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: 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 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) device number in hexadecimal represents itself 186 * 2) /dev/nfs represents Root_NFS (0xff) 187 * 3) /dev/<disk_name> represents the device number of disk 188 * 4) /dev/<disk_name><decimal> represents the device number 189 * of partition - device number of disk plus the partition number 190 * 5) /dev/<disk_name>p<decimal> - same as the above, that form is 191 * used when disk name of partitioned disk ends on a digit. 192 * 6) PARTUUID=00112233-4455-6677-8899-AABBCCDDEEFF representing the 193 * unique id of a partition if the partition table provides it. 194 * The UUID may be either an EFI/GPT UUID, or refer to an MSDOS 195 * partition using the format SSSSSSSS-PP, where SSSSSSSS is a zero- 196 * filled hex representation of the 32-bit "NT disk signature", and PP 197 * is a zero-filled hex representation of the 1-based partition number. 198 * 7) PARTUUID=<UUID>/PARTNROFF=<int> to select a partition in relation to 199 * a partition with a known unique id. 200 * 8) <major>:<minor> major and minor number of the device separated by 201 * a colon. 202 * 203 * If name doesn't have fall into the categories above, we return (0,0). 204 * block_class is used to check if something is a disk name. If the disk 205 * name contains slashes, the device name has them replaced with 206 * bangs. 207 */ 208 209 dev_t name_to_dev_t(char *name) 210 { 211 char s[32]; 212 char *p; 213 dev_t res = 0; 214 int part; 215 216 #ifdef CONFIG_BLOCK 217 if (strncmp(name, "PARTUUID=", 9) == 0) { 218 name += 9; 219 res = devt_from_partuuid(name); 220 if (!res) 221 goto fail; 222 goto done; 223 } 224 #endif 225 226 if (strncmp(name, "/dev/", 5) != 0) { 227 unsigned maj, min; 228 229 if (sscanf(name, "%u:%u", &maj, &min) == 2) { 230 res = MKDEV(maj, min); 231 if (maj != MAJOR(res) || min != MINOR(res)) 232 goto fail; 233 } else { 234 res = new_decode_dev(simple_strtoul(name, &p, 16)); 235 if (*p) 236 goto fail; 237 } 238 goto done; 239 } 240 241 name += 5; 242 res = Root_NFS; 243 if (strcmp(name, "nfs") == 0) 244 goto done; 245 res = Root_RAM0; 246 if (strcmp(name, "ram") == 0) 247 goto done; 248 249 if (strlen(name) > 31) 250 goto fail; 251 strcpy(s, name); 252 for (p = s; *p; p++) 253 if (*p == '/') 254 *p = '!'; 255 res = blk_lookup_devt(s, 0); 256 if (res) 257 goto done; 258 259 /* 260 * try non-existent, but valid partition, which may only exist 261 * after revalidating the disk, like partitioned md devices 262 */ 263 while (p > s && isdigit(p[-1])) 264 p--; 265 if (p == s || !*p || *p == '0') 266 goto fail; 267 268 /* try disk name without <part number> */ 269 part = simple_strtoul(p, NULL, 10); 270 *p = '\0'; 271 res = blk_lookup_devt(s, part); 272 if (res) 273 goto done; 274 275 /* try disk name without p<part number> */ 276 if (p < s + 2 || !isdigit(p[-2]) || p[-1] != 'p') 277 goto fail; 278 p[-1] = '\0'; 279 res = blk_lookup_devt(s, part); 280 if (res) 281 goto done; 282 283 fail: 284 return 0; 285 done: 286 return res; 287 } 288 289 static int __init root_dev_setup(char *line) 290 { 291 strlcpy(saved_root_name, line, sizeof(saved_root_name)); 292 return 1; 293 } 294 295 __setup("root=", root_dev_setup); 296 297 static int __init rootwait_setup(char *str) 298 { 299 if (*str) 300 return 0; 301 root_wait = 1; 302 return 1; 303 } 304 305 __setup("rootwait", rootwait_setup); 306 307 static char * __initdata root_mount_data; 308 static int __init root_data_setup(char *str) 309 { 310 root_mount_data = str; 311 return 1; 312 } 313 314 static char * __initdata root_fs_names; 315 static int __init fs_names_setup(char *str) 316 { 317 root_fs_names = str; 318 return 1; 319 } 320 321 static unsigned int __initdata root_delay; 322 static int __init root_delay_setup(char *str) 323 { 324 root_delay = simple_strtoul(str, NULL, 0); 325 return 1; 326 } 327 328 __setup("rootflags=", root_data_setup); 329 __setup("rootfstype=", fs_names_setup); 330 __setup("rootdelay=", root_delay_setup); 331 332 static void __init get_fs_names(char *page) 333 { 334 char *s = page; 335 336 if (root_fs_names) { 337 strcpy(page, root_fs_names); 338 while (*s++) { 339 if (s[-1] == ',') 340 s[-1] = '\0'; 341 } 342 } else { 343 int len = get_filesystem_list(page); 344 char *p, *next; 345 346 page[len] = '\0'; 347 for (p = page-1; p; p = next) { 348 next = strchr(++p, '\n'); 349 if (*p++ != '\t') 350 continue; 351 while ((*s++ = *p++) != '\n') 352 ; 353 s[-1] = '\0'; 354 } 355 } 356 *s = '\0'; 357 } 358 359 static int __init do_mount_root(char *name, char *fs, int flags, void *data) 360 { 361 struct super_block *s; 362 int err = sys_mount(name, "/root", fs, flags, data); 363 if (err) 364 return err; 365 366 sys_chdir("/root"); 367 s = current->fs->pwd.dentry->d_sb; 368 ROOT_DEV = s->s_dev; 369 printk(KERN_INFO 370 "VFS: Mounted root (%s filesystem)%s on device %u:%u.\n", 371 s->s_type->name, 372 s->s_flags & MS_RDONLY ? " readonly" : "", 373 MAJOR(ROOT_DEV), MINOR(ROOT_DEV)); 374 return 0; 375 } 376 377 void __init mount_block_root(char *name, int flags) 378 { 379 struct page *page = alloc_page(GFP_KERNEL | 380 __GFP_NOTRACK_FALSE_POSITIVE); 381 char *fs_names = page_address(page); 382 char *p; 383 #ifdef CONFIG_BLOCK 384 char b[BDEVNAME_SIZE]; 385 #else 386 const char *b = name; 387 #endif 388 389 get_fs_names(fs_names); 390 retry: 391 for (p = fs_names; *p; p += strlen(p)+1) { 392 int err = do_mount_root(name, p, flags, root_mount_data); 393 switch (err) { 394 case 0: 395 goto out; 396 case -EACCES: 397 flags |= MS_RDONLY; 398 goto retry; 399 case -EINVAL: 400 continue; 401 } 402 /* 403 * Allow the user to distinguish between failed sys_open 404 * and bad superblock on root device. 405 * and give them a list of the available devices 406 */ 407 #ifdef CONFIG_BLOCK 408 __bdevname(ROOT_DEV, b); 409 #endif 410 printk("VFS: Cannot open root device \"%s\" or %s: error %d\n", 411 root_device_name, b, err); 412 printk("Please append a correct \"root=\" boot option; here are the available partitions:\n"); 413 414 printk_all_partitions(); 415 #ifdef CONFIG_DEBUG_BLOCK_EXT_DEVT 416 printk("DEBUG_BLOCK_EXT_DEVT is enabled, you need to specify " 417 "explicit textual name for \"root=\" boot option.\n"); 418 #endif 419 panic("VFS: Unable to mount root fs on %s", b); 420 } 421 422 printk("List of all partitions:\n"); 423 printk_all_partitions(); 424 printk("No filesystem could mount root, tried: "); 425 for (p = fs_names; *p; p += strlen(p)+1) 426 printk(" %s", p); 427 printk("\n"); 428 #ifdef CONFIG_BLOCK 429 __bdevname(ROOT_DEV, b); 430 #endif 431 panic("VFS: Unable to mount root fs on %s", b); 432 out: 433 put_page(page); 434 } 435 436 #ifdef CONFIG_ROOT_NFS 437 438 #define NFSROOT_TIMEOUT_MIN 5 439 #define NFSROOT_TIMEOUT_MAX 30 440 #define NFSROOT_RETRY_MAX 5 441 442 static int __init mount_nfs_root(void) 443 { 444 char *root_dev, *root_data; 445 unsigned int timeout; 446 int try, err; 447 448 err = nfs_root_data(&root_dev, &root_data); 449 if (err != 0) 450 return 0; 451 452 /* 453 * The server or network may not be ready, so try several 454 * times. Stop after a few tries in case the client wants 455 * to fall back to other boot methods. 456 */ 457 timeout = NFSROOT_TIMEOUT_MIN; 458 for (try = 1; ; try++) { 459 err = do_mount_root(root_dev, "nfs", 460 root_mountflags, root_data); 461 if (err == 0) 462 return 1; 463 if (try > NFSROOT_RETRY_MAX) 464 break; 465 466 /* Wait, in case the server refused us immediately */ 467 ssleep(timeout); 468 timeout <<= 1; 469 if (timeout > NFSROOT_TIMEOUT_MAX) 470 timeout = NFSROOT_TIMEOUT_MAX; 471 } 472 return 0; 473 } 474 #endif 475 476 #if defined(CONFIG_BLK_DEV_RAM) || defined(CONFIG_BLK_DEV_FD) 477 void __init change_floppy(char *fmt, ...) 478 { 479 struct termios termios; 480 char buf[80]; 481 char c; 482 int fd; 483 va_list args; 484 va_start(args, fmt); 485 vsprintf(buf, fmt, args); 486 va_end(args); 487 fd = sys_open("/dev/root", O_RDWR | O_NDELAY, 0); 488 if (fd >= 0) { 489 sys_ioctl(fd, FDEJECT, 0); 490 sys_close(fd); 491 } 492 printk(KERN_NOTICE "VFS: Insert %s and press ENTER\n", buf); 493 fd = sys_open("/dev/console", O_RDWR, 0); 494 if (fd >= 0) { 495 sys_ioctl(fd, TCGETS, (long)&termios); 496 termios.c_lflag &= ~ICANON; 497 sys_ioctl(fd, TCSETSF, (long)&termios); 498 sys_read(fd, &c, 1); 499 termios.c_lflag |= ICANON; 500 sys_ioctl(fd, TCSETSF, (long)&termios); 501 sys_close(fd); 502 } 503 } 504 #endif 505 506 void __init mount_root(void) 507 { 508 #ifdef CONFIG_ROOT_NFS 509 if (ROOT_DEV == Root_NFS) { 510 if (mount_nfs_root()) 511 return; 512 513 printk(KERN_ERR "VFS: Unable to mount root fs via NFS, trying floppy.\n"); 514 ROOT_DEV = Root_FD0; 515 } 516 #endif 517 #ifdef CONFIG_BLK_DEV_FD 518 if (MAJOR(ROOT_DEV) == FLOPPY_MAJOR) { 519 /* rd_doload is 2 for a dual initrd/ramload setup */ 520 if (rd_doload==2) { 521 if (rd_load_disk(1)) { 522 ROOT_DEV = Root_RAM1; 523 root_device_name = NULL; 524 } 525 } else 526 change_floppy("root floppy"); 527 } 528 #endif 529 #ifdef CONFIG_BLOCK 530 create_dev("/dev/root", ROOT_DEV); 531 mount_block_root("/dev/root", root_mountflags); 532 #endif 533 } 534 535 /* 536 * Prepare the namespace - decide what/where to mount, load ramdisks, etc. 537 */ 538 void __init prepare_namespace(void) 539 { 540 int is_floppy; 541 542 if (root_delay) { 543 printk(KERN_INFO "Waiting %d sec before mounting root device...\n", 544 root_delay); 545 ssleep(root_delay); 546 } 547 548 /* 549 * wait for the known devices to complete their probing 550 * 551 * Note: this is a potential source of long boot delays. 552 * For example, it is not atypical to wait 5 seconds here 553 * for the touchpad of a laptop to initialize. 554 */ 555 wait_for_device_probe(); 556 557 md_run_setup(); 558 559 if (saved_root_name[0]) { 560 root_device_name = saved_root_name; 561 if (!strncmp(root_device_name, "mtd", 3) || 562 !strncmp(root_device_name, "ubi", 3)) { 563 mount_block_root(root_device_name, root_mountflags); 564 goto out; 565 } 566 ROOT_DEV = name_to_dev_t(root_device_name); 567 if (strncmp(root_device_name, "/dev/", 5) == 0) 568 root_device_name += 5; 569 } 570 571 if (initrd_load()) 572 goto out; 573 574 /* wait for any asynchronous scanning to complete */ 575 if ((ROOT_DEV == 0) && root_wait) { 576 printk(KERN_INFO "Waiting for root device %s...\n", 577 saved_root_name); 578 while (driver_probe_done() != 0 || 579 (ROOT_DEV = name_to_dev_t(saved_root_name)) == 0) 580 msleep(100); 581 async_synchronize_full(); 582 } 583 584 is_floppy = MAJOR(ROOT_DEV) == FLOPPY_MAJOR; 585 586 if (is_floppy && rd_doload && rd_load_disk(0)) 587 ROOT_DEV = Root_RAM0; 588 589 mount_root(); 590 out: 591 devtmpfs_mount("dev"); 592 sys_mount(".", "/", NULL, MS_MOVE, NULL); 593 sys_chroot("."); 594 } 595 596 static bool is_tmpfs; 597 static struct dentry *rootfs_mount(struct file_system_type *fs_type, 598 int flags, const char *dev_name, void *data) 599 { 600 static unsigned long once; 601 void *fill = ramfs_fill_super; 602 603 if (test_and_set_bit(0, &once)) 604 return ERR_PTR(-ENODEV); 605 606 if (IS_ENABLED(CONFIG_TMPFS) && is_tmpfs) 607 fill = shmem_fill_super; 608 609 return mount_nodev(fs_type, flags, data, fill); 610 } 611 612 static struct file_system_type rootfs_fs_type = { 613 .name = "rootfs", 614 .mount = rootfs_mount, 615 .kill_sb = kill_litter_super, 616 }; 617 618 int __init init_rootfs(void) 619 { 620 int err = register_filesystem(&rootfs_fs_type); 621 622 if (err) 623 return err; 624 625 if (IS_ENABLED(CONFIG_TMPFS) && !saved_root_name[0] && 626 (!root_fs_names || strstr(root_fs_names, "tmpfs"))) { 627 err = shmem_init(); 628 is_tmpfs = true; 629 } else { 630 err = init_ramfs_fs(); 631 } 632 633 if (err) 634 unregister_filesystem(&rootfs_fs_type); 635 636 return err; 637 } 638