automount.c revision 283231 
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: stable/10/usr.sbin/autofs/automount.c 283231 2015-05-21 13:25:28Z trasz $");
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 <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 <libutil.h>
59
60#include "common.h"
61#include "mntopts.h"
62
63static int
64unmount_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
84	return (error);
85}
86
87static const struct statfs *
88find_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
100static void
101mount_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
143static void
144mount_if_not_already(const struct node *n, const char *map,
145    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, n->n_options, n->n_key);
179	free(from);
180	free(mountpoint);
181}
182
183static void
184mount_unmount(struct node *root)
185{
186	struct statfs *mntbuf;
187	struct node *n, *n2, *n3;
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, mntbuf, nitems);
220			continue;
221		}
222
223		TAILQ_FOREACH(n2, &n->n_children, n_next) {
224			TAILQ_FOREACH(n3, &n2->n_children, n_next) {
225				mount_if_not_already(n3, n->n_map,
226				    mntbuf, nitems);
227			}
228		}
229	}
230}
231
232static void
233flush_autofs(const char *fspath)
234{
235	struct iovec *iov = NULL;
236	char errmsg[255];
237	int error, iovlen = 0;
238
239	log_debugx("flushing %s", fspath);
240	memset(errmsg, 0, sizeof(errmsg));
241
242	build_iovec(&iov, &iovlen, "fstype",
243	    __DECONST(void *, "autofs"), (size_t)-1);
244	build_iovec(&iov, &iovlen, "fspath",
245	    __DECONST(void *, fspath), (size_t)-1);
246	build_iovec(&iov, &iovlen, "errmsg",
247	    errmsg, sizeof(errmsg));
248
249	error = nmount(iov, iovlen, MNT_UPDATE);
250	if (error != 0) {
251		if (*errmsg != '\0') {
252			log_err(1, "cannot flush %s: %s",
253			    fspath, errmsg);
254		} else {
255			log_err(1, "cannot flush %s", fspath);
256		}
257	}
258}
259
260static void
261flush_caches(void)
262{
263	struct statfs *mntbuf;
264	int i, nitems;
265
266	nitems = getmntinfo(&mntbuf, MNT_WAIT);
267	if (nitems <= 0)
268		log_err(1, "getmntinfo");
269
270	log_debugx("flushing autofs caches");
271
272	for (i = 0; i < nitems; i++) {
273		if (strcmp(mntbuf[i].f_fstypename, "autofs") != 0) {
274			log_debugx("skipping %s, filesystem type is not autofs",
275			    mntbuf[i].f_mntonname);
276			continue;
277		}
278
279		flush_autofs(mntbuf[i].f_mntonname);
280	}
281}
282
283static void
284unmount_automounted(bool force)
285{
286	struct statfs *mntbuf;
287	int i, nitems;
288
289	nitems = getmntinfo(&mntbuf, MNT_WAIT);
290	if (nitems <= 0)
291		log_err(1, "getmntinfo");
292
293	log_debugx("unmounting automounted filesystems");
294
295	for (i = 0; i < nitems; i++) {
296		if (strcmp(mntbuf[i].f_fstypename, "autofs") == 0) {
297			log_debugx("skipping %s, filesystem type is autofs",
298			    mntbuf[i].f_mntonname);
299			continue;
300		}
301
302		if ((mntbuf[i].f_flags & MNT_AUTOMOUNTED) == 0) {
303			log_debugx("skipping %s, not automounted",
304			    mntbuf[i].f_mntonname);
305			continue;
306		}
307
308		unmount_by_statfs(&(mntbuf[i]), force);
309	}
310}
311
312static void
313usage_automount(void)
314{
315
316	fprintf(stderr, "usage: automount [-D name=value][-o opts][-Lcfuv]\n");
317	exit(1);
318}
319
320int
321main_automount(int argc, char **argv)
322{
323	struct node *root;
324	int ch, debug = 0, show_maps = 0;
325	char *options = NULL;
326	bool do_unmount = false, force_unmount = false, flush = false;
327
328	/*
329	 * Note that in automount(8), the only purpose of variable
330	 * handling is to aid in debugging maps (automount -L).
331	 */
332	defined_init();
333
334	while ((ch = getopt(argc, argv, "D:Lfco:uv")) != -1) {
335		switch (ch) {
336		case 'D':
337			defined_parse_and_add(optarg);
338			break;
339		case 'L':
340			show_maps++;
341			break;
342		case 'c':
343			flush = true;
344			break;
345		case 'f':
346			force_unmount = true;
347			break;
348		case 'o':
349			if (options == NULL) {
350				options = checked_strdup(optarg);
351			} else {
352				options = concat(options, ',', optarg);
353			}
354			break;
355		case 'u':
356			do_unmount = true;
357			break;
358		case 'v':
359			debug++;
360			break;
361		case '?':
362		default:
363			usage_automount();
364		}
365	}
366	argc -= optind;
367	if (argc != 0)
368		usage_automount();
369
370	if (force_unmount && !do_unmount)
371		usage_automount();
372
373	log_init(debug);
374
375	if (flush) {
376		flush_caches();
377		return (0);
378	}
379
380	if (do_unmount) {
381		unmount_automounted(force_unmount);
382		return (0);
383	}
384
385	root = node_new_root();
386	parse_master(root, AUTO_MASTER_PATH);
387
388	if (show_maps) {
389		if (options != NULL) {
390			root->n_options = concat(options, ',', root->n_options);
391		}
392		if (show_maps > 1) {
393			node_expand_indirect_maps(root);
394			node_expand_ampersand(root, NULL);
395		}
396		node_expand_defined(root);
397		node_print(root);
398		return (0);
399	}
400
401	mount_unmount(root);
402
403	return (0);
404}
405