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/mount.h> 12 #include <linux/device.h> 13 #include <linux/init.h> 14 #include <linux/fs.h> 15 #include <linux/initrd.h> 16 #include <linux/async.h> 17 #include <linux/fs_struct.h> 18 #include <linux/slab.h> 19 #include <linux/ramfs.h> 20 #include <linux/shmem_fs.h> 21 #include <linux/ktime.h> 22 23 #include <linux/nfs_fs.h> 24 #include <linux/nfs_fs_sb.h> 25 #include <linux/nfs_mount.h> 26 #include <linux/raid/detect.h> 27 #include <uapi/linux/mount.h> 28 29 #include "do_mounts.h" 30 31 int root_mountflags = MS_RDONLY | MS_SILENT; 32 static char __initdata saved_root_name[64]; 33 static int root_wait; 34 35 dev_t ROOT_DEV; 36 37 static int __init load_ramdisk(char *str) 38 { 39 pr_warn("ignoring the deprecated load_ramdisk= option\n"); 40 return 1; 41 } 42 __setup("load_ramdisk=", load_ramdisk); 43 44 static int __init readonly(char *str) 45 { 46 if (*str) 47 return 0; 48 root_mountflags |= MS_RDONLY; 49 return 1; 50 } 51 52 static int __init readwrite(char *str) 53 { 54 if (*str) 55 return 0; 56 root_mountflags &= ~MS_RDONLY; 57 return 1; 58 } 59 60 __setup("ro", readonly); 61 __setup("rw", readwrite); 62 63 static int __init root_dev_setup(char *line) 64 { 65 strscpy(saved_root_name, line, sizeof(saved_root_name)); 66 return 1; 67 } 68 69 __setup("root=", root_dev_setup); 70 71 static int __init rootwait_setup(char *str) 72 { 73 if (*str) 74 return 0; 75 root_wait = -1; 76 return 1; 77 } 78 79 __setup("rootwait", rootwait_setup); 80 81 static int __init rootwait_timeout_setup(char *str) 82 { 83 int sec; 84 85 if (kstrtoint(str, 0, &sec) || sec < 0) { 86 pr_warn("ignoring invalid rootwait value\n"); 87 goto ignore; 88 } 89 90 if (check_mul_overflow(sec, MSEC_PER_SEC, &root_wait)) { 91 pr_warn("ignoring excessive rootwait value\n"); 92 goto ignore; 93 } 94 95 return 1; 96 97 ignore: 98 /* Fallback to indefinite wait */ 99 root_wait = -1; 100 101 return 1; 102 } 103 104 __setup("rootwait=", rootwait_timeout_setup); 105 106 static char * __initdata root_mount_data; 107 static int __init root_data_setup(char *str) 108 { 109 root_mount_data = str; 110 return 1; 111 } 112 113 static char * __initdata root_fs_names; 114 static int __init fs_names_setup(char *str) 115 { 116 root_fs_names = str; 117 return 1; 118 } 119 120 static unsigned int __initdata root_delay; 121 static int __init root_delay_setup(char *str) 122 { 123 root_delay = simple_strtoul(str, NULL, 0); 124 return 1; 125 } 126 127 __setup("rootflags=", root_data_setup); 128 __setup("rootfstype=", fs_names_setup); 129 __setup("rootdelay=", root_delay_setup); 130 131 /* This can return zero length strings. Caller should check */ 132 static int __init split_fs_names(char *page, size_t size) 133 { 134 int count = 1; 135 char *p = page; 136 137 strscpy(p, root_fs_names, size); 138 while (*p++) { 139 if (p[-1] == ',') { 140 p[-1] = '\0'; 141 count++; 142 } 143 } 144 145 return count; 146 } 147 148 static int __init do_mount_root(const char *name, const char *fs, 149 const int flags, const void *data) 150 { 151 struct super_block *s; 152 struct page *p = NULL; 153 char *data_page = NULL; 154 int ret; 155 156 if (data) { 157 /* init_mount() requires a full page as fifth argument */ 158 p = alloc_page(GFP_KERNEL); 159 if (!p) 160 return -ENOMEM; 161 data_page = page_address(p); 162 /* zero-pad. init_mount() will make sure it's terminated */ 163 strncpy(data_page, data, PAGE_SIZE); 164 } 165 166 ret = init_mount(name, "/root", fs, flags, data_page); 167 if (ret) 168 goto out; 169 170 init_chdir("/root"); 171 s = current->fs->pwd.dentry->d_sb; 172 ROOT_DEV = s->s_dev; 173 printk(KERN_INFO 174 "VFS: Mounted root (%s filesystem)%s on device %u:%u.\n", 175 s->s_type->name, 176 sb_rdonly(s) ? " readonly" : "", 177 MAJOR(ROOT_DEV), MINOR(ROOT_DEV)); 178 179 out: 180 if (p) 181 put_page(p); 182 return ret; 183 } 184 185 void __init mount_root_generic(char *name, char *pretty_name, int flags) 186 { 187 struct page *page = alloc_page(GFP_KERNEL); 188 char *fs_names = page_address(page); 189 char *p; 190 char b[BDEVNAME_SIZE]; 191 int num_fs, i; 192 193 scnprintf(b, BDEVNAME_SIZE, "unknown-block(%u,%u)", 194 MAJOR(ROOT_DEV), MINOR(ROOT_DEV)); 195 if (root_fs_names) 196 num_fs = split_fs_names(fs_names, PAGE_SIZE); 197 else 198 num_fs = list_bdev_fs_names(fs_names, PAGE_SIZE); 199 retry: 200 for (i = 0, p = fs_names; i < num_fs; i++, p += strlen(p)+1) { 201 int err; 202 203 if (!*p) 204 continue; 205 err = do_mount_root(name, p, flags, root_mount_data); 206 switch (err) { 207 case 0: 208 goto out; 209 case -EACCES: 210 case -EINVAL: 211 #ifdef CONFIG_BLOCK 212 init_flush_fput(); 213 #endif 214 continue; 215 } 216 /* 217 * Allow the user to distinguish between failed sys_open 218 * and bad superblock on root device. 219 * and give them a list of the available devices 220 */ 221 printk("VFS: Cannot open root device \"%s\" or %s: error %d\n", 222 pretty_name, b, err); 223 printk("Please append a correct \"root=\" boot option; here are the available partitions:\n"); 224 printk_all_partitions(); 225 226 if (root_fs_names) 227 num_fs = list_bdev_fs_names(fs_names, PAGE_SIZE); 228 if (!num_fs) 229 pr_err("Can't find any bdev filesystem to be used for mount!\n"); 230 else { 231 pr_err("List of all bdev filesystems:\n"); 232 for (i = 0, p = fs_names; i < num_fs; i++, p += strlen(p)+1) 233 pr_err(" %s", p); 234 pr_err("\n"); 235 } 236 237 panic("VFS: Unable to mount root fs on %s", b); 238 } 239 if (!(flags & SB_RDONLY)) { 240 flags |= SB_RDONLY; 241 goto retry; 242 } 243 244 printk("List of all partitions:\n"); 245 printk_all_partitions(); 246 printk("No filesystem could mount root, tried: "); 247 for (i = 0, p = fs_names; i < num_fs; i++, p += strlen(p)+1) 248 printk(" %s", p); 249 printk("\n"); 250 panic("VFS: Unable to mount root fs on \"%s\" or %s", pretty_name, b); 251 out: 252 put_page(page); 253 } 254 255 #ifdef CONFIG_ROOT_NFS 256 257 #define NFSROOT_TIMEOUT_MIN 5 258 #define NFSROOT_TIMEOUT_MAX 30 259 #define NFSROOT_RETRY_MAX 5 260 261 static void __init mount_nfs_root(void) 262 { 263 char *root_dev, *root_data; 264 unsigned int timeout; 265 int try; 266 267 if (nfs_root_data(&root_dev, &root_data)) 268 goto fail; 269 270 /* 271 * The server or network may not be ready, so try several 272 * times. Stop after a few tries in case the client wants 273 * to fall back to other boot methods. 274 */ 275 timeout = NFSROOT_TIMEOUT_MIN; 276 for (try = 1; ; try++) { 277 if (!do_mount_root(root_dev, "nfs", root_mountflags, root_data)) 278 return; 279 if (try > NFSROOT_RETRY_MAX) 280 break; 281 282 /* Wait, in case the server refused us immediately */ 283 ssleep(timeout); 284 timeout <<= 1; 285 if (timeout > NFSROOT_TIMEOUT_MAX) 286 timeout = NFSROOT_TIMEOUT_MAX; 287 } 288 fail: 289 pr_err("VFS: Unable to mount root fs via NFS.\n"); 290 } 291 #else 292 static inline void mount_nfs_root(void) 293 { 294 } 295 #endif /* CONFIG_ROOT_NFS */ 296 297 #ifdef CONFIG_CIFS_ROOT 298 299 #define CIFSROOT_TIMEOUT_MIN 5 300 #define CIFSROOT_TIMEOUT_MAX 30 301 #define CIFSROOT_RETRY_MAX 5 302 303 static void __init mount_cifs_root(void) 304 { 305 char *root_dev, *root_data; 306 unsigned int timeout; 307 int try; 308 309 if (cifs_root_data(&root_dev, &root_data)) 310 goto fail; 311 312 timeout = CIFSROOT_TIMEOUT_MIN; 313 for (try = 1; ; try++) { 314 if (!do_mount_root(root_dev, "cifs", root_mountflags, 315 root_data)) 316 return; 317 if (try > CIFSROOT_RETRY_MAX) 318 break; 319 320 ssleep(timeout); 321 timeout <<= 1; 322 if (timeout > CIFSROOT_TIMEOUT_MAX) 323 timeout = CIFSROOT_TIMEOUT_MAX; 324 } 325 fail: 326 pr_err("VFS: Unable to mount root fs via SMB.\n"); 327 } 328 #else 329 static inline void mount_cifs_root(void) 330 { 331 } 332 #endif /* CONFIG_CIFS_ROOT */ 333 334 static bool __init fs_is_nodev(char *fstype) 335 { 336 struct file_system_type *fs = get_fs_type(fstype); 337 bool ret = false; 338 339 if (fs) { 340 ret = !(fs->fs_flags & FS_REQUIRES_DEV); 341 put_filesystem(fs); 342 } 343 344 return ret; 345 } 346 347 static int __init mount_nodev_root(char *root_device_name) 348 { 349 char *fs_names, *fstype; 350 int err = -EINVAL; 351 int num_fs, i; 352 353 fs_names = (void *)__get_free_page(GFP_KERNEL); 354 if (!fs_names) 355 return -EINVAL; 356 num_fs = split_fs_names(fs_names, PAGE_SIZE); 357 358 for (i = 0, fstype = fs_names; i < num_fs; 359 i++, fstype += strlen(fstype) + 1) { 360 if (!*fstype) 361 continue; 362 if (!fs_is_nodev(fstype)) 363 continue; 364 err = do_mount_root(root_device_name, fstype, root_mountflags, 365 root_mount_data); 366 if (!err) 367 break; 368 } 369 370 free_page((unsigned long)fs_names); 371 return err; 372 } 373 374 #ifdef CONFIG_BLOCK 375 static void __init mount_block_root(char *root_device_name) 376 { 377 int err = create_dev("/dev/root", ROOT_DEV); 378 379 if (err < 0) 380 pr_emerg("Failed to create /dev/root: %d\n", err); 381 mount_root_generic("/dev/root", root_device_name, root_mountflags); 382 } 383 #else 384 static inline void mount_block_root(char *root_device_name) 385 { 386 } 387 #endif /* CONFIG_BLOCK */ 388 389 void __init mount_root(char *root_device_name) 390 { 391 switch (ROOT_DEV) { 392 case Root_NFS: 393 mount_nfs_root(); 394 break; 395 case Root_CIFS: 396 mount_cifs_root(); 397 break; 398 case Root_Generic: 399 mount_root_generic(root_device_name, root_device_name, 400 root_mountflags); 401 break; 402 case 0: 403 if (root_device_name && root_fs_names && 404 mount_nodev_root(root_device_name) == 0) 405 break; 406 fallthrough; 407 default: 408 mount_block_root(root_device_name); 409 break; 410 } 411 } 412 413 /* wait for any asynchronous scanning to complete */ 414 static void __init wait_for_root(char *root_device_name) 415 { 416 ktime_t end; 417 418 if (ROOT_DEV != 0) 419 return; 420 421 pr_info("Waiting for root device %s...\n", root_device_name); 422 423 end = ktime_add_ms(ktime_get_raw(), root_wait); 424 425 while (!driver_probe_done() || 426 early_lookup_bdev(root_device_name, &ROOT_DEV) < 0) { 427 msleep(5); 428 if (root_wait > 0 && ktime_after(ktime_get_raw(), end)) 429 break; 430 } 431 432 async_synchronize_full(); 433 434 } 435 436 static dev_t __init parse_root_device(char *root_device_name) 437 { 438 int error; 439 dev_t dev; 440 441 if (!strncmp(root_device_name, "mtd", 3) || 442 !strncmp(root_device_name, "ubi", 3)) 443 return Root_Generic; 444 if (strcmp(root_device_name, "/dev/nfs") == 0) 445 return Root_NFS; 446 if (strcmp(root_device_name, "/dev/cifs") == 0) 447 return Root_CIFS; 448 if (strcmp(root_device_name, "/dev/ram") == 0) 449 return Root_RAM0; 450 451 error = early_lookup_bdev(root_device_name, &dev); 452 if (error) { 453 if (error == -EINVAL && root_wait) { 454 pr_err("Disabling rootwait; root= is invalid.\n"); 455 root_wait = 0; 456 } 457 return 0; 458 } 459 return dev; 460 } 461 462 /* 463 * Prepare the namespace - decide what/where to mount, load ramdisks, etc. 464 */ 465 void __init prepare_namespace(void) 466 { 467 if (root_delay) { 468 printk(KERN_INFO "Waiting %d sec before mounting root device...\n", 469 root_delay); 470 ssleep(root_delay); 471 } 472 473 /* 474 * wait for the known devices to complete their probing 475 * 476 * Note: this is a potential source of long boot delays. 477 * For example, it is not atypical to wait 5 seconds here 478 * for the touchpad of a laptop to initialize. 479 */ 480 wait_for_device_probe(); 481 482 md_run_setup(); 483 484 if (saved_root_name[0]) 485 ROOT_DEV = parse_root_device(saved_root_name); 486 487 if (initrd_load(saved_root_name)) 488 goto out; 489 490 if (root_wait) 491 wait_for_root(saved_root_name); 492 mount_root(saved_root_name); 493 out: 494 devtmpfs_mount(); 495 init_mount(".", "/", NULL, MS_MOVE, NULL); 496 init_chroot("."); 497 } 498 499 static bool is_tmpfs; 500 static int rootfs_init_fs_context(struct fs_context *fc) 501 { 502 if (IS_ENABLED(CONFIG_TMPFS) && is_tmpfs) 503 return shmem_init_fs_context(fc); 504 505 return ramfs_init_fs_context(fc); 506 } 507 508 struct file_system_type rootfs_fs_type = { 509 .name = "rootfs", 510 .init_fs_context = rootfs_init_fs_context, 511 .kill_sb = kill_litter_super, 512 }; 513 514 void __init init_rootfs(void) 515 { 516 if (IS_ENABLED(CONFIG_TMPFS)) { 517 if (!saved_root_name[0] && !root_fs_names) 518 is_tmpfs = true; 519 else if (root_fs_names && !!strstr(root_fs_names, "tmpfs")) 520 is_tmpfs = true; 521 } 522 } 523