init/do_mounts.c

   1 #include <linux/module.h>
   2 #include <linux/sched.h>
   3 #include <linux/ctype.h>
   4 #include <linux/fd.h>
   5 #include <linux/tty.h>
   6 #include <linux/suspend.h>
   7 #include <linux/root_dev.h>
   8 #include <linux/security.h>
   9 #include <linux/delay.h>
  10 #include <linux/genhd.h>
  11 #include <linux/mount.h>
  12 #include <linux/device.h>
  13 #include <linux/init.h>
  14 #include <linux/fs.h>
  15 #include <linux/initrd.h>
  16 #include <linux/async.h>
  17 #include <linux/fs_struct.h>
  18 #include <linux/slab.h>
  19 #include <linux/ramfs.h>
  20 #include <linux/shmem_fs.h>
  21
  22 #include <linux/nfs_fs.h>
  23 #include <linux/nfs_fs_sb.h>
  24 #include <linux/nfs_mount.h>
  25 #include <uapi/linux/mount.h>
  26
  27 #include "do_mounts.h"
  28
  29 int __initdata rd_doload;       /* 1 = load RAM disk, 0 = don't load */
  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         rd_doload = simple_strtol(str,NULL,0) & 3;
  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  *
 215  *      If name doesn't have fall into the categories above, we return (0,0).
 216  *      block_class is used to check if something is a disk name. If the disk
 217  *      name contains slashes, the device name has them replaced with
 218  *      bangs.
 219  */
 220
 221 dev_t name_to_dev_t(const char *name)
 222 {
 223         char s[32];
 224         char *p;
 225         dev_t res = 0;
 226         int part;
 227
 228 #ifdef CONFIG_BLOCK
 229         if (strncmp(name, "PARTUUID=", 9) == 0) {
 230                 name += 9;
 231                 res = devt_from_partuuid(name);
 232                 if (!res)
 233                         goto fail;
 234                 goto done;
 235         } else if (strncmp(name, "PARTLABEL=", 10) == 0) {
 236                 struct device *dev;
 237
 238                 dev = class_find_device(&block_class, NULL, name + 10,
 239                                         &match_dev_by_label);
 240                 if (!dev)
 241                         goto fail;
 242
 243                 res = dev->devt;
 244                 put_device(dev);
 245                 goto done;
 246         }
 247 #endif
 248
 249         if (strncmp(name, "/dev/", 5) != 0) {
 250                 unsigned maj, min, offset;
 251                 char dummy;
 252
 253                 if ((sscanf(name, "%u:%u%c", &maj, &min, &dummy) == 2) ||
 254                     (sscanf(name, "%u:%u:%u:%c", &maj, &min, &offset, &dummy) == 3)) {
 255                         res = MKDEV(maj, min);
 256                         if (maj != MAJOR(res) || min != MINOR(res))
 257                                 goto fail;
 258                 } else {
 259                         res = new_decode_dev(simple_strtoul(name, &p, 16));
 260                         if (*p)
 261                                 goto fail;
 262                 }
 263                 goto done;
 264         }
 265
 266         name += 5;
 267         res = Root_NFS;
 268         if (strcmp(name, "nfs") == 0)
 269                 goto done;
 270         res = Root_RAM0;
 271         if (strcmp(name, "ram") == 0)
 272                 goto done;
 273
 274         if (strlen(name) > 31)
 275                 goto fail;
 276         strcpy(s, name);
 277         for (p = s; *p; p++)
 278                 if (*p == '/')
 279                         *p = '!';
 280         res = blk_lookup_devt(s, 0);
 281         if (res)
 282                 goto done;
 283
 284         /*
 285          * try non-existent, but valid partition, which may only exist
 286          * after revalidating the disk, like partitioned md devices
 287          */
 288         while (p > s && isdigit(p[-1]))
 289                 p--;
 290         if (p == s || !*p || *p == '0')
 291                 goto fail;
 292
 293         /* try disk name without <part number> */
 294         part = simple_strtoul(p, NULL, 10);
 295         *p = '\0';
 296         res = blk_lookup_devt(s, part);
 297         if (res)
 298                 goto done;
 299
 300         /* try disk name without p<part number> */
 301         if (p < s + 2 || !isdigit(p[-2]) || p[-1] != 'p')
 302                 goto fail;
 303         p[-1] = '\0';
 304         res = blk_lookup_devt(s, part);
 305         if (res)
 306                 goto done;
 307
 308 fail:
 309         return 0;
 310 done:
 311         return res;
 312 }
 313 EXPORT_SYMBOL_GPL(name_to_dev_t);
 314
 315 static int __init root_dev_setup(char *line)
 316 {
 317         strlcpy(saved_root_name, line, sizeof(saved_root_name));
 318         return 1;
 319 }
 320
 321 __setup("root=", root_dev_setup);
 322
 323 static int __init rootwait_setup(char *str)
 324 {
 325         if (*str)
 326                 return 0;
 327         root_wait = 1;
 328         return 1;
 329 }
 330
 331 __setup("rootwait", rootwait_setup);
 332
 333 static char * __initdata root_mount_data;
 334 static int __init root_data_setup(char *str)
 335 {
 336         root_mount_data = str;
 337         return 1;
 338 }
 339
 340 static char * __initdata root_fs_names;
 341 static int __init fs_names_setup(char *str)
 342 {
 343         root_fs_names = str;
 344         return 1;
 345 }
 346
 347 static unsigned int __initdata root_delay;
 348 static int __init root_delay_setup(char *str)
 349 {
 350         root_delay = simple_strtoul(str, NULL, 0);
 351         return 1;
 352 }
 353
 354 __setup("rootflags=", root_data_setup);
 355 __setup("rootfstype=", fs_names_setup);
 356 __setup("rootdelay=", root_delay_setup);
 357
 358 static void __init get_fs_names(char *page)
 359 {
 360         char *s = page;
 361
 362         if (root_fs_names) {
 363                 strcpy(page, root_fs_names);
 364                 while (*s++) {
 365                         if (s[-1] == ',')
 366                                 s[-1] = '\0';
 367                 }
 368         } else {
 369                 int len = get_filesystem_list(page);
 370                 char *p, *next;
 371
 372                 page[len] = '\0';
 373                 for (p = page-1; p; p = next) {
 374                         next = strchr(++p, '\n');
 375                         if (*p++ != '\t')
 376                                 continue;
 377                         while ((*s++ = *p++) != '\n')
 378                                 ;
 379                         s[-1] = '\0';
 380                 }
 381         }
 382         *s = '\0';
 383 }
 384
 385 static int __init do_mount_root(char *name, char *fs, int flags, void *data)
 386 {
 387         struct super_block *s;
 388         int err = ksys_mount(name, "/root", fs, flags, data);
 389         if (err)
 390                 return err;
 391
 392         ksys_chdir("/root");
 393         s = current->fs->pwd.dentry->d_sb;
 394         ROOT_DEV = s->s_dev;
 395         printk(KERN_INFO
 396                "VFS: Mounted root (%s filesystem)%s on device %u:%u.\n",
 397                s->s_type->name,
 398                sb_rdonly(s) ? " readonly" : "",
 399                MAJOR(ROOT_DEV), MINOR(ROOT_DEV));
 400         return 0;
 401 }
 402
 403 void __init mount_block_root(char *name, int flags)
 404 {
 405         struct page *page = alloc_page(GFP_KERNEL);
 406         char *fs_names = page_address(page);
 407         char *p;
 408 #ifdef CONFIG_BLOCK
 409         char b[BDEVNAME_SIZE];
 410 #else
 411         const char *b = name;
 412 #endif
 413
 414         get_fs_names(fs_names);
 415 retry:
 416         for (p = fs_names; *p; p += strlen(p)+1) {
 417                 int err = do_mount_root(name, p, flags, root_mount_data);
 418                 switch (err) {
 419                         case 0:
 420                                 goto out;
 421                         case -EACCES:
 422                         case -EINVAL:
 423                                 continue;
 424                 }
 425                 /*
 426                  * Allow the user to distinguish between failed sys_open
 427                  * and bad superblock on root device.
 428                  * and give them a list of the available devices
 429                  */
 430 #ifdef CONFIG_BLOCK
 431                 __bdevname(ROOT_DEV, b);
 432 #endif
 433                 printk("VFS: Cannot open root device \"%s\" or %s: error %d\n",
 434                                 root_device_name, b, err);
 435                 printk("Please append a correct \"root=\" boot option; here are the available partitions:\n");
 436
 437                 printk_all_partitions();
 438 #ifdef CONFIG_DEBUG_BLOCK_EXT_DEVT
 439                 printk("DEBUG_BLOCK_EXT_DEVT is enabled, you need to specify "
 440                        "explicit textual name for \"root=\" boot option.\n");
 441 #endif
 442                 panic("VFS: Unable to mount root fs on %s", b);
 443         }
 444         if (!(flags & SB_RDONLY)) {
 445                 flags |= SB_RDONLY;
 446                 goto retry;
 447         }
 448
 449         printk("List of all partitions:\n");
 450         printk_all_partitions();
 451         printk("No filesystem could mount root, tried: ");
 452         for (p = fs_names; *p; p += strlen(p)+1)
 453                 printk(" %s", p);
 454         printk("\n");
 455 #ifdef CONFIG_BLOCK
 456         __bdevname(ROOT_DEV, b);
 457 #endif
 458         panic("VFS: Unable to mount root fs on %s", b);
 459 out:
 460         put_page(page);
 461 }
 462
 463 #ifdef CONFIG_ROOT_NFS
 464
 465 #define NFSROOT_TIMEOUT_MIN     5
 466 #define NFSROOT_TIMEOUT_MAX     30
 467 #define NFSROOT_RETRY_MAX       5
 468
 469 static int __init mount_nfs_root(void)
 470 {
 471         char *root_dev, *root_data;
 472         unsigned int timeout;
 473         int try, err;
 474
 475         err = nfs_root_data(&root_dev, &root_data);
 476         if (err != 0)
 477                 return 0;
 478
 479         /*
 480          * The server or network may not be ready, so try several
 481          * times.  Stop after a few tries in case the client wants
 482          * to fall back to other boot methods.
 483          */
 484         timeout = NFSROOT_TIMEOUT_MIN;
 485         for (try = 1; ; try++) {
 486                 err = do_mount_root(root_dev, "nfs",
 487                                         root_mountflags, root_data);
 488                 if (err == 0)
 489                         return 1;
 490                 if (try > NFSROOT_RETRY_MAX)
 491                         break;
 492
 493                 /* Wait, in case the server refused us immediately */
 494                 ssleep(timeout);
 495                 timeout <<= 1;
 496                 if (timeout > NFSROOT_TIMEOUT_MAX)
 497                         timeout = NFSROOT_TIMEOUT_MAX;
 498         }
 499         return 0;
 500 }
 501 #endif
 502
 503 #if defined(CONFIG_BLK_DEV_RAM) || defined(CONFIG_BLK_DEV_FD)
 504 void __init change_floppy(char *fmt, ...)
 505 {
 506         struct termios termios;
 507         char buf[80];
 508         char c;
 509         int fd;
 510         va_list args;
 511         va_start(args, fmt);
 512         vsprintf(buf, fmt, args);
 513         va_end(args);
 514         fd = ksys_open("/dev/root", O_RDWR | O_NDELAY, 0);
 515         if (fd >= 0) {
 516                 ksys_ioctl(fd, FDEJECT, 0);
 517                 ksys_close(fd);
 518         }
 519         printk(KERN_NOTICE "VFS: Insert %s and press ENTER\n", buf);
 520         fd = ksys_open("/dev/console", O_RDWR, 0);
 521         if (fd >= 0) {
 522                 ksys_ioctl(fd, TCGETS, (long)&termios);
 523                 termios.c_lflag &= ~ICANON;
 524                 ksys_ioctl(fd, TCSETSF, (long)&termios);
 525                 ksys_read(fd, &c, 1);
 526                 termios.c_lflag |= ICANON;
 527                 ksys_ioctl(fd, TCSETSF, (long)&termios);
 528                 ksys_close(fd);
 529         }
 530 }
 531 #endif
 532
 533 void __init mount_root(void)
 534 {
 535 #ifdef CONFIG_ROOT_NFS
 536         if (ROOT_DEV == Root_NFS) {
 537                 if (mount_nfs_root())
 538                         return;
 539
 540                 printk(KERN_ERR "VFS: Unable to mount root fs via NFS, trying floppy.\n");
 541                 ROOT_DEV = Root_FD0;
 542         }
 543 #endif
 544 #ifdef CONFIG_BLK_DEV_FD
 545         if (MAJOR(ROOT_DEV) == FLOPPY_MAJOR) {
 546                 /* rd_doload is 2 for a dual initrd/ramload setup */
 547                 if (rd_doload==2) {
 548                         if (rd_load_disk(1)) {
 549                                 ROOT_DEV = Root_RAM1;
 550                                 root_device_name = NULL;
 551                         }
 552                 } else
 553                         change_floppy("root floppy");
 554         }
 555 #endif
 556 #ifdef CONFIG_BLOCK
 557         {
 558                 int err = create_dev("/dev/root", ROOT_DEV);
 559
 560                 if (err < 0)
 561                         pr_emerg("Failed to create /dev/root: %d\n", err);
 562                 mount_block_root("/dev/root", root_mountflags);
 563         }
 564 #endif
 565 }
 566
 567 /*
 568  * Prepare the namespace - decide what/where to mount, load ramdisks, etc.
 569  */
 570 void __init prepare_namespace(void)
 571 {
 572         int is_floppy;
 573
 574         if (root_delay) {
 575                 printk(KERN_INFO "Waiting %d sec before mounting root device...\n",
 576                        root_delay);
 577                 ssleep(root_delay);
 578         }
 579
 580         /*
 581          * wait for the known devices to complete their probing
 582          *
 583          * Note: this is a potential source of long boot delays.
 584          * For example, it is not atypical to wait 5 seconds here
 585          * for the touchpad of a laptop to initialize.
 586          */
 587         wait_for_device_probe();
 588
 589         md_run_setup();
 590
 591         if (saved_root_name[0]) {
 592                 root_device_name = saved_root_name;
 593                 if (!strncmp(root_device_name, "mtd", 3) ||
 594                     !strncmp(root_device_name, "ubi", 3)) {
 595                         mount_block_root(root_device_name, root_mountflags);
 596                         goto out;
 597                 }
 598                 ROOT_DEV = name_to_dev_t(root_device_name);
 599                 if (strncmp(root_device_name, "/dev/", 5) == 0)
 600                         root_device_name += 5;
 601         }
 602
 603         if (initrd_load())
 604                 goto out;
 605
 606         /* wait for any asynchronous scanning to complete */
 607         if ((ROOT_DEV == 0) && root_wait) {
 608                 printk(KERN_INFO "Waiting for root device %s...\n",
 609                         saved_root_name);
 610                 while (driver_probe_done() != 0 ||
 611                         (ROOT_DEV = name_to_dev_t(saved_root_name)) == 0)
 612                         msleep(5);
 613                 async_synchronize_full();
 614         }
 615
 616         is_floppy = MAJOR(ROOT_DEV) == FLOPPY_MAJOR;
 617
 618         if (is_floppy && rd_doload && rd_load_disk(0))
 619                 ROOT_DEV = Root_RAM0;
 620
 621         mount_root();
 622 out:
 623         devtmpfs_mount("dev");
 624         ksys_mount(".", "/", NULL, MS_MOVE, NULL);
 625         ksys_chroot(".");
 626 }
 627
 628 static bool is_tmpfs;
 629 static struct dentry *rootfs_mount(struct file_system_type *fs_type,
 630         int flags, const char *dev_name, void *data)
 631 {
 632         static unsigned long once;
 633         void *fill = ramfs_fill_super;
 634
 635         if (test_and_set_bit(0, &once))
 636                 return ERR_PTR(-ENODEV);
 637
 638         if (IS_ENABLED(CONFIG_TMPFS) && is_tmpfs)
 639                 fill = shmem_fill_super;
 640
 641         return mount_nodev(fs_type, flags, data, fill);
 642 }
 643
 644 static struct file_system_type rootfs_fs_type = {
 645         .name           = "rootfs",
 646         .mount          = rootfs_mount,
 647         .kill_sb        = kill_litter_super,
 648 };
 649
 650 int __init init_rootfs(void)
 651 {
 652         int err = register_filesystem(&rootfs_fs_type);
 653
 654         if (err)
 655                 return err;
 656
 657         if (IS_ENABLED(CONFIG_TMPFS) && !saved_root_name[0] &&
 658                 (!root_fs_names || strstr(root_fs_names, "tmpfs"))) {
 659                 err = shmem_init();
 660                 is_tmpfs = true;
 661         } else {
 662                 err = init_ramfs_fs();
 663         }
 664
 665         if (err)
 666                 unregister_filesystem(&rootfs_fs_type);
 667
 668         return err;
 669 }