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/event.h>
34#include <sys/mount.h>
35#include <sys/time.h>
36#include <assert.h>
37#include <errno.h>
38#include <libutil.h>
39#include <stdbool.h>
40#include <stdint.h>
41#include <stdio.h>
42#include <stdlib.h>
43#include <string.h>
44#include <unistd.h>
45
46#include "common.h"
47
48#define AUTOUNMOUNTD_PIDFILE	"/var/run/autounmountd.pid"
49
50struct automounted_fs {
51	TAILQ_ENTRY(automounted_fs)	af_next;
52	time_t				af_mount_time;
53	bool				af_mark;
54	fsid_t				af_fsid;
55	char				af_mountpoint[MNAMELEN];
56};
57
58static TAILQ_HEAD(, automounted_fs)	automounted;
59
60static struct automounted_fs *
61automounted_find(fsid_t fsid)
62{
63	struct automounted_fs *af;
64
65	TAILQ_FOREACH(af, &automounted, af_next) {
66		if (fsidcmp(&af->af_fsid, &fsid) == 0)
67			return (af);
68	}
69
70	return (NULL);
71}
72
73static struct automounted_fs *
74automounted_add(fsid_t fsid, const char *mountpoint)
75{
76	struct automounted_fs *af;
77
78	af = calloc(1, sizeof(*af));
79	if (af == NULL)
80		log_err(1, "calloc");
81	af->af_mount_time = time(NULL);
82	af->af_fsid = fsid;
83	strlcpy(af->af_mountpoint, mountpoint, sizeof(af->af_mountpoint));
84
85	TAILQ_INSERT_TAIL(&automounted, af, af_next);
86
87	return (af);
88}
89
90static void
91automounted_remove(struct automounted_fs *af)
92{
93
94	TAILQ_REMOVE(&automounted, af, af_next);
95	free(af);
96}
97
98static void
99refresh_automounted(void)
100{
101	struct automounted_fs *af, *tmpaf;
102	struct statfs *mntbuf;
103	int i, nitems;
104
105	nitems = getmntinfo(&mntbuf, MNT_WAIT);
106	if (nitems <= 0)
107		log_err(1, "getmntinfo");
108
109	log_debugx("refreshing list of automounted filesystems");
110
111	TAILQ_FOREACH(af, &automounted, af_next)
112		af->af_mark = false;
113
114	for (i = 0; i < nitems; i++) {
115		if (strcmp(mntbuf[i].f_fstypename, "autofs") == 0) {
116			log_debugx("skipping %s, filesystem type is autofs",
117			    mntbuf[i].f_mntonname);
118			continue;
119		}
120
121		if ((mntbuf[i].f_flags & MNT_AUTOMOUNTED) == 0) {
122			log_debugx("skipping %s, not automounted",
123			    mntbuf[i].f_mntonname);
124			continue;
125		}
126
127		af = automounted_find(mntbuf[i].f_fsid);
128		if (af == NULL) {
129			log_debugx("new automounted filesystem found on %s "
130			    "(FSID:%d:%d)", mntbuf[i].f_mntonname,
131			    mntbuf[i].f_fsid.val[0], mntbuf[i].f_fsid.val[1]);
132			af = automounted_add(mntbuf[i].f_fsid,
133			    mntbuf[i].f_mntonname);
134		} else {
135			log_debugx("already known automounted filesystem "
136			    "found on %s (FSID:%d:%d)", mntbuf[i].f_mntonname,
137			    mntbuf[i].f_fsid.val[0], mntbuf[i].f_fsid.val[1]);
138		}
139		af->af_mark = true;
140	}
141
142	TAILQ_FOREACH_SAFE(af, &automounted, af_next, tmpaf) {
143		if (af->af_mark)
144			continue;
145		log_debugx("lost filesystem mounted on %s (FSID:%d:%d)",
146		    af->af_mountpoint, af->af_fsid.val[0], af->af_fsid.val[1]);
147		automounted_remove(af);
148	}
149}
150
151static int
152unmount_by_fsid(const fsid_t fsid, const char *mountpoint)
153{
154	char *fsid_str;
155	int error, ret;
156
157	ret = asprintf(&fsid_str, "FSID:%d:%d", fsid.val[0], fsid.val[1]);
158	if (ret < 0)
159		log_err(1, "asprintf");
160
161	error = unmount(fsid_str, MNT_NONBUSY | MNT_BYFSID);
162	if (error != 0) {
163		if (errno == EBUSY) {
164			log_debugx("cannot unmount %s (%s): %s",
165			    mountpoint, fsid_str, strerror(errno));
166		} else {
167			log_warn("cannot unmount %s (%s)",
168			    mountpoint, fsid_str);
169		}
170	} else
171		rpc_umntall();
172
173	free(fsid_str);
174
175	return (error);
176}
177
178static time_t
179expire_automounted(time_t expiration_time)
180{
181	struct automounted_fs *af, *tmpaf;
182	time_t now;
183	time_t mounted_for, mounted_max = -1;
184	int error;
185
186	now = time(NULL);
187
188	log_debugx("expiring automounted filesystems");
189
190	TAILQ_FOREACH_SAFE(af, &automounted, af_next, tmpaf) {
191		mounted_for = difftime(now, af->af_mount_time);
192
193		if (mounted_for < expiration_time) {
194			log_debugx("skipping %s (FSID:%d:%d), mounted "
195			    "for %jd  seconds", af->af_mountpoint,
196			    af->af_fsid.val[0], af->af_fsid.val[1],
197			    (intmax_t)mounted_for);
198
199			if (mounted_for > mounted_max)
200				mounted_max = mounted_for;
201
202			continue;
203		}
204
205		log_debugx("filesystem mounted on %s (FSID:%d:%d), "
206		    "was mounted for %ld seconds; unmounting",
207		    af->af_mountpoint, af->af_fsid.val[0], af->af_fsid.val[1],
208		    (long)mounted_for);
209		error = unmount_by_fsid(af->af_fsid, af->af_mountpoint);
210		if (error != 0) {
211			if (mounted_for > mounted_max)
212				mounted_max = mounted_for;
213		}
214	}
215
216	return (mounted_max);
217}
218
219static void
220usage_autounmountd(void)
221{
222
223	fprintf(stderr, "usage: autounmountd [-r time][-t time][-dv]\n");
224	exit(1);
225}
226
227static void
228do_wait(int kq, time_t sleep_time)
229{
230	struct timespec timeout;
231	struct kevent unused;
232	int nevents;
233
234	if (sleep_time != -1) {
235		assert(sleep_time > 0);
236		timeout.tv_sec = sleep_time;
237		timeout.tv_nsec = 0;
238
239		log_debugx("waiting for filesystem event for %ld seconds",
240		    (long)sleep_time);
241		nevents = kevent(kq, NULL, 0, &unused, 1, &timeout);
242	} else {
243		log_debugx("waiting for filesystem event");
244		nevents = kevent(kq, NULL, 0, &unused, 1, NULL);
245	}
246	if (nevents < 0) {
247		if (errno == EINTR)
248			return;
249		log_err(1, "kevent");
250	}
251
252	if (nevents == 0) {
253		log_debugx("timeout reached");
254		assert(sleep_time > 0);
255	} else {
256		log_debugx("got filesystem event");
257	}
258}
259
260int
261main_autounmountd(int argc, char **argv)
262{
263	struct kevent event;
264	struct pidfh *pidfh;
265	pid_t otherpid;
266	const char *pidfile_path = AUTOUNMOUNTD_PIDFILE;
267	int ch, debug = 0, error, kq;
268	time_t expiration_time = 600, retry_time = 600, mounted_max, sleep_time;
269	bool dont_daemonize = false;
270
271	while ((ch = getopt(argc, argv, "dr:t:v")) != -1) {
272		switch (ch) {
273		case 'd':
274			dont_daemonize = true;
275			debug++;
276			break;
277		case 'r':
278			retry_time = atoi(optarg);
279			break;
280		case 't':
281			expiration_time = atoi(optarg);
282			break;
283		case 'v':
284			debug++;
285			break;
286		case '?':
287		default:
288			usage_autounmountd();
289		}
290	}
291	argc -= optind;
292	if (argc != 0)
293		usage_autounmountd();
294
295	if (retry_time <= 0)
296		log_errx(1, "retry time must be greater than zero");
297	if (expiration_time <= 0)
298		log_errx(1, "expiration time must be greater than zero");
299
300	log_init(debug);
301
302	pidfh = pidfile_open(pidfile_path, 0600, &otherpid);
303	if (pidfh == NULL) {
304		if (errno == EEXIST) {
305			log_errx(1, "daemon already running, pid: %jd.",
306			    (intmax_t)otherpid);
307		}
308		log_err(1, "cannot open or create pidfile \"%s\"",
309		    pidfile_path);
310	}
311
312	if (dont_daemonize == false) {
313		if (daemon(0, 0) == -1) {
314			log_warn("cannot daemonize");
315			pidfile_remove(pidfh);
316			exit(1);
317		}
318	}
319
320	pidfile_write(pidfh);
321
322	TAILQ_INIT(&automounted);
323
324	kq = kqueue();
325	if (kq < 0)
326		log_err(1, "kqueue");
327
328	EV_SET(&event, 0, EVFILT_FS, EV_ADD | EV_CLEAR, VQ_MOUNT | VQ_UNMOUNT, 0, NULL);
329	error = kevent(kq, &event, 1, NULL, 0, NULL);
330	if (error < 0)
331		log_err(1, "kevent");
332
333	for (;;) {
334		refresh_automounted();
335		mounted_max = expire_automounted(expiration_time);
336		if (mounted_max == -1) {
337			sleep_time = mounted_max;
338			log_debugx("no filesystems to expire");
339		} else if (mounted_max < expiration_time) {
340			sleep_time = difftime(expiration_time, mounted_max);
341			log_debugx("some filesystems expire in %ld  seconds",
342			    (long)sleep_time);
343		} else {
344			sleep_time = retry_time;
345			log_debugx("some expired filesystems remain mounted, "
346			    "will retry in %ld  seconds", (long)sleep_time);
347		}
348
349		do_wait(kq, sleep_time);
350	}
351
352	return (0);
353}
354