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 <unistd.h>
   7
   8 #include "alloc-util.h"
   9 #include "fd-util.h"
  10 #include "fileio.h"
  11 #include "fs-util.h"
  12 #include "fstab-util.h"
  13 #include "generator.h"
  14 #include "log.h"
  15 #include "main-func.h"
  16 #include "mkdir.h"
  17 #include "mount-setup.h"
  18 #include "mount-util.h"
  19 #include "mountpoint-util.h"
  20 #include "parse-util.h"
  21 #include "path-util.h"
  22 #include "proc-cmdline.h"
  23 #include "special.h"
  24 #include "specifier.h"
  25 #include "stat-util.h"
  26 #include "string-util.h"
  27 #include "strv.h"
  28 #include "unit-name.h"
  29 #include "util.h"
  30 #include "virt.h"
  31 #include "volatile-util.h"
  32
  33 typedef enum MountpointFlags {
  34         NOAUTO    = 1 << 0,
  35         NOFAIL    = 1 << 1,
  36         AUTOMOUNT = 1 << 2,
  37         MAKEFS    = 1 << 3,
  38         GROWFS    = 1 << 4,
  39 } MountpointFlags;
  40
  41 static const char *arg_dest = NULL;
  42 static const char *arg_dest_late = NULL;
  43 static bool arg_fstab_enabled = true;
  44 static char *arg_root_what = NULL;
  45 static char *arg_root_fstype = NULL;
  46 static char *arg_root_options = NULL;
  47 static char *arg_root_hash = NULL;
  48 static int arg_root_rw = -1;
  49 static char *arg_usr_what = NULL;
  50 static char *arg_usr_fstype = NULL;
  51 static char *arg_usr_options = NULL;
  52 static VolatileMode arg_volatile_mode = _VOLATILE_MODE_INVALID;
  53
  54 STATIC_DESTRUCTOR_REGISTER(arg_root_what, freep);
  55 STATIC_DESTRUCTOR_REGISTER(arg_root_fstype, freep);
  56 STATIC_DESTRUCTOR_REGISTER(arg_root_options, freep);
  57 STATIC_DESTRUCTOR_REGISTER(arg_root_hash, freep);
  58 STATIC_DESTRUCTOR_REGISTER(arg_usr_what, freep);
  59 STATIC_DESTRUCTOR_REGISTER(arg_usr_fstype, freep);
  60 STATIC_DESTRUCTOR_REGISTER(arg_usr_options, freep);
  61
  62 static int write_options(FILE *f, const char *options) {
  63         _cleanup_free_ char *o = NULL;
  64
  65         if (isempty(options))
  66                 return 0;
  67
  68         if (streq(options, "defaults"))
  69                 return 0;
  70
  71         o = specifier_escape(options);
  72         if (!o)
  73                 return log_oom();
  74
  75         fprintf(f, "Options=%s\n", o);
  76         return 1;
  77 }
  78
  79 static int write_what(FILE *f, const char *what) {
  80         _cleanup_free_ char *w = NULL;
  81
  82         w = specifier_escape(what);
  83         if (!w)
  84                 return log_oom();
  85
  86         fprintf(f, "What=%s\n", w);
  87         return 1;
  88 }
  89
  90 static int add_swap(
  91                 const char *what,
  92                 struct mntent *me,
  93                 MountpointFlags flags) {
  94
  95         _cleanup_free_ char *name = NULL;
  96         _cleanup_fclose_ FILE *f = NULL;
  97         int r;
  98
  99         assert(what);
 100         assert(me);
 101
 102         if (access("/proc/swaps", F_OK) < 0) {
 103                 log_info("Swap not supported, ignoring fstab swap entry for %s.", what);
 104                 return 0;
 105         }
 106
 107         if (detect_container() > 0) {
 108                 log_info("Running in a container, ignoring fstab swap entry for %s.", what);
 109                 return 0;
 110         }
 111
 112         r = unit_name_from_path(what, ".swap", &name);
 113         if (r < 0)
 114                 return log_error_errno(r, "Failed to generate unit name: %m");
 115
 116         r = generator_open_unit_file(arg_dest, "/etc/fstab", name, &f);
 117         if (r < 0)
 118                 return r;
 119
 120         fputs("[Unit]\n"
 121               "SourcePath=/etc/fstab\n"
 122               "Documentation=man:fstab(5) man:systemd-fstab-generator(8)\n\n"
 123               "[Swap]\n", f);
 124
 125         r = write_what(f, what);
 126         if (r < 0)
 127                 return r;
 128
 129         r = write_options(f, me->mnt_opts);
 130         if (r < 0)
 131                 return r;
 132
 133         r = fflush_and_check(f);
 134         if (r < 0)
 135                 return log_error_errno(r, "Failed to write unit file %s: %m", name);
 136
 137         /* use what as where, to have a nicer error message */
 138         r = generator_write_timeouts(arg_dest, what, what, me->mnt_opts, NULL);
 139         if (r < 0)
 140                 return r;
 141
 142         if (flags & MAKEFS) {
 143                 r = generator_hook_up_mkswap(arg_dest, what);
 144                 if (r < 0)
 145                         return r;
 146         }
 147
 148         if (flags & GROWFS)
 149                 /* TODO: swap devices must be wiped and recreated */
 150                 log_warning("%s: growing swap devices is currently unsupported.", what);
 151
 152         if (!(flags & NOAUTO)) {
 153                 r = generator_add_symlink(arg_dest, SPECIAL_SWAP_TARGET,
 154                                           (flags & NOFAIL) ? "wants" : "requires", name);
 155                 if (r < 0)
 156                         return r;
 157         }
 158
 159         return 0;
 160 }
 161
 162 static bool mount_is_network(struct mntent *me) {
 163         assert(me);
 164
 165         return fstab_test_option(me->mnt_opts, "_netdev\0") ||
 166                fstype_is_network(me->mnt_type);
 167 }
 168
 169 static bool mount_in_initrd(struct mntent *me) {
 170         assert(me);
 171
 172         return fstab_test_option(me->mnt_opts, "x-initrd.mount\0") ||
 173                streq(me->mnt_dir, "/usr");
 174 }
 175
 176 static int write_timeout(FILE *f, const char *where, const char *opts,
 177                          const char *filter, const char *variable) {
 178         _cleanup_free_ char *timeout = NULL;
 179         char timespan[FORMAT_TIMESPAN_MAX];
 180         usec_t u;
 181         int r;
 182
 183         r = fstab_filter_options(opts, filter, NULL, &timeout, NULL);
 184         if (r < 0)
 185                 return log_warning_errno(r, "Failed to parse options: %m");
 186         if (r == 0)
 187                 return 0;
 188
 189         r = parse_sec_fix_0(timeout, &u);
 190         if (r < 0) {
 191                 log_warning("Failed to parse timeout for %s, ignoring: %s", where, timeout);
 192                 return 0;
 193         }
 194
 195         fprintf(f, "%s=%s\n", variable, format_timespan(timespan, sizeof(timespan), u, 0));
 196
 197         return 0;
 198 }
 199
 200 static int write_idle_timeout(FILE *f, const char *where, const char *opts) {
 201         return write_timeout(f, where, opts,
 202                              "x-systemd.idle-timeout\0", "TimeoutIdleSec");
 203 }
 204
 205 static int write_mount_timeout(FILE *f, const char *where, const char *opts) {
 206         return write_timeout(f, where, opts,
 207                              "x-systemd.mount-timeout\0", "TimeoutSec");
 208 }
 209
 210 static int write_dependency(FILE *f, const char *opts,
 211                 const char *filter, const char *format) {
 212         _cleanup_strv_free_ char **names = NULL, **units = NULL;
 213         _cleanup_free_ char *res = NULL;
 214         char **s;
 215         int r;
 216
 217         assert(f);
 218         assert(opts);
 219
 220         r = fstab_extract_values(opts, filter, &names);
 221         if (r < 0)
 222                 return log_warning_errno(r, "Failed to parse options: %m");
 223         if (r == 0)
 224                 return 0;
 225
 226         STRV_FOREACH(s, names) {
 227                 char *x;
 228
 229                 r = unit_name_mangle_with_suffix(*s, "as dependency", 0, ".mount", &x);
 230                 if (r < 0)
 231                         return log_error_errno(r, "Failed to generate unit name: %m");
 232                 r = strv_consume(&units, x);
 233                 if (r < 0)
 234                         return log_oom();
 235         }
 236
 237         if (units) {
 238                 res = strv_join(units, " ");
 239                 if (!res)
 240                         return log_oom();
 241 #pragma GCC diagnostic push
 242 #pragma GCC diagnostic ignored "-Wformat-nonliteral"
 243                 fprintf(f, format, res);
 244 #pragma GCC diagnostic pop
 245         }
 246
 247         return 0;
 248 }
 249
 250 static int write_after(FILE *f, const char *opts) {
 251         return write_dependency(f, opts, "x-systemd.after", "After=%1$s\n");
 252 }
 253
 254 static int write_requires_after(FILE *f, const char *opts) {
 255         return write_dependency(f, opts,
 256                                 "x-systemd.requires", "After=%1$s\nRequires=%1$s\n");
 257 }
 258
 259 static int write_before(FILE *f, const char *opts) {
 260         return write_dependency(f, opts,
 261                                 "x-systemd.before", "Before=%1$s\n");
 262 }
 263
 264 static int write_requires_mounts_for(FILE *f, const char *opts) {
 265         _cleanup_strv_free_ char **paths = NULL, **paths_escaped = NULL;
 266         _cleanup_free_ char *res = NULL;
 267         int r;
 268
 269         assert(f);
 270         assert(opts);
 271
 272         r = fstab_extract_values(opts, "x-systemd.requires-mounts-for", &paths);
 273         if (r < 0)
 274                 return log_warning_errno(r, "Failed to parse options: %m");
 275         if (r == 0)
 276                 return 0;
 277
 278         r = specifier_escape_strv(paths, &paths_escaped);
 279         if (r < 0)
 280                 return log_error_errno(r, "Failed to escape paths: %m");
 281
 282         res = strv_join(paths_escaped, " ");
 283         if (!res)
 284                 return log_oom();
 285
 286         fprintf(f, "RequiresMountsFor=%s\n", res);
 287
 288         return 0;
 289 }
 290
 291 static int add_mount(
 292                 const char *dest,
 293                 const char *what,
 294                 const char *where,
 295                 const char *original_where,
 296                 const char *fstype,
 297                 const char *opts,
 298                 int passno,
 299                 MountpointFlags flags,
 300                 const char *post,
 301                 const char *source) {
 302
 303         _cleanup_free_ char
 304                 *name = NULL,
 305                 *automount_name = NULL,
 306                 *filtered = NULL,
 307                 *where_escaped = NULL;
 308         _cleanup_fclose_ FILE *f = NULL;
 309         int r;
 310
 311         assert(what);
 312         assert(where);
 313         assert(opts);
 314         assert(post);
 315         assert(source);
 316
 317         if (streq_ptr(fstype, "autofs"))
 318                 return 0;
 319
 320         if (!is_path(where)) {
 321                 log_warning("Mount point %s is not a valid path, ignoring.", where);
 322                 return 0;
 323         }
 324
 325         if (mount_point_is_api(where) ||
 326             mount_point_ignore(where))
 327                 return 0;
 328
 329         if (path_equal(where, "/")) {
 330                 if (flags & NOAUTO)
 331                         log_warning("Ignoring \"noauto\" for root device");
 332                 if (flags & NOFAIL)
 333                         log_warning("Ignoring \"nofail\" for root device");
 334                 if (flags & AUTOMOUNT)
 335                         log_warning("Ignoring automount option for root device");
 336
 337                 SET_FLAG(flags, NOAUTO | NOFAIL | AUTOMOUNT, false);
 338         }
 339
 340         r = unit_name_from_path(where, ".mount", &name);
 341         if (r < 0)
 342                 return log_error_errno(r, "Failed to generate unit name: %m");
 343
 344         r = generator_open_unit_file(dest, "/etc/fstab", name, &f);
 345         if (r < 0)
 346                 return r;
 347
 348         fprintf(f,
 349                 "[Unit]\n"
 350                 "SourcePath=%s\n"
 351                 "Documentation=man:fstab(5) man:systemd-fstab-generator(8)\n",
 352                 source);
 353
 354         /* All mounts under /sysroot need to happen later, at initrd-fs.target time. IOW, it's not
 355          * technically part of the basic initrd filesystem itself, and so shouldn't inherit the default
 356          * Before=local-fs.target dependency. */
 357         if (in_initrd() && path_startswith(where, "/sysroot"))
 358                 fprintf(f, "DefaultDependencies=no\n");
 359
 360         if (STRPTR_IN_SET(fstype, "nfs", "nfs4") && !(flags & AUTOMOUNT) &&
 361             fstab_test_yes_no_option(opts, "bg\0" "fg\0")) {
 362                 /* The default retry timeout that mount.nfs uses for 'bg' mounts
 363                  * is 10000 minutes, where as it uses 2 minutes for 'fg' mounts.
 364                  * As we are making  'bg' mounts look like an 'fg' mount to
 365                  * mount.nfs (so systemd can manage the job-control aspects of 'bg'),
 366                  * we need to explicitly preserve that default, and also ensure
 367                  * the systemd mount-timeout doesn't interfere.
 368                  * By placing these options first, they can be over-ridden by
 369                  * settings in /etc/fstab. */
 370                 opts = strjoina("x-systemd.mount-timeout=infinity,retry=10000,", opts, ",fg");
 371                 SET_FLAG(flags, NOFAIL, true);
 372         }
 373
 374         if (!(flags & NOFAIL) && !(flags & AUTOMOUNT))
 375                 fprintf(f, "Before=%s\n", post);
 376
 377         if (!(flags & AUTOMOUNT) && opts) {
 378                  r = write_after(f, opts);
 379                  if (r < 0)
 380                          return r;
 381                  r = write_requires_after(f, opts);
 382                  if (r < 0)
 383                          return r;
 384                  r = write_before(f, opts);
 385                  if (r < 0)
 386                          return r;
 387                  r = write_requires_mounts_for(f, opts);
 388                  if (r < 0)
 389                          return r;
 390         }
 391
 392         if (passno != 0) {
 393                 r = generator_write_fsck_deps(f, dest, what, where, fstype);
 394                 if (r < 0)
 395                         return r;
 396         }
 397
 398         fprintf(f, "\n[Mount]\n");
 399         if (original_where)
 400                 fprintf(f, "# Canonicalized from %s\n", original_where);
 401
 402         where_escaped = specifier_escape(where);
 403         if (!where_escaped)
 404                 return log_oom();
 405         fprintf(f, "Where=%s\n", where_escaped);
 406
 407         r = write_what(f, what);
 408         if (r < 0)
 409                 return r;
 410
 411         if (!isempty(fstype) && !streq(fstype, "auto")) {
 412                 _cleanup_free_ char *t;
 413
 414                 t = specifier_escape(fstype);
 415                 if (!t)
 416                         return -ENOMEM;
 417
 418                 fprintf(f, "Type=%s\n", t);
 419         }
 420
 421         r = generator_write_timeouts(dest, what, where, opts, &filtered);
 422         if (r < 0)
 423                 return r;
 424
 425         r = generator_write_device_deps(dest, what, where, opts);
 426         if (r < 0)
 427                 return r;
 428
 429         r = write_mount_timeout(f, where, opts);
 430         if (r < 0)
 431                 return r;
 432
 433         r = write_options(f, filtered);
 434         if (r < 0)
 435                 return r;
 436
 437         r = fflush_and_check(f);
 438         if (r < 0)
 439                 return log_error_errno(r, "Failed to write unit file %s: %m", name);
 440
 441         if (flags & MAKEFS) {
 442                 r = generator_hook_up_mkfs(dest, what, where, fstype);
 443                 if (r < 0)
 444                         return r;
 445         }
 446
 447         if (flags & GROWFS) {
 448                 r = generator_hook_up_growfs(dest, where, post);
 449                 if (r < 0)
 450                         return r;
 451         }
 452
 453         if (!(flags & NOAUTO) && !(flags & AUTOMOUNT)) {
 454                 r = generator_add_symlink(dest, post,
 455                                           (flags & NOFAIL) ? "wants" : "requires", name);
 456                 if (r < 0)
 457                         return r;
 458         }
 459
 460         if (flags & AUTOMOUNT) {
 461                 r = unit_name_from_path(where, ".automount", &automount_name);
 462                 if (r < 0)
 463                         return log_error_errno(r, "Failed to generate unit name: %m");
 464
 465                 f = safe_fclose(f);
 466
 467                 r = generator_open_unit_file(dest, "/etc/fstab", automount_name, &f);
 468                 if (r < 0)
 469                         return r;
 470
 471                 fprintf(f,
 472                         "[Unit]\n"
 473                         "SourcePath=%s\n"
 474                         "Documentation=man:fstab(5) man:systemd-fstab-generator(8)\n",
 475                         source);
 476
 477                 fprintf(f, "Before=%s\n", post);
 478
 479                 if (opts) {
 480                         r = write_after(f, opts);
 481                         if (r < 0)
 482                                 return r;
 483                         r = write_requires_after(f, opts);
 484                         if (r < 0)
 485                                 return r;
 486                         r = write_before(f, opts);
 487                         if (r < 0)
 488                                 return r;
 489                         r = write_requires_mounts_for(f, opts);
 490                         if (r < 0)
 491                                 return r;
 492                 }
 493
 494                 fprintf(f,
 495                         "\n"
 496                         "[Automount]\n"
 497                         "Where=%s\n",
 498                         where_escaped);
 499
 500                 r = write_idle_timeout(f, where, opts);
 501                 if (r < 0)
 502                         return r;
 503
 504                 r = fflush_and_check(f);
 505                 if (r < 0)
 506                         return log_error_errno(r, "Failed to write unit file %s: %m", automount_name);
 507
 508                 r = generator_add_symlink(dest, post,
 509                                           (flags & NOFAIL) ? "wants" : "requires", automount_name);
 510                 if (r < 0)
 511                         return r;
 512         }
 513
 514         return 0;
 515 }
 516
 517 static int parse_fstab(bool initrd) {
 518         _cleanup_endmntent_ FILE *f = NULL;
 519         const char *fstab_path;
 520         struct mntent *me;
 521         int r = 0;
 522
 523         fstab_path = initrd ? "/sysroot/etc/fstab" : "/etc/fstab";
 524         log_debug("Parsing %s...", fstab_path);
 525
 526         f = setmntent(fstab_path, "re");
 527         if (!f) {
 528                 if (errno == ENOENT)
 529                         return 0;
 530
 531                 return log_error_errno(errno, "Failed to open %s: %m", fstab_path);
 532         }
 533
 534         while ((me = getmntent(f))) {
 535                 _cleanup_free_ char *where = NULL, *what = NULL, *canonical_where = NULL;
 536                 bool makefs, growfs, noauto, nofail;
 537                 int k;
 538
 539                 if (initrd && !mount_in_initrd(me))
 540                         continue;
 541
 542                 what = fstab_node_to_udev_node(me->mnt_fsname);
 543                 if (!what)
 544                         return log_oom();
 545
 546                 if (is_device_path(what) && path_is_read_only_fs("/sys") > 0) {
 547                         log_info("Running in a container, ignoring fstab device entry for %s.", what);
 548                         continue;
 549                 }
 550
 551                 where = strdup(me->mnt_dir);
 552                 if (!where)
 553                         return log_oom();
 554
 555                 if (is_path(where)) {
 556                         path_simplify(where, false);
 557
 558                         /* Follow symlinks here; see 5261ba901845c084de5a8fd06500ed09bfb0bd80 which makes sense for
 559                          * mount units, but causes problems since it historically worked to have symlinks in e.g.
 560                          * /etc/fstab. So we canonicalize here. Note that we use CHASE_NONEXISTENT to handle the case
 561                          * where a symlink refers to another mount target; this works assuming the sub-mountpoint
 562                          * target is the final directory. */
 563                         r = chase_symlinks(where, initrd ? "/sysroot" : NULL,
 564                                            CHASE_PREFIX_ROOT | CHASE_NONEXISTENT,
 565                                            &canonical_where, NULL);
 566                         if (r < 0) /* If we can't canonicalize we continue on as if it wasn't a symlink */
 567                                 log_debug_errno(r, "Failed to read symlink target for %s, ignoring: %m", where);
 568                         else if (streq(canonical_where, where)) /* If it was fully canonicalized, suppress the change */
 569                                 canonical_where = mfree(canonical_where);
 570                         else
 571                                 log_debug("Canonicalized what=%s where=%s to %s", what, where, canonical_where);
 572                 }
 573
 574                 makefs = fstab_test_option(me->mnt_opts, "x-systemd.makefs\0");
 575                 growfs = fstab_test_option(me->mnt_opts, "x-systemd.growfs\0");
 576                 noauto = fstab_test_yes_no_option(me->mnt_opts, "noauto\0" "auto\0");
 577                 nofail = fstab_test_yes_no_option(me->mnt_opts, "nofail\0" "fail\0");
 578
 579                 log_debug("Found entry what=%s where=%s type=%s makefs=%s growfs=%s noauto=%s nofail=%s",
 580                           what, where, me->mnt_type,
 581                           yes_no(makefs), yes_no(growfs),
 582                           yes_no(noauto), yes_no(nofail));
 583
 584                 if (streq(me->mnt_type, "swap"))
 585                         k = add_swap(what, me,
 586                                      makefs*MAKEFS | growfs*GROWFS | noauto*NOAUTO | nofail*NOFAIL);
 587                 else {
 588                         bool automount;
 589                         const char *post;
 590
 591                         automount = fstab_test_option(me->mnt_opts,
 592                                                       "comment=systemd.automount\0"
 593                                                       "x-systemd.automount\0");
 594                         if (initrd)
 595                                 post = SPECIAL_INITRD_FS_TARGET;
 596                         else if (mount_is_network(me))
 597                                 post = SPECIAL_REMOTE_FS_TARGET;
 598                         else
 599                                 post = SPECIAL_LOCAL_FS_TARGET;
 600
 601                         k = add_mount(arg_dest,
 602                                       what,
 603                                       canonical_where ?: where,
 604                                       canonical_where ? where: NULL,
 605                                       me->mnt_type,
 606                                       me->mnt_opts,
 607                                       me->mnt_passno,
 608                                       makefs*MAKEFS | growfs*GROWFS | noauto*NOAUTO | nofail*NOFAIL | automount*AUTOMOUNT,
 609                                       post,
 610                                       fstab_path);
 611                 }
 612
 613                 if (r >= 0 && k < 0)
 614                         r = k;
 615         }
 616
 617         return r;
 618 }
 619
 620 static int add_sysroot_mount(void) {
 621         _cleanup_free_ char *what = NULL;
 622         const char *opts;
 623         int r;
 624
 625         if (isempty(arg_root_what)) {
 626                 log_debug("Could not find a root= entry on the kernel command line.");
 627                 return 0;
 628         }
 629
 630         if (streq(arg_root_what, "gpt-auto")) {
 631                 /* This is handled by the gpt-auto generator */
 632                 log_debug("Skipping root directory handling, as gpt-auto was requested.");
 633                 return 0;
 634         }
 635
 636         if (path_equal(arg_root_what, "/dev/nfs")) {
 637                 /* This is handled by the kernel or the initrd */
 638                 log_debug("Skipping root directory handling, as /dev/nfs was requested.");
 639                 return 0;
 640         }
 641
 642         what = fstab_node_to_udev_node(arg_root_what);
 643         if (!what)
 644                 return log_oom();
 645
 646         if (!arg_root_options)
 647                 opts = arg_root_rw > 0 ? "rw" : "ro";
 648         else if (arg_root_rw >= 0 ||
 649                  !fstab_test_option(arg_root_options, "ro\0" "rw\0"))
 650                 opts = strjoina(arg_root_options, ",", arg_root_rw > 0 ? "rw" : "ro");
 651         else
 652                 opts = arg_root_options;
 653
 654         log_debug("Found entry what=%s where=/sysroot type=%s", what, strna(arg_root_fstype));
 655
 656         if (is_device_path(what)) {
 657                 r = generator_write_initrd_root_device_deps(arg_dest, what);
 658                 if (r < 0)
 659                         return r;
 660         }
 661
 662         return add_mount(arg_dest,
 663                          what,
 664                          "/sysroot",
 665                          NULL,
 666                          arg_root_fstype,
 667                          opts,
 668                          is_device_path(what) ? 1 : 0, /* passno */
 669                          0,                            /* makefs off, growfs off, noauto off, nofail off, automount off */
 670                          SPECIAL_INITRD_ROOT_FS_TARGET,
 671                          "/proc/cmdline");
 672 }
 673
 674 static int add_sysroot_usr_mount(void) {
 675         _cleanup_free_ char *what = NULL;
 676         const char *opts;
 677
 678         if (!arg_usr_what && !arg_usr_fstype && !arg_usr_options)
 679                 return 0;
 680
 681         if (arg_root_what && !arg_usr_what) {
 682                 /* Copy over the root device, in case the /usr mount just differs in a mount option (consider btrfs subvolumes) */
 683                 arg_usr_what = strdup(arg_root_what);
 684                 if (!arg_usr_what)
 685                         return log_oom();
 686         }
 687
 688         if (arg_root_fstype && !arg_usr_fstype) {
 689                 arg_usr_fstype = strdup(arg_root_fstype);
 690                 if (!arg_usr_fstype)
 691                         return log_oom();
 692         }
 693
 694         if (arg_root_options && !arg_usr_options) {
 695                 arg_usr_options = strdup(arg_root_options);
 696                 if (!arg_usr_options)
 697                         return log_oom();
 698         }
 699
 700         if (!arg_usr_what)
 701                 return 0;
 702
 703         what = fstab_node_to_udev_node(arg_usr_what);
 704         if (!what)
 705                 return log_oom();
 706
 707         if (!arg_usr_options)
 708                 opts = arg_root_rw > 0 ? "rw" : "ro";
 709         else if (!fstab_test_option(arg_usr_options, "ro\0" "rw\0"))
 710                 opts = strjoina(arg_usr_options, ",", arg_root_rw > 0 ? "rw" : "ro");
 711         else
 712                 opts = arg_usr_options;
 713
 714         log_debug("Found entry what=%s where=/sysroot/usr type=%s", what, strna(arg_usr_fstype));
 715         return add_mount(arg_dest,
 716                          what,
 717                          "/sysroot/usr",
 718                          NULL,
 719                          arg_usr_fstype,
 720                          opts,
 721                          is_device_path(what) ? 1 : 0, /* passno */
 722                          0,
 723                          SPECIAL_INITRD_FS_TARGET,
 724                          "/proc/cmdline");
 725 }
 726
 727 static int add_volatile_root(void) {
 728
 729         /* Let's add in systemd-remount-volatile.service which will remount the root device to tmpfs if this is
 730          * requested (or as an overlayfs), leaving only /usr from the root mount inside. */
 731
 732         if (!IN_SET(arg_volatile_mode, VOLATILE_YES, VOLATILE_OVERLAY))
 733                 return 0;
 734
 735         return generator_add_symlink(arg_dest, SPECIAL_INITRD_ROOT_FS_TARGET, "requires",
 736                                      SYSTEM_DATA_UNIT_PATH "/" SPECIAL_VOLATILE_ROOT_SERVICE);
 737 }
 738
 739 static int add_volatile_var(void) {
 740
 741         if (arg_volatile_mode != VOLATILE_STATE)
 742                 return 0;
 743
 744         /* If requested, mount /var as tmpfs, but do so only if there's nothing else defined for this. */
 745
 746         return add_mount(arg_dest_late,
 747                          "tmpfs",
 748                          "/var",
 749                          NULL,
 750                          "tmpfs",
 751                          "mode=0755",
 752                          0,
 753                          0,
 754                          SPECIAL_LOCAL_FS_TARGET,
 755                          "/proc/cmdline");
 756 }
 757
 758 static int parse_proc_cmdline_item(const char *key, const char *value, void *data) {
 759         int r;
 760
 761         /* root=, usr=, usrfstype= and roofstype= may occur more than once, the last
 762          * instance should take precedence.  In the case of multiple rootflags=
 763          * or usrflags= the arguments should be concatenated */
 764
 765         if (STR_IN_SET(key, "fstab", "rd.fstab")) {
 766
 767                 r = value ? parse_boolean(value) : 1;
 768                 if (r < 0)
 769                         log_warning("Failed to parse fstab switch %s. Ignoring.", value);
 770                 else
 771                         arg_fstab_enabled = r;
 772
 773         } else if (streq(key, "root")) {
 774
 775                 if (proc_cmdline_value_missing(key, value))
 776                         return 0;
 777
 778                 if (free_and_strdup(&arg_root_what, value) < 0)
 779                         return log_oom();
 780
 781         } else if (streq(key, "rootfstype")) {
 782
 783                 if (proc_cmdline_value_missing(key, value))
 784                         return 0;
 785
 786                 if (free_and_strdup(&arg_root_fstype, value) < 0)
 787                         return log_oom();
 788
 789         } else if (streq(key, "rootflags")) {
 790
 791                 if (proc_cmdline_value_missing(key, value))
 792                         return 0;
 793
 794                 if (!strextend_with_separator(&arg_root_options, ",", value, NULL))
 795                         return log_oom();
 796
 797         } else if (streq(key, "roothash")) {
 798
 799                 if (proc_cmdline_value_missing(key, value))
 800                         return 0;
 801
 802                 if (free_and_strdup(&arg_root_hash, value) < 0)
 803                         return log_oom();
 804
 805         } else if (streq(key, "mount.usr")) {
 806
 807                 if (proc_cmdline_value_missing(key, value))
 808                         return 0;
 809
 810                 if (free_and_strdup(&arg_usr_what, value) < 0)
 811                         return log_oom();
 812
 813         } else if (streq(key, "mount.usrfstype")) {
 814
 815                 if (proc_cmdline_value_missing(key, value))
 816                         return 0;
 817
 818                 if (free_and_strdup(&arg_usr_fstype, value) < 0)
 819                         return log_oom();
 820
 821         } else if (streq(key, "mount.usrflags")) {
 822
 823                 if (proc_cmdline_value_missing(key, value))
 824                         return 0;
 825
 826                 if (!strextend_with_separator(&arg_usr_options, ",", value, NULL))
 827                         return log_oom();
 828
 829         } else if (streq(key, "rw") && !value)
 830                 arg_root_rw = true;
 831         else if (streq(key, "ro") && !value)
 832                 arg_root_rw = false;
 833         else if (streq(key, "systemd.volatile")) {
 834                 VolatileMode m;
 835
 836                 if (value) {
 837                         m = volatile_mode_from_string(value);
 838                         if (m < 0)
 839                                 log_warning("Failed to parse systemd.volatile= argument: %s", value);
 840                         else
 841                                 arg_volatile_mode = m;
 842                 } else
 843                         arg_volatile_mode = VOLATILE_YES;
 844         }
 845
 846         return 0;
 847 }
 848
 849 static int determine_root(void) {
 850         /* If we have a root hash but no root device then Verity is used, and we use the "root" DM device as root. */
 851
 852         if (arg_root_what)
 853                 return 0;
 854
 855         if (!arg_root_hash)
 856                 return 0;
 857
 858         arg_root_what = strdup("/dev/mapper/root");
 859         if (!arg_root_what)
 860                 return log_oom();
 861
 862         log_info("Using verity root device %s.", arg_root_what);
 863
 864         return 1;
 865 }
 866
 867 static int run(const char *dest, const char *dest_early, const char *dest_late) {
 868         int r, r2 = 0, r3 = 0;
 869
 870         assert_se(arg_dest = dest);
 871         assert_se(arg_dest_late = dest_late);
 872
 873         r = proc_cmdline_parse(parse_proc_cmdline_item, NULL, 0);
 874         if (r < 0)
 875                 log_warning_errno(r, "Failed to parse kernel command line, ignoring: %m");
 876
 877         (void) determine_root();
 878
 879         /* Always honour root= and usr= in the kernel command line if we are in an initrd */
 880         if (in_initrd()) {
 881                 r = add_sysroot_mount();
 882
 883                 r2 = add_sysroot_usr_mount();
 884
 885                 r3 = add_volatile_root();
 886         } else
 887                 r = add_volatile_var();
 888
 889         /* Honour /etc/fstab only when that's enabled */
 890         if (arg_fstab_enabled) {
 891                 /* Parse the local /etc/fstab, possibly from the initrd */
 892                 r2 = parse_fstab(false);
 893
 894                 /* If running in the initrd also parse the /etc/fstab from the host */
 895                 if (in_initrd())
 896                         r3 = parse_fstab(true);
 897                 else
 898                         r3 = generator_enable_remount_fs_service(arg_dest);
 899         }
 900
 901         return r < 0 ? r : r2 < 0 ? r2 : r3;
 902 }
 903
 904 DEFINE_MAIN_GENERATOR_FUNCTION(run);