init/do_mounts.c

   1 // SPDX-License-Identifier: GPL-2.0-only
   2 #include <linux/module.h>
   3 #include <linux/sched.h>
   4 #include <linux/ctype.h>
   5 #include <linux/fd.h>
   6 #include <linux/tty.h>
   7 #include <linux/suspend.h>
   8 #include <linux/root_dev.h>
   9 #include <linux/security.h>
  10 #include <linux/delay.h>
  11 #include <linux/genhd.h>
  12 #include <linux/mount.h>
  13 #include <linux/device.h>
  14 #include <linux/init.h>
  15 #include <linux/fs.h>
  16 #include <linux/initrd.h>
  17 #include <linux/async.h>
  18 #include <linux/fs_struct.h>
  19 #include <linux/slab.h>
  20 #include <linux/ramfs.h>
  21 #include <linux/shmem_fs.h>
  22
  23 #include <linux/nfs_fs.h>
  24 #include <linux/nfs_fs_sb.h>
  25 #include <linux/nfs_mount.h>
  26 #include <linux/raid/detect.h>
  27 #include <uapi/linux/mount.h>
  28
  29 #include "do_mounts.h"
  30
  31 int root_mountflags = MS_RDONLY | MS_SILENT;
  32 static char * __initdata root_device_name;
  33 static char __initdata saved_root_name[64];
  34 static int root_wait;
  35
  36 dev_t ROOT_DEV;
  37
  38 static int __init load_ramdisk(char *str)
  39 {
  40         pr_warn("ignoring the deprecated load_ramdisk= option\n");
  41         return 1;
  42 }
  43 __setup("load_ramdisk=", load_ramdisk);
  44
  45 static int __init readonly(char *str)
  46 {
  47         if (*str)
  48                 return 0;
  49         root_mountflags |= MS_RDONLY;
  50         return 1;
  51 }
  52
  53 static int __init readwrite(char *str)
  54 {
  55         if (*str)
  56                 return 0;
  57         root_mountflags &= ~MS_RDONLY;
  58         return 1;
  59 }
  60
  61 __setup("ro", readonly);
  62 __setup("rw", readwrite);
  63
  64 #ifdef CONFIG_BLOCK
  65 struct uuidcmp {
  66         const char *uuid;
  67         int len;
  68 };
  69
  70 /**
  71  * match_dev_by_uuid - callback for finding a partition using its uuid
  72  * @dev:        device passed in by the caller
  73  * @data:       opaque pointer to the desired struct uuidcmp to match
  74  *
  75  * Returns 1 if the device matches, and 0 otherwise.
  76  */
  77 static int match_dev_by_uuid(struct device *dev, const void *data)
  78 {
  79         const struct uuidcmp *cmp = data;
  80         struct hd_struct *part = dev_to_part(dev);
  81
  82         if (!part->info)
  83                 goto no_match;
  84
  85         if (strncasecmp(cmp->uuid, part->info->uuid, cmp->len))
  86                 goto no_match;
  87
  88         return 1;
  89 no_match:
  90         return 0;
  91 }
  92
  93
  94 /**
  95  * devt_from_partuuid - looks up the dev_t of a partition by its UUID
  96  * @uuid_str:   char array containing ascii UUID
  97  *
  98  * The function will return the first partition which contains a matching
  99  * UUID value in its partition_meta_info struct.  This does not search
 100  * by filesystem UUIDs.
 101  *
 102  * If @uuid_str is followed by a "/PARTNROFF=%d", then the number will be
 103  * extracted and used as an offset from the partition identified by the UUID.
 104  *
 105  * Returns the matching dev_t on success or 0 on failure.
 106  */
 107 static dev_t devt_from_partuuid(const char *uuid_str)
 108 {
 109         dev_t res = 0;
 110         struct uuidcmp cmp;
 111         struct device *dev = NULL;
 112         struct gendisk *disk;
 113         struct hd_struct *part;
 114         int offset = 0;
 115         bool clear_root_wait = false;
 116         char *slash;
 117
 118         cmp.uuid = uuid_str;
 119
 120         slash = strchr(uuid_str, '/');
 121         /* Check for optional partition number offset attributes. */
 122         if (slash) {
 123                 char c = 0;
 124                 /* Explicitly fail on poor PARTUUID syntax. */
 125                 if (sscanf(slash + 1,
 126                            "PARTNROFF=%d%c", &offset, &c) != 1) {
 127                         clear_root_wait = true;
 128                         goto done;
 129                 }
 130                 cmp.len = slash - uuid_str;
 131         } else {
 132                 cmp.len = strlen(uuid_str);
 133         }
 134
 135         if (!cmp.len) {
 136                 clear_root_wait = true;
 137                 goto done;
 138         }
 139
 140         dev = class_find_device(&block_class, NULL, &cmp,
 141                                 &match_dev_by_uuid);
 142         if (!dev)
 143                 goto done;
 144
 145         res = dev->devt;
 146
 147         /* Attempt to find the partition by offset. */
 148         if (!offset)
 149                 goto no_offset;
 150
 151         res = 0;
 152         disk = part_to_disk(dev_to_part(dev));
 153         part = disk_get_part(disk, dev_to_part(dev)->partno + offset);
 154         if (part) {
 155                 res = part_devt(part);
 156                 put_device(part_to_dev(part));
 157         }
 158
 159 no_offset:
 160         put_device(dev);
 161 done:
 162         if (clear_root_wait) {
 163                 pr_err("VFS: PARTUUID= is invalid.\n"
 164                        "Expected PARTUUID=<valid-uuid-id>[/PARTNROFF=%%d]\n");
 165                 if (root_wait)
 166                         pr_err("Disabling rootwait; root= is invalid.\n");
 167                 root_wait = 0;
 168         }
 169         return res;
 170 }
 171
 172 /**
 173  * match_dev_by_label - callback for finding a partition using its label
 174  * @dev:        device passed in by the caller
 175  * @data:       opaque pointer to the label to match
 176  *
 177  * Returns 1 if the device matches, and 0 otherwise.
 178  */
 179 static int match_dev_by_label(struct device *dev, const void *data)
 180 {
 181         const char *label = data;
 182         struct hd_struct *part = dev_to_part(dev);
 183
 184         if (part->info && !strcmp(label, part->info->volname))
 185                 return 1;
 186
 187         return 0;
 188 }
 189 #endif
 190
 191 /*
 192  *      Convert a name into device number.  We accept the following variants:
 193  *
 194  *      1) <hex_major><hex_minor> device number in hexadecimal represents itself
 195  *         no leading 0x, for example b302.
 196  *      2) /dev/nfs represents Root_NFS (0xff)
 197  *      3) /dev/<disk_name> represents the device number of disk
 198  *      4) /dev/<disk_name><decimal> represents the device number
 199  *         of partition - device number of disk plus the partition number
 200  *      5) /dev/<disk_name>p<decimal> - same as the above, that form is
 201  *         used when disk name of partitioned disk ends on a digit.
 202  *      6) PARTUUID=00112233-4455-6677-8899-AABBCCDDEEFF representing the
 203  *         unique id of a partition if the partition table provides it.
 204  *         The UUID may be either an EFI/GPT UUID, or refer to an MSDOS
 205  *         partition using the format SSSSSSSS-PP, where SSSSSSSS is a zero-
 206  *         filled hex representation of the 32-bit "NT disk signature", and PP
 207  *         is a zero-filled hex representation of the 1-based partition number.
 208  *      7) PARTUUID=<UUID>/PARTNROFF=<int> to select a partition in relation to
 209  *         a partition with a known unique id.
 210  *      8) <major>:<minor> major and minor number of the device separated by
 211  *         a colon.
 212  *      9) PARTLABEL=<name> with name being the GPT partition label.
 213  *         MSDOS partitions do not support labels!
 214  *      10) /dev/cifs represents Root_CIFS (0xfe)
 215  *
 216  *      If name doesn't have fall into the categories above, we return (0,0).
 217  *      block_class is used to check if something is a disk name. If the disk
 218  *      name contains slashes, the device name has them replaced with
 219  *      bangs.
 220  */
 221
 222 dev_t name_to_dev_t(const char *name)
 223 {
 224         char s[32];
 225         char *p;
 226         dev_t res = 0;
 227         int part;
 228
 229 #ifdef CONFIG_BLOCK
 230         if (strncmp(name, "PARTUUID=", 9) == 0) {
 231                 name += 9;
 232                 res = devt_from_partuuid(name);
 233                 if (!res)
 234                         goto fail;
 235                 goto done;
 236         } else if (strncmp(name, "PARTLABEL=", 10) == 0) {
 237                 struct device *dev;
 238
 239                 dev = class_find_device(&block_class, NULL, name + 10,
 240                                         &match_dev_by_label);
 241                 if (!dev)
 242                         goto fail;
 243
 244                 res = dev->devt;
 245                 put_device(dev);
 246                 goto done;
 247         }
 248 #endif
 249
 250         if (strncmp(name, "/dev/", 5) != 0) {
 251                 unsigned maj, min, offset;
 252                 char dummy;
 253
 254                 if ((sscanf(name, "%u:%u%c", &maj, &min, &dummy) == 2) ||
 255                     (sscanf(name, "%u:%u:%u:%c", &maj, &min, &offset, &dummy) == 3)) {
 256                         res = MKDEV(maj, min);
 257                         if (maj != MAJOR(res) || min != MINOR(res))
 258                                 goto fail;
 259                 } else {
 260                         res = new_decode_dev(simple_strtoul(name, &p, 16));
 261                         if (*p)
 262                                 goto fail;
 263                 }
 264                 goto done;
 265         }
 266
 267         name += 5;
 268         res = Root_NFS;
 269         if (strcmp(name, "nfs") == 0)
 270                 goto done;
 271         res = Root_CIFS;
 272         if (strcmp(name, "cifs") == 0)
 273                 goto done;
 274         res = Root_RAM0;
 275         if (strcmp(name, "ram") == 0)
 276                 goto done;
 277
 278         if (strlen(name) > 31)
 279                 goto fail;
 280         strcpy(s, name);
 281         for (p = s; *p; p++)
 282                 if (*p == '/')
 283                         *p = '!';
 284         res = blk_lookup_devt(s, 0);
 285         if (res)
 286                 goto done;
 287
 288         /*
 289          * try non-existent, but valid partition, which may only exist
 290          * after revalidating the disk, like partitioned md devices
 291          */
 292         while (p > s && isdigit(p[-1]))
 293                 p--;
 294         if (p == s || !*p || *p == '0')
 295                 goto fail;
 296
 297         /* try disk name without <part number> */
 298         part = simple_strtoul(p, NULL, 10);
 299         *p = '\0';
 300         res = blk_lookup_devt(s, part);
 301         if (res)
 302                 goto done;
 303
 304         /* try disk name without p<part number> */
 305         if (p < s + 2 || !isdigit(p[-2]) || p[-1] != 'p')
 306                 goto fail;
 307         p[-1] = '\0';
 308         res = blk_lookup_devt(s, part);
 309         if (res)
 310                 goto done;
 311
 312 fail:
 313         return 0;
 314 done:
 315         return res;
 316 }
 317 EXPORT_SYMBOL_GPL(name_to_dev_t);
 318
 319 static int __init root_dev_setup(char *line)
 320 {
 321         strlcpy(saved_root_name, line, sizeof(saved_root_name));
 322         return 1;
 323 }
 324
 325 __setup("root=", root_dev_setup);
 326
 327 static int __init rootwait_setup(char *str)
 328 {
 329         if (*str)
 330                 return 0;
 331         root_wait = 1;
 332         return 1;
 333 }
 334
 335 __setup("rootwait", rootwait_setup);
 336
 337 static char * __initdata root_mount_data;
 338 static int __init root_data_setup(char *str)
 339 {
 340         root_mount_data = str;
 341         return 1;
 342 }
 343
 344 static char * __initdata root_fs_names;
 345 static int __init fs_names_setup(char *str)
 346 {
 347         root_fs_names = str;
 348         return 1;
 349 }
 350
 351 static unsigned int __initdata root_delay;
 352 static int __init root_delay_setup(char *str)
 353 {
 354         root_delay = simple_strtoul(str, NULL, 0);
 355         return 1;
 356 }
 357
 358 __setup("rootflags=", root_data_setup);
 359 __setup("rootfstype=", fs_names_setup);
 360 __setup("rootdelay=", root_delay_setup);
 361
 362 static void __init get_fs_names(char *page)
 363 {
 364         char *s = page;
 365
 366         if (root_fs_names) {
 367                 strcpy(page, root_fs_names);
 368                 while (*s++) {
 369                         if (s[-1] == ',')
 370                                 s[-1] = '\0';
 371                 }
 372         } else {
 373                 int len = get_filesystem_list(page);
 374                 char *p, *next;
 375
 376                 page[len] = '\0';
 377                 for (p = page-1; p; p = next) {
 378                         next = strchr(++p, '\n');
 379                         if (*p++ != '\t')
 380                                 continue;
 381                         while ((*s++ = *p++) != '\n')
 382                                 ;
 383                         s[-1] = '\0';
 384                 }
 385         }
 386         *s = '\0';
 387 }
 388
 389 static int __init do_mount_root(const char *name, const char *fs,
 390                                  const int flags, const void *data)
 391 {
 392         struct super_block *s;
 393         struct page *p = NULL;
 394         char *data_page = NULL;
 395         int ret;
 396
 397         if (data) {
 398                 /* do_mount() requires a full page as fifth argument */
 399                 p = alloc_page(GFP_KERNEL);
 400                 if (!p)
 401                         return -ENOMEM;
 402                 data_page = page_address(p);
 403                 /* zero-pad. do_mount() will make sure it's terminated */
 404                 strncpy(data_page, data, PAGE_SIZE);
 405         }
 406
 407         ret = do_mount(name, "/root", fs, flags, data_page);
 408         if (ret)
 409                 goto out;
 410
 411         ksys_chdir("/root");
 412         s = current->fs->pwd.dentry->d_sb;
 413         ROOT_DEV = s->s_dev;
 414         printk(KERN_INFO
 415                "VFS: Mounted root (%s filesystem)%s on device %u:%u.\n",
 416                s->s_type->name,
 417                sb_rdonly(s) ? " readonly" : "",
 418                MAJOR(ROOT_DEV), MINOR(ROOT_DEV));
 419
 420 out:
 421         if (p)
 422                 put_page(p);
 423         return ret;
 424 }
 425
 426 void __init mount_block_root(char *name, int flags)
 427 {
 428         struct page *page = alloc_page(GFP_KERNEL);
 429         char *fs_names = page_address(page);
 430         char *p;
 431         char b[BDEVNAME_SIZE];
 432
 433         scnprintf(b, BDEVNAME_SIZE, "unknown-block(%u,%u)",
 434                   MAJOR(ROOT_DEV), MINOR(ROOT_DEV));
 435         get_fs_names(fs_names);
 436 retry:
 437         for (p = fs_names; *p; p += strlen(p)+1) {
 438                 int err = do_mount_root(name, p, flags, root_mount_data);
 439                 switch (err) {
 440                         case 0:
 441                                 goto out;
 442                         case -EACCES:
 443                         case -EINVAL:
 444                                 continue;
 445                 }
 446                 /*
 447                  * Allow the user to distinguish between failed sys_open
 448                  * and bad superblock on root device.
 449                  * and give them a list of the available devices
 450                  */
 451                 printk("VFS: Cannot open root device \"%s\" or %s: error %d\n",
 452                                 root_device_name, b, err);
 453                 printk("Please append a correct \"root=\" boot option; here are the available partitions:\n");
 454
 455                 printk_all_partitions();
 456 #ifdef CONFIG_DEBUG_BLOCK_EXT_DEVT
 457                 printk("DEBUG_BLOCK_EXT_DEVT is enabled, you need to specify "
 458                        "explicit textual name for \"root=\" boot option.\n");
 459 #endif
 460                 panic("VFS: Unable to mount root fs on %s", b);
 461         }
 462         if (!(flags & SB_RDONLY)) {
 463                 flags |= SB_RDONLY;
 464                 goto retry;
 465         }
 466
 467         printk("List of all partitions:\n");
 468         printk_all_partitions();
 469         printk("No filesystem could mount root, tried: ");
 470         for (p = fs_names; *p; p += strlen(p)+1)
 471                 printk(" %s", p);
 472         printk("\n");
 473         panic("VFS: Unable to mount root fs on %s", b);
 474 out:
 475         put_page(page);
 476 }
 477
 478 #ifdef CONFIG_ROOT_NFS
 479
 480 #define NFSROOT_TIMEOUT_MIN     5
 481 #define NFSROOT_TIMEOUT_MAX     30
 482 #define NFSROOT_RETRY_MAX       5
 483
 484 static int __init mount_nfs_root(void)
 485 {
 486         char *root_dev, *root_data;
 487         unsigned int timeout;
 488         int try, err;
 489
 490         err = nfs_root_data(&root_dev, &root_data);
 491         if (err != 0)
 492                 return 0;
 493
 494         /*
 495          * The server or network may not be ready, so try several
 496          * times.  Stop after a few tries in case the client wants
 497          * to fall back to other boot methods.
 498          */
 499         timeout = NFSROOT_TIMEOUT_MIN;
 500         for (try = 1; ; try++) {
 501                 err = do_mount_root(root_dev, "nfs",
 502                                         root_mountflags, root_data);
 503                 if (err == 0)
 504                         return 1;
 505                 if (try > NFSROOT_RETRY_MAX)
 506                         break;
 507
 508                 /* Wait, in case the server refused us immediately */
 509                 ssleep(timeout);
 510                 timeout <<= 1;
 511                 if (timeout > NFSROOT_TIMEOUT_MAX)
 512                         timeout = NFSROOT_TIMEOUT_MAX;
 513         }
 514         return 0;
 515 }
 516 #endif
 517
 518 #ifdef CONFIG_CIFS_ROOT
 519
 520 extern int cifs_root_data(char **dev, char **opts);
 521
 522 #define CIFSROOT_TIMEOUT_MIN    5
 523 #define CIFSROOT_TIMEOUT_MAX    30
 524 #define CIFSROOT_RETRY_MAX      5
 525
 526 static int __init mount_cifs_root(void)
 527 {
 528         char *root_dev, *root_data;
 529         unsigned int timeout;
 530         int try, err;
 531
 532         err = cifs_root_data(&root_dev, &root_data);
 533         if (err != 0)
 534                 return 0;
 535
 536         timeout = CIFSROOT_TIMEOUT_MIN;
 537         for (try = 1; ; try++) {
 538                 err = do_mount_root(root_dev, "cifs", root_mountflags,
 539                                     root_data);
 540                 if (err == 0)
 541                         return 1;
 542                 if (try > CIFSROOT_RETRY_MAX)
 543                         break;
 544
 545                 ssleep(timeout);
 546                 timeout <<= 1;
 547                 if (timeout > CIFSROOT_TIMEOUT_MAX)
 548                         timeout = CIFSROOT_TIMEOUT_MAX;
 549         }
 550         return 0;
 551 }
 552 #endif
 553
 554 void __init mount_root(void)
 555 {
 556 #ifdef CONFIG_ROOT_NFS
 557         if (ROOT_DEV == Root_NFS) {
 558                 if (!mount_nfs_root())
 559                         printk(KERN_ERR "VFS: Unable to mount root fs via NFS.\n");
 560                 return;
 561         }
 562 #endif
 563 #ifdef CONFIG_CIFS_ROOT
 564         if (ROOT_DEV == Root_CIFS) {
 565                 if (!mount_cifs_root())
 566                         printk(KERN_ERR "VFS: Unable to mount root fs via SMB.\n");
 567                 return;
 568         }
 569 #endif
 570 #ifdef CONFIG_BLOCK
 571         {
 572                 int err = create_dev("/dev/root", ROOT_DEV);
 573
 574                 if (err < 0)
 575                         pr_emerg("Failed to create /dev/root: %d\n", err);
 576                 mount_block_root("/dev/root", root_mountflags);
 577         }
 578 #endif
 579 }
 580
 581 /*
 582  * Prepare the namespace - decide what/where to mount, load ramdisks, etc.
 583  */
 584 void __init prepare_namespace(void)
 585 {
 586         if (root_delay) {
 587                 printk(KERN_INFO "Waiting %d sec before mounting root device...\n",
 588                        root_delay);
 589                 ssleep(root_delay);
 590         }
 591
 592         /*
 593          * wait for the known devices to complete their probing
 594          *
 595          * Note: this is a potential source of long boot delays.
 596          * For example, it is not atypical to wait 5 seconds here
 597          * for the touchpad of a laptop to initialize.
 598          */
 599         wait_for_device_probe();
 600
 601         md_run_setup();
 602
 603         if (saved_root_name[0]) {
 604                 root_device_name = saved_root_name;
 605                 if (!strncmp(root_device_name, "mtd", 3) ||
 606                     !strncmp(root_device_name, "ubi", 3)) {
 607                         mount_block_root(root_device_name, root_mountflags);
 608                         goto out;
 609                 }
 610                 ROOT_DEV = name_to_dev_t(root_device_name);
 611                 if (strncmp(root_device_name, "/dev/", 5) == 0)
 612                         root_device_name += 5;
 613         }
 614
 615         if (initrd_load())
 616                 goto out;
 617
 618         /* wait for any asynchronous scanning to complete */
 619         if ((ROOT_DEV == 0) && root_wait) {
 620                 printk(KERN_INFO "Waiting for root device %s...\n",
 621                         saved_root_name);
 622                 while (driver_probe_done() != 0 ||
 623                         (ROOT_DEV = name_to_dev_t(saved_root_name)) == 0)
 624                         msleep(5);
 625                 async_synchronize_full();
 626         }
 627
 628         mount_root();
 629 out:
 630         devtmpfs_mount();
 631         do_mount(".", "/", NULL, MS_MOVE, NULL);
 632         ksys_chroot(".");
 633 }
 634
 635 static bool is_tmpfs;
 636 static int rootfs_init_fs_context(struct fs_context *fc)
 637 {
 638         if (IS_ENABLED(CONFIG_TMPFS) && is_tmpfs)
 639                 return shmem_init_fs_context(fc);
 640
 641         return ramfs_init_fs_context(fc);
 642 }
 643
 644 struct file_system_type rootfs_fs_type = {
 645         .name           = "rootfs",
 646         .init_fs_context = rootfs_init_fs_context,
 647         .kill_sb        = kill_litter_super,
 648 };
 649
 650 void __init init_rootfs(void)
 651 {
 652         if (IS_ENABLED(CONFIG_TMPFS) && !saved_root_name[0] &&
 653                 (!root_fs_names || strstr(root_fs_names, "tmpfs")))
 654                 is_tmpfs = true;
 655 }