 #include <nfs/nfssvc.h>
53 
54 #include <ctype.h>
55 #include <err.h>
56 #include <errno.h>
57 #include <fstab.h>
58 #include <stdio.h>
59 #include <stdlib.h>
60 #include <string.h>
61 #include <unistd.h>
62 
63 #include "mounttab.h"
64 
65 typedef enum { FIND, REMOVE, CHECKUNIQUE } dowhat;
66 
67 static struct addrinfo *nfshost_ai = NULL;
68 static int	fflag, vflag;
69 static char	*nfshost;
70 
71 struct statfs *checkmntlist(char *);
72 int	 checkvfsname (const char *, char **);
73 struct statfs *getmntentry(const char *fromname, const char *onname,
74 	     fsid_t *fsid, dowhat what);
75 char   **makevfslist (const char *);
76 size_t	 mntinfo (struct statfs **);
77 int	 namematch (struct addrinfo *);
78 int	 parsehexfsid(const char *hex, fsid_t *fsid);
79 int	 sacmp (void *, void *);
80 int	 umountall (char **);
81 int	 checkname (char *, char **);
82 int	 umountfs(struct statfs *sfs);
83 void	 usage (void);
84 int	 xdr_dir (XDR *, char *);
85 
86 int
87 main(int argc, char *argv[])
88 {
89 	int all, errs, ch, mntsize, error, nfsforce, ret;
90 	char **typelist = NULL;
91 	struct statfs *mntbuf, *sfs;
92 	struct addrinfo hints;
93 
94 	nfsforce = all = errs = 0;
95 	while ((ch = getopt(argc, argv, "AaF:fh:Nnt:v")) != -1)
96 		switch (ch) {
97 		case 'A':
98 			all = 2;
99 			break;
100 		case 'a':
101 			all = 1;
102 			break;
103 		case 'F':
104 			setfstab(optarg);
105 			break;
106 		case 'f':
107 			fflag |= MNT_FORCE;
108 			break;
109 		case 'h':	/* -h implies -A. */
110 			all = 2;
111 			nfshost = optarg;
112 			break;
113 		case 'N':
114 			nfsforce = 1;
115 			break;
116 		case 'n':
117 			fflag |= MNT_NONBUSY;
118 			break;
119 		case 't':
120 			if (typelist != NULL)
121 				err(1, "only one -t option may be specified");
122 			typelist = makevfslist(optarg);
123 			break;
124 		case 'v':
125 			vflag = 1;
126 			break;
127 		default:
128 			usage();
129 			/* NOTREACHED */
130 		}
131 	argc -= optind;
132 	argv += optind;
133 
134 	if ((fflag & MNT_FORCE) != 0 && (fflag & MNT_NONBUSY) != 0)
135 		err(1, "-f and -n are mutually exclusive");
136 
137 	/* Start disks transferring immediately. */
138 	if ((fflag & (MNT_FORCE | MNT_NONBUSY)) == 0 && nfsforce == 0)
139 		sync();
140 
141 	if ((argc == 0 && !all) || (argc != 0 && all))
142 		usage();
143 
144 	if (nfsforce != 0 && (argc == 0 || nfshost != NULL || typelist != NULL))
145 		usage();
146 
147 	/* -h implies "-t nfs" if no -t flag. */
148 	if ((nfshost != NULL) && (typelist == NULL))
149 		typelist = makevfslist("nfs");
150 
151 	if (nfshost != NULL) {
152 		memset(&hints, 0, sizeof hints);
153 		error = getaddrinfo(nfshost, NULL, &hints, &nfshost_ai);
154 		if (error)
155 			errx(1, "%s: %s", nfshost, gai_strerror(error));
156 	}
157 
158 	switch (all) {
159 	case 2:
160 		if ((mntsize = mntinfo(&mntbuf)) <= 0)
161 			break;
162 		/*
163 		 * We unmount the nfs-mounts in the reverse order
164 		 * that they were mounted.
165 		 */
166 		for (errs = 0, mntsize--; mntsize > 0; mntsize--) {
167 			sfs = &mntbuf[mntsize];
168 			if (checkvfsname(sfs->f_fstypename, typelist))
169 				continue;
170 			if (strcmp(sfs->f_mntonname, "/dev") == 0)
171 				continue;
172 			if (umountfs(sfs) != 0)
173 				errs = 1;
174 		}
175 		free(mntbuf);
176 		break;
177 	case 1:
178 		if (setfsent() == 0)
179 			err(1, "%s", getfstab());
180 		errs = umountall(typelist);
181 		break;
182 	case 0:
183 		for (errs = 0; *argv != NULL; ++argv)
184 			if (nfsforce != 0) {
185 				/*
186 				 * First do the nfssvc() syscall to shut down
187 				 * the mount point and then do the forced
188 				 * dismount.
189 				 */
190 				ret = nfssvc(NFSSVC_FORCEDISM, *argv);
191 				if (ret >= 0)
192 					ret = unmount(*argv, MNT_FORCE);
193 				if (ret < 0) {
194 					warn("%s", *argv);
195 					errs = 1;
196 				}
197 			} else if (checkname(*argv, typelist) != 0)
198 				errs = 1;
199 		break;
200 	}
201 	exit(errs);
202 }
203 
204 int
205 umountall(char **typelist)
206 {
207 	struct xvfsconf vfc;
208 	struct fstab *fs;
209 	int rval;
210 	char *cp;
211 	static int firstcall = 1;
212 
213 	if ((fs = getfsent()) != NULL)
214 		firstcall = 0;
215 	else if (firstcall)
216 		errx(1, "fstab reading failure");
217 	else
218 		return (0);
219 	do {
220 		/* Ignore the root. */
221 		if (strcmp(fs->fs_file, "/") == 0)
222 			continue;
223 		/*
224 		 * !!!
225 		 * Historic practice: ignore unknown FSTAB_* fields.
226 		 */
227 		if (strcmp(fs->fs_type, FSTAB_RW) &&
228 		    strcmp(fs->fs_type, FSTAB_RO) &&
229 		    strcmp(fs->fs_type, FSTAB_RQ))
230 			continue;
231 		/* Ignore unknown file system types. */
232 		if (getvfsbyname(fs->fs_vfstype, &vfc) == -1)
233 			continue;
234 		if (checkvfsname(fs->fs_vfstype, typelist))
235 			continue;
236 
237 		/*
238 		 * We want to unmount the file systems in the reverse order
239 		 * that they were mounted.  So, we save off the file name
240 		 * in some allocated memory, and then call recursively.
241 		 */
242 		if ((cp = malloc((size_t)strlen(fs->fs_file) + 1)) == NULL)
243 			err(1, "malloc failed");
244 		(void)strcpy(cp, fs->fs_file);
245 		rval = umountall(typelist);
246 		rval = checkname(cp, typelist) || rval;
247 		free(cp);
248 		return (rval);
249 	} while ((fs = getfsent()) != NULL);
250 	return (0);
251 }
252 
253 /*
254  * Do magic checks on mountpoint/device/fsid, and then call unmount(2).
255  */
256 int
257 checkname(char *mntname, char **typelist)
258 {
259 	char buf[MAXPATHLEN];
260 	struct statfs sfsbuf;
261 	struct stat sb;
262 	struct statfs *sfs;
263 	char *delimp;
264 	dev_t dev;
265 	int len;
266 
267 	/*
268 	 * 1. Check if the name exists in the mounttable.
269 	 */
270 	sfs = checkmntlist(mntname);
271 	/*
272 	 * 2. Remove trailing slashes if there are any. After that
273 	 * we look up the name in the mounttable again.
274 	 */
275 	if (sfs == NULL) {
276 		len = strlen(mntname);
277 		while (len > 1 && mntname[len - 1] == '/')
278 			mntname[--len] = '\0';
279 		sfs = checkmntlist(mntname);
280 	}
281 	/*
282 	 * 3. Check if the deprecated NFS syntax with an '@' has been used
283 	 * and translate it to the ':' syntax. Look up the name in the
284 	 * mount table again.
285 	 */
286 	if (sfs == NULL && (delimp = strrchr(mntname, '@')) != NULL) {
287 		snprintf(buf, sizeof(buf), "%s:%.*s", delimp + 1,
288 		    (int)(delimp - mntname), mntname);
289 		len = strlen(buf);
290 		while (len > 1 && buf[len - 1] == '/')
291 			buf[--len] = '\0';
292 		sfs = checkmntlist(buf);
293 	}
294 	/*
295 	 * 4. Resort to a statfs(2) call. This is the last check so that
296 	 * hung NFS filesystems for example can be unmounted without
297 	 * potentially blocking forever in statfs() as long as the
298 	 * filesystem is specified unambiguously. This covers all the
299 	 * hard cases such as symlinks and mismatches between the
300 	 * mount list and reality.
301 	 * We also do this if an ambiguous mount point was specified.
302 	 */
303 	if (sfs == NULL || (getmntentry(NULL, mntname, NULL, FIND) != NULL &&
304 	    getmntentry(NULL, mntname, NULL, CHECKUNIQUE) == NULL)) {
305 		if (statfs(mntname, &sfsbuf) != 0) {
306 			warn("%s: statfs", mntname);
307 		} else if (stat(mntname, &sb) != 0) {
308 			warn("%s: stat", mntname);
309 		} else if (S_ISDIR(sb.st_mode)) {
310 			/* Check that `mntname' is the root directory. */
311 			dev = sb.st_dev;
312 			snprintf(buf, sizeof(buf), "%s/..", mntname);
313 			if (stat(buf, &sb) != 0) {
314 				warn("%s: stat", buf);
315 			} else if (sb.st_dev == dev) {
316 				warnx("%s: not a file system root directory",
317 				    mntname);
318 				return (1);
319 			} else
320 				sfs = &sfsbuf;
321 		}
322 	}
323 	if (sfs == NULL) {
324 		warnx("%s: unknown file system", mntname);
325 		return (1);
326 	}
327 	if (checkvfsname(sfs->f_fstypename, typelist))
328 		return (1);
329 	return (umountfs(sfs));
330 }
331 
332 /*
333  * NFS stuff and unmount(2) call
334  */
335 int
336 umountfs(struct statfs *sfs)
337 {
338 	char fsidbuf[64];
339 	enum clnt_stat clnt_stat;
340 	struct timeval try;
341 	struct addrinfo *ai, hints;
342 	int do_rpc;
343 	CLIENT *clp;
344 	char *nfsdirname, *orignfsdirname;
345 	char *hostp, *delimp;
346 	char buf[1024];
347 	struct nfscl_dumpmntopts dumpmntopts;
348 	const char *proto_ptr = NULL;
349 
350 	ai = NULL;
351 	do_rpc = 0;
352 	hostp = NULL;
353 	nfsdirname = delimp = orignfsdirname = NULL;
354 	memset(&hints, 0, sizeof hints);
355 
356 	if (strcmp(sfs->f_fstypename, "nfs") == 0) {
357 		if ((nfsdirname = strdup(sfs->f_mntfromname)) == NULL)
358 			err(1, "strdup");
359 		orignfsdirname = nfsdirname;
360 		if (*nfsdirname == '[' &&
361 		    (delimp = strchr(nfsdirname + 1, ']')) != NULL &&
362 		    *(delimp + 1) == ':') {
363 			hostp = nfsdirname + 1;
364 			nfsdirname = delimp + 2;
365 		} else if ((delimp = strrchr(nfsdirname, ':')) != NULL) {
366 			hostp = nfsdirname;
367 			nfsdirname = delimp + 1;
368 		}
369 		if (hostp != NULL) {
370 			*delimp = '\0';
371 			getaddrinfo(hostp, NULL, &hints, &ai);
372 			if (ai == NULL) {
373 				warnx("can't get net id for host");
374 			}
375 		}
376 
377 		/*
378 		 * Check if we have to start the rpc-call later.
379 		 * If there are still identical nfs-names mounted,
380 		 * we skip the rpc-call. Obviously this has to
381 		 * happen before unmount(2), but it should happen
382 		 * after the previous namecheck.
383 		 * A non-NULL return means that this is the last
384 		 * mount from mntfromname that is still mounted.
385 		 */
386 		if (getmntentry(sfs->f_mntfromname, NULL, NULL,
387 		    CHECKUNIQUE) != NULL) {
388 			do_rpc = 1;
389 			proto_ptr = "udp";
390 			/*
391 			 * Try and find out whether this NFS mount is NFSv4 and
392 			 * what protocol is being used. If this fails, the
393 			 * default is NFSv2,3 and use UDP for the Unmount RPC.
394 			 */
395 			dumpmntopts.ndmnt_fname = sfs->f_mntonname;
396 			dumpmntopts.ndmnt_buf = buf;
397 			dumpmntopts.ndmnt_blen = sizeof(buf);
398 			if (nfssvc(NFSSVC_DUMPMNTOPTS, &dumpmntopts) >= 0) {
399 				if (strstr(buf, "nfsv4,") != NULL)
400 					do_rpc = 0;
401 				else if (strstr(buf, ",tcp,") != NULL)
402 					proto_ptr = "tcp";
403 			}
404 		}
405 	}
406 
407 	if (!namematch(ai)) {
408 		free(orignfsdirname);
409 		return (1);
410 	}
411 	/* First try to unmount using the file system ID. */
412 	snprintf(fsidbuf, sizeof(fsidbuf), "FSID:%d:%d", sfs->f_fsid.val[0],
413 	    sfs->f_fsid.val[1]);
414 	if (unmount(fsidbuf, fflag | MNT_BYFSID) != 0) {
415 		/* XXX, non-root users get a zero fsid, so don't warn. */
416 		if (errno != ENOENT || sfs->f_fsid.val[0] != 0 ||
417 		    sfs->f_fsid.val[1] != 0)
418 			warn("unmount of %s failed", sfs->f_mntonname);
419 		if (errno != ENOENT) {
420 			free(orignfsdirname);
421 			return (1);
422 		}
423 		/* Compatibility for old kernels. */
424 		if (sfs->f_fsid.val[0] != 0 || sfs->f_fsid.val[1] != 0)
425 			warnx("retrying using path instead of file system ID");
426 		if (unmount(sfs->f_mntonname, fflag) != 0) {
427 			warn("unmount of %s failed", sfs->f_mntonname);
428 			free(orignfsdirname);
429 			return (1);
430 		}
431 	}
432 	/* Mark this this file system as unmounted. */
433 	getmntentry(NULL, NULL, &sfs->f_fsid, REMOVE);
434 	if (vflag)
435 		(void)printf("%s: unmount from %s\n", sfs->f_mntfromname,
436 		    sfs->f_mntonname);
437 	/*
438 	 * Report to mountd-server which nfsname
439 	 * has been unmounted.
440 	 */
441 	if (ai != NULL && !(fflag & MNT_FORCE) && do_rpc) {
442 		clp = clnt_create(hostp, MOUNTPROG, MOUNTVERS3, proto_ptr);
443 		if (clp  == NULL) {
444 			warnx("%s: %s", hostp,
445 			    clnt_spcreateerror("MOUNTPROG"));
446 			free(orignfsdirname);
447 			return (1);
448 		}
449 		clp->cl_auth = authsys_create_default();
450 		try.tv_sec = 20;
451 		try.tv_usec = 0;
452 		clnt_stat = clnt_call(clp, MOUNTPROC_UMNT, (xdrproc_t)xdr_dir,
453 		    nfsdirname, (xdrproc_t)xdr_void, (caddr_t)0, try);
454 		if (clnt_stat != RPC_SUCCESS) {
455 			warnx("%s: %s", hostp,
456 			    clnt_sperror(clp, "RPCMNT_UMOUNT"));
457 			free(orignfsdirname);
458 			return (1);
459 		}
460 		/*
461 		 * Remove the unmounted entry from /var/db/mounttab.
462 		 */
463 		if (read_mtab()) {
464 			clean_mtab(hostp, nfsdirname, vflag);
465 			if(!write_mtab(vflag))
466 				warnx("cannot remove mounttab entry %s:%s",
467 				    hostp, nfsdirname);
468 			free_mtab();
469 		}
470 		auth_destroy(clp->cl_auth);
471 		clnt_destroy(clp);
472 	}
473 	free(orignfsdirname);
474 	return (0);
475 }
476 
477 struct statfs *
478 getmntentry(const char *fromname, const char *onname, fsid_t *fsid, dowhat what)
479 {
480 	static struct statfs *mntbuf;
481 	static size_t mntsize = 0;
482 	static int *mntcheck = NULL;
483 	struct statfs *sfs, *foundsfs;
484 	int i, count;
485 
486 	if (mntsize <= 0) {
487 		if ((mntsize = mntinfo(&mntbuf)) <= 0)
488 			return (NULL);
489 	}
490 	if (mntcheck == NULL) {
491 		if ((mntcheck = calloc(mntsize + 1, sizeof(int))) == NULL)
492 			err(1, "calloc");
493 	}
494 	/*
495 	 * We want to get the file systems in the reverse order
496 	 * that they were mounted. Unmounted file systems are marked
497 	 * in a table called 'mntcheck'.
498 	 */
499 	count = 0;
500 	foundsfs = NULL;
501 	for (i = mntsize - 1; i >= 0; i--) {
502 		if (mntcheck[i])
503 			continue;
504 		sfs = &mntbuf[i];
505 		if (fromname != NULL && strcmp(sfs->f_mntfromname,
506 		    fromname) != 0)
507 			continue;
508 		if (onname != NULL && strcmp(sfs->f_mntonname, onname) != 0)
509 			continue;
510 		if (fsid != NULL && bcmp(&sfs->f_fsid, fsid,
511 		    sizeof(*fsid)) != 0)
512 			continue;
513 
514 		switch (what) {
515 		case CHECKUNIQUE:
516 			foundsfs = sfs;
517 			count++;
518 			continue;
519 		case REMOVE:
520 			mntcheck[i] = 1;
521 			break;
522 		default:
523 			break;
524 		}
525 		return (sfs);
526 	}
527 
528 	if (what == CHECKUNIQUE && count == 1)
529 		return (foundsfs);
530 	return (NULL);
531 }
532 
533 int
534 sacmp(void *sa1, void *sa2)
535 {
536 	void *p1, *p2;
537 	int len;
538 
539 	if (((struct sockaddr *)sa1)->sa_family !=
540 	    ((struct sockaddr *)sa2)->sa_family)
541 		return (1);
542 
543 	switch (((struct sockaddr *)sa1)->sa_family) {
544 	case AF_INET:
545 		p1 = &((struct sockaddr_in *)sa1)->sin_addr;
546 		p2 = &((struct sockaddr_in *)sa2)->sin_addr;
547 		len = 4;
548 		break;
549 	case AF_INET6:
550 		p1 = &((struct sockaddr_in6 *)sa1)->sin6_addr;
551 		p2 = &((struct sockaddr_in6 *)sa2)->sin6_addr;
552 		len = 16;
553 		if (((struct sockaddr_in6 *)sa1)->sin6_scope_id !=
554 		    ((struct sockaddr_in6 *)sa2)->sin6_scope_id)
555 			return (1);
556 		break;
557 	default:
558 		return (1);
559 	}
560 
561 	return memcmp(p1, p2, len);
562 }
563 
564 int
565 namematch(struct addrinfo *ai)
566 {
567 	struct addrinfo *aip;
568 
569 	if (nfshost == NULL || nfshost_ai == NULL)
570 		return (1);
571 
572 	while (ai != NULL) {
573 		aip = nfshost_ai;
574 		while (aip != NULL) {
575 			if (sacmp(ai->ai_addr, aip->ai_addr) == 0)
576 				return (1);
577 			aip = aip->ai_next;
578 		}
579 		ai = ai->ai_next;
580 	}
581 
582 	return (0);
583 }
584 
585 struct statfs *
586 checkmntlist(char *mntname)
587 {
588 	struct statfs *sfs;
589 	fsid_t fsid;
590 
591 	sfs = NULL;
592 	if (parsehexfsid(mntname, &fsid) == 0)
593 		sfs = getmntentry(NULL, NULL, &fsid, FIND);
594 	if (sfs == NULL)
595 		sfs = getmntentry(NULL, mntname, NULL, FIND);
596 	if (sfs == NULL)
597 		sfs = getmntentry(mntname, NULL, NULL, FIND);
598 	return (sfs);
599 }
600 
601 size_t
602 mntinfo(struct statfs **mntbuf)
603 {
604 	static struct statfs *origbuf;
605 	size_t bufsize;
606 	int mntsize;
607 
608 	mntsize = getfsstat(NULL, 0, MNT_NOWAIT);
609 	if (mntsize <= 0)
610 		return (0);
611 	bufsize = (mntsize + 1) * sizeof(struct statfs);
612 	if ((origbuf = malloc(bufsize)) == NULL)
613 		err(1, "malloc");
614 	mntsize = getfsstat(origbuf, (long)bufsize, MNT_NOWAIT);
615 	*mntbuf = origbuf;
616 	return (mntsize);
617 }
618 
619 /*
620  * Convert a hexadecimal filesystem ID to an fsid_t.
621  * Returns 0 on success.
622  */
623 int
624 parsehexfsid(const char *hex, fsid_t *fsid)
625 {
626 	char hexbuf[3];
627 	int i;
628 
629 	if (strlen(hex) != sizeof(*fsid) * 2)
630 		return (-1);
631 	hexbuf[2] = '\0';
632 	for (i = 0; i < (int)sizeof(*fsid); i++) {
633 		hexbuf[0] = hex[i * 2];
634 		hexbuf[1] = hex[i * 2 + 1];
635 		if (!isxdigit(hexbuf[0]) || !isxdigit(hexbuf[1]))
636 			return (-1);
637 		((u_char *)fsid)[i] = strtol(hexbuf, NULL, 16);
638 	}
639 	return (0);
640 }
641 
642 /*
643  * xdr routines for mount rpc's
644  */
645 int
646 xdr_dir(XDR *xdrsp, char *dirp)
647 {
648 
649 	return (xdr_string(xdrsp, &dirp, MNTPATHLEN));
650 }
651 
652 void
653 usage(void)
654 {
655 
656 	(void)fprintf(stderr, "%s\n%s\n",
657 	    "usage: umount [-fNnv] special ... | node ... | fsid ...",
658 	    "       umount -a | -A [-F fstab] [-fnv] [-h host] [-t type]");
659 	exit(1);
660 }
661