src/fstab-generator/fstab-generator.c

   1 /*-*- Mode: C; c-basic-offset: 8; indent-tabs-mode: nil -*-*/
   2
   3 /***
   4   This file is part of systemd.
   5
   6   Copyright 2012 Lennart Poettering
   7
   8   systemd is free software; you can redistribute it and/or modify it
   9   under the terms of the GNU Lesser General Public License as published by
  10   the Free Software Foundation; either version 2.1 of the License, or
  11   (at your option) any later version.
  12
  13   systemd is distributed in the hope that it will be useful, but
  14   WITHOUT ANY WARRANTY; without even the implied warranty of
  15   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
  16   Lesser General Public License for more details.
  17
  18   You should have received a copy of the GNU Lesser General Public License
  19   along with systemd; If not, see <http://www.gnu.org/licenses/>.
  20 ***/
  21
  22 #include <stdio.h>
  23 #include <mntent.h>
  24 #include <errno.h>
  25 #include <string.h>
  26 #include <unistd.h>
  27
  28 #include "log.h"
  29 #include "util.h"
  30 #include "unit-name.h"
  31 #include "path-util.h"
  32 #include "mount-setup.h"
  33 #include "special.h"
  34 #include "mkdir.h"
  35 #include "virt.h"
  36 #include "fileio.h"
  37
  38 static const char *arg_dest = "/tmp";
  39 static bool arg_enabled = true;
  40
  41 static int device_name(const char *path, char **unit) {
  42         char *p;
  43
  44         assert(path);
  45
  46         if (!is_device_path(path))
  47                 return 0;
  48
  49         p = unit_name_from_path(path, ".device");
  50         if (!p)
  51                 return log_oom();
  52
  53         *unit = p;
  54         return 1;
  55 }
  56
  57 static int mount_find_pri(struct mntent *me, int *ret) {
  58         char *end, *pri;
  59         unsigned long r;
  60
  61         assert(me);
  62         assert(ret);
  63
  64         pri = hasmntopt(me, "pri");
  65         if (!pri)
  66                 return 0;
  67
  68         pri += 4;
  69
  70         errno = 0;
  71         r = strtoul(pri, &end, 10);
  72         if (errno != 0)
  73                 return -errno;
  74
  75         if (end == pri || (*end != ',' && *end != 0))
  76                 return -EINVAL;
  77
  78         *ret = (int) r;
  79         return 1;
  80 }
  81
  82 static int add_swap(const char *what, struct mntent *me) {
  83         char _cleanup_free_ *name = NULL, *unit = NULL, *lnk = NULL, *device = NULL;
  84         FILE _cleanup_fclose_ *f = NULL;
  85         bool noauto, nofail;
  86         int r, pri = -1;
  87
  88         assert(what);
  89         assert(me);
  90
  91         r = mount_find_pri(me, &pri);
  92         if (r < 0) {
  93                 log_error("Failed to parse priority");
  94                 return pri;
  95         }
  96
  97         noauto = !!hasmntopt(me, "noauto");
  98         nofail = !!hasmntopt(me, "nofail");
  99
 100         name = unit_name_from_path(what, ".swap");
 101         if (!name)
 102                 return log_oom();
 103
 104         unit = strjoin(arg_dest, "/", name, NULL);
 105         if (!unit)
 106                 return log_oom();
 107
 108         f = fopen(unit, "wxe");
 109         if (!f) {
 110                 if (errno == EEXIST)
 111                         log_error("Failed to create swap unit file %s, as it already exists. Duplicate entry in /etc/fstab?", unit);
 112                 else
 113                         log_error("Failed to create unit file %s: %m", unit);
 114                 return -errno;
 115         }
 116
 117         fputs("# Automatically generated by systemd-fstab-generator\n\n"
 118               "[Unit]\n"
 119               "SourcePath=/etc/fstab\n"
 120               "DefaultDependencies=no\n"
 121               "Conflicts=" SPECIAL_UMOUNT_TARGET "\n"
 122               "Before=" SPECIAL_UMOUNT_TARGET "\n", f);
 123
 124         if (!noauto && !nofail)
 125                 fputs("Before=" SPECIAL_SWAP_TARGET "\n", f);
 126
 127         fprintf(f,
 128                 "\n"
 129                 "[Swap]\n"
 130                 "What=%s\n",
 131                 what);
 132
 133         if (pri >= 0)
 134                 fprintf(f,
 135                         "Priority=%i\n",
 136                         pri);
 137
 138         fflush(f);
 139         if (ferror(f)) {
 140                 log_error("Failed to write unit file %s: %m", unit);
 141                 return -errno;
 142         }
 143
 144         if (!noauto) {
 145                 lnk = strjoin(arg_dest, "/" SPECIAL_SWAP_TARGET ".wants/", name, NULL);
 146                 if (!lnk)
 147                         return log_oom();
 148
 149                 mkdir_parents_label(lnk, 0755);
 150                 if (symlink(unit, lnk) < 0) {
 151                         log_error("Failed to create symlink %s: %m", lnk);
 152                         return -errno;
 153                 }
 154
 155                 r = device_name(what, &device);
 156                 if (r < 0)
 157                         return r;
 158
 159                 if (r > 0) {
 160                         free(lnk);
 161                         lnk = strjoin(arg_dest, "/", device, ".wants/", name, NULL);
 162                         if (!lnk)
 163                                 return log_oom();
 164
 165                         mkdir_parents_label(lnk, 0755);
 166                         if (symlink(unit, lnk) < 0) {
 167                                 log_error("Failed to create symlink %s: %m", lnk);
 168                                 return -errno;
 169                         }
 170                 }
 171         }
 172
 173         return 0;
 174 }
 175
 176 static bool mount_is_bind(struct mntent *me) {
 177         assert(me);
 178
 179         return
 180                 hasmntopt(me, "bind") ||
 181                 streq(me->mnt_type, "bind") ||
 182                 hasmntopt(me, "rbind") ||
 183                 streq(me->mnt_type, "rbind");
 184 }
 185
 186 static bool mount_is_network(struct mntent *me) {
 187         assert(me);
 188
 189         return
 190                 hasmntopt(me, "_netdev") ||
 191                 fstype_is_network(me->mnt_type);
 192 }
 193
 194 static bool mount_in_initrd(struct mntent *me) {
 195         assert(me);
 196
 197         return
 198                 hasmntopt(me, "x-initrd.mount") ||
 199                 streq(me->mnt_dir, "/usr");
 200 }
 201
 202 static bool mount_is_rootfs(struct mntent *me) {
 203         assert(me);
 204
 205         return hasmntopt(me, "x-initrd.rootfs");
 206 }
 207
 208 static int add_mount(const char *what, const char *where, const char *type, const char *opts,
 209                      int passno, bool noauto, bool nofail, bool automount, bool isbind,
 210                      const char *pre, const char *post, const char *source) {
 211         char _cleanup_free_
 212                 *name = NULL, *unit = NULL, *lnk = NULL, *device = NULL,
 213                 *automount_name = NULL, *automount_unit = NULL;
 214         FILE _cleanup_fclose_ *f = NULL;
 215         int r;
 216
 217         assert(what);
 218         assert(where);
 219         assert(type);
 220         assert(opts);
 221         assert(source);
 222
 223         if (streq(type, "autofs"))
 224                 return 0;
 225
 226         if (!is_path(where)) {
 227                 log_warning("Mount point %s is not a valid path, ignoring.", where);
 228                 return 0;
 229         }
 230
 231         if (mount_point_is_api(where) ||
 232             mount_point_ignore(where))
 233                 return 0;
 234
 235         name = unit_name_from_path(where, ".mount");
 236         if (!name)
 237                 return log_oom();
 238
 239         unit = strjoin(arg_dest, "/", name, NULL);
 240         if (!unit)
 241                 return log_oom();
 242
 243         f = fopen(unit, "wxe");
 244         if (!f) {
 245                 if (errno == EEXIST)
 246                         log_error("Failed to create mount unit file %s, as it already exists. Duplicate entry in /etc/fstab?", unit);
 247                 else
 248                         log_error("Failed to create unit file %s: %m", unit);
 249                 return -errno;
 250         }
 251
 252         fprintf(f,
 253               "# Automatically generated by systemd-fstab-generator\n\n"
 254               "[Unit]\n"
 255               "SourcePath=%s\n"
 256               "DefaultDependencies=no\n",
 257               source);
 258
 259         if (!path_equal(where, "/")) {
 260                 if (pre)
 261                         fprintf(f,
 262                                 "After=%s\n"
 263                                 "Wants=%s\n",
 264                                 pre,
 265                                 pre);
 266                 fprintf(f,
 267                         "Conflicts=" SPECIAL_UMOUNT_TARGET "\n"
 268                         "Before=" SPECIAL_UMOUNT_TARGET "\n");
 269         }
 270
 271         if (post && !noauto && !nofail && !automount)
 272                 fprintf(f,
 273                         "Before=%s\n",
 274                         post);
 275
 276         fprintf(f,
 277                 "\n"
 278                 "[Mount]\n"
 279                 "What=%s\n"
 280                 "Where=%s\n"
 281                 "Type=%s\n"
 282                 "FsckPassNo=%i\n",
 283                 what,
 284                 where,
 285                 type,
 286                 passno);
 287
 288         if (!isempty(opts) &&
 289             !streq(opts, "defaults"))
 290                 fprintf(f,
 291                         "Options=%s\n",
 292                         opts);
 293
 294         fflush(f);
 295         if (ferror(f)) {
 296                 log_error("Failed to write unit file %s: %m", unit);
 297                 return -errno;
 298         }
 299
 300         if (!noauto) {
 301                 if (post) {
 302                         lnk = strjoin(arg_dest, "/", post, nofail || automount ? ".wants/" : ".requires/", name, NULL);
 303                         if (!lnk)
 304                                 return log_oom();
 305
 306                         mkdir_parents_label(lnk, 0755);
 307                         if (symlink(unit, lnk) < 0) {
 308                                 log_error("Failed to create symlink %s: %m", lnk);
 309                                 return -errno;
 310                         }
 311                 }
 312
 313                 if (!isbind &&
 314                     !path_equal(where, "/")) {
 315
 316                         r = device_name(what, &device);
 317                         if (r < 0)
 318                                 return r;
 319
 320                         if (r > 0) {
 321                                 free(lnk);
 322                                 lnk = strjoin(arg_dest, "/", device, ".wants/", name, NULL);
 323                                 if (!lnk)
 324                                         return log_oom();
 325
 326                                 mkdir_parents_label(lnk, 0755);
 327                                 if (symlink(unit, lnk) < 0) {
 328                                         log_error("Failed to create symlink %s: %m", lnk);
 329                                         return -errno;
 330                                 }
 331                         }
 332                 }
 333         }
 334
 335         if (automount && !path_equal(where, "/")) {
 336                 automount_name = unit_name_from_path(where, ".automount");
 337                 if (!name)
 338                         return log_oom();
 339
 340                 automount_unit = strjoin(arg_dest, "/", automount_name, NULL);
 341                 if (!automount_unit)
 342                         return log_oom();
 343
 344                 fclose(f);
 345                 f = fopen(automount_unit, "wxe");
 346                 if (!f) {
 347                         log_error("Failed to create unit file %s: %m", automount_unit);
 348                         return -errno;
 349                 }
 350
 351                 fprintf(f,
 352                         "# Automatically generated by systemd-fstab-generator\n\n"
 353                         "[Unit]\n"
 354                         "SourcePath=%s\n"
 355                         "DefaultDependencies=no\n"
 356                         "Conflicts=" SPECIAL_UMOUNT_TARGET "\n"
 357                         "Before=" SPECIAL_UMOUNT_TARGET "\n",
 358                         source);
 359
 360                 if (post)
 361                         fprintf(f,
 362                                 "Before= %s\n",
 363                                 post);
 364
 365                 fprintf(f,
 366                         "[Automount]\n"
 367                         "Where=%s\n",
 368                         where);
 369
 370                 fflush(f);
 371                 if (ferror(f)) {
 372                         log_error("Failed to write unit file %s: %m", automount_unit);
 373                         return -errno;
 374                 }
 375
 376                 free(lnk);
 377                 lnk = strjoin(arg_dest, "/", post, nofail ? ".wants/" : ".requires/", automount_name, NULL);
 378                 if (!lnk)
 379                         return log_oom();
 380
 381                 mkdir_parents_label(lnk, 0755);
 382                 if (symlink(automount_unit, lnk) < 0) {
 383                         log_error("Failed to create symlink %s: %m", lnk);
 384                         return -errno;
 385                 }
 386         }
 387
 388         return 0;
 389 }
 390
 391 static int parse_fstab(const char *prefix, bool initrd) {
 392         _cleanup_free_ char *fstab_path = NULL;
 393         FILE *f;
 394         int r = 0;
 395         struct mntent *me;
 396
 397         fstab_path = strjoin(strempty(prefix), "/etc/fstab", NULL);
 398         if (!fstab_path)
 399                 return log_oom();
 400
 401         f = setmntent(fstab_path, "r");
 402         if (!f) {
 403                 if (errno == ENOENT)
 404                         return 0;
 405
 406                 log_error("Failed to open %s/etc/fstab: %m", prefix);
 407                 return -errno;
 408         }
 409
 410         while ((me = getmntent(f))) {
 411                 char _cleanup_free_ *where = NULL, *what = NULL;
 412                 int k;
 413
 414                 if (initrd && !mount_in_initrd(me))
 415                         continue;
 416
 417                 what = fstab_node_to_udev_node(me->mnt_fsname);
 418                 where = strjoin(prefix, me->mnt_dir, NULL);
 419                 if (!what || !where) {
 420                         r = log_oom();
 421                         goto finish;
 422                 }
 423
 424                 if (is_path(where))
 425                         path_kill_slashes(where);
 426
 427                 log_debug("Found entry what=%s where=%s type=%s", what, where, me->mnt_type);
 428
 429                 if (streq(me->mnt_type, "swap"))
 430                         k = add_swap(what, me);
 431                 else {
 432                         bool noauto, nofail, automount, isbind;
 433                         const char *pre, *post;
 434
 435                         noauto = !!hasmntopt(me, "noauto");
 436                         nofail = !!hasmntopt(me, "nofail");
 437                         automount =
 438                                   hasmntopt(me, "comment=systemd.automount") ||
 439                                   hasmntopt(me, "x-systemd.automount");
 440                         isbind = mount_is_bind(me);
 441
 442                         if (initrd) {
 443                                 post = SPECIAL_INITRD_FS_TARGET;
 444                                 pre = NULL;
 445                         } else if (mount_is_rootfs(me)) {
 446                                 post = SPECIAL_INITRD_ROOT_FS_TARGET;
 447                                 pre = NULL;
 448                         } else if (mount_is_network(me)) {
 449                                 post = SPECIAL_REMOTE_FS_TARGET;
 450                                 pre = SPECIAL_REMOTE_FS_PRE_TARGET;
 451                         } else {
 452                                 post = SPECIAL_LOCAL_FS_TARGET;
 453                                 pre = SPECIAL_LOCAL_FS_PRE_TARGET;
 454                         }
 455
 456                         k = add_mount(what, where, me->mnt_type, me->mnt_opts,
 457                                      me->mnt_passno, noauto, nofail, automount,
 458                                      isbind, pre, post, fstab_path);
 459                 }
 460
 461                 if (k < 0)
 462                         r = k;
 463         }
 464
 465 finish:
 466         endmntent(f);
 467         return r;
 468 }
 469
 470 static int parse_new_root_from_proc_cmdline(void) {
 471         char *w, *state;
 472         _cleanup_free_ char *what = NULL, *type = NULL, *opts = NULL, *line = NULL;
 473         int r;
 474         size_t l;
 475
 476         r = read_one_line_file("/proc/cmdline", &line);
 477         if (r < 0) {
 478                 log_error("Failed to read /proc/cmdline, ignoring: %s", strerror(-r));
 479                 return 0;
 480         }
 481
 482         opts = strdup("ro");
 483         type = strdup("auto");
 484         if (!opts || !type)
 485                 return log_oom();
 486
 487         /* root= and roofstype= may occur more than once, the last instance should take precedence.
 488          * In the case of multiple rootflags= the arguments should be concatenated */
 489         FOREACH_WORD_QUOTED(w, l, line, state) {
 490                 char *word, *tmp_word;
 491
 492                 word = strndup(w, l);
 493                 if (!word)
 494                         return log_oom();
 495
 496                 else if (startswith(word, "root=")) {
 497                         free(what);
 498                         what = fstab_node_to_udev_node(word+5);
 499                         if (!what)
 500                                 return log_oom();
 501
 502                 } else if (startswith(word, "rootfstype=")) {
 503                         free(type);
 504                         type = strdup(word + 11);
 505                         if (!type)
 506                                 return log_oom();
 507
 508                 } else if (startswith(word, "rootflags=")) {
 509                         tmp_word = opts;
 510                         opts = strjoin(opts, ",", word + 10, NULL);
 511                         free(tmp_word);
 512                         if (!opts)
 513                                 return log_oom();
 514
 515                 } else if (streq(word, "ro") || streq(word, "rw")) {
 516                         tmp_word = opts;
 517                         opts = strjoin(opts, ",", word, NULL);
 518                         free(tmp_word);
 519                         if (!opts)
 520                                 return log_oom();
 521
 522                 }
 523
 524                 free(word);
 525         }
 526
 527         if (!what) {
 528                 log_error("Could not find a root= entry on the kernel commandline.");
 529                 return 0;
 530         }
 531
 532         if (what[0] != '/') {
 533                 log_debug("Skipping entry what=%s where=/sysroot type=%s", what, type);
 534                 return 0;
 535         }
 536
 537         log_debug("Found entry what=%s where=/sysroot type=%s", what, type);
 538         r = add_mount(what, "/sysroot", type, opts, 0, false, false, false,
 539                       false, NULL, SPECIAL_INITRD_ROOT_FS_TARGET, "/proc/cmdline");
 540
 541         return (r < 0) ? r : 0;
 542 }
 543
 544 static int parse_proc_cmdline(void) {
 545         char _cleanup_free_ *line = NULL;
 546         char *w, *state;
 547         int r;
 548         size_t l;
 549
 550         if (detect_container(NULL) > 0)
 551                 return 0;
 552
 553         r = read_one_line_file("/proc/cmdline", &line);
 554         if (r < 0) {
 555                 log_warning("Failed to read /proc/cmdline, ignoring: %s", strerror(-r));
 556                 return 0;
 557         }
 558
 559         FOREACH_WORD_QUOTED(w, l, line, state) {
 560                 char _cleanup_free_ *word = NULL;
 561
 562                 word = strndup(w, l);
 563                 if (!word)
 564                         return log_oom();
 565
 566                 if (startswith(word, "fstab=")) {
 567                         r = parse_boolean(word + 6);
 568                         if (r < 0)
 569                                 log_warning("Failed to parse fstab switch %s. Ignoring.", word + 6);
 570                         else
 571                                 arg_enabled = r;
 572
 573                 } else if (startswith(word, "rd.fstab=")) {
 574
 575                         if (in_initrd()) {
 576                                 r = parse_boolean(word + 6);
 577                                 if (r < 0)
 578                                         log_warning("Failed to parse fstab switch %s. Ignoring.", word + 6);
 579                                 else
 580                                         arg_enabled = r;
 581                         }
 582
 583                 } else if (startswith(word, "fstab.") ||
 584                            (in_initrd() && startswith(word, "rd.fstab."))) {
 585
 586                         log_warning("Unknown kernel switch %s. Ignoring.", word);
 587                 }
 588         }
 589
 590         return 0;
 591 }
 592
 593 int main(int argc, char *argv[]) {
 594         int r = 0, k, l = 0;
 595
 596         if (argc > 1 && argc != 4) {
 597                 log_error("This program takes three or no arguments.");
 598                 return EXIT_FAILURE;
 599         }
 600
 601         if (argc > 1)
 602                 arg_dest = argv[1];
 603
 604         log_set_target(LOG_TARGET_SAFE);
 605         log_parse_environment();
 606         log_open();
 607
 608         umask(0022);
 609
 610         if (parse_proc_cmdline() < 0)
 611                 return EXIT_FAILURE;
 612
 613         if (in_initrd())
 614                 r = parse_new_root_from_proc_cmdline();
 615
 616         if (!arg_enabled)
 617                 return (r < 0) ? EXIT_FAILURE : EXIT_SUCCESS;
 618
 619         k = parse_fstab(NULL, false);
 620
 621         if (in_initrd())
 622                 l = parse_fstab("/sysroot", true);
 623
 624         return (r < 0) || (k < 0) || (l < 0) ? EXIT_FAILURE : EXIT_SUCCESS;
 625 }