xref: /illumos-gate/usr/src/cmd/fs.d/nfs/umount/umount.c (revision 7c478bd9)
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, Version 1.0 only
6  * (the "License").  You may not use this file except in compliance
7  * with the License.
8  *
9  * You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE
10  * or http://www.opensolaris.org/os/licensing.
11  * See the License for the specific language governing permissions
12  * and limitations under the License.
13  *
14  * When distributing Covered Code, include this CDDL HEADER in each
15  * file and include the License file at usr/src/OPENSOLARIS.LICENSE.
16  * If applicable, add the following below this CDDL HEADER, with the
17  * fields enclosed by brackets "[]" replaced with your own identifying
18  * information: Portions Copyright [yyyy] [name of copyright owner]
19  *
20  * CDDL HEADER END
21  */
22 /*
23  * Copyright 2004 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 "replica.h"
65 
66 #define	RET_OK	0
67 #define	RET_ERR	32
68 
69 #ifdef __STDC__
70 static void pr_err(const char *fmt, ...);
71 #else
72 static void pr_err(char *fmt, va_dcl);
73 #endif
74 static	void	usage();
75 static	int	nfs_unmount(char *, int);
76 static	void	inform_server(char *, char *, bool_t);
77 static	struct extmnttab *mnttab_find();
78 extern int __clnt_bindresvport();
79 
80 static	int is_v4_mount(struct extmnttab *);
81 
82 static char *myname;
83 static char typename[64];
84 
85 main(argc, argv)
86 	int argc;
87 	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) sprintf(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 	 * exit, really
131 	 */
132 	return (nfs_unmount(argv[optind], umnt_flag));
133 }
134 
135 static void
136 pr_err(const char *fmt, ...)
137 {
138 	va_list ap;
139 
140 	va_start(ap, fmt);
141 	(void) fprintf(stderr, "%s: ", typename);
142 	(void) vfprintf(stderr, fmt, ap);
143 	(void) fflush(stderr);
144 	va_end(ap);
145 }
146 
147 static void
148 usage()
149 {
150 	(void) fprintf(stderr,
151 	    gettext("Usage: nfs umount [-o opts] {server:path | dir}\n"));
152 	exit(RET_ERR);
153 }
154 
155 static int
156 nfs_unmount(char *pathname, int umnt_flag)
157 {
158 	struct extmnttab *mntp;
159 	bool_t quick = FALSE;
160 	int is_v4 = FALSE;
161 
162 	mntp = mnttab_find(pathname);
163 	if (mntp) {
164 		pathname = mntp->mnt_mountp;
165 	}
166 
167 	if (mntp)
168 		is_v4 = is_v4_mount(mntp);
169 
170 	/* Forced unmount will almost always be successful */
171 	if (umount2(pathname, umnt_flag) < 0) {
172 		if (errno == EBUSY) {
173 			pr_err(gettext("%s: is busy\n"), pathname);
174 		} else {
175 			pr_err(gettext("%s: not mounted\n"), pathname);
176 		}
177 		return (RET_ERR);
178 	}
179 
180 	/* All done if it's v4 */
181 	if (is_v4 == TRUE)
182 		return (RET_OK);
183 
184 	/* Inform server quickly in case of forced unmount */
185 	if (umnt_flag & MS_FORCE)
186 		quick = TRUE;
187 
188 	if (mntp) {
189 		inform_server(mntp->mnt_special, mntp->mnt_mntopts, quick);
190 	}
191 
192 	return (RET_OK);
193 }
194 
195 /*
196  *  Find the mnttab entry that corresponds to "name".
197  *  We're not sure what the name represents: either
198  *  a mountpoint name, or a special name (server:/path).
199  *  Return the last entry in the file that matches.
200  */
201 static struct extmnttab *
202 mnttab_find(dirname)
203 	char *dirname;
204 {
205 	FILE *fp;
206 	struct extmnttab mnt;
207 	struct extmnttab *res = NULL;
208 
209 	fp = fopen(MNTTAB, "r");
210 	if (fp == NULL) {
211 		pr_err("%s: %s\n", MNTTAB, strerror(errno));
212 		return (NULL);
213 	}
214 	while (getextmntent(fp, &mnt, sizeof (struct extmnttab)) == 0) {
215 		if (strcmp(mnt.mnt_mountp, dirname) == 0 ||
216 		    strcmp(mnt.mnt_special, dirname) == 0) {
217 			if (res)
218 				fsfreemnttab(res);
219 			res = fsdupmnttab(&mnt);
220 		}
221 	}
222 
223 	fclose(fp);
224 	return (res);
225 }
226 
227 /*
228  * If quick is TRUE, it will try to inform server quickly
229  * as possible.
230  */
231 static void
232 inform_server(char *string, char *opts, bool_t quick)
233 {
234 	struct timeval timeout;
235 	CLIENT *cl;
236 	enum clnt_stat rpc_stat;
237 	struct replica *list;
238 	int i, n;
239 	char *p = NULL;
240 	static struct timeval create_timeout = {5, 0};
241 	static struct timeval *timep;
242 
243 	list = parse_replica(string, &n);
244 
245 	if (list == NULL) {
246 		if (n < 0)
247 			pr_err(gettext("%s is not hostname:path format\n"),
248 				string);
249 		else
250 			pr_err(gettext("no memory\n"));
251 		return;
252 	}
253 
254 	/*
255 	 * If mounted with -o public, then no need to contact server
256 	 * because mount protocol was not used.
257 	 */
258 	if (opts != NULL)
259 		p = strstr(opts, MNTOPT_PUBLIC);
260 
261 	if (p != NULL) {
262 		i = strlen(MNTOPT_PUBLIC);
263 		/*
264 		 * Now make sure the match of "public" isn't a substring
265 		 * of another option.
266 		 */
267 		if (((p == opts) || (*(p-1) == ',')) &&
268 		    ((p[i] == ',') || (p[i] == '\0')))
269 			return;
270 	}
271 
272 	for (i = 0; i < n; i++) {
273 		int vers;
274 
275 		/*
276 		 * Skip file systems mounted using WebNFS, because mount
277 		 * protocol was not used.
278 		 */
279 		if (strcmp(list[i].host, "nfs") == 0 && strncmp(list[i].path,
280 		    "//", 2) == 0)
281 			continue;
282 
283 		vers =  MOUNTVERS;
284 retry:
285 		/*
286 		 * Use 5 sec. timeout if file system is forced unmounted,
287 		 * otherwise use default timeout to create a client handle.
288 		 * This would minimize the time to force unmount a file
289 		 * system reside on a server that is down.
290 		 */
291 		timep = (quick ? &create_timeout : NULL);
292 		cl = clnt_create_timed(list[i].host, MOUNTPROG, vers,
293 				"datagram_n", timep);
294 		/*
295 		 * Do not print any error messages in case of forced
296 		 * unmount.
297 		 */
298 		if (cl == NULL) {
299 			if (!quick)
300 				pr_err("%s:%s %s\n", list[i].host, list[i].path,
301 				    clnt_spcreateerror(
302 					"server not responding"));
303 			continue;
304 		}
305 		/*
306 		 * Now it is most likely that the NFS client will be able
307 		 * to contact the server since rpcbind is running on
308 		 * the server. There is still a small window in which
309 		 * server can be unreachable.
310 		 */
311 
312 		if (__clnt_bindresvport(cl) < 0) {
313 			if (!quick)
314 				pr_err(gettext(
315 				    "couldn't bind to reserved port\n"));
316 			clnt_destroy(cl);
317 			return;
318 		}
319 		if ((cl->cl_auth = authsys_create_default()) == NULL) {
320 			if (!quick)
321 				pr_err(gettext(
322 				    "couldn't create authsys structure\n"));
323 			clnt_destroy(cl);
324 			return;
325 		}
326 		timeout.tv_usec = 0;
327 		timeout.tv_sec = 5;
328 		clnt_control(cl, CLSET_RETRY_TIMEOUT, (char *)&timeout);
329 		timeout.tv_sec = 25;
330 		rpc_stat = clnt_call(cl, MOUNTPROC_UMNT, xdr_dirpath,
331 			(char *)&list[i].path, xdr_void, (char *)NULL,
332 			timeout);
333 		AUTH_DESTROY(cl->cl_auth);
334 		clnt_destroy(cl);
335 		if (rpc_stat == RPC_PROGVERSMISMATCH && vers == MOUNTVERS) {
336 			/*
337 			 * The rare case of a v3-only server
338 			 */
339 			vers = MOUNTVERS3;
340 			goto retry;
341 		}
342 		if (rpc_stat != RPC_SUCCESS)
343 			pr_err("%s\n", clnt_sperror(cl, "unmount"));
344 	}
345 
346 	free_replica(list, n);
347 }
348 
349 /*
350  * This function's behavior is taken from nfsstat.
351  * Trying to determine what NFS version was used for the mount.
352  */
353 int
354 is_v4_mount(struct extmnttab *mntp)
355 {
356 	kstat_ctl_t *kc = NULL;		/* libkstat cookie */
357 	kstat_t *ksp;
358 	ulong_t fsid;
359 	struct mntinfo_kstat mik;
360 
361 	if (mntp == NULL)
362 		return (FALSE);
363 
364 	if ((kc = kstat_open()) == NULL)
365 		return (FALSE);
366 
367 	for (ksp = kc->kc_chain; ksp; ksp = ksp->ks_next) {
368 		if (ksp->ks_type != KSTAT_TYPE_RAW)
369 			continue;
370 		if (strcmp(ksp->ks_module, "nfs") != 0)
371 			continue;
372 		if (strcmp(ksp->ks_name, "mntinfo") != 0)
373 			continue;
374 		if (mntp->mnt_minor != ksp->ks_instance)
375 			continue;
376 
377 		if (kstat_read(kc, ksp, &mik) == -1)
378 			continue;
379 
380 		if (mik.mik_vers == 4)
381 			return (TRUE);
382 		else
383 			return (FALSE);
384 	}
385 	return (FALSE);
386 }
387