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 EXPORT_SYMBOL_GPL(name_to_dev_t);
 285
 286 static int __init root_dev_setup(char *line)
 287 {
 288         strlcpy(saved_root_name, line, sizeof(saved_root_name));
 289         return 1;
 290 }
 291
 292 __setup("root=", root_dev_setup);
 293
 294 static int __init rootwait_setup(char *str)
 295 {
 296         if (*str)
 297                 return 0;
 298         root_wait = 1;
 299         return 1;
 300 }
 301
 302 __setup("rootwait", rootwait_setup);
 303
 304 static char * __initdata root_mount_data;
 305 static int __init root_data_setup(char *str)
 306 {
 307         root_mount_data = str;
 308         return 1;
 309 }
 310
 311 static char * __initdata root_fs_names;
 312 static int __init fs_names_setup(char *str)
 313 {
 314         root_fs_names = str;
 315         return 1;
 316 }
 317
 318 static unsigned int __initdata root_delay;
 319 static int __init root_delay_setup(char *str)
 320 {
 321         root_delay = simple_strtoul(str, NULL, 0);
 322         return 1;
 323 }
 324
 325 __setup("rootflags=", root_data_setup);
 326 __setup("rootfstype=", fs_names_setup);
 327 __setup("rootdelay=", root_delay_setup);
 328
 329 static void __init get_fs_names(char *page)
 330 {
 331         char *s = page;
 332
 333         if (root_fs_names) {
 334                 strcpy(page, root_fs_names);
 335                 while (*s++) {
 336                         if (s[-1] == ',')
 337                                 s[-1] = '\0';
 338                 }
 339         } else {
 340                 int len = get_filesystem_list(page);
 341                 char *p, *next;
 342
 343                 page[len] = '\0';
 344                 for (p = page-1; p; p = next) {
 345                         next = strchr(++p, '\n');
 346                         if (*p++ != '\t')
 347                                 continue;
 348                         while ((*s++ = *p++) != '\n')
 349                                 ;
 350                         s[-1] = '\0';
 351                 }
 352         }
 353         *s = '\0';
 354 }
 355
 356 static int __init do_mount_root(char *name, char *fs, int flags, void *data)
 357 {
 358         struct super_block *s;
 359         int err = sys_mount(name, "/root", fs, flags, data);
 360         if (err)
 361                 return err;
 362
 363         sys_chdir("/root");
 364         s = current->fs->pwd.dentry->d_sb;
 365         ROOT_DEV = s->s_dev;
 366         printk(KERN_INFO
 367                "VFS: Mounted root (%s filesystem)%s on device %u:%u.\n",
 368                s->s_type->name,
 369                s->s_flags & MS_RDONLY ?  " readonly" : "",
 370                MAJOR(ROOT_DEV), MINOR(ROOT_DEV));
 371         return 0;
 372 }
 373
 374 void __init mount_block_root(char *name, int flags)
 375 {
 376         struct page *page = alloc_page(GFP_KERNEL |
 377                                         __GFP_NOTRACK_FALSE_POSITIVE);
 378         char *fs_names = page_address(page);
 379         char *p;
 380 #ifdef CONFIG_BLOCK
 381         char b[BDEVNAME_SIZE];
 382 #else
 383         const char *b = name;
 384 #endif
 385
 386         get_fs_names(fs_names);
 387 retry:
 388         for (p = fs_names; *p; p += strlen(p)+1) {
 389                 int err = do_mount_root(name, p, flags, root_mount_data);
 390                 switch (err) {
 391                         case 0:
 392                                 goto out;
 393                         case -EACCES:
 394                                 flags |= MS_RDONLY;
 395                                 goto retry;
 396                         case -EINVAL:
 397                                 continue;
 398                 }
 399                 /*
 400                  * Allow the user to distinguish between failed sys_open
 401                  * and bad superblock on root device.
 402                  * and give them a list of the available devices
 403                  */
 404 #ifdef CONFIG_BLOCK
 405                 __bdevname(ROOT_DEV, b);
 406 #endif
 407                 printk("VFS: Cannot open root device \"%s\" or %s: error %d\n",
 408                                 root_device_name, b, err);
 409                 printk("Please append a correct \"root=\" boot option; here are the available partitions:\n");
 410
 411                 printk_all_partitions();
 412 #ifdef CONFIG_DEBUG_BLOCK_EXT_DEVT
 413                 printk("DEBUG_BLOCK_EXT_DEVT is enabled, you need to specify "
 414                        "explicit textual name for \"root=\" boot option.\n");
 415 #endif
 416                 panic("VFS: Unable to mount root fs on %s", b);
 417         }
 418
 419         printk("List of all partitions:\n");
 420         printk_all_partitions();
 421         printk("No filesystem could mount root, tried: ");
 422         for (p = fs_names; *p; p += strlen(p)+1)
 423                 printk(" %s", p);
 424         printk("\n");
 425 #ifdef CONFIG_BLOCK
 426         __bdevname(ROOT_DEV, b);
 427 #endif
 428         panic("VFS: Unable to mount root fs on %s", b);
 429 out:
 430         put_page(page);
 431 }
 432
 433 #ifdef CONFIG_ROOT_NFS
 434
 435 #define NFSROOT_TIMEOUT_MIN     5
 436 #define NFSROOT_TIMEOUT_MAX     30
 437 #define NFSROOT_RETRY_MAX       5
 438
 439 static int __init mount_nfs_root(void)
 440 {
 441         char *root_dev, *root_data;
 442         unsigned int timeout;
 443         int try, err;
 444
 445         err = nfs_root_data(&root_dev, &root_data);
 446         if (err != 0)
 447                 return 0;
 448
 449         /*
 450          * The server or network may not be ready, so try several
 451          * times.  Stop after a few tries in case the client wants
 452          * to fall back to other boot methods.
 453          */
 454         timeout = NFSROOT_TIMEOUT_MIN;
 455         for (try = 1; ; try++) {
 456                 err = do_mount_root(root_dev, "nfs",
 457                                         root_mountflags, root_data);
 458                 if (err == 0)
 459                         return 1;
 460                 if (try > NFSROOT_RETRY_MAX)
 461                         break;
 462
 463                 /* Wait, in case the server refused us immediately */
 464                 ssleep(timeout);
 465                 timeout <<= 1;
 466                 if (timeout > NFSROOT_TIMEOUT_MAX)
 467                         timeout = NFSROOT_TIMEOUT_MAX;
 468         }
 469         return 0;
 470 }
 471 #endif
 472
 473 #if defined(CONFIG_BLK_DEV_RAM) || defined(CONFIG_BLK_DEV_FD)
 474 void __init change_floppy(char *fmt, ...)
 475 {
 476         struct termios termios;
 477         char buf[80];
 478         char c;
 479         int fd;
 480         va_list args;
 481         va_start(args, fmt);
 482         vsprintf(buf, fmt, args);
 483         va_end(args);
 484         fd = sys_open("/dev/root", O_RDWR | O_NDELAY, 0);
 485         if (fd >= 0) {
 486                 sys_ioctl(fd, FDEJECT, 0);
 487                 sys_close(fd);
 488         }
 489         printk(KERN_NOTICE "VFS: Insert %s and press ENTER\n", buf);
 490         fd = sys_open("/dev/console", O_RDWR, 0);
 491         if (fd >= 0) {
 492                 sys_ioctl(fd, TCGETS, (long)&termios);
 493                 termios.c_lflag &= ~ICANON;
 494                 sys_ioctl(fd, TCSETSF, (long)&termios);
 495                 sys_read(fd, &c, 1);
 496                 termios.c_lflag |= ICANON;
 497                 sys_ioctl(fd, TCSETSF, (long)&termios);
 498                 sys_close(fd);
 499         }
 500 }
 501 #endif
 502
 503 void __init mount_root(void)
 504 {
 505 #ifdef CONFIG_ROOT_NFS
 506         if (ROOT_DEV == Root_NFS) {
 507                 if (mount_nfs_root())
 508                         return;
 509
 510                 printk(KERN_ERR "VFS: Unable to mount root fs via NFS, trying floppy.\n");
 511                 ROOT_DEV = Root_FD0;
 512         }
 513 #endif
 514 #ifdef CONFIG_BLK_DEV_FD
 515         if (MAJOR(ROOT_DEV) == FLOPPY_MAJOR) {
 516                 /* rd_doload is 2 for a dual initrd/ramload setup */
 517                 if (rd_doload==2) {
 518                         if (rd_load_disk(1)) {
 519                                 ROOT_DEV = Root_RAM1;
 520                                 root_device_name = NULL;
 521                         }
 522                 } else
 523                         change_floppy("root floppy");
 524         }
 525 #endif
 526 #ifdef CONFIG_BLOCK
 527         create_dev("/dev/root", ROOT_DEV);
 528         mount_block_root("/dev/root", root_mountflags);
 529 #endif
 530 }
 531
 532 /*
 533  * Prepare the namespace - decide what/where to mount, load ramdisks, etc.
 534  */
 535 void __init prepare_namespace(void)
 536 {
 537         int is_floppy;
 538
 539         if (root_delay) {
 540                 printk(KERN_INFO "Waiting %dsec before mounting root device...\n",
 541                        root_delay);
 542                 ssleep(root_delay);
 543         }
 544
 545         /*
 546          * wait for the known devices to complete their probing
 547          *
 548          * Note: this is a potential source of long boot delays.
 549          * For example, it is not atypical to wait 5 seconds here
 550          * for the touchpad of a laptop to initialize.
 551          */
 552         wait_for_device_probe();
 553
 554         md_run_setup();
 555
 556         if (saved_root_name[0]) {
 557                 root_device_name = saved_root_name;
 558                 if (!strncmp(root_device_name, "mtd", 3) ||
 559                     !strncmp(root_device_name, "ubi", 3)) {
 560                         mount_block_root(root_device_name, root_mountflags);
 561                         goto out;
 562                 }
 563                 ROOT_DEV = name_to_dev_t(root_device_name);
 564                 if (strncmp(root_device_name, "/dev/", 5) == 0)
 565                         root_device_name += 5;
 566         }
 567
 568         if (initrd_load())
 569                 goto out;
 570
 571         /* wait for any asynchronous scanning to complete */
 572         if ((ROOT_DEV == 0) && root_wait) {
 573                 printk(KERN_INFO "Waiting for root device %s...\n",
 574                         saved_root_name);
 575                 while (driver_probe_done() != 0 ||
 576                         (ROOT_DEV = name_to_dev_t(saved_root_name)) == 0)
 577                         msleep(100);
 578                 async_synchronize_full();
 579         }
 580
 581         is_floppy = MAJOR(ROOT_DEV) == FLOPPY_MAJOR;
 582
 583         if (is_floppy && rd_doload && rd_load_disk(0))
 584                 ROOT_DEV = Root_RAM0;
 585
 586         check_resume_attempted();
 587
 588         mount_root();
 589 out:
 590         devtmpfs_mount("dev");
 591         sys_mount(".", "/", NULL, MS_MOVE, NULL);
 592         sys_chroot(".");
 593 }