1/*-
2 * SPDX-License-Identifier: BSD-2-Clause-FreeBSD
3 *
4 * Copyright (c) 2014 The FreeBSD Foundation
5 * All rights reserved.
6 *
7 * This software was developed by Edward Tomasz Napierala under sponsorship
8 * from the FreeBSD Foundation.
9 *
10 * Redistribution and use in source and binary forms, with or without
11 * modification, are permitted provided that the following conditions
12 * are met:
13 * 1. Redistributions of source code must retain the above copyright
14 *    notice, this list of conditions and the following disclaimer.
15 * 2. Redistributions in binary form must reproduce the above copyright
16 *    notice, this list of conditions and the following disclaimer in the
17 *    documentation and/or other materials provided with the distribution.
18 *
19 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
20 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
21 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
22 * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
23 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
24 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
25 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
26 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
27 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
28 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
29 * SUCH DAMAGE.
30 *
31 */
32
33#include <sys/cdefs.h>
34__FBSDID("$FreeBSD: stable/11/usr.sbin/autofs/automount.c 332597 2018-04-16 16:16:24Z trasz $");
35
36#include <sys/types.h>
37#include <sys/time.h>
38#include <sys/ioctl.h>
39#include <sys/param.h>
40#include <sys/linker.h>
41#include <sys/mount.h>
42#include <sys/socket.h>
43#include <sys/stat.h>
44#include <sys/wait.h>
45#include <sys/utsname.h>
46#include <assert.h>
47#include <ctype.h>
48#include <errno.h>
49#include <fcntl.h>
50#include <libgen.h>
51#include <libutil.h>
52#include <netdb.h>
53#include <signal.h>
54#include <stdbool.h>
55#include <stdint.h>
56#include <stdio.h>
57#include <stdlib.h>
58#include <string.h>
59#include <unistd.h>
60
61#include "common.h"
62#include "mntopts.h"
63
64static int
65unmount_by_statfs(const struct statfs *sb, bool force)
66{
67	char *fsid_str;
68	int error, ret, flags;
69
70	ret = asprintf(&fsid_str, "FSID:%d:%d",
71	    sb->f_fsid.val[0], sb->f_fsid.val[1]);
72	if (ret < 0)
73		log_err(1, "asprintf");
74
75	log_debugx("unmounting %s using %s", sb->f_mntonname, fsid_str);
76
77	flags = MNT_BYFSID;
78	if (force)
79		flags |= MNT_FORCE;
80	error = unmount(fsid_str, flags);
81	free(fsid_str);
82	if (error != 0)
83		log_warn("cannot unmount %s", sb->f_mntonname);
84
85	return (error);
86}
87
88static const struct statfs *
89find_statfs(const struct statfs *mntbuf, int nitems, const char *mountpoint)
90{
91	int i;
92
93	for (i = 0; i < nitems; i++) {
94		if (strcmp(mntbuf[i].f_mntonname, mountpoint) == 0)
95			return (mntbuf + i);
96	}
97
98	return (NULL);
99}
100
101static void
102mount_autofs(const char *from, const char *fspath, const char *options,
103    const char *prefix)
104{
105	struct iovec *iov = NULL;
106	char errmsg[255];
107	int error, iovlen = 0;
108
109	create_directory(fspath);
110
111	log_debugx("mounting %s on %s, prefix \"%s\", options \"%s\"",
112	    from, fspath, prefix, options);
113	memset(errmsg, 0, sizeof(errmsg));
114
115	build_iovec(&iov, &iovlen, "fstype",
116	    __DECONST(void *, "autofs"), (size_t)-1);
117	build_iovec(&iov, &iovlen, "fspath",
118	    __DECONST(void *, fspath), (size_t)-1);
119	build_iovec(&iov, &iovlen, "from",
120	    __DECONST(void *, from), (size_t)-1);
121	build_iovec(&iov, &iovlen, "errmsg",
122	    errmsg, sizeof(errmsg));
123
124	/*
125	 * Append the options and mountpoint defined in auto_master(5);
126	 * this way automountd(8) does not need to parse it.
127	 */
128	build_iovec(&iov, &iovlen, "master_options",
129	    __DECONST(void *, options), (size_t)-1);
130	build_iovec(&iov, &iovlen, "master_prefix",
131	    __DECONST(void *, prefix), (size_t)-1);
132
133	error = nmount(iov, iovlen, 0);
134	if (error != 0) {
135		if (*errmsg != '\0') {
136			log_err(1, "cannot mount %s on %s: %s",
137			    from, fspath, errmsg);
138		} else {
139			log_err(1, "cannot mount %s on %s", from, fspath);
140		}
141	}
142}
143
144static void
145mount_if_not_already(const struct node *n, const char *map, const char *options,
146    const char *prefix, const struct statfs *mntbuf, int nitems)
147{
148	const struct statfs *sb;
149	char *mountpoint;
150	char *from;
151	int ret;
152
153	ret = asprintf(&from, "map %s", map);
154	if (ret < 0)
155		log_err(1, "asprintf");
156
157	mountpoint = node_path(n);
158	sb = find_statfs(mntbuf, nitems, mountpoint);
159	if (sb != NULL) {
160		if (strcmp(sb->f_fstypename, "autofs") != 0) {
161			log_debugx("unknown filesystem mounted "
162			    "on %s; mounting", mountpoint);
163			/*
164			 * XXX: Compare options and 'from',
165			 *	and update the mount if necessary.
166			 */
167		} else {
168			log_debugx("autofs already mounted "
169			    "on %s", mountpoint);
170			free(from);
171			free(mountpoint);
172			return;
173		}
174	} else {
175		log_debugx("nothing mounted on %s; mounting",
176		    mountpoint);
177	}
178
179	mount_autofs(from, mountpoint, options, prefix);
180	free(from);
181	free(mountpoint);
182}
183
184static void
185mount_unmount(struct node *root)
186{
187	struct statfs *mntbuf;
188	struct node *n, *n2;
189	int i, nitems;
190
191	nitems = getmntinfo(&mntbuf, MNT_WAIT);
192	if (nitems <= 0)
193		log_err(1, "getmntinfo");
194
195	log_debugx("unmounting stale autofs mounts");
196
197	for (i = 0; i < nitems; i++) {
198		if (strcmp(mntbuf[i].f_fstypename, "autofs") != 0) {
199			log_debugx("skipping %s, filesystem type is not autofs",
200			    mntbuf[i].f_mntonname);
201			continue;
202		}
203
204		n = node_find(root, mntbuf[i].f_mntonname);
205		if (n != NULL) {
206			log_debugx("leaving autofs mounted on %s",
207			    mntbuf[i].f_mntonname);
208			continue;
209		}
210
211		log_debugx("autofs mounted on %s not found "
212		    "in new configuration; unmounting", mntbuf[i].f_mntonname);
213		unmount_by_statfs(&(mntbuf[i]), false);
214	}
215
216	log_debugx("mounting new autofs mounts");
217
218	TAILQ_FOREACH(n, &root->n_children, n_next) {
219		if (!node_is_direct_map(n)) {
220			mount_if_not_already(n, n->n_map, n->n_options,
221			    n->n_key, mntbuf, nitems);
222			continue;
223		}
224
225		TAILQ_FOREACH(n2, &n->n_children, n_next) {
226			mount_if_not_already(n2, n->n_map, n->n_options,
227			    "/", mntbuf, nitems);
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			options = concat(options, ',', optarg);
350			break;
351		case 'u':
352			do_unmount = true;
353			break;
354		case 'v':
355			debug++;
356			break;
357		case '?':
358		default:
359			usage_automount();
360		}
361	}
362	argc -= optind;
363	if (argc != 0)
364		usage_automount();
365
366	if (force_unmount && !do_unmount)
367		usage_automount();
368
369	log_init(debug);
370
371	if (flush) {
372		flush_caches();
373		return (0);
374	}
375
376	if (do_unmount) {
377		unmount_automounted(force_unmount);
378		return (0);
379	}
380
381	root = node_new_root();
382	parse_master(root, AUTO_MASTER_PATH);
383
384	if (show_maps) {
385		if (show_maps > 1) {
386			node_expand_indirect_maps(root);
387			node_expand_ampersand(root, NULL);
388		}
389		node_expand_defined(root);
390		node_print(root, options);
391		return (0);
392	}
393
394	mount_unmount(root);
395
396	return (0);
397}
398