xref: /freebsd/usr.sbin/autofs/automount.c (revision dd41de95a84d979615a2ef11df6850622bf6184e)
1 /*-
2  * SPDX-License-Identifier: BSD-2-Clause-FreeBSD
3  *
4  * Copyright (c) 2014 The FreeBSD Foundation
5  *
6  * This software was developed by Edward Tomasz Napierala under sponsorship
7  * from the FreeBSD Foundation.
8  *
9  * Redistribution and use in source and binary forms, with or without
10  * modification, are permitted provided that the following conditions
11  * are met:
12  * 1. Redistributions of source code must retain the above copyright
13  *    notice, this list of conditions and the following disclaimer.
14  * 2. Redistributions in binary form must reproduce the above copyright
15  *    notice, this list of conditions and the following disclaimer in the
16  *    documentation and/or other materials provided with the distribution.
17  *
18  * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
19  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
20  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
21  * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
22  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
23  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
24  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
25  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
26  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
27  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
28  * SUCH DAMAGE.
29  *
30  */
31 
32 #include <sys/cdefs.h>
33 __FBSDID("$FreeBSD$");
34 
35 #include <sys/types.h>
36 #include <sys/time.h>
37 #include <sys/ioctl.h>
38 #include <sys/param.h>
39 #include <sys/linker.h>
40 #include <sys/mount.h>
41 #include <sys/socket.h>
42 #include <sys/stat.h>
43 #include <sys/wait.h>
44 #include <sys/utsname.h>
45 #include <assert.h>
46 #include <ctype.h>
47 #include <errno.h>
48 #include <fcntl.h>
49 #include <libgen.h>
50 #include <libutil.h>
51 #include <netdb.h>
52 #include <signal.h>
53 #include <stdbool.h>
54 #include <stdint.h>
55 #include <stdio.h>
56 #include <stdlib.h>
57 #include <string.h>
58 #include <unistd.h>
59 
60 #include "common.h"
61 #include "mntopts.h"
62 
63 static int
64 unmount_by_statfs(const struct statfs *sb, bool force)
65 {
66 	char *fsid_str;
67 	int error, ret, flags;
68 
69 	ret = asprintf(&fsid_str, "FSID:%d:%d",
70 	    sb->f_fsid.val[0], sb->f_fsid.val[1]);
71 	if (ret < 0)
72 		log_err(1, "asprintf");
73 
74 	log_debugx("unmounting %s using %s", sb->f_mntonname, fsid_str);
75 
76 	flags = MNT_BYFSID;
77 	if (force)
78 		flags |= MNT_FORCE;
79 	error = unmount(fsid_str, flags);
80 	free(fsid_str);
81 	if (error != 0)
82 		log_warn("cannot unmount %s", sb->f_mntonname);
83 	else
84 		rpc_umntall();
85 
86 	return (error);
87 }
88 
89 static const struct statfs *
90 find_statfs(const struct statfs *mntbuf, int nitems, const char *mountpoint)
91 {
92 	int i;
93 
94 	for (i = 0; i < nitems; i++) {
95 		if (strcmp(mntbuf[i].f_mntonname, mountpoint) == 0)
96 			return (mntbuf + i);
97 	}
98 
99 	return (NULL);
100 }
101 
102 static void
103 mount_autofs(const char *from, const char *fspath, const char *options,
104     const char *prefix)
105 {
106 	struct iovec *iov = NULL;
107 	char errmsg[255];
108 	int error, iovlen = 0;
109 
110 	create_directory(fspath);
111 
112 	log_debugx("mounting %s on %s, prefix \"%s\", options \"%s\"",
113 	    from, fspath, prefix, options);
114 	memset(errmsg, 0, sizeof(errmsg));
115 
116 	build_iovec(&iov, &iovlen, "fstype",
117 	    __DECONST(void *, "autofs"), (size_t)-1);
118 	build_iovec(&iov, &iovlen, "fspath",
119 	    __DECONST(void *, fspath), (size_t)-1);
120 	build_iovec(&iov, &iovlen, "from",
121 	    __DECONST(void *, from), (size_t)-1);
122 	build_iovec(&iov, &iovlen, "errmsg",
123 	    errmsg, sizeof(errmsg));
124 
125 	/*
126 	 * Append the options and mountpoint defined in auto_master(5);
127 	 * this way automountd(8) does not need to parse it.
128 	 */
129 	build_iovec(&iov, &iovlen, "master_options",
130 	    __DECONST(void *, options), (size_t)-1);
131 	build_iovec(&iov, &iovlen, "master_prefix",
132 	    __DECONST(void *, prefix), (size_t)-1);
133 
134 	error = nmount(iov, iovlen, 0);
135 	if (error != 0) {
136 		if (*errmsg != '\0') {
137 			log_err(1, "cannot mount %s on %s: %s",
138 			    from, fspath, errmsg);
139 		} else {
140 			log_err(1, "cannot mount %s on %s", from, fspath);
141 		}
142 	}
143 }
144 
145 static void
146 mount_if_not_already(const struct node *n, const char *map, const char *options,
147     const char *prefix, const struct statfs *mntbuf, int nitems)
148 {
149 	const struct statfs *sb;
150 	char *mountpoint;
151 	char *from;
152 	int ret;
153 
154 	ret = asprintf(&from, "map %s", map);
155 	if (ret < 0)
156 		log_err(1, "asprintf");
157 
158 	mountpoint = node_path(n);
159 	sb = find_statfs(mntbuf, nitems, mountpoint);
160 	if (sb != NULL) {
161 		if (strcmp(sb->f_fstypename, "autofs") != 0) {
162 			log_debugx("unknown filesystem mounted "
163 			    "on %s; mounting", mountpoint);
164 			/*
165 			 * XXX: Compare options and 'from',
166 			 *	and update the mount if necessary.
167 			 */
168 		} else {
169 			log_debugx("autofs already mounted "
170 			    "on %s", mountpoint);
171 			free(from);
172 			free(mountpoint);
173 			return;
174 		}
175 	} else {
176 		log_debugx("nothing mounted on %s; mounting",
177 		    mountpoint);
178 	}
179 
180 	mount_autofs(from, mountpoint, options, prefix);
181 	free(from);
182 	free(mountpoint);
183 }
184 
185 static void
186 mount_unmount(struct node *root)
187 {
188 	struct statfs *mntbuf;
189 	struct node *n, *n2;
190 	int i, nitems;
191 
192 	nitems = getmntinfo(&mntbuf, MNT_WAIT);
193 	if (nitems <= 0)
194 		log_err(1, "getmntinfo");
195 
196 	log_debugx("unmounting stale autofs mounts");
197 
198 	for (i = 0; i < nitems; i++) {
199 		if (strcmp(mntbuf[i].f_fstypename, "autofs") != 0) {
200 			log_debugx("skipping %s, filesystem type is not autofs",
201 			    mntbuf[i].f_mntonname);
202 			continue;
203 		}
204 
205 		n = node_find(root, mntbuf[i].f_mntonname);
206 		if (n != NULL) {
207 			log_debugx("leaving autofs mounted on %s",
208 			    mntbuf[i].f_mntonname);
209 			continue;
210 		}
211 
212 		log_debugx("autofs mounted on %s not found "
213 		    "in new configuration; unmounting", mntbuf[i].f_mntonname);
214 		unmount_by_statfs(&(mntbuf[i]), false);
215 	}
216 
217 	log_debugx("mounting new autofs mounts");
218 
219 	TAILQ_FOREACH(n, &root->n_children, n_next) {
220 		if (!node_is_direct_map(n)) {
221 			mount_if_not_already(n, n->n_map, n->n_options,
222 			    n->n_key, mntbuf, nitems);
223 			continue;
224 		}
225 
226 		TAILQ_FOREACH(n2, &n->n_children, n_next) {
227 			mount_if_not_already(n2, n->n_map, n->n_options,
228 			    "/", mntbuf, nitems);
229 		}
230 	}
231 }
232 
233 static void
234 flush_autofs(const char *fspath)
235 {
236 	struct iovec *iov = NULL;
237 	char errmsg[255];
238 	int error, iovlen = 0;
239 
240 	log_debugx("flushing %s", fspath);
241 	memset(errmsg, 0, sizeof(errmsg));
242 
243 	build_iovec(&iov, &iovlen, "fstype",
244 	    __DECONST(void *, "autofs"), (size_t)-1);
245 	build_iovec(&iov, &iovlen, "fspath",
246 	    __DECONST(void *, fspath), (size_t)-1);
247 	build_iovec(&iov, &iovlen, "errmsg",
248 	    errmsg, sizeof(errmsg));
249 
250 	error = nmount(iov, iovlen, MNT_UPDATE);
251 	if (error != 0) {
252 		if (*errmsg != '\0') {
253 			log_err(1, "cannot flush %s: %s",
254 			    fspath, errmsg);
255 		} else {
256 			log_err(1, "cannot flush %s", fspath);
257 		}
258 	}
259 }
260 
261 static void
262 flush_caches(void)
263 {
264 	struct statfs *mntbuf;
265 	int i, nitems;
266 
267 	nitems = getmntinfo(&mntbuf, MNT_WAIT);
268 	if (nitems <= 0)
269 		log_err(1, "getmntinfo");
270 
271 	log_debugx("flushing autofs caches");
272 
273 	for (i = 0; i < nitems; i++) {
274 		if (strcmp(mntbuf[i].f_fstypename, "autofs") != 0) {
275 			log_debugx("skipping %s, filesystem type is not autofs",
276 			    mntbuf[i].f_mntonname);
277 			continue;
278 		}
279 
280 		flush_autofs(mntbuf[i].f_mntonname);
281 	}
282 }
283 
284 static void
285 unmount_automounted(bool force)
286 {
287 	struct statfs *mntbuf;
288 	int i, nitems;
289 
290 	nitems = getmntinfo(&mntbuf, MNT_WAIT);
291 	if (nitems <= 0)
292 		log_err(1, "getmntinfo");
293 
294 	log_debugx("unmounting automounted filesystems");
295 
296 	for (i = 0; i < nitems; i++) {
297 		if (strcmp(mntbuf[i].f_fstypename, "autofs") == 0) {
298 			log_debugx("skipping %s, filesystem type is autofs",
299 			    mntbuf[i].f_mntonname);
300 			continue;
301 		}
302 
303 		if ((mntbuf[i].f_flags & MNT_AUTOMOUNTED) == 0) {
304 			log_debugx("skipping %s, not automounted",
305 			    mntbuf[i].f_mntonname);
306 			continue;
307 		}
308 
309 		unmount_by_statfs(&(mntbuf[i]), force);
310 	}
311 }
312 
313 static void
314 usage_automount(void)
315 {
316 
317 	fprintf(stderr, "usage: automount [-D name=value][-o opts][-Lcfuv]\n");
318 	exit(1);
319 }
320 
321 int
322 main_automount(int argc, char **argv)
323 {
324 	struct node *root;
325 	int ch, debug = 0, show_maps = 0;
326 	char *options = NULL;
327 	bool do_unmount = false, force_unmount = false, flush = false;
328 
329 	/*
330 	 * Note that in automount(8), the only purpose of variable
331 	 * handling is to aid in debugging maps (automount -L).
332 	 */
333 	defined_init();
334 
335 	while ((ch = getopt(argc, argv, "D:Lfco:uv")) != -1) {
336 		switch (ch) {
337 		case 'D':
338 			defined_parse_and_add(optarg);
339 			break;
340 		case 'L':
341 			show_maps++;
342 			break;
343 		case 'c':
344 			flush = true;
345 			break;
346 		case 'f':
347 			force_unmount = true;
348 			break;
349 		case 'o':
350 			options = concat(options, ',', optarg);
351 			break;
352 		case 'u':
353 			do_unmount = true;
354 			break;
355 		case 'v':
356 			debug++;
357 			break;
358 		case '?':
359 		default:
360 			usage_automount();
361 		}
362 	}
363 	argc -= optind;
364 	if (argc != 0)
365 		usage_automount();
366 
367 	if (force_unmount && !do_unmount)
368 		usage_automount();
369 
370 	log_init(debug);
371 
372 	if (flush) {
373 		flush_caches();
374 		return (0);
375 	}
376 
377 	if (do_unmount) {
378 		unmount_automounted(force_unmount);
379 		return (0);
380 	}
381 
382 	root = node_new_root();
383 	parse_master(root, AUTO_MASTER_PATH);
384 
385 	if (show_maps) {
386 		if (show_maps > 1) {
387 			node_expand_indirect_maps(root);
388 			node_expand_ampersand(root, NULL);
389 		}
390 		node_expand_defined(root);
391 		node_print(root, options);
392 		return (0);
393 	}
394 
395 	mount_unmount(root);
396 
397 	return (0);
398 }
399