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