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/genhd.h> 12 #include <linux/mount.h> 13 #include <linux/device.h> 14 #include <linux/init.h> 15 #include <linux/fs.h> 16 #include <linux/initrd.h> 17 #include <linux/async.h> 18 #include <linux/fs_struct.h> 19 #include <linux/slab.h> 20 #include <linux/ramfs.h> 21 #include <linux/shmem_fs.h> 22 23 #include <linux/nfs_fs.h> 24 #include <linux/nfs_fs_sb.h> 25 #include <linux/nfs_mount.h> 26 #include <uapi/linux/mount.h> 27 28 #include "do_mounts.h" 29 30 int __initdata rd_doload; /* 1 = load RAM disk, 0 = don't load */ 31 32 int root_mountflags = MS_RDONLY | MS_SILENT; 33 static char * __initdata root_device_name; 34 static char __initdata saved_root_name[64]; 35 static int root_wait; 36 37 dev_t ROOT_DEV; 38 39 static int __init load_ramdisk(char *str) 40 { 41 rd_doload = simple_strtol(str,NULL,0) & 3; 42 return 1; 43 } 44 __setup("load_ramdisk=", load_ramdisk); 45 46 static int __init readonly(char *str) 47 { 48 if (*str) 49 return 0; 50 root_mountflags |= MS_RDONLY; 51 return 1; 52 } 53 54 static int __init readwrite(char *str) 55 { 56 if (*str) 57 return 0; 58 root_mountflags &= ~MS_RDONLY; 59 return 1; 60 } 61 62 __setup("ro", readonly); 63 __setup("rw", readwrite); 64 65 #ifdef CONFIG_BLOCK 66 struct uuidcmp { 67 const char *uuid; 68 int len; 69 }; 70 71 /** 72 * match_dev_by_uuid - callback for finding a partition using its uuid 73 * @dev: device passed in by the caller 74 * @data: opaque pointer to the desired struct uuidcmp to match 75 * 76 * Returns 1 if the device matches, and 0 otherwise. 77 */ 78 static int match_dev_by_uuid(struct device *dev, const void *data) 79 { 80 const struct uuidcmp *cmp = data; 81 struct hd_struct *part = dev_to_part(dev); 82 83 if (!part->info) 84 goto no_match; 85 86 if (strncasecmp(cmp->uuid, part->info->uuid, cmp->len)) 87 goto no_match; 88 89 return 1; 90 no_match: 91 return 0; 92 } 93 94 95 /** 96 * devt_from_partuuid - looks up the dev_t of a partition by its UUID 97 * @uuid_str: char array containing ascii UUID 98 * 99 * The function will return the first partition which contains a matching 100 * UUID value in its partition_meta_info struct. This does not search 101 * by filesystem UUIDs. 102 * 103 * If @uuid_str is followed by a "/PARTNROFF=%d", then the number will be 104 * extracted and used as an offset from the partition identified by the UUID. 105 * 106 * Returns the matching dev_t on success or 0 on failure. 107 */ 108 static dev_t devt_from_partuuid(const char *uuid_str) 109 { 110 dev_t res = 0; 111 struct uuidcmp cmp; 112 struct device *dev = NULL; 113 struct gendisk *disk; 114 struct hd_struct *part; 115 int offset = 0; 116 bool clear_root_wait = false; 117 char *slash; 118 119 cmp.uuid = uuid_str; 120 121 slash = strchr(uuid_str, '/'); 122 /* Check for optional partition number offset attributes. */ 123 if (slash) { 124 char c = 0; 125 /* Explicitly fail on poor PARTUUID syntax. */ 126 if (sscanf(slash + 1, 127 "PARTNROFF=%d%c", &offset, &c) != 1) { 128 clear_root_wait = true; 129 goto done; 130 } 131 cmp.len = slash - uuid_str; 132 } else { 133 cmp.len = strlen(uuid_str); 134 } 135 136 if (!cmp.len) { 137 clear_root_wait = true; 138 goto done; 139 } 140 141 dev = class_find_device(&block_class, NULL, &cmp, 142 &match_dev_by_uuid); 143 if (!dev) 144 goto done; 145 146 res = dev->devt; 147 148 /* Attempt to find the partition by offset. */ 149 if (!offset) 150 goto no_offset; 151 152 res = 0; 153 disk = part_to_disk(dev_to_part(dev)); 154 part = disk_get_part(disk, dev_to_part(dev)->partno + offset); 155 if (part) { 156 res = part_devt(part); 157 put_device(part_to_dev(part)); 158 } 159 160 no_offset: 161 put_device(dev); 162 done: 163 if (clear_root_wait) { 164 pr_err("VFS: PARTUUID= is invalid.\n" 165 "Expected PARTUUID=<valid-uuid-id>[/PARTNROFF=%%d]\n"); 166 if (root_wait) 167 pr_err("Disabling rootwait; root= is invalid.\n"); 168 root_wait = 0; 169 } 170 return res; 171 } 172 173 /** 174 * match_dev_by_label - callback for finding a partition using its label 175 * @dev: device passed in by the caller 176 * @data: opaque pointer to the label to match 177 * 178 * Returns 1 if the device matches, and 0 otherwise. 179 */ 180 static int match_dev_by_label(struct device *dev, const void *data) 181 { 182 const char *label = data; 183 struct hd_struct *part = dev_to_part(dev); 184 185 if (part->info && !strcmp(label, part->info->volname)) 186 return 1; 187 188 return 0; 189 } 190 #endif 191 192 /* 193 * Convert a name into device number. We accept the following variants: 194 * 195 * 1) <hex_major><hex_minor> device number in hexadecimal represents itself 196 * no leading 0x, for example b302. 197 * 2) /dev/nfs represents Root_NFS (0xff) 198 * 3) /dev/<disk_name> represents the device number of disk 199 * 4) /dev/<disk_name><decimal> represents the device number 200 * of partition - device number of disk plus the partition number 201 * 5) /dev/<disk_name>p<decimal> - same as the above, that form is 202 * used when disk name of partitioned disk ends on a digit. 203 * 6) PARTUUID=00112233-4455-6677-8899-AABBCCDDEEFF representing the 204 * unique id of a partition if the partition table provides it. 205 * The UUID may be either an EFI/GPT UUID, or refer to an MSDOS 206 * partition using the format SSSSSSSS-PP, where SSSSSSSS is a zero- 207 * filled hex representation of the 32-bit "NT disk signature", and PP 208 * is a zero-filled hex representation of the 1-based partition number. 209 * 7) PARTUUID=<UUID>/PARTNROFF=<int> to select a partition in relation to 210 * a partition with a known unique id. 211 * 8) <major>:<minor> major and minor number of the device separated by 212 * a colon. 213 * 9) PARTLABEL=<name> with name being the GPT partition label. 214 * MSDOS partitions do not support labels! 215 * 10) /dev/cifs represents Root_CIFS (0xfe) 216 * 217 * If name doesn't have fall into the categories above, we return (0,0). 218 * block_class is used to check if something is a disk name. If the disk 219 * name contains slashes, the device name has them replaced with 220 * bangs. 221 */ 222 223 dev_t name_to_dev_t(const char *name) 224 { 225 char s[32]; 226 char *p; 227 dev_t res = 0; 228 int part; 229 230 #ifdef CONFIG_BLOCK 231 if (strncmp(name, "PARTUUID=", 9) == 0) { 232 name += 9; 233 res = devt_from_partuuid(name); 234 if (!res) 235 goto fail; 236 goto done; 237 } else if (strncmp(name, "PARTLABEL=", 10) == 0) { 238 struct device *dev; 239 240 dev = class_find_device(&block_class, NULL, name + 10, 241 &match_dev_by_label); 242 if (!dev) 243 goto fail; 244 245 res = dev->devt; 246 put_device(dev); 247 goto done; 248 } 249 #endif 250 251 if (strncmp(name, "/dev/", 5) != 0) { 252 unsigned maj, min, offset; 253 char dummy; 254 255 if ((sscanf(name, "%u:%u%c", &maj, &min, &dummy) == 2) || 256 (sscanf(name, "%u:%u:%u:%c", &maj, &min, &offset, &dummy) == 3)) { 257 res = MKDEV(maj, min); 258 if (maj != MAJOR(res) || min != MINOR(res)) 259 goto fail; 260 } else { 261 res = new_decode_dev(simple_strtoul(name, &p, 16)); 262 if (*p) 263 goto fail; 264 } 265 goto done; 266 } 267 268 name += 5; 269 res = Root_NFS; 270 if (strcmp(name, "nfs") == 0) 271 goto done; 272 res = Root_CIFS; 273 if (strcmp(name, "cifs") == 0) 274 goto done; 275 res = Root_RAM0; 276 if (strcmp(name, "ram") == 0) 277 goto done; 278 279 if (strlen(name) > 31) 280 goto fail; 281 strcpy(s, name); 282 for (p = s; *p; p++) 283 if (*p == '/') 284 *p = '!'; 285 res = blk_lookup_devt(s, 0); 286 if (res) 287 goto done; 288 289 /* 290 * try non-existent, but valid partition, which may only exist 291 * after revalidating the disk, like partitioned md devices 292 */ 293 while (p > s && isdigit(p[-1])) 294 p--; 295 if (p == s || !*p || *p == '0') 296 goto fail; 297 298 /* try disk name without <part number> */ 299 part = simple_strtoul(p, NULL, 10); 300 *p = '\0'; 301 res = blk_lookup_devt(s, part); 302 if (res) 303 goto done; 304 305 /* try disk name without p<part number> */ 306 if (p < s + 2 || !isdigit(p[-2]) || p[-1] != 'p') 307 goto fail; 308 p[-1] = '\0'; 309 res = blk_lookup_devt(s, part); 310 if (res) 311 goto done; 312 313 fail: 314 return 0; 315 done: 316 return res; 317 } 318 EXPORT_SYMBOL_GPL(name_to_dev_t); 319 320 static int __init root_dev_setup(char *line) 321 { 322 strlcpy(saved_root_name, line, sizeof(saved_root_name)); 323 return 1; 324 } 325 326 __setup("root=", root_dev_setup); 327 328 static int __init rootwait_setup(char *str) 329 { 330 if (*str) 331 return 0; 332 root_wait = 1; 333 return 1; 334 } 335 336 __setup("rootwait", rootwait_setup); 337 338 static char * __initdata root_mount_data; 339 static int __init root_data_setup(char *str) 340 { 341 root_mount_data = str; 342 return 1; 343 } 344 345 static char * __initdata root_fs_names; 346 static int __init fs_names_setup(char *str) 347 { 348 root_fs_names = str; 349 return 1; 350 } 351 352 static unsigned int __initdata root_delay; 353 static int __init root_delay_setup(char *str) 354 { 355 root_delay = simple_strtoul(str, NULL, 0); 356 return 1; 357 } 358 359 __setup("rootflags=", root_data_setup); 360 __setup("rootfstype=", fs_names_setup); 361 __setup("rootdelay=", root_delay_setup); 362 363 static void __init get_fs_names(char *page) 364 { 365 char *s = page; 366 367 if (root_fs_names) { 368 strcpy(page, root_fs_names); 369 while (*s++) { 370 if (s[-1] == ',') 371 s[-1] = '\0'; 372 } 373 } else { 374 int len = get_filesystem_list(page); 375 char *p, *next; 376 377 page[len] = '\0'; 378 for (p = page-1; p; p = next) { 379 next = strchr(++p, '\n'); 380 if (*p++ != '\t') 381 continue; 382 while ((*s++ = *p++) != '\n') 383 ; 384 s[-1] = '\0'; 385 } 386 } 387 *s = '\0'; 388 } 389 390 static int __init do_mount_root(char *name, char *fs, int flags, void *data) 391 { 392 struct super_block *s; 393 int err = ksys_mount(name, "/root", fs, flags, data); 394 if (err) 395 return err; 396 397 ksys_chdir("/root"); 398 s = current->fs->pwd.dentry->d_sb; 399 ROOT_DEV = s->s_dev; 400 printk(KERN_INFO 401 "VFS: Mounted root (%s filesystem)%s on device %u:%u.\n", 402 s->s_type->name, 403 sb_rdonly(s) ? " readonly" : "", 404 MAJOR(ROOT_DEV), MINOR(ROOT_DEV)); 405 return 0; 406 } 407 408 void __init mount_block_root(char *name, int flags) 409 { 410 struct page *page = alloc_page(GFP_KERNEL); 411 char *fs_names = page_address(page); 412 char *p; 413 #ifdef CONFIG_BLOCK 414 char b[BDEVNAME_SIZE]; 415 #else 416 const char *b = name; 417 #endif 418 419 get_fs_names(fs_names); 420 retry: 421 for (p = fs_names; *p; p += strlen(p)+1) { 422 int err = do_mount_root(name, p, flags, root_mount_data); 423 switch (err) { 424 case 0: 425 goto out; 426 case -EACCES: 427 case -EINVAL: 428 continue; 429 } 430 /* 431 * Allow the user to distinguish between failed sys_open 432 * and bad superblock on root device. 433 * and give them a list of the available devices 434 */ 435 #ifdef CONFIG_BLOCK 436 __bdevname(ROOT_DEV, b); 437 #endif 438 printk("VFS: Cannot open root device \"%s\" or %s: error %d\n", 439 root_device_name, b, err); 440 printk("Please append a correct \"root=\" boot option; here are the available partitions:\n"); 441 442 printk_all_partitions(); 443 #ifdef CONFIG_DEBUG_BLOCK_EXT_DEVT 444 printk("DEBUG_BLOCK_EXT_DEVT is enabled, you need to specify " 445 "explicit textual name for \"root=\" boot option.\n"); 446 #endif 447 panic("VFS: Unable to mount root fs on %s", b); 448 } 449 if (!(flags & SB_RDONLY)) { 450 flags |= SB_RDONLY; 451 goto retry; 452 } 453 454 printk("List of all partitions:\n"); 455 printk_all_partitions(); 456 printk("No filesystem could mount root, tried: "); 457 for (p = fs_names; *p; p += strlen(p)+1) 458 printk(" %s", p); 459 printk("\n"); 460 #ifdef CONFIG_BLOCK 461 __bdevname(ROOT_DEV, b); 462 #endif 463 panic("VFS: Unable to mount root fs on %s", b); 464 out: 465 put_page(page); 466 } 467 468 #ifdef CONFIG_ROOT_NFS 469 470 #define NFSROOT_TIMEOUT_MIN 5 471 #define NFSROOT_TIMEOUT_MAX 30 472 #define NFSROOT_RETRY_MAX 5 473 474 static int __init mount_nfs_root(void) 475 { 476 char *root_dev, *root_data; 477 unsigned int timeout; 478 int try, err; 479 480 err = nfs_root_data(&root_dev, &root_data); 481 if (err != 0) 482 return 0; 483 484 /* 485 * The server or network may not be ready, so try several 486 * times. Stop after a few tries in case the client wants 487 * to fall back to other boot methods. 488 */ 489 timeout = NFSROOT_TIMEOUT_MIN; 490 for (try = 1; ; try++) { 491 err = do_mount_root(root_dev, "nfs", 492 root_mountflags, root_data); 493 if (err == 0) 494 return 1; 495 if (try > NFSROOT_RETRY_MAX) 496 break; 497 498 /* Wait, in case the server refused us immediately */ 499 ssleep(timeout); 500 timeout <<= 1; 501 if (timeout > NFSROOT_TIMEOUT_MAX) 502 timeout = NFSROOT_TIMEOUT_MAX; 503 } 504 return 0; 505 } 506 #endif 507 508 #ifdef CONFIG_CIFS_ROOT 509 510 extern int cifs_root_data(char **dev, char **opts); 511 512 #define CIFSROOT_TIMEOUT_MIN 5 513 #define CIFSROOT_TIMEOUT_MAX 30 514 #define CIFSROOT_RETRY_MAX 5 515 516 static int __init mount_cifs_root(void) 517 { 518 char *root_dev, *root_data; 519 unsigned int timeout; 520 int try, err; 521 522 err = cifs_root_data(&root_dev, &root_data); 523 if (err != 0) 524 return 0; 525 526 timeout = CIFSROOT_TIMEOUT_MIN; 527 for (try = 1; ; try++) { 528 err = do_mount_root(root_dev, "cifs", root_mountflags, 529 root_data); 530 if (err == 0) 531 return 1; 532 if (try > CIFSROOT_RETRY_MAX) 533 break; 534 535 ssleep(timeout); 536 timeout <<= 1; 537 if (timeout > CIFSROOT_TIMEOUT_MAX) 538 timeout = CIFSROOT_TIMEOUT_MAX; 539 } 540 return 0; 541 } 542 #endif 543 544 #if defined(CONFIG_BLK_DEV_RAM) || defined(CONFIG_BLK_DEV_FD) 545 void __init change_floppy(char *fmt, ...) 546 { 547 struct termios termios; 548 char buf[80]; 549 char c; 550 int fd; 551 va_list args; 552 va_start(args, fmt); 553 vsprintf(buf, fmt, args); 554 va_end(args); 555 fd = ksys_open("/dev/root", O_RDWR | O_NDELAY, 0); 556 if (fd >= 0) { 557 ksys_ioctl(fd, FDEJECT, 0); 558 ksys_close(fd); 559 } 560 printk(KERN_NOTICE "VFS: Insert %s and press ENTER\n", buf); 561 fd = ksys_open("/dev/console", O_RDWR, 0); 562 if (fd >= 0) { 563 ksys_ioctl(fd, TCGETS, (long)&termios); 564 termios.c_lflag &= ~ICANON; 565 ksys_ioctl(fd, TCSETSF, (long)&termios); 566 ksys_read(fd, &c, 1); 567 termios.c_lflag |= ICANON; 568 ksys_ioctl(fd, TCSETSF, (long)&termios); 569 ksys_close(fd); 570 } 571 } 572 #endif 573 574 void __init mount_root(void) 575 { 576 #ifdef CONFIG_ROOT_NFS 577 if (ROOT_DEV == Root_NFS) { 578 if (mount_nfs_root()) 579 return; 580 581 printk(KERN_ERR "VFS: Unable to mount root fs via NFS, trying floppy.\n"); 582 ROOT_DEV = Root_FD0; 583 } 584 #endif 585 #ifdef CONFIG_CIFS_ROOT 586 if (ROOT_DEV == Root_CIFS) { 587 if (mount_cifs_root()) 588 return; 589 590 printk(KERN_ERR "VFS: Unable to mount root fs via SMB, trying floppy.\n"); 591 ROOT_DEV = Root_FD0; 592 } 593 #endif 594 #ifdef CONFIG_BLK_DEV_FD 595 if (MAJOR(ROOT_DEV) == FLOPPY_MAJOR) { 596 /* rd_doload is 2 for a dual initrd/ramload setup */ 597 if (rd_doload==2) { 598 if (rd_load_disk(1)) { 599 ROOT_DEV = Root_RAM1; 600 root_device_name = NULL; 601 } 602 } else 603 change_floppy("root floppy"); 604 } 605 #endif 606 #ifdef CONFIG_BLOCK 607 { 608 int err = create_dev("/dev/root", ROOT_DEV); 609 610 if (err < 0) 611 pr_emerg("Failed to create /dev/root: %d\n", err); 612 mount_block_root("/dev/root", root_mountflags); 613 } 614 #endif 615 } 616 617 /* 618 * Prepare the namespace - decide what/where to mount, load ramdisks, etc. 619 */ 620 void __init prepare_namespace(void) 621 { 622 int is_floppy; 623 624 if (root_delay) { 625 printk(KERN_INFO "Waiting %d sec before mounting root device...\n", 626 root_delay); 627 ssleep(root_delay); 628 } 629 630 /* 631 * wait for the known devices to complete their probing 632 * 633 * Note: this is a potential source of long boot delays. 634 * For example, it is not atypical to wait 5 seconds here 635 * for the touchpad of a laptop to initialize. 636 */ 637 wait_for_device_probe(); 638 639 md_run_setup(); 640 641 if (saved_root_name[0]) { 642 root_device_name = saved_root_name; 643 if (!strncmp(root_device_name, "mtd", 3) || 644 !strncmp(root_device_name, "ubi", 3)) { 645 mount_block_root(root_device_name, root_mountflags); 646 goto out; 647 } 648 ROOT_DEV = name_to_dev_t(root_device_name); 649 if (strncmp(root_device_name, "/dev/", 5) == 0) 650 root_device_name += 5; 651 } 652 653 if (initrd_load()) 654 goto out; 655 656 /* wait for any asynchronous scanning to complete */ 657 if ((ROOT_DEV == 0) && root_wait) { 658 printk(KERN_INFO "Waiting for root device %s...\n", 659 saved_root_name); 660 while (driver_probe_done() != 0 || 661 (ROOT_DEV = name_to_dev_t(saved_root_name)) == 0) 662 msleep(5); 663 async_synchronize_full(); 664 } 665 666 is_floppy = MAJOR(ROOT_DEV) == FLOPPY_MAJOR; 667 668 if (is_floppy && rd_doload && rd_load_disk(0)) 669 ROOT_DEV = Root_RAM0; 670 671 mount_root(); 672 out: 673 devtmpfs_mount("dev"); 674 ksys_mount(".", "/", NULL, MS_MOVE, NULL); 675 ksys_chroot("."); 676 } 677 678 static bool is_tmpfs; 679 static int rootfs_init_fs_context(struct fs_context *fc) 680 { 681 if (IS_ENABLED(CONFIG_TMPFS) && is_tmpfs) 682 return shmem_init_fs_context(fc); 683 684 return ramfs_init_fs_context(fc); 685 } 686 687 struct file_system_type rootfs_fs_type = { 688 .name = "rootfs", 689 .init_fs_context = rootfs_init_fs_context, 690 .kill_sb = kill_litter_super, 691 }; 692 693 void __init init_rootfs(void) 694 { 695 if (IS_ENABLED(CONFIG_TMPFS) && !saved_root_name[0] && 696 (!root_fs_names || strstr(root_fs_names, "tmpfs"))) 697 is_tmpfs = true; 698 } 699