1 /* $NetBSD: autounmountd.c,v 1.2 2019/11/21 16:45:05 tkusumi Exp $ */
2
3 /*-
4 * Copyright (c) 2017 The NetBSD Foundation, Inc.
5 * Copyright (c) 2016 The DragonFly Project
6 * Copyright (c) 2014 The FreeBSD Foundation
7 * All rights reserved.
8 *
9 * This code is derived from software contributed to The NetBSD Foundation
10 * by Tomohiro Kusumi <kusumi.tomohiro@gmail.com>.
11 *
12 * This software was developed by Edward Tomasz Napierala under sponsorship
13 * from the FreeBSD Foundation.
14 *
15 * Redistribution and use in source and binary forms, with or without
16 * modification, are permitted provided that the following conditions
17 * are met:
18 * 1. Redistributions of source code must retain the above copyright
19 * notice, this list of conditions and the following disclaimer.
20 * 2. Redistributions in binary form must reproduce the above copyright
21 * notice, this list of conditions and the following disclaimer in the
22 * documentation and/or other materials provided with the distribution.
23 *
24 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
25 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
26 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
27 * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
28 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
29 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
30 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
31 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
32 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
33 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
34 * SUCH DAMAGE.
35 *
36 */
37 #include <sys/cdefs.h>
38 __RCSID("$NetBSD: autounmountd.c,v 1.2 2019/11/21 16:45:05 tkusumi Exp $");
39
40 #include <sys/types.h>
41 #include <sys/mount.h>
42 #include <sys/event.h>
43 #include <sys/time.h>
44 #include <sys/fstypes.h>
45 #include <assert.h>
46 #include <errno.h>
47 #include <stdio.h>
48 #include <stdlib.h>
49 #include <string.h>
50 #include <unistd.h>
51 #include <util.h>
52
53 #include "common.h"
54
55 struct automounted_fs {
56 TAILQ_ENTRY(automounted_fs) af_next;
57 time_t af_mount_time;
58 bool af_mark;
59 fsid_t af_fsid;
60 char af_mountpoint[MNAMELEN];
61 };
62
63 static TAILQ_HEAD(, automounted_fs) automounted;
64
65 static struct automounted_fs *
automounted_find(fsid_t fsid)66 automounted_find(fsid_t fsid)
67 {
68 struct automounted_fs *af;
69
70 TAILQ_FOREACH(af, &automounted, af_next) {
71 if (af->af_fsid.__fsid_val[0] == fsid.__fsid_val[0] &&
72 af->af_fsid.__fsid_val[1] == fsid.__fsid_val[1])
73 return af;
74 }
75
76 return NULL;
77 }
78
79 static struct automounted_fs *
automounted_add(fsid_t fsid,const char * mountpoint)80 automounted_add(fsid_t fsid, const char *mountpoint)
81 {
82 struct automounted_fs *af;
83
84 af = calloc(1, sizeof(*af));
85 if (af == NULL)
86 log_err(1, "calloc");
87 af->af_mount_time = time(NULL);
88 af->af_fsid = fsid;
89 strlcpy(af->af_mountpoint, mountpoint, sizeof(af->af_mountpoint));
90
91 TAILQ_INSERT_TAIL(&automounted, af, af_next);
92
93 return af;
94 }
95
96 static void
automounted_remove(struct automounted_fs * af)97 automounted_remove(struct automounted_fs *af)
98 {
99
100 TAILQ_REMOVE(&automounted, af, af_next);
101 free(af);
102 }
103
104 static void
refresh_automounted(void)105 refresh_automounted(void)
106 {
107 struct automounted_fs *af, *tmpaf;
108 struct statvfs *mntbuf;
109 int i, nitems;
110
111 nitems = getmntinfo(&mntbuf, MNT_WAIT);
112 if (nitems <= 0)
113 log_err(1, "getmntinfo");
114
115 log_debugx("refreshing list of automounted filesystems");
116
117 TAILQ_FOREACH(af, &automounted, af_next)
118 af->af_mark = false;
119
120 for (i = 0; i < nitems; i++) {
121 if (strcmp(mntbuf[i].f_fstypename, "autofs") == 0) {
122 log_debugx("skipping %s, filesystem type is autofs",
123 mntbuf[i].f_mntonname);
124 continue;
125 }
126
127 if ((mntbuf[i].f_flag & MNT_AUTOMOUNTED) == 0) {
128 log_debugx("skipping %s, not automounted",
129 mntbuf[i].f_mntonname);
130 continue;
131 }
132
133 af = automounted_find(mntbuf[i].f_fsidx);
134 if (af == NULL) {
135 log_debugx("new automounted filesystem found on %s "
136 "(FSID:%d:%d)", mntbuf[i].f_mntonname,
137 mntbuf[i].f_fsidx.__fsid_val[0],
138 mntbuf[i].f_fsidx.__fsid_val[1]);
139 af = automounted_add(mntbuf[i].f_fsidx,
140 mntbuf[i].f_mntonname);
141 } else {
142 log_debugx("already known automounted filesystem "
143 "found on %s (FSID:%d:%d)", mntbuf[i].f_mntonname,
144 mntbuf[i].f_fsidx.__fsid_val[0],
145 mntbuf[i].f_fsidx.__fsid_val[1]);
146 }
147 af->af_mark = true;
148 }
149
150 TAILQ_FOREACH_SAFE(af, &automounted, af_next, tmpaf) {
151 if (af->af_mark)
152 continue;
153 log_debugx("lost filesystem mounted on %s (FSID:%d:%d)",
154 af->af_mountpoint, af->af_fsid.__fsid_val[0],
155 af->af_fsid.__fsid_val[1]);
156 automounted_remove(af);
157 }
158 }
159
160 static int
do_unmount(const fsid_t fsid __unused,const char * mountpoint)161 do_unmount(const fsid_t fsid __unused, const char *mountpoint)
162 {
163 int error;
164
165 error = unmount(mountpoint, 0);
166 if (error != 0) {
167 if (errno == EBUSY) {
168 log_debugx("cannot unmount %s: %s",
169 mountpoint, strerror(errno));
170 } else {
171 log_warn("cannot unmount %s", mountpoint);
172 }
173 }
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 = (time_t)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.__fsid_val[0],
197 af->af_fsid.__fsid_val[1],
198 (intmax_t)mounted_for);
199
200 if (mounted_for > mounted_max)
201 mounted_max = mounted_for;
202
203 continue;
204 }
205
206 log_debugx("filesystem mounted on %s (FSID:%d:%d), "
207 "was mounted for %jd seconds; unmounting",
208 af->af_mountpoint, af->af_fsid.__fsid_val[0],
209 af->af_fsid.__fsid_val[1], (intmax_t)mounted_for);
210 error = do_unmount(af->af_fsid, af->af_mountpoint);
211 if (error != 0) {
212 if (mounted_for > mounted_max)
213 mounted_max = mounted_for;
214 }
215 }
216
217 return mounted_max;
218 }
219
220 __dead static void
usage_autounmountd(void)221 usage_autounmountd(void)
222 {
223
224 fprintf(stderr, "Usage: %s [-r time][-t time][-dv]\n",
225 getprogname());
226 exit(1);
227 }
228
229 static void
do_wait(int kq,time_t sleep_time)230 do_wait(int kq, time_t sleep_time)
231 {
232 struct timespec timeout;
233 struct kevent unused;
234 int nevents;
235
236 if (sleep_time != -1) {
237 assert(sleep_time > 0);
238 timeout.tv_sec = (int)sleep_time;
239 timeout.tv_nsec = 0;
240
241 log_debugx("waiting for filesystem event for %jd seconds",
242 (intmax_t)sleep_time);
243 nevents = kevent(kq, NULL, 0, &unused, 1, &timeout);
244 } else {
245 log_debugx("waiting for filesystem event");
246 nevents = kevent(kq, NULL, 0, &unused, 1, NULL);
247 }
248 if (nevents < 0) {
249 if (errno == EINTR)
250 return;
251 log_err(1, "kevent");
252 }
253
254 if (nevents == 0) {
255 log_debugx("timeout reached");
256 assert(sleep_time > 0);
257 } else {
258 log_debugx("got filesystem event");
259 }
260 }
261
262 int
main_autounmountd(int argc,char ** argv)263 main_autounmountd(int argc, char **argv)
264 {
265 struct kevent event;
266 int ch, debug = 0, error, kq;
267 time_t expiration_time = 600, retry_time = 600, mounted_max, sleep_time;
268 bool dont_daemonize = false;
269
270 while ((ch = getopt(argc, argv, "dr:t:v")) != -1) {
271 switch (ch) {
272 case 'd':
273 dont_daemonize = true;
274 debug++;
275 break;
276 case 'r':
277 retry_time = atoi(optarg);
278 break;
279 case 't':
280 expiration_time = atoi(optarg);
281 break;
282 case 'v':
283 debug++;
284 break;
285 case '?':
286 default:
287 usage_autounmountd();
288 }
289 }
290 argc -= optind;
291 if (argc != 0)
292 usage_autounmountd();
293
294 if (retry_time <= 0)
295 log_errx(1, "retry time must be greater than zero");
296 if (expiration_time <= 0)
297 log_errx(1, "expiration time must be greater than zero");
298
299 log_init(debug);
300
301 if (dont_daemonize == false) {
302 if (daemon(0, 0) == -1) {
303 log_warn("cannot daemonize");
304 pidfile_clean();
305 exit(1);
306 }
307 }
308
309 /*
310 * Call pidfile(3) after daemon(3).
311 */
312 if (pidfile(NULL) == -1) {
313 if (errno == EEXIST)
314 log_errx(1, "daemon already running");
315 else if (errno == ENAMETOOLONG)
316 log_errx(1, "pidfile name too long");
317 log_err(1, "cannot create pidfile");
318 }
319 if (pidfile_lock(NULL) == -1)
320 log_err(1, "cannot lock pidfile");
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, 0, 0, (intptr_t)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 =
341 (time_t)difftime(expiration_time, mounted_max);
342 log_debugx("some filesystems expire in %jd seconds",
343 (intmax_t)sleep_time);
344 } else {
345 sleep_time = retry_time;
346 log_debugx("some expired filesystems remain mounted, "
347 "will retry in %jd seconds", (intmax_t)sleep_time);
348 }
349
350 do_wait(kq, sleep_time);
351 }
352
353 return 0;
354 }
355