usr.sbin/autofs/autounmountd.c

   1 /*-
   2  * Copyright (c) 2016 The DragonFly Project
   3  * Copyright (c) 2014 The FreeBSD Foundation
   4  * All rights reserved.
   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/mount.h>
  34 #include <sys/event.h>
  35 #include <sys/time.h>
  36 #include <assert.h>
  37 #include <errno.h>
  38 #include <stdio.h>
  39 #include <stdlib.h>
  40 #include <string.h>
  41 #include <unistd.h>
  42 #include <libutil.h>
  43
  44 #include "common.h"
  45
  46 #define AUTOUNMOUNTD_PIDFILE    "/var/run/autounmountd.pid"
  47
  48 struct automounted_fs {
  49         TAILQ_ENTRY(automounted_fs)     af_next;
  50         time_t                          af_mount_time;
  51         bool                            af_mark;
  52         fsid_t                          af_fsid;
  53         char                            af_mountpoint[MNAMELEN];
  54 };
  55
  56 static TAILQ_HEAD(, automounted_fs)     automounted;
  57
  58 static struct automounted_fs *
  59 automounted_find(fsid_t fsid)
  60 {
  61         struct automounted_fs *af;
  62
  63         TAILQ_FOREACH(af, &automounted, af_next) {
  64                 if (af->af_fsid.val[0] == fsid.val[0] &&
  65                     af->af_fsid.val[1] == fsid.val[1])
  66                         return (af);
  67         }
  68
  69         return (NULL);
  70 }
  71
  72 static struct automounted_fs *
  73 automounted_add(fsid_t fsid, const char *mountpoint)
  74 {
  75         struct automounted_fs *af;
  76
  77         af = calloc(sizeof(*af), 1);
  78         if (af == NULL)
  79                 log_err(1, "calloc");
  80         af->af_mount_time = time(NULL);
  81         af->af_fsid = fsid;
  82         strlcpy(af->af_mountpoint, mountpoint, sizeof(af->af_mountpoint));
  83
  84         TAILQ_INSERT_TAIL(&automounted, af, af_next);
  85
  86         return (af);
  87 }
  88
  89 static void
  90 automounted_remove(struct automounted_fs *af)
  91 {
  92
  93         TAILQ_REMOVE(&automounted, af, af_next);
  94         free(af);
  95 }
  96
  97 static void
  98 refresh_automounted(void)
  99 {
 100         struct automounted_fs *af, *tmpaf;
 101         struct statfs *mntbuf;
 102         int i, nitems;
 103
 104         nitems = getmntinfo(&mntbuf, MNT_WAIT);
 105         if (nitems <= 0)
 106                 log_err(1, "getmntinfo");
 107
 108         log_debugx("refreshing list of automounted filesystems");
 109
 110         TAILQ_FOREACH(af, &automounted, af_next)
 111                 af->af_mark = false;
 112
 113         for (i = 0; i < nitems; i++) {
 114                 if (strcmp(mntbuf[i].f_fstypename, "autofs") == 0) {
 115                         log_debugx("skipping %s, filesystem type is autofs",
 116                             mntbuf[i].f_mntonname);
 117                         continue;
 118                 }
 119
 120                 if ((mntbuf[i].f_flags & MNT_AUTOMOUNTED) == 0) {
 121                         log_debugx("skipping %s, not automounted",
 122                             mntbuf[i].f_mntonname);
 123                         continue;
 124                 }
 125
 126                 af = automounted_find(mntbuf[i].f_fsid);
 127                 if (af == NULL) {
 128                         log_debugx("new automounted filesystem found on %s "
 129                             "(FSID:%d:%d)", mntbuf[i].f_mntonname,
 130                             mntbuf[i].f_fsid.val[0], mntbuf[i].f_fsid.val[1]);
 131                         af = automounted_add(mntbuf[i].f_fsid,
 132                             mntbuf[i].f_mntonname);
 133                 } else {
 134                         log_debugx("already known automounted filesystem "
 135                             "found on %s (FSID:%d:%d)", mntbuf[i].f_mntonname,
 136                             mntbuf[i].f_fsid.val[0], mntbuf[i].f_fsid.val[1]);
 137                 }
 138                 af->af_mark = true;
 139         }
 140
 141         TAILQ_FOREACH_SAFE(af, &automounted, af_next, tmpaf) {
 142                 if (af->af_mark)
 143                         continue;
 144                 log_debugx("lost filesystem mounted on %s (FSID:%d:%d)",
 145                     af->af_mountpoint, af->af_fsid.val[0], af->af_fsid.val[1]);
 146                 automounted_remove(af);
 147         }
 148 }
 149
 150 static int
 151 do_unmount(const fsid_t fsid __unused, const char *mountpoint)
 152 {
 153         struct stat sb;
 154         int error, isbusy = 0;
 155
 156         error = unmount(mountpoint, 0);
 157         if (error != 0) {
 158                 if (errno == EBUSY) {
 159                         isbusy = 1;
 160                         log_debugx("cannot unmount %s: %s",
 161                             mountpoint, strerror(errno));
 162                 } else {
 163                         log_warn("cannot unmount %s", mountpoint);
 164                 }
 165         }
 166
 167         /*
 168          * XXX: Workaround for DragonFly kernel bug.
 169          * https://bugs.dragonflybsd.org/issues/2908
 170          */
 171         if (isbusy) {
 172                 log_debugx("workaround DragonFly kernel bug via stat(2)");
 173                 if (stat(mountpoint, &sb))
 174                         log_warn("cannot stat %s", mountpoint);
 175         }
 176
 177         return (error);
 178 }
 179
 180 static double
 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 = do_unmount(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
 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
 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
 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 }