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 continue; 212 } 213 /* 214 * Allow the user to distinguish between failed sys_open 215 * and bad superblock on root device. 216 * and give them a list of the available devices 217 */ 218 printk("VFS: Cannot open root device \"%s\" or %s: error %d\n", 219 pretty_name, b, err); 220 printk("Please append a correct \"root=\" boot option; here are the available partitions:\n"); 221 printk_all_partitions(); 222 223 if (root_fs_names) 224 num_fs = list_bdev_fs_names(fs_names, PAGE_SIZE); 225 if (!num_fs) 226 pr_err("Can't find any bdev filesystem to be used for mount!\n"); 227 else { 228 pr_err("List of all bdev filesystems:\n"); 229 for (i = 0, p = fs_names; i < num_fs; i++, p += strlen(p)+1) 230 pr_err(" %s", p); 231 pr_err("\n"); 232 } 233 234 panic("VFS: Unable to mount root fs on %s", b); 235 } 236 if (!(flags & SB_RDONLY)) { 237 flags |= SB_RDONLY; 238 goto retry; 239 } 240 241 printk("List of all partitions:\n"); 242 printk_all_partitions(); 243 printk("No filesystem could mount root, tried: "); 244 for (i = 0, p = fs_names; i < num_fs; i++, p += strlen(p)+1) 245 printk(" %s", p); 246 printk("\n"); 247 panic("VFS: Unable to mount root fs on %s", b); 248 out: 249 put_page(page); 250 } 251 252 #ifdef CONFIG_ROOT_NFS 253 254 #define NFSROOT_TIMEOUT_MIN 5 255 #define NFSROOT_TIMEOUT_MAX 30 256 #define NFSROOT_RETRY_MAX 5 257 258 static void __init mount_nfs_root(void) 259 { 260 char *root_dev, *root_data; 261 unsigned int timeout; 262 int try; 263 264 if (nfs_root_data(&root_dev, &root_data)) 265 goto fail; 266 267 /* 268 * The server or network may not be ready, so try several 269 * times. Stop after a few tries in case the client wants 270 * to fall back to other boot methods. 271 */ 272 timeout = NFSROOT_TIMEOUT_MIN; 273 for (try = 1; ; try++) { 274 if (!do_mount_root(root_dev, "nfs", root_mountflags, root_data)) 275 return; 276 if (try > NFSROOT_RETRY_MAX) 277 break; 278 279 /* Wait, in case the server refused us immediately */ 280 ssleep(timeout); 281 timeout <<= 1; 282 if (timeout > NFSROOT_TIMEOUT_MAX) 283 timeout = NFSROOT_TIMEOUT_MAX; 284 } 285 fail: 286 pr_err("VFS: Unable to mount root fs via NFS.\n"); 287 } 288 #else 289 static inline void mount_nfs_root(void) 290 { 291 } 292 #endif /* CONFIG_ROOT_NFS */ 293 294 #ifdef CONFIG_CIFS_ROOT 295 296 #define CIFSROOT_TIMEOUT_MIN 5 297 #define CIFSROOT_TIMEOUT_MAX 30 298 #define CIFSROOT_RETRY_MAX 5 299 300 static void __init mount_cifs_root(void) 301 { 302 char *root_dev, *root_data; 303 unsigned int timeout; 304 int try; 305 306 if (cifs_root_data(&root_dev, &root_data)) 307 goto fail; 308 309 timeout = CIFSROOT_TIMEOUT_MIN; 310 for (try = 1; ; try++) { 311 if (!do_mount_root(root_dev, "cifs", root_mountflags, 312 root_data)) 313 return; 314 if (try > CIFSROOT_RETRY_MAX) 315 break; 316 317 ssleep(timeout); 318 timeout <<= 1; 319 if (timeout > CIFSROOT_TIMEOUT_MAX) 320 timeout = CIFSROOT_TIMEOUT_MAX; 321 } 322 fail: 323 pr_err("VFS: Unable to mount root fs via SMB.\n"); 324 } 325 #else 326 static inline void mount_cifs_root(void) 327 { 328 } 329 #endif /* CONFIG_CIFS_ROOT */ 330 331 static bool __init fs_is_nodev(char *fstype) 332 { 333 struct file_system_type *fs = get_fs_type(fstype); 334 bool ret = false; 335 336 if (fs) { 337 ret = !(fs->fs_flags & FS_REQUIRES_DEV); 338 put_filesystem(fs); 339 } 340 341 return ret; 342 } 343 344 static int __init mount_nodev_root(char *root_device_name) 345 { 346 char *fs_names, *fstype; 347 int err = -EINVAL; 348 int num_fs, i; 349 350 fs_names = (void *)__get_free_page(GFP_KERNEL); 351 if (!fs_names) 352 return -EINVAL; 353 num_fs = split_fs_names(fs_names, PAGE_SIZE); 354 355 for (i = 0, fstype = fs_names; i < num_fs; 356 i++, fstype += strlen(fstype) + 1) { 357 if (!*fstype) 358 continue; 359 if (!fs_is_nodev(fstype)) 360 continue; 361 err = do_mount_root(root_device_name, fstype, root_mountflags, 362 root_mount_data); 363 if (!err) 364 break; 365 } 366 367 free_page((unsigned long)fs_names); 368 return err; 369 } 370 371 #ifdef CONFIG_BLOCK 372 static void __init mount_block_root(char *root_device_name) 373 { 374 int err = create_dev("/dev/root", ROOT_DEV); 375 376 if (err < 0) 377 pr_emerg("Failed to create /dev/root: %d\n", err); 378 mount_root_generic("/dev/root", root_device_name, root_mountflags); 379 } 380 #else 381 static inline void mount_block_root(char *root_device_name) 382 { 383 } 384 #endif /* CONFIG_BLOCK */ 385 386 void __init mount_root(char *root_device_name) 387 { 388 switch (ROOT_DEV) { 389 case Root_NFS: 390 mount_nfs_root(); 391 break; 392 case Root_CIFS: 393 mount_cifs_root(); 394 break; 395 case Root_Generic: 396 mount_root_generic(root_device_name, root_device_name, 397 root_mountflags); 398 break; 399 case 0: 400 if (root_device_name && root_fs_names && 401 mount_nodev_root(root_device_name) == 0) 402 break; 403 fallthrough; 404 default: 405 mount_block_root(root_device_name); 406 break; 407 } 408 } 409 410 /* wait for any asynchronous scanning to complete */ 411 static void __init wait_for_root(char *root_device_name) 412 { 413 ktime_t end; 414 415 if (ROOT_DEV != 0) 416 return; 417 418 pr_info("Waiting for root device %s...\n", root_device_name); 419 420 end = ktime_add_ms(ktime_get_raw(), root_wait); 421 422 while (!driver_probe_done() || 423 early_lookup_bdev(root_device_name, &ROOT_DEV) < 0) { 424 msleep(5); 425 if (root_wait > 0 && ktime_after(ktime_get_raw(), end)) 426 break; 427 } 428 429 async_synchronize_full(); 430 431 } 432 433 static dev_t __init parse_root_device(char *root_device_name) 434 { 435 int error; 436 dev_t dev; 437 438 if (!strncmp(root_device_name, "mtd", 3) || 439 !strncmp(root_device_name, "ubi", 3)) 440 return Root_Generic; 441 if (strcmp(root_device_name, "/dev/nfs") == 0) 442 return Root_NFS; 443 if (strcmp(root_device_name, "/dev/cifs") == 0) 444 return Root_CIFS; 445 if (strcmp(root_device_name, "/dev/ram") == 0) 446 return Root_RAM0; 447 448 error = early_lookup_bdev(root_device_name, &dev); 449 if (error) { 450 if (error == -EINVAL && root_wait) { 451 pr_err("Disabling rootwait; root= is invalid.\n"); 452 root_wait = 0; 453 } 454 return 0; 455 } 456 return dev; 457 } 458 459 /* 460 * Prepare the namespace - decide what/where to mount, load ramdisks, etc. 461 */ 462 void __init prepare_namespace(void) 463 { 464 if (root_delay) { 465 printk(KERN_INFO "Waiting %d sec before mounting root device...\n", 466 root_delay); 467 ssleep(root_delay); 468 } 469 470 /* 471 * wait for the known devices to complete their probing 472 * 473 * Note: this is a potential source of long boot delays. 474 * For example, it is not atypical to wait 5 seconds here 475 * for the touchpad of a laptop to initialize. 476 */ 477 wait_for_device_probe(); 478 479 md_run_setup(); 480 481 if (saved_root_name[0]) 482 ROOT_DEV = parse_root_device(saved_root_name); 483 484 if (initrd_load(saved_root_name)) 485 goto out; 486 487 if (root_wait) 488 wait_for_root(saved_root_name); 489 mount_root(saved_root_name); 490 out: 491 devtmpfs_mount(); 492 init_mount(".", "/", NULL, MS_MOVE, NULL); 493 init_chroot("."); 494 } 495 496 static bool is_tmpfs; 497 static int rootfs_init_fs_context(struct fs_context *fc) 498 { 499 if (IS_ENABLED(CONFIG_TMPFS) && is_tmpfs) 500 return shmem_init_fs_context(fc); 501 502 return ramfs_init_fs_context(fc); 503 } 504 505 struct file_system_type rootfs_fs_type = { 506 .name = "rootfs", 507 .init_fs_context = rootfs_init_fs_context, 508 .kill_sb = kill_litter_super, 509 }; 510 511 void __init init_rootfs(void) 512 { 513 if (IS_ENABLED(CONFIG_TMPFS)) { 514 if (!saved_root_name[0] && !root_fs_names) 515 is_tmpfs = true; 516 else if (root_fs_names && !!strstr(root_fs_names, "tmpfs")) 517 is_tmpfs = true; 518 } 519 } 520