xref: /freebsd/usr.sbin/autofs/automount.c (revision 22cf89c938886d14f5796fc49f9f020c23ea8eaf)
1 /*-
2  * SPDX-License-Identifier: BSD-2-Clause
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 #include <sys/types.h>
34 #include <sys/time.h>
35 #include <sys/ioctl.h>
36 #include <sys/param.h>
37 #include <sys/linker.h>
38 #include <sys/mount.h>
39 #include <sys/socket.h>
40 #include <sys/stat.h>
41 #include <sys/wait.h>
42 #include <sys/utsname.h>
43 #include <assert.h>
44 #include <ctype.h>
45 #include <errno.h>
46 #include <fcntl.h>
47 #include <libgen.h>
48 #include <libutil.h>
49 #include <netdb.h>
50 #include <signal.h>
51 #include <stdbool.h>
52 #include <stdint.h>
53 #include <stdio.h>
54 #include <stdlib.h>
55 #include <string.h>
56 #include <unistd.h>
57 
58 #include "common.h"
59 #include "mntopts.h"
60 
61 static int
62 unmount_by_statfs(const struct statfs *sb, bool force)
63 {
64 	char *fsid_str;
65 	int error, ret, flags;
66 
67 	ret = asprintf(&fsid_str, "FSID:%d:%d",
68 	    sb->f_fsid.val[0], sb->f_fsid.val[1]);
69 	if (ret < 0)
70 		log_err(1, "asprintf");
71 
72 	log_debugx("unmounting %s using %s", sb->f_mntonname, fsid_str);
73 
74 	flags = MNT_BYFSID;
75 	if (force)
76 		flags |= MNT_FORCE;
77 	error = unmount(fsid_str, flags);
78 	free(fsid_str);
79 	if (error != 0)
80 		log_warn("cannot unmount %s", sb->f_mntonname);
81 	else
82 		rpc_umntall();
83 
84 	return (error);
85 }
86 
87 static const struct statfs *
88 find_statfs(const struct statfs *mntbuf, int nitems, const char *mountpoint)
89 {
90 	int i;
91 
92 	for (i = 0; i < nitems; i++) {
93 		if (strcmp(mntbuf[i].f_mntonname, mountpoint) == 0)
94 			return (mntbuf + i);
95 	}
96 
97 	return (NULL);
98 }
99 
100 static void
101 mount_autofs(const char *from, const char *fspath, const char *options,
102     const char *prefix)
103 {
104 	struct iovec *iov = NULL;
105 	char errmsg[255];
106 	int error, iovlen = 0;
107 
108 	create_directory(fspath);
109 
110 	log_debugx("mounting %s on %s, prefix \"%s\", options \"%s\"",
111 	    from, fspath, prefix, options);
112 	memset(errmsg, 0, sizeof(errmsg));
113 
114 	build_iovec(&iov, &iovlen, "fstype",
115 	    __DECONST(void *, "autofs"), (size_t)-1);
116 	build_iovec(&iov, &iovlen, "fspath",
117 	    __DECONST(void *, fspath), (size_t)-1);
118 	build_iovec(&iov, &iovlen, "from",
119 	    __DECONST(void *, from), (size_t)-1);
120 	build_iovec(&iov, &iovlen, "errmsg",
121 	    errmsg, sizeof(errmsg));
122 
123 	/*
124 	 * Append the options and mountpoint defined in auto_master(5);
125 	 * this way automountd(8) does not need to parse it.
126 	 */
127 	build_iovec(&iov, &iovlen, "master_options",
128 	    __DECONST(void *, options), (size_t)-1);
129 	build_iovec(&iov, &iovlen, "master_prefix",
130 	    __DECONST(void *, prefix), (size_t)-1);
131 
132 	error = nmount(iov, iovlen, 0);
133 	if (error != 0) {
134 		if (*errmsg != '\0') {
135 			log_err(1, "cannot mount %s on %s: %s",
136 			    from, fspath, errmsg);
137 		} else {
138 			log_err(1, "cannot mount %s on %s", from, fspath);
139 		}
140 	}
141 }
142 
143 static void
144 mount_if_not_already(const struct node *n, const char *map, const char *options,
145     const char *prefix, const struct statfs *mntbuf, int nitems)
146 {
147 	const struct statfs *sb;
148 	char *mountpoint;
149 	char *from;
150 	int ret;
151 
152 	ret = asprintf(&from, "map %s", map);
153 	if (ret < 0)
154 		log_err(1, "asprintf");
155 
156 	mountpoint = node_path(n);
157 	sb = find_statfs(mntbuf, nitems, mountpoint);
158 	if (sb != NULL) {
159 		if (strcmp(sb->f_fstypename, "autofs") != 0) {
160 			log_debugx("unknown filesystem mounted "
161 			    "on %s; mounting", mountpoint);
162 			/*
163 			 * XXX: Compare options and 'from',
164 			 *	and update the mount if necessary.
165 			 */
166 		} else {
167 			log_debugx("autofs already mounted "
168 			    "on %s", mountpoint);
169 			free(from);
170 			free(mountpoint);
171 			return;
172 		}
173 	} else {
174 		log_debugx("nothing mounted on %s; mounting",
175 		    mountpoint);
176 	}
177 
178 	mount_autofs(from, mountpoint, options, prefix);
179 	free(from);
180 	free(mountpoint);
181 }
182 
183 static void
184 mount_unmount(struct node *root)
185 {
186 	struct statfs *mntbuf;
187 	struct node *n, *n2;
188 	int i, nitems;
189 
190 	nitems = getmntinfo(&mntbuf, MNT_WAIT);
191 	if (nitems <= 0)
192 		log_err(1, "getmntinfo");
193 
194 	log_debugx("unmounting stale autofs mounts");
195 
196 	for (i = 0; i < nitems; i++) {
197 		if (strcmp(mntbuf[i].f_fstypename, "autofs") != 0) {
198 			log_debugx("skipping %s, filesystem type is not autofs",
199 			    mntbuf[i].f_mntonname);
200 			continue;
201 		}
202 
203 		n = node_find(root, mntbuf[i].f_mntonname);
204 		if (n != NULL) {
205 			log_debugx("leaving autofs mounted on %s",
206 			    mntbuf[i].f_mntonname);
207 			continue;
208 		}
209 
210 		log_debugx("autofs mounted on %s not found "
211 		    "in new configuration; unmounting", mntbuf[i].f_mntonname);
212 		unmount_by_statfs(&(mntbuf[i]), false);
213 	}
214 
215 	log_debugx("mounting new autofs mounts");
216 
217 	TAILQ_FOREACH(n, &root->n_children, n_next) {
218 		if (!node_is_direct_map(n)) {
219 			mount_if_not_already(n, n->n_map, n->n_options,
220 			    n->n_key, mntbuf, nitems);
221 			continue;
222 		}
223 
224 		TAILQ_FOREACH(n2, &n->n_children, n_next) {
225 			mount_if_not_already(n2, n->n_map, n->n_options,
226 			    "/", mntbuf, nitems);
227 		}
228 	}
229 }
230 
231 static void
232 flush_autofs(const char *fspath)
233 {
234 	struct iovec *iov = NULL;
235 	char errmsg[255];
236 	int error, iovlen = 0;
237 
238 	log_debugx("flushing %s", fspath);
239 	memset(errmsg, 0, sizeof(errmsg));
240 
241 	build_iovec(&iov, &iovlen, "fstype",
242 	    __DECONST(void *, "autofs"), (size_t)-1);
243 	build_iovec(&iov, &iovlen, "fspath",
244 	    __DECONST(void *, fspath), (size_t)-1);
245 	build_iovec(&iov, &iovlen, "errmsg",
246 	    errmsg, sizeof(errmsg));
247 
248 	error = nmount(iov, iovlen, MNT_UPDATE);
249 	if (error != 0) {
250 		if (*errmsg != '\0') {
251 			log_err(1, "cannot flush %s: %s",
252 			    fspath, errmsg);
253 		} else {
254 			log_err(1, "cannot flush %s", fspath);
255 		}
256 	}
257 }
258 
259 static void
260 flush_caches(void)
261 {
262 	struct statfs *mntbuf;
263 	int i, nitems;
264 
265 	nitems = getmntinfo(&mntbuf, MNT_WAIT);
266 	if (nitems <= 0)
267 		log_err(1, "getmntinfo");
268 
269 	log_debugx("flushing autofs caches");
270 
271 	for (i = 0; i < nitems; i++) {
272 		if (strcmp(mntbuf[i].f_fstypename, "autofs") != 0) {
273 			log_debugx("skipping %s, filesystem type is not autofs",
274 			    mntbuf[i].f_mntonname);
275 			continue;
276 		}
277 
278 		flush_autofs(mntbuf[i].f_mntonname);
279 	}
280 }
281 
282 static void
283 unmount_automounted(bool force)
284 {
285 	struct statfs *mntbuf;
286 	int i, nitems;
287 
288 	nitems = getmntinfo(&mntbuf, MNT_WAIT);
289 	if (nitems <= 0)
290 		log_err(1, "getmntinfo");
291 
292 	log_debugx("unmounting automounted filesystems");
293 
294 	for (i = 0; i < nitems; i++) {
295 		if (strcmp(mntbuf[i].f_fstypename, "autofs") == 0) {
296 			log_debugx("skipping %s, filesystem type is autofs",
297 			    mntbuf[i].f_mntonname);
298 			continue;
299 		}
300 
301 		if ((mntbuf[i].f_flags & MNT_AUTOMOUNTED) == 0) {
302 			log_debugx("skipping %s, not automounted",
303 			    mntbuf[i].f_mntonname);
304 			continue;
305 		}
306 
307 		unmount_by_statfs(&(mntbuf[i]), force);
308 	}
309 }
310 
311 static void
312 usage_automount(void)
313 {
314 
315 	fprintf(stderr, "usage: automount [-D name=value][-o opts][-Lcfuv]\n");
316 	exit(1);
317 }
318 
319 int
320 main_automount(int argc, char **argv)
321 {
322 	struct node *root;
323 	int ch, debug = 0, show_maps = 0;
324 	char *options = NULL;
325 	bool do_unmount = false, force_unmount = false, flush = false;
326 
327 	/*
328 	 * Note that in automount(8), the only purpose of variable
329 	 * handling is to aid in debugging maps (automount -L).
330 	 */
331 	defined_init();
332 
333 	while ((ch = getopt(argc, argv, "D:Lfco:uv")) != -1) {
334 		switch (ch) {
335 		case 'D':
336 			defined_parse_and_add(optarg);
337 			break;
338 		case 'L':
339 			show_maps++;
340 			break;
341 		case 'c':
342 			flush = true;
343 			break;
344 		case 'f':
345 			force_unmount = true;
346 			break;
347 		case 'o':
348 			options = concat(options, ',', optarg);
349 			break;
350 		case 'u':
351 			do_unmount = true;
352 			break;
353 		case 'v':
354 			debug++;
355 			break;
356 		case '?':
357 		default:
358 			usage_automount();
359 		}
360 	}
361 	argc -= optind;
362 	if (argc != 0)
363 		usage_automount();
364 
365 	if (force_unmount && !do_unmount)
366 		usage_automount();
367 
368 	log_init(debug);
369 
370 	if (flush) {
371 		flush_caches();
372 		return (0);
373 	}
374 
375 	if (do_unmount) {
376 		unmount_automounted(force_unmount);
377 		return (0);
378 	}
379 
380 	root = node_new_root();
381 	parse_master(root, AUTO_MASTER_PATH);
382 
383 	if (show_maps) {
384 		if (show_maps > 1) {
385 			node_expand_indirect_maps(root);
386 			node_expand_ampersand(root, NULL);
387 		}
388 		node_expand_defined(root);
389 		node_print(root, options);
390 		return (0);
391 	}
392 
393 	mount_unmount(root);
394 
395 	return (0);
396 }
397