xref: /freebsd/sbin/umount/umount.c (revision f5463265955b829775bbb32e1fd0bc11dafc36ce)
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 #include <sys/param.h>
33 #include <sys/mount.h>
34 #include <sys/socket.h>
35 #include <sys/stat.h>
36 
37 #include <netdb.h>
38 #include <rpc/rpc.h>
39 #include <rpcsvc/mount.h>
40 #include <nfs/nfssvc.h>
41 
42 #include <ctype.h>
43 #include <err.h>
44 #include <errno.h>
45 #include <fstab.h>
46 #include <stdio.h>
47 #include <stdlib.h>
48 #include <string.h>
49 #include <unistd.h>
50 
51 #include "mounttab.h"
52 
53 typedef enum { FIND, REMOVE, CHECKUNIQUE } dowhat;
54 
55 static struct addrinfo *nfshost_ai = NULL;
56 static int	fflag, vflag;
57 static char	*nfshost;
58 
59 struct statfs *checkmntlist(char *);
60 int	 checkvfsname (const char *, char **);
61 struct statfs *getmntentry(const char *fromname, const char *onname,
62 	     fsid_t *fsid, dowhat what);
63 char   **makevfslist (const char *);
64 size_t	 mntinfo (struct statfs **);
65 int	 namematch (struct addrinfo *);
66 int	 parsehexfsid(const char *hex, fsid_t *fsid);
67 int	 sacmp (void *, void *);
68 int	 umountall (char **);
69 int	 checkname (char *, char **);
70 int	 umountfs(struct statfs *sfs);
71 void	 usage (void);
72 int	 xdr_dir (XDR *, char *);
73 
74 int
75 main(int argc, char *argv[])
76 {
77 	int all, errs, ch, mntsize, error, nfsforce, ret;
78 	char **typelist = NULL;
79 	struct statfs *mntbuf, *sfs;
80 	struct addrinfo hints;
81 
82 	nfsforce = all = errs = 0;
83 	while ((ch = getopt(argc, argv, "AaF:fh:Nnt:v")) != -1)
84 		switch (ch) {
85 		case 'A':
86 			all = 2;
87 			break;
88 		case 'a':
89 			all = 1;
90 			break;
91 		case 'F':
92 			setfstab(optarg);
93 			break;
94 		case 'f':
95 			fflag |= MNT_FORCE;
96 			break;
97 		case 'h':	/* -h implies -A. */
98 			all = 2;
99 			nfshost = optarg;
100 			break;
101 		case 'N':
102 			nfsforce = 1;
103 			break;
104 		case 'n':
105 			fflag |= MNT_NONBUSY;
106 			break;
107 		case 't':
108 			if (typelist != NULL)
109 				err(1, "only one -t option may be specified");
110 			typelist = makevfslist(optarg);
111 			break;
112 		case 'v':
113 			vflag = 1;
114 			break;
115 		default:
116 			usage();
117 			/* NOTREACHED */
118 		}
119 	argc -= optind;
120 	argv += optind;
121 
122 	if ((fflag & MNT_FORCE) != 0 && (fflag & MNT_NONBUSY) != 0)
123 		err(1, "-f and -n are mutually exclusive");
124 
125 	if ((argc == 0 && !all) || (argc != 0 && all))
126 		usage();
127 
128 	if (nfsforce != 0 && (argc == 0 || nfshost != NULL || typelist != NULL))
129 		usage();
130 
131 	/* -h implies "-t nfs" if no -t flag. */
132 	if ((nfshost != NULL) && (typelist == NULL))
133 		typelist = makevfslist("nfs");
134 
135 	if (nfshost != NULL) {
136 		memset(&hints, 0, sizeof hints);
137 		error = getaddrinfo(nfshost, NULL, &hints, &nfshost_ai);
138 		if (error)
139 			errx(1, "%s: %s", nfshost, gai_strerror(error));
140 	}
141 
142 	switch (all) {
143 	case 2:
144 		if ((mntsize = mntinfo(&mntbuf)) <= 0)
145 			break;
146 		/*
147 		 * We unmount the nfs-mounts in the reverse order
148 		 * that they were mounted.
149 		 */
150 		for (errs = 0, mntsize--; mntsize > 0; mntsize--) {
151 			sfs = &mntbuf[mntsize];
152 			if (checkvfsname(sfs->f_fstypename, typelist))
153 				continue;
154 			if (strcmp(sfs->f_mntonname, "/dev") == 0)
155 				continue;
156 			if (umountfs(sfs) != 0)
157 				errs = 1;
158 		}
159 		free(mntbuf);
160 		break;
161 	case 1:
162 		if (setfsent() == 0)
163 			err(1, "%s", getfstab());
164 		errs = umountall(typelist);
165 		break;
166 	case 0:
167 		for (errs = 0; *argv != NULL; ++argv)
168 			if (nfsforce != 0) {
169 				/*
170 				 * First do the nfssvc() syscall to shut down
171 				 * the mount point and then do the forced
172 				 * dismount.
173 				 */
174 				ret = nfssvc(NFSSVC_FORCEDISM, *argv);
175 				if (ret >= 0)
176 					ret = unmount(*argv, MNT_FORCE);
177 				if (ret < 0) {
178 					warn("%s", *argv);
179 					errs = 1;
180 				}
181 			} else if (checkname(*argv, typelist) != 0)
182 				errs = 1;
183 		break;
184 	}
185 	exit(errs);
186 }
187 
188 int
189 umountall(char **typelist)
190 {
191 	struct xvfsconf vfc;
192 	struct fstab *fs;
193 	int rval;
194 	char *cp;
195 	static int firstcall = 1;
196 
197 	if ((fs = getfsent()) != NULL)
198 		firstcall = 0;
199 	else if (firstcall)
200 		errx(1, "fstab reading failure");
201 	else
202 		return (0);
203 	do {
204 		/* Ignore the root. */
205 		if (strcmp(fs->fs_file, "/") == 0)
206 			continue;
207 		/*
208 		 * !!!
209 		 * Historic practice: ignore unknown FSTAB_* fields.
210 		 */
211 		if (strcmp(fs->fs_type, FSTAB_RW) &&
212 		    strcmp(fs->fs_type, FSTAB_RO) &&
213 		    strcmp(fs->fs_type, FSTAB_RQ))
214 			continue;
215 		/* Ignore unknown file system types. */
216 		if (getvfsbyname(fs->fs_vfstype, &vfc) == -1)
217 			continue;
218 		if (checkvfsname(fs->fs_vfstype, typelist))
219 			continue;
220 
221 		/*
222 		 * We want to unmount the file systems in the reverse order
223 		 * that they were mounted.  So, we save off the file name
224 		 * in some allocated memory, and then call recursively.
225 		 */
226 		if ((cp = malloc((size_t)strlen(fs->fs_file) + 1)) == NULL)
227 			err(1, "malloc failed");
228 		(void)strcpy(cp, fs->fs_file);
229 		rval = umountall(typelist);
230 		rval = checkname(cp, typelist) || rval;
231 		free(cp);
232 		return (rval);
233 	} while ((fs = getfsent()) != NULL);
234 	return (0);
235 }
236 
237 /*
238  * Do magic checks on mountpoint/device/fsid, and then call unmount(2).
239  */
240 int
241 checkname(char *mntname, char **typelist)
242 {
243 	char buf[MAXPATHLEN];
244 	struct statfs sfsbuf;
245 	struct stat sb;
246 	struct statfs *sfs;
247 	char *delimp;
248 	dev_t dev;
249 	int len;
250 
251 	/*
252 	 * 1. Check if the name exists in the mounttable.
253 	 */
254 	sfs = checkmntlist(mntname);
255 	/*
256 	 * 2. Remove trailing slashes if there are any. After that
257 	 * we look up the name in the mounttable again.
258 	 */
259 	if (sfs == NULL) {
260 		len = strlen(mntname);
261 		while (len > 1 && mntname[len - 1] == '/')
262 			mntname[--len] = '\0';
263 		sfs = checkmntlist(mntname);
264 	}
265 	/*
266 	 * 3. Check if the deprecated NFS syntax with an '@' has been used
267 	 * and translate it to the ':' syntax. Look up the name in the
268 	 * mount table again.
269 	 */
270 	if (sfs == NULL && (delimp = strrchr(mntname, '@')) != NULL) {
271 		snprintf(buf, sizeof(buf), "%s:%.*s", delimp + 1,
272 		    (int)(delimp - mntname), mntname);
273 		len = strlen(buf);
274 		while (len > 1 && buf[len - 1] == '/')
275 			buf[--len] = '\0';
276 		sfs = checkmntlist(buf);
277 	}
278 	/*
279 	 * 4. Resort to a statfs(2) call. This is the last check so that
280 	 * hung NFS filesystems for example can be unmounted without
281 	 * potentially blocking forever in statfs() as long as the
282 	 * filesystem is specified unambiguously. This covers all the
283 	 * hard cases such as symlinks and mismatches between the
284 	 * mount list and reality.
285 	 * We also do this if an ambiguous mount point was specified.
286 	 */
287 	if (sfs == NULL || (getmntentry(NULL, mntname, NULL, FIND) != NULL &&
288 	    getmntentry(NULL, mntname, NULL, CHECKUNIQUE) == NULL)) {
289 		if (statfs(mntname, &sfsbuf) != 0) {
290 			warn("%s: statfs", mntname);
291 		} else if (stat(mntname, &sb) != 0) {
292 			warn("%s: stat", mntname);
293 		} else if (S_ISDIR(sb.st_mode)) {
294 			/* Check that `mntname' is the root directory. */
295 			dev = sb.st_dev;
296 			snprintf(buf, sizeof(buf), "%s/..", mntname);
297 			if (stat(buf, &sb) != 0) {
298 				warn("%s: stat", buf);
299 			} else if (sb.st_dev == dev) {
300 				warnx("%s: not a file system root directory",
301 				    mntname);
302 				return (1);
303 			} else
304 				sfs = &sfsbuf;
305 		}
306 	}
307 	if (sfs == NULL) {
308 		warnx("%s: unknown file system", mntname);
309 		return (1);
310 	}
311 	if (checkvfsname(sfs->f_fstypename, typelist))
312 		return (1);
313 	return (umountfs(sfs));
314 }
315 
316 /*
317  * NFS stuff and unmount(2) call
318  */
319 int
320 umountfs(struct statfs *sfs)
321 {
322 	char fsidbuf[64];
323 	enum clnt_stat clnt_stat;
324 	struct timeval try;
325 	struct addrinfo *ai, hints;
326 	int do_rpc;
327 	CLIENT *clp;
328 	char *nfsdirname, *orignfsdirname;
329 	char *hostp, *delimp;
330 	char buf[1024];
331 	struct nfscl_dumpmntopts dumpmntopts;
332 	const char *proto_ptr = NULL;
333 
334 	ai = NULL;
335 	do_rpc = 0;
336 	hostp = NULL;
337 	nfsdirname = delimp = orignfsdirname = NULL;
338 	memset(&hints, 0, sizeof hints);
339 
340 	if (strcmp(sfs->f_fstypename, "nfs") == 0) {
341 		if ((nfsdirname = strdup(sfs->f_mntfromname)) == NULL)
342 			err(1, "strdup");
343 		orignfsdirname = nfsdirname;
344 		if (*nfsdirname == '[' &&
345 		    (delimp = strchr(nfsdirname + 1, ']')) != NULL &&
346 		    *(delimp + 1) == ':') {
347 			hostp = nfsdirname + 1;
348 			nfsdirname = delimp + 2;
349 		} else if ((delimp = strrchr(nfsdirname, ':')) != NULL) {
350 			hostp = nfsdirname;
351 			nfsdirname = delimp + 1;
352 		}
353 		if (hostp != NULL) {
354 			*delimp = '\0';
355 			getaddrinfo(hostp, NULL, &hints, &ai);
356 			if (ai == NULL) {
357 				warnx("can't get net id for host");
358 			}
359 		}
360 
361 		/*
362 		 * Check if we have to start the rpc-call later.
363 		 * If there are still identical nfs-names mounted,
364 		 * we skip the rpc-call. Obviously this has to
365 		 * happen before unmount(2), but it should happen
366 		 * after the previous namecheck.
367 		 * A non-NULL return means that this is the last
368 		 * mount from mntfromname that is still mounted.
369 		 */
370 		if (getmntentry(sfs->f_mntfromname, NULL, NULL,
371 		    CHECKUNIQUE) != NULL) {
372 			do_rpc = 1;
373 			proto_ptr = "udp";
374 			/*
375 			 * Try and find out whether this NFS mount is NFSv4 and
376 			 * what protocol is being used. If this fails, the
377 			 * default is NFSv2,3 and use UDP for the Unmount RPC.
378 			 */
379 			dumpmntopts.ndmnt_fname = sfs->f_mntonname;
380 			dumpmntopts.ndmnt_buf = buf;
381 			dumpmntopts.ndmnt_blen = sizeof(buf);
382 			if (nfssvc(NFSSVC_DUMPMNTOPTS, &dumpmntopts) >= 0) {
383 				if (strstr(buf, "nfsv4,") != NULL)
384 					do_rpc = 0;
385 				else if (strstr(buf, ",tcp,") != NULL)
386 					proto_ptr = "tcp";
387 			}
388 		}
389 	}
390 
391 	if (!namematch(ai)) {
392 		free(orignfsdirname);
393 		return (1);
394 	}
395 	/* First try to unmount using the file system ID. */
396 	snprintf(fsidbuf, sizeof(fsidbuf), "FSID:%d:%d", sfs->f_fsid.val[0],
397 	    sfs->f_fsid.val[1]);
398 	if (unmount(fsidbuf, fflag | MNT_BYFSID) != 0) {
399 		/* XXX, non-root users get a zero fsid, so don't warn. */
400 		if (errno != ENOENT || sfs->f_fsid.val[0] != 0 ||
401 		    sfs->f_fsid.val[1] != 0)
402 			warn("unmount of %s failed", sfs->f_mntonname);
403 		if (errno != ENOENT) {
404 			free(orignfsdirname);
405 			return (1);
406 		}
407 		/* Compatibility for old kernels. */
408 		if (sfs->f_fsid.val[0] != 0 || sfs->f_fsid.val[1] != 0)
409 			warnx("retrying using path instead of file system ID");
410 		if (unmount(sfs->f_mntonname, fflag) != 0) {
411 			warn("unmount of %s failed", sfs->f_mntonname);
412 			free(orignfsdirname);
413 			return (1);
414 		}
415 	}
416 	/* Mark this file system as unmounted. */
417 	getmntentry(NULL, NULL, &sfs->f_fsid, REMOVE);
418 	if (vflag)
419 		(void)printf("%s: unmount from %s\n", sfs->f_mntfromname,
420 		    sfs->f_mntonname);
421 	/*
422 	 * Report to mountd-server which nfsname
423 	 * has been unmounted.
424 	 */
425 	if (ai != NULL && !(fflag & MNT_FORCE) && do_rpc) {
426 		clp = clnt_create(hostp, MOUNTPROG, MOUNTVERS3, proto_ptr);
427 		if (clp  == NULL) {
428 			warnx("%s: %s", hostp,
429 			    clnt_spcreateerror("MOUNTPROG"));
430 			free(orignfsdirname);
431 			return (1);
432 		}
433 		clp->cl_auth = authsys_create_default();
434 		try.tv_sec = 20;
435 		try.tv_usec = 0;
436 		clnt_stat = clnt_call(clp, MOUNTPROC_UMNT, (xdrproc_t)xdr_dir,
437 		    nfsdirname, (xdrproc_t)xdr_void, (caddr_t)0, try);
438 		if (clnt_stat != RPC_SUCCESS) {
439 			warnx("%s: %s", hostp,
440 			    clnt_sperror(clp, "RPCMNT_UMOUNT"));
441 			free(orignfsdirname);
442 			return (1);
443 		}
444 		/*
445 		 * Remove the unmounted entry from /var/db/mounttab.
446 		 */
447 		if (read_mtab()) {
448 			clean_mtab(hostp, nfsdirname, vflag);
449 			if(!write_mtab(vflag))
450 				warnx("cannot remove mounttab entry %s:%s",
451 				    hostp, nfsdirname);
452 			free_mtab();
453 		}
454 		auth_destroy(clp->cl_auth);
455 		clnt_destroy(clp);
456 	}
457 	free(orignfsdirname);
458 	return (0);
459 }
460 
461 struct statfs *
462 getmntentry(const char *fromname, const char *onname, fsid_t *fsid, dowhat what)
463 {
464 	static struct statfs *mntbuf;
465 	static size_t mntsize = 0;
466 	static int *mntcheck = NULL;
467 	struct statfs *sfs, *foundsfs;
468 	int i, count;
469 
470 	if (mntsize <= 0) {
471 		if ((mntsize = mntinfo(&mntbuf)) <= 0)
472 			return (NULL);
473 	}
474 	if (mntcheck == NULL) {
475 		if ((mntcheck = calloc(mntsize + 1, sizeof(int))) == NULL)
476 			err(1, "calloc");
477 	}
478 	/*
479 	 * We want to get the file systems in the reverse order
480 	 * that they were mounted. Unmounted file systems are marked
481 	 * in a table called 'mntcheck'.
482 	 */
483 	count = 0;
484 	foundsfs = NULL;
485 	for (i = mntsize - 1; i >= 0; i--) {
486 		if (mntcheck[i])
487 			continue;
488 		sfs = &mntbuf[i];
489 		if (fromname != NULL && strcmp(sfs->f_mntfromname,
490 		    fromname) != 0)
491 			continue;
492 		if (onname != NULL && strcmp(sfs->f_mntonname, onname) != 0)
493 			continue;
494 		if (fsid != NULL && fsidcmp(&sfs->f_fsid, fsid) != 0)
495 			continue;
496 
497 		switch (what) {
498 		case CHECKUNIQUE:
499 			foundsfs = sfs;
500 			count++;
501 			continue;
502 		case REMOVE:
503 			mntcheck[i] = 1;
504 			break;
505 		default:
506 			break;
507 		}
508 		return (sfs);
509 	}
510 
511 	if (what == CHECKUNIQUE && count == 1)
512 		return (foundsfs);
513 	return (NULL);
514 }
515 
516 int
517 sacmp(void *sa1, void *sa2)
518 {
519 	void *p1, *p2;
520 	int len;
521 
522 	if (((struct sockaddr *)sa1)->sa_family !=
523 	    ((struct sockaddr *)sa2)->sa_family)
524 		return (1);
525 
526 	switch (((struct sockaddr *)sa1)->sa_family) {
527 	case AF_INET:
528 		p1 = &((struct sockaddr_in *)sa1)->sin_addr;
529 		p2 = &((struct sockaddr_in *)sa2)->sin_addr;
530 		len = 4;
531 		break;
532 	case AF_INET6:
533 		p1 = &((struct sockaddr_in6 *)sa1)->sin6_addr;
534 		p2 = &((struct sockaddr_in6 *)sa2)->sin6_addr;
535 		len = 16;
536 		if (((struct sockaddr_in6 *)sa1)->sin6_scope_id !=
537 		    ((struct sockaddr_in6 *)sa2)->sin6_scope_id)
538 			return (1);
539 		break;
540 	default:
541 		return (1);
542 	}
543 
544 	return memcmp(p1, p2, len);
545 }
546 
547 int
548 namematch(struct addrinfo *ai)
549 {
550 	struct addrinfo *aip;
551 
552 	if (nfshost == NULL || nfshost_ai == NULL)
553 		return (1);
554 
555 	while (ai != NULL) {
556 		aip = nfshost_ai;
557 		while (aip != NULL) {
558 			if (sacmp(ai->ai_addr, aip->ai_addr) == 0)
559 				return (1);
560 			aip = aip->ai_next;
561 		}
562 		ai = ai->ai_next;
563 	}
564 
565 	return (0);
566 }
567 
568 struct statfs *
569 checkmntlist(char *mntname)
570 {
571 	struct statfs *sfs;
572 	fsid_t fsid;
573 
574 	sfs = NULL;
575 	if (parsehexfsid(mntname, &fsid) == 0)
576 		sfs = getmntentry(NULL, NULL, &fsid, FIND);
577 	if (sfs == NULL)
578 		sfs = getmntentry(NULL, mntname, NULL, FIND);
579 	if (sfs == NULL)
580 		sfs = getmntentry(mntname, NULL, NULL, FIND);
581 	return (sfs);
582 }
583 
584 size_t
585 mntinfo(struct statfs **mntbuf)
586 {
587 	static struct statfs *origbuf;
588 	size_t bufsize;
589 	int mntsize;
590 
591 	mntsize = getfsstat(NULL, 0, MNT_NOWAIT);
592 	if (mntsize <= 0)
593 		return (0);
594 	bufsize = (mntsize + 1) * sizeof(struct statfs);
595 	if ((origbuf = malloc(bufsize)) == NULL)
596 		err(1, "malloc");
597 	mntsize = getfsstat(origbuf, (long)bufsize, MNT_NOWAIT);
598 	*mntbuf = origbuf;
599 	return (mntsize);
600 }
601 
602 /*
603  * Convert a hexadecimal filesystem ID to an fsid_t.
604  * Returns 0 on success.
605  */
606 int
607 parsehexfsid(const char *hex, fsid_t *fsid)
608 {
609 	char hexbuf[3];
610 	int i;
611 
612 	if (strlen(hex) != sizeof(*fsid) * 2)
613 		return (-1);
614 	hexbuf[2] = '\0';
615 	for (i = 0; i < (int)sizeof(*fsid); i++) {
616 		hexbuf[0] = hex[i * 2];
617 		hexbuf[1] = hex[i * 2 + 1];
618 		if (!isxdigit(hexbuf[0]) || !isxdigit(hexbuf[1]))
619 			return (-1);
620 		((u_char *)fsid)[i] = strtol(hexbuf, NULL, 16);
621 	}
622 	return (0);
623 }
624 
625 /*
626  * xdr routines for mount rpc's
627  */
628 int
629 xdr_dir(XDR *xdrsp, char *dirp)
630 {
631 
632 	return (xdr_string(xdrsp, &dirp, MNTPATHLEN));
633 }
634 
635 void
636 usage(void)
637 {
638 
639 	(void)fprintf(stderr, "%s\n%s\n",
640 	    "usage: umount [-fNnv] special ... | node ... | fsid ...",
641 	    "       umount -a | -A [-F fstab] [-fnv] [-h host] [-t type]");
642 	exit(1);
643 }
644