init/do_mounts.c

   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
  10 #include <linux/nfs_fs.h>
  11 #include <linux/nfs_fs_sb.h>
  12 #include <linux/nfs_mount.h>
  13
  14 #include "do_mounts.h"
  15
  16 extern int get_filesystem_list(char * buf);
  17
  18 int __initdata rd_doload;       /* 1 = load RAM disk, 0 = don't load */
  19
  20 int root_mountflags = MS_RDONLY | MS_VERBOSE;
  21 char * __initdata root_device_name;
  22 static char __initdata saved_root_name[64];
  23
  24 /* this is initialized in init/main.c */
  25 dev_t ROOT_DEV;
  26
  27 EXPORT_SYMBOL(ROOT_DEV);
  28
  29 static int __init load_ramdisk(char *str)
  30 {
  31         rd_doload = simple_strtol(str,NULL,0) & 3;
  32         return 1;
  33 }
  34 __setup("load_ramdisk=", load_ramdisk);
  35
  36 static int __init readonly(char *str)
  37 {
  38         if (*str)
  39                 return 0;
  40         root_mountflags |= MS_RDONLY;
  41         return 1;
  42 }
  43
  44 static int __init readwrite(char *str)
  45 {
  46         if (*str)
  47                 return 0;
  48         root_mountflags &= ~MS_RDONLY;
  49         return 1;
  50 }
  51
  52 __setup("ro", readonly);
  53 __setup("rw", readwrite);
  54
  55 static dev_t __init try_name(char *name, int part)
  56 {
  57         char path[64];
  58         char buf[32];
  59         int range;
  60         dev_t res;
  61         char *s;
  62         int len;
  63         int fd;
  64         unsigned int maj, min;
  65
  66         /* read device number from .../dev */
  67
  68         sprintf(path, "/sys/block/%s/dev", name);
  69         fd = sys_open(path, 0, 0);
  70         if (fd < 0)
  71                 goto fail;
  72         len = sys_read(fd, buf, 32);
  73         sys_close(fd);
  74         if (len <= 0 || len == 32 || buf[len - 1] != '\n')
  75                 goto fail;
  76         buf[len - 1] = '\0';
  77         if (sscanf(buf, "%u:%u", &maj, &min) == 2) {
  78                 /*
  79                  * Try the %u:%u format -- see print_dev_t()
  80                  */
  81                 res = MKDEV(maj, min);
  82                 if (maj != MAJOR(res) || min != MINOR(res))
  83                         goto fail;
  84         } else {
  85                 /*
  86                  * Nope.  Try old-style "0321"
  87                  */
  88                 res = new_decode_dev(simple_strtoul(buf, &s, 16));
  89                 if (*s)
  90                         goto fail;
  91         }
  92
  93         /* if it's there and we are not looking for a partition - that's it */
  94         if (!part)
  95                 return res;
  96
  97         /* otherwise read range from .../range */
  98         sprintf(path, "/sys/block/%s/range", name);
  99         fd = sys_open(path, 0, 0);
 100         if (fd < 0)
 101                 goto fail;
 102         len = sys_read(fd, buf, 32);
 103         sys_close(fd);
 104         if (len <= 0 || len == 32 || buf[len - 1] != '\n')
 105                 goto fail;
 106         buf[len - 1] = '\0';
 107         range = simple_strtoul(buf, &s, 10);
 108         if (*s)
 109                 goto fail;
 110
 111         /* if partition is within range - we got it */
 112         if (part < range)
 113                 return res + part;
 114 fail:
 115         return 0;
 116 }
 117
 118 /*
 119  *      Convert a name into device number.  We accept the following variants:
 120  *
 121  *      1) device number in hexadecimal represents itself
 122  *      2) /dev/nfs represents Root_NFS (0xff)
 123  *      3) /dev/<disk_name> represents the device number of disk
 124  *      4) /dev/<disk_name><decimal> represents the device number
 125  *         of partition - device number of disk plus the partition number
 126  *      5) /dev/<disk_name>p<decimal> - same as the above, that form is
 127  *         used when disk name of partitioned disk ends on a digit.
 128  *
 129  *      If name doesn't have fall into the categories above, we return 0.
 130  *      Driverfs is used to check if something is a disk name - it has
 131  *      all known disks under bus/block/devices.  If the disk name
 132  *      contains slashes, name of driverfs node has them replaced with
 133  *      bangs.  try_name() does the actual checks, assuming that driverfs
 134  *      is mounted on rootfs /sys.
 135  */
 136
 137 dev_t __init name_to_dev_t(char *name)
 138 {
 139         char s[32];
 140         char *p;
 141         dev_t res = 0;
 142         int part;
 143
 144 #ifdef CONFIG_SYSFS
 145         sys_mkdir("/sys", 0700);
 146         if (sys_mount("sysfs", "/sys", "sysfs", 0, NULL) < 0)
 147                 goto out;
 148 #endif
 149
 150         if (strncmp(name, "/dev/", 5) != 0) {
 151                 unsigned maj, min;
 152
 153                 if (sscanf(name, "%u:%u", &maj, &min) == 2) {
 154                         res = MKDEV(maj, min);
 155                         if (maj != MAJOR(res) || min != MINOR(res))
 156                                 goto fail;
 157                 } else {
 158                         res = new_decode_dev(simple_strtoul(name, &p, 16));
 159                         if (*p)
 160                                 goto fail;
 161                 }
 162                 goto done;
 163         }
 164         name += 5;
 165         res = Root_NFS;
 166         if (strcmp(name, "nfs") == 0)
 167                 goto done;
 168         res = Root_RAM0;
 169         if (strcmp(name, "ram") == 0)
 170                 goto done;
 171
 172         if (strlen(name) > 31)
 173                 goto fail;
 174         strcpy(s, name);
 175         for (p = s; *p; p++)
 176                 if (*p == '/')
 177                         *p = '!';
 178         res = try_name(s, 0);
 179         if (res)
 180                 goto done;
 181
 182         while (p > s && isdigit(p[-1]))
 183                 p--;
 184         if (p == s || !*p || *p == '0')
 185                 goto fail;
 186         part = simple_strtoul(p, NULL, 10);
 187         *p = '\0';
 188         res = try_name(s, part);
 189         if (res)
 190                 goto done;
 191
 192         if (p < s + 2 || !isdigit(p[-2]) || p[-1] != 'p')
 193                 goto fail;
 194         p[-1] = '\0';
 195         res = try_name(s, part);
 196 done:
 197 #ifdef CONFIG_SYSFS
 198         sys_umount("/sys", 0);
 199 out:
 200         sys_rmdir("/sys");
 201 #endif
 202         return res;
 203 fail:
 204         res = 0;
 205         goto done;
 206 }
 207
 208 static int __init root_dev_setup(char *line)
 209 {
 210         strlcpy(saved_root_name, line, sizeof(saved_root_name));
 211         return 1;
 212 }
 213
 214 __setup("root=", root_dev_setup);
 215
 216 static char * __initdata root_mount_data;
 217 static int __init root_data_setup(char *str)
 218 {
 219         root_mount_data = str;
 220         return 1;
 221 }
 222
 223 static char * __initdata root_fs_names;
 224 static int __init fs_names_setup(char *str)
 225 {
 226         root_fs_names = str;
 227         return 1;
 228 }
 229
 230 __setup("rootflags=", root_data_setup);
 231 __setup("rootfstype=", fs_names_setup);
 232
 233 static void __init get_fs_names(char *page)
 234 {
 235         char *s = page;
 236
 237         if (root_fs_names) {
 238                 strcpy(page, root_fs_names);
 239                 while (*s++) {
 240                         if (s[-1] == ',')
 241                                 s[-1] = '\0';
 242                 }
 243         } else {
 244                 int len = get_filesystem_list(page);
 245                 char *p, *next;
 246
 247                 page[len] = '\0';
 248                 for (p = page-1; p; p = next) {
 249                         next = strchr(++p, '\n');
 250                         if (*p++ != '\t')
 251                                 continue;
 252                         while ((*s++ = *p++) != '\n')
 253                                 ;
 254                         s[-1] = '\0';
 255                 }
 256         }
 257         *s = '\0';
 258 }
 259
 260 static int __init do_mount_root(char *name, char *fs, int flags, void *data)
 261 {
 262         int err = sys_mount(name, "/root", fs, flags, data);
 263         if (err)
 264                 return err;
 265
 266         sys_chdir("/root");
 267         ROOT_DEV = current->fs->pwdmnt->mnt_sb->s_dev;
 268         printk("VFS: Mounted root (%s filesystem)%s.\n",
 269                current->fs->pwdmnt->mnt_sb->s_type->name,
 270                current->fs->pwdmnt->mnt_sb->s_flags & MS_RDONLY ?
 271                " readonly" : "");
 272         return 0;
 273 }
 274
 275 void __init mount_block_root(char *name, int flags)
 276 {
 277         char *fs_names = __getname();
 278         char *p;
 279         char b[BDEVNAME_SIZE];
 280
 281         get_fs_names(fs_names);
 282 retry:
 283         for (p = fs_names; *p; p += strlen(p)+1) {
 284                 int err = do_mount_root(name, p, flags, root_mount_data);
 285                 switch (err) {
 286                         case 0:
 287                                 goto out;
 288                         case -EACCES:
 289                                 flags |= MS_RDONLY;
 290                                 goto retry;
 291                         case -EINVAL:
 292                                 continue;
 293                 }
 294                 /*
 295                  * Allow the user to distinguish between failed sys_open
 296                  * and bad superblock on root device.
 297                  */
 298                 __bdevname(ROOT_DEV, b);
 299                 printk("VFS: Cannot open root device \"%s\" or %s\n",
 300                                 root_device_name, b);
 301                 printk("Please append a correct \"root=\" boot option\n");
 302
 303                 panic("VFS: Unable to mount root fs on %s", b);
 304         }
 305         panic("VFS: Unable to mount root fs on %s", __bdevname(ROOT_DEV, b));
 306 out:
 307         putname(fs_names);
 308 }
 309
 310 #ifdef CONFIG_ROOT_NFS
 311 static int __init mount_nfs_root(void)
 312 {
 313         void *data = nfs_root_data();
 314
 315         create_dev("/dev/root", ROOT_DEV, NULL);
 316         if (data &&
 317             do_mount_root("/dev/root", "nfs", root_mountflags, data) == 0)
 318                 return 1;
 319         return 0;
 320 }
 321 #endif
 322
 323 #if defined(CONFIG_BLK_DEV_RAM) || defined(CONFIG_BLK_DEV_FD)
 324 void __init change_floppy(char *fmt, ...)
 325 {
 326         struct termios termios;
 327         char buf[80];
 328         char c;
 329         int fd;
 330         va_list args;
 331         va_start(args, fmt);
 332         vsprintf(buf, fmt, args);
 333         va_end(args);
 334         fd = sys_open("/dev/root", O_RDWR | O_NDELAY, 0);
 335         if (fd >= 0) {
 336                 sys_ioctl(fd, FDEJECT, 0);
 337                 sys_close(fd);
 338         }
 339         printk(KERN_NOTICE "VFS: Insert %s and press ENTER\n", buf);
 340         fd = sys_open("/dev/console", O_RDWR, 0);
 341         if (fd >= 0) {
 342                 sys_ioctl(fd, TCGETS, (long)&termios);
 343                 termios.c_lflag &= ~ICANON;
 344                 sys_ioctl(fd, TCSETSF, (long)&termios);
 345                 sys_read(fd, &c, 1);
 346                 termios.c_lflag |= ICANON;
 347                 sys_ioctl(fd, TCSETSF, (long)&termios);
 348                 sys_close(fd);
 349         }
 350 }
 351 #endif
 352
 353 void __init mount_root(void)
 354 {
 355 #ifdef CONFIG_ROOT_NFS
 356         if (MAJOR(ROOT_DEV) == UNNAMED_MAJOR) {
 357                 if (mount_nfs_root())
 358                         return;
 359
 360                 printk(KERN_ERR "VFS: Unable to mount root fs via NFS, trying floppy.\n");
 361                 ROOT_DEV = Root_FD0;
 362         }
 363 #endif
 364 #ifdef CONFIG_BLK_DEV_FD
 365         if (MAJOR(ROOT_DEV) == FLOPPY_MAJOR) {
 366                 /* rd_doload is 2 for a dual initrd/ramload setup */
 367                 if (rd_doload==2) {
 368                         if (rd_load_disk(1)) {
 369                                 ROOT_DEV = Root_RAM1;
 370                                 root_device_name = NULL;
 371                         }
 372                 } else
 373                         change_floppy("root floppy");
 374         }
 375 #endif
 376         create_dev("/dev/root", ROOT_DEV, root_device_name);
 377         mount_block_root("/dev/root", root_mountflags);
 378 }
 379
 380 /*
 381  * Prepare the namespace - decide what/where to mount, load ramdisks, etc.
 382  */
 383 void __init prepare_namespace(void)
 384 {
 385         int is_floppy;
 386
 387         mount_devfs();
 388
 389         md_run_setup();
 390
 391         if (saved_root_name[0]) {
 392                 root_device_name = saved_root_name;
 393                 ROOT_DEV = name_to_dev_t(root_device_name);
 394                 if (strncmp(root_device_name, "/dev/", 5) == 0)
 395                         root_device_name += 5;
 396         }
 397
 398         is_floppy = MAJOR(ROOT_DEV) == FLOPPY_MAJOR;
 399
 400         if (initrd_load())
 401                 goto out;
 402
 403         if (is_floppy && rd_doload && rd_load_disk(0))
 404                 ROOT_DEV = Root_RAM0;
 405
 406         mount_root();
 407 out:
 408         umount_devfs("/dev");
 409         sys_mount(".", "/", NULL, MS_MOVE, NULL);
 410         sys_chroot(".");
 411         security_sb_post_mountroot();
 412         mount_devfs_fs ();
 413 }
 414