xref: /illumos-gate/usr/src/cmd/fs.d/nfs/umount/umount.c (revision 1ce19511)
1 /*
2  * CDDL HEADER START
3  *
4  * The contents of this file are subject to the terms of the
5  * Common Development and Distribution License (the "License").
6  * You may not use this file except in compliance with the License.
7  *
8  * You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE
9  * or http://www.opensolaris.org/os/licensing.
10  * See the License for the specific language governing permissions
11  * and limitations under the License.
12  *
13  * When distributing Covered Code, include this CDDL HEADER in each
14  * file and include the License file at usr/src/OPENSOLARIS.LICENSE.
15  * If applicable, add the following below this CDDL HEADER, with the
16  * fields enclosed by brackets "[]" replaced with your own identifying
17  * information: Portions Copyright [yyyy] [name of copyright owner]
18  *
19  * CDDL HEADER END
20  */
21 
22 /*
23  * Copyright 2007 Sun Microsystems, Inc.  All rights reserved.
24  * Use is subject to license terms.
25  */
26 
27 /*	Copyright (c) 1984, 1986, 1987, 1988, 1989 AT&T	*/
28 /*	  All Rights Reserved  	*/
29 
30 /*
31  * University Copyright- Copyright (c) 1982, 1986, 1988
32  * The Regents of the University of California
33  * All Rights Reserved
34  *
35  * University Acknowledgment- Portions of this document are derived from
36  * software developed by the University of California, Berkeley, and its
37  * contributors.
38  */
39 
40 #pragma ident	"%Z%%M%	%I%	%E% SMI"
41 
42 /*
43  * nfs umount
44  */
45 
46 #include <stdio.h>
47 #include <stdlib.h>
48 #include <string.h>
49 #include <stdarg.h>
50 #include <signal.h>
51 #include <unistd.h>
52 #include <kstat.h>
53 #include <rpc/rpc.h>
54 #include <sys/mnttab.h>
55 #include <sys/mount.h>
56 #include <sys/mntent.h>
57 #include <nfs/nfs.h>
58 #include <nfs/nfs_clnt.h>
59 #include <rpcsvc/mount.h>
60 #include <errno.h>
61 #include <locale.h>
62 #include <fslib.h>
63 #include <priv.h>
64 #include <tsol/label.h>
65 #include "replica.h"
66 
67 #define	RET_OK	0
68 #define	RET_ERR	32
69 
70 #ifdef __STDC__
71 static void pr_err(const char *fmt, ...);
72 #else
73 static void pr_err(char *fmt, va_dcl);
74 #endif
75 static	void	usage();
76 static	int	nfs_unmount(char *, int);
77 static	void	inform_server(char *, char *, bool_t);
78 static	struct extmnttab *mnttab_find();
79 extern int __clnt_bindresvport(CLIENT *);
80 
81 static	int is_v4_mount(struct extmnttab *);
82 
83 static char *myname;
84 static char typename[64];
85 
86 int
main(int argc,char * argv[])87 main(int argc, char *argv[])
88 {
89 	extern int optind;
90 	int c;
91 	int umnt_flag = 0;
92 
93 	(void) setlocale(LC_ALL, "");
94 
95 #if !defined(TEXT_DOMAIN)
96 #define	TEXT_DOMAIN "SYS_TEST"
97 #endif
98 	(void) textdomain(TEXT_DOMAIN);
99 
100 	myname = strrchr(argv[0], '/');
101 	myname = myname ? myname+1 : argv[0];
102 	(void) snprintf(typename, sizeof (typename), "nfs %s", myname);
103 	argv[0] = typename;
104 
105 	/*
106 	 * Set options
107 	 */
108 	while ((c = getopt(argc, argv, "f")) != EOF) {
109 		switch (c) {
110 		case 'f':
111 			umnt_flag |= MS_FORCE; /* forced unmount is desired */
112 			break;
113 		default:
114 			usage();
115 			exit(RET_ERR);
116 		}
117 	}
118 	if (argc - optind != 1) {
119 		usage();
120 		exit(RET_ERR);
121 	}
122 
123 	if (!priv_ineffect(PRIV_SYS_MOUNT) ||
124 	    !priv_ineffect(PRIV_NET_PRIVADDR)) {
125 		pr_err(gettext("insufficient privileges\n"));
126 		exit(RET_ERR);
127 	}
128 
129 	/*
130 	 * On a labeled system, a MAC flag may be needed if the mount is
131 	 * read-down, so attempt to assert it but ignore errors in any case.
132 	 */
133 	if (is_system_labeled())
134 		(void) setpflags(NET_MAC_AWARE, 1);
135 
136 	/*
137 	 * exit, really
138 	 */
139 	return (nfs_unmount(argv[optind], umnt_flag));
140 }
141 
142 static void
pr_err(const char * fmt,...)143 pr_err(const char *fmt, ...)
144 {
145 	va_list ap;
146 
147 	va_start(ap, fmt);
148 	(void) fprintf(stderr, "%s: ", typename);
149 	(void) vfprintf(stderr, fmt, ap);
150 	(void) fflush(stderr);
151 	va_end(ap);
152 }
153 
154 static void
usage()155 usage()
156 {
157 	(void) fprintf(stderr,
158 	    gettext("Usage: nfs umount [-f] {server:path | dir}\n"));
159 	exit(RET_ERR);
160 }
161 
162 static int
nfs_unmount(char * pathname,int umnt_flag)163 nfs_unmount(char *pathname, int umnt_flag)
164 {
165 	struct extmnttab *mntp;
166 	bool_t quick = FALSE;
167 	int is_v4 = FALSE;
168 
169 	mntp = mnttab_find(pathname);
170 	if (mntp) {
171 		pathname = mntp->mnt_mountp;
172 	}
173 
174 	if (mntp)
175 		is_v4 = is_v4_mount(mntp);
176 
177 	/* Forced unmount will almost always be successful */
178 	if (umount2(pathname, umnt_flag) < 0) {
179 		if (errno == EBUSY) {
180 			pr_err(gettext("%s: is busy\n"), pathname);
181 		} else {
182 			pr_err(gettext("%s: not mounted\n"), pathname);
183 		}
184 		return (RET_ERR);
185 	}
186 
187 	/* All done if it's v4 */
188 	if (is_v4 == TRUE)
189 		return (RET_OK);
190 
191 	/* Inform server quickly in case of forced unmount */
192 	if (umnt_flag & MS_FORCE)
193 		quick = TRUE;
194 
195 	if (mntp) {
196 		inform_server(mntp->mnt_special, mntp->mnt_mntopts, quick);
197 	}
198 
199 	return (RET_OK);
200 }
201 
202 /*
203  *  Find the mnttab entry that corresponds to "name".
204  *  We're not sure what the name represents: either
205  *  a mountpoint name, or a special name (server:/path).
206  *  Return the last entry in the file that matches.
207  */
208 static struct extmnttab *
mnttab_find(dirname)209 mnttab_find(dirname)
210 	char *dirname;
211 {
212 	FILE *fp;
213 	struct extmnttab mnt;
214 	struct extmnttab *res = NULL;
215 
216 	fp = fopen(MNTTAB, "r");
217 	if (fp == NULL) {
218 		pr_err("%s: %s\n", MNTTAB, strerror(errno));
219 		return (NULL);
220 	}
221 	while (getextmntent(fp, &mnt, sizeof (struct extmnttab)) == 0) {
222 		if (strcmp(mnt.mnt_mountp, dirname) == 0 ||
223 		    strcmp(mnt.mnt_special, dirname) == 0) {
224 			if (res)
225 				fsfreemnttab(res);
226 			res = fsdupmnttab(&mnt);
227 		}
228 	}
229 
230 	(void) fclose(fp);
231 	return (res);
232 }
233 
234 /*
235  * If quick is TRUE, it will try to inform server quickly
236  * as possible.
237  */
238 static void
inform_server(char * string,char * opts,bool_t quick)239 inform_server(char *string, char *opts, bool_t quick)
240 {
241 	struct timeval timeout;
242 	CLIENT *cl;
243 	enum clnt_stat rpc_stat;
244 	struct replica *list;
245 	int i, n;
246 	char *p = NULL;
247 	static struct timeval create_timeout = {5, 0};
248 	static struct timeval *timep;
249 
250 	list = parse_replica(string, &n);
251 
252 	if (list == NULL) {
253 		if (n < 0)
254 			pr_err(gettext("%s is not hostname:path format\n"),
255 			    string);
256 		else
257 			pr_err(gettext("no memory\n"));
258 		return;
259 	}
260 
261 	/*
262 	 * If mounted with -o public, then no need to contact server
263 	 * because mount protocol was not used.
264 	 */
265 	if (opts != NULL)
266 		p = strstr(opts, MNTOPT_PUBLIC);
267 
268 	if (p != NULL) {
269 		i = strlen(MNTOPT_PUBLIC);
270 		/*
271 		 * Now make sure the match of "public" isn't a substring
272 		 * of another option.
273 		 */
274 		if (((p == opts) || (*(p-1) == ',')) &&
275 		    ((p[i] == ',') || (p[i] == '\0')))
276 			return;
277 	}
278 
279 	for (i = 0; i < n; i++) {
280 		int vers;
281 
282 		/*
283 		 * Skip file systems mounted using WebNFS, because mount
284 		 * protocol was not used.
285 		 */
286 		if (strcmp(list[i].host, "nfs") == 0 && strncmp(list[i].path,
287 		    "//", 2) == 0)
288 			continue;
289 
290 		vers =  MOUNTVERS;
291 retry:
292 		/*
293 		 * Use 5 sec. timeout if file system is forced unmounted,
294 		 * otherwise use default timeout to create a client handle.
295 		 * This would minimize the time to force unmount a file
296 		 * system reside on a server that is down.
297 		 */
298 		timep = (quick ? &create_timeout : NULL);
299 		cl = clnt_create_timed(list[i].host, MOUNTPROG, vers,
300 		    "datagram_n", timep);
301 		/*
302 		 * Do not print any error messages in case of forced
303 		 * unmount.
304 		 */
305 		if (cl == NULL) {
306 			if (!quick)
307 				pr_err("%s:%s %s\n", list[i].host, list[i].path,
308 				    clnt_spcreateerror(
309 				    "server not responding"));
310 			continue;
311 		}
312 		/*
313 		 * Now it is most likely that the NFS client will be able
314 		 * to contact the server since rpcbind is running on
315 		 * the server. There is still a small window in which
316 		 * server can be unreachable.
317 		 */
318 
319 		if (__clnt_bindresvport(cl) < 0) {
320 			if (!quick)
321 				pr_err(gettext(
322 				    "couldn't bind to reserved port\n"));
323 			clnt_destroy(cl);
324 			return;
325 		}
326 		if ((cl->cl_auth = authsys_create_default()) == NULL) {
327 			if (!quick)
328 				pr_err(gettext(
329 				    "couldn't create authsys structure\n"));
330 			clnt_destroy(cl);
331 			return;
332 		}
333 		timeout.tv_usec = 0;
334 		timeout.tv_sec = 5;
335 		clnt_control(cl, CLSET_RETRY_TIMEOUT, (char *)&timeout);
336 		timeout.tv_sec = 25;
337 		rpc_stat = clnt_call(cl, MOUNTPROC_UMNT, xdr_dirpath,
338 		    (char *)&list[i].path, xdr_void, (char *)NULL,
339 		    timeout);
340 		AUTH_DESTROY(cl->cl_auth);
341 		clnt_destroy(cl);
342 		if (rpc_stat == RPC_PROGVERSMISMATCH && vers == MOUNTVERS) {
343 			/*
344 			 * The rare case of a v3-only server
345 			 */
346 			vers = MOUNTVERS3;
347 			goto retry;
348 		}
349 		if (rpc_stat != RPC_SUCCESS)
350 			pr_err("%s\n", clnt_sperror(cl, "unmount"));
351 	}
352 
353 	free_replica(list, n);
354 }
355 
356 /*
357  * This function's behavior is taken from nfsstat.
358  * Trying to determine what NFS version was used for the mount.
359  */
360 int
is_v4_mount(struct extmnttab * mntp)361 is_v4_mount(struct extmnttab *mntp)
362 {
363 	kstat_ctl_t *kc = NULL;		/* libkstat cookie */
364 	kstat_t *ksp;
365 	struct mntinfo_kstat mik;
366 
367 	if (mntp == NULL)
368 		return (FALSE);
369 
370 	if ((kc = kstat_open()) == NULL)
371 		return (FALSE);
372 
373 	for (ksp = kc->kc_chain; ksp; ksp = ksp->ks_next) {
374 		if (ksp->ks_type != KSTAT_TYPE_RAW)
375 			continue;
376 		if (strcmp(ksp->ks_module, "nfs") != 0)
377 			continue;
378 		if (strcmp(ksp->ks_name, "mntinfo") != 0)
379 			continue;
380 		if (mntp->mnt_minor != ksp->ks_instance)
381 			continue;
382 
383 		if (kstat_read(kc, ksp, &mik) == -1)
384 			continue;
385 
386 		if (mik.mik_vers == 4)
387 			return (TRUE);
388 		else
389 			return (FALSE);
390 	}
391 	return (FALSE);
392 }
393