1/*-
2 * SPDX-License-Identifier: BSD-2-Clause-FreeBSD
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__FBSDID("$FreeBSD$");
34
35#include <sys/types.h>
36#include <sys/event.h>
37#include <sys/mount.h>
38#include <sys/time.h>
39#include <assert.h>
40#include <errno.h>
41#include <libutil.h>
42#include <stdbool.h>
43#include <stdint.h>
44#include <stdio.h>
45#include <stdlib.h>
46#include <string.h>
47#include <unistd.h>
48
49#include "common.h"
50
51#define AUTOUNMOUNTD_PIDFILE	"/var/run/autounmountd.pid"
52
53struct automounted_fs {
54	TAILQ_ENTRY(automounted_fs)	af_next;
55	time_t				af_mount_time;
56	bool				af_mark;
57	fsid_t				af_fsid;
58	char				af_mountpoint[MNAMELEN];
59};
60
61static TAILQ_HEAD(, automounted_fs)	automounted;
62
63static struct automounted_fs *
64automounted_find(fsid_t fsid)
65{
66	struct automounted_fs *af;
67
68	TAILQ_FOREACH(af, &automounted, af_next) {
69		if (fsidcmp(&af->af_fsid, &fsid) == 0)
70			return (af);
71	}
72
73	return (NULL);
74}
75
76static struct automounted_fs *
77automounted_add(fsid_t fsid, const char *mountpoint)
78{
79	struct automounted_fs *af;
80
81	af = calloc(1, sizeof(*af));
82	if (af == NULL)
83		log_err(1, "calloc");
84	af->af_mount_time = time(NULL);
85	af->af_fsid = fsid;
86	strlcpy(af->af_mountpoint, mountpoint, sizeof(af->af_mountpoint));
87
88	TAILQ_INSERT_TAIL(&automounted, af, af_next);
89
90	return (af);
91}
92
93static void
94automounted_remove(struct automounted_fs *af)
95{
96
97	TAILQ_REMOVE(&automounted, af, af_next);
98	free(af);
99}
100
101static void
102refresh_automounted(void)
103{
104	struct automounted_fs *af, *tmpaf;
105	struct statfs *mntbuf;
106	int i, nitems;
107
108	nitems = getmntinfo(&mntbuf, MNT_WAIT);
109	if (nitems <= 0)
110		log_err(1, "getmntinfo");
111
112	log_debugx("refreshing list of automounted filesystems");
113
114	TAILQ_FOREACH(af, &automounted, af_next)
115		af->af_mark = false;
116
117	for (i = 0; i < nitems; i++) {
118		if (strcmp(mntbuf[i].f_fstypename, "autofs") == 0) {
119			log_debugx("skipping %s, filesystem type is autofs",
120			    mntbuf[i].f_mntonname);
121			continue;
122		}
123
124		if ((mntbuf[i].f_flags & MNT_AUTOMOUNTED) == 0) {
125			log_debugx("skipping %s, not automounted",
126			    mntbuf[i].f_mntonname);
127			continue;
128		}
129
130		af = automounted_find(mntbuf[i].f_fsid);
131		if (af == NULL) {
132			log_debugx("new automounted filesystem found on %s "
133			    "(FSID:%d:%d)", mntbuf[i].f_mntonname,
134			    mntbuf[i].f_fsid.val[0], mntbuf[i].f_fsid.val[1]);
135			af = automounted_add(mntbuf[i].f_fsid,
136			    mntbuf[i].f_mntonname);
137		} else {
138			log_debugx("already known automounted filesystem "
139			    "found on %s (FSID:%d:%d)", mntbuf[i].f_mntonname,
140			    mntbuf[i].f_fsid.val[0], mntbuf[i].f_fsid.val[1]);
141		}
142		af->af_mark = true;
143	}
144
145	TAILQ_FOREACH_SAFE(af, &automounted, af_next, tmpaf) {
146		if (af->af_mark)
147			continue;
148		log_debugx("lost filesystem mounted on %s (FSID:%d:%d)",
149		    af->af_mountpoint, af->af_fsid.val[0], af->af_fsid.val[1]);
150		automounted_remove(af);
151	}
152}
153
154static int
155unmount_by_fsid(const fsid_t fsid, const char *mountpoint)
156{
157	char *fsid_str;
158	int error, ret;
159
160	ret = asprintf(&fsid_str, "FSID:%d:%d", fsid.val[0], fsid.val[1]);
161	if (ret < 0)
162		log_err(1, "asprintf");
163
164	error = unmount(fsid_str, MNT_NONBUSY | MNT_BYFSID);
165	if (error != 0) {
166		if (errno == EBUSY) {
167			log_debugx("cannot unmount %s (%s): %s",
168			    mountpoint, fsid_str, strerror(errno));
169		} else {
170			log_warn("cannot unmount %s (%s)",
171			    mountpoint, fsid_str);
172		}
173	} else
174		rpc_umntall();
175
176	free(fsid_str);
177
178	return (error);
179}
180
181static time_t
182expire_automounted(time_t expiration_time)
183{
184	struct automounted_fs *af, *tmpaf;
185	time_t now;
186	time_t mounted_for, mounted_max = -1;
187	int error;
188
189	now = time(NULL);
190
191	log_debugx("expiring automounted filesystems");
192
193	TAILQ_FOREACH_SAFE(af, &automounted, af_next, tmpaf) {
194		mounted_for = difftime(now, af->af_mount_time);
195
196		if (mounted_for < expiration_time) {
197			log_debugx("skipping %s (FSID:%d:%d), mounted "
198			    "for %jd  seconds", af->af_mountpoint,
199			    af->af_fsid.val[0], af->af_fsid.val[1],
200			    (intmax_t)mounted_for);
201
202			if (mounted_for > mounted_max)
203				mounted_max = mounted_for;
204
205			continue;
206		}
207
208		log_debugx("filesystem mounted on %s (FSID:%d:%d), "
209		    "was mounted for %ld seconds; unmounting",
210		    af->af_mountpoint, af->af_fsid.val[0], af->af_fsid.val[1],
211		    (long)mounted_for);
212		error = unmount_by_fsid(af->af_fsid, af->af_mountpoint);
213		if (error != 0) {
214			if (mounted_for > mounted_max)
215				mounted_max = mounted_for;
216		}
217	}
218
219	return (mounted_max);
220}
221
222static void
223usage_autounmountd(void)
224{
225
226	fprintf(stderr, "usage: autounmountd [-r time][-t time][-dv]\n");
227	exit(1);
228}
229
230static void
231do_wait(int kq, time_t sleep_time)
232{
233	struct timespec timeout;
234	struct kevent unused;
235	int nevents;
236
237	if (sleep_time != -1) {
238		assert(sleep_time > 0);
239		timeout.tv_sec = sleep_time;
240		timeout.tv_nsec = 0;
241
242		log_debugx("waiting for filesystem event for %ld seconds",
243		    (long)sleep_time);
244		nevents = kevent(kq, NULL, 0, &unused, 1, &timeout);
245	} else {
246		log_debugx("waiting for filesystem event");
247		nevents = kevent(kq, NULL, 0, &unused, 1, NULL);
248	}
249	if (nevents < 0) {
250		if (errno == EINTR)
251			return;
252		log_err(1, "kevent");
253	}
254
255	if (nevents == 0) {
256		log_debugx("timeout reached");
257		assert(sleep_time > 0);
258	} else {
259		log_debugx("got filesystem event");
260	}
261}
262
263int
264main_autounmountd(int argc, char **argv)
265{
266	struct kevent event;
267	struct pidfh *pidfh;
268	pid_t otherpid;
269	const char *pidfile_path = AUTOUNMOUNTD_PIDFILE;
270	int ch, debug = 0, error, kq;
271	time_t expiration_time = 600, retry_time = 600, mounted_max, sleep_time;
272	bool dont_daemonize = false;
273
274	while ((ch = getopt(argc, argv, "dr:t:v")) != -1) {
275		switch (ch) {
276		case 'd':
277			dont_daemonize = true;
278			debug++;
279			break;
280		case 'r':
281			retry_time = atoi(optarg);
282			break;
283		case 't':
284			expiration_time = atoi(optarg);
285			break;
286		case 'v':
287			debug++;
288			break;
289		case '?':
290		default:
291			usage_autounmountd();
292		}
293	}
294	argc -= optind;
295	if (argc != 0)
296		usage_autounmountd();
297
298	if (retry_time <= 0)
299		log_errx(1, "retry time must be greater than zero");
300	if (expiration_time <= 0)
301		log_errx(1, "expiration time must be greater than zero");
302
303	log_init(debug);
304
305	pidfh = pidfile_open(pidfile_path, 0600, &otherpid);
306	if (pidfh == NULL) {
307		if (errno == EEXIST) {
308			log_errx(1, "daemon already running, pid: %jd.",
309			    (intmax_t)otherpid);
310		}
311		log_err(1, "cannot open or create pidfile \"%s\"",
312		    pidfile_path);
313	}
314
315	if (dont_daemonize == false) {
316		if (daemon(0, 0) == -1) {
317			log_warn("cannot daemonize");
318			pidfile_remove(pidfh);
319			exit(1);
320		}
321	}
322
323	pidfile_write(pidfh);
324
325	TAILQ_INIT(&automounted);
326
327	kq = kqueue();
328	if (kq < 0)
329		log_err(1, "kqueue");
330
331	EV_SET(&event, 0, EVFILT_FS, EV_ADD | EV_CLEAR, 0, 0, NULL);
332	error = kevent(kq, &event, 1, NULL, 0, NULL);
333	if (error < 0)
334		log_err(1, "kevent");
335
336	for (;;) {
337		refresh_automounted();
338		mounted_max = expire_automounted(expiration_time);
339		if (mounted_max == -1) {
340			sleep_time = mounted_max;
341			log_debugx("no filesystems to expire");
342		} else if (mounted_max < expiration_time) {
343			sleep_time = difftime(expiration_time, mounted_max);
344			log_debugx("some filesystems expire in %ld  seconds",
345			    (long)sleep_time);
346		} else {
347			sleep_time = retry_time;
348			log_debugx("some expired filesystems remain mounted, "
349			    "will retry in %ld  seconds", (long)sleep_time);
350		}
351
352		do_wait(kq, sleep_time);
353	}
354
355	return (0);
356}
357