1 // SPDX-License-Identifier: GPL-2.0-only 2 #include <linux/module.h> 3 #include <linux/sched.h> 4 #include <linux/ctype.h> 5 #include <linux/fd.h> 6 #include <linux/tty.h> 7 #include <linux/suspend.h> 8 #include <linux/root_dev.h> 9 #include <linux/security.h> 10 #include <linux/delay.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 #include <linux/ramfs.h> 20 #include <linux/shmem_fs.h> 21 22 #include <linux/nfs_fs.h> 23 #include <linux/nfs_fs_sb.h> 24 #include <linux/nfs_mount.h> 25 #include <linux/raid/detect.h> 26 #include <uapi/linux/mount.h> 27 28 #include "do_mounts.h" 29 30 int root_mountflags = MS_RDONLY | MS_SILENT; 31 static char * __initdata root_device_name; 32 static char __initdata saved_root_name[64]; 33 static int root_wait; 34 35 dev_t ROOT_DEV; 36 37 static int __init load_ramdisk(char *str) 38 { 39 pr_warn("ignoring the deprecated load_ramdisk= option\n"); 40 return 1; 41 } 42 __setup("load_ramdisk=", load_ramdisk); 43 44 static int __init readonly(char *str) 45 { 46 if (*str) 47 return 0; 48 root_mountflags |= MS_RDONLY; 49 return 1; 50 } 51 52 static int __init readwrite(char *str) 53 { 54 if (*str) 55 return 0; 56 root_mountflags &= ~MS_RDONLY; 57 return 1; 58 } 59 60 __setup("ro", readonly); 61 __setup("rw", readwrite); 62 63 #ifdef CONFIG_BLOCK 64 struct uuidcmp { 65 const char *uuid; 66 int len; 67 }; 68 69 /** 70 * match_dev_by_uuid - callback for finding a partition using its uuid 71 * @dev: device passed in by the caller 72 * @data: opaque pointer to the desired struct uuidcmp to match 73 * 74 * Returns 1 if the device matches, and 0 otherwise. 75 */ 76 static int match_dev_by_uuid(struct device *dev, const void *data) 77 { 78 struct block_device *bdev = dev_to_bdev(dev); 79 const struct uuidcmp *cmp = data; 80 81 if (!bdev->bd_meta_info || 82 strncasecmp(cmp->uuid, bdev->bd_meta_info->uuid, cmp->len)) 83 return 0; 84 return 1; 85 } 86 87 /** 88 * devt_from_partuuid - looks up the dev_t of a partition by its UUID 89 * @uuid_str: char array containing ascii UUID 90 * 91 * The function will return the first partition which contains a matching 92 * UUID value in its partition_meta_info struct. This does not search 93 * by filesystem UUIDs. 94 * 95 * If @uuid_str is followed by a "/PARTNROFF=%d", then the number will be 96 * extracted and used as an offset from the partition identified by the UUID. 97 * 98 * Returns the matching dev_t on success or 0 on failure. 99 */ 100 static dev_t devt_from_partuuid(const char *uuid_str) 101 { 102 struct uuidcmp cmp; 103 struct device *dev = NULL; 104 dev_t devt = 0; 105 int offset = 0; 106 char *slash; 107 108 cmp.uuid = uuid_str; 109 110 slash = strchr(uuid_str, '/'); 111 /* Check for optional partition number offset attributes. */ 112 if (slash) { 113 char c = 0; 114 115 /* Explicitly fail on poor PARTUUID syntax. */ 116 if (sscanf(slash + 1, "PARTNROFF=%d%c", &offset, &c) != 1) 117 goto clear_root_wait; 118 cmp.len = slash - uuid_str; 119 } else { 120 cmp.len = strlen(uuid_str); 121 } 122 123 if (!cmp.len) 124 goto clear_root_wait; 125 126 dev = class_find_device(&block_class, NULL, &cmp, &match_dev_by_uuid); 127 if (!dev) 128 return 0; 129 130 if (offset) { 131 /* 132 * Attempt to find the requested partition by adding an offset 133 * to the partition number found by UUID. 134 */ 135 devt = part_devt(dev_to_disk(dev), 136 dev_to_bdev(dev)->bd_partno + offset); 137 } else { 138 devt = dev->devt; 139 } 140 141 put_device(dev); 142 return devt; 143 144 clear_root_wait: 145 pr_err("VFS: PARTUUID= is invalid.\n" 146 "Expected PARTUUID=<valid-uuid-id>[/PARTNROFF=%%d]\n"); 147 if (root_wait) 148 pr_err("Disabling rootwait; root= is invalid.\n"); 149 root_wait = 0; 150 return 0; 151 } 152 153 /** 154 * match_dev_by_label - callback for finding a partition using its label 155 * @dev: device passed in by the caller 156 * @data: opaque pointer to the label to match 157 * 158 * Returns 1 if the device matches, and 0 otherwise. 159 */ 160 static int match_dev_by_label(struct device *dev, const void *data) 161 { 162 struct block_device *bdev = dev_to_bdev(dev); 163 const char *label = data; 164 165 if (!bdev->bd_meta_info || strcmp(label, bdev->bd_meta_info->volname)) 166 return 0; 167 return 1; 168 } 169 170 static dev_t devt_from_partlabel(const char *label) 171 { 172 struct device *dev; 173 dev_t devt = 0; 174 175 dev = class_find_device(&block_class, NULL, label, &match_dev_by_label); 176 if (dev) { 177 devt = dev->devt; 178 put_device(dev); 179 } 180 181 return devt; 182 } 183 184 static dev_t devt_from_devname(const char *name) 185 { 186 dev_t devt = 0; 187 int part; 188 char s[32]; 189 char *p; 190 191 if (strlen(name) > 31) 192 return 0; 193 strcpy(s, name); 194 for (p = s; *p; p++) { 195 if (*p == '/') 196 *p = '!'; 197 } 198 199 devt = blk_lookup_devt(s, 0); 200 if (devt) 201 return devt; 202 203 /* 204 * Try non-existent, but valid partition, which may only exist after 205 * opening the device, like partitioned md devices. 206 */ 207 while (p > s && isdigit(p[-1])) 208 p--; 209 if (p == s || !*p || *p == '0') 210 return 0; 211 212 /* try disk name without <part number> */ 213 part = simple_strtoul(p, NULL, 10); 214 *p = '\0'; 215 devt = blk_lookup_devt(s, part); 216 if (devt) 217 return devt; 218 219 /* try disk name without p<part number> */ 220 if (p < s + 2 || !isdigit(p[-2]) || p[-1] != 'p') 221 return 0; 222 p[-1] = '\0'; 223 return blk_lookup_devt(s, part); 224 } 225 #endif /* CONFIG_BLOCK */ 226 227 static dev_t devt_from_devnum(const char *name) 228 { 229 unsigned maj, min, offset; 230 dev_t devt = 0; 231 char *p, dummy; 232 233 if (sscanf(name, "%u:%u%c", &maj, &min, &dummy) == 2 || 234 sscanf(name, "%u:%u:%u:%c", &maj, &min, &offset, &dummy) == 3) { 235 devt = MKDEV(maj, min); 236 if (maj != MAJOR(devt) || min != MINOR(devt)) 237 return 0; 238 } else { 239 devt = new_decode_dev(simple_strtoul(name, &p, 16)); 240 if (*p) 241 return 0; 242 } 243 244 return devt; 245 } 246 247 /* 248 * Convert a name into device number. We accept the following variants: 249 * 250 * 1) <hex_major><hex_minor> device number in hexadecimal represents itself 251 * no leading 0x, for example b302. 252 * 2) /dev/nfs represents Root_NFS (0xff) 253 * 3) /dev/<disk_name> represents the device number of disk 254 * 4) /dev/<disk_name><decimal> represents the device number 255 * of partition - device number of disk plus the partition number 256 * 5) /dev/<disk_name>p<decimal> - same as the above, that form is 257 * used when disk name of partitioned disk ends on a digit. 258 * 6) PARTUUID=00112233-4455-6677-8899-AABBCCDDEEFF representing the 259 * unique id of a partition if the partition table provides it. 260 * The UUID may be either an EFI/GPT UUID, or refer to an MSDOS 261 * partition using the format SSSSSSSS-PP, where SSSSSSSS is a zero- 262 * filled hex representation of the 32-bit "NT disk signature", and PP 263 * is a zero-filled hex representation of the 1-based partition number. 264 * 7) PARTUUID=<UUID>/PARTNROFF=<int> to select a partition in relation to 265 * a partition with a known unique id. 266 * 8) <major>:<minor> major and minor number of the device separated by 267 * a colon. 268 * 9) PARTLABEL=<name> with name being the GPT partition label. 269 * MSDOS partitions do not support labels! 270 * 10) /dev/cifs represents Root_CIFS (0xfe) 271 * 272 * If name doesn't have fall into the categories above, we return (0,0). 273 * block_class is used to check if something is a disk name. If the disk 274 * name contains slashes, the device name has them replaced with 275 * bangs. 276 */ 277 dev_t name_to_dev_t(const char *name) 278 { 279 if (strcmp(name, "/dev/nfs") == 0) 280 return Root_NFS; 281 if (strcmp(name, "/dev/cifs") == 0) 282 return Root_CIFS; 283 if (strcmp(name, "/dev/ram") == 0) 284 return Root_RAM0; 285 #ifdef CONFIG_BLOCK 286 if (strncmp(name, "PARTUUID=", 9) == 0) 287 return devt_from_partuuid(name + 9); 288 if (strncmp(name, "PARTLABEL=", 10) == 0) 289 return devt_from_partlabel(name + 10); 290 if (strncmp(name, "/dev/", 5) == 0) 291 return devt_from_devname(name + 5); 292 #endif 293 return devt_from_devnum(name); 294 } 295 EXPORT_SYMBOL_GPL(name_to_dev_t); 296 297 static int __init root_dev_setup(char *line) 298 { 299 strscpy(saved_root_name, line, sizeof(saved_root_name)); 300 return 1; 301 } 302 303 __setup("root=", root_dev_setup); 304 305 static int __init rootwait_setup(char *str) 306 { 307 if (*str) 308 return 0; 309 root_wait = 1; 310 return 1; 311 } 312 313 __setup("rootwait", rootwait_setup); 314 315 static char * __initdata root_mount_data; 316 static int __init root_data_setup(char *str) 317 { 318 root_mount_data = str; 319 return 1; 320 } 321 322 static char * __initdata root_fs_names; 323 static int __init fs_names_setup(char *str) 324 { 325 root_fs_names = str; 326 return 1; 327 } 328 329 static unsigned int __initdata root_delay; 330 static int __init root_delay_setup(char *str) 331 { 332 root_delay = simple_strtoul(str, NULL, 0); 333 return 1; 334 } 335 336 __setup("rootflags=", root_data_setup); 337 __setup("rootfstype=", fs_names_setup); 338 __setup("rootdelay=", root_delay_setup); 339 340 /* This can return zero length strings. Caller should check */ 341 static int __init split_fs_names(char *page, size_t size, char *names) 342 { 343 int count = 1; 344 char *p = page; 345 346 strscpy(p, root_fs_names, size); 347 while (*p++) { 348 if (p[-1] == ',') { 349 p[-1] = '\0'; 350 count++; 351 } 352 } 353 354 return count; 355 } 356 357 static int __init do_mount_root(const char *name, const char *fs, 358 const int flags, const void *data) 359 { 360 struct super_block *s; 361 struct page *p = NULL; 362 char *data_page = NULL; 363 int ret; 364 365 if (data) { 366 /* init_mount() requires a full page as fifth argument */ 367 p = alloc_page(GFP_KERNEL); 368 if (!p) 369 return -ENOMEM; 370 data_page = page_address(p); 371 /* zero-pad. init_mount() will make sure it's terminated */ 372 strncpy(data_page, data, PAGE_SIZE); 373 } 374 375 ret = init_mount(name, "/root", fs, flags, data_page); 376 if (ret) 377 goto out; 378 379 init_chdir("/root"); 380 s = current->fs->pwd.dentry->d_sb; 381 ROOT_DEV = s->s_dev; 382 printk(KERN_INFO 383 "VFS: Mounted root (%s filesystem)%s on device %u:%u.\n", 384 s->s_type->name, 385 sb_rdonly(s) ? " readonly" : "", 386 MAJOR(ROOT_DEV), MINOR(ROOT_DEV)); 387 388 out: 389 if (p) 390 put_page(p); 391 return ret; 392 } 393 394 void __init mount_block_root(char *name, int flags) 395 { 396 struct page *page = alloc_page(GFP_KERNEL); 397 char *fs_names = page_address(page); 398 char *p; 399 char b[BDEVNAME_SIZE]; 400 int num_fs, i; 401 402 scnprintf(b, BDEVNAME_SIZE, "unknown-block(%u,%u)", 403 MAJOR(ROOT_DEV), MINOR(ROOT_DEV)); 404 if (root_fs_names) 405 num_fs = split_fs_names(fs_names, PAGE_SIZE, root_fs_names); 406 else 407 num_fs = list_bdev_fs_names(fs_names, PAGE_SIZE); 408 retry: 409 for (i = 0, p = fs_names; i < num_fs; i++, p += strlen(p)+1) { 410 int err; 411 412 if (!*p) 413 continue; 414 err = do_mount_root(name, p, flags, root_mount_data); 415 switch (err) { 416 case 0: 417 goto out; 418 case -EACCES: 419 case -EINVAL: 420 continue; 421 } 422 /* 423 * Allow the user to distinguish between failed sys_open 424 * and bad superblock on root device. 425 * and give them a list of the available devices 426 */ 427 printk("VFS: Cannot open root device \"%s\" or %s: error %d\n", 428 root_device_name, b, err); 429 printk("Please append a correct \"root=\" boot option; here are the available partitions:\n"); 430 431 printk_all_partitions(); 432 panic("VFS: Unable to mount root fs on %s", b); 433 } 434 if (!(flags & SB_RDONLY)) { 435 flags |= SB_RDONLY; 436 goto retry; 437 } 438 439 printk("List of all partitions:\n"); 440 printk_all_partitions(); 441 printk("No filesystem could mount root, tried: "); 442 for (i = 0, p = fs_names; i < num_fs; i++, p += strlen(p)+1) 443 printk(" %s", p); 444 printk("\n"); 445 panic("VFS: Unable to mount root fs on %s", b); 446 out: 447 put_page(page); 448 } 449 450 #ifdef CONFIG_ROOT_NFS 451 452 #define NFSROOT_TIMEOUT_MIN 5 453 #define NFSROOT_TIMEOUT_MAX 30 454 #define NFSROOT_RETRY_MAX 5 455 456 static int __init mount_nfs_root(void) 457 { 458 char *root_dev, *root_data; 459 unsigned int timeout; 460 int try, err; 461 462 err = nfs_root_data(&root_dev, &root_data); 463 if (err != 0) 464 return 0; 465 466 /* 467 * The server or network may not be ready, so try several 468 * times. Stop after a few tries in case the client wants 469 * to fall back to other boot methods. 470 */ 471 timeout = NFSROOT_TIMEOUT_MIN; 472 for (try = 1; ; try++) { 473 err = do_mount_root(root_dev, "nfs", 474 root_mountflags, root_data); 475 if (err == 0) 476 return 1; 477 if (try > NFSROOT_RETRY_MAX) 478 break; 479 480 /* Wait, in case the server refused us immediately */ 481 ssleep(timeout); 482 timeout <<= 1; 483 if (timeout > NFSROOT_TIMEOUT_MAX) 484 timeout = NFSROOT_TIMEOUT_MAX; 485 } 486 return 0; 487 } 488 #endif 489 490 #ifdef CONFIG_CIFS_ROOT 491 492 extern int cifs_root_data(char **dev, char **opts); 493 494 #define CIFSROOT_TIMEOUT_MIN 5 495 #define CIFSROOT_TIMEOUT_MAX 30 496 #define CIFSROOT_RETRY_MAX 5 497 498 static int __init mount_cifs_root(void) 499 { 500 char *root_dev, *root_data; 501 unsigned int timeout; 502 int try, err; 503 504 err = cifs_root_data(&root_dev, &root_data); 505 if (err != 0) 506 return 0; 507 508 timeout = CIFSROOT_TIMEOUT_MIN; 509 for (try = 1; ; try++) { 510 err = do_mount_root(root_dev, "cifs", root_mountflags, 511 root_data); 512 if (err == 0) 513 return 1; 514 if (try > CIFSROOT_RETRY_MAX) 515 break; 516 517 ssleep(timeout); 518 timeout <<= 1; 519 if (timeout > CIFSROOT_TIMEOUT_MAX) 520 timeout = CIFSROOT_TIMEOUT_MAX; 521 } 522 return 0; 523 } 524 #endif 525 526 static bool __init fs_is_nodev(char *fstype) 527 { 528 struct file_system_type *fs = get_fs_type(fstype); 529 bool ret = false; 530 531 if (fs) { 532 ret = !(fs->fs_flags & FS_REQUIRES_DEV); 533 put_filesystem(fs); 534 } 535 536 return ret; 537 } 538 539 static int __init mount_nodev_root(void) 540 { 541 char *fs_names, *fstype; 542 int err = -EINVAL; 543 int num_fs, i; 544 545 fs_names = (void *)__get_free_page(GFP_KERNEL); 546 if (!fs_names) 547 return -EINVAL; 548 num_fs = split_fs_names(fs_names, PAGE_SIZE, root_fs_names); 549 550 for (i = 0, fstype = fs_names; i < num_fs; 551 i++, fstype += strlen(fstype) + 1) { 552 if (!*fstype) 553 continue; 554 if (!fs_is_nodev(fstype)) 555 continue; 556 err = do_mount_root(root_device_name, fstype, root_mountflags, 557 root_mount_data); 558 if (!err) 559 break; 560 } 561 562 free_page((unsigned long)fs_names); 563 return err; 564 } 565 566 void __init mount_root(void) 567 { 568 #ifdef CONFIG_ROOT_NFS 569 if (ROOT_DEV == Root_NFS) { 570 if (!mount_nfs_root()) 571 printk(KERN_ERR "VFS: Unable to mount root fs via NFS.\n"); 572 return; 573 } 574 #endif 575 #ifdef CONFIG_CIFS_ROOT 576 if (ROOT_DEV == Root_CIFS) { 577 if (!mount_cifs_root()) 578 printk(KERN_ERR "VFS: Unable to mount root fs via SMB.\n"); 579 return; 580 } 581 #endif 582 if (ROOT_DEV == 0 && root_device_name && root_fs_names) { 583 if (mount_nodev_root() == 0) 584 return; 585 } 586 #ifdef CONFIG_BLOCK 587 { 588 int err = create_dev("/dev/root", ROOT_DEV); 589 590 if (err < 0) 591 pr_emerg("Failed to create /dev/root: %d\n", err); 592 mount_block_root("/dev/root", root_mountflags); 593 } 594 #endif 595 } 596 597 /* 598 * Prepare the namespace - decide what/where to mount, load ramdisks, etc. 599 */ 600 void __init prepare_namespace(void) 601 { 602 if (root_delay) { 603 printk(KERN_INFO "Waiting %d sec before mounting root device...\n", 604 root_delay); 605 ssleep(root_delay); 606 } 607 608 /* 609 * wait for the known devices to complete their probing 610 * 611 * Note: this is a potential source of long boot delays. 612 * For example, it is not atypical to wait 5 seconds here 613 * for the touchpad of a laptop to initialize. 614 */ 615 wait_for_device_probe(); 616 617 md_run_setup(); 618 619 if (saved_root_name[0]) { 620 root_device_name = saved_root_name; 621 if (!strncmp(root_device_name, "mtd", 3) || 622 !strncmp(root_device_name, "ubi", 3)) { 623 mount_block_root(root_device_name, root_mountflags); 624 goto out; 625 } 626 ROOT_DEV = name_to_dev_t(root_device_name); 627 if (strncmp(root_device_name, "/dev/", 5) == 0) 628 root_device_name += 5; 629 } 630 631 if (initrd_load()) 632 goto out; 633 634 /* wait for any asynchronous scanning to complete */ 635 if ((ROOT_DEV == 0) && root_wait) { 636 printk(KERN_INFO "Waiting for root device %s...\n", 637 saved_root_name); 638 while (driver_probe_done() != 0 || 639 (ROOT_DEV = name_to_dev_t(saved_root_name)) == 0) 640 msleep(5); 641 async_synchronize_full(); 642 } 643 644 mount_root(); 645 out: 646 devtmpfs_mount(); 647 init_mount(".", "/", NULL, MS_MOVE, NULL); 648 init_chroot("."); 649 } 650 651 static bool is_tmpfs; 652 static int rootfs_init_fs_context(struct fs_context *fc) 653 { 654 if (IS_ENABLED(CONFIG_TMPFS) && is_tmpfs) 655 return shmem_init_fs_context(fc); 656 657 return ramfs_init_fs_context(fc); 658 } 659 660 struct file_system_type rootfs_fs_type = { 661 .name = "rootfs", 662 .init_fs_context = rootfs_init_fs_context, 663 .kill_sb = kill_litter_super, 664 }; 665 666 void __init init_rootfs(void) 667 { 668 if (IS_ENABLED(CONFIG_TMPFS) && !saved_root_name[0] && 669 (!root_fs_names || strstr(root_fs_names, "tmpfs"))) 670 is_tmpfs = true; 671 } 672