xref: /freebsd/sbin/umount/umount.c (revision 2008043f386721d58158e37e0d7e50df8095942d)
1 /*-
2  * SPDX-License-Identifier: BSD-3-Clause
3  *
4  * Copyright (c) 1980, 1989, 1993
5  *	The Regents of the University of California.  All rights reserved.
6  *
7  * Redistribution and use in source and binary forms, with or without
8  * modification, are permitted provided that the following conditions
9  * are met:
10  * 1. Redistributions of source code must retain the above copyright
11  *    notice, this list of conditions and the following disclaimer.
12  * 2. Redistributions in binary form must reproduce the above copyright
13  *    notice, this list of conditions and the following disclaimer in the
14  *    documentation and/or other materials provided with the distribution.
15  * 3. Neither the name of the University nor the names of its contributors
16  *    may be used to endorse or promote products derived from this software
17  *    without specific prior written permission.
18  *
19  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
20  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
21  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
22  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
23  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
24  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
25  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
26  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
27  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
28  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
29  * SUCH DAMAGE.
30  */
31 
32 #ifndef lint
33 static const char copyright[] =
34 "@(#) Copyright (c) 1980, 1989, 1993\n\
35 	The Regents of the University of California.  All rights reserved.\n";
36 #endif /* not lint */
37 
38 #ifndef lint
39 #if 0
40 static char sccsid[] = "@(#)umount.c	8.8 (Berkeley) 5/8/95";
41 #endif
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 	if ((argc == 0 && !all) || (argc != 0 && all))
138 		usage();
139 
140 	if (nfsforce != 0 && (argc == 0 || nfshost != NULL || typelist != NULL))
141 		usage();
142 
143 	/* -h implies "-t nfs" if no -t flag. */
144 	if ((nfshost != NULL) && (typelist == NULL))
145 		typelist = makevfslist("nfs");
146 
147 	if (nfshost != NULL) {
148 		memset(&hints, 0, sizeof hints);
149 		error = getaddrinfo(nfshost, NULL, &hints, &nfshost_ai);
150 		if (error)
151 			errx(1, "%s: %s", nfshost, gai_strerror(error));
152 	}
153 
154 	switch (all) {
155 	case 2:
156 		if ((mntsize = mntinfo(&mntbuf)) <= 0)
157 			break;
158 		/*
159 		 * We unmount the nfs-mounts in the reverse order
160 		 * that they were mounted.
161 		 */
162 		for (errs = 0, mntsize--; mntsize > 0; mntsize--) {
163 			sfs = &mntbuf[mntsize];
164 			if (checkvfsname(sfs->f_fstypename, typelist))
165 				continue;
166 			if (strcmp(sfs->f_mntonname, "/dev") == 0)
167 				continue;
168 			if (umountfs(sfs) != 0)
169 				errs = 1;
170 		}
171 		free(mntbuf);
172 		break;
173 	case 1:
174 		if (setfsent() == 0)
175 			err(1, "%s", getfstab());
176 		errs = umountall(typelist);
177 		break;
178 	case 0:
179 		for (errs = 0; *argv != NULL; ++argv)
180 			if (nfsforce != 0) {
181 				/*
182 				 * First do the nfssvc() syscall to shut down
183 				 * the mount point and then do the forced
184 				 * dismount.
185 				 */
186 				ret = nfssvc(NFSSVC_FORCEDISM, *argv);
187 				if (ret >= 0)
188 					ret = unmount(*argv, MNT_FORCE);
189 				if (ret < 0) {
190 					warn("%s", *argv);
191 					errs = 1;
192 				}
193 			} else if (checkname(*argv, typelist) != 0)
194 				errs = 1;
195 		break;
196 	}
197 	exit(errs);
198 }
199 
200 int
201 umountall(char **typelist)
202 {
203 	struct xvfsconf vfc;
204 	struct fstab *fs;
205 	int rval;
206 	char *cp;
207 	static int firstcall = 1;
208 
209 	if ((fs = getfsent()) != NULL)
210 		firstcall = 0;
211 	else if (firstcall)
212 		errx(1, "fstab reading failure");
213 	else
214 		return (0);
215 	do {
216 		/* Ignore the root. */
217 		if (strcmp(fs->fs_file, "/") == 0)
218 			continue;
219 		/*
220 		 * !!!
221 		 * Historic practice: ignore unknown FSTAB_* fields.
222 		 */
223 		if (strcmp(fs->fs_type, FSTAB_RW) &&
224 		    strcmp(fs->fs_type, FSTAB_RO) &&
225 		    strcmp(fs->fs_type, FSTAB_RQ))
226 			continue;
227 		/* Ignore unknown file system types. */
228 		if (getvfsbyname(fs->fs_vfstype, &vfc) == -1)
229 			continue;
230 		if (checkvfsname(fs->fs_vfstype, typelist))
231 			continue;
232 
233 		/*
234 		 * We want to unmount the file systems in the reverse order
235 		 * that they were mounted.  So, we save off the file name
236 		 * in some allocated memory, and then call recursively.
237 		 */
238 		if ((cp = malloc((size_t)strlen(fs->fs_file) + 1)) == NULL)
239 			err(1, "malloc failed");
240 		(void)strcpy(cp, fs->fs_file);
241 		rval = umountall(typelist);
242 		rval = checkname(cp, typelist) || rval;
243 		free(cp);
244 		return (rval);
245 	} while ((fs = getfsent()) != NULL);
246 	return (0);
247 }
248 
249 /*
250  * Do magic checks on mountpoint/device/fsid, and then call unmount(2).
251  */
252 int
253 checkname(char *mntname, char **typelist)
254 {
255 	char buf[MAXPATHLEN];
256 	struct statfs sfsbuf;
257 	struct stat sb;
258 	struct statfs *sfs;
259 	char *delimp;
260 	dev_t dev;
261 	int len;
262 
263 	/*
264 	 * 1. Check if the name exists in the mounttable.
265 	 */
266 	sfs = checkmntlist(mntname);
267 	/*
268 	 * 2. Remove trailing slashes if there are any. After that
269 	 * we look up the name in the mounttable again.
270 	 */
271 	if (sfs == NULL) {
272 		len = strlen(mntname);
273 		while (len > 1 && mntname[len - 1] == '/')
274 			mntname[--len] = '\0';
275 		sfs = checkmntlist(mntname);
276 	}
277 	/*
278 	 * 3. Check if the deprecated NFS syntax with an '@' has been used
279 	 * and translate it to the ':' syntax. Look up the name in the
280 	 * mount table again.
281 	 */
282 	if (sfs == NULL && (delimp = strrchr(mntname, '@')) != NULL) {
283 		snprintf(buf, sizeof(buf), "%s:%.*s", delimp + 1,
284 		    (int)(delimp - mntname), mntname);
285 		len = strlen(buf);
286 		while (len > 1 && buf[len - 1] == '/')
287 			buf[--len] = '\0';
288 		sfs = checkmntlist(buf);
289 	}
290 	/*
291 	 * 4. Resort to a statfs(2) call. This is the last check so that
292 	 * hung NFS filesystems for example can be unmounted without
293 	 * potentially blocking forever in statfs() as long as the
294 	 * filesystem is specified unambiguously. This covers all the
295 	 * hard cases such as symlinks and mismatches between the
296 	 * mount list and reality.
297 	 * We also do this if an ambiguous mount point was specified.
298 	 */
299 	if (sfs == NULL || (getmntentry(NULL, mntname, NULL, FIND) != NULL &&
300 	    getmntentry(NULL, mntname, NULL, CHECKUNIQUE) == NULL)) {
301 		if (statfs(mntname, &sfsbuf) != 0) {
302 			warn("%s: statfs", mntname);
303 		} else if (stat(mntname, &sb) != 0) {
304 			warn("%s: stat", mntname);
305 		} else if (S_ISDIR(sb.st_mode)) {
306 			/* Check that `mntname' is the root directory. */
307 			dev = sb.st_dev;
308 			snprintf(buf, sizeof(buf), "%s/..", mntname);
309 			if (stat(buf, &sb) != 0) {
310 				warn("%s: stat", buf);
311 			} else if (sb.st_dev == dev) {
312 				warnx("%s: not a file system root directory",
313 				    mntname);
314 				return (1);
315 			} else
316 				sfs = &sfsbuf;
317 		}
318 	}
319 	if (sfs == NULL) {
320 		warnx("%s: unknown file system", mntname);
321 		return (1);
322 	}
323 	if (checkvfsname(sfs->f_fstypename, typelist))
324 		return (1);
325 	return (umountfs(sfs));
326 }
327 
328 /*
329  * NFS stuff and unmount(2) call
330  */
331 int
332 umountfs(struct statfs *sfs)
333 {
334 	char fsidbuf[64];
335 	enum clnt_stat clnt_stat;
336 	struct timeval try;
337 	struct addrinfo *ai, hints;
338 	int do_rpc;
339 	CLIENT *clp;
340 	char *nfsdirname, *orignfsdirname;
341 	char *hostp, *delimp;
342 	char buf[1024];
343 	struct nfscl_dumpmntopts dumpmntopts;
344 	const char *proto_ptr = NULL;
345 
346 	ai = NULL;
347 	do_rpc = 0;
348 	hostp = NULL;
349 	nfsdirname = delimp = orignfsdirname = NULL;
350 	memset(&hints, 0, sizeof hints);
351 
352 	if (strcmp(sfs->f_fstypename, "nfs") == 0) {
353 		if ((nfsdirname = strdup(sfs->f_mntfromname)) == NULL)
354 			err(1, "strdup");
355 		orignfsdirname = nfsdirname;
356 		if (*nfsdirname == '[' &&
357 		    (delimp = strchr(nfsdirname + 1, ']')) != NULL &&
358 		    *(delimp + 1) == ':') {
359 			hostp = nfsdirname + 1;
360 			nfsdirname = delimp + 2;
361 		} else if ((delimp = strrchr(nfsdirname, ':')) != NULL) {
362 			hostp = nfsdirname;
363 			nfsdirname = delimp + 1;
364 		}
365 		if (hostp != NULL) {
366 			*delimp = '\0';
367 			getaddrinfo(hostp, NULL, &hints, &ai);
368 			if (ai == NULL) {
369 				warnx("can't get net id for host");
370 			}
371 		}
372 
373 		/*
374 		 * Check if we have to start the rpc-call later.
375 		 * If there are still identical nfs-names mounted,
376 		 * we skip the rpc-call. Obviously this has to
377 		 * happen before unmount(2), but it should happen
378 		 * after the previous namecheck.
379 		 * A non-NULL return means that this is the last
380 		 * mount from mntfromname that is still mounted.
381 		 */
382 		if (getmntentry(sfs->f_mntfromname, NULL, NULL,
383 		    CHECKUNIQUE) != NULL) {
384 			do_rpc = 1;
385 			proto_ptr = "udp";
386 			/*
387 			 * Try and find out whether this NFS mount is NFSv4 and
388 			 * what protocol is being used. If this fails, the
389 			 * default is NFSv2,3 and use UDP for the Unmount RPC.
390 			 */
391 			dumpmntopts.ndmnt_fname = sfs->f_mntonname;
392 			dumpmntopts.ndmnt_buf = buf;
393 			dumpmntopts.ndmnt_blen = sizeof(buf);
394 			if (nfssvc(NFSSVC_DUMPMNTOPTS, &dumpmntopts) >= 0) {
395 				if (strstr(buf, "nfsv4,") != NULL)
396 					do_rpc = 0;
397 				else if (strstr(buf, ",tcp,") != NULL)
398 					proto_ptr = "tcp";
399 			}
400 		}
401 	}
402 
403 	if (!namematch(ai)) {
404 		free(orignfsdirname);
405 		return (1);
406 	}
407 	/* First try to unmount using the file system ID. */
408 	snprintf(fsidbuf, sizeof(fsidbuf), "FSID:%d:%d", sfs->f_fsid.val[0],
409 	    sfs->f_fsid.val[1]);
410 	if (unmount(fsidbuf, fflag | MNT_BYFSID) != 0) {
411 		/* XXX, non-root users get a zero fsid, so don't warn. */
412 		if (errno != ENOENT || sfs->f_fsid.val[0] != 0 ||
413 		    sfs->f_fsid.val[1] != 0)
414 			warn("unmount of %s failed", sfs->f_mntonname);
415 		if (errno != ENOENT) {
416 			free(orignfsdirname);
417 			return (1);
418 		}
419 		/* Compatibility for old kernels. */
420 		if (sfs->f_fsid.val[0] != 0 || sfs->f_fsid.val[1] != 0)
421 			warnx("retrying using path instead of file system ID");
422 		if (unmount(sfs->f_mntonname, fflag) != 0) {
423 			warn("unmount of %s failed", sfs->f_mntonname);
424 			free(orignfsdirname);
425 			return (1);
426 		}
427 	}
428 	/* Mark this file system as unmounted. */
429 	getmntentry(NULL, NULL, &sfs->f_fsid, REMOVE);
430 	if (vflag)
431 		(void)printf("%s: unmount from %s\n", sfs->f_mntfromname,
432 		    sfs->f_mntonname);
433 	/*
434 	 * Report to mountd-server which nfsname
435 	 * has been unmounted.
436 	 */
437 	if (ai != NULL && !(fflag & MNT_FORCE) && do_rpc) {
438 		clp = clnt_create(hostp, MOUNTPROG, MOUNTVERS3, proto_ptr);
439 		if (clp  == NULL) {
440 			warnx("%s: %s", hostp,
441 			    clnt_spcreateerror("MOUNTPROG"));
442 			free(orignfsdirname);
443 			return (1);
444 		}
445 		clp->cl_auth = authsys_create_default();
446 		try.tv_sec = 20;
447 		try.tv_usec = 0;
448 		clnt_stat = clnt_call(clp, MOUNTPROC_UMNT, (xdrproc_t)xdr_dir,
449 		    nfsdirname, (xdrproc_t)xdr_void, (caddr_t)0, try);
450 		if (clnt_stat != RPC_SUCCESS) {
451 			warnx("%s: %s", hostp,
452 			    clnt_sperror(clp, "RPCMNT_UMOUNT"));
453 			free(orignfsdirname);
454 			return (1);
455 		}
456 		/*
457 		 * Remove the unmounted entry from /var/db/mounttab.
458 		 */
459 		if (read_mtab()) {
460 			clean_mtab(hostp, nfsdirname, vflag);
461 			if(!write_mtab(vflag))
462 				warnx("cannot remove mounttab entry %s:%s",
463 				    hostp, nfsdirname);
464 			free_mtab();
465 		}
466 		auth_destroy(clp->cl_auth);
467 		clnt_destroy(clp);
468 	}
469 	free(orignfsdirname);
470 	return (0);
471 }
472 
473 struct statfs *
474 getmntentry(const char *fromname, const char *onname, fsid_t *fsid, dowhat what)
475 {
476 	static struct statfs *mntbuf;
477 	static size_t mntsize = 0;
478 	static int *mntcheck = NULL;
479 	struct statfs *sfs, *foundsfs;
480 	int i, count;
481 
482 	if (mntsize <= 0) {
483 		if ((mntsize = mntinfo(&mntbuf)) <= 0)
484 			return (NULL);
485 	}
486 	if (mntcheck == NULL) {
487 		if ((mntcheck = calloc(mntsize + 1, sizeof(int))) == NULL)
488 			err(1, "calloc");
489 	}
490 	/*
491 	 * We want to get the file systems in the reverse order
492 	 * that they were mounted. Unmounted file systems are marked
493 	 * in a table called 'mntcheck'.
494 	 */
495 	count = 0;
496 	foundsfs = NULL;
497 	for (i = mntsize - 1; i >= 0; i--) {
498 		if (mntcheck[i])
499 			continue;
500 		sfs = &mntbuf[i];
501 		if (fromname != NULL && strcmp(sfs->f_mntfromname,
502 		    fromname) != 0)
503 			continue;
504 		if (onname != NULL && strcmp(sfs->f_mntonname, onname) != 0)
505 			continue;
506 		if (fsid != NULL && fsidcmp(&sfs->f_fsid, fsid) != 0)
507 			continue;
508 
509 		switch (what) {
510 		case CHECKUNIQUE:
511 			foundsfs = sfs;
512 			count++;
513 			continue;
514 		case REMOVE:
515 			mntcheck[i] = 1;
516 			break;
517 		default:
518 			break;
519 		}
520 		return (sfs);
521 	}
522 
523 	if (what == CHECKUNIQUE && count == 1)
524 		return (foundsfs);
525 	return (NULL);
526 }
527 
528 int
529 sacmp(void *sa1, void *sa2)
530 {
531 	void *p1, *p2;
532 	int len;
533 
534 	if (((struct sockaddr *)sa1)->sa_family !=
535 	    ((struct sockaddr *)sa2)->sa_family)
536 		return (1);
537 
538 	switch (((struct sockaddr *)sa1)->sa_family) {
539 	case AF_INET:
540 		p1 = &((struct sockaddr_in *)sa1)->sin_addr;
541 		p2 = &((struct sockaddr_in *)sa2)->sin_addr;
542 		len = 4;
543 		break;
544 	case AF_INET6:
545 		p1 = &((struct sockaddr_in6 *)sa1)->sin6_addr;
546 		p2 = &((struct sockaddr_in6 *)sa2)->sin6_addr;
547 		len = 16;
548 		if (((struct sockaddr_in6 *)sa1)->sin6_scope_id !=
549 		    ((struct sockaddr_in6 *)sa2)->sin6_scope_id)
550 			return (1);
551 		break;
552 	default:
553 		return (1);
554 	}
555 
556 	return memcmp(p1, p2, len);
557 }
558 
559 int
560 namematch(struct addrinfo *ai)
561 {
562 	struct addrinfo *aip;
563 
564 	if (nfshost == NULL || nfshost_ai == NULL)
565 		return (1);
566 
567 	while (ai != NULL) {
568 		aip = nfshost_ai;
569 		while (aip != NULL) {
570 			if (sacmp(ai->ai_addr, aip->ai_addr) == 0)
571 				return (1);
572 			aip = aip->ai_next;
573 		}
574 		ai = ai->ai_next;
575 	}
576 
577 	return (0);
578 }
579 
580 struct statfs *
581 checkmntlist(char *mntname)
582 {
583 	struct statfs *sfs;
584 	fsid_t fsid;
585 
586 	sfs = NULL;
587 	if (parsehexfsid(mntname, &fsid) == 0)
588 		sfs = getmntentry(NULL, NULL, &fsid, FIND);
589 	if (sfs == NULL)
590 		sfs = getmntentry(NULL, mntname, NULL, FIND);
591 	if (sfs == NULL)
592 		sfs = getmntentry(mntname, NULL, NULL, FIND);
593 	return (sfs);
594 }
595 
596 size_t
597 mntinfo(struct statfs **mntbuf)
598 {
599 	static struct statfs *origbuf;
600 	size_t bufsize;
601 	int mntsize;
602 
603 	mntsize = getfsstat(NULL, 0, MNT_NOWAIT);
604 	if (mntsize <= 0)
605 		return (0);
606 	bufsize = (mntsize + 1) * sizeof(struct statfs);
607 	if ((origbuf = malloc(bufsize)) == NULL)
608 		err(1, "malloc");
609 	mntsize = getfsstat(origbuf, (long)bufsize, MNT_NOWAIT);
610 	*mntbuf = origbuf;
611 	return (mntsize);
612 }
613 
614 /*
615  * Convert a hexadecimal filesystem ID to an fsid_t.
616  * Returns 0 on success.
617  */
618 int
619 parsehexfsid(const char *hex, fsid_t *fsid)
620 {
621 	char hexbuf[3];
622 	int i;
623 
624 	if (strlen(hex) != sizeof(*fsid) * 2)
625 		return (-1);
626 	hexbuf[2] = '\0';
627 	for (i = 0; i < (int)sizeof(*fsid); i++) {
628 		hexbuf[0] = hex[i * 2];
629 		hexbuf[1] = hex[i * 2 + 1];
630 		if (!isxdigit(hexbuf[0]) || !isxdigit(hexbuf[1]))
631 			return (-1);
632 		((u_char *)fsid)[i] = strtol(hexbuf, NULL, 16);
633 	}
634 	return (0);
635 }
636 
637 /*
638  * xdr routines for mount rpc's
639  */
640 int
641 xdr_dir(XDR *xdrsp, char *dirp)
642 {
643 
644 	return (xdr_string(xdrsp, &dirp, MNTPATHLEN));
645 }
646 
647 void
648 usage(void)
649 {
650 
651 	(void)fprintf(stderr, "%s\n%s\n",
652 	    "usage: umount [-fNnv] special ... | node ... | fsid ...",
653 	    "       umount -a | -A [-F fstab] [-fnv] [-h host] [-t type]");
654 	exit(1);
655 }
656