usr.sbin/autofs/automount.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 <stdio.h>
  35 #include <stdlib.h>
  36 #include <string.h>
  37 #include <unistd.h>
  38 #include <vfs/autofs/autofs_mount.h>
  39
  40 #include "common.h"
  41
  42 static int
  43 unmount_by_statfs(const struct statfs *sb, bool force)
  44 {
  45         int error, flags;
  46
  47         log_debugx("unmounting %s", sb->f_mntonname);
  48
  49         flags = 0;
  50         if (force)
  51                 flags |= MNT_FORCE;
  52         error = unmount(sb->f_mntonname, flags);
  53         if (error != 0)
  54                 log_warn("cannot unmount %s", sb->f_mntonname);
  55
  56         return (error);
  57 }
  58
  59 static const struct statfs *
  60 find_statfs(const struct statfs *mntbuf, int nitems, const char *mountpoint)
  61 {
  62         int i;
  63
  64         for (i = 0; i < nitems; i++) {
  65                 if (strcmp(mntbuf[i].f_mntonname, mountpoint) == 0)
  66                         return (mntbuf + i);
  67         }
  68
  69         return (NULL);
  70 }
  71
  72 static void
  73 mount_autofs(const char *from, const char *fspath, const char *options,
  74     const char *prefix)
  75 {
  76         struct autofs_mount_info info;
  77         int error;
  78         char *cwd;
  79
  80         /*
  81          * There is no guarantee we are at /, so chdir to /.
  82          */
  83         cwd = getcwd(NULL, 0);
  84         if (chdir("/") != 0)
  85                 log_warn("failed to chdir to /");
  86         create_directory(fspath);
  87         if (chdir(cwd) != 0)
  88                 log_warn("failed to restore cwd");
  89         free(cwd);
  90
  91         log_debugx("mounting %s on %s, prefix \"%s\", options \"%s\"",
  92             from, fspath, prefix, options);
  93
  94         memset(&info, 0, sizeof(info));
  95         info.from = from;
  96         info.master_options = options;
  97         info.master_prefix = prefix;
  98
  99         error = mount("autofs", fspath, 0, &info);
 100         if (error != 0)
 101                 log_err(1, "cannot mount %s on %s", from, fspath);
 102 }
 103
 104 static void
 105 mount_if_not_already(const struct node *n, const char *map, const char *options,
 106     const char *prefix, const struct statfs *mntbuf, int nitems)
 107 {
 108         const struct statfs *sb;
 109         char *mountpoint;
 110         char *from;
 111         int ret;
 112
 113         ret = asprintf(&from, "map %s", map);
 114         if (ret < 0)
 115                 log_err(1, "asprintf");
 116
 117         mountpoint = node_path(n);
 118         sb = find_statfs(mntbuf, nitems, mountpoint);
 119         if (sb != NULL) {
 120                 if (strcmp(sb->f_fstypename, "autofs") != 0) {
 121                         log_debugx("unknown filesystem mounted "
 122                             "on %s; mounting", mountpoint);
 123                         /*
 124                          * XXX: Compare options and 'from',
 125                          *      and update the mount if necessary.
 126                          */
 127                 } else {
 128                         log_debugx("autofs already mounted "
 129                             "on %s", mountpoint);
 130                         free(from);
 131                         free(mountpoint);
 132                         return;
 133                 }
 134         } else {
 135                 log_debugx("nothing mounted on %s; mounting",
 136                     mountpoint);
 137         }
 138
 139         mount_autofs(from, mountpoint, options, prefix);
 140         free(from);
 141         free(mountpoint);
 142 }
 143
 144 static void
 145 mount_unmount(struct node *root)
 146 {
 147         struct statfs *mntbuf;
 148         struct node *n, *n2;
 149         int i, nitems;
 150
 151         nitems = getmntinfo(&mntbuf, MNT_WAIT);
 152         if (nitems <= 0)
 153                 log_err(1, "getmntinfo");
 154
 155         log_debugx("unmounting stale autofs mounts");
 156
 157         for (i = 0; i < nitems; i++) {
 158                 if (strcmp(mntbuf[i].f_fstypename, "autofs") != 0) {
 159                         log_debugx("skipping %s, filesystem type is not autofs",
 160                             mntbuf[i].f_mntonname);
 161                         continue;
 162                 }
 163
 164                 n = node_find(root, mntbuf[i].f_mntonname);
 165                 if (n != NULL) {
 166                         log_debugx("leaving autofs mounted on %s",
 167                             mntbuf[i].f_mntonname);
 168                         continue;
 169                 }
 170
 171                 log_debugx("autofs mounted on %s not found "
 172                     "in new configuration; unmounting", mntbuf[i].f_mntonname);
 173                 unmount_by_statfs(&(mntbuf[i]), false);
 174         }
 175
 176         log_debugx("mounting new autofs mounts");
 177
 178         TAILQ_FOREACH(n, &root->n_children, n_next) {
 179                 if (!node_is_direct_map(n)) {
 180                         mount_if_not_already(n, n->n_map, n->n_options,
 181                             n->n_key, mntbuf, nitems);
 182                         continue;
 183                 }
 184
 185                 TAILQ_FOREACH(n2, &n->n_children, n_next) {
 186                         mount_if_not_already(n2, n->n_map, n->n_options,
 187                             "/", mntbuf, nitems);
 188                 }
 189         }
 190 }
 191
 192 static void
 193 flush_autofs(const char *fspath)
 194 {
 195         int error;
 196
 197         log_debugx("flushing %s", fspath);
 198
 199         error = mount("autofs", fspath, MNT_UPDATE, NULL);
 200         if (error != 0)
 201                 log_err(1, "cannot flush %s", fspath);
 202 }
 203
 204 static void
 205 flush_caches(void)
 206 {
 207         struct statfs *mntbuf;
 208         int i, nitems;
 209
 210         nitems = getmntinfo(&mntbuf, MNT_WAIT);
 211         if (nitems <= 0)
 212                 log_err(1, "getmntinfo");
 213
 214         log_debugx("flushing autofs caches");
 215
 216         for (i = 0; i < nitems; i++) {
 217                 if (strcmp(mntbuf[i].f_fstypename, "autofs") != 0) {
 218                         log_debugx("skipping %s, filesystem type is not autofs",
 219                             mntbuf[i].f_mntonname);
 220                         continue;
 221                 }
 222
 223                 flush_autofs(mntbuf[i].f_mntonname);
 224         }
 225 }
 226
 227 static void
 228 unmount_automounted(bool force)
 229 {
 230         struct statfs *mntbuf;
 231         int i, nitems;
 232
 233         nitems = getmntinfo(&mntbuf, MNT_WAIT);
 234         if (nitems <= 0)
 235                 log_err(1, "getmntinfo");
 236
 237         log_debugx("unmounting automounted filesystems");
 238
 239         for (i = 0; i < nitems; i++) {
 240                 if (strcmp(mntbuf[i].f_fstypename, "autofs") == 0) {
 241                         log_debugx("skipping %s, filesystem type is autofs",
 242                             mntbuf[i].f_mntonname);
 243                         continue;
 244                 }
 245
 246                 if ((mntbuf[i].f_flags & MNT_AUTOMOUNTED) == 0) {
 247                         log_debugx("skipping %s, not automounted",
 248                             mntbuf[i].f_mntonname);
 249                         continue;
 250                 }
 251
 252                 unmount_by_statfs(&(mntbuf[i]), force);
 253         }
 254 }
 255
 256 static void
 257 usage_automount(void)
 258 {
 259
 260         fprintf(stderr, "usage: automount [-D name=value][-o opts][-Lcfuv]\n");
 261         exit(1);
 262 }
 263
 264 int
 265 main_automount(int argc, char **argv)
 266 {
 267         struct node *root;
 268         int ch, debug = 0, show_maps = 0;
 269         char *options = NULL;
 270         bool do_unmount = false, force_unmount = false, flush = false;
 271
 272         /*
 273          * Note that in automount(8), the only purpose of variable
 274          * handling is to aid in debugging maps (automount -L).
 275          */
 276         defined_init();
 277
 278         while ((ch = getopt(argc, argv, "D:Lfco:uv")) != -1) {
 279                 switch (ch) {
 280                 case 'D':
 281                         defined_parse_and_add(optarg);
 282                         break;
 283                 case 'L':
 284                         show_maps++;
 285                         break;
 286                 case 'c':
 287                         flush = true;
 288                         break;
 289                 case 'f':
 290                         force_unmount = true;
 291                         break;
 292                 case 'o':
 293                         options = concat(options, ',', optarg);
 294                         break;
 295                 case 'u':
 296                         do_unmount = true;
 297                         break;
 298                 case 'v':
 299                         debug++;
 300                         break;
 301                 case '?':
 302                 default:
 303                         usage_automount();
 304                 }
 305         }
 306         argc -= optind;
 307         if (argc != 0)
 308                 usage_automount();
 309
 310         if (force_unmount && !do_unmount)
 311                 usage_automount();
 312
 313         log_init(debug);
 314
 315         if (flush) {
 316                 flush_caches();
 317                 return (0);
 318         }
 319
 320         if (do_unmount) {
 321                 unmount_automounted(force_unmount);
 322                 return (0);
 323         }
 324
 325         root = node_new_root();
 326         parse_master(root, AUTO_MASTER_PATH);
 327
 328         if (show_maps) {
 329                 if (show_maps > 1) {
 330                         node_expand_indirect_maps(root);
 331                         node_expand_ampersand(root, NULL);
 332                 }
 333                 node_expand_defined(root);
 334                 node_print(root, options);
 335                 return (0);
 336         }
 337
 338         mount_unmount(root);
 339
 340         return (0);
 341 }