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 "mkdir.h"
  18 #include "mount-setup.h"
  19 #include "mount-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 = "/tmp";
  42 static const char *arg_dest_late = "/tmp";
  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 int write_options(FILE *f, const char *options) {
  55         _cleanup_free_ char *o = NULL;
  56
  57         if (isempty(options))
  58                 return 0;
  59
  60         if (streq(options, "defaults"))
  61                 return 0;
  62
  63         o = specifier_escape(options);
  64         if (!o)
  65                 return log_oom();
  66
  67         fprintf(f, "Options=%s\n", o);
  68         return 1;
  69 }
  70
  71 static int write_what(FILE *f, const char *what) {
  72         _cleanup_free_ char *w = NULL;
  73
  74         w = specifier_escape(what);
  75         if (!w)
  76                 return log_oom();
  77
  78         fprintf(f, "What=%s\n", w);
  79         return 1;
  80 }
  81
  82 static int add_swap(
  83                 const char *what,
  84                 struct mntent *me,
  85                 MountpointFlags flags) {
  86
  87         _cleanup_free_ char *name = NULL;
  88         _cleanup_fclose_ FILE *f = NULL;
  89         int r;
  90
  91         assert(what);
  92         assert(me);
  93
  94         if (access("/proc/swaps", F_OK) < 0) {
  95                 log_info("Swap not supported, ignoring fstab swap entry for %s.", what);
  96                 return 0;
  97         }
  98
  99         if (detect_container() > 0) {
 100                 log_info("Running in a container, ignoring fstab swap entry for %s.", what);
 101                 return 0;
 102         }
 103
 104         r = unit_name_from_path(what, ".swap", &name);
 105         if (r < 0)
 106                 return log_error_errno(r, "Failed to generate unit name: %m");
 107
 108         r = generator_open_unit_file(arg_dest, "/etc/fstab", name, &f);
 109         if (r < 0)
 110                 return r;
 111
 112         fputs("# Automatically generated by systemd-fstab-generator\n\n"
 113               "[Unit]\n"
 114               "SourcePath=/etc/fstab\n"
 115               "Documentation=man:fstab(5) man:systemd-fstab-generator(8)\n\n"
 116               "[Swap]\n", f);
 117
 118         r = write_what(f, what);
 119         if (r < 0)
 120                 return r;
 121
 122         r = write_options(f, me->mnt_opts);
 123         if (r < 0)
 124                 return r;
 125
 126         r = fflush_and_check(f);
 127         if (r < 0)
 128                 return log_error_errno(r, "Failed to write unit file %s: %m", name);
 129
 130         /* use what as where, to have a nicer error message */
 131         r = generator_write_timeouts(arg_dest, what, what, me->mnt_opts, NULL);
 132         if (r < 0)
 133                 return r;
 134
 135         if (flags & MAKEFS) {
 136                 r = generator_hook_up_mkswap(arg_dest, what);
 137                 if (r < 0)
 138                         return r;
 139         }
 140
 141         if (flags & GROWFS)
 142                 /* TODO: swap devices must be wiped and recreated */
 143                 log_warning("%s: growing swap devices is currently unsupported.", what);
 144
 145         if (!(flags & NOAUTO)) {
 146                 r = generator_add_symlink(arg_dest, SPECIAL_SWAP_TARGET,
 147                                           (flags & NOFAIL) ? "wants" : "requires", name);
 148                 if (r < 0)
 149                         return r;
 150         }
 151
 152         return 0;
 153 }
 154
 155 static bool mount_is_network(struct mntent *me) {
 156         assert(me);
 157
 158         return fstab_test_option(me->mnt_opts, "_netdev\0") ||
 159                fstype_is_network(me->mnt_type);
 160 }
 161
 162 static bool mount_in_initrd(struct mntent *me) {
 163         assert(me);
 164
 165         return fstab_test_option(me->mnt_opts, "x-initrd.mount\0") ||
 166                streq(me->mnt_dir, "/usr");
 167 }
 168
 169 static int write_timeout(FILE *f, const char *where, const char *opts,
 170                          const char *filter, const char *variable) {
 171         _cleanup_free_ char *timeout = NULL;
 172         char timespan[FORMAT_TIMESPAN_MAX];
 173         usec_t u;
 174         int r;
 175
 176         r = fstab_filter_options(opts, filter, NULL, &timeout, NULL);
 177         if (r < 0)
 178                 return log_warning_errno(r, "Failed to parse options: %m");
 179         if (r == 0)
 180                 return 0;
 181
 182         r = parse_sec_fix_0(timeout, &u);
 183         if (r < 0) {
 184                 log_warning("Failed to parse timeout for %s, ignoring: %s", where, timeout);
 185                 return 0;
 186         }
 187
 188         fprintf(f, "%s=%s\n", variable, format_timespan(timespan, sizeof(timespan), u, 0));
 189
 190         return 0;
 191 }
 192
 193 static int write_idle_timeout(FILE *f, const char *where, const char *opts) {
 194         return write_timeout(f, where, opts,
 195                              "x-systemd.idle-timeout\0", "TimeoutIdleSec");
 196 }
 197
 198 static int write_mount_timeout(FILE *f, const char *where, const char *opts) {
 199         return write_timeout(f, where, opts,
 200                              "x-systemd.mount-timeout\0", "TimeoutSec");
 201 }
 202
 203 static int write_dependency(FILE *f, const char *opts,
 204                 const char *filter, const char *format) {
 205         _cleanup_strv_free_ char **names = NULL, **units = NULL;
 206         _cleanup_free_ char *res = NULL;
 207         char **s;
 208         int r;
 209
 210         assert(f);
 211         assert(opts);
 212
 213         r = fstab_extract_values(opts, filter, &names);
 214         if (r < 0)
 215                 return log_warning_errno(r, "Failed to parse options: %m");
 216         if (r == 0)
 217                 return 0;
 218
 219         STRV_FOREACH(s, names) {
 220                 char *x;
 221
 222                 r = unit_name_mangle_with_suffix(*s, 0, ".mount", &x);
 223                 if (r < 0)
 224                         return log_error_errno(r, "Failed to generate unit name: %m");
 225                 r = strv_consume(&units, x);
 226                 if (r < 0)
 227                         return log_oom();
 228         }
 229
 230         if (units) {
 231                 res = strv_join(units, " ");
 232                 if (!res)
 233                         return log_oom();
 234 #pragma GCC diagnostic push
 235 #pragma GCC diagnostic ignored "-Wformat-nonliteral"
 236                 fprintf(f, format, res);
 237 #pragma GCC diagnostic pop
 238         }
 239
 240         return 0;
 241 }
 242
 243 static int write_after(FILE *f, const char *opts) {
 244         return write_dependency(f, opts, "x-systemd.after", "After=%1$s\n");
 245 }
 246
 247 static int write_requires_after(FILE *f, const char *opts) {
 248         return write_dependency(f, opts,
 249                                 "x-systemd.requires", "After=%1$s\nRequires=%1$s\n");
 250 }
 251
 252 static int write_before(FILE *f, const char *opts) {
 253         return write_dependency(f, opts,
 254                                 "x-systemd.before", "Before=%1$s\n");
 255 }
 256
 257 static int write_requires_mounts_for(FILE *f, const char *opts) {
 258         _cleanup_strv_free_ char **paths = NULL, **paths_escaped = NULL;
 259         _cleanup_free_ char *res = NULL;
 260         int r;
 261
 262         assert(f);
 263         assert(opts);
 264
 265         r = fstab_extract_values(opts, "x-systemd.requires-mounts-for", &paths);
 266         if (r < 0)
 267                 return log_warning_errno(r, "Failed to parse options: %m");
 268         if (r == 0)
 269                 return 0;
 270
 271         r = specifier_escape_strv(paths, &paths_escaped);
 272         if (r < 0)
 273                 return log_error_errno(r, "Failed to escape paths: %m");
 274
 275         res = strv_join(paths_escaped, " ");
 276         if (!res)
 277                 return log_oom();
 278
 279         fprintf(f, "RequiresMountsFor=%s\n", res);
 280
 281         return 0;
 282 }
 283
 284 static int add_mount(
 285                 const char *dest,
 286                 const char *what,
 287                 const char *where,
 288                 const char *original_where,
 289                 const char *fstype,
 290                 const char *opts,
 291                 int passno,
 292                 MountpointFlags flags,
 293                 const char *post,
 294                 const char *source) {
 295
 296         _cleanup_free_ char
 297                 *name = NULL,
 298                 *automount_name = NULL,
 299                 *filtered = NULL,
 300                 *where_escaped = NULL;
 301         _cleanup_fclose_ FILE *f = NULL;
 302         int r;
 303
 304         assert(what);
 305         assert(where);
 306         assert(opts);
 307         assert(post);
 308         assert(source);
 309
 310         if (streq_ptr(fstype, "autofs"))
 311                 return 0;
 312
 313         if (!is_path(where)) {
 314                 log_warning("Mount point %s is not a valid path, ignoring.", where);
 315                 return 0;
 316         }
 317
 318         if (mount_point_is_api(where) ||
 319             mount_point_ignore(where))
 320                 return 0;
 321
 322         if (path_equal(where, "/")) {
 323                 if (flags & NOAUTO)
 324                         log_warning("Ignoring \"noauto\" for root device");
 325                 if (flags & NOFAIL)
 326                         log_warning("Ignoring \"nofail\" for root device");
 327                 if (flags & AUTOMOUNT)
 328                         log_warning("Ignoring automount option for root device");
 329
 330                 SET_FLAG(flags, NOAUTO | NOFAIL | AUTOMOUNT, false);
 331         }
 332
 333         r = unit_name_from_path(where, ".mount", &name);
 334         if (r < 0)
 335                 return log_error_errno(r, "Failed to generate unit name: %m");
 336
 337         r = generator_open_unit_file(dest, "/etc/fstab", name, &f);
 338         if (r < 0)
 339                 return r;
 340
 341         fprintf(f,
 342                 "[Unit]\n"
 343                 "SourcePath=%s\n"
 344                 "Documentation=man:fstab(5) man:systemd-fstab-generator(8)\n",
 345                 source);
 346
 347         if (STRPTR_IN_SET(fstype, "nfs", "nfs4") && !(flags & AUTOMOUNT) &&
 348             fstab_test_yes_no_option(opts, "bg\0" "fg\0")) {
 349                 /* The default retry timeout that mount.nfs uses for 'bg' mounts
 350                  * is 10000 minutes, where as it uses 2 minutes for 'fg' mounts.
 351                  * As we are making  'bg' mounts look like an 'fg' mount to
 352                  * mount.nfs (so systemd can manage the job-control aspects of 'bg'),
 353                  * we need to explicitly preserve that default, and also ensure
 354                  * the systemd mount-timeout doesn't interfere.
 355                  * By placing these options first, they can be over-ridden by
 356                  * settings in /etc/fstab. */
 357                 opts = strjoina("x-systemd.mount-timeout=infinity,retry=10000,", opts, ",fg");
 358                 SET_FLAG(flags, NOFAIL, true);
 359         }
 360
 361         if (!(flags & NOFAIL) && !(flags & AUTOMOUNT))
 362                 fprintf(f, "Before=%s\n", post);
 363
 364         if (!(flags & AUTOMOUNT) && opts) {
 365                  r = write_after(f, opts);
 366                  if (r < 0)
 367                          return r;
 368                  r = write_requires_after(f, opts);
 369                  if (r < 0)
 370                          return r;
 371                  r = write_before(f, opts);
 372                  if (r < 0)
 373                          return r;
 374                  r = write_requires_mounts_for(f, opts);
 375                  if (r < 0)
 376                          return r;
 377         }
 378
 379         if (passno != 0) {
 380                 r = generator_write_fsck_deps(f, dest, what, where, fstype);
 381                 if (r < 0)
 382                         return r;
 383         }
 384
 385         fprintf(f, "\n[Mount]\n");
 386         if (original_where)
 387                 fprintf(f, "# Canonicalized from %s\n", original_where);
 388
 389         where_escaped = specifier_escape(where);
 390         if (!where_escaped)
 391                 return log_oom();
 392         fprintf(f, "Where=%s\n", where_escaped);
 393
 394         r = write_what(f, what);
 395         if (r < 0)
 396                 return r;
 397
 398         if (!isempty(fstype) && !streq(fstype, "auto")) {
 399                 _cleanup_free_ char *t;
 400
 401                 t = specifier_escape(fstype);
 402                 if (!t)
 403                         return -ENOMEM;
 404
 405                 fprintf(f, "Type=%s\n", t);
 406         }
 407
 408         r = generator_write_timeouts(dest, what, where, opts, &filtered);
 409         if (r < 0)
 410                 return r;
 411
 412         r = generator_write_device_deps(dest, what, where, opts);
 413         if (r < 0)
 414                 return r;
 415
 416         r = write_mount_timeout(f, where, opts);
 417         if (r < 0)
 418                 return r;
 419
 420         r = write_options(f, filtered);
 421         if (r < 0)
 422                 return r;
 423
 424         r = fflush_and_check(f);
 425         if (r < 0)
 426                 return log_error_errno(r, "Failed to write unit file %s: %m", name);
 427
 428         if (flags & MAKEFS) {
 429                 r = generator_hook_up_mkfs(dest, what, where, fstype);
 430                 if (r < 0)
 431                         return r;
 432         }
 433
 434         if (flags & GROWFS) {
 435                 r = generator_hook_up_growfs(dest, where, post);
 436                 if (r < 0)
 437                         return r;
 438         }
 439
 440         if (!(flags & NOAUTO) && !(flags & AUTOMOUNT)) {
 441                 r = generator_add_symlink(dest, post,
 442                                           (flags & NOFAIL) ? "wants" : "requires", name);
 443                 if (r < 0)
 444                         return r;
 445         }
 446
 447         if (flags & AUTOMOUNT) {
 448                 r = unit_name_from_path(where, ".automount", &automount_name);
 449                 if (r < 0)
 450                         return log_error_errno(r, "Failed to generate unit name: %m");
 451
 452                 fclose(f);
 453
 454                 r = generator_open_unit_file(dest, "/etc/fstab", automount_name, &f);
 455                 if (r < 0)
 456                         return r;
 457
 458                 fprintf(f,
 459                         "[Unit]\n"
 460                         "SourcePath=%s\n"
 461                         "Documentation=man:fstab(5) man:systemd-fstab-generator(8)\n",
 462                         source);
 463
 464                 fprintf(f, "Before=%s\n", post);
 465
 466                 if (opts) {
 467                         r = write_after(f, opts);
 468                         if (r < 0)
 469                                 return r;
 470                         r = write_requires_after(f, opts);
 471                         if (r < 0)
 472                                 return r;
 473                         r = write_before(f, opts);
 474                         if (r < 0)
 475                                 return r;
 476                         r = write_requires_mounts_for(f, opts);
 477                         if (r < 0)
 478                                 return r;
 479                 }
 480
 481                 fprintf(f,
 482                         "\n"
 483                         "[Automount]\n"
 484                         "Where=%s\n",
 485                         where_escaped);
 486
 487                 r = write_idle_timeout(f, where, opts);
 488                 if (r < 0)
 489                         return r;
 490
 491                 r = fflush_and_check(f);
 492                 if (r < 0)
 493                         return log_error_errno(r, "Failed to write unit file %s: %m", automount_name);
 494
 495                 r = generator_add_symlink(dest, post,
 496                                           (flags & NOFAIL) ? "wants" : "requires", automount_name);
 497                 if (r < 0)
 498                         return r;
 499         }
 500
 501         return 0;
 502 }
 503
 504 static int parse_fstab(bool initrd) {
 505         _cleanup_endmntent_ FILE *f = NULL;
 506         const char *fstab_path;
 507         struct mntent *me;
 508         int r = 0;
 509
 510         fstab_path = initrd ? "/sysroot/etc/fstab" : "/etc/fstab";
 511         f = setmntent(fstab_path, "re");
 512         if (!f) {
 513                 if (errno == ENOENT)
 514                         return 0;
 515
 516                 return log_error_errno(errno, "Failed to open %s: %m", fstab_path);
 517         }
 518
 519         while ((me = getmntent(f))) {
 520                 _cleanup_free_ char *where = NULL, *what = NULL, *canonical_where = NULL;
 521                 bool makefs, growfs, noauto, nofail;
 522                 int k;
 523
 524                 if (initrd && !mount_in_initrd(me))
 525                         continue;
 526
 527                 what = fstab_node_to_udev_node(me->mnt_fsname);
 528                 if (!what)
 529                         return log_oom();
 530
 531                 if (is_device_path(what) && path_is_read_only_fs("sys") > 0) {
 532                         log_info("Running in a container, ignoring fstab device entry for %s.", what);
 533                         continue;
 534                 }
 535
 536                 where = strdup(me->mnt_dir);
 537                 if (!where)
 538                         return log_oom();
 539
 540                 if (is_path(where)) {
 541                         path_simplify(where, false);
 542
 543                         /* Follow symlinks here; see 5261ba901845c084de5a8fd06500ed09bfb0bd80 which makes sense for
 544                          * mount units, but causes problems since it historically worked to have symlinks in e.g.
 545                          * /etc/fstab. So we canonicalize here. Note that we use CHASE_NONEXISTENT to handle the case
 546                          * where a symlink refers to another mount target; this works assuming the sub-mountpoint
 547                          * target is the final directory. */
 548                         r = chase_symlinks(where, initrd ? "/sysroot" : NULL,
 549                                            CHASE_PREFIX_ROOT | CHASE_NONEXISTENT,
 550                                            &canonical_where);
 551                         if (r < 0) /* If we can't canonicalize we continue on as if it wasn't a symlink */
 552                                 log_debug_errno(r, "Failed to read symlink target for %s, ignoring: %m", where);
 553                         else if (streq(canonical_where, where)) /* If it was fully canonicalized, suppress the change */
 554                                 canonical_where = mfree(canonical_where);
 555                         else
 556                                 log_debug("Canonicalized what=%s where=%s to %s", what, where, canonical_where);
 557                 }
 558
 559                 makefs = fstab_test_option(me->mnt_opts, "x-systemd.makefs\0");
 560                 growfs = fstab_test_option(me->mnt_opts, "x-systemd.growfs\0");
 561                 noauto = fstab_test_yes_no_option(me->mnt_opts, "noauto\0" "auto\0");
 562                 nofail = fstab_test_yes_no_option(me->mnt_opts, "nofail\0" "fail\0");
 563
 564                 log_debug("Found entry what=%s where=%s type=%s makefs=%s nofail=%s noauto=%s",
 565                           what, where, me->mnt_type,
 566                           yes_no(makefs),
 567                           yes_no(noauto), yes_no(nofail));
 568
 569                 if (streq(me->mnt_type, "swap"))
 570                         k = add_swap(what, me,
 571                                      makefs*MAKEFS | growfs*GROWFS | noauto*NOAUTO | nofail*NOFAIL);
 572                 else {
 573                         bool automount;
 574                         const char *post;
 575
 576                         automount = fstab_test_option(me->mnt_opts,
 577                                                       "comment=systemd.automount\0"
 578                                                       "x-systemd.automount\0");
 579                         if (initrd)
 580                                 post = SPECIAL_INITRD_FS_TARGET;
 581                         else if (mount_is_network(me))
 582                                 post = SPECIAL_REMOTE_FS_TARGET;
 583                         else
 584                                 post = SPECIAL_LOCAL_FS_TARGET;
 585
 586                         k = add_mount(arg_dest,
 587                                       what,
 588                                       canonical_where ?: where,
 589                                       canonical_where ? where: NULL,
 590                                       me->mnt_type,
 591                                       me->mnt_opts,
 592                                       me->mnt_passno,
 593                                       makefs*MAKEFS | growfs*GROWFS | noauto*NOAUTO | nofail*NOFAIL | automount*AUTOMOUNT,
 594                                       post,
 595                                       fstab_path);
 596                 }
 597
 598                 if (r >= 0 && k < 0)
 599                         r = k;
 600         }
 601
 602         return r;
 603 }
 604
 605 static int add_sysroot_mount(void) {
 606         _cleanup_free_ char *what = NULL;
 607         const char *opts;
 608         int r;
 609
 610         if (isempty(arg_root_what)) {
 611                 log_debug("Could not find a root= entry on the kernel command line.");
 612                 return 0;
 613         }
 614
 615         if (streq(arg_root_what, "gpt-auto")) {
 616                 /* This is handled by the gpt-auto generator */
 617                 log_debug("Skipping root directory handling, as gpt-auto was requested.");
 618                 return 0;
 619         }
 620
 621         if (path_equal(arg_root_what, "/dev/nfs")) {
 622                 /* This is handled by the kernel or the initrd */
 623                 log_debug("Skipping root directory handling, as /dev/nfs was requested.");
 624                 return 0;
 625         }
 626
 627         what = fstab_node_to_udev_node(arg_root_what);
 628         if (!what)
 629                 return log_oom();
 630
 631         if (!arg_root_options)
 632                 opts = arg_root_rw > 0 ? "rw" : "ro";
 633         else if (arg_root_rw >= 0 ||
 634                  !fstab_test_option(arg_root_options, "ro\0" "rw\0"))
 635                 opts = strjoina(arg_root_options, ",", arg_root_rw > 0 ? "rw" : "ro");
 636         else
 637                 opts = arg_root_options;
 638
 639         log_debug("Found entry what=%s where=/sysroot type=%s", what, strna(arg_root_fstype));
 640
 641         if (is_device_path(what)) {
 642                 r = generator_write_initrd_root_device_deps(arg_dest, what);
 643                 if (r < 0)
 644                         return r;
 645         }
 646
 647         return add_mount(arg_dest,
 648                          what,
 649                          "/sysroot",
 650                          NULL,
 651                          arg_root_fstype,
 652                          opts,
 653                          is_device_path(what) ? 1 : 0, /* passno */
 654                          0,                            /* makefs off, growfs off, noauto off, nofail off, automount off */
 655                          SPECIAL_INITRD_ROOT_FS_TARGET,
 656                          "/proc/cmdline");
 657 }
 658
 659 static int add_sysroot_usr_mount(void) {
 660         _cleanup_free_ char *what = NULL;
 661         const char *opts;
 662
 663         if (!arg_usr_what && !arg_usr_fstype && !arg_usr_options)
 664                 return 0;
 665
 666         if (arg_root_what && !arg_usr_what) {
 667                 /* Copy over the root device, in case the /usr mount just differs in a mount option (consider btrfs subvolumes) */
 668                 arg_usr_what = strdup(arg_root_what);
 669                 if (!arg_usr_what)
 670                         return log_oom();
 671         }
 672
 673         if (arg_root_fstype && !arg_usr_fstype) {
 674                 arg_usr_fstype = strdup(arg_root_fstype);
 675                 if (!arg_usr_fstype)
 676                         return log_oom();
 677         }
 678
 679         if (arg_root_options && !arg_usr_options) {
 680                 arg_usr_options = strdup(arg_root_options);
 681                 if (!arg_usr_options)
 682                         return log_oom();
 683         }
 684
 685         if (!arg_usr_what)
 686                 return 0;
 687
 688         what = fstab_node_to_udev_node(arg_usr_what);
 689         if (!what)
 690                 return log_oom();
 691
 692         if (!arg_usr_options)
 693                 opts = arg_root_rw > 0 ? "rw" : "ro";
 694         else if (!fstab_test_option(arg_usr_options, "ro\0" "rw\0"))
 695                 opts = strjoina(arg_usr_options, ",", arg_root_rw > 0 ? "rw" : "ro");
 696         else
 697                 opts = arg_usr_options;
 698
 699         log_debug("Found entry what=%s where=/sysroot/usr type=%s", what, strna(arg_usr_fstype));
 700         return add_mount(arg_dest,
 701                          what,
 702                          "/sysroot/usr",
 703                          NULL,
 704                          arg_usr_fstype,
 705                          opts,
 706                          is_device_path(what) ? 1 : 0, /* passno */
 707                          0,
 708                          SPECIAL_INITRD_FS_TARGET,
 709                          "/proc/cmdline");
 710 }
 711
 712 static int add_volatile_root(void) {
 713         const char *from, *to;
 714
 715         if (arg_volatile_mode != VOLATILE_YES)
 716                 return 0;
 717
 718         /* Let's add in systemd-remount-volatile.service which will remount the root device to tmpfs if this is
 719          * requested, leaving only /usr from the root mount inside. */
 720
 721         from = strjoina(SYSTEM_DATA_UNIT_PATH "/systemd-volatile-root.service");
 722         to = strjoina(arg_dest, "/" SPECIAL_INITRD_ROOT_FS_TARGET, ".requires/systemd-volatile-root.service");
 723
 724         (void) mkdir_parents(to, 0755);
 725
 726         if (symlink(from, to) < 0)
 727                 return log_error_errno(errno, "Failed to hook in volatile remount service: %m");
 728
 729         return 0;
 730 }
 731
 732 static int add_volatile_var(void) {
 733
 734         if (arg_volatile_mode != VOLATILE_STATE)
 735                 return 0;
 736
 737         /* If requested, mount /var as tmpfs, but do so only if there's nothing else defined for this. */
 738
 739         return add_mount(arg_dest_late,
 740                          "tmpfs",
 741                          "/var",
 742                          NULL,
 743                          "tmpfs",
 744                          "mode=0755",
 745                          0,
 746                          0,
 747                          SPECIAL_LOCAL_FS_TARGET,
 748                          "/proc/cmdline");
 749 }
 750
 751 static int parse_proc_cmdline_item(const char *key, const char *value, void *data) {
 752         int r;
 753
 754         /* root=, usr=, usrfstype= and roofstype= may occur more than once, the last
 755          * instance should take precedence.  In the case of multiple rootflags=
 756          * or usrflags= the arguments should be concatenated */
 757
 758         if (STR_IN_SET(key, "fstab", "rd.fstab")) {
 759
 760                 r = value ? parse_boolean(value) : 1;
 761                 if (r < 0)
 762                         log_warning("Failed to parse fstab switch %s. Ignoring.", value);
 763                 else
 764                         arg_fstab_enabled = r;
 765
 766         } else if (streq(key, "root")) {
 767
 768                 if (proc_cmdline_value_missing(key, value))
 769                         return 0;
 770
 771                 if (free_and_strdup(&arg_root_what, value) < 0)
 772                         return log_oom();
 773
 774         } else if (streq(key, "rootfstype")) {
 775
 776                 if (proc_cmdline_value_missing(key, value))
 777                         return 0;
 778
 779                 if (free_and_strdup(&arg_root_fstype, value) < 0)
 780                         return log_oom();
 781
 782         } else if (streq(key, "rootflags")) {
 783
 784                 if (proc_cmdline_value_missing(key, value))
 785                         return 0;
 786
 787                 if (!strextend_with_separator(&arg_root_options, ",", value, NULL))
 788                         return log_oom();
 789
 790         } else if (streq(key, "roothash")) {
 791
 792                 if (proc_cmdline_value_missing(key, value))
 793                         return 0;
 794
 795                 if (free_and_strdup(&arg_root_hash, value) < 0)
 796                         return log_oom();
 797
 798         } else if (streq(key, "mount.usr")) {
 799
 800                 if (proc_cmdline_value_missing(key, value))
 801                         return 0;
 802
 803                 if (free_and_strdup(&arg_usr_what, value) < 0)
 804                         return log_oom();
 805
 806         } else if (streq(key, "mount.usrfstype")) {
 807
 808                 if (proc_cmdline_value_missing(key, value))
 809                         return 0;
 810
 811                 if (free_and_strdup(&arg_usr_fstype, value) < 0)
 812                         return log_oom();
 813
 814         } else if (streq(key, "mount.usrflags")) {
 815
 816                 if (proc_cmdline_value_missing(key, value))
 817                         return 0;
 818
 819                 if (!strextend_with_separator(&arg_usr_options, ",", value, NULL))
 820                         return log_oom();
 821
 822         } else if (streq(key, "rw") && !value)
 823                 arg_root_rw = true;
 824         else if (streq(key, "ro") && !value)
 825                 arg_root_rw = false;
 826         else if (streq(key, "systemd.volatile")) {
 827                 VolatileMode m;
 828
 829                 if (value) {
 830                         m = volatile_mode_from_string(value);
 831                         if (m < 0)
 832                                 log_warning("Failed to parse systemd.volatile= argument: %s", value);
 833                         else
 834                                 arg_volatile_mode = m;
 835                 } else
 836                         arg_volatile_mode = VOLATILE_YES;
 837         }
 838
 839         return 0;
 840 }
 841
 842 static int determine_root(void) {
 843         /* If we have a root hash but no root device then Verity is used, and we use the "root" DM device as root. */
 844
 845         if (arg_root_what)
 846                 return 0;
 847
 848         if (!arg_root_hash)
 849                 return 0;
 850
 851         arg_root_what = strdup("/dev/mapper/root");
 852         if (!arg_root_what)
 853                 return log_oom();
 854
 855         log_info("Using verity root device %s.", arg_root_what);
 856
 857         return 1;
 858 }
 859
 860 int main(int argc, char *argv[]) {
 861         int r = 0;
 862
 863         if (argc > 1 && argc != 4) {
 864                 log_error("This program takes three or no arguments.");
 865                 return EXIT_FAILURE;
 866         }
 867
 868         if (argc > 1)
 869                 arg_dest = argv[1];
 870         if (argc > 3)
 871                 arg_dest_late = argv[3];
 872
 873         log_set_prohibit_ipc(true);
 874         log_set_target(LOG_TARGET_AUTO);
 875         log_parse_environment();
 876         log_open();
 877
 878         umask(0022);
 879
 880         r = proc_cmdline_parse(parse_proc_cmdline_item, NULL, 0);
 881         if (r < 0)
 882                 log_warning_errno(r, "Failed to parse kernel command line, ignoring: %m");
 883
 884         (void) determine_root();
 885
 886         /* Always honour root= and usr= in the kernel command line if we are in an initrd */
 887         if (in_initrd()) {
 888                 int k;
 889
 890                 r = add_sysroot_mount();
 891
 892                 k = add_sysroot_usr_mount();
 893                 if (k < 0)
 894                         r = k;
 895
 896                 k = add_volatile_root();
 897                 if (k < 0)
 898                         r = k;
 899         } else
 900                 r = add_volatile_var();
 901
 902         /* Honour /etc/fstab only when that's enabled */
 903         if (arg_fstab_enabled) {
 904                 int k;
 905
 906                 log_debug("Parsing /etc/fstab");
 907
 908                 /* Parse the local /etc/fstab, possibly from the initrd */
 909                 k = parse_fstab(false);
 910                 if (k < 0)
 911                         r = k;
 912
 913                 /* If running in the initrd also parse the /etc/fstab from the host */
 914                 if (in_initrd()) {
 915                         log_debug("Parsing /sysroot/etc/fstab");
 916
 917                         k = parse_fstab(true);
 918                         if (k < 0)
 919                                 r = k;
 920                 }
 921         }
 922
 923         free(arg_root_what);
 924         free(arg_root_fstype);
 925         free(arg_root_options);
 926         free(arg_root_hash);
 927
 928         free(arg_usr_what);
 929         free(arg_usr_fstype);
 930         free(arg_usr_options);
 931
 932         return r < 0 ? EXIT_FAILURE : EXIT_SUCCESS;
 933 }