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
  26 #include "do_mounts.h"
  27
  28 int __initdata rd_doload;       /* 1 = load RAM disk, 0 = don't load */
  29
  30 int root_mountflags = MS_RDONLY | MS_SILENT;
  31 static char * __initdata root_device_name;
  32 static char __initdata saved_root_name[64];
  33 static int root_wait;
  34
  35 dev_t ROOT_DEV;
  36
  37 static int __init load_ramdisk(char *str)
  38 {
  39         rd_doload = simple_strtol(str,NULL,0) & 3;
  40         return 1;
  41 }
  42 __setup("load_ramdisk=", load_ramdisk);
  43
  44 static int __init readonly(char *str)
  45 {
  46         if (*str)
  47                 return 0;
  48         root_mountflags |= MS_RDONLY;
  49         return 1;
  50 }
  51
  52 static int __init readwrite(char *str)
  53 {
  54         if (*str)
  55                 return 0;
  56         root_mountflags &= ~MS_RDONLY;
  57         return 1;
  58 }
  59
  60 __setup("ro", readonly);
  61 __setup("rw", readwrite);
  62
  63 #ifdef CONFIG_BLOCK
  64 struct uuidcmp {
  65         const char *uuid;
  66         int len;
  67 };
  68
  69 /**
  70  * match_dev_by_uuid - callback for finding a partition using its uuid
  71  * @dev:        device passed in by the caller
  72  * @data:       opaque pointer to the desired struct uuidcmp to match
  73  *
  74  * Returns 1 if the device matches, and 0 otherwise.
  75  */
  76 static int match_dev_by_uuid(struct device *dev, const void *data)
  77 {
  78         const struct uuidcmp *cmp = data;
  79         struct hd_struct *part = dev_to_part(dev);
  80
  81         if (!part->info)
  82                 goto no_match;
  83
  84         if (strncasecmp(cmp->uuid, part->info->uuid, cmp->len))
  85                 goto no_match;
  86
  87         return 1;
  88 no_match:
  89         return 0;
  90 }
  91
  92
  93 /**
  94  * devt_from_partuuid - looks up the dev_t of a partition by its UUID
  95  * @uuid_str:   char array containing ascii UUID
  96  *
  97  * The function will return the first partition which contains a matching
  98  * UUID value in its partition_meta_info struct.  This does not search
  99  * by filesystem UUIDs.
 100  *
 101  * If @uuid_str is followed by a "/PARTNROFF=%d", then the number will be
 102  * extracted and used as an offset from the partition identified by the UUID.
 103  *
 104  * Returns the matching dev_t on success or 0 on failure.
 105  */
 106 static dev_t devt_from_partuuid(const char *uuid_str)
 107 {
 108         dev_t res = 0;
 109         struct uuidcmp cmp;
 110         struct device *dev = NULL;
 111         struct gendisk *disk;
 112         struct hd_struct *part;
 113         int offset = 0;
 114         bool clear_root_wait = false;
 115         char *slash;
 116
 117         cmp.uuid = uuid_str;
 118
 119         slash = strchr(uuid_str, '/');
 120         /* Check for optional partition number offset attributes. */
 121         if (slash) {
 122                 char c = 0;
 123                 /* Explicitly fail on poor PARTUUID syntax. */
 124                 if (sscanf(slash + 1,
 125                            "PARTNROFF=%d%c", &offset, &c) != 1) {
 126                         clear_root_wait = true;
 127                         goto done;
 128                 }
 129                 cmp.len = slash - uuid_str;
 130         } else {
 131                 cmp.len = strlen(uuid_str);
 132         }
 133
 134         if (!cmp.len) {
 135                 clear_root_wait = true;
 136                 goto done;
 137         }
 138
 139         dev = class_find_device(&block_class, NULL, &cmp,
 140                                 &match_dev_by_uuid);
 141         if (!dev)
 142                 goto done;
 143
 144         res = dev->devt;
 145
 146         /* Attempt to find the partition by offset. */
 147         if (!offset)
 148                 goto no_offset;
 149
 150         res = 0;
 151         disk = part_to_disk(dev_to_part(dev));
 152         part = disk_get_part(disk, dev_to_part(dev)->partno + offset);
 153         if (part) {
 154                 res = part_devt(part);
 155                 put_device(part_to_dev(part));
 156         }
 157
 158 no_offset:
 159         put_device(dev);
 160 done:
 161         if (clear_root_wait) {
 162                 pr_err("VFS: PARTUUID= is invalid.\n"
 163                        "Expected PARTUUID=<valid-uuid-id>[/PARTNROFF=%%d]\n");
 164                 if (root_wait)
 165                         pr_err("Disabling rootwait; root= is invalid.\n");
 166                 root_wait = 0;
 167         }
 168         return res;
 169 }
 170 #endif
 171
 172 /*
 173  *      Convert a name into device number.  We accept the following variants:
 174  *
 175  *      1) <hex_major><hex_minor> device number in hexadecimal represents itself
 176  *         no leading 0x, for example b302.
 177  *      2) /dev/nfs represents Root_NFS (0xff)
 178  *      3) /dev/<disk_name> represents the device number of disk
 179  *      4) /dev/<disk_name><decimal> represents the device number
 180  *         of partition - device number of disk plus the partition number
 181  *      5) /dev/<disk_name>p<decimal> - same as the above, that form is
 182  *         used when disk name of partitioned disk ends on a digit.
 183  *      6) PARTUUID=00112233-4455-6677-8899-AABBCCDDEEFF representing the
 184  *         unique id of a partition if the partition table provides it.
 185  *         The UUID may be either an EFI/GPT UUID, or refer to an MSDOS
 186  *         partition using the format SSSSSSSS-PP, where SSSSSSSS is a zero-
 187  *         filled hex representation of the 32-bit "NT disk signature", and PP
 188  *         is a zero-filled hex representation of the 1-based partition number.
 189  *      7) PARTUUID=<UUID>/PARTNROFF=<int> to select a partition in relation to
 190  *         a partition with a known unique id.
 191  *      8) <major>:<minor> major and minor number of the device separated by
 192  *         a colon.
 193  *
 194  *      If name doesn't have fall into the categories above, we return (0,0).
 195  *      block_class is used to check if something is a disk name. If the disk
 196  *      name contains slashes, the device name has them replaced with
 197  *      bangs.
 198  */
 199
 200 dev_t name_to_dev_t(const char *name)
 201 {
 202         char s[32];
 203         char *p;
 204         dev_t res = 0;
 205         int part;
 206
 207 #ifdef CONFIG_BLOCK
 208         if (strncmp(name, "PARTUUID=", 9) == 0) {
 209                 name += 9;
 210                 res = devt_from_partuuid(name);
 211                 if (!res)
 212                         goto fail;
 213                 goto done;
 214         }
 215 #endif
 216
 217         if (strncmp(name, "/dev/", 5) != 0) {
 218                 unsigned maj, min, offset;
 219                 char dummy;
 220
 221                 if ((sscanf(name, "%u:%u%c", &maj, &min, &dummy) == 2) ||
 222                     (sscanf(name, "%u:%u:%u:%c", &maj, &min, &offset, &dummy) == 3)) {
 223                         res = MKDEV(maj, min);
 224                         if (maj != MAJOR(res) || min != MINOR(res))
 225                                 goto fail;
 226                 } else {
 227                         res = new_decode_dev(simple_strtoul(name, &p, 16));
 228                         if (*p)
 229                                 goto fail;
 230                 }
 231                 goto done;
 232         }
 233
 234         name += 5;
 235         res = Root_NFS;
 236         if (strcmp(name, "nfs") == 0)
 237                 goto done;
 238         res = Root_RAM0;
 239         if (strcmp(name, "ram") == 0)
 240                 goto done;
 241
 242         if (strlen(name) > 31)
 243                 goto fail;
 244         strcpy(s, name);
 245         for (p = s; *p; p++)
 246                 if (*p == '/')
 247                         *p = '!';
 248         res = blk_lookup_devt(s, 0);
 249         if (res)
 250                 goto done;
 251
 252         /*
 253          * try non-existent, but valid partition, which may only exist
 254          * after revalidating the disk, like partitioned md devices
 255          */
 256         while (p > s && isdigit(p[-1]))
 257                 p--;
 258         if (p == s || !*p || *p == '0')
 259                 goto fail;
 260
 261         /* try disk name without <part number> */
 262         part = simple_strtoul(p, NULL, 10);
 263         *p = '\0';
 264         res = blk_lookup_devt(s, part);
 265         if (res)
 266                 goto done;
 267
 268         /* try disk name without p<part number> */
 269         if (p < s + 2 || !isdigit(p[-2]) || p[-1] != 'p')
 270                 goto fail;
 271         p[-1] = '\0';
 272         res = blk_lookup_devt(s, part);
 273         if (res)
 274                 goto done;
 275
 276 fail:
 277         return 0;
 278 done:
 279         return res;
 280 }
 281 EXPORT_SYMBOL_GPL(name_to_dev_t);
 282
 283 static int __init root_dev_setup(char *line)
 284 {
 285         strlcpy(saved_root_name, line, sizeof(saved_root_name));
 286         return 1;
 287 }
 288
 289 __setup("root=", root_dev_setup);
 290
 291 static int __init rootwait_setup(char *str)
 292 {
 293         if (*str)
 294                 return 0;
 295         root_wait = 1;
 296         return 1;
 297 }
 298
 299 __setup("rootwait", rootwait_setup);
 300
 301 static char * __initdata root_mount_data;
 302 static int __init root_data_setup(char *str)
 303 {
 304         root_mount_data = str;
 305         return 1;
 306 }
 307
 308 static char * __initdata root_fs_names;
 309 static int __init fs_names_setup(char *str)
 310 {
 311         root_fs_names = str;
 312         return 1;
 313 }
 314
 315 static unsigned int __initdata root_delay;
 316 static int __init root_delay_setup(char *str)
 317 {
 318         root_delay = simple_strtoul(str, NULL, 0);
 319         return 1;
 320 }
 321
 322 __setup("rootflags=", root_data_setup);
 323 __setup("rootfstype=", fs_names_setup);
 324 __setup("rootdelay=", root_delay_setup);
 325
 326 static void __init get_fs_names(char *page)
 327 {
 328         char *s = page;
 329
 330         if (root_fs_names) {
 331                 strcpy(page, root_fs_names);
 332                 while (*s++) {
 333                         if (s[-1] == ',')
 334                                 s[-1] = '\0';
 335                 }
 336         } else {
 337                 int len = get_filesystem_list(page);
 338                 char *p, *next;
 339
 340                 page[len] = '\0';
 341                 for (p = page-1; p; p = next) {
 342                         next = strchr(++p, '\n');
 343                         if (*p++ != '\t')
 344                                 continue;
 345                         while ((*s++ = *p++) != '\n')
 346                                 ;
 347                         s[-1] = '\0';
 348                 }
 349         }
 350         *s = '\0';
 351 }
 352
 353 static int __init do_mount_root(char *name, char *fs, int flags, void *data)
 354 {
 355         struct super_block *s;
 356         int err = ksys_mount(name, "/root", fs, flags, data);
 357         if (err)
 358                 return err;
 359
 360         ksys_chdir("/root");
 361         s = current->fs->pwd.dentry->d_sb;
 362         ROOT_DEV = s->s_dev;
 363         printk(KERN_INFO
 364                "VFS: Mounted root (%s filesystem)%s on device %u:%u.\n",
 365                s->s_type->name,
 366                sb_rdonly(s) ? " readonly" : "",
 367                MAJOR(ROOT_DEV), MINOR(ROOT_DEV));
 368         return 0;
 369 }
 370
 371 void __init mount_block_root(char *name, int flags)
 372 {
 373         struct page *page = alloc_page(GFP_KERNEL);
 374         char *fs_names = page_address(page);
 375         char *p;
 376 #ifdef CONFIG_BLOCK
 377         char b[BDEVNAME_SIZE];
 378 #else
 379         const char *b = name;
 380 #endif
 381
 382         get_fs_names(fs_names);
 383 retry:
 384         for (p = fs_names; *p; p += strlen(p)+1) {
 385                 int err = do_mount_root(name, p, flags, root_mount_data);
 386                 switch (err) {
 387                         case 0:
 388                                 goto out;
 389                         case -EACCES:
 390                         case -EINVAL:
 391                                 continue;
 392                 }
 393                 /*
 394                  * Allow the user to distinguish between failed sys_open
 395                  * and bad superblock on root device.
 396                  * and give them a list of the available devices
 397                  */
 398 #ifdef CONFIG_BLOCK
 399                 __bdevname(ROOT_DEV, b);
 400 #endif
 401                 printk("VFS: Cannot open root device \"%s\" or %s: error %d\n",
 402                                 root_device_name, b, err);
 403                 printk("Please append a correct \"root=\" boot option; here are the available partitions:\n");
 404
 405                 printk_all_partitions();
 406 #ifdef CONFIG_DEBUG_BLOCK_EXT_DEVT
 407                 printk("DEBUG_BLOCK_EXT_DEVT is enabled, you need to specify "
 408                        "explicit textual name for \"root=\" boot option.\n");
 409 #endif
 410                 panic("VFS: Unable to mount root fs on %s", b);
 411         }
 412         if (!(flags & SB_RDONLY)) {
 413                 flags |= SB_RDONLY;
 414                 goto retry;
 415         }
 416
 417         printk("List of all partitions:\n");
 418         printk_all_partitions();
 419         printk("No filesystem could mount root, tried: ");
 420         for (p = fs_names; *p; p += strlen(p)+1)
 421                 printk(" %s", p);
 422         printk("\n");
 423 #ifdef CONFIG_BLOCK
 424         __bdevname(ROOT_DEV, b);
 425 #endif
 426         panic("VFS: Unable to mount root fs on %s", b);
 427 out:
 428         put_page(page);
 429 }
 430
 431 #ifdef CONFIG_ROOT_NFS
 432
 433 #define NFSROOT_TIMEOUT_MIN     5
 434 #define NFSROOT_TIMEOUT_MAX     30
 435 #define NFSROOT_RETRY_MAX       5
 436
 437 static int __init mount_nfs_root(void)
 438 {
 439         char *root_dev, *root_data;
 440         unsigned int timeout;
 441         int try, err;
 442
 443         err = nfs_root_data(&root_dev, &root_data);
 444         if (err != 0)
 445                 return 0;
 446
 447         /*
 448          * The server or network may not be ready, so try several
 449          * times.  Stop after a few tries in case the client wants
 450          * to fall back to other boot methods.
 451          */
 452         timeout = NFSROOT_TIMEOUT_MIN;
 453         for (try = 1; ; try++) {
 454                 err = do_mount_root(root_dev, "nfs",
 455                                         root_mountflags, root_data);
 456                 if (err == 0)
 457                         return 1;
 458                 if (try > NFSROOT_RETRY_MAX)
 459                         break;
 460
 461                 /* Wait, in case the server refused us immediately */
 462                 ssleep(timeout);
 463                 timeout <<= 1;
 464                 if (timeout > NFSROOT_TIMEOUT_MAX)
 465                         timeout = NFSROOT_TIMEOUT_MAX;
 466         }
 467         return 0;
 468 }
 469 #endif
 470
 471 #if defined(CONFIG_BLK_DEV_RAM) || defined(CONFIG_BLK_DEV_FD)
 472 void __init change_floppy(char *fmt, ...)
 473 {
 474         struct termios termios;
 475         char buf[80];
 476         char c;
 477         int fd;
 478         va_list args;
 479         va_start(args, fmt);
 480         vsprintf(buf, fmt, args);
 481         va_end(args);
 482         fd = ksys_open("/dev/root", O_RDWR | O_NDELAY, 0);
 483         if (fd >= 0) {
 484                 ksys_ioctl(fd, FDEJECT, 0);
 485                 ksys_close(fd);
 486         }
 487         printk(KERN_NOTICE "VFS: Insert %s and press ENTER\n", buf);
 488         fd = ksys_open("/dev/console", O_RDWR, 0);
 489         if (fd >= 0) {
 490                 ksys_ioctl(fd, TCGETS, (long)&termios);
 491                 termios.c_lflag &= ~ICANON;
 492                 ksys_ioctl(fd, TCSETSF, (long)&termios);
 493                 ksys_read(fd, &c, 1);
 494                 termios.c_lflag |= ICANON;
 495                 ksys_ioctl(fd, TCSETSF, (long)&termios);
 496                 ksys_close(fd);
 497         }
 498 }
 499 #endif
 500
 501 void __init mount_root(void)
 502 {
 503 #ifdef CONFIG_ROOT_NFS
 504         if (ROOT_DEV == Root_NFS) {
 505                 if (mount_nfs_root())
 506                         return;
 507
 508                 printk(KERN_ERR "VFS: Unable to mount root fs via NFS, trying floppy.\n");
 509                 ROOT_DEV = Root_FD0;
 510         }
 511 #endif
 512 #ifdef CONFIG_BLK_DEV_FD
 513         if (MAJOR(ROOT_DEV) == FLOPPY_MAJOR) {
 514                 /* rd_doload is 2 for a dual initrd/ramload setup */
 515                 if (rd_doload==2) {
 516                         if (rd_load_disk(1)) {
 517                                 ROOT_DEV = Root_RAM1;
 518                                 root_device_name = NULL;
 519                         }
 520                 } else
 521                         change_floppy("root floppy");
 522         }
 523 #endif
 524 #ifdef CONFIG_BLOCK
 525         {
 526                 int err = create_dev("/dev/root", ROOT_DEV);
 527
 528                 if (err < 0)
 529                         pr_emerg("Failed to create /dev/root: %d\n", err);
 530                 mount_block_root("/dev/root", root_mountflags);
 531         }
 532 #endif
 533 }
 534
 535 /*
 536  * Prepare the namespace - decide what/where to mount, load ramdisks, etc.
 537  */
 538 void __init prepare_namespace(void)
 539 {
 540         int is_floppy;
 541
 542         if (root_delay) {
 543                 printk(KERN_INFO "Waiting %d sec before mounting root device...\n",
 544                        root_delay);
 545                 ssleep(root_delay);
 546         }
 547
 548         /*
 549          * wait for the known devices to complete their probing
 550          *
 551          * Note: this is a potential source of long boot delays.
 552          * For example, it is not atypical to wait 5 seconds here
 553          * for the touchpad of a laptop to initialize.
 554          */
 555         wait_for_device_probe();
 556
 557         md_run_setup();
 558
 559         if (saved_root_name[0]) {
 560                 root_device_name = saved_root_name;
 561                 if (!strncmp(root_device_name, "mtd", 3) ||
 562                     !strncmp(root_device_name, "ubi", 3)) {
 563                         mount_block_root(root_device_name, root_mountflags);
 564                         goto out;
 565                 }
 566                 ROOT_DEV = name_to_dev_t(root_device_name);
 567                 if (strncmp(root_device_name, "/dev/", 5) == 0)
 568                         root_device_name += 5;
 569         }
 570
 571         if (initrd_load())
 572                 goto out;
 573
 574         /* wait for any asynchronous scanning to complete */
 575         if ((ROOT_DEV == 0) && root_wait) {
 576                 printk(KERN_INFO "Waiting for root device %s...\n",
 577                         saved_root_name);
 578                 while (driver_probe_done() != 0 ||
 579                         (ROOT_DEV = name_to_dev_t(saved_root_name)) == 0)
 580                         msleep(5);
 581                 async_synchronize_full();
 582         }
 583
 584         is_floppy = MAJOR(ROOT_DEV) == FLOPPY_MAJOR;
 585
 586         if (is_floppy && rd_doload && rd_load_disk(0))
 587                 ROOT_DEV = Root_RAM0;
 588
 589         mount_root();
 590 out:
 591         devtmpfs_mount("dev");
 592         ksys_mount(".", "/", NULL, MS_MOVE, NULL);
 593         ksys_chroot(".");
 594 }
 595
 596 static bool is_tmpfs;
 597 static struct dentry *rootfs_mount(struct file_system_type *fs_type,
 598         int flags, const char *dev_name, void *data)
 599 {
 600         static unsigned long once;
 601         void *fill = ramfs_fill_super;
 602
 603         if (test_and_set_bit(0, &once))
 604                 return ERR_PTR(-ENODEV);
 605
 606         if (IS_ENABLED(CONFIG_TMPFS) && is_tmpfs)
 607                 fill = shmem_fill_super;
 608
 609         return mount_nodev(fs_type, flags, data, fill);
 610 }
 611
 612 static struct file_system_type rootfs_fs_type = {
 613         .name           = "rootfs",
 614         .mount          = rootfs_mount,
 615         .kill_sb        = kill_litter_super,
 616 };
 617
 618 int __init init_rootfs(void)
 619 {
 620         int err = register_filesystem(&rootfs_fs_type);
 621
 622         if (err)
 623                 return err;
 624
 625         if (IS_ENABLED(CONFIG_TMPFS) && !saved_root_name[0] &&
 626                 (!root_fs_names || strstr(root_fs_names, "tmpfs"))) {
 627                 err = shmem_init();
 628                 is_tmpfs = true;
 629         } else {
 630                 err = init_ramfs_fs();
 631         }
 632
 633         if (err)
 634                 unregister_filesystem(&rootfs_fs_type);
 635
 636         return err;
 637 }