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         char *fstab_path;
 305         _cleanup_endmntent_ FILE *f;
 306         int r = 0;
 307         struct mntent *me;
 308
 309         fstab_path = strappenda(strempty(prefix), "/etc/fstab");
 310         f = setmntent(fstab_path, "r");
 311         if (!f) {
 312                 if (errno == ENOENT)
 313                         return 0;
 314
 315                 log_error("Failed to open %s/etc/fstab: %m", strempty(prefix));
 316                 return -errno;
 317         }
 318
 319         while ((me = getmntent(f))) {
 320                 _cleanup_free_ char *where = NULL, *what = NULL;
 321                 int k;
 322
 323                 if (initrd && !mount_in_initrd(me))
 324                         continue;
 325
 326                 what = fstab_node_to_udev_node(me->mnt_fsname);
 327                 where = strjoin(strempty(prefix), me->mnt_dir, NULL);
 328                 if (!what || !where)
 329                         return log_oom();
 330
 331                 if (is_path(where))
 332                         path_kill_slashes(where);
 333
 334                 log_debug("Found entry what=%s where=%s type=%s", what, where, me->mnt_type);
 335
 336                 if (streq(me->mnt_type, "swap"))
 337                         k = add_swap(what, me);
 338                 else {
 339                         bool noauto, nofail, automount;
 340                         const char *post;
 341
 342                         noauto = !!hasmntopt(me, "noauto");
 343                         nofail = !!hasmntopt(me, "nofail");
 344                         automount =
 345                                   hasmntopt(me, "comment=systemd.automount") ||
 346                                   hasmntopt(me, "x-systemd.automount");
 347
 348                         if (initrd) {
 349                                 post = SPECIAL_INITRD_FS_TARGET;
 350                         } else if (mount_in_initrd(me)) {
 351                                 post = SPECIAL_INITRD_ROOT_FS_TARGET;
 352                         } else if (mount_is_network(me)) {
 353                                 post = SPECIAL_REMOTE_FS_TARGET;
 354                         } else {
 355                                 post = SPECIAL_LOCAL_FS_TARGET;
 356                         }
 357
 358                         k = add_mount(what, where, me->mnt_type, me->mnt_opts,
 359                                       me->mnt_passno, noauto, nofail, automount,
 360                                       post, fstab_path);
 361                 }
 362
 363                 if (k < 0)
 364                         r = k;
 365         }
 366
 367         return r;
 368 }
 369
 370 static int parse_new_root_from_proc_cmdline(void) {
 371         _cleanup_free_ char *what = NULL, *type = NULL, *opts = NULL, *line = NULL;
 372         char *w, *state;
 373         int r;
 374         size_t l;
 375         bool noauto, nofail;
 376
 377         r = read_one_line_file("/proc/cmdline", &line);
 378         if (r < 0) {
 379                 log_error("Failed to read /proc/cmdline, ignoring: %s", strerror(-r));
 380                 return 0;
 381         }
 382
 383         opts = strdup("ro");
 384         type = strdup("auto");
 385         if (!opts || !type)
 386                 return log_oom();
 387
 388         /* root= and roofstype= may occur more than once, the last instance should take precedence.
 389          * In the case of multiple rootflags= the arguments should be concatenated */
 390         FOREACH_WORD_QUOTED(w, l, line, state) {
 391                 _cleanup_free_ char *word;
 392
 393                 word = strndup(w, l);
 394                 if (!word)
 395                         return log_oom();
 396
 397                 else if (startswith(word, "root=")) {
 398                         free(what);
 399                         what = fstab_node_to_udev_node(word+5);
 400                         if (!what)
 401                                 return log_oom();
 402
 403                 } else if (startswith(word, "rootfstype=")) {
 404                         free(type);
 405                         type = strdup(word + 11);
 406                         if (!type)
 407                                 return log_oom();
 408
 409                 } else if (startswith(word, "rootflags=")) {
 410                         char *o;
 411
 412                         o = strjoin(opts, ",", word + 10, NULL);
 413                         if (!o)
 414                                 return log_oom();
 415
 416                         free(opts);
 417                         opts = o;
 418
 419                 } else if (streq(word, "ro") || streq(word, "rw")) {
 420                         char *o;
 421
 422                         o = strjoin(opts, ",", word, NULL);
 423                         if (!o)
 424                                 return log_oom();
 425
 426                         free(opts);
 427                         opts = o;
 428                 }
 429         }
 430
 431         noauto = !!strstr(opts, "noauto");
 432         nofail = !!strstr(opts, "nofail");
 433
 434         if (!what) {
 435                 log_debug("Could not find a root= entry on the kernel commandline.");
 436                 return 0;
 437         }
 438
 439         if (what[0] != '/') {
 440                 log_debug("Skipping entry what=%s where=/sysroot type=%s", what, type);
 441                 return 0;
 442         }
 443
 444         log_debug("Found entry what=%s where=/sysroot type=%s", what, type);
 445         r = add_mount(what, "/sysroot", type, opts, 1, noauto, nofail, false,
 446                       SPECIAL_INITRD_ROOT_FS_TARGET, "/proc/cmdline");
 447
 448         return (r < 0) ? r : 0;
 449 }
 450
 451 static int parse_proc_cmdline(void) {
 452         _cleanup_free_ char *line = NULL;
 453         char *w, *state;
 454         int r;
 455         size_t l;
 456
 457         if (detect_container(NULL) > 0)
 458                 return 0;
 459
 460         r = read_one_line_file("/proc/cmdline", &line);
 461         if (r < 0) {
 462                 log_warning("Failed to read /proc/cmdline, ignoring: %s", strerror(-r));
 463                 return 0;
 464         }
 465
 466         FOREACH_WORD_QUOTED(w, l, line, state) {
 467                 _cleanup_free_ char *word = NULL;
 468
 469                 word = strndup(w, l);
 470                 if (!word)
 471                         return log_oom();
 472
 473                 if (startswith(word, "fstab=")) {
 474                         r = parse_boolean(word + 6);
 475                         if (r < 0)
 476                                 log_warning("Failed to parse fstab switch %s. Ignoring.", word + 6);
 477                         else
 478                                 arg_enabled = r;
 479
 480                 } else if (startswith(word, "rd.fstab=")) {
 481
 482                         if (in_initrd()) {
 483                                 r = parse_boolean(word + 9);
 484                                 if (r < 0)
 485                                         log_warning("Failed to parse fstab switch %s. Ignoring.", word + 9);
 486                                 else
 487                                         arg_enabled = r;
 488                         }
 489
 490                 } else if (startswith(word, "fstab.") ||
 491                            (in_initrd() && startswith(word, "rd.fstab."))) {
 492
 493                         log_warning("Unknown kernel switch %s. Ignoring.", word);
 494                 }
 495         }
 496
 497         return 0;
 498 }
 499
 500 int main(int argc, char *argv[]) {
 501         int r = 0, k, l = 0;
 502
 503         if (argc > 1 && argc != 4) {
 504                 log_error("This program takes three or no arguments.");
 505                 return EXIT_FAILURE;
 506         }
 507
 508         if (argc > 1)
 509                 arg_dest = argv[1];
 510
 511         log_set_target(LOG_TARGET_SAFE);
 512         log_parse_environment();
 513         log_open();
 514
 515         umask(0022);
 516
 517         if (parse_proc_cmdline() < 0)
 518                 return EXIT_FAILURE;
 519
 520         if (in_initrd())
 521                 r = parse_new_root_from_proc_cmdline();
 522
 523         if (!arg_enabled)
 524                 return (r < 0) ? EXIT_FAILURE : EXIT_SUCCESS;
 525
 526         k = parse_fstab(NULL, false);
 527
 528         if (in_initrd())
 529                 l = parse_fstab("/sysroot", true);
 530
 531         return (r < 0) || (k < 0) || (l < 0) ? EXIT_FAILURE : EXIT_SUCCESS;
 532 }