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 = ksys_mount(name, "/root", fs, flags, data); 367 if (err) 368 return err; 369 370 ksys_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 char *fs_names = page_address(page); 385 char *p; 386 #ifdef CONFIG_BLOCK 387 char b[BDEVNAME_SIZE]; 388 #else 389 const char *b = name; 390 #endif 391 392 get_fs_names(fs_names); 393 retry: 394 for (p = fs_names; *p; p += strlen(p)+1) { 395 int err = do_mount_root(name, p, flags, root_mount_data); 396 switch (err) { 397 case 0: 398 goto out; 399 case -EACCES: 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 if (!(flags & SB_RDONLY)) { 423 flags |= SB_RDONLY; 424 goto retry; 425 } 426 427 printk("List of all partitions:\n"); 428 printk_all_partitions(); 429 printk("No filesystem could mount root, tried: "); 430 for (p = fs_names; *p; p += strlen(p)+1) 431 printk(" %s", p); 432 printk("\n"); 433 #ifdef CONFIG_BLOCK 434 __bdevname(ROOT_DEV, b); 435 #endif 436 panic("VFS: Unable to mount root fs on %s", b); 437 out: 438 put_page(page); 439 } 440 441 #ifdef CONFIG_ROOT_NFS 442 443 #define NFSROOT_TIMEOUT_MIN 5 444 #define NFSROOT_TIMEOUT_MAX 30 445 #define NFSROOT_RETRY_MAX 5 446 447 static int __init mount_nfs_root(void) 448 { 449 char *root_dev, *root_data; 450 unsigned int timeout; 451 int try, err; 452 453 err = nfs_root_data(&root_dev, &root_data); 454 if (err != 0) 455 return 0; 456 457 /* 458 * The server or network may not be ready, so try several 459 * times. Stop after a few tries in case the client wants 460 * to fall back to other boot methods. 461 */ 462 timeout = NFSROOT_TIMEOUT_MIN; 463 for (try = 1; ; try++) { 464 err = do_mount_root(root_dev, "nfs", 465 root_mountflags, root_data); 466 if (err == 0) 467 return 1; 468 if (try > NFSROOT_RETRY_MAX) 469 break; 470 471 /* Wait, in case the server refused us immediately */ 472 ssleep(timeout); 473 timeout <<= 1; 474 if (timeout > NFSROOT_TIMEOUT_MAX) 475 timeout = NFSROOT_TIMEOUT_MAX; 476 } 477 return 0; 478 } 479 #endif 480 481 #if defined(CONFIG_BLK_DEV_RAM) || defined(CONFIG_BLK_DEV_FD) 482 void __init change_floppy(char *fmt, ...) 483 { 484 struct termios termios; 485 char buf[80]; 486 char c; 487 int fd; 488 va_list args; 489 va_start(args, fmt); 490 vsprintf(buf, fmt, args); 491 va_end(args); 492 fd = ksys_open("/dev/root", O_RDWR | O_NDELAY, 0); 493 if (fd >= 0) { 494 ksys_ioctl(fd, FDEJECT, 0); 495 ksys_close(fd); 496 } 497 printk(KERN_NOTICE "VFS: Insert %s and press ENTER\n", buf); 498 fd = ksys_open("/dev/console", O_RDWR, 0); 499 if (fd >= 0) { 500 ksys_ioctl(fd, TCGETS, (long)&termios); 501 termios.c_lflag &= ~ICANON; 502 ksys_ioctl(fd, TCSETSF, (long)&termios); 503 ksys_read(fd, &c, 1); 504 termios.c_lflag |= ICANON; 505 ksys_ioctl(fd, TCSETSF, (long)&termios); 506 ksys_close(fd); 507 } 508 } 509 #endif 510 511 void __init mount_root(void) 512 { 513 #ifdef CONFIG_ROOT_NFS 514 if (ROOT_DEV == Root_NFS) { 515 if (mount_nfs_root()) 516 return; 517 518 printk(KERN_ERR "VFS: Unable to mount root fs via NFS, trying floppy.\n"); 519 ROOT_DEV = Root_FD0; 520 } 521 #endif 522 #ifdef CONFIG_BLK_DEV_FD 523 if (MAJOR(ROOT_DEV) == FLOPPY_MAJOR) { 524 /* rd_doload is 2 for a dual initrd/ramload setup */ 525 if (rd_doload==2) { 526 if (rd_load_disk(1)) { 527 ROOT_DEV = Root_RAM1; 528 root_device_name = NULL; 529 } 530 } else 531 change_floppy("root floppy"); 532 } 533 #endif 534 #ifdef CONFIG_BLOCK 535 { 536 int err = create_dev("/dev/root", ROOT_DEV); 537 538 if (err < 0) 539 pr_emerg("Failed to create /dev/root: %d\n", err); 540 mount_block_root("/dev/root", root_mountflags); 541 } 542 #endif 543 } 544 545 /* 546 * Prepare the namespace - decide what/where to mount, load ramdisks, etc. 547 */ 548 void __init prepare_namespace(void) 549 { 550 int is_floppy; 551 552 if (root_delay) { 553 printk(KERN_INFO "Waiting %d sec before mounting root device...\n", 554 root_delay); 555 ssleep(root_delay); 556 } 557 558 /* 559 * wait for the known devices to complete their probing 560 * 561 * Note: this is a potential source of long boot delays. 562 * For example, it is not atypical to wait 5 seconds here 563 * for the touchpad of a laptop to initialize. 564 */ 565 wait_for_device_probe(); 566 567 md_run_setup(); 568 569 if (saved_root_name[0]) { 570 root_device_name = saved_root_name; 571 if (!strncmp(root_device_name, "mtd", 3) || 572 !strncmp(root_device_name, "ubi", 3)) { 573 mount_block_root(root_device_name, root_mountflags); 574 goto out; 575 } 576 ROOT_DEV = name_to_dev_t(root_device_name); 577 if (strncmp(root_device_name, "/dev/", 5) == 0) 578 root_device_name += 5; 579 } 580 581 if (initrd_load()) 582 goto out; 583 584 /* wait for any asynchronous scanning to complete */ 585 if ((ROOT_DEV == 0) && root_wait) { 586 printk(KERN_INFO "Waiting for root device %s...\n", 587 saved_root_name); 588 while (driver_probe_done() != 0 || 589 (ROOT_DEV = name_to_dev_t(saved_root_name)) == 0) 590 msleep(5); 591 async_synchronize_full(); 592 } 593 594 is_floppy = MAJOR(ROOT_DEV) == FLOPPY_MAJOR; 595 596 if (is_floppy && rd_doload && rd_load_disk(0)) 597 ROOT_DEV = Root_RAM0; 598 599 mount_root(); 600 out: 601 devtmpfs_mount("dev"); 602 ksys_mount(".", "/", NULL, MS_MOVE, NULL); 603 ksys_chroot("."); 604 } 605 606 static bool is_tmpfs; 607 static struct dentry *rootfs_mount(struct file_system_type *fs_type, 608 int flags, const char *dev_name, void *data) 609 { 610 static unsigned long once; 611 void *fill = ramfs_fill_super; 612 613 if (test_and_set_bit(0, &once)) 614 return ERR_PTR(-ENODEV); 615 616 if (IS_ENABLED(CONFIG_TMPFS) && is_tmpfs) 617 fill = shmem_fill_super; 618 619 return mount_nodev(fs_type, flags, data, fill); 620 } 621 622 static struct file_system_type rootfs_fs_type = { 623 .name = "rootfs", 624 .mount = rootfs_mount, 625 .kill_sb = kill_litter_super, 626 }; 627 628 int __init init_rootfs(void) 629 { 630 int err = register_filesystem(&rootfs_fs_type); 631 632 if (err) 633 return err; 634 635 if (IS_ENABLED(CONFIG_TMPFS) && !saved_root_name[0] && 636 (!root_fs_names || strstr(root_fs_names, "tmpfs"))) { 637 err = shmem_init(); 638 is_tmpfs = true; 639 } else { 640 err = init_ramfs_fs(); 641 } 642 643 if (err) 644 unregister_filesystem(&rootfs_fs_type); 645 646 return err; 647 } 648