xref: /freebsd/usr.sbin/autofs/automount.c (revision 09a53ad8f1318c5daae6cfb19d97f4f6459f0013)
1 /*-
2  * Copyright (c) 2014 The FreeBSD Foundation
3  * All rights reserved.
4  *
5  * This software was developed by Edward Tomasz Napierala under sponsorship
6  * from the FreeBSD Foundation.
7  *
8  * Redistribution and use in source and binary forms, with or without
9  * modification, are permitted provided that the following conditions
10  * are met:
11  * 1. Redistributions of source code must retain the above copyright
12  *    notice, this list of conditions and the following disclaimer.
13  * 2. Redistributions in binary form must reproduce the above copyright
14  *    notice, this list of conditions and the following disclaimer in the
15  *    documentation and/or other materials provided with the distribution.
16  *
17  * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
18  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
19  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
20  * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
21  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
22  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
23  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
24  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
25  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
26  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
27  * SUCH DAMAGE.
28  *
29  */
30 
31 #include <sys/cdefs.h>
32 __FBSDID("$FreeBSD$");
33 
34 #include <sys/types.h>
35 #include <sys/time.h>
36 #include <sys/ioctl.h>
37 #include <sys/param.h>
38 #include <sys/linker.h>
39 #include <sys/mount.h>
40 #include <sys/socket.h>
41 #include <sys/stat.h>
42 #include <sys/wait.h>
43 #include <sys/utsname.h>
44 #include <assert.h>
45 #include <ctype.h>
46 #include <errno.h>
47 #include <fcntl.h>
48 #include <libgen.h>
49 #include <libutil.h>
50 #include <netdb.h>
51 #include <signal.h>
52 #include <stdbool.h>
53 #include <stdint.h>
54 #include <stdio.h>
55 #include <stdlib.h>
56 #include <string.h>
57 #include <unistd.h>
58 
59 #include "common.h"
60 #include "mntopts.h"
61 
62 static int
63 unmount_by_statfs(const struct statfs *sb, bool force)
64 {
65 	char *fsid_str;
66 	int error, ret, flags;
67 
68 	ret = asprintf(&fsid_str, "FSID:%d:%d",
69 	    sb->f_fsid.val[0], sb->f_fsid.val[1]);
70 	if (ret < 0)
71 		log_err(1, "asprintf");
72 
73 	log_debugx("unmounting %s using %s", sb->f_mntonname, fsid_str);
74 
75 	flags = MNT_BYFSID;
76 	if (force)
77 		flags |= MNT_FORCE;
78 	error = unmount(fsid_str, flags);
79 	free(fsid_str);
80 	if (error != 0)
81 		log_warn("cannot unmount %s", sb->f_mntonname);
82 
83 	return (error);
84 }
85 
86 static const struct statfs *
87 find_statfs(const struct statfs *mntbuf, int nitems, const char *mountpoint)
88 {
89 	int i;
90 
91 	for (i = 0; i < nitems; i++) {
92 		if (strcmp(mntbuf[i].f_mntonname, mountpoint) == 0)
93 			return (mntbuf + i);
94 	}
95 
96 	return (NULL);
97 }
98 
99 static void
100 mount_autofs(const char *from, const char *fspath, const char *options,
101     const char *prefix)
102 {
103 	struct iovec *iov = NULL;
104 	char errmsg[255];
105 	int error, iovlen = 0;
106 
107 	create_directory(fspath);
108 
109 	log_debugx("mounting %s on %s, prefix \"%s\", options \"%s\"",
110 	    from, fspath, prefix, options);
111 	memset(errmsg, 0, sizeof(errmsg));
112 
113 	build_iovec(&iov, &iovlen, "fstype",
114 	    __DECONST(void *, "autofs"), (size_t)-1);
115 	build_iovec(&iov, &iovlen, "fspath",
116 	    __DECONST(void *, fspath), (size_t)-1);
117 	build_iovec(&iov, &iovlen, "from",
118 	    __DECONST(void *, from), (size_t)-1);
119 	build_iovec(&iov, &iovlen, "errmsg",
120 	    errmsg, sizeof(errmsg));
121 
122 	/*
123 	 * Append the options and mountpoint defined in auto_master(5);
124 	 * this way automountd(8) does not need to parse it.
125 	 */
126 	build_iovec(&iov, &iovlen, "master_options",
127 	    __DECONST(void *, options), (size_t)-1);
128 	build_iovec(&iov, &iovlen, "master_prefix",
129 	    __DECONST(void *, prefix), (size_t)-1);
130 
131 	error = nmount(iov, iovlen, 0);
132 	if (error != 0) {
133 		if (*errmsg != '\0') {
134 			log_err(1, "cannot mount %s on %s: %s",
135 			    from, fspath, errmsg);
136 		} else {
137 			log_err(1, "cannot mount %s on %s", from, fspath);
138 		}
139 	}
140 }
141 
142 static void
143 mount_if_not_already(const struct node *n, const char *map, const char *options,
144     const char *prefix, const struct statfs *mntbuf, int nitems)
145 {
146 	const struct statfs *sb;
147 	char *mountpoint;
148 	char *from;
149 	int ret;
150 
151 	ret = asprintf(&from, "map %s", map);
152 	if (ret < 0)
153 		log_err(1, "asprintf");
154 
155 	mountpoint = node_path(n);
156 	sb = find_statfs(mntbuf, nitems, mountpoint);
157 	if (sb != NULL) {
158 		if (strcmp(sb->f_fstypename, "autofs") != 0) {
159 			log_debugx("unknown filesystem mounted "
160 			    "on %s; mounting", mountpoint);
161 			/*
162 			 * XXX: Compare options and 'from',
163 			 *	and update the mount if necessary.
164 			 */
165 		} else {
166 			log_debugx("autofs already mounted "
167 			    "on %s", mountpoint);
168 			free(from);
169 			free(mountpoint);
170 			return;
171 		}
172 	} else {
173 		log_debugx("nothing mounted on %s; mounting",
174 		    mountpoint);
175 	}
176 
177 	mount_autofs(from, mountpoint, options, prefix);
178 	free(from);
179 	free(mountpoint);
180 }
181 
182 static void
183 mount_unmount(struct node *root)
184 {
185 	struct statfs *mntbuf;
186 	struct node *n, *n2;
187 	int i, nitems;
188 
189 	nitems = getmntinfo(&mntbuf, MNT_WAIT);
190 	if (nitems <= 0)
191 		log_err(1, "getmntinfo");
192 
193 	log_debugx("unmounting stale autofs mounts");
194 
195 	for (i = 0; i < nitems; i++) {
196 		if (strcmp(mntbuf[i].f_fstypename, "autofs") != 0) {
197 			log_debugx("skipping %s, filesystem type is not autofs",
198 			    mntbuf[i].f_mntonname);
199 			continue;
200 		}
201 
202 		n = node_find(root, mntbuf[i].f_mntonname);
203 		if (n != NULL) {
204 			log_debugx("leaving autofs mounted on %s",
205 			    mntbuf[i].f_mntonname);
206 			continue;
207 		}
208 
209 		log_debugx("autofs mounted on %s not found "
210 		    "in new configuration; unmounting", mntbuf[i].f_mntonname);
211 		unmount_by_statfs(&(mntbuf[i]), false);
212 	}
213 
214 	log_debugx("mounting new autofs mounts");
215 
216 	TAILQ_FOREACH(n, &root->n_children, n_next) {
217 		if (!node_is_direct_map(n)) {
218 			mount_if_not_already(n, n->n_map, n->n_options,
219 			    n->n_key, mntbuf, nitems);
220 			continue;
221 		}
222 
223 		TAILQ_FOREACH(n2, &n->n_children, n_next) {
224 			mount_if_not_already(n2, n->n_map, n->n_options,
225 			    "/", mntbuf, nitems);
226 		}
227 	}
228 }
229 
230 static void
231 flush_autofs(const char *fspath)
232 {
233 	struct iovec *iov = NULL;
234 	char errmsg[255];
235 	int error, iovlen = 0;
236 
237 	log_debugx("flushing %s", fspath);
238 	memset(errmsg, 0, sizeof(errmsg));
239 
240 	build_iovec(&iov, &iovlen, "fstype",
241 	    __DECONST(void *, "autofs"), (size_t)-1);
242 	build_iovec(&iov, &iovlen, "fspath",
243 	    __DECONST(void *, fspath), (size_t)-1);
244 	build_iovec(&iov, &iovlen, "errmsg",
245 	    errmsg, sizeof(errmsg));
246 
247 	error = nmount(iov, iovlen, MNT_UPDATE);
248 	if (error != 0) {
249 		if (*errmsg != '\0') {
250 			log_err(1, "cannot flush %s: %s",
251 			    fspath, errmsg);
252 		} else {
253 			log_err(1, "cannot flush %s", fspath);
254 		}
255 	}
256 }
257 
258 static void
259 flush_caches(void)
260 {
261 	struct statfs *mntbuf;
262 	int i, nitems;
263 
264 	nitems = getmntinfo(&mntbuf, MNT_WAIT);
265 	if (nitems <= 0)
266 		log_err(1, "getmntinfo");
267 
268 	log_debugx("flushing autofs caches");
269 
270 	for (i = 0; i < nitems; i++) {
271 		if (strcmp(mntbuf[i].f_fstypename, "autofs") != 0) {
272 			log_debugx("skipping %s, filesystem type is not autofs",
273 			    mntbuf[i].f_mntonname);
274 			continue;
275 		}
276 
277 		flush_autofs(mntbuf[i].f_mntonname);
278 	}
279 }
280 
281 static void
282 unmount_automounted(bool force)
283 {
284 	struct statfs *mntbuf;
285 	int i, nitems;
286 
287 	nitems = getmntinfo(&mntbuf, MNT_WAIT);
288 	if (nitems <= 0)
289 		log_err(1, "getmntinfo");
290 
291 	log_debugx("unmounting automounted filesystems");
292 
293 	for (i = 0; i < nitems; i++) {
294 		if (strcmp(mntbuf[i].f_fstypename, "autofs") == 0) {
295 			log_debugx("skipping %s, filesystem type is autofs",
296 			    mntbuf[i].f_mntonname);
297 			continue;
298 		}
299 
300 		if ((mntbuf[i].f_flags & MNT_AUTOMOUNTED) == 0) {
301 			log_debugx("skipping %s, not automounted",
302 			    mntbuf[i].f_mntonname);
303 			continue;
304 		}
305 
306 		unmount_by_statfs(&(mntbuf[i]), force);
307 	}
308 }
309 
310 static void
311 usage_automount(void)
312 {
313 
314 	fprintf(stderr, "usage: automount [-D name=value][-o opts][-Lcfuv]\n");
315 	exit(1);
316 }
317 
318 int
319 main_automount(int argc, char **argv)
320 {
321 	struct node *root;
322 	int ch, debug = 0, show_maps = 0;
323 	char *options = NULL;
324 	bool do_unmount = false, force_unmount = false, flush = false;
325 
326 	/*
327 	 * Note that in automount(8), the only purpose of variable
328 	 * handling is to aid in debugging maps (automount -L).
329 	 */
330 	defined_init();
331 
332 	while ((ch = getopt(argc, argv, "D:Lfco:uv")) != -1) {
333 		switch (ch) {
334 		case 'D':
335 			defined_parse_and_add(optarg);
336 			break;
337 		case 'L':
338 			show_maps++;
339 			break;
340 		case 'c':
341 			flush = true;
342 			break;
343 		case 'f':
344 			force_unmount = true;
345 			break;
346 		case 'o':
347 			options = concat(options, ',', optarg);
348 			break;
349 		case 'u':
350 			do_unmount = true;
351 			break;
352 		case 'v':
353 			debug++;
354 			break;
355 		case '?':
356 		default:
357 			usage_automount();
358 		}
359 	}
360 	argc -= optind;
361 	if (argc != 0)
362 		usage_automount();
363 
364 	if (force_unmount && !do_unmount)
365 		usage_automount();
366 
367 	log_init(debug);
368 
369 	if (flush) {
370 		flush_caches();
371 		return (0);
372 	}
373 
374 	if (do_unmount) {
375 		unmount_automounted(force_unmount);
376 		return (0);
377 	}
378 
379 	root = node_new_root();
380 	parse_master(root, AUTO_MASTER_PATH);
381 
382 	if (show_maps) {
383 		if (show_maps > 1) {
384 			node_expand_indirect_maps(root);
385 			node_expand_ampersand(root, NULL);
386 		}
387 		node_expand_defined(root);
388 		node_print(root, options);
389 		return (0);
390 	}
391 
392 	mount_unmount(root);
393 
394 	return (0);
395 }
396