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("$FreeBSD$");
33
34#include <sys/types.h>
35#include <sys/event.h>
36#include <sys/mount.h>
37#include <sys/time.h>
38#include <assert.h>
39#include <errno.h>
40#include <stdbool.h>
41#include <stdint.h>
42#include <stdio.h>
43#include <stdlib.h>
44#include <string.h>
45#include <unistd.h>
46#include <libutil.h>
47
48#include "common.h"
49
50#define AUTOUNMOUNTD_PIDFILE	"/var/run/autounmountd.pid"
51
52struct automounted_fs {
53	TAILQ_ENTRY(automounted_fs)	af_next;
54	time_t				af_mount_time;
55	bool				af_mark;
56	fsid_t				af_fsid;
57	char				af_mountpoint[MNAMELEN];
58};
59
60static TAILQ_HEAD(, automounted_fs)	automounted;
61
62static struct automounted_fs *
63automounted_find(fsid_t fsid)
64{
65	struct automounted_fs *af;
66
67	TAILQ_FOREACH(af, &automounted, af_next) {
68		if (af->af_fsid.val[0] == fsid.val[0] &&
69		    af->af_fsid.val[1] == fsid.val[1])
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(sizeof(*af), 1);
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_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	}
174
175	free(fsid_str);
176
177	return (error);
178}
179
180static double
181expire_automounted(double expiration_time)
182{
183	struct automounted_fs *af, *tmpaf;
184	time_t now;
185	double mounted_for, mounted_max = 0;
186	int error;
187
188	now = time(NULL);
189
190	log_debugx("expiring automounted filesystems");
191
192	TAILQ_FOREACH_SAFE(af, &automounted, af_next, tmpaf) {
193		mounted_for = difftime(now, af->af_mount_time);
194
195		if (mounted_for < expiration_time) {
196			log_debugx("skipping %s (FSID:%d:%d), mounted "
197			    "for %.0f seconds", af->af_mountpoint,
198			    af->af_fsid.val[0], af->af_fsid.val[1],
199			    mounted_for);
200
201			if (mounted_for > mounted_max)
202				mounted_max = mounted_for;
203
204			continue;
205		}
206
207		log_debugx("filesystem mounted on %s (FSID:%d:%d), "
208		    "was mounted for %.0f seconds; unmounting",
209		    af->af_mountpoint, af->af_fsid.val[0], af->af_fsid.val[1],
210		    mounted_for);
211		error = unmount_by_fsid(af->af_fsid, af->af_mountpoint);
212		if (error != 0) {
213			if (mounted_for > mounted_max)
214				mounted_max = mounted_for;
215		}
216	}
217
218	return (mounted_max);
219}
220
221static void
222usage_autounmountd(void)
223{
224
225	fprintf(stderr, "usage: autounmountd [-r time][-t time][-dv]\n");
226	exit(1);
227}
228
229static void
230do_wait(int kq, double sleep_time)
231{
232	struct timespec timeout;
233	struct kevent unused;
234	int error;
235
236	assert(sleep_time > 0);
237	timeout.tv_sec = sleep_time;
238	timeout.tv_nsec = 0;
239
240	log_debugx("waiting for filesystem event for %.0f seconds", sleep_time);
241	error = kevent(kq, NULL, 0, &unused, 1, &timeout);
242	if (error < 0)
243		log_err(1, "kevent");
244
245	if (error == 0)
246		log_debugx("timeout reached");
247	else
248		log_debugx("got filesystem event");
249}
250
251int
252main_autounmountd(int argc, char **argv)
253{
254	struct kevent event;
255	struct pidfh *pidfh;
256	pid_t otherpid;
257	const char *pidfile_path = AUTOUNMOUNTD_PIDFILE;
258	int ch, debug = 0, error, kq;
259	double expiration_time = 600, retry_time = 600, mounted_max, sleep_time;
260	bool dont_daemonize = false;
261
262	while ((ch = getopt(argc, argv, "dr:t:v")) != -1) {
263		switch (ch) {
264		case 'd':
265			dont_daemonize = true;
266			debug++;
267			break;
268		case 'r':
269			retry_time = atoi(optarg);
270			break;
271		case 't':
272			expiration_time = atoi(optarg);
273			break;
274		case 'v':
275			debug++;
276			break;
277		case '?':
278		default:
279			usage_autounmountd();
280		}
281	}
282	argc -= optind;
283	if (argc != 0)
284		usage_autounmountd();
285
286	if (retry_time <= 0)
287		log_errx(1, "retry time must be greater than zero");
288	if (expiration_time <= 0)
289		log_errx(1, "expiration time must be greater than zero");
290
291	log_init(debug);
292
293	pidfh = pidfile_open(pidfile_path, 0600, &otherpid);
294	if (pidfh == NULL) {
295		if (errno == EEXIST) {
296			log_errx(1, "daemon already running, pid: %jd.",
297			    (intmax_t)otherpid);
298		}
299		log_err(1, "cannot open or create pidfile \"%s\"",
300		    pidfile_path);
301	}
302
303	if (dont_daemonize == false) {
304		if (daemon(0, 0) == -1) {
305			log_warn("cannot daemonize");
306			pidfile_remove(pidfh);
307			exit(1);
308		}
309	}
310
311	pidfile_write(pidfh);
312
313	TAILQ_INIT(&automounted);
314
315	kq = kqueue();
316	if (kq < 0)
317		log_err(1, "kqueue");
318
319	EV_SET(&event, 0, EVFILT_FS, EV_ADD | EV_CLEAR, 0, 0, NULL);
320	error = kevent(kq, &event, 1, NULL, 0, NULL);
321	if (error < 0)
322		log_err(1, "kevent");
323
324	for (;;) {
325		refresh_automounted();
326		mounted_max = expire_automounted(expiration_time);
327		if (mounted_max < expiration_time) {
328			sleep_time = difftime(expiration_time, mounted_max);
329			log_debugx("some filesystems expire in %.0f seconds",
330			    sleep_time);
331		} else {
332			sleep_time = retry_time;
333			log_debugx("some expired filesystems remain mounted, "
334			    "will retry in %.0f seconds", sleep_time);
335		}
336
337		do_wait(kq, sleep_time);
338	}
339
340	return (0);
341}
342