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/types.h>
33#include <sys/time.h>
34#include <sys/ioctl.h>
35#include <sys/param.h>
36#include <sys/linker.h>
37#include <sys/mount.h>
38#include <sys/socket.h>
39#include <sys/stat.h>
40#include <sys/wait.h>
41#include <sys/utsname.h>
42#include <assert.h>
43#include <ctype.h>
44#include <errno.h>
45#include <fcntl.h>
46#include <libgen.h>
47#include <libutil.h>
48#include <netdb.h>
49#include <signal.h>
50#include <stdbool.h>
51#include <stdint.h>
52#include <stdio.h>
53#include <stdlib.h>
54#include <string.h>
55#include <unistd.h>
56
57#include "common.h"
58#include "mntopts.h"
59
60static int
61unmount_by_statfs(const struct statfs *sb, bool force)
62{
63	char *fsid_str;
64	int error, ret, flags;
65
66	ret = asprintf(&fsid_str, "FSID:%d:%d",
67	    sb->f_fsid.val[0], sb->f_fsid.val[1]);
68	if (ret < 0)
69		log_err(1, "asprintf");
70
71	log_debugx("unmounting %s using %s", sb->f_mntonname, fsid_str);
72
73	flags = MNT_BYFSID;
74	if (force)
75		flags |= MNT_FORCE;
76	error = unmount(fsid_str, flags);
77	free(fsid_str);
78	if (error != 0)
79		log_warn("cannot unmount %s", sb->f_mntonname);
80	else
81		rpc_umntall();
82
83	return (error);
84}
85
86static const struct statfs *
87find_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
99static void
100mount_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
142static void
143mount_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
182static void
183mount_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
230static void
231flush_autofs(const char *fspath, const fsid_t *fsid)
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, "fsid",
245	    __DECONST(void *, fsid), sizeof(*fsid));
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	struct statfs statbuf;
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		 * A direct map mountpoint may have been mounted over, in
281		 * which case we can't MNT_UPDATE it. There's an obvious race
282		 * condition remaining here, but that has to be fixed in the
283		 * kernel.
284		 */
285		if (statfs(mntbuf[i].f_mntonname, &statbuf) != 0) {
286			log_err(1, "cannot statfs %s", mntbuf[i].f_mntonname);
287			continue;
288		}
289		if (strcmp(statbuf.f_fstypename, "autofs") != 0) {
290			log_debugx("skipping %s, filesystem type is not autofs",
291			    mntbuf[i].f_mntonname);
292			continue;
293		}
294
295		flush_autofs(mntbuf[i].f_mntonname, &statbuf.f_fsid);
296	}
297}
298
299static void
300unmount_automounted(bool force)
301{
302	struct statfs *mntbuf;
303	int i, nitems;
304
305	nitems = getmntinfo(&mntbuf, MNT_WAIT);
306	if (nitems <= 0)
307		log_err(1, "getmntinfo");
308
309	log_debugx("unmounting automounted filesystems");
310
311	for (i = 0; i < nitems; i++) {
312		if (strcmp(mntbuf[i].f_fstypename, "autofs") == 0) {
313			log_debugx("skipping %s, filesystem type is autofs",
314			    mntbuf[i].f_mntonname);
315			continue;
316		}
317
318		if ((mntbuf[i].f_flags & MNT_AUTOMOUNTED) == 0) {
319			log_debugx("skipping %s, not automounted",
320			    mntbuf[i].f_mntonname);
321			continue;
322		}
323
324		unmount_by_statfs(&(mntbuf[i]), force);
325	}
326}
327
328static void
329usage_automount(void)
330{
331
332	fprintf(stderr, "usage: automount [-D name=value][-o opts][-Lcfuv]\n");
333	exit(1);
334}
335
336int
337main_automount(int argc, char **argv)
338{
339	struct node *root;
340	int ch, debug = 0, show_maps = 0;
341	char *options = NULL;
342	bool do_unmount = false, force_unmount = false, flush = false;
343
344	/*
345	 * Note that in automount(8), the only purpose of variable
346	 * handling is to aid in debugging maps (automount -L).
347	 */
348	defined_init();
349
350	while ((ch = getopt(argc, argv, "D:Lfco:uv")) != -1) {
351		switch (ch) {
352		case 'D':
353			defined_parse_and_add(optarg);
354			break;
355		case 'L':
356			show_maps++;
357			break;
358		case 'c':
359			flush = true;
360			break;
361		case 'f':
362			force_unmount = true;
363			break;
364		case 'o':
365			options = concat(options, ',', optarg);
366			break;
367		case 'u':
368			do_unmount = true;
369			break;
370		case 'v':
371			debug++;
372			break;
373		case '?':
374		default:
375			usage_automount();
376		}
377	}
378	argc -= optind;
379	if (argc != 0)
380		usage_automount();
381
382	if (force_unmount && !do_unmount)
383		usage_automount();
384
385	log_init(debug);
386
387	if (flush) {
388		flush_caches();
389		return (0);
390	}
391
392	if (do_unmount) {
393		unmount_automounted(force_unmount);
394		return (0);
395	}
396
397	root = node_new_root();
398	parse_master(root, AUTO_MASTER_PATH);
399
400	if (show_maps) {
401		if (show_maps > 1) {
402			node_expand_indirect_maps(root);
403			node_expand_ampersand(root, NULL);
404		}
405		node_expand_defined(root);
406		node_print(root, options);
407		return (0);
408	}
409
410	mount_unmount(root);
411
412	return (0);
413}
414