linux/init/do_mounts.c
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   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
  26int __initdata rd_doload;       /* 1 = load RAM disk, 0 = don't load */
  27
  28int root_mountflags = MS_RDONLY | MS_SILENT;
  29static char * __initdata root_device_name;
  30static char __initdata saved_root_name[64];
  31static int __initdata root_wait;
  32
  33dev_t ROOT_DEV;
  34
  35static 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
  42static int __init readonly(char *str)
  43{
  44        if (*str)
  45                return 0;
  46        root_mountflags |= MS_RDONLY;
  47        return 1;
  48}
  49
  50static 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 */
  69static 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;
  81no_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 */
  96static 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
 112done:
 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
 136dev_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
 212fail:
 213        return 0;
 214done:
 215        return res;
 216}
 217
 218static 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
 226static 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
 236static char * __initdata root_mount_data;
 237static int __init root_data_setup(char *str)
 238{
 239        root_mount_data = str;
 240        return 1;
 241}
 242
 243static char * __initdata root_fs_names;
 244static int __init fs_names_setup(char *str)
 245{
 246        root_fs_names = str;
 247        return 1;
 248}
 249
 250static unsigned int __initdata root_delay;
 251static 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
 261static 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
 288static 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
 304void __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);
 316retry:
 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);
 358out:
 359        putname(fs_names);
 360}
 361 
 362#ifdef CONFIG_ROOT_NFS
 363static int __init mount_nfs_root(void)
 364{
 365        char *root_dev, *root_data;
 366
 367        if (nfs_root_data(&root_dev, &root_data) != 0)
 368                return 0;
 369        if (do_mount_root(root_dev, "nfs", root_mountflags, root_data) != 0)
 370                return 0;
 371        return 1;
 372}
 373#endif
 374
 375#if defined(CONFIG_BLK_DEV_RAM) || defined(CONFIG_BLK_DEV_FD)
 376void __init change_floppy(char *fmt, ...)
 377{
 378        struct termios termios;
 379        char buf[80];
 380        char c;
 381        int fd;
 382        va_list args;
 383        va_start(args, fmt);
 384        vsprintf(buf, fmt, args);
 385        va_end(args);
 386        fd = sys_open("/dev/root", O_RDWR | O_NDELAY, 0);
 387        if (fd >= 0) {
 388                sys_ioctl(fd, FDEJECT, 0);
 389                sys_close(fd);
 390        }
 391        printk(KERN_NOTICE "VFS: Insert %s and press ENTER\n", buf);
 392        fd = sys_open("/dev/console", O_RDWR, 0);
 393        if (fd >= 0) {
 394                sys_ioctl(fd, TCGETS, (long)&termios);
 395                termios.c_lflag &= ~ICANON;
 396                sys_ioctl(fd, TCSETSF, (long)&termios);
 397                sys_read(fd, &c, 1);
 398                termios.c_lflag |= ICANON;
 399                sys_ioctl(fd, TCSETSF, (long)&termios);
 400                sys_close(fd);
 401        }
 402}
 403#endif
 404
 405void __init mount_root(void)
 406{
 407#ifdef CONFIG_ROOT_NFS
 408        if (MAJOR(ROOT_DEV) == UNNAMED_MAJOR) {
 409                if (mount_nfs_root())
 410                        return;
 411
 412                printk(KERN_ERR "VFS: Unable to mount root fs via NFS, trying floppy.\n");
 413                ROOT_DEV = Root_FD0;
 414        }
 415#endif
 416#ifdef CONFIG_BLK_DEV_FD
 417        if (MAJOR(ROOT_DEV) == FLOPPY_MAJOR) {
 418                /* rd_doload is 2 for a dual initrd/ramload setup */
 419                if (rd_doload==2) {
 420                        if (rd_load_disk(1)) {
 421                                ROOT_DEV = Root_RAM1;
 422                                root_device_name = NULL;
 423                        }
 424                } else
 425                        change_floppy("root floppy");
 426        }
 427#endif
 428#ifdef CONFIG_BLOCK
 429        create_dev("/dev/root", ROOT_DEV);
 430        mount_block_root("/dev/root", root_mountflags);
 431#endif
 432}
 433
 434/*
 435 * Prepare the namespace - decide what/where to mount, load ramdisks, etc.
 436 */
 437void __init prepare_namespace(void)
 438{
 439        int is_floppy;
 440
 441        if (root_delay) {
 442                printk(KERN_INFO "Waiting %dsec before mounting root device...\n",
 443                       root_delay);
 444                ssleep(root_delay);
 445        }
 446
 447        /*
 448         * wait for the known devices to complete their probing
 449         *
 450         * Note: this is a potential source of long boot delays.
 451         * For example, it is not atypical to wait 5 seconds here
 452         * for the touchpad of a laptop to initialize.
 453         */
 454        wait_for_device_probe();
 455
 456        md_run_setup();
 457
 458        if (saved_root_name[0]) {
 459                root_device_name = saved_root_name;
 460                if (!strncmp(root_device_name, "mtd", 3) ||
 461                    !strncmp(root_device_name, "ubi", 3)) {
 462                        mount_block_root(root_device_name, root_mountflags);
 463                        goto out;
 464                }
 465                ROOT_DEV = name_to_dev_t(root_device_name);
 466                if (strncmp(root_device_name, "/dev/", 5) == 0)
 467                        root_device_name += 5;
 468        }
 469
 470        if (initrd_load())
 471                goto out;
 472
 473        /* wait for any asynchronous scanning to complete */
 474        if ((ROOT_DEV == 0) && root_wait) {
 475                printk(KERN_INFO "Waiting for root device %s...\n",
 476                        saved_root_name);
 477                while (driver_probe_done() != 0 ||
 478                        (ROOT_DEV = name_to_dev_t(saved_root_name)) == 0)
 479                        msleep(100);
 480                async_synchronize_full();
 481        }
 482
 483        is_floppy = MAJOR(ROOT_DEV) == FLOPPY_MAJOR;
 484
 485        if (is_floppy && rd_doload && rd_load_disk(0))
 486                ROOT_DEV = Root_RAM0;
 487
 488        mount_root();
 489out:
 490        devtmpfs_mount("dev");
 491        sys_mount(".", "/", NULL, MS_MOVE, NULL);
 492        sys_chroot((const char __user __force *)".");
 493}
 494
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