xref: /illumos-gate/usr/src/cmd/fs.d/nfs/umount/umount.c (revision 88f8b78a88cbdc6d8c1af5c3e54bc49d25095c98)
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 2005 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 int
86 main(int argc, char *argv[])
87 {
88 	extern int optind;
89 	int c;
90 	int umnt_flag = 0;
91 
92 	(void) setlocale(LC_ALL, "");
93 
94 #if !defined(TEXT_DOMAIN)
95 #define	TEXT_DOMAIN "SYS_TEST"
96 #endif
97 	(void) textdomain(TEXT_DOMAIN);
98 
99 	myname = strrchr(argv[0], '/');
100 	myname = myname ? myname+1 : argv[0];
101 	(void) sprintf(typename, "nfs %s", myname);
102 	argv[0] = typename;
103 
104 	/*
105 	 * Set options
106 	 */
107 	while ((c = getopt(argc, argv, "f")) != EOF) {
108 		switch (c) {
109 		case 'f':
110 			umnt_flag |= MS_FORCE; /* forced unmount is desired */
111 			break;
112 		default:
113 			usage();
114 			exit(RET_ERR);
115 		}
116 	}
117 	if (argc - optind != 1) {
118 		usage();
119 		exit(RET_ERR);
120 	}
121 
122 	if (!priv_ineffect(PRIV_SYS_MOUNT) ||
123 	    !priv_ineffect(PRIV_NET_PRIVADDR)) {
124 		pr_err(gettext("insufficient privileges\n"));
125 		exit(RET_ERR);
126 	}
127 
128 	/*
129 	 * exit, really
130 	 */
131 	return (nfs_unmount(argv[optind], umnt_flag));
132 }
133 
134 static void
135 pr_err(const char *fmt, ...)
136 {
137 	va_list ap;
138 
139 	va_start(ap, fmt);
140 	(void) fprintf(stderr, "%s: ", typename);
141 	(void) vfprintf(stderr, fmt, ap);
142 	(void) fflush(stderr);
143 	va_end(ap);
144 }
145 
146 static void
147 usage()
148 {
149 	(void) fprintf(stderr,
150 	    gettext("Usage: nfs umount [-o opts] {server:path | dir}\n"));
151 	exit(RET_ERR);
152 }
153 
154 static int
155 nfs_unmount(char *pathname, int umnt_flag)
156 {
157 	struct extmnttab *mntp;
158 	bool_t quick = FALSE;
159 	int is_v4 = FALSE;
160 
161 	mntp = mnttab_find(pathname);
162 	if (mntp) {
163 		pathname = mntp->mnt_mountp;
164 	}
165 
166 	if (mntp)
167 		is_v4 = is_v4_mount(mntp);
168 
169 	/* Forced unmount will almost always be successful */
170 	if (umount2(pathname, umnt_flag) < 0) {
171 		if (errno == EBUSY) {
172 			pr_err(gettext("%s: is busy\n"), pathname);
173 		} else {
174 			pr_err(gettext("%s: not mounted\n"), pathname);
175 		}
176 		return (RET_ERR);
177 	}
178 
179 	/* All done if it's v4 */
180 	if (is_v4 == TRUE)
181 		return (RET_OK);
182 
183 	/* Inform server quickly in case of forced unmount */
184 	if (umnt_flag & MS_FORCE)
185 		quick = TRUE;
186 
187 	if (mntp) {
188 		inform_server(mntp->mnt_special, mntp->mnt_mntopts, quick);
189 	}
190 
191 	return (RET_OK);
192 }
193 
194 /*
195  *  Find the mnttab entry that corresponds to "name".
196  *  We're not sure what the name represents: either
197  *  a mountpoint name, or a special name (server:/path).
198  *  Return the last entry in the file that matches.
199  */
200 static struct extmnttab *
201 mnttab_find(dirname)
202 	char *dirname;
203 {
204 	FILE *fp;
205 	struct extmnttab mnt;
206 	struct extmnttab *res = NULL;
207 
208 	fp = fopen(MNTTAB, "r");
209 	if (fp == NULL) {
210 		pr_err("%s: %s\n", MNTTAB, strerror(errno));
211 		return (NULL);
212 	}
213 	while (getextmntent(fp, &mnt, sizeof (struct extmnttab)) == 0) {
214 		if (strcmp(mnt.mnt_mountp, dirname) == 0 ||
215 		    strcmp(mnt.mnt_special, dirname) == 0) {
216 			if (res)
217 				fsfreemnttab(res);
218 			res = fsdupmnttab(&mnt);
219 		}
220 	}
221 
222 	fclose(fp);
223 	return (res);
224 }
225 
226 /*
227  * If quick is TRUE, it will try to inform server quickly
228  * as possible.
229  */
230 static void
231 inform_server(char *string, char *opts, bool_t quick)
232 {
233 	struct timeval timeout;
234 	CLIENT *cl;
235 	enum clnt_stat rpc_stat;
236 	struct replica *list;
237 	int i, n;
238 	char *p = NULL;
239 	static struct timeval create_timeout = {5, 0};
240 	static struct timeval *timep;
241 
242 	list = parse_replica(string, &n);
243 
244 	if (list == NULL) {
245 		if (n < 0)
246 			pr_err(gettext("%s is not hostname:path format\n"),
247 				string);
248 		else
249 			pr_err(gettext("no memory\n"));
250 		return;
251 	}
252 
253 	/*
254 	 * If mounted with -o public, then no need to contact server
255 	 * because mount protocol was not used.
256 	 */
257 	if (opts != NULL)
258 		p = strstr(opts, MNTOPT_PUBLIC);
259 
260 	if (p != NULL) {
261 		i = strlen(MNTOPT_PUBLIC);
262 		/*
263 		 * Now make sure the match of "public" isn't a substring
264 		 * of another option.
265 		 */
266 		if (((p == opts) || (*(p-1) == ',')) &&
267 		    ((p[i] == ',') || (p[i] == '\0')))
268 			return;
269 	}
270 
271 	for (i = 0; i < n; i++) {
272 		int vers;
273 
274 		/*
275 		 * Skip file systems mounted using WebNFS, because mount
276 		 * protocol was not used.
277 		 */
278 		if (strcmp(list[i].host, "nfs") == 0 && strncmp(list[i].path,
279 		    "//", 2) == 0)
280 			continue;
281 
282 		vers =  MOUNTVERS;
283 retry:
284 		/*
285 		 * Use 5 sec. timeout if file system is forced unmounted,
286 		 * otherwise use default timeout to create a client handle.
287 		 * This would minimize the time to force unmount a file
288 		 * system reside on a server that is down.
289 		 */
290 		timep = (quick ? &create_timeout : NULL);
291 		cl = clnt_create_timed(list[i].host, MOUNTPROG, vers,
292 				"datagram_n", timep);
293 		/*
294 		 * Do not print any error messages in case of forced
295 		 * unmount.
296 		 */
297 		if (cl == NULL) {
298 			if (!quick)
299 				pr_err("%s:%s %s\n", list[i].host, list[i].path,
300 				    clnt_spcreateerror(
301 					"server not responding"));
302 			continue;
303 		}
304 		/*
305 		 * Now it is most likely that the NFS client will be able
306 		 * to contact the server since rpcbind is running on
307 		 * the server. There is still a small window in which
308 		 * server can be unreachable.
309 		 */
310 
311 		if (__clnt_bindresvport(cl) < 0) {
312 			if (!quick)
313 				pr_err(gettext(
314 				    "couldn't bind to reserved port\n"));
315 			clnt_destroy(cl);
316 			return;
317 		}
318 		if ((cl->cl_auth = authsys_create_default()) == NULL) {
319 			if (!quick)
320 				pr_err(gettext(
321 				    "couldn't create authsys structure\n"));
322 			clnt_destroy(cl);
323 			return;
324 		}
325 		timeout.tv_usec = 0;
326 		timeout.tv_sec = 5;
327 		clnt_control(cl, CLSET_RETRY_TIMEOUT, (char *)&timeout);
328 		timeout.tv_sec = 25;
329 		rpc_stat = clnt_call(cl, MOUNTPROC_UMNT, xdr_dirpath,
330 			(char *)&list[i].path, xdr_void, (char *)NULL,
331 			timeout);
332 		AUTH_DESTROY(cl->cl_auth);
333 		clnt_destroy(cl);
334 		if (rpc_stat == RPC_PROGVERSMISMATCH && vers == MOUNTVERS) {
335 			/*
336 			 * The rare case of a v3-only server
337 			 */
338 			vers = MOUNTVERS3;
339 			goto retry;
340 		}
341 		if (rpc_stat != RPC_SUCCESS)
342 			pr_err("%s\n", clnt_sperror(cl, "unmount"));
343 	}
344 
345 	free_replica(list, n);
346 }
347 
348 /*
349  * This function's behavior is taken from nfsstat.
350  * Trying to determine what NFS version was used for the mount.
351  */
352 int
353 is_v4_mount(struct extmnttab *mntp)
354 {
355 	kstat_ctl_t *kc = NULL;		/* libkstat cookie */
356 	kstat_t *ksp;
357 	ulong_t fsid;
358 	struct mntinfo_kstat mik;
359 
360 	if (mntp == NULL)
361 		return (FALSE);
362 
363 	if ((kc = kstat_open()) == NULL)
364 		return (FALSE);
365 
366 	for (ksp = kc->kc_chain; ksp; ksp = ksp->ks_next) {
367 		if (ksp->ks_type != KSTAT_TYPE_RAW)
368 			continue;
369 		if (strcmp(ksp->ks_module, "nfs") != 0)
370 			continue;
371 		if (strcmp(ksp->ks_name, "mntinfo") != 0)
372 			continue;
373 		if (mntp->mnt_minor != ksp->ks_instance)
374 			continue;
375 
376 		if (kstat_read(kc, ksp, &mik) == -1)
377 			continue;
378 
379 		if (mik.mik_vers == 4)
380 			return (TRUE);
381 		else
382 			return (FALSE);
383 	}
384 	return (FALSE);
385 }
386