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
50 struct 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
58 static TAILQ_HEAD(, automounted_fs) automounted;
59
60 static struct automounted_fs *
automounted_find(fsid_t fsid)61 automounted_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
73 static struct automounted_fs *
automounted_add(fsid_t fsid,const char * mountpoint)74 automounted_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
90 static void
automounted_remove(struct automounted_fs * af)91 automounted_remove(struct automounted_fs *af)
92 {
93
94 TAILQ_REMOVE(&automounted, af, af_next);
95 free(af);
96 }
97
98 static void
refresh_automounted(void)99 refresh_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
151 static int
unmount_by_fsid(const fsid_t fsid,const char * mountpoint)152 unmount_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
178 static time_t
expire_automounted(time_t expiration_time)179 expire_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
219 static void
usage_autounmountd(void)220 usage_autounmountd(void)
221 {
222
223 fprintf(stderr, "usage: autounmountd [-r time][-t time][-dv]\n");
224 exit(1);
225 }
226
227 static void
do_wait(int kq,time_t sleep_time)228 do_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
260 int
main_autounmountd(int argc,char ** argv)261 main_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