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 * 216 * If name doesn't have fall into the categories above, we return (0,0). 217 * block_class is used to check if something is a disk name. If the disk 218 * name contains slashes, the device name has them replaced with 219 * bangs. 220 */ 221 222 dev_t name_to_dev_t(const char *name) 223 { 224 char s[32]; 225 char *p; 226 dev_t res = 0; 227 int part; 228 229 #ifdef CONFIG_BLOCK 230 if (strncmp(name, "PARTUUID=", 9) == 0) { 231 name += 9; 232 res = devt_from_partuuid(name); 233 if (!res) 234 goto fail; 235 goto done; 236 } else if (strncmp(name, "PARTLABEL=", 10) == 0) { 237 struct device *dev; 238 239 dev = class_find_device(&block_class, NULL, name + 10, 240 &match_dev_by_label); 241 if (!dev) 242 goto fail; 243 244 res = dev->devt; 245 put_device(dev); 246 goto done; 247 } 248 #endif 249 250 if (strncmp(name, "/dev/", 5) != 0) { 251 unsigned maj, min, offset; 252 char dummy; 253 254 if ((sscanf(name, "%u:%u%c", &maj, &min, &dummy) == 2) || 255 (sscanf(name, "%u:%u:%u:%c", &maj, &min, &offset, &dummy) == 3)) { 256 res = MKDEV(maj, min); 257 if (maj != MAJOR(res) || min != MINOR(res)) 258 goto fail; 259 } else { 260 res = new_decode_dev(simple_strtoul(name, &p, 16)); 261 if (*p) 262 goto fail; 263 } 264 goto done; 265 } 266 267 name += 5; 268 res = Root_NFS; 269 if (strcmp(name, "nfs") == 0) 270 goto done; 271 res = Root_RAM0; 272 if (strcmp(name, "ram") == 0) 273 goto done; 274 275 if (strlen(name) > 31) 276 goto fail; 277 strcpy(s, name); 278 for (p = s; *p; p++) 279 if (*p == '/') 280 *p = '!'; 281 res = blk_lookup_devt(s, 0); 282 if (res) 283 goto done; 284 285 /* 286 * try non-existent, but valid partition, which may only exist 287 * after revalidating the disk, like partitioned md devices 288 */ 289 while (p > s && isdigit(p[-1])) 290 p--; 291 if (p == s || !*p || *p == '0') 292 goto fail; 293 294 /* try disk name without <part number> */ 295 part = simple_strtoul(p, NULL, 10); 296 *p = '\0'; 297 res = blk_lookup_devt(s, part); 298 if (res) 299 goto done; 300 301 /* try disk name without p<part number> */ 302 if (p < s + 2 || !isdigit(p[-2]) || p[-1] != 'p') 303 goto fail; 304 p[-1] = '\0'; 305 res = blk_lookup_devt(s, part); 306 if (res) 307 goto done; 308 309 fail: 310 return 0; 311 done: 312 return res; 313 } 314 EXPORT_SYMBOL_GPL(name_to_dev_t); 315 316 static int __init root_dev_setup(char *line) 317 { 318 strlcpy(saved_root_name, line, sizeof(saved_root_name)); 319 return 1; 320 } 321 322 __setup("root=", root_dev_setup); 323 324 static int __init rootwait_setup(char *str) 325 { 326 if (*str) 327 return 0; 328 root_wait = 1; 329 return 1; 330 } 331 332 __setup("rootwait", rootwait_setup); 333 334 static char * __initdata root_mount_data; 335 static int __init root_data_setup(char *str) 336 { 337 root_mount_data = str; 338 return 1; 339 } 340 341 static char * __initdata root_fs_names; 342 static int __init fs_names_setup(char *str) 343 { 344 root_fs_names = str; 345 return 1; 346 } 347 348 static unsigned int __initdata root_delay; 349 static int __init root_delay_setup(char *str) 350 { 351 root_delay = simple_strtoul(str, NULL, 0); 352 return 1; 353 } 354 355 __setup("rootflags=", root_data_setup); 356 __setup("rootfstype=", fs_names_setup); 357 __setup("rootdelay=", root_delay_setup); 358 359 static void __init get_fs_names(char *page) 360 { 361 char *s = page; 362 363 if (root_fs_names) { 364 strcpy(page, root_fs_names); 365 while (*s++) { 366 if (s[-1] == ',') 367 s[-1] = '\0'; 368 } 369 } else { 370 int len = get_filesystem_list(page); 371 char *p, *next; 372 373 page[len] = '\0'; 374 for (p = page-1; p; p = next) { 375 next = strchr(++p, '\n'); 376 if (*p++ != '\t') 377 continue; 378 while ((*s++ = *p++) != '\n') 379 ; 380 s[-1] = '\0'; 381 } 382 } 383 *s = '\0'; 384 } 385 386 static int __init do_mount_root(char *name, char *fs, int flags, void *data) 387 { 388 struct super_block *s; 389 int err = ksys_mount(name, "/root", fs, flags, data); 390 if (err) 391 return err; 392 393 ksys_chdir("/root"); 394 s = current->fs->pwd.dentry->d_sb; 395 ROOT_DEV = s->s_dev; 396 printk(KERN_INFO 397 "VFS: Mounted root (%s filesystem)%s on device %u:%u.\n", 398 s->s_type->name, 399 sb_rdonly(s) ? " readonly" : "", 400 MAJOR(ROOT_DEV), MINOR(ROOT_DEV)); 401 return 0; 402 } 403 404 void __init mount_block_root(char *name, int flags) 405 { 406 struct page *page = alloc_page(GFP_KERNEL); 407 char *fs_names = page_address(page); 408 char *p; 409 #ifdef CONFIG_BLOCK 410 char b[BDEVNAME_SIZE]; 411 #else 412 const char *b = name; 413 #endif 414 415 get_fs_names(fs_names); 416 retry: 417 for (p = fs_names; *p; p += strlen(p)+1) { 418 int err = do_mount_root(name, p, flags, root_mount_data); 419 switch (err) { 420 case 0: 421 goto out; 422 case -EACCES: 423 case -EINVAL: 424 continue; 425 } 426 /* 427 * Allow the user to distinguish between failed sys_open 428 * and bad superblock on root device. 429 * and give them a list of the available devices 430 */ 431 #ifdef CONFIG_BLOCK 432 __bdevname(ROOT_DEV, b); 433 #endif 434 printk("VFS: Cannot open root device \"%s\" or %s: error %d\n", 435 root_device_name, b, err); 436 printk("Please append a correct \"root=\" boot option; here are the available partitions:\n"); 437 438 printk_all_partitions(); 439 #ifdef CONFIG_DEBUG_BLOCK_EXT_DEVT 440 printk("DEBUG_BLOCK_EXT_DEVT is enabled, you need to specify " 441 "explicit textual name for \"root=\" boot option.\n"); 442 #endif 443 panic("VFS: Unable to mount root fs on %s", b); 444 } 445 if (!(flags & SB_RDONLY)) { 446 flags |= SB_RDONLY; 447 goto retry; 448 } 449 450 printk("List of all partitions:\n"); 451 printk_all_partitions(); 452 printk("No filesystem could mount root, tried: "); 453 for (p = fs_names; *p; p += strlen(p)+1) 454 printk(" %s", p); 455 printk("\n"); 456 #ifdef CONFIG_BLOCK 457 __bdevname(ROOT_DEV, b); 458 #endif 459 panic("VFS: Unable to mount root fs on %s", b); 460 out: 461 put_page(page); 462 } 463 464 #ifdef CONFIG_ROOT_NFS 465 466 #define NFSROOT_TIMEOUT_MIN 5 467 #define NFSROOT_TIMEOUT_MAX 30 468 #define NFSROOT_RETRY_MAX 5 469 470 static int __init mount_nfs_root(void) 471 { 472 char *root_dev, *root_data; 473 unsigned int timeout; 474 int try, err; 475 476 err = nfs_root_data(&root_dev, &root_data); 477 if (err != 0) 478 return 0; 479 480 /* 481 * The server or network may not be ready, so try several 482 * times. Stop after a few tries in case the client wants 483 * to fall back to other boot methods. 484 */ 485 timeout = NFSROOT_TIMEOUT_MIN; 486 for (try = 1; ; try++) { 487 err = do_mount_root(root_dev, "nfs", 488 root_mountflags, root_data); 489 if (err == 0) 490 return 1; 491 if (try > NFSROOT_RETRY_MAX) 492 break; 493 494 /* Wait, in case the server refused us immediately */ 495 ssleep(timeout); 496 timeout <<= 1; 497 if (timeout > NFSROOT_TIMEOUT_MAX) 498 timeout = NFSROOT_TIMEOUT_MAX; 499 } 500 return 0; 501 } 502 #endif 503 504 #if defined(CONFIG_BLK_DEV_RAM) || defined(CONFIG_BLK_DEV_FD) 505 void __init change_floppy(char *fmt, ...) 506 { 507 struct termios termios; 508 char buf[80]; 509 char c; 510 int fd; 511 va_list args; 512 va_start(args, fmt); 513 vsprintf(buf, fmt, args); 514 va_end(args); 515 fd = ksys_open("/dev/root", O_RDWR | O_NDELAY, 0); 516 if (fd >= 0) { 517 ksys_ioctl(fd, FDEJECT, 0); 518 ksys_close(fd); 519 } 520 printk(KERN_NOTICE "VFS: Insert %s and press ENTER\n", buf); 521 fd = ksys_open("/dev/console", O_RDWR, 0); 522 if (fd >= 0) { 523 ksys_ioctl(fd, TCGETS, (long)&termios); 524 termios.c_lflag &= ~ICANON; 525 ksys_ioctl(fd, TCSETSF, (long)&termios); 526 ksys_read(fd, &c, 1); 527 termios.c_lflag |= ICANON; 528 ksys_ioctl(fd, TCSETSF, (long)&termios); 529 ksys_close(fd); 530 } 531 } 532 #endif 533 534 void __init mount_root(void) 535 { 536 #ifdef CONFIG_ROOT_NFS 537 if (ROOT_DEV == Root_NFS) { 538 if (mount_nfs_root()) 539 return; 540 541 printk(KERN_ERR "VFS: Unable to mount root fs via NFS, trying floppy.\n"); 542 ROOT_DEV = Root_FD0; 543 } 544 #endif 545 #ifdef CONFIG_BLK_DEV_FD 546 if (MAJOR(ROOT_DEV) == FLOPPY_MAJOR) { 547 /* rd_doload is 2 for a dual initrd/ramload setup */ 548 if (rd_doload==2) { 549 if (rd_load_disk(1)) { 550 ROOT_DEV = Root_RAM1; 551 root_device_name = NULL; 552 } 553 } else 554 change_floppy("root floppy"); 555 } 556 #endif 557 #ifdef CONFIG_BLOCK 558 { 559 int err = create_dev("/dev/root", ROOT_DEV); 560 561 if (err < 0) 562 pr_emerg("Failed to create /dev/root: %d\n", err); 563 mount_block_root("/dev/root", root_mountflags); 564 } 565 #endif 566 } 567 568 /* 569 * Prepare the namespace - decide what/where to mount, load ramdisks, etc. 570 */ 571 void __init prepare_namespace(void) 572 { 573 int is_floppy; 574 575 if (root_delay) { 576 printk(KERN_INFO "Waiting %d sec before mounting root device...\n", 577 root_delay); 578 ssleep(root_delay); 579 } 580 581 /* 582 * wait for the known devices to complete their probing 583 * 584 * Note: this is a potential source of long boot delays. 585 * For example, it is not atypical to wait 5 seconds here 586 * for the touchpad of a laptop to initialize. 587 */ 588 wait_for_device_probe(); 589 590 md_run_setup(); 591 592 if (saved_root_name[0]) { 593 root_device_name = saved_root_name; 594 if (!strncmp(root_device_name, "mtd", 3) || 595 !strncmp(root_device_name, "ubi", 3)) { 596 mount_block_root(root_device_name, root_mountflags); 597 goto out; 598 } 599 ROOT_DEV = name_to_dev_t(root_device_name); 600 if (strncmp(root_device_name, "/dev/", 5) == 0) 601 root_device_name += 5; 602 } 603 604 if (initrd_load()) 605 goto out; 606 607 /* wait for any asynchronous scanning to complete */ 608 if ((ROOT_DEV == 0) && root_wait) { 609 printk(KERN_INFO "Waiting for root device %s...\n", 610 saved_root_name); 611 while (driver_probe_done() != 0 || 612 (ROOT_DEV = name_to_dev_t(saved_root_name)) == 0) 613 msleep(5); 614 async_synchronize_full(); 615 } 616 617 is_floppy = MAJOR(ROOT_DEV) == FLOPPY_MAJOR; 618 619 if (is_floppy && rd_doload && rd_load_disk(0)) 620 ROOT_DEV = Root_RAM0; 621 622 mount_root(); 623 out: 624 devtmpfs_mount("dev"); 625 ksys_mount(".", "/", NULL, MS_MOVE, NULL); 626 ksys_chroot("."); 627 } 628 629 static bool is_tmpfs; 630 static int rootfs_init_fs_context(struct fs_context *fc) 631 { 632 if (IS_ENABLED(CONFIG_TMPFS) && is_tmpfs) 633 return shmem_init_fs_context(fc); 634 635 return ramfs_init_fs_context(fc); 636 } 637 638 struct file_system_type rootfs_fs_type = { 639 .name = "rootfs", 640 .init_fs_context = rootfs_init_fs_context, 641 .kill_sb = kill_litter_super, 642 }; 643 644 void __init init_rootfs(void) 645 { 646 if (IS_ENABLED(CONFIG_TMPFS) && !saved_root_name[0] && 647 (!root_fs_names || strstr(root_fs_names, "tmpfs"))) 648 is_tmpfs = true; 649 } 650