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         struct block_device *bdev = dev_to_bdev(dev);
  80         const struct uuidcmp *cmp = data;
  81
  82         if (!bdev->bd_meta_info ||
  83             strncasecmp(cmp->uuid, bdev->bd_meta_info->uuid, cmp->len))
  84                 return 0;
  85         return 1;
  86 }
  87
  88 /**
  89  * devt_from_partuuid - looks up the dev_t of a partition by its UUID
  90  * @uuid_str:   char array containing ascii UUID
  91  *
  92  * The function will return the first partition which contains a matching
  93  * UUID value in its partition_meta_info struct.  This does not search
  94  * by filesystem UUIDs.
  95  *
  96  * If @uuid_str is followed by a "/PARTNROFF=%d", then the number will be
  97  * extracted and used as an offset from the partition identified by the UUID.
  98  *
  99  * Returns the matching dev_t on success or 0 on failure.
 100  */
 101 static dev_t devt_from_partuuid(const char *uuid_str)
 102 {
 103         struct uuidcmp cmp;
 104         struct device *dev = NULL;
 105         dev_t devt = 0;
 106         int offset = 0;
 107         char *slash;
 108
 109         cmp.uuid = uuid_str;
 110
 111         slash = strchr(uuid_str, '/');
 112         /* Check for optional partition number offset attributes. */
 113         if (slash) {
 114                 char c = 0;
 115
 116                 /* Explicitly fail on poor PARTUUID syntax. */
 117                 if (sscanf(slash + 1, "PARTNROFF=%d%c", &offset, &c) != 1)
 118                         goto clear_root_wait;
 119                 cmp.len = slash - uuid_str;
 120         } else {
 121                 cmp.len = strlen(uuid_str);
 122         }
 123
 124         if (!cmp.len)
 125                 goto clear_root_wait;
 126
 127         dev = class_find_device(&block_class, NULL, &cmp, &match_dev_by_uuid);
 128         if (!dev)
 129                 return 0;
 130
 131         if (offset) {
 132                 /*
 133                  * Attempt to find the requested partition by adding an offset
 134                  * to the partition number found by UUID.
 135                  */
 136                 devt = part_devt(dev_to_disk(dev),
 137                                  dev_to_bdev(dev)->bd_partno + offset);
 138         } else {
 139                 devt = dev->devt;
 140         }
 141
 142         put_device(dev);
 143         return devt;
 144
 145 clear_root_wait:
 146         pr_err("VFS: PARTUUID= is invalid.\n"
 147                "Expected PARTUUID=<valid-uuid-id>[/PARTNROFF=%%d]\n");
 148         if (root_wait)
 149                 pr_err("Disabling rootwait; root= is invalid.\n");
 150         root_wait = 0;
 151         return 0;
 152 }
 153
 154 /**
 155  * match_dev_by_label - callback for finding a partition using its label
 156  * @dev:        device passed in by the caller
 157  * @data:       opaque pointer to the label to match
 158  *
 159  * Returns 1 if the device matches, and 0 otherwise.
 160  */
 161 static int match_dev_by_label(struct device *dev, const void *data)
 162 {
 163         struct block_device *bdev = dev_to_bdev(dev);
 164         const char *label = data;
 165
 166         if (!bdev->bd_meta_info || strcmp(label, bdev->bd_meta_info->volname))
 167                 return 0;
 168         return 1;
 169 }
 170
 171 static dev_t devt_from_partlabel(const char *label)
 172 {
 173         struct device *dev;
 174         dev_t devt = 0;
 175
 176         dev = class_find_device(&block_class, NULL, label, &match_dev_by_label);
 177         if (dev) {
 178                 devt = dev->devt;
 179                 put_device(dev);
 180         }
 181
 182         return devt;
 183 }
 184
 185 static dev_t devt_from_devname(const char *name)
 186 {
 187         dev_t devt = 0;
 188         int part;
 189         char s[32];
 190         char *p;
 191
 192         if (strlen(name) > 31)
 193                 return 0;
 194         strcpy(s, name);
 195         for (p = s; *p; p++) {
 196                 if (*p == '/')
 197                         *p = '!';
 198         }
 199
 200         devt = blk_lookup_devt(s, 0);
 201         if (devt)
 202                 return devt;
 203
 204         /*
 205          * Try non-existent, but valid partition, which may only exist after
 206          * opening the device, like partitioned md devices.
 207          */
 208         while (p > s && isdigit(p[-1]))
 209                 p--;
 210         if (p == s || !*p || *p == '0')
 211                 return 0;
 212
 213         /* try disk name without <part number> */
 214         part = simple_strtoul(p, NULL, 10);
 215         *p = '\0';
 216         devt = blk_lookup_devt(s, part);
 217         if (devt)
 218                 return devt;
 219
 220         /* try disk name without p<part number> */
 221         if (p < s + 2 || !isdigit(p[-2]) || p[-1] != 'p')
 222                 return 0;
 223         p[-1] = '\0';
 224         return blk_lookup_devt(s, part);
 225 }
 226 #endif /* CONFIG_BLOCK */
 227
 228 static dev_t devt_from_devnum(const char *name)
 229 {
 230         unsigned maj, min, offset;
 231         dev_t devt = 0;
 232         char *p, dummy;
 233
 234         if (sscanf(name, "%u:%u%c", &maj, &min, &dummy) == 2 ||
 235             sscanf(name, "%u:%u:%u:%c", &maj, &min, &offset, &dummy) == 3) {
 236                 devt = MKDEV(maj, min);
 237                 if (maj != MAJOR(devt) || min != MINOR(devt))
 238                         return 0;
 239         } else {
 240                 devt = new_decode_dev(simple_strtoul(name, &p, 16));
 241                 if (*p)
 242                         return 0;
 243         }
 244
 245         return devt;
 246 }
 247
 248 /*
 249  *      Convert a name into device number.  We accept the following variants:
 250  *
 251  *      1) <hex_major><hex_minor> device number in hexadecimal represents itself
 252  *         no leading 0x, for example b302.
 253  *      2) /dev/nfs represents Root_NFS (0xff)
 254  *      3) /dev/<disk_name> represents the device number of disk
 255  *      4) /dev/<disk_name><decimal> represents the device number
 256  *         of partition - device number of disk plus the partition number
 257  *      5) /dev/<disk_name>p<decimal> - same as the above, that form is
 258  *         used when disk name of partitioned disk ends on a digit.
 259  *      6) PARTUUID=00112233-4455-6677-8899-AABBCCDDEEFF representing the
 260  *         unique id of a partition if the partition table provides it.
 261  *         The UUID may be either an EFI/GPT UUID, or refer to an MSDOS
 262  *         partition using the format SSSSSSSS-PP, where SSSSSSSS is a zero-
 263  *         filled hex representation of the 32-bit "NT disk signature", and PP
 264  *         is a zero-filled hex representation of the 1-based partition number.
 265  *      7) PARTUUID=<UUID>/PARTNROFF=<int> to select a partition in relation to
 266  *         a partition with a known unique id.
 267  *      8) <major>:<minor> major and minor number of the device separated by
 268  *         a colon.
 269  *      9) PARTLABEL=<name> with name being the GPT partition label.
 270  *         MSDOS partitions do not support labels!
 271  *      10) /dev/cifs represents Root_CIFS (0xfe)
 272  *
 273  *      If name doesn't have fall into the categories above, we return (0,0).
 274  *      block_class is used to check if something is a disk name. If the disk
 275  *      name contains slashes, the device name has them replaced with
 276  *      bangs.
 277  */
 278 dev_t name_to_dev_t(const char *name)
 279 {
 280         if (strcmp(name, "/dev/nfs") == 0)
 281                 return Root_NFS;
 282         if (strcmp(name, "/dev/cifs") == 0)
 283                 return Root_CIFS;
 284         if (strcmp(name, "/dev/ram") == 0)
 285                 return Root_RAM0;
 286 #ifdef CONFIG_BLOCK
 287         if (strncmp(name, "PARTUUID=", 9) == 0)
 288                 return devt_from_partuuid(name + 9);
 289         if (strncmp(name, "PARTLABEL=", 10) == 0)
 290                 return devt_from_partlabel(name + 10);
 291         if (strncmp(name, "/dev/", 5) == 0)
 292                 return devt_from_devname(name + 5);
 293 #endif
 294         return devt_from_devnum(name);
 295 }
 296 EXPORT_SYMBOL_GPL(name_to_dev_t);
 297
 298 static int __init root_dev_setup(char *line)
 299 {
 300         strlcpy(saved_root_name, line, sizeof(saved_root_name));
 301         return 1;
 302 }
 303
 304 __setup("root=", root_dev_setup);
 305
 306 static int __init rootwait_setup(char *str)
 307 {
 308         if (*str)
 309                 return 0;
 310         root_wait = 1;
 311         return 1;
 312 }
 313
 314 __setup("rootwait", rootwait_setup);
 315
 316 static char * __initdata root_mount_data;
 317 static int __init root_data_setup(char *str)
 318 {
 319         root_mount_data = str;
 320         return 1;
 321 }
 322
 323 static char * __initdata root_fs_names;
 324 static int __init fs_names_setup(char *str)
 325 {
 326         root_fs_names = str;
 327         return 1;
 328 }
 329
 330 static unsigned int __initdata root_delay;
 331 static int __init root_delay_setup(char *str)
 332 {
 333         root_delay = simple_strtoul(str, NULL, 0);
 334         return 1;
 335 }
 336
 337 __setup("rootflags=", root_data_setup);
 338 __setup("rootfstype=", fs_names_setup);
 339 __setup("rootdelay=", root_delay_setup);
 340
 341 /* This can return zero length strings. Caller should check */
 342 static int __init split_fs_names(char *page, size_t size, char *names)
 343 {
 344         int count = 1;
 345         char *p = page;
 346
 347         strlcpy(p, root_fs_names, size);
 348         while (*p++) {
 349                 if (p[-1] == ',') {
 350                         p[-1] = '\0';
 351                         count++;
 352                 }
 353         }
 354
 355         return count;
 356 }
 357
 358 static int __init do_mount_root(const char *name, const char *fs,
 359                                  const int flags, const void *data)
 360 {
 361         struct super_block *s;
 362         struct page *p = NULL;
 363         char *data_page = NULL;
 364         int ret;
 365
 366         if (data) {
 367                 /* init_mount() requires a full page as fifth argument */
 368                 p = alloc_page(GFP_KERNEL);
 369                 if (!p)
 370                         return -ENOMEM;
 371                 data_page = page_address(p);
 372                 /* zero-pad. init_mount() will make sure it's terminated */
 373                 strncpy(data_page, data, PAGE_SIZE);
 374         }
 375
 376         ret = init_mount(name, "/root", fs, flags, data_page);
 377         if (ret)
 378                 goto out;
 379
 380         init_chdir("/root");
 381         s = current->fs->pwd.dentry->d_sb;
 382         ROOT_DEV = s->s_dev;
 383         printk(KERN_INFO
 384                "VFS: Mounted root (%s filesystem)%s on device %u:%u.\n",
 385                s->s_type->name,
 386                sb_rdonly(s) ? " readonly" : "",
 387                MAJOR(ROOT_DEV), MINOR(ROOT_DEV));
 388
 389 out:
 390         if (p)
 391                 put_page(p);
 392         return ret;
 393 }
 394
 395 void __init mount_block_root(char *name, int flags)
 396 {
 397         struct page *page = alloc_page(GFP_KERNEL);
 398         char *fs_names = page_address(page);
 399         char *p;
 400         char b[BDEVNAME_SIZE];
 401         int num_fs, i;
 402
 403         scnprintf(b, BDEVNAME_SIZE, "unknown-block(%u,%u)",
 404                   MAJOR(ROOT_DEV), MINOR(ROOT_DEV));
 405         if (root_fs_names)
 406                 num_fs = split_fs_names(fs_names, PAGE_SIZE, root_fs_names);
 407         else
 408                 num_fs = list_bdev_fs_names(fs_names, PAGE_SIZE);
 409 retry:
 410         for (i = 0, p = fs_names; i < num_fs; i++, p += strlen(p)+1) {
 411                 int err;
 412
 413                 if (!*p)
 414                         continue;
 415                 err = do_mount_root(name, p, flags, root_mount_data);
 416                 switch (err) {
 417                         case 0:
 418                                 goto out;
 419                         case -EACCES:
 420                         case -EINVAL:
 421                                 continue;
 422                 }
 423                 /*
 424                  * Allow the user to distinguish between failed sys_open
 425                  * and bad superblock on root device.
 426                  * and give them a list of the available devices
 427                  */
 428                 printk("VFS: Cannot open root device \"%s\" or %s: error %d\n",
 429                                 root_device_name, b, err);
 430                 printk("Please append a correct \"root=\" boot option; here are the available partitions:\n");
 431
 432                 printk_all_partitions();
 433                 panic("VFS: Unable to mount root fs on %s", b);
 434         }
 435         if (!(flags & SB_RDONLY)) {
 436                 flags |= SB_RDONLY;
 437                 goto retry;
 438         }
 439
 440         printk("List of all partitions:\n");
 441         printk_all_partitions();
 442         printk("No filesystem could mount root, tried: ");
 443         for (i = 0, p = fs_names; i < num_fs; i++, p += strlen(p)+1)
 444                 printk(" %s", p);
 445         printk("\n");
 446         panic("VFS: Unable to mount root fs on %s", b);
 447 out:
 448         put_page(page);
 449 }
 450
 451 #ifdef CONFIG_ROOT_NFS
 452
 453 #define NFSROOT_TIMEOUT_MIN     5
 454 #define NFSROOT_TIMEOUT_MAX     30
 455 #define NFSROOT_RETRY_MAX       5
 456
 457 static int __init mount_nfs_root(void)
 458 {
 459         char *root_dev, *root_data;
 460         unsigned int timeout;
 461         int try, err;
 462
 463         err = nfs_root_data(&root_dev, &root_data);
 464         if (err != 0)
 465                 return 0;
 466
 467         /*
 468          * The server or network may not be ready, so try several
 469          * times.  Stop after a few tries in case the client wants
 470          * to fall back to other boot methods.
 471          */
 472         timeout = NFSROOT_TIMEOUT_MIN;
 473         for (try = 1; ; try++) {
 474                 err = do_mount_root(root_dev, "nfs",
 475                                         root_mountflags, root_data);
 476                 if (err == 0)
 477                         return 1;
 478                 if (try > NFSROOT_RETRY_MAX)
 479                         break;
 480
 481                 /* Wait, in case the server refused us immediately */
 482                 ssleep(timeout);
 483                 timeout <<= 1;
 484                 if (timeout > NFSROOT_TIMEOUT_MAX)
 485                         timeout = NFSROOT_TIMEOUT_MAX;
 486         }
 487         return 0;
 488 }
 489 #endif
 490
 491 #ifdef CONFIG_CIFS_ROOT
 492
 493 extern int cifs_root_data(char **dev, char **opts);
 494
 495 #define CIFSROOT_TIMEOUT_MIN    5
 496 #define CIFSROOT_TIMEOUT_MAX    30
 497 #define CIFSROOT_RETRY_MAX      5
 498
 499 static int __init mount_cifs_root(void)
 500 {
 501         char *root_dev, *root_data;
 502         unsigned int timeout;
 503         int try, err;
 504
 505         err = cifs_root_data(&root_dev, &root_data);
 506         if (err != 0)
 507                 return 0;
 508
 509         timeout = CIFSROOT_TIMEOUT_MIN;
 510         for (try = 1; ; try++) {
 511                 err = do_mount_root(root_dev, "cifs", root_mountflags,
 512                                     root_data);
 513                 if (err == 0)
 514                         return 1;
 515                 if (try > CIFSROOT_RETRY_MAX)
 516                         break;
 517
 518                 ssleep(timeout);
 519                 timeout <<= 1;
 520                 if (timeout > CIFSROOT_TIMEOUT_MAX)
 521                         timeout = CIFSROOT_TIMEOUT_MAX;
 522         }
 523         return 0;
 524 }
 525 #endif
 526
 527 static bool __init fs_is_nodev(char *fstype)
 528 {
 529         struct file_system_type *fs = get_fs_type(fstype);
 530         bool ret = false;
 531
 532         if (fs) {
 533                 ret = !(fs->fs_flags & FS_REQUIRES_DEV);
 534                 put_filesystem(fs);
 535         }
 536
 537         return ret;
 538 }
 539
 540 static int __init mount_nodev_root(void)
 541 {
 542         char *fs_names, *fstype;
 543         int err = -EINVAL;
 544         int num_fs, i;
 545
 546         fs_names = (void *)__get_free_page(GFP_KERNEL);
 547         if (!fs_names)
 548                 return -EINVAL;
 549         num_fs = split_fs_names(fs_names, PAGE_SIZE, root_fs_names);
 550
 551         for (i = 0, fstype = fs_names; i < num_fs;
 552              i++, fstype += strlen(fstype) + 1) {
 553                 if (!*fstype)
 554                         continue;
 555                 if (!fs_is_nodev(fstype))
 556                         continue;
 557                 err = do_mount_root(root_device_name, fstype, root_mountflags,
 558                                     root_mount_data);
 559                 if (!err)
 560                         break;
 561         }
 562
 563         free_page((unsigned long)fs_names);
 564         return err;
 565 }
 566
 567 void __init mount_root(void)
 568 {
 569 #ifdef CONFIG_ROOT_NFS
 570         if (ROOT_DEV == Root_NFS) {
 571                 if (!mount_nfs_root())
 572                         printk(KERN_ERR "VFS: Unable to mount root fs via NFS.\n");
 573                 return;
 574         }
 575 #endif
 576 #ifdef CONFIG_CIFS_ROOT
 577         if (ROOT_DEV == Root_CIFS) {
 578                 if (!mount_cifs_root())
 579                         printk(KERN_ERR "VFS: Unable to mount root fs via SMB.\n");
 580                 return;
 581         }
 582 #endif
 583         if (ROOT_DEV == 0 && root_device_name && root_fs_names) {
 584                 if (mount_nodev_root() == 0)
 585                         return;
 586         }
 587 #ifdef CONFIG_BLOCK
 588         {
 589                 int err = create_dev("/dev/root", ROOT_DEV);
 590
 591                 if (err < 0)
 592                         pr_emerg("Failed to create /dev/root: %d\n", err);
 593                 mount_block_root("/dev/root", root_mountflags);
 594         }
 595 #endif
 596 }
 597
 598 /*
 599  * Prepare the namespace - decide what/where to mount, load ramdisks, etc.
 600  */
 601 void __init prepare_namespace(void)
 602 {
 603         int err;
 604
 605         if (root_delay) {
 606                 printk(KERN_INFO "Waiting %d sec before mounting root device...\n",
 607                        root_delay);
 608                 ssleep(root_delay);
 609         }
 610
 611         /*
 612          * wait for the known devices to complete their probing
 613          *
 614          * Note: this is a potential source of long boot delays.
 615          * For example, it is not atypical to wait 5 seconds here
 616          * for the touchpad of a laptop to initialize.
 617          */
 618         wait_for_device_probe();
 619
 620         md_run_setup();
 621
 622         if (saved_root_name[0]) {
 623                 root_device_name = saved_root_name;
 624                 if (!strncmp(root_device_name, "mtd", 3) ||
 625                     !strncmp(root_device_name, "ubi", 3)) {
 626                         mount_block_root(root_device_name, root_mountflags);
 627                         goto out;
 628                 }
 629                 ROOT_DEV = name_to_dev_t(root_device_name);
 630                 if (strncmp(root_device_name, "/dev/", 5) == 0)
 631                         root_device_name += 5;
 632         }
 633
 634         if (initrd_load())
 635                 goto out;
 636
 637         /* wait for any asynchronous scanning to complete */
 638         if ((ROOT_DEV == 0) && root_wait) {
 639                 printk(KERN_INFO "Waiting for root device %s...\n",
 640                         saved_root_name);
 641                 while (driver_probe_done() != 0 ||
 642                         (ROOT_DEV = name_to_dev_t(saved_root_name)) == 0)
 643                         msleep(5);
 644                 async_synchronize_full();
 645         }
 646
 647         mount_root();
 648 out:
 649         devtmpfs_mount();
 650         init_mount(".", "/", NULL, MS_MOVE, NULL);
 651         init_chroot(".");
 652 #ifdef CONFIG_BLOCK
 653         /* recreate the /dev/root */
 654         err = create_dev("/dev/root", ROOT_DEV);
 655
 656         if (err < 0)
 657                 pr_emerg("Failed to create /dev/root: %d\n", err);
 658 #endif
 659 }
 660
 661 static bool is_tmpfs;
 662 static int rootfs_init_fs_context(struct fs_context *fc)
 663 {
 664         if (IS_ENABLED(CONFIG_TMPFS) && is_tmpfs)
 665                 return shmem_init_fs_context(fc);
 666
 667         return ramfs_init_fs_context(fc);
 668 }
 669
 670 struct file_system_type rootfs_fs_type = {
 671         .name           = "rootfs",
 672         .init_fs_context = rootfs_init_fs_context,
 673         .kill_sb        = kill_litter_super,
 674 };
 675
 676 void __init init_rootfs(void)
 677 {
 678         if (IS_ENABLED(CONFIG_TMPFS) && !saved_root_name[0] &&
 679                 (!root_fs_names || strstr(root_fs_names, "tmpfs")))
 680                 is_tmpfs = true;
 681 }