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
52 struct 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
60 static TAILQ_HEAD(, automounted_fs) automounted;
61
62 static struct automounted_fs *
automounted_find(fsid_t fsid)63 automounted_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
76 static struct automounted_fs *
automounted_add(fsid_t fsid,const char * mountpoint)77 automounted_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
93 static void
automounted_remove(struct automounted_fs * af)94 automounted_remove(struct automounted_fs *af)
95 {
96
97 TAILQ_REMOVE(&automounted, af, af_next);
98 free(af);
99 }
100
101 static void
refresh_automounted(void)102 refresh_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
154 static int
unmount_by_fsid(const fsid_t fsid,const char * mountpoint)155 unmount_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
180 static double
expire_automounted(double expiration_time)181 expire_automounted(double expiration_time)
182 {
183 struct automounted_fs *af, *tmpaf;
184 time_t now;
185 double mounted_for, mounted_max = -1.0;
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
221 static void
usage_autounmountd(void)222 usage_autounmountd(void)
223 {
224
225 fprintf(stderr, "usage: autounmountd [-r time][-t time][-dv]\n");
226 exit(1);
227 }
228
229 static void
do_wait(int kq,double sleep_time)230 do_wait(int kq, double sleep_time)
231 {
232 struct timespec timeout;
233 struct kevent unused;
234 int nevents;
235
236 if (sleep_time != -1.0) {
237 assert(sleep_time > 0.0);
238 timeout.tv_sec = sleep_time;
239 timeout.tv_nsec = 0;
240
241 log_debugx("waiting for filesystem event for %.0f seconds", sleep_time);
242 nevents = kevent(kq, NULL, 0, &unused, 1, &timeout);
243 } else {
244 log_debugx("waiting for filesystem event");
245 nevents = kevent(kq, NULL, 0, &unused, 1, NULL);
246 }
247 if (nevents < 0)
248 log_err(1, "kevent");
249
250 if (nevents == 0) {
251 log_debugx("timeout reached");
252 assert(sleep_time > 0.0);
253 } else {
254 log_debugx("got filesystem event");
255 }
256 }
257
258 int
main_autounmountd(int argc,char ** argv)259 main_autounmountd(int argc, char **argv)
260 {
261 struct kevent event;
262 struct pidfh *pidfh;
263 pid_t otherpid;
264 const char *pidfile_path = AUTOUNMOUNTD_PIDFILE;
265 int ch, debug = 0, error, kq;
266 double expiration_time = 600, retry_time = 600, mounted_max, sleep_time;
267 bool dont_daemonize = false;
268
269 while ((ch = getopt(argc, argv, "dr:t:v")) != -1) {
270 switch (ch) {
271 case 'd':
272 dont_daemonize = true;
273 debug++;
274 break;
275 case 'r':
276 retry_time = atoi(optarg);
277 break;
278 case 't':
279 expiration_time = atoi(optarg);
280 break;
281 case 'v':
282 debug++;
283 break;
284 case '?':
285 default:
286 usage_autounmountd();
287 }
288 }
289 argc -= optind;
290 if (argc != 0)
291 usage_autounmountd();
292
293 if (retry_time <= 0)
294 log_errx(1, "retry time must be greater than zero");
295 if (expiration_time <= 0)
296 log_errx(1, "expiration time must be greater than zero");
297
298 log_init(debug);
299
300 pidfh = pidfile_open(pidfile_path, 0600, &otherpid);
301 if (pidfh == NULL) {
302 if (errno == EEXIST) {
303 log_errx(1, "daemon already running, pid: %jd.",
304 (intmax_t)otherpid);
305 }
306 log_err(1, "cannot open or create pidfile \"%s\"",
307 pidfile_path);
308 }
309
310 if (dont_daemonize == false) {
311 if (daemon(0, 0) == -1) {
312 log_warn("cannot daemonize");
313 pidfile_remove(pidfh);
314 exit(1);
315 }
316 }
317
318 pidfile_write(pidfh);
319
320 TAILQ_INIT(&automounted);
321
322 kq = kqueue();
323 if (kq < 0)
324 log_err(1, "kqueue");
325
326 EV_SET(&event, 0, EVFILT_FS, EV_ADD | EV_CLEAR, 0, 0, NULL);
327 error = kevent(kq, &event, 1, NULL, 0, NULL);
328 if (error < 0)
329 log_err(1, "kevent");
330
331 for (;;) {
332 refresh_automounted();
333 mounted_max = expire_automounted(expiration_time);
334 if (mounted_max == -1.0) {
335 sleep_time = mounted_max;
336 log_debugx("no filesystems to expire");
337 } else if (mounted_max < expiration_time) {
338 sleep_time = difftime(expiration_time, mounted_max);
339 log_debugx("some filesystems expire in %.0f seconds",
340 sleep_time);
341 } else {
342 sleep_time = retry_time;
343 log_debugx("some expired filesystems remain mounted, "
344 "will retry in %.0f seconds", sleep_time);
345 }
346
347 do_wait(kq, sleep_time);
348 }
349
350 return (0);
351 }
352