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 = open(path, 0, 0);
  70         if (fd < 0)
  71                 goto fail;
  72         len = read(fd, buf, 32);
  73         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 = open(path, 0, 0);
 100         if (fd < 0)
 101                 goto fail;
 102         len = read(fd, buf, 32);
 103         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  *      dots.  try_name() does the actual checks, assuming that driverfs
 134  *      is mounted on rootfs /sys.
 135  */
 136
 137 dev_t name_to_dev_t(char *name)
 138 {
 139         char s[32];
 140         char *p;
 141         dev_t res = 0;
 142         int part;
 143
 144         sys_mkdir("/sys", 0700);
 145         if (sys_mount("sysfs", "/sys", "sysfs", 0, NULL) < 0)
 146                 goto out;
 147
 148         if (strncmp(name, "/dev/", 5) != 0) {
 149                 unsigned maj, min;
 150
 151                 if (sscanf(name, "%u:%u", &maj, &min) == 2) {
 152                         res = MKDEV(maj, min);
 153                         if (maj != MAJOR(res) || min != MINOR(res))
 154                                 goto fail;
 155                 } else {
 156                         res = new_decode_dev(simple_strtoul(name, &p, 16));
 157                         if (*p)
 158                                 goto fail;
 159                 }
 160                 goto done;
 161         }
 162         name += 5;
 163         res = Root_NFS;
 164         if (strcmp(name, "nfs") == 0)
 165                 goto done;
 166
 167         if (strlen(name) > 31)
 168                 goto fail;
 169         strcpy(s, name);
 170         for (p = s; *p; p++)
 171                 if (*p == '/')
 172                         *p = '.';
 173         res = try_name(s, 0);
 174         if (res)
 175                 goto done;
 176
 177         while (p > s && isdigit(p[-1]))
 178                 p--;
 179         if (p == s || !*p || *p == '0')
 180                 goto fail;
 181         part = simple_strtoul(p, NULL, 10);
 182         *p = '\0';
 183         res = try_name(s, part);
 184         if (res)
 185                 goto done;
 186
 187         if (p < s + 2 || !isdigit(p[-2]) || p[-1] != 'p')
 188                 goto fail;
 189         p[-1] = '\0';
 190         res = try_name(s, part);
 191 done:
 192         sys_umount("/sys", 0);
 193 out:
 194         sys_rmdir("/sys");
 195         return res;
 196 fail:
 197         res = 0;
 198         goto done;
 199 }
 200
 201 static int __init root_dev_setup(char *line)
 202 {
 203         strlcpy(saved_root_name, line, sizeof(saved_root_name));
 204         return 1;
 205 }
 206
 207 __setup("root=", root_dev_setup);
 208
 209 static char * __initdata root_mount_data;
 210 static int __init root_data_setup(char *str)
 211 {
 212         root_mount_data = str;
 213         return 1;
 214 }
 215
 216 static char * __initdata root_fs_names;
 217 static int __init fs_names_setup(char *str)
 218 {
 219         root_fs_names = str;
 220         return 1;
 221 }
 222
 223 __setup("rootflags=", root_data_setup);
 224 __setup("rootfstype=", fs_names_setup);
 225
 226 static void __init get_fs_names(char *page)
 227 {
 228         char *s = page;
 229
 230         if (root_fs_names) {
 231                 strcpy(page, root_fs_names);
 232                 while (*s++) {
 233                         if (s[-1] == ',')
 234                                 s[-1] = '\0';
 235                 }
 236         } else {
 237                 int len = get_filesystem_list(page);
 238                 char *p, *next;
 239
 240                 page[len] = '\0';
 241                 for (p = page-1; p; p = next) {
 242                         next = strchr(++p, '\n');
 243                         if (*p++ != '\t')
 244                                 continue;
 245                         while ((*s++ = *p++) != '\n')
 246                                 ;
 247                         s[-1] = '\0';
 248                 }
 249         }
 250         *s = '\0';
 251 }
 252
 253 static int __init do_mount_root(char *name, char *fs, int flags, void *data)
 254 {
 255         int err = sys_mount(name, "/root", fs, flags, data);
 256         if (err)
 257                 return err;
 258
 259         sys_chdir("/root");
 260         ROOT_DEV = current->fs->pwdmnt->mnt_sb->s_dev;
 261         printk("VFS: Mounted root (%s filesystem)%s.\n",
 262                current->fs->pwdmnt->mnt_sb->s_type->name,
 263                current->fs->pwdmnt->mnt_sb->s_flags & MS_RDONLY ?
 264                " readonly" : "");
 265         return 0;
 266 }
 267
 268 void __init mount_block_root(char *name, int flags)
 269 {
 270         char *fs_names = __getname();
 271         char *p;
 272         char b[BDEVNAME_SIZE];
 273
 274         get_fs_names(fs_names);
 275 retry:
 276         for (p = fs_names; *p; p += strlen(p)+1) {
 277                 int err = do_mount_root(name, p, flags, root_mount_data);
 278                 switch (err) {
 279                         case 0:
 280                                 goto out;
 281                         case -EACCES:
 282                                 flags |= MS_RDONLY;
 283                                 goto retry;
 284                         case -EINVAL:
 285                                 continue;
 286                 }
 287                 /*
 288                  * Allow the user to distinguish between failed open
 289                  * and bad superblock on root device.
 290                  */
 291                 __bdevname(ROOT_DEV, b);
 292                 printk("VFS: Cannot open root device \"%s\" or %s\n",
 293                                 root_device_name, b);
 294                 printk("Please append a correct \"root=\" boot option\n");
 295
 296                 panic("VFS: Unable to mount root fs on %s", b);
 297         }
 298         panic("VFS: Unable to mount root fs on %s", __bdevname(ROOT_DEV, b));
 299 out:
 300         putname(fs_names);
 301 }
 302
 303 #ifdef CONFIG_ROOT_NFS
 304 static int __init mount_nfs_root(void)
 305 {
 306         void *data = nfs_root_data();
 307
 308         create_dev("/dev/root", ROOT_DEV, NULL);
 309         if (data &&
 310             do_mount_root("/dev/root", "nfs", root_mountflags, data) == 0)
 311                 return 1;
 312         return 0;
 313 }
 314 #endif
 315
 316 #if defined(CONFIG_BLK_DEV_RAM) || defined(CONFIG_BLK_DEV_FD)
 317 void __init change_floppy(char *fmt, ...)
 318 {
 319         struct termios termios;
 320         char buf[80];
 321         char c;
 322         int fd;
 323         va_list args;
 324         va_start(args, fmt);
 325         vsprintf(buf, fmt, args);
 326         va_end(args);
 327         fd = open("/dev/root", O_RDWR | O_NDELAY, 0);
 328         if (fd >= 0) {
 329                 sys_ioctl(fd, FDEJECT, 0);
 330                 close(fd);
 331         }
 332         printk(KERN_NOTICE "VFS: Insert %s and press ENTER\n", buf);
 333         fd = open("/dev/console", O_RDWR, 0);
 334         if (fd >= 0) {
 335                 sys_ioctl(fd, TCGETS, (long)&termios);
 336                 termios.c_lflag &= ~ICANON;
 337                 sys_ioctl(fd, TCSETSF, (long)&termios);
 338                 read(fd, &c, 1);
 339                 termios.c_lflag |= ICANON;
 340                 sys_ioctl(fd, TCSETSF, (long)&termios);
 341                 close(fd);
 342         }
 343 }
 344 #endif
 345
 346 void __init mount_root(void)
 347 {
 348 #ifdef CONFIG_ROOT_NFS
 349         if (MAJOR(ROOT_DEV) == UNNAMED_MAJOR) {
 350                 if (mount_nfs_root())
 351                         return;
 352
 353                 printk(KERN_ERR "VFS: Unable to mount root fs via NFS, trying floppy.\n");
 354                 ROOT_DEV = Root_FD0;
 355         }
 356 #endif
 357 #ifdef CONFIG_BLK_DEV_FD
 358         if (MAJOR(ROOT_DEV) == FLOPPY_MAJOR) {
 359                 /* rd_doload is 2 for a dual initrd/ramload setup */
 360                 if (rd_doload==2) {
 361                         if (rd_load_disk(1)) {
 362                                 ROOT_DEV = Root_RAM1;
 363                                 root_device_name = NULL;
 364                         }
 365                 } else
 366                         change_floppy("root floppy");
 367         }
 368 #endif
 369         create_dev("/dev/root", ROOT_DEV, root_device_name);
 370         mount_block_root("/dev/root", root_mountflags);
 371 }
 372
 373 /*
 374  * Prepare the namespace - decide what/where to mount, load ramdisks, etc.
 375  */
 376 void __init prepare_namespace(void)
 377 {
 378         int is_floppy;
 379
 380         mount_devfs();
 381
 382         md_run_setup();
 383
 384         if (saved_root_name[0]) {
 385                 root_device_name = saved_root_name;
 386                 ROOT_DEV = name_to_dev_t(root_device_name);
 387                 if (strncmp(root_device_name, "/dev/", 5) == 0)
 388                         root_device_name += 5;
 389         }
 390
 391         is_floppy = MAJOR(ROOT_DEV) == FLOPPY_MAJOR;
 392
 393         if (initrd_load())
 394                 goto out;
 395
 396         if (is_floppy && rd_doload && rd_load_disk(0))
 397                 ROOT_DEV = Root_RAM0;
 398
 399         mount_root();
 400 out:
 401         umount_devfs("/dev");
 402         sys_mount(".", "/", NULL, MS_MOVE, NULL);
 403         sys_chroot(".");
 404         security_sb_post_mountroot();
 405         mount_devfs_fs ();
 406 }
 407