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
  72struct 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 */
  84static 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;
  96no_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 */
 114static 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
 166no_offset:
 167        put_device(dev);
 168done:
 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
 205dev_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
 279fail:
 280        return 0;
 281done:
 282        return res;
 283}
 284
 285static 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
 293static 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
 303static char * __initdata root_mount_data;
 304static int __init root_data_setup(char *str)
 305{
 306        root_mount_data = str;
 307        return 1;
 308}
 309
 310static char * __initdata root_fs_names;
 311static int __init fs_names_setup(char *str)
 312{
 313        root_fs_names = str;
 314        return 1;
 315}
 316
 317static unsigned int __initdata root_delay;
 318static 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
 328static 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
 355static 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
 373void __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);
 386retry:
 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);
 428out:
 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
 438static 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)
 473void __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
 502void __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 */
 534void __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();
 586out:
 587        devtmpfs_mount("dev");
 588        sys_mount(".", "/", NULL, MS_MOVE, NULL);
 589        sys_chroot(".");
 590}
 591
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