linux/init/do_mounts.c
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   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
  36int __initdata rd_doload;       /* 1 = load RAM disk, 0 = don't load */
  37
  38int root_mountflags = MS_RDONLY | MS_SILENT;
  39static char * __initdata root_device_name;
  40static char __initdata saved_root_name[64];
  41static int root_wait;
  42
  43dev_t ROOT_DEV;
  44
  45static 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
  52static int __init readonly(char *str)
  53{
  54        if (*str)
  55                return 0;
  56        root_mountflags |= MS_RDONLY;
  57        return 1;
  58}
  59
  60static 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/**
  73 * match_dev_by_uuid - callback for finding a partition using its uuid
  74 * @dev:        device passed in by the caller
  75 * @data:       opaque pointer to a 36 byte char array with a UUID
  76 *
  77 * Returns 1 if the device matches, and 0 otherwise.
  78 */
  79static int match_dev_by_uuid(struct device *dev, void *data)
  80{
  81        u8 *uuid = data;
  82        struct hd_struct *part = dev_to_part(dev);
  83
  84        if (!part->info)
  85                goto no_match;
  86
  87        if (memcmp(uuid, part->info->uuid, sizeof(part->info->uuid)))
  88                        goto no_match;
  89
  90        return 1;
  91no_match:
  92        return 0;
  93}
  94
  95
  96/**
  97 * devt_from_partuuid - looks up the dev_t of a partition by its UUID
  98 * @uuid:       min 36 byte char array containing a hex ascii UUID
  99 *
 100 * The function will return the first partition which contains a matching
 101 * UUID value in its partition_meta_info struct.  This does not search
 102 * by filesystem UUIDs.
 103 *
 104 * If @uuid is followed by a "/PARTNROFF=%d", then the number will be
 105 * extracted and used as an offset from the partition identified by the UUID.
 106 *
 107 * Returns the matching dev_t on success or 0 on failure.
 108 */
 109static dev_t devt_from_partuuid(char *uuid_str)
 110{
 111        dev_t res = 0;
 112        struct device *dev = NULL;
 113        u8 uuid[16];
 114        struct gendisk *disk;
 115        struct hd_struct *part;
 116        int offset = 0;
 117
 118        if (strlen(uuid_str) < 36)
 119                goto done;
 120
 121        /* Check for optional partition number offset attributes. */
 122        if (uuid_str[36]) {
 123                char c = 0;
 124                /* Explicitly fail on poor PARTUUID syntax. */
 125                if (sscanf(&uuid_str[36],
 126                           "/PARTNROFF=%d%c", &offset, &c) != 1) {
 127                        printk(KERN_ERR "VFS: PARTUUID= is invalid.\n"
 128                         "Expected PARTUUID=<valid-uuid-id>[/PARTNROFF=%%d]\n");
 129                        if (root_wait)
 130                                printk(KERN_ERR
 131                                     "Disabling rootwait; root= is invalid.\n");
 132                        root_wait = 0;
 133                        goto done;
 134                }
 135        }
 136
 137        /* Pack the requested UUID in the expected format. */
 138        part_pack_uuid(uuid_str, uuid);
 139
 140        dev = class_find_device(&block_class, NULL, uuid, &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
 158no_offset:
 159        put_device(dev);
 160done:
 161        return res;
 162}
 163#endif
 164
 165/*
 166 *      Convert a name into device number.  We accept the following variants:
 167 *
 168 *      1) device number in hexadecimal represents itself
 169 *      2) /dev/nfs represents Root_NFS (0xff)
 170 *      3) /dev/<disk_name> represents the device number of disk
 171 *      4) /dev/<disk_name><decimal> represents the device number
 172 *         of partition - device number of disk plus the partition number
 173 *      5) /dev/<disk_name>p<decimal> - same as the above, that form is
 174 *         used when disk name of partitioned disk ends on a digit.
 175 *      6) PARTUUID=00112233-4455-6677-8899-AABBCCDDEEFF representing the
 176 *         unique id of a partition if the partition table provides it.
 177 *      7) PARTUUID=<UUID>/PARTNROFF=<int> to select a partition in relation to
 178 *         a partition with a known unique id.
 179 *
 180 *      If name doesn't have fall into the categories above, we return (0,0).
 181 *      block_class is used to check if something is a disk name. If the disk
 182 *      name contains slashes, the device name has them replaced with
 183 *      bangs.
 184 */
 185
 186dev_t name_to_dev_t(char *name)
 187{
 188        char s[32];
 189        char *p;
 190        dev_t res = 0;
 191        int part;
 192
 193#ifdef CONFIG_BLOCK
 194        if (strncmp(name, "PARTUUID=", 9) == 0) {
 195                name += 9;
 196                res = devt_from_partuuid(name);
 197                if (!res)
 198                        goto fail;
 199                goto done;
 200        }
 201#endif
 202
 203        if (strncmp(name, "/dev/", 5) != 0) {
 204                unsigned maj, min;
 205
 206                if (sscanf(name, "%u:%u", &maj, &min) == 2) {
 207                        res = MKDEV(maj, min);
 208                        if (maj != MAJOR(res) || min != MINOR(res))
 209                                goto fail;
 210                } else {
 211                        res = new_decode_dev(simple_strtoul(name, &p, 16));
 212                        if (*p)
 213                                goto fail;
 214                }
 215                goto done;
 216        }
 217
 218        name += 5;
 219        res = Root_NFS;
 220        if (strcmp(name, "nfs") == 0)
 221                goto done;
 222        res = Root_RAM0;
 223        if (strcmp(name, "ram") == 0)
 224                goto done;
 225
 226        if (strlen(name) > 31)
 227                goto fail;
 228        strcpy(s, name);
 229        for (p = s; *p; p++)
 230                if (*p == '/')
 231                        *p = '!';
 232        res = blk_lookup_devt(s, 0);
 233        if (res)
 234                goto done;
 235
 236        /*
 237         * try non-existent, but valid partition, which may only exist
 238         * after revalidating the disk, like partitioned md devices
 239         */
 240        while (p > s && isdigit(p[-1]))
 241                p--;
 242        if (p == s || !*p || *p == '0')
 243                goto fail;
 244
 245        /* try disk name without <part number> */
 246        part = simple_strtoul(p, NULL, 10);
 247        *p = '\0';
 248        res = blk_lookup_devt(s, part);
 249        if (res)
 250                goto done;
 251
 252        /* try disk name without p<part number> */
 253        if (p < s + 2 || !isdigit(p[-2]) || p[-1] != 'p')
 254                goto fail;
 255        p[-1] = '\0';
 256        res = blk_lookup_devt(s, part);
 257        if (res)
 258                goto done;
 259
 260fail:
 261        return 0;
 262done:
 263        return res;
 264}
 265
 266static int __init root_dev_setup(char *line)
 267{
 268        strlcpy(saved_root_name, line, sizeof(saved_root_name));
 269        return 1;
 270}
 271
 272__setup("root=", root_dev_setup);
 273
 274static int __init rootwait_setup(char *str)
 275{
 276        if (*str)
 277                return 0;
 278        root_wait = 1;
 279        return 1;
 280}
 281
 282__setup("rootwait", rootwait_setup);
 283
 284static char * __initdata root_mount_data;
 285static int __init root_data_setup(char *str)
 286{
 287        root_mount_data = str;
 288        return 1;
 289}
 290
 291static char * __initdata root_fs_names;
 292static int __init fs_names_setup(char *str)
 293{
 294        root_fs_names = str;
 295        return 1;
 296}
 297
 298static unsigned int __initdata root_delay;
 299static int __init root_delay_setup(char *str)
 300{
 301        root_delay = simple_strtoul(str, NULL, 0);
 302        return 1;
 303}
 304
 305__setup("rootflags=", root_data_setup);
 306__setup("rootfstype=", fs_names_setup);
 307__setup("rootdelay=", root_delay_setup);
 308
 309static void __init get_fs_names(char *page)
 310{
 311        char *s = page;
 312
 313        if (root_fs_names) {
 314                strcpy(page, root_fs_names);
 315                while (*s++) {
 316                        if (s[-1] == ',')
 317                                s[-1] = '\0';
 318                }
 319        } else {
 320                int len = get_filesystem_list(page);
 321                char *p, *next;
 322
 323                page[len] = '\0';
 324                for (p = page-1; p; p = next) {
 325                        next = strchr(++p, '\n');
 326                        if (*p++ != '\t')
 327                                continue;
 328                        while ((*s++ = *p++) != '\n')
 329                                ;
 330                        s[-1] = '\0';
 331                }
 332        }
 333        *s = '\0';
 334}
 335
 336static int __init do_mount_root(char *name, char *fs, int flags, void *data)
 337{
 338        struct super_block *s;
 339        int err = sys_mount(name, "/root", fs, flags, data);
 340        if (err)
 341                return err;
 342
 343        sys_chdir("/root");
 344        s = current->fs->pwd.dentry->d_sb;
 345        ROOT_DEV = s->s_dev;
 346        printk(KERN_INFO
 347               "VFS: Mounted root (%s filesystem)%s on device %u:%u.\n",
 348               s->s_type->name,
 349               s->s_flags & MS_RDONLY ?  " readonly" : "",
 350               MAJOR(ROOT_DEV), MINOR(ROOT_DEV));
 351        return 0;
 352}
 353
 354void __init mount_block_root(char *name, int flags)
 355{
 356        struct page *page = alloc_page(GFP_KERNEL |
 357                                        __GFP_NOTRACK_FALSE_POSITIVE);
 358        char *fs_names = page_address(page);
 359        char *p;
 360#ifdef CONFIG_BLOCK
 361        char b[BDEVNAME_SIZE];
 362#else
 363        const char *b = name;
 364#endif
 365
 366        get_fs_names(fs_names);
 367retry:
 368        for (p = fs_names; *p; p += strlen(p)+1) {
 369                int err = do_mount_root(name, p, flags, root_mount_data);
 370                switch (err) {
 371                        case 0:
 372                                goto out;
 373                        case -EACCES:
 374                                flags |= MS_RDONLY;
 375                                goto retry;
 376                        case -EINVAL:
 377                                continue;
 378                }
 379                /*
 380                 * Allow the user to distinguish between failed sys_open
 381                 * and bad superblock on root device.
 382                 * and give them a list of the available devices
 383                 */
 384#ifdef CONFIG_BLOCK
 385                __bdevname(ROOT_DEV, b);
 386#endif
 387                printk("VFS: Cannot open root device \"%s\" or %s: error %d\n",
 388                                root_device_name, b, err);
 389                printk("Please append a correct \"root=\" boot option; here are the available partitions:\n");
 390
 391                printk_all_partitions();
 392#ifdef CONFIG_DEBUG_BLOCK_EXT_DEVT
 393                printk("DEBUG_BLOCK_EXT_DEVT is enabled, you need to specify "
 394                       "explicit textual name for \"root=\" boot option.\n");
 395#endif
 396                panic("VFS: Unable to mount root fs on %s", b);
 397        }
 398
 399        printk("List of all partitions:\n");
 400        printk_all_partitions();
 401        printk("No filesystem could mount root, tried: ");
 402        for (p = fs_names; *p; p += strlen(p)+1)
 403                printk(" %s", p);
 404        printk("\n");
 405#ifdef CONFIG_BLOCK
 406        __bdevname(ROOT_DEV, b);
 407#endif
 408        panic("VFS: Unable to mount root fs on %s", b);
 409out:
 410        put_page(page);
 411}
 412 
 413#ifdef CONFIG_ROOT_NFS
 414
 415#define NFSROOT_TIMEOUT_MIN     5
 416#define NFSROOT_TIMEOUT_MAX     30
 417#define NFSROOT_RETRY_MAX       5
 418
 419static int __init mount_nfs_root(void)
 420{
 421        char *root_dev, *root_data;
 422        unsigned int timeout;
 423        int try, err;
 424
 425        err = nfs_root_data(&root_dev, &root_data);
 426        if (err != 0)
 427                return 0;
 428
 429        /*
 430         * The server or network may not be ready, so try several
 431         * times.  Stop after a few tries in case the client wants
 432         * to fall back to other boot methods.
 433         */
 434        timeout = NFSROOT_TIMEOUT_MIN;
 435        for (try = 1; ; try++) {
 436                err = do_mount_root(root_dev, "nfs",
 437                                        root_mountflags, root_data);
 438                if (err == 0)
 439                        return 1;
 440                if (try > NFSROOT_RETRY_MAX)
 441                        break;
 442
 443                /* Wait, in case the server refused us immediately */
 444                ssleep(timeout);
 445                timeout <<= 1;
 446                if (timeout > NFSROOT_TIMEOUT_MAX)
 447                        timeout = NFSROOT_TIMEOUT_MAX;
 448        }
 449        return 0;
 450}
 451#endif
 452
 453#if defined(CONFIG_BLK_DEV_RAM) || defined(CONFIG_BLK_DEV_FD)
 454void __init change_floppy(char *fmt, ...)
 455{
 456        struct termios termios;
 457        char buf[80];
 458        char c;
 459        int fd;
 460        va_list args;
 461        va_start(args, fmt);
 462        vsprintf(buf, fmt, args);
 463        va_end(args);
 464        fd = sys_open("/dev/root", O_RDWR | O_NDELAY, 0);
 465        if (fd >= 0) {
 466                sys_ioctl(fd, FDEJECT, 0);
 467                sys_close(fd);
 468        }
 469        printk(KERN_NOTICE "VFS: Insert %s and press ENTER\n", buf);
 470        fd = sys_open("/dev/console", O_RDWR, 0);
 471        if (fd >= 0) {
 472                sys_ioctl(fd, TCGETS, (long)&termios);
 473                termios.c_lflag &= ~ICANON;
 474                sys_ioctl(fd, TCSETSF, (long)&termios);
 475                sys_read(fd, &c, 1);
 476                termios.c_lflag |= ICANON;
 477                sys_ioctl(fd, TCSETSF, (long)&termios);
 478                sys_close(fd);
 479        }
 480}
 481#endif
 482
 483void __init mount_root(void)
 484{
 485#ifdef CONFIG_ROOT_NFS
 486        if (ROOT_DEV == Root_NFS) {
 487                if (mount_nfs_root())
 488                        return;
 489
 490                printk(KERN_ERR "VFS: Unable to mount root fs via NFS, trying floppy.\n");
 491                ROOT_DEV = Root_FD0;
 492        }
 493#endif
 494#ifdef CONFIG_BLK_DEV_FD
 495        if (MAJOR(ROOT_DEV) == FLOPPY_MAJOR) {
 496                /* rd_doload is 2 for a dual initrd/ramload setup */
 497                if (rd_doload==2) {
 498                        if (rd_load_disk(1)) {
 499                                ROOT_DEV = Root_RAM1;
 500                                root_device_name = NULL;
 501                        }
 502                } else
 503                        change_floppy("root floppy");
 504        }
 505#endif
 506#ifdef CONFIG_BLOCK
 507        create_dev("/dev/root", ROOT_DEV);
 508        mount_block_root("/dev/root", root_mountflags);
 509#endif
 510}
 511
 512/*
 513 * Prepare the namespace - decide what/where to mount, load ramdisks, etc.
 514 */
 515void __init prepare_namespace(void)
 516{
 517        int is_floppy;
 518
 519        if (root_delay) {
 520                printk(KERN_INFO "Waiting %dsec before mounting root device...\n",
 521                       root_delay);
 522                ssleep(root_delay);
 523        }
 524
 525        /*
 526         * wait for the known devices to complete their probing
 527         *
 528         * Note: this is a potential source of long boot delays.
 529         * For example, it is not atypical to wait 5 seconds here
 530         * for the touchpad of a laptop to initialize.
 531         */
 532        wait_for_device_probe();
 533
 534        md_run_setup();
 535
 536        if (saved_root_name[0]) {
 537                root_device_name = saved_root_name;
 538                if (!strncmp(root_device_name, "mtd", 3) ||
 539                    !strncmp(root_device_name, "ubi", 3)) {
 540                        mount_block_root(root_device_name, root_mountflags);
 541                        goto out;
 542                }
 543                ROOT_DEV = name_to_dev_t(root_device_name);
 544                if (strncmp(root_device_name, "/dev/", 5) == 0)
 545                        root_device_name += 5;
 546        }
 547
 548        if (initrd_load())
 549                goto out;
 550
 551        /* wait for any asynchronous scanning to complete */
 552        if ((ROOT_DEV == 0) && root_wait) {
 553                printk(KERN_INFO "Waiting for root device %s...\n",
 554                        saved_root_name);
 555                while (driver_probe_done() != 0 ||
 556                        (ROOT_DEV = name_to_dev_t(saved_root_name)) == 0)
 557                        msleep(100);
 558                async_synchronize_full();
 559        }
 560
 561        is_floppy = MAJOR(ROOT_DEV) == FLOPPY_MAJOR;
 562
 563        if (is_floppy && rd_doload && rd_load_disk(0))
 564                ROOT_DEV = Root_RAM0;
 565
 566        mount_root();
 567out:
 568        devtmpfs_mount("dev");
 569        sys_mount(".", "/", NULL, MS_MOVE, NULL);
 570        sys_chroot(".");
 571}
 572
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