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
  20 #include <linux/nfs_fs.h>
  21 #include <linux/nfs_fs_sb.h>
  22 #include <linux/nfs_mount.h>
  23
  24 #include "do_mounts.h"
  25
  26 int __initdata rd_doload;       /* 1 = load RAM disk, 0 = don't load */
  27
  28 int root_mountflags = MS_RDONLY | MS_SILENT;
  29 static char * __initdata root_device_name;
  30 static char __initdata saved_root_name[64];
  31 static int root_wait;
  32
  33 dev_t ROOT_DEV;
  34
  35 static int __init load_ramdisk(char *str)
  36 {
  37         rd_doload = simple_strtol(str,NULL,0) & 3;
  38         return 1;
  39 }
  40 __setup("load_ramdisk=", load_ramdisk);
  41
  42 static int __init readonly(char *str)
  43 {
  44         if (*str)
  45                 return 0;
  46         root_mountflags |= MS_RDONLY;
  47         return 1;
  48 }
  49
  50 static int __init readwrite(char *str)
  51 {
  52         if (*str)
  53                 return 0;
  54         root_mountflags &= ~MS_RDONLY;
  55         return 1;
  56 }
  57
  58 __setup("ro", readonly);
  59 __setup("rw", readwrite);
  60
  61 #ifdef CONFIG_BLOCK
  62 /**
  63  * match_dev_by_uuid - callback for finding a partition using its uuid
  64  * @dev:        device passed in by the caller
  65  * @data:       opaque pointer to a 36 byte char array with a UUID
  66  *
  67  * Returns 1 if the device matches, and 0 otherwise.
  68  */
  69 static int match_dev_by_uuid(struct device *dev, void *data)
  70 {
  71         u8 *uuid = data;
  72         struct hd_struct *part = dev_to_part(dev);
  73
  74         if (!part->info)
  75                 goto no_match;
  76
  77         if (memcmp(uuid, part->info->uuid, sizeof(part->info->uuid)))
  78                         goto no_match;
  79
  80         return 1;
  81 no_match:
  82         return 0;
  83 }
  84
  85
  86 /**
  87  * devt_from_partuuid - looks up the dev_t of a partition by its UUID
  88  * @uuid:       min 36 byte char array containing a hex ascii UUID
  89  *
  90  * The function will return the first partition which contains a matching
  91  * UUID value in its partition_meta_info struct.  This does not search
  92  * by filesystem UUIDs.
  93  *
  94  * If @uuid is followed by a "/PARTNROFF=%d", then the number will be
  95  * extracted and used as an offset from the partition identified by the UUID.
  96  *
  97  * Returns the matching dev_t on success or 0 on failure.
  98  */
  99 static dev_t devt_from_partuuid(char *uuid_str)
 100 {
 101         dev_t res = 0;
 102         struct device *dev = NULL;
 103         u8 uuid[16];
 104         struct gendisk *disk;
 105         struct hd_struct *part;
 106         int offset = 0;
 107
 108         if (strlen(uuid_str) < 36)
 109                 goto done;
 110
 111         /* Check for optional partition number offset attributes. */
 112         if (uuid_str[36]) {
 113                 char c = 0;
 114                 /* Explicitly fail on poor PARTUUID syntax. */
 115                 if (sscanf(&uuid_str[36],
 116                            "/PARTNROFF=%d%c", &offset, &c) != 1) {
 117                         printk(KERN_ERR "VFS: PARTUUID= is invalid.\n"
 118                          "Expected PARTUUID=<valid-uuid-id>[/PARTNROFF=%%d]\n");
 119                         if (root_wait)
 120                                 printk(KERN_ERR
 121                                      "Disabling rootwait; root= is invalid.\n");
 122                         root_wait = 0;
 123                         goto done;
 124                 }
 125         }
 126
 127         /* Pack the requested UUID in the expected format. */
 128         part_pack_uuid(uuid_str, uuid);
 129
 130         dev = class_find_device(&block_class, NULL, uuid, &match_dev_by_uuid);
 131         if (!dev)
 132                 goto done;
 133
 134         res = dev->devt;
 135
 136         /* Attempt to find the partition by offset. */
 137         if (!offset)
 138                 goto no_offset;
 139
 140         res = 0;
 141         disk = part_to_disk(dev_to_part(dev));
 142         part = disk_get_part(disk, dev_to_part(dev)->partno + offset);
 143         if (part) {
 144                 res = part_devt(part);
 145                 put_device(part_to_dev(part));
 146         }
 147
 148 no_offset:
 149         put_device(dev);
 150 done:
 151         return res;
 152 }
 153 #endif
 154
 155 /*
 156  *      Convert a name into device number.  We accept the following variants:
 157  *
 158  *      1) device number in hexadecimal represents itself
 159  *      2) /dev/nfs represents Root_NFS (0xff)
 160  *      3) /dev/<disk_name> represents the device number of disk
 161  *      4) /dev/<disk_name><decimal> represents the device number
 162  *         of partition - device number of disk plus the partition number
 163  *      5) /dev/<disk_name>p<decimal> - same as the above, that form is
 164  *         used when disk name of partitioned disk ends on a digit.
 165  *      6) PARTUUID=00112233-4455-6677-8899-AABBCCDDEEFF representing the
 166  *         unique id of a partition if the partition table provides it.
 167  *      7) PARTUUID=<UUID>/PARTNROFF=<int> to select a partition in relation to
 168  *         a partition with a known unique id.
 169  *
 170  *      If name doesn't have fall into the categories above, we return (0,0).
 171  *      block_class is used to check if something is a disk name. If the disk
 172  *      name contains slashes, the device name has them replaced with
 173  *      bangs.
 174  */
 175
 176 dev_t name_to_dev_t(char *name)
 177 {
 178         char s[32];
 179         char *p;
 180         dev_t res = 0;
 181         int part;
 182
 183 #ifdef CONFIG_BLOCK
 184         if (strncmp(name, "PARTUUID=", 9) == 0) {
 185                 name += 9;
 186                 res = devt_from_partuuid(name);
 187                 if (!res)
 188                         goto fail;
 189                 goto done;
 190         }
 191 #endif
 192
 193         if (strncmp(name, "/dev/", 5) != 0) {
 194                 unsigned maj, min;
 195
 196                 if (sscanf(name, "%u:%u", &maj, &min) == 2) {
 197                         res = MKDEV(maj, min);
 198                         if (maj != MAJOR(res) || min != MINOR(res))
 199                                 goto fail;
 200                 } else {
 201                         res = new_decode_dev(simple_strtoul(name, &p, 16));
 202                         if (*p)
 203                                 goto fail;
 204                 }
 205                 goto done;
 206         }
 207
 208         name += 5;
 209         res = Root_NFS;
 210         if (strcmp(name, "nfs") == 0)
 211                 goto done;
 212         res = Root_RAM0;
 213         if (strcmp(name, "ram") == 0)
 214                 goto done;
 215
 216         if (strlen(name) > 31)
 217                 goto fail;
 218         strcpy(s, name);
 219         for (p = s; *p; p++)
 220                 if (*p == '/')
 221                         *p = '!';
 222         res = blk_lookup_devt(s, 0);
 223         if (res)
 224                 goto done;
 225
 226         /*
 227          * try non-existent, but valid partition, which may only exist
 228          * after revalidating the disk, like partitioned md devices
 229          */
 230         while (p > s && isdigit(p[-1]))
 231                 p--;
 232         if (p == s || !*p || *p == '0')
 233                 goto fail;
 234
 235         /* try disk name without <part number> */
 236         part = simple_strtoul(p, NULL, 10);
 237         *p = '\0';
 238         res = blk_lookup_devt(s, part);
 239         if (res)
 240                 goto done;
 241
 242         /* try disk name without p<part number> */
 243         if (p < s + 2 || !isdigit(p[-2]) || p[-1] != 'p')
 244                 goto fail;
 245         p[-1] = '\0';
 246         res = blk_lookup_devt(s, part);
 247         if (res)
 248                 goto done;
 249
 250 fail:
 251         return 0;
 252 done:
 253         return res;
 254 }
 255
 256 static int __init root_dev_setup(char *line)
 257 {
 258         strlcpy(saved_root_name, line, sizeof(saved_root_name));
 259         return 1;
 260 }
 261
 262 __setup("root=", root_dev_setup);
 263
 264 static int __init rootwait_setup(char *str)
 265 {
 266         if (*str)
 267                 return 0;
 268         root_wait = 1;
 269         return 1;
 270 }
 271
 272 __setup("rootwait", rootwait_setup);
 273
 274 static char * __initdata root_mount_data;
 275 static int __init root_data_setup(char *str)
 276 {
 277         root_mount_data = str;
 278         return 1;
 279 }
 280
 281 static char * __initdata root_fs_names;
 282 static int __init fs_names_setup(char *str)
 283 {
 284         root_fs_names = str;
 285         return 1;
 286 }
 287
 288 static unsigned int __initdata root_delay;
 289 static int __init root_delay_setup(char *str)
 290 {
 291         root_delay = simple_strtoul(str, NULL, 0);
 292         return 1;
 293 }
 294
 295 __setup("rootflags=", root_data_setup);
 296 __setup("rootfstype=", fs_names_setup);
 297 __setup("rootdelay=", root_delay_setup);
 298
 299 static void __init get_fs_names(char *page)
 300 {
 301         char *s = page;
 302
 303         if (root_fs_names) {
 304                 strcpy(page, root_fs_names);
 305                 while (*s++) {
 306                         if (s[-1] == ',')
 307                                 s[-1] = '\0';
 308                 }
 309         } else {
 310                 int len = get_filesystem_list(page);
 311                 char *p, *next;
 312
 313                 page[len] = '\0';
 314                 for (p = page-1; p; p = next) {
 315                         next = strchr(++p, '\n');
 316                         if (*p++ != '\t')
 317                                 continue;
 318                         while ((*s++ = *p++) != '\n')
 319                                 ;
 320                         s[-1] = '\0';
 321                 }
 322         }
 323         *s = '\0';
 324 }
 325
 326 static int __init do_mount_root(char *name, char *fs, int flags, void *data)
 327 {
 328         int err = sys_mount(name, "/root", fs, flags, data);
 329         if (err)
 330                 return err;
 331
 332         sys_chdir((const char __user __force *)"/root");
 333         ROOT_DEV = current->fs->pwd.mnt->mnt_sb->s_dev;
 334         printk(KERN_INFO
 335                "VFS: Mounted root (%s filesystem)%s on device %u:%u.\n",
 336                current->fs->pwd.mnt->mnt_sb->s_type->name,
 337                current->fs->pwd.mnt->mnt_sb->s_flags & MS_RDONLY ?
 338                " readonly" : "", MAJOR(ROOT_DEV), MINOR(ROOT_DEV));
 339         return 0;
 340 }
 341
 342 void __init mount_block_root(char *name, int flags)
 343 {
 344         char *fs_names = __getname_gfp(GFP_KERNEL
 345                 | __GFP_NOTRACK_FALSE_POSITIVE);
 346         char *p;
 347 #ifdef CONFIG_BLOCK
 348         char b[BDEVNAME_SIZE];
 349 #else
 350         const char *b = name;
 351 #endif
 352
 353         get_fs_names(fs_names);
 354 retry:
 355         for (p = fs_names; *p; p += strlen(p)+1) {
 356                 int err = do_mount_root(name, p, flags, root_mount_data);
 357                 switch (err) {
 358                         case 0:
 359                                 goto out;
 360                         case -EACCES:
 361                                 flags |= MS_RDONLY;
 362                                 goto retry;
 363                         case -EINVAL:
 364                                 continue;
 365                 }
 366                 /*
 367                  * Allow the user to distinguish between failed sys_open
 368                  * and bad superblock on root device.
 369                  * and give them a list of the available devices
 370                  */
 371 #ifdef CONFIG_BLOCK
 372                 __bdevname(ROOT_DEV, b);
 373 #endif
 374                 printk("VFS: Cannot open root device \"%s\" or %s\n",
 375                                 root_device_name, b);
 376                 printk("Please append a correct \"root=\" boot option; here are the available partitions:\n");
 377
 378                 printk_all_partitions();
 379 #ifdef CONFIG_DEBUG_BLOCK_EXT_DEVT
 380                 printk("DEBUG_BLOCK_EXT_DEVT is enabled, you need to specify "
 381                        "explicit textual name for \"root=\" boot option.\n");
 382 #endif
 383                 panic("VFS: Unable to mount root fs on %s", b);
 384         }
 385
 386         printk("List of all partitions:\n");
 387         printk_all_partitions();
 388         printk("No filesystem could mount root, tried: ");
 389         for (p = fs_names; *p; p += strlen(p)+1)
 390                 printk(" %s", p);
 391         printk("\n");
 392 #ifdef CONFIG_BLOCK
 393         __bdevname(ROOT_DEV, b);
 394 #endif
 395         panic("VFS: Unable to mount root fs on %s", b);
 396 out:
 397         putname(fs_names);
 398 }
 399
 400 #ifdef CONFIG_ROOT_NFS
 401
 402 #define NFSROOT_TIMEOUT_MIN     5
 403 #define NFSROOT_TIMEOUT_MAX     30
 404 #define NFSROOT_RETRY_MAX       5
 405
 406 static int __init mount_nfs_root(void)
 407 {
 408         char *root_dev, *root_data;
 409         unsigned int timeout;
 410         int try, err;
 411
 412         err = nfs_root_data(&root_dev, &root_data);
 413         if (err != 0)
 414                 return 0;
 415
 416         /*
 417          * The server or network may not be ready, so try several
 418          * times.  Stop after a few tries in case the client wants
 419          * to fall back to other boot methods.
 420          */
 421         timeout = NFSROOT_TIMEOUT_MIN;
 422         for (try = 1; ; try++) {
 423                 err = do_mount_root(root_dev, "nfs",
 424                                         root_mountflags, root_data);
 425                 if (err == 0)
 426                         return 1;
 427                 if (try > NFSROOT_RETRY_MAX)
 428                         break;
 429
 430                 /* Wait, in case the server refused us immediately */
 431                 ssleep(timeout);
 432                 timeout <<= 1;
 433                 if (timeout > NFSROOT_TIMEOUT_MAX)
 434                         timeout = NFSROOT_TIMEOUT_MAX;
 435         }
 436         return 0;
 437 }
 438 #endif
 439
 440 #if defined(CONFIG_BLK_DEV_RAM) || defined(CONFIG_BLK_DEV_FD)
 441 void __init change_floppy(char *fmt, ...)
 442 {
 443         struct termios termios;
 444         char buf[80];
 445         char c;
 446         int fd;
 447         va_list args;
 448         va_start(args, fmt);
 449         vsprintf(buf, fmt, args);
 450         va_end(args);
 451         fd = sys_open("/dev/root", O_RDWR | O_NDELAY, 0);
 452         if (fd >= 0) {
 453                 sys_ioctl(fd, FDEJECT, 0);
 454                 sys_close(fd);
 455         }
 456         printk(KERN_NOTICE "VFS: Insert %s and press ENTER\n", buf);
 457         fd = sys_open("/dev/console", O_RDWR, 0);
 458         if (fd >= 0) {
 459                 sys_ioctl(fd, TCGETS, (long)&termios);
 460                 termios.c_lflag &= ~ICANON;
 461                 sys_ioctl(fd, TCSETSF, (long)&termios);
 462                 sys_read(fd, &c, 1);
 463                 termios.c_lflag |= ICANON;
 464                 sys_ioctl(fd, TCSETSF, (long)&termios);
 465                 sys_close(fd);
 466         }
 467 }
 468 #endif
 469
 470 void __init mount_root(void)
 471 {
 472 #ifdef CONFIG_ROOT_NFS
 473         if (ROOT_DEV == Root_NFS) {
 474                 if (mount_nfs_root())
 475                         return;
 476
 477                 printk(KERN_ERR "VFS: Unable to mount root fs via NFS, trying floppy.\n");
 478                 ROOT_DEV = Root_FD0;
 479         }
 480 #endif
 481 #ifdef CONFIG_BLK_DEV_FD
 482         if (MAJOR(ROOT_DEV) == FLOPPY_MAJOR) {
 483                 /* rd_doload is 2 for a dual initrd/ramload setup */
 484                 if (rd_doload==2) {
 485                         if (rd_load_disk(1)) {
 486                                 ROOT_DEV = Root_RAM1;
 487                                 root_device_name = NULL;
 488                         }
 489                 } else
 490                         change_floppy("root floppy");
 491         }
 492 #endif
 493 #ifdef CONFIG_BLOCK
 494         create_dev("/dev/root", ROOT_DEV);
 495         mount_block_root("/dev/root", root_mountflags);
 496 #endif
 497 }
 498
 499 /*
 500  * Prepare the namespace - decide what/where to mount, load ramdisks, etc.
 501  */
 502 void __init prepare_namespace(void)
 503 {
 504         int is_floppy;
 505
 506         if (root_delay) {
 507                 printk(KERN_INFO "Waiting %dsec before mounting root device...\n",
 508                        root_delay);
 509                 ssleep(root_delay);
 510         }
 511
 512         /*
 513          * wait for the known devices to complete their probing
 514          *
 515          * Note: this is a potential source of long boot delays.
 516          * For example, it is not atypical to wait 5 seconds here
 517          * for the touchpad of a laptop to initialize.
 518          */
 519         wait_for_device_probe();
 520
 521         md_run_setup();
 522
 523         if (saved_root_name[0]) {
 524                 root_device_name = saved_root_name;
 525                 if (!strncmp(root_device_name, "mtd", 3) ||
 526                     !strncmp(root_device_name, "ubi", 3)) {
 527                         mount_block_root(root_device_name, root_mountflags);
 528                         goto out;
 529                 }
 530                 ROOT_DEV = name_to_dev_t(root_device_name);
 531                 if (strncmp(root_device_name, "/dev/", 5) == 0)
 532                         root_device_name += 5;
 533         }
 534
 535         if (initrd_load())
 536                 goto out;
 537
 538         /* wait for any asynchronous scanning to complete */
 539         if ((ROOT_DEV == 0) && root_wait) {
 540                 printk(KERN_INFO "Waiting for root device %s...\n",
 541                         saved_root_name);
 542                 while (driver_probe_done() != 0 ||
 543                         (ROOT_DEV = name_to_dev_t(saved_root_name)) == 0)
 544                         msleep(100);
 545                 async_synchronize_full();
 546         }
 547
 548         is_floppy = MAJOR(ROOT_DEV) == FLOPPY_MAJOR;
 549
 550         if (is_floppy && rd_doload && rd_load_disk(0))
 551                 ROOT_DEV = Root_RAM0;
 552
 553         mount_root();
 554 out:
 555         devtmpfs_mount("dev");
 556         sys_mount(".", "/", NULL, MS_MOVE, NULL);
 557         sys_chroot((const char __user __force *)".");
 558 }