init/do_mounts.c

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