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