src/fstab-generator/fstab-generator.c

   1 /* SPDX-License-Identifier: LGPL-2.1+ */
   2
   3 #include <errno.h>
   4 #include <mntent.h>
   5 #include <stdio.h>
   6 #include <string.h>
   7 #include <unistd.h>
   8 #include <stdio_ext.h>
   9
  10 #include "alloc-util.h"
  11 #include "fd-util.h"
  12 #include "fileio.h"
  13 #include "fs-util.h"
  14 #include "fstab-util.h"
  15 #include "generator.h"
  16 #include "log.h"
  17 #include "main-func.h"
  18 #include "mkdir.h"
  19 #include "mount-setup.h"
  20 #include "mount-util.h"
  21 #include "mountpoint-util.h"
  22 #include "parse-util.h"
  23 #include "path-util.h"
  24 #include "proc-cmdline.h"
  25 #include "special.h"
  26 #include "specifier.h"
  27 #include "stat-util.h"
  28 #include "string-util.h"
  29 #include "strv.h"
  30 #include "unit-name.h"
  31 #include "util.h"
  32 #include "virt.h"
  33 #include "volatile-util.h"
  34
  35 typedef enum MountpointFlags {
  36         NOAUTO    = 1 << 0,
  37         NOFAIL    = 1 << 1,
  38         AUTOMOUNT = 1 << 2,
  39         MAKEFS    = 1 << 3,
  40         GROWFS    = 1 << 4,
  41 } MountpointFlags;
  42
  43 static const char *arg_dest = NULL;
  44 static const char *arg_dest_late = NULL;
  45 static bool arg_fstab_enabled = true;
  46 static char *arg_root_what = NULL;
  47 static char *arg_root_fstype = NULL;
  48 static char *arg_root_options = NULL;
  49 static char *arg_root_hash = NULL;
  50 static int arg_root_rw = -1;
  51 static char *arg_usr_what = NULL;
  52 static char *arg_usr_fstype = NULL;
  53 static char *arg_usr_options = NULL;
  54 static VolatileMode arg_volatile_mode = _VOLATILE_MODE_INVALID;
  55
  56 STATIC_DESTRUCTOR_REGISTER(arg_root_what, freep);
  57 STATIC_DESTRUCTOR_REGISTER(arg_root_fstype, freep);
  58 STATIC_DESTRUCTOR_REGISTER(arg_root_options, freep);
  59 STATIC_DESTRUCTOR_REGISTER(arg_root_hash, freep);
  60 STATIC_DESTRUCTOR_REGISTER(arg_usr_what, freep);
  61 STATIC_DESTRUCTOR_REGISTER(arg_usr_fstype, freep);
  62 STATIC_DESTRUCTOR_REGISTER(arg_usr_options, freep);
  63
  64 static int write_options(FILE *f, const char *options) {
  65         _cleanup_free_ char *o = NULL;
  66
  67         if (isempty(options))
  68                 return 0;
  69
  70         if (streq(options, "defaults"))
  71                 return 0;
  72
  73         o = specifier_escape(options);
  74         if (!o)
  75                 return log_oom();
  76
  77         fprintf(f, "Options=%s\n", o);
  78         return 1;
  79 }
  80
  81 static int write_what(FILE *f, const char *what) {
  82         _cleanup_free_ char *w = NULL;
  83
  84         w = specifier_escape(what);
  85         if (!w)
  86                 return log_oom();
  87
  88         fprintf(f, "What=%s\n", w);
  89         return 1;
  90 }
  91
  92 static int add_swap(
  93                 const char *what,
  94                 struct mntent *me,
  95                 MountpointFlags flags) {
  96
  97         _cleanup_free_ char *name = NULL;
  98         _cleanup_fclose_ FILE *f = NULL;
  99         int r;
 100
 101         assert(what);
 102         assert(me);
 103
 104         if (access("/proc/swaps", F_OK) < 0) {
 105                 log_info("Swap not supported, ignoring fstab swap entry for %s.", what);
 106                 return 0;
 107         }
 108
 109         if (detect_container() > 0) {
 110                 log_info("Running in a container, ignoring fstab swap entry for %s.", what);
 111                 return 0;
 112         }
 113
 114         r = unit_name_from_path(what, ".swap", &name);
 115         if (r < 0)
 116                 return log_error_errno(r, "Failed to generate unit name: %m");
 117
 118         r = generator_open_unit_file(arg_dest, "/etc/fstab", name, &f);
 119         if (r < 0)
 120                 return r;
 121
 122         fputs("# Automatically generated by systemd-fstab-generator\n\n"
 123               "[Unit]\n"
 124               "SourcePath=/etc/fstab\n"
 125               "Documentation=man:fstab(5) man:systemd-fstab-generator(8)\n\n"
 126               "[Swap]\n", f);
 127
 128         r = write_what(f, what);
 129         if (r < 0)
 130                 return r;
 131
 132         r = write_options(f, me->mnt_opts);
 133         if (r < 0)
 134                 return r;
 135
 136         r = fflush_and_check(f);
 137         if (r < 0)
 138                 return log_error_errno(r, "Failed to write unit file %s: %m", name);
 139
 140         /* use what as where, to have a nicer error message */
 141         r = generator_write_timeouts(arg_dest, what, what, me->mnt_opts, NULL);
 142         if (r < 0)
 143                 return r;
 144
 145         if (flags & MAKEFS) {
 146                 r = generator_hook_up_mkswap(arg_dest, what);
 147                 if (r < 0)
 148                         return r;
 149         }
 150
 151         if (flags & GROWFS)
 152                 /* TODO: swap devices must be wiped and recreated */
 153                 log_warning("%s: growing swap devices is currently unsupported.", what);
 154
 155         if (!(flags & NOAUTO)) {
 156                 r = generator_add_symlink(arg_dest, SPECIAL_SWAP_TARGET,
 157                                           (flags & NOFAIL) ? "wants" : "requires", name);
 158                 if (r < 0)
 159                         return r;
 160         }
 161
 162         return 0;
 163 }
 164
 165 static bool mount_is_network(struct mntent *me) {
 166         assert(me);
 167
 168         return fstab_test_option(me->mnt_opts, "_netdev\0") ||
 169                fstype_is_network(me->mnt_type);
 170 }
 171
 172 static bool mount_in_initrd(struct mntent *me) {
 173         assert(me);
 174
 175         return fstab_test_option(me->mnt_opts, "x-initrd.mount\0") ||
 176                streq(me->mnt_dir, "/usr");
 177 }
 178
 179 static int write_timeout(FILE *f, const char *where, const char *opts,
 180                          const char *filter, const char *variable) {
 181         _cleanup_free_ char *timeout = NULL;
 182         char timespan[FORMAT_TIMESPAN_MAX];
 183         usec_t u;
 184         int r;
 185
 186         r = fstab_filter_options(opts, filter, NULL, &timeout, NULL);
 187         if (r < 0)
 188                 return log_warning_errno(r, "Failed to parse options: %m");
 189         if (r == 0)
 190                 return 0;
 191
 192         r = parse_sec_fix_0(timeout, &u);
 193         if (r < 0) {
 194                 log_warning("Failed to parse timeout for %s, ignoring: %s", where, timeout);
 195                 return 0;
 196         }
 197
 198         fprintf(f, "%s=%s\n", variable, format_timespan(timespan, sizeof(timespan), u, 0));
 199
 200         return 0;
 201 }
 202
 203 static int write_idle_timeout(FILE *f, const char *where, const char *opts) {
 204         return write_timeout(f, where, opts,
 205                              "x-systemd.idle-timeout\0", "TimeoutIdleSec");
 206 }
 207
 208 static int write_mount_timeout(FILE *f, const char *where, const char *opts) {
 209         return write_timeout(f, where, opts,
 210                              "x-systemd.mount-timeout\0", "TimeoutSec");
 211 }
 212
 213 static int write_dependency(FILE *f, const char *opts,
 214                 const char *filter, const char *format) {
 215         _cleanup_strv_free_ char **names = NULL, **units = NULL;
 216         _cleanup_free_ char *res = NULL;
 217         char **s;
 218         int r;
 219
 220         assert(f);
 221         assert(opts);
 222
 223         r = fstab_extract_values(opts, filter, &names);
 224         if (r < 0)
 225                 return log_warning_errno(r, "Failed to parse options: %m");
 226         if (r == 0)
 227                 return 0;
 228
 229         STRV_FOREACH(s, names) {
 230                 char *x;
 231
 232                 r = unit_name_mangle_with_suffix(*s, 0, ".mount", &x);
 233                 if (r < 0)
 234                         return log_error_errno(r, "Failed to generate unit name: %m");
 235                 r = strv_consume(&units, x);
 236                 if (r < 0)
 237                         return log_oom();
 238         }
 239
 240         if (units) {
 241                 res = strv_join(units, " ");
 242                 if (!res)
 243                         return log_oom();
 244 #pragma GCC diagnostic push
 245 #pragma GCC diagnostic ignored "-Wformat-nonliteral"
 246                 fprintf(f, format, res);
 247 #pragma GCC diagnostic pop
 248         }
 249
 250         return 0;
 251 }
 252
 253 static int write_after(FILE *f, const char *opts) {
 254         return write_dependency(f, opts, "x-systemd.after", "After=%1$s\n");
 255 }
 256
 257 static int write_requires_after(FILE *f, const char *opts) {
 258         return write_dependency(f, opts,
 259                                 "x-systemd.requires", "After=%1$s\nRequires=%1$s\n");
 260 }
 261
 262 static int write_before(FILE *f, const char *opts) {
 263         return write_dependency(f, opts,
 264                                 "x-systemd.before", "Before=%1$s\n");
 265 }
 266
 267 static int write_requires_mounts_for(FILE *f, const char *opts) {
 268         _cleanup_strv_free_ char **paths = NULL, **paths_escaped = NULL;
 269         _cleanup_free_ char *res = NULL;
 270         int r;
 271
 272         assert(f);
 273         assert(opts);
 274
 275         r = fstab_extract_values(opts, "x-systemd.requires-mounts-for", &paths);
 276         if (r < 0)
 277                 return log_warning_errno(r, "Failed to parse options: %m");
 278         if (r == 0)
 279                 return 0;
 280
 281         r = specifier_escape_strv(paths, &paths_escaped);
 282         if (r < 0)
 283                 return log_error_errno(r, "Failed to escape paths: %m");
 284
 285         res = strv_join(paths_escaped, " ");
 286         if (!res)
 287                 return log_oom();
 288
 289         fprintf(f, "RequiresMountsFor=%s\n", res);
 290
 291         return 0;
 292 }
 293
 294 static int add_mount(
 295                 const char *dest,
 296                 const char *what,
 297                 const char *where,
 298                 const char *original_where,
 299                 const char *fstype,
 300                 const char *opts,
 301                 int passno,
 302                 MountpointFlags flags,
 303                 const char *post,
 304                 const char *source) {
 305
 306         _cleanup_free_ char
 307                 *name = NULL,
 308                 *automount_name = NULL,
 309                 *filtered = NULL,
 310                 *where_escaped = NULL;
 311         _cleanup_fclose_ FILE *f = NULL;
 312         int r;
 313
 314         assert(what);
 315         assert(where);
 316         assert(opts);
 317         assert(post);
 318         assert(source);
 319
 320         if (streq_ptr(fstype, "autofs"))
 321                 return 0;
 322
 323         if (!is_path(where)) {
 324                 log_warning("Mount point %s is not a valid path, ignoring.", where);
 325                 return 0;
 326         }
 327
 328         if (mount_point_is_api(where) ||
 329             mount_point_ignore(where))
 330                 return 0;
 331
 332         if (path_equal(where, "/")) {
 333                 if (flags & NOAUTO)
 334                         log_warning("Ignoring \"noauto\" for root device");
 335                 if (flags & NOFAIL)
 336                         log_warning("Ignoring \"nofail\" for root device");
 337                 if (flags & AUTOMOUNT)
 338                         log_warning("Ignoring automount option for root device");
 339
 340                 SET_FLAG(flags, NOAUTO | NOFAIL | AUTOMOUNT, false);
 341         }
 342
 343         r = unit_name_from_path(where, ".mount", &name);
 344         if (r < 0)
 345                 return log_error_errno(r, "Failed to generate unit name: %m");
 346
 347         r = generator_open_unit_file(dest, "/etc/fstab", name, &f);
 348         if (r < 0)
 349                 return r;
 350
 351         fprintf(f,
 352                 "[Unit]\n"
 353                 "SourcePath=%s\n"
 354                 "Documentation=man:fstab(5) man:systemd-fstab-generator(8)\n",
 355                 source);
 356
 357         if (STRPTR_IN_SET(fstype, "nfs", "nfs4") && !(flags & AUTOMOUNT) &&
 358             fstab_test_yes_no_option(opts, "bg\0" "fg\0")) {
 359                 /* The default retry timeout that mount.nfs uses for 'bg' mounts
 360                  * is 10000 minutes, where as it uses 2 minutes for 'fg' mounts.
 361                  * As we are making  'bg' mounts look like an 'fg' mount to
 362                  * mount.nfs (so systemd can manage the job-control aspects of 'bg'),
 363                  * we need to explicitly preserve that default, and also ensure
 364                  * the systemd mount-timeout doesn't interfere.
 365                  * By placing these options first, they can be over-ridden by
 366                  * settings in /etc/fstab. */
 367                 opts = strjoina("x-systemd.mount-timeout=infinity,retry=10000,", opts, ",fg");
 368                 SET_FLAG(flags, NOFAIL, true);
 369         }
 370
 371         if (!(flags & NOFAIL) && !(flags & AUTOMOUNT))
 372                 fprintf(f, "Before=%s\n", post);
 373
 374         if (!(flags & AUTOMOUNT) && opts) {
 375                  r = write_after(f, opts);
 376                  if (r < 0)
 377                          return r;
 378                  r = write_requires_after(f, opts);
 379                  if (r < 0)
 380                          return r;
 381                  r = write_before(f, opts);
 382                  if (r < 0)
 383                          return r;
 384                  r = write_requires_mounts_for(f, opts);
 385                  if (r < 0)
 386                          return r;
 387         }
 388
 389         if (passno != 0) {
 390                 r = generator_write_fsck_deps(f, dest, what, where, fstype);
 391                 if (r < 0)
 392                         return r;
 393         }
 394
 395         fprintf(f, "\n[Mount]\n");
 396         if (original_where)
 397                 fprintf(f, "# Canonicalized from %s\n", original_where);
 398
 399         where_escaped = specifier_escape(where);
 400         if (!where_escaped)
 401                 return log_oom();
 402         fprintf(f, "Where=%s\n", where_escaped);
 403
 404         r = write_what(f, what);
 405         if (r < 0)
 406                 return r;
 407
 408         if (!isempty(fstype) && !streq(fstype, "auto")) {
 409                 _cleanup_free_ char *t;
 410
 411                 t = specifier_escape(fstype);
 412                 if (!t)
 413                         return -ENOMEM;
 414
 415                 fprintf(f, "Type=%s\n", t);
 416         }
 417
 418         r = generator_write_timeouts(dest, what, where, opts, &filtered);
 419         if (r < 0)
 420                 return r;
 421
 422         r = generator_write_device_deps(dest, what, where, opts);
 423         if (r < 0)
 424                 return r;
 425
 426         r = write_mount_timeout(f, where, opts);
 427         if (r < 0)
 428                 return r;
 429
 430         r = write_options(f, filtered);
 431         if (r < 0)
 432                 return r;
 433
 434         r = fflush_and_check(f);
 435         if (r < 0)
 436                 return log_error_errno(r, "Failed to write unit file %s: %m", name);
 437
 438         if (flags & MAKEFS) {
 439                 r = generator_hook_up_mkfs(dest, what, where, fstype);
 440                 if (r < 0)
 441                         return r;
 442         }
 443
 444         if (flags & GROWFS) {
 445                 r = generator_hook_up_growfs(dest, where, post);
 446                 if (r < 0)
 447                         return r;
 448         }
 449
 450         if (!(flags & NOAUTO) && !(flags & AUTOMOUNT)) {
 451                 r = generator_add_symlink(dest, post,
 452                                           (flags & NOFAIL) ? "wants" : "requires", name);
 453                 if (r < 0)
 454                         return r;
 455         }
 456
 457         if (flags & AUTOMOUNT) {
 458                 r = unit_name_from_path(where, ".automount", &automount_name);
 459                 if (r < 0)
 460                         return log_error_errno(r, "Failed to generate unit name: %m");
 461
 462                 fclose(f);
 463
 464                 r = generator_open_unit_file(dest, "/etc/fstab", automount_name, &f);
 465                 if (r < 0)
 466                         return r;
 467
 468                 fprintf(f,
 469                         "[Unit]\n"
 470                         "SourcePath=%s\n"
 471                         "Documentation=man:fstab(5) man:systemd-fstab-generator(8)\n",
 472                         source);
 473
 474                 fprintf(f, "Before=%s\n", post);
 475
 476                 if (opts) {
 477                         r = write_after(f, opts);
 478                         if (r < 0)
 479                                 return r;
 480                         r = write_requires_after(f, opts);
 481                         if (r < 0)
 482                                 return r;
 483                         r = write_before(f, opts);
 484                         if (r < 0)
 485                                 return r;
 486                         r = write_requires_mounts_for(f, opts);
 487                         if (r < 0)
 488                                 return r;
 489                 }
 490
 491                 fprintf(f,
 492                         "\n"
 493                         "[Automount]\n"
 494                         "Where=%s\n",
 495                         where_escaped);
 496
 497                 r = write_idle_timeout(f, where, opts);
 498                 if (r < 0)
 499                         return r;
 500
 501                 r = fflush_and_check(f);
 502                 if (r < 0)
 503                         return log_error_errno(r, "Failed to write unit file %s: %m", automount_name);
 504
 505                 r = generator_add_symlink(dest, post,
 506                                           (flags & NOFAIL) ? "wants" : "requires", automount_name);
 507                 if (r < 0)
 508                         return r;
 509         }
 510
 511         return 0;
 512 }
 513
 514 static int parse_fstab(bool initrd) {
 515         _cleanup_endmntent_ FILE *f = NULL;
 516         const char *fstab_path;
 517         struct mntent *me;
 518         int r = 0;
 519
 520         fstab_path = initrd ? "/sysroot/etc/fstab" : "/etc/fstab";
 521         log_debug("Parsing %s...", fstab_path);
 522
 523         f = setmntent(fstab_path, "re");
 524         if (!f) {
 525                 if (errno == ENOENT)
 526                         return 0;
 527
 528                 return log_error_errno(errno, "Failed to open %s: %m", fstab_path);
 529         }
 530
 531         while ((me = getmntent(f))) {
 532                 _cleanup_free_ char *where = NULL, *what = NULL, *canonical_where = NULL;
 533                 bool makefs, growfs, noauto, nofail;
 534                 int k;
 535
 536                 if (initrd && !mount_in_initrd(me))
 537                         continue;
 538
 539                 what = fstab_node_to_udev_node(me->mnt_fsname);
 540                 if (!what)
 541                         return log_oom();
 542
 543                 if (is_device_path(what) && path_is_read_only_fs("/sys") > 0) {
 544                         log_info("Running in a container, ignoring fstab device entry for %s.", what);
 545                         continue;
 546                 }
 547
 548                 where = strdup(me->mnt_dir);
 549                 if (!where)
 550                         return log_oom();
 551
 552                 if (is_path(where)) {
 553                         path_simplify(where, false);
 554
 555                         /* Follow symlinks here; see 5261ba901845c084de5a8fd06500ed09bfb0bd80 which makes sense for
 556                          * mount units, but causes problems since it historically worked to have symlinks in e.g.
 557                          * /etc/fstab. So we canonicalize here. Note that we use CHASE_NONEXISTENT to handle the case
 558                          * where a symlink refers to another mount target; this works assuming the sub-mountpoint
 559                          * target is the final directory. */
 560                         r = chase_symlinks(where, initrd ? "/sysroot" : NULL,
 561                                            CHASE_PREFIX_ROOT | CHASE_NONEXISTENT,
 562                                            &canonical_where);
 563                         if (r < 0) /* If we can't canonicalize we continue on as if it wasn't a symlink */
 564                                 log_debug_errno(r, "Failed to read symlink target for %s, ignoring: %m", where);
 565                         else if (streq(canonical_where, where)) /* If it was fully canonicalized, suppress the change */
 566                                 canonical_where = mfree(canonical_where);
 567                         else
 568                                 log_debug("Canonicalized what=%s where=%s to %s", what, where, canonical_where);
 569                 }
 570
 571                 makefs = fstab_test_option(me->mnt_opts, "x-systemd.makefs\0");
 572                 growfs = fstab_test_option(me->mnt_opts, "x-systemd.growfs\0");
 573                 noauto = fstab_test_yes_no_option(me->mnt_opts, "noauto\0" "auto\0");
 574                 nofail = fstab_test_yes_no_option(me->mnt_opts, "nofail\0" "fail\0");
 575
 576                 log_debug("Found entry what=%s where=%s type=%s makefs=%s growfs=%s noauto=%s nofail=%s",
 577                           what, where, me->mnt_type,
 578                           yes_no(makefs), yes_no(growfs),
 579                           yes_no(noauto), yes_no(nofail));
 580
 581                 if (streq(me->mnt_type, "swap"))
 582                         k = add_swap(what, me,
 583                                      makefs*MAKEFS | growfs*GROWFS | noauto*NOAUTO | nofail*NOFAIL);
 584                 else {
 585                         bool automount;
 586                         const char *post;
 587
 588                         automount = fstab_test_option(me->mnt_opts,
 589                                                       "comment=systemd.automount\0"
 590                                                       "x-systemd.automount\0");
 591                         if (initrd)
 592                                 post = SPECIAL_INITRD_FS_TARGET;
 593                         else if (mount_is_network(me))
 594                                 post = SPECIAL_REMOTE_FS_TARGET;
 595                         else
 596                                 post = SPECIAL_LOCAL_FS_TARGET;
 597
 598                         k = add_mount(arg_dest,
 599                                       what,
 600                                       canonical_where ?: where,
 601                                       canonical_where ? where: NULL,
 602                                       me->mnt_type,
 603                                       me->mnt_opts,
 604                                       me->mnt_passno,
 605                                       makefs*MAKEFS | growfs*GROWFS | noauto*NOAUTO | nofail*NOFAIL | automount*AUTOMOUNT,
 606                                       post,
 607                                       fstab_path);
 608                 }
 609
 610                 if (r >= 0 && k < 0)
 611                         r = k;
 612         }
 613
 614         return r;
 615 }
 616
 617 static int add_sysroot_mount(void) {
 618         _cleanup_free_ char *what = NULL;
 619         const char *opts;
 620         int r;
 621
 622         if (isempty(arg_root_what)) {
 623                 log_debug("Could not find a root= entry on the kernel command line.");
 624                 return 0;
 625         }
 626
 627         if (streq(arg_root_what, "gpt-auto")) {
 628                 /* This is handled by the gpt-auto generator */
 629                 log_debug("Skipping root directory handling, as gpt-auto was requested.");
 630                 return 0;
 631         }
 632
 633         if (path_equal(arg_root_what, "/dev/nfs")) {
 634                 /* This is handled by the kernel or the initrd */
 635                 log_debug("Skipping root directory handling, as /dev/nfs was requested.");
 636                 return 0;
 637         }
 638
 639         what = fstab_node_to_udev_node(arg_root_what);
 640         if (!what)
 641                 return log_oom();
 642
 643         if (!arg_root_options)
 644                 opts = arg_root_rw > 0 ? "rw" : "ro";
 645         else if (arg_root_rw >= 0 ||
 646                  !fstab_test_option(arg_root_options, "ro\0" "rw\0"))
 647                 opts = strjoina(arg_root_options, ",", arg_root_rw > 0 ? "rw" : "ro");
 648         else
 649                 opts = arg_root_options;
 650
 651         log_debug("Found entry what=%s where=/sysroot type=%s", what, strna(arg_root_fstype));
 652
 653         if (is_device_path(what)) {
 654                 r = generator_write_initrd_root_device_deps(arg_dest, what);
 655                 if (r < 0)
 656                         return r;
 657         }
 658
 659         return add_mount(arg_dest,
 660                          what,
 661                          "/sysroot",
 662                          NULL,
 663                          arg_root_fstype,
 664                          opts,
 665                          is_device_path(what) ? 1 : 0, /* passno */
 666                          0,                            /* makefs off, growfs off, noauto off, nofail off, automount off */
 667                          SPECIAL_INITRD_ROOT_FS_TARGET,
 668                          "/proc/cmdline");
 669 }
 670
 671 static int add_sysroot_usr_mount(void) {
 672         _cleanup_free_ char *what = NULL;
 673         const char *opts;
 674
 675         if (!arg_usr_what && !arg_usr_fstype && !arg_usr_options)
 676                 return 0;
 677
 678         if (arg_root_what && !arg_usr_what) {
 679                 /* Copy over the root device, in case the /usr mount just differs in a mount option (consider btrfs subvolumes) */
 680                 arg_usr_what = strdup(arg_root_what);
 681                 if (!arg_usr_what)
 682                         return log_oom();
 683         }
 684
 685         if (arg_root_fstype && !arg_usr_fstype) {
 686                 arg_usr_fstype = strdup(arg_root_fstype);
 687                 if (!arg_usr_fstype)
 688                         return log_oom();
 689         }
 690
 691         if (arg_root_options && !arg_usr_options) {
 692                 arg_usr_options = strdup(arg_root_options);
 693                 if (!arg_usr_options)
 694                         return log_oom();
 695         }
 696
 697         if (!arg_usr_what)
 698                 return 0;
 699
 700         what = fstab_node_to_udev_node(arg_usr_what);
 701         if (!what)
 702                 return log_oom();
 703
 704         if (!arg_usr_options)
 705                 opts = arg_root_rw > 0 ? "rw" : "ro";
 706         else if (!fstab_test_option(arg_usr_options, "ro\0" "rw\0"))
 707                 opts = strjoina(arg_usr_options, ",", arg_root_rw > 0 ? "rw" : "ro");
 708         else
 709                 opts = arg_usr_options;
 710
 711         log_debug("Found entry what=%s where=/sysroot/usr type=%s", what, strna(arg_usr_fstype));
 712         return add_mount(arg_dest,
 713                          what,
 714                          "/sysroot/usr",
 715                          NULL,
 716                          arg_usr_fstype,
 717                          opts,
 718                          is_device_path(what) ? 1 : 0, /* passno */
 719                          0,
 720                          SPECIAL_INITRD_FS_TARGET,
 721                          "/proc/cmdline");
 722 }
 723
 724 static int add_volatile_root(void) {
 725         /* Let's add in systemd-remount-volatile.service which will remount the root device to tmpfs if this is
 726          * requested, leaving only /usr from the root mount inside. */
 727
 728         if (arg_volatile_mode != VOLATILE_YES)
 729                 return 0;
 730
 731         return generator_add_symlink(arg_dest, SPECIAL_INITRD_ROOT_FS_TARGET, "requires",
 732                                      SYSTEM_DATA_UNIT_PATH "/" SPECIAL_VOLATILE_ROOT_SERVICE);
 733 }
 734
 735 static int add_volatile_var(void) {
 736
 737         if (arg_volatile_mode != VOLATILE_STATE)
 738                 return 0;
 739
 740         /* If requested, mount /var as tmpfs, but do so only if there's nothing else defined for this. */
 741
 742         return add_mount(arg_dest_late,
 743                          "tmpfs",
 744                          "/var",
 745                          NULL,
 746                          "tmpfs",
 747                          "mode=0755",
 748                          0,
 749                          0,
 750                          SPECIAL_LOCAL_FS_TARGET,
 751                          "/proc/cmdline");
 752 }
 753
 754 static int parse_proc_cmdline_item(const char *key, const char *value, void *data) {
 755         int r;
 756
 757         /* root=, usr=, usrfstype= and roofstype= may occur more than once, the last
 758          * instance should take precedence.  In the case of multiple rootflags=
 759          * or usrflags= the arguments should be concatenated */
 760
 761         if (STR_IN_SET(key, "fstab", "rd.fstab")) {
 762
 763                 r = value ? parse_boolean(value) : 1;
 764                 if (r < 0)
 765                         log_warning("Failed to parse fstab switch %s. Ignoring.", value);
 766                 else
 767                         arg_fstab_enabled = r;
 768
 769         } else if (streq(key, "root")) {
 770
 771                 if (proc_cmdline_value_missing(key, value))
 772                         return 0;
 773
 774                 if (free_and_strdup(&arg_root_what, value) < 0)
 775                         return log_oom();
 776
 777         } else if (streq(key, "rootfstype")) {
 778
 779                 if (proc_cmdline_value_missing(key, value))
 780                         return 0;
 781
 782                 if (free_and_strdup(&arg_root_fstype, value) < 0)
 783                         return log_oom();
 784
 785         } else if (streq(key, "rootflags")) {
 786
 787                 if (proc_cmdline_value_missing(key, value))
 788                         return 0;
 789
 790                 if (!strextend_with_separator(&arg_root_options, ",", value, NULL))
 791                         return log_oom();
 792
 793         } else if (streq(key, "roothash")) {
 794
 795                 if (proc_cmdline_value_missing(key, value))
 796                         return 0;
 797
 798                 if (free_and_strdup(&arg_root_hash, value) < 0)
 799                         return log_oom();
 800
 801         } else if (streq(key, "mount.usr")) {
 802
 803                 if (proc_cmdline_value_missing(key, value))
 804                         return 0;
 805
 806                 if (free_and_strdup(&arg_usr_what, value) < 0)
 807                         return log_oom();
 808
 809         } else if (streq(key, "mount.usrfstype")) {
 810
 811                 if (proc_cmdline_value_missing(key, value))
 812                         return 0;
 813
 814                 if (free_and_strdup(&arg_usr_fstype, value) < 0)
 815                         return log_oom();
 816
 817         } else if (streq(key, "mount.usrflags")) {
 818
 819                 if (proc_cmdline_value_missing(key, value))
 820                         return 0;
 821
 822                 if (!strextend_with_separator(&arg_usr_options, ",", value, NULL))
 823                         return log_oom();
 824
 825         } else if (streq(key, "rw") && !value)
 826                 arg_root_rw = true;
 827         else if (streq(key, "ro") && !value)
 828                 arg_root_rw = false;
 829         else if (streq(key, "systemd.volatile")) {
 830                 VolatileMode m;
 831
 832                 if (value) {
 833                         m = volatile_mode_from_string(value);
 834                         if (m < 0)
 835                                 log_warning("Failed to parse systemd.volatile= argument: %s", value);
 836                         else
 837                                 arg_volatile_mode = m;
 838                 } else
 839                         arg_volatile_mode = VOLATILE_YES;
 840         }
 841
 842         return 0;
 843 }
 844
 845 static int determine_root(void) {
 846         /* If we have a root hash but no root device then Verity is used, and we use the "root" DM device as root. */
 847
 848         if (arg_root_what)
 849                 return 0;
 850
 851         if (!arg_root_hash)
 852                 return 0;
 853
 854         arg_root_what = strdup("/dev/mapper/root");
 855         if (!arg_root_what)
 856                 return log_oom();
 857
 858         log_info("Using verity root device %s.", arg_root_what);
 859
 860         return 1;
 861 }
 862
 863 static int run(const char *dest, const char *dest_early, const char *dest_late) {
 864         int r, r2 = 0, r3 = 0;
 865
 866         assert_se(arg_dest = dest);
 867         assert_se(arg_dest_late = dest_late);
 868
 869         r = proc_cmdline_parse(parse_proc_cmdline_item, NULL, 0);
 870         if (r < 0)
 871                 log_warning_errno(r, "Failed to parse kernel command line, ignoring: %m");
 872
 873         (void) determine_root();
 874
 875         /* Always honour root= and usr= in the kernel command line if we are in an initrd */
 876         if (in_initrd()) {
 877                 r = add_sysroot_mount();
 878
 879                 r2 = add_sysroot_usr_mount();
 880
 881                 r3 = add_volatile_root();
 882         } else
 883                 r = add_volatile_var();
 884
 885         /* Honour /etc/fstab only when that's enabled */
 886         if (arg_fstab_enabled) {
 887                 /* Parse the local /etc/fstab, possibly from the initrd */
 888                 r2 = parse_fstab(false);
 889
 890                 /* If running in the initrd also parse the /etc/fstab from the host */
 891                 if (in_initrd())
 892                         r3 = parse_fstab(true);
 893                 else
 894                         r3 = generator_enable_remount_fs_service(arg_dest);
 895         }
 896
 897         return r < 0 ? r : r2 < 0 ? r2 : r3;
 898 }
 899
 900 DEFINE_MAIN_GENERATOR_FUNCTION(run);