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 #include <linux/ramfs.h> 30 #include <linux/shmem_fs.h> 31 32 #include <linux/nfs_fs.h> 33 #include <linux/nfs_fs_sb.h> 34 #include <linux/nfs_mount.h> 35 36 #include "do_mounts.h" 37 38 int __initdata rd_doload; /* 1 = load RAM disk, 0 = don't load */ 39 40 int root_mountflags = MS_RDONLY | MS_SILENT; 41 static char * __initdata root_device_name; 42 static char __initdata saved_root_name[64]; 43 static int root_wait; 44 45 dev_t ROOT_DEV; 46 47 static int __init load_ramdisk(char *str) 48 { 49 rd_doload = simple_strtol(str,NULL,0) & 3; 50 return 1; 51 } 52 __setup("load_ramdisk=", load_ramdisk); 53 54 static int __init readonly(char *str) 55 { 56 if (*str) 57 return 0; 58 root_mountflags |= MS_RDONLY; 59 return 1; 60 } 61 62 static int __init readwrite(char *str) 63 { 64 if (*str) 65 return 0; 66 root_mountflags &= ~MS_RDONLY; 67 return 1; 68 } 69 70 __setup("ro", readonly); 71 __setup("rw", readwrite); 72 73 #ifdef CONFIG_BLOCK 74 struct uuidcmp { 75 const char *uuid; 76 int len; 77 }; 78 79 /** 80 * match_dev_by_uuid - callback for finding a partition using its uuid 81 * @dev: device passed in by the caller 82 * @data: opaque pointer to the desired struct uuidcmp to match 83 * 84 * Returns 1 if the device matches, and 0 otherwise. 85 */ 86 static int match_dev_by_uuid(struct device *dev, const void *data) 87 { 88 const struct uuidcmp *cmp = data; 89 struct hd_struct *part = dev_to_part(dev); 90 91 if (!part->info) 92 goto no_match; 93 94 if (strncasecmp(cmp->uuid, part->info->uuid, cmp->len)) 95 goto no_match; 96 97 return 1; 98 no_match: 99 return 0; 100 } 101 102 103 /** 104 * devt_from_partuuid - looks up the dev_t of a partition by its UUID 105 * @uuid_str: char array containing ascii UUID 106 * 107 * The function will return the first partition which contains a matching 108 * UUID value in its partition_meta_info struct. This does not search 109 * by filesystem UUIDs. 110 * 111 * If @uuid_str is followed by a "/PARTNROFF=%d", then the number will be 112 * extracted and used as an offset from the partition identified by the UUID. 113 * 114 * Returns the matching dev_t on success or 0 on failure. 115 */ 116 static dev_t devt_from_partuuid(const char *uuid_str) 117 { 118 dev_t res = 0; 119 struct uuidcmp cmp; 120 struct device *dev = NULL; 121 struct gendisk *disk; 122 struct hd_struct *part; 123 int offset = 0; 124 bool clear_root_wait = false; 125 char *slash; 126 127 cmp.uuid = uuid_str; 128 129 slash = strchr(uuid_str, '/'); 130 /* Check for optional partition number offset attributes. */ 131 if (slash) { 132 char c = 0; 133 /* Explicitly fail on poor PARTUUID syntax. */ 134 if (sscanf(slash + 1, 135 "PARTNROFF=%d%c", &offset, &c) != 1) { 136 clear_root_wait = true; 137 goto done; 138 } 139 cmp.len = slash - uuid_str; 140 } else { 141 cmp.len = strlen(uuid_str); 142 } 143 144 if (!cmp.len) { 145 clear_root_wait = true; 146 goto done; 147 } 148 149 dev = class_find_device(&block_class, NULL, &cmp, 150 &match_dev_by_uuid); 151 if (!dev) 152 goto done; 153 154 res = dev->devt; 155 156 /* Attempt to find the partition by offset. */ 157 if (!offset) 158 goto no_offset; 159 160 res = 0; 161 disk = part_to_disk(dev_to_part(dev)); 162 part = disk_get_part(disk, dev_to_part(dev)->partno + offset); 163 if (part) { 164 res = part_devt(part); 165 put_device(part_to_dev(part)); 166 } 167 168 no_offset: 169 put_device(dev); 170 done: 171 if (clear_root_wait) { 172 pr_err("VFS: PARTUUID= is invalid.\n" 173 "Expected PARTUUID=<valid-uuid-id>[/PARTNROFF=%%d]\n"); 174 if (root_wait) 175 pr_err("Disabling rootwait; root= is invalid.\n"); 176 root_wait = 0; 177 } 178 return res; 179 } 180 #endif 181 182 /* 183 * Convert a name into device number. We accept the following variants: 184 * 185 * 1) <hex_major><hex_minor> device number in hexadecimal represents itself 186 * no leading 0x, for example b302. 187 * 2) /dev/nfs represents Root_NFS (0xff) 188 * 3) /dev/<disk_name> represents the device number of disk 189 * 4) /dev/<disk_name><decimal> represents the device number 190 * of partition - device number of disk plus the partition number 191 * 5) /dev/<disk_name>p<decimal> - same as the above, that form is 192 * used when disk name of partitioned disk ends on a digit. 193 * 6) PARTUUID=00112233-4455-6677-8899-AABBCCDDEEFF representing the 194 * unique id of a partition if the partition table provides it. 195 * The UUID may be either an EFI/GPT UUID, or refer to an MSDOS 196 * partition using the format SSSSSSSS-PP, where SSSSSSSS is a zero- 197 * filled hex representation of the 32-bit "NT disk signature", and PP 198 * is a zero-filled hex representation of the 1-based partition number. 199 * 7) PARTUUID=<UUID>/PARTNROFF=<int> to select a partition in relation to 200 * a partition with a known unique id. 201 * 8) <major>:<minor> major and minor number of the device separated by 202 * a colon. 203 * 204 * If name doesn't have fall into the categories above, we return (0,0). 205 * block_class is used to check if something is a disk name. If the disk 206 * name contains slashes, the device name has them replaced with 207 * bangs. 208 */ 209 210 dev_t name_to_dev_t(char *name) 211 { 212 char s[32]; 213 char *p; 214 dev_t res = 0; 215 int part; 216 217 #ifdef CONFIG_BLOCK 218 if (strncmp(name, "PARTUUID=", 9) == 0) { 219 name += 9; 220 res = devt_from_partuuid(name); 221 if (!res) 222 goto fail; 223 goto done; 224 } 225 #endif 226 227 if (strncmp(name, "/dev/", 5) != 0) { 228 unsigned maj, min; 229 230 if (sscanf(name, "%u:%u", &maj, &min) == 2) { 231 res = MKDEV(maj, min); 232 if (maj != MAJOR(res) || min != MINOR(res)) 233 goto fail; 234 } else { 235 res = new_decode_dev(simple_strtoul(name, &p, 16)); 236 if (*p) 237 goto fail; 238 } 239 goto done; 240 } 241 242 name += 5; 243 res = Root_NFS; 244 if (strcmp(name, "nfs") == 0) 245 goto done; 246 res = Root_RAM0; 247 if (strcmp(name, "ram") == 0) 248 goto done; 249 250 if (strlen(name) > 31) 251 goto fail; 252 strcpy(s, name); 253 for (p = s; *p; p++) 254 if (*p == '/') 255 *p = '!'; 256 res = blk_lookup_devt(s, 0); 257 if (res) 258 goto done; 259 260 /* 261 * try non-existent, but valid partition, which may only exist 262 * after revalidating the disk, like partitioned md devices 263 */ 264 while (p > s && isdigit(p[-1])) 265 p--; 266 if (p == s || !*p || *p == '0') 267 goto fail; 268 269 /* try disk name without <part number> */ 270 part = simple_strtoul(p, NULL, 10); 271 *p = '\0'; 272 res = blk_lookup_devt(s, part); 273 if (res) 274 goto done; 275 276 /* try disk name without p<part number> */ 277 if (p < s + 2 || !isdigit(p[-2]) || p[-1] != 'p') 278 goto fail; 279 p[-1] = '\0'; 280 res = blk_lookup_devt(s, part); 281 if (res) 282 goto done; 283 284 fail: 285 return 0; 286 done: 287 return res; 288 } 289 290 static int __init root_dev_setup(char *line) 291 { 292 strlcpy(saved_root_name, line, sizeof(saved_root_name)); 293 return 1; 294 } 295 296 __setup("root=", root_dev_setup); 297 298 static int __init rootwait_setup(char *str) 299 { 300 if (*str) 301 return 0; 302 root_wait = 1; 303 return 1; 304 } 305 306 __setup("rootwait", rootwait_setup); 307 308 static char * __initdata root_mount_data; 309 static int __init root_data_setup(char *str) 310 { 311 root_mount_data = str; 312 return 1; 313 } 314 315 static char * __initdata root_fs_names; 316 static int __init fs_names_setup(char *str) 317 { 318 root_fs_names = str; 319 return 1; 320 } 321 322 static unsigned int __initdata root_delay; 323 static int __init root_delay_setup(char *str) 324 { 325 root_delay = simple_strtoul(str, NULL, 0); 326 return 1; 327 } 328 329 __setup("rootflags=", root_data_setup); 330 __setup("rootfstype=", fs_names_setup); 331 __setup("rootdelay=", root_delay_setup); 332 333 static void __init get_fs_names(char *page) 334 { 335 char *s = page; 336 337 if (root_fs_names) { 338 strcpy(page, root_fs_names); 339 while (*s++) { 340 if (s[-1] == ',') 341 s[-1] = '\0'; 342 } 343 } else { 344 int len = get_filesystem_list(page); 345 char *p, *next; 346 347 page[len] = '\0'; 348 for (p = page-1; p; p = next) { 349 next = strchr(++p, '\n'); 350 if (*p++ != '\t') 351 continue; 352 while ((*s++ = *p++) != '\n') 353 ; 354 s[-1] = '\0'; 355 } 356 } 357 *s = '\0'; 358 } 359 360 static int __init do_mount_root(char *name, char *fs, int flags, void *data) 361 { 362 struct super_block *s; 363 int err = sys_mount(name, "/root", fs, flags, data); 364 if (err) 365 return err; 366 367 sys_chdir("/root"); 368 s = current->fs->pwd.dentry->d_sb; 369 ROOT_DEV = s->s_dev; 370 printk(KERN_INFO 371 "VFS: Mounted root (%s filesystem)%s on device %u:%u.\n", 372 s->s_type->name, 373 s->s_flags & MS_RDONLY ? " readonly" : "", 374 MAJOR(ROOT_DEV), MINOR(ROOT_DEV)); 375 return 0; 376 } 377 378 void __init mount_block_root(char *name, int flags) 379 { 380 struct page *page = alloc_page(GFP_KERNEL | 381 __GFP_NOTRACK_FALSE_POSITIVE); 382 char *fs_names = page_address(page); 383 char *p; 384 #ifdef CONFIG_BLOCK 385 char b[BDEVNAME_SIZE]; 386 #else 387 const char *b = name; 388 #endif 389 390 get_fs_names(fs_names); 391 retry: 392 for (p = fs_names; *p; p += strlen(p)+1) { 393 int err = do_mount_root(name, p, flags, root_mount_data); 394 switch (err) { 395 case 0: 396 goto out; 397 case -EACCES: 398 flags |= MS_RDONLY; 399 goto retry; 400 case -EINVAL: 401 continue; 402 } 403 /* 404 * Allow the user to distinguish between failed sys_open 405 * and bad superblock on root device. 406 * and give them a list of the available devices 407 */ 408 #ifdef CONFIG_BLOCK 409 __bdevname(ROOT_DEV, b); 410 #endif 411 printk("VFS: Cannot open root device \"%s\" or %s: error %d\n", 412 root_device_name, b, err); 413 printk("Please append a correct \"root=\" boot option; here are the available partitions:\n"); 414 415 printk_all_partitions(); 416 #ifdef CONFIG_DEBUG_BLOCK_EXT_DEVT 417 printk("DEBUG_BLOCK_EXT_DEVT is enabled, you need to specify " 418 "explicit textual name for \"root=\" boot option.\n"); 419 #endif 420 panic("VFS: Unable to mount root fs on %s", b); 421 } 422 423 printk("List of all partitions:\n"); 424 printk_all_partitions(); 425 printk("No filesystem could mount root, tried: "); 426 for (p = fs_names; *p; p += strlen(p)+1) 427 printk(" %s", p); 428 printk("\n"); 429 #ifdef CONFIG_BLOCK 430 __bdevname(ROOT_DEV, b); 431 #endif 432 panic("VFS: Unable to mount root fs on %s", b); 433 out: 434 put_page(page); 435 } 436 437 #ifdef CONFIG_ROOT_NFS 438 439 #define NFSROOT_TIMEOUT_MIN 5 440 #define NFSROOT_TIMEOUT_MAX 30 441 #define NFSROOT_RETRY_MAX 5 442 443 static int __init mount_nfs_root(void) 444 { 445 char *root_dev, *root_data; 446 unsigned int timeout; 447 int try, err; 448 449 err = nfs_root_data(&root_dev, &root_data); 450 if (err != 0) 451 return 0; 452 453 /* 454 * The server or network may not be ready, so try several 455 * times. Stop after a few tries in case the client wants 456 * to fall back to other boot methods. 457 */ 458 timeout = NFSROOT_TIMEOUT_MIN; 459 for (try = 1; ; try++) { 460 err = do_mount_root(root_dev, "nfs", 461 root_mountflags, root_data); 462 if (err == 0) 463 return 1; 464 if (try > NFSROOT_RETRY_MAX) 465 break; 466 467 /* Wait, in case the server refused us immediately */ 468 ssleep(timeout); 469 timeout <<= 1; 470 if (timeout > NFSROOT_TIMEOUT_MAX) 471 timeout = NFSROOT_TIMEOUT_MAX; 472 } 473 return 0; 474 } 475 #endif 476 477 #if defined(CONFIG_BLK_DEV_RAM) || defined(CONFIG_BLK_DEV_FD) 478 void __init change_floppy(char *fmt, ...) 479 { 480 struct termios termios; 481 char buf[80]; 482 char c; 483 int fd; 484 va_list args; 485 va_start(args, fmt); 486 vsprintf(buf, fmt, args); 487 va_end(args); 488 fd = sys_open("/dev/root", O_RDWR | O_NDELAY, 0); 489 if (fd >= 0) { 490 sys_ioctl(fd, FDEJECT, 0); 491 sys_close(fd); 492 } 493 printk(KERN_NOTICE "VFS: Insert %s and press ENTER\n", buf); 494 fd = sys_open("/dev/console", O_RDWR, 0); 495 if (fd >= 0) { 496 sys_ioctl(fd, TCGETS, (long)&termios); 497 termios.c_lflag &= ~ICANON; 498 sys_ioctl(fd, TCSETSF, (long)&termios); 499 sys_read(fd, &c, 1); 500 termios.c_lflag |= ICANON; 501 sys_ioctl(fd, TCSETSF, (long)&termios); 502 sys_close(fd); 503 } 504 } 505 #endif 506 507 void __init mount_root(void) 508 { 509 #ifdef CONFIG_ROOT_NFS 510 if (ROOT_DEV == Root_NFS) { 511 if (mount_nfs_root()) 512 return; 513 514 printk(KERN_ERR "VFS: Unable to mount root fs via NFS, trying floppy.\n"); 515 ROOT_DEV = Root_FD0; 516 } 517 #endif 518 #ifdef CONFIG_BLK_DEV_FD 519 if (MAJOR(ROOT_DEV) == FLOPPY_MAJOR) { 520 /* rd_doload is 2 for a dual initrd/ramload setup */ 521 if (rd_doload==2) { 522 if (rd_load_disk(1)) { 523 ROOT_DEV = Root_RAM1; 524 root_device_name = NULL; 525 } 526 } else 527 change_floppy("root floppy"); 528 } 529 #endif 530 #ifdef CONFIG_BLOCK 531 create_dev("/dev/root", ROOT_DEV); 532 mount_block_root("/dev/root", root_mountflags); 533 #endif 534 } 535 536 /* 537 * Prepare the namespace - decide what/where to mount, load ramdisks, etc. 538 */ 539 void __init prepare_namespace(void) 540 { 541 int is_floppy; 542 543 if (root_delay) { 544 printk(KERN_INFO "Waiting %d sec before mounting root device...\n", 545 root_delay); 546 ssleep(root_delay); 547 } 548 549 /* 550 * wait for the known devices to complete their probing 551 * 552 * Note: this is a potential source of long boot delays. 553 * For example, it is not atypical to wait 5 seconds here 554 * for the touchpad of a laptop to initialize. 555 */ 556 wait_for_device_probe(); 557 558 md_run_setup(); 559 560 if (saved_root_name[0]) { 561 root_device_name = saved_root_name; 562 if (!strncmp(root_device_name, "mtd", 3) || 563 !strncmp(root_device_name, "ubi", 3)) { 564 mount_block_root(root_device_name, root_mountflags); 565 goto out; 566 } 567 ROOT_DEV = name_to_dev_t(root_device_name); 568 if (strncmp(root_device_name, "/dev/", 5) == 0) 569 root_device_name += 5; 570 } 571 572 if (initrd_load()) 573 goto out; 574 575 /* wait for any asynchronous scanning to complete */ 576 if ((ROOT_DEV == 0) && root_wait) { 577 printk(KERN_INFO "Waiting for root device %s...\n", 578 saved_root_name); 579 while (driver_probe_done() != 0 || 580 (ROOT_DEV = name_to_dev_t(saved_root_name)) == 0) 581 msleep(100); 582 async_synchronize_full(); 583 } 584 585 is_floppy = MAJOR(ROOT_DEV) == FLOPPY_MAJOR; 586 587 if (is_floppy && rd_doload && rd_load_disk(0)) 588 ROOT_DEV = Root_RAM0; 589 590 mount_root(); 591 out: 592 devtmpfs_mount("dev"); 593 sys_mount(".", "/", NULL, MS_MOVE, NULL); 594 sys_chroot("."); 595 } 596 597 static bool is_tmpfs; 598 static struct dentry *rootfs_mount(struct file_system_type *fs_type, 599 int flags, const char *dev_name, void *data) 600 { 601 static unsigned long once; 602 void *fill = ramfs_fill_super; 603 604 if (test_and_set_bit(0, &once)) 605 return ERR_PTR(-ENODEV); 606 607 if (IS_ENABLED(CONFIG_TMPFS) && is_tmpfs) 608 fill = shmem_fill_super; 609 610 return mount_nodev(fs_type, flags, data, fill); 611 } 612 613 static struct file_system_type rootfs_fs_type = { 614 .name = "rootfs", 615 .mount = rootfs_mount, 616 .kill_sb = kill_litter_super, 617 }; 618 619 int __init init_rootfs(void) 620 { 621 int err = register_filesystem(&rootfs_fs_type); 622 623 if (err) 624 return err; 625 626 if (IS_ENABLED(CONFIG_TMPFS) && !saved_root_name[0] && 627 (!root_fs_names || strstr(root_fs_names, "tmpfs"))) { 628 err = shmem_init(); 629 is_tmpfs = true; 630 } else { 631 err = init_ramfs_fs(); 632 } 633 634 if (err) 635 unregister_filesystem(&rootfs_fs_type); 636 637 return err; 638 } 639