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 mount_find_pri(struct mntent *me, int *ret) {
  42         char *end, *pri;
  43         unsigned long r;
  44
  45         assert(me);
  46         assert(ret);
  47
  48         pri = hasmntopt(me, "pri");
  49         if (!pri)
  50                 return 0;
  51
  52         pri += 4;
  53
  54         errno = 0;
  55         r = strtoul(pri, &end, 10);
  56         if (errno > 0)
  57                 return -errno;
  58
  59         if (end == pri || (*end != ',' && *end != 0))
  60                 return -EINVAL;
  61
  62         *ret = (int) r;
  63         return 1;
  64 }
  65
  66 static int add_swap(const char *what, struct mntent *me) {
  67         _cleanup_free_ char *name = NULL, *unit = NULL, *lnk = NULL;
  68         _cleanup_fclose_ FILE *f = NULL;
  69         bool noauto;
  70         int r, pri = -1;
  71
  72         assert(what);
  73         assert(me);
  74
  75         r = mount_find_pri(me, &pri);
  76         if (r < 0) {
  77                 log_error("Failed to parse priority");
  78                 return pri;
  79         }
  80
  81         noauto = !!hasmntopt(me, "noauto");
  82
  83         name = unit_name_from_path(what, ".swap");
  84         if (!name)
  85                 return log_oom();
  86
  87         unit = strjoin(arg_dest, "/", name, NULL);
  88         if (!unit)
  89                 return log_oom();
  90
  91         f = fopen(unit, "wxe");
  92         if (!f) {
  93                 if (errno == EEXIST)
  94                         log_error("Failed to create swap unit file %s, as it already exists. Duplicate entry in /etc/fstab?", unit);
  95                 else
  96                         log_error("Failed to create unit file %s: %m", unit);
  97                 return -errno;
  98         }
  99
 100         fprintf(f,
 101                 "# Automatically generated by systemd-fstab-generator\n\n"
 102                 "[Unit]\n"
 103                 "SourcePath=/etc/fstab\n\n"
 104                 "[Swap]\n"
 105                 "What=%s\n",
 106                 what);
 107
 108         if (pri >= 0)
 109                 fprintf(f,
 110                         "Priority=%i\n",
 111                         pri);
 112
 113         fflush(f);
 114         if (ferror(f)) {
 115                 log_error("Failed to write unit file %s: %m", unit);
 116                 return -errno;
 117         }
 118
 119         if (!noauto) {
 120                 lnk = strjoin(arg_dest, "/" SPECIAL_SWAP_TARGET ".wants/", name, NULL);
 121                 if (!lnk)
 122                         return log_oom();
 123
 124                 mkdir_parents_label(lnk, 0755);
 125                 if (symlink(unit, lnk) < 0) {
 126                         log_error("Failed to create symlink %s: %m", lnk);
 127                         return -errno;
 128                 }
 129         }
 130
 131         return 0;
 132 }
 133
 134 static bool mount_is_network(struct mntent *me) {
 135         assert(me);
 136
 137         return
 138                 hasmntopt(me, "_netdev") ||
 139                 fstype_is_network(me->mnt_type);
 140 }
 141
 142 static bool mount_in_initrd(struct mntent *me) {
 143         assert(me);
 144
 145         return
 146                 hasmntopt(me, "x-initrd.mount") ||
 147                 streq(me->mnt_dir, "/usr");
 148 }
 149
 150 static int add_mount(
 151                 const char *what,
 152                 const char *where,
 153                 const char *type,
 154                 const char *opts,
 155                 int passno,
 156                 bool noauto,
 157                 bool nofail,
 158                 bool automount,
 159                 const char *post,
 160                 const char *source) {
 161         _cleanup_free_ char
 162                 *name = NULL, *unit = NULL, *lnk = NULL,
 163                 *automount_name = NULL, *automount_unit = NULL;
 164         _cleanup_fclose_ FILE *f = NULL;
 165
 166         assert(what);
 167         assert(where);
 168         assert(type);
 169         assert(opts);
 170         assert(source);
 171
 172         if (streq(type, "autofs"))
 173                 return 0;
 174
 175         if (!is_path(where)) {
 176                 log_warning("Mount point %s is not a valid path, ignoring.", where);
 177                 return 0;
 178         }
 179
 180         if (mount_point_is_api(where) ||
 181             mount_point_ignore(where))
 182                 return 0;
 183
 184         name = unit_name_from_path(where, ".mount");
 185         if (!name)
 186                 return log_oom();
 187
 188         unit = strjoin(arg_dest, "/", name, NULL);
 189         if (!unit)
 190                 return log_oom();
 191
 192         f = fopen(unit, "wxe");
 193         if (!f) {
 194                 if (errno == EEXIST)
 195                         log_error("Failed to create mount unit file %s, as it already exists. Duplicate entry in /etc/fstab?", unit);
 196                 else
 197                         log_error("Failed to create unit file %s: %m", unit);
 198                 return -errno;
 199         }
 200
 201         fprintf(f,
 202               "# Automatically generated by systemd-fstab-generator\n\n"
 203               "[Unit]\n"
 204               "SourcePath=%s\n",
 205               source);
 206
 207         if (post && !noauto && !nofail && !automount)
 208                 fprintf(f,
 209                         "Before=%s\n",
 210                         post);
 211
 212         fprintf(f,
 213                 "\n"
 214                 "[Mount]\n"
 215                 "What=%s\n"
 216                 "Where=%s\n"
 217                 "Type=%s\n"
 218                 "FsckPassNo=%i\n",
 219                 what,
 220                 where,
 221                 type,
 222                 passno);
 223
 224         if (!isempty(opts) &&
 225             !streq(opts, "defaults"))
 226                 fprintf(f,
 227                         "Options=%s\n",
 228                         opts);
 229
 230         fflush(f);
 231         if (ferror(f)) {
 232                 log_error("Failed to write unit file %s: %m", unit);
 233                 return -errno;
 234         }
 235
 236         if (!noauto) {
 237                 if (post) {
 238                         lnk = strjoin(arg_dest, "/", post, nofail || automount ? ".wants/" : ".requires/", name, NULL);
 239                         if (!lnk)
 240                                 return log_oom();
 241
 242                         mkdir_parents_label(lnk, 0755);
 243                         if (symlink(unit, lnk) < 0) {
 244                                 log_error("Failed to create symlink %s: %m", lnk);
 245                                 return -errno;
 246                         }
 247                 }
 248         }
 249
 250         if (automount && !path_equal(where, "/")) {
 251                 automount_name = unit_name_from_path(where, ".automount");
 252                 if (!automount_name)
 253                         return log_oom();
 254
 255                 automount_unit = strjoin(arg_dest, "/", automount_name, NULL);
 256                 if (!automount_unit)
 257                         return log_oom();
 258
 259                 fclose(f);
 260                 f = fopen(automount_unit, "wxe");
 261                 if (!f) {
 262                         log_error("Failed to create unit file %s: %m", automount_unit);
 263                         return -errno;
 264                 }
 265
 266                 fprintf(f,
 267                         "# Automatically generated by systemd-fstab-generator\n\n"
 268                         "[Unit]\n"
 269                         "SourcePath=%s\n",
 270                         source);
 271
 272                 if (post)
 273                         fprintf(f,
 274                                 "Before= %s\n",
 275                                 post);
 276
 277                 fprintf(f,
 278                         "[Automount]\n"
 279                         "Where=%s\n",
 280                         where);
 281
 282                 fflush(f);
 283                 if (ferror(f)) {
 284                         log_error("Failed to write unit file %s: %m", automount_unit);
 285                         return -errno;
 286                 }
 287
 288                 free(lnk);
 289                 lnk = strjoin(arg_dest, "/", post, nofail ? ".wants/" : ".requires/", automount_name, NULL);
 290                 if (!lnk)
 291                         return log_oom();
 292
 293                 mkdir_parents_label(lnk, 0755);
 294                 if (symlink(automount_unit, lnk) < 0) {
 295                         log_error("Failed to create symlink %s: %m", lnk);
 296                         return -errno;
 297                 }
 298         }
 299
 300         return 0;
 301 }
 302
 303 static int parse_fstab(const char *prefix, bool initrd) {
 304         _cleanup_free_ char *fstab_path = NULL;
 305         FILE *f;
 306         int r = 0;
 307         struct mntent *me;
 308
 309         fstab_path = strjoin(strempty(prefix), "/etc/fstab", NULL);
 310         if (!fstab_path)
 311                 return log_oom();
 312
 313         f = setmntent(fstab_path, "r");
 314         if (!f) {
 315                 if (errno == ENOENT)
 316                         return 0;
 317
 318                 log_error("Failed to open %s/etc/fstab: %m", strempty(prefix));
 319                 return -errno;
 320         }
 321
 322         while ((me = getmntent(f))) {
 323                 _cleanup_free_ char *where = NULL, *what = NULL;
 324                 int k;
 325
 326                 if (initrd && !mount_in_initrd(me))
 327                         continue;
 328
 329                 what = fstab_node_to_udev_node(me->mnt_fsname);
 330                 where = strjoin(strempty(prefix), me->mnt_dir, NULL);
 331                 if (!what || !where) {
 332                         r = log_oom();
 333                         goto finish;
 334                 }
 335
 336                 if (is_path(where))
 337                         path_kill_slashes(where);
 338
 339                 log_debug("Found entry what=%s where=%s type=%s", what, where, me->mnt_type);
 340
 341                 if (streq(me->mnt_type, "swap"))
 342                         k = add_swap(what, me);
 343                 else {
 344                         bool noauto, nofail, automount;
 345                         const char *post;
 346
 347                         noauto = !!hasmntopt(me, "noauto");
 348                         nofail = !!hasmntopt(me, "nofail");
 349                         automount =
 350                                   hasmntopt(me, "comment=systemd.automount") ||
 351                                   hasmntopt(me, "x-systemd.automount");
 352
 353                         if (initrd) {
 354                                 post = SPECIAL_INITRD_FS_TARGET;
 355                         } else if (mount_in_initrd(me)) {
 356                                 post = SPECIAL_INITRD_ROOT_FS_TARGET;
 357                         } else if (mount_is_network(me)) {
 358                                 post = SPECIAL_REMOTE_FS_TARGET;
 359                         } else {
 360                                 post = SPECIAL_LOCAL_FS_TARGET;
 361                         }
 362
 363                         k = add_mount(what, where, me->mnt_type, me->mnt_opts,
 364                                       me->mnt_passno, noauto, nofail, automount,
 365                                       post, fstab_path);
 366                 }
 367
 368                 if (k < 0)
 369                         r = k;
 370         }
 371
 372 finish:
 373         endmntent(f);
 374         return r;
 375 }
 376
 377 static int parse_new_root_from_proc_cmdline(void) {
 378         _cleanup_free_ char *what = NULL, *type = NULL, *opts = NULL, *line = NULL;
 379         char *w, *state;
 380         int r;
 381         size_t l;
 382         bool noauto, nofail;
 383
 384         r = read_one_line_file("/proc/cmdline", &line);
 385         if (r < 0) {
 386                 log_error("Failed to read /proc/cmdline, ignoring: %s", strerror(-r));
 387                 return 0;
 388         }
 389
 390         opts = strdup("ro");
 391         type = strdup("auto");
 392         if (!opts || !type)
 393                 return log_oom();
 394
 395         /* root= and roofstype= may occur more than once, the last instance should take precedence.
 396          * In the case of multiple rootflags= the arguments should be concatenated */
 397         FOREACH_WORD_QUOTED(w, l, line, state) {
 398                 _cleanup_free_ char *word;
 399
 400                 word = strndup(w, l);
 401                 if (!word)
 402                         return log_oom();
 403
 404                 else if (startswith(word, "root=")) {
 405                         free(what);
 406                         what = fstab_node_to_udev_node(word+5);
 407                         if (!what)
 408                                 return log_oom();
 409
 410                 } else if (startswith(word, "rootfstype=")) {
 411                         free(type);
 412                         type = strdup(word + 11);
 413                         if (!type)
 414                                 return log_oom();
 415
 416                 } else if (startswith(word, "rootflags=")) {
 417                         char *o;
 418
 419                         o = strjoin(opts, ",", word + 10, NULL);
 420                         if (!o)
 421                                 return log_oom();
 422
 423                         free(opts);
 424                         opts = o;
 425
 426                 } else if (streq(word, "ro") || streq(word, "rw")) {
 427                         char *o;
 428
 429                         o = strjoin(opts, ",", word, NULL);
 430                         if (!o)
 431                                 return log_oom();
 432
 433                         free(opts);
 434                         opts = o;
 435                 }
 436         }
 437
 438         noauto = !!strstr(opts, "noauto");
 439         nofail = !!strstr(opts, "nofail");
 440
 441         if (!what) {
 442                 log_debug("Could not find a root= entry on the kernel commandline.");
 443                 return 0;
 444         }
 445
 446         if (what[0] != '/') {
 447                 log_debug("Skipping entry what=%s where=/sysroot type=%s", what, type);
 448                 return 0;
 449         }
 450
 451         log_debug("Found entry what=%s where=/sysroot type=%s", what, type);
 452         r = add_mount(what, "/sysroot", type, opts, 0, noauto, nofail, false,
 453                       SPECIAL_INITRD_ROOT_FS_TARGET, "/proc/cmdline");
 454
 455         return (r < 0) ? r : 0;
 456 }
 457
 458 static int parse_proc_cmdline(void) {
 459         _cleanup_free_ char *line = NULL;
 460         char *w, *state;
 461         int r;
 462         size_t l;
 463
 464         if (detect_container(NULL) > 0)
 465                 return 0;
 466
 467         r = read_one_line_file("/proc/cmdline", &line);
 468         if (r < 0) {
 469                 log_warning("Failed to read /proc/cmdline, ignoring: %s", strerror(-r));
 470                 return 0;
 471         }
 472
 473         FOREACH_WORD_QUOTED(w, l, line, state) {
 474                 _cleanup_free_ char *word = NULL;
 475
 476                 word = strndup(w, l);
 477                 if (!word)
 478                         return log_oom();
 479
 480                 if (startswith(word, "fstab=")) {
 481                         r = parse_boolean(word + 6);
 482                         if (r < 0)
 483                                 log_warning("Failed to parse fstab switch %s. Ignoring.", word + 6);
 484                         else
 485                                 arg_enabled = r;
 486
 487                 } else if (startswith(word, "rd.fstab=")) {
 488
 489                         if (in_initrd()) {
 490                                 r = parse_boolean(word + 9);
 491                                 if (r < 0)
 492                                         log_warning("Failed to parse fstab switch %s. Ignoring.", word + 9);
 493                                 else
 494                                         arg_enabled = r;
 495                         }
 496
 497                 } else if (startswith(word, "fstab.") ||
 498                            (in_initrd() && startswith(word, "rd.fstab."))) {
 499
 500                         log_warning("Unknown kernel switch %s. Ignoring.", word);
 501                 }
 502         }
 503
 504         return 0;
 505 }
 506
 507 int main(int argc, char *argv[]) {
 508         int r = 0, k, l = 0;
 509
 510         if (argc > 1 && argc != 4) {
 511                 log_error("This program takes three or no arguments.");
 512                 return EXIT_FAILURE;
 513         }
 514
 515         if (argc > 1)
 516                 arg_dest = argv[1];
 517
 518         log_set_target(LOG_TARGET_SAFE);
 519         log_parse_environment();
 520         log_open();
 521
 522         umask(0022);
 523
 524         if (parse_proc_cmdline() < 0)
 525                 return EXIT_FAILURE;
 526
 527         if (in_initrd())
 528                 r = parse_new_root_from_proc_cmdline();
 529
 530         if (!arg_enabled)
 531                 return (r < 0) ? EXIT_FAILURE : EXIT_SUCCESS;
 532
 533         k = parse_fstab(NULL, false);
 534
 535         if (in_initrd())
 536                 l = parse_fstab("/sysroot", true);
 537
 538         return (r < 0) || (k < 0) || (l < 0) ? EXIT_FAILURE : EXIT_SUCCESS;
 539 }