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 strscpy_pad(data_page, data, PAGE_SIZE); 163 } 164 165 ret = init_mount(name, "/root", fs, flags, data_page); 166 if (ret) 167 goto out; 168 169 init_chdir("/root"); 170 s = current->fs->pwd.dentry->d_sb; 171 ROOT_DEV = s->s_dev; 172 printk(KERN_INFO 173 "VFS: Mounted root (%s filesystem)%s on device %u:%u.\n", 174 s->s_type->name, 175 sb_rdonly(s) ? " readonly" : "", 176 MAJOR(ROOT_DEV), MINOR(ROOT_DEV)); 177 178 out: 179 if (p) 180 put_page(p); 181 return ret; 182 } 183 184 void __init mount_root_generic(char *name, char *pretty_name, int flags) 185 { 186 struct page *page = alloc_page(GFP_KERNEL); 187 char *fs_names = page_address(page); 188 char *p; 189 char b[BDEVNAME_SIZE]; 190 int num_fs, i; 191 192 scnprintf(b, BDEVNAME_SIZE, "unknown-block(%u,%u)", 193 MAJOR(ROOT_DEV), MINOR(ROOT_DEV)); 194 if (root_fs_names) 195 num_fs = split_fs_names(fs_names, PAGE_SIZE); 196 else 197 num_fs = list_bdev_fs_names(fs_names, PAGE_SIZE); 198 retry: 199 for (i = 0, p = fs_names; i < num_fs; i++, p += strlen(p)+1) { 200 int err; 201 202 if (!*p) 203 continue; 204 err = do_mount_root(name, p, flags, root_mount_data); 205 switch (err) { 206 case 0: 207 goto out; 208 case -EACCES: 209 case -EINVAL: 210 #ifdef CONFIG_BLOCK 211 init_flush_fput(); 212 #endif 213 continue; 214 } 215 /* 216 * Allow the user to distinguish between failed sys_open 217 * and bad superblock on root device. 218 * and give them a list of the available devices 219 */ 220 printk("VFS: Cannot open root device \"%s\" or %s: error %d\n", 221 pretty_name, b, err); 222 printk("Please append a correct \"root=\" boot option; here are the available partitions:\n"); 223 printk_all_partitions(); 224 225 if (root_fs_names) 226 num_fs = list_bdev_fs_names(fs_names, PAGE_SIZE); 227 if (!num_fs) 228 pr_err("Can't find any bdev filesystem to be used for mount!\n"); 229 else { 230 pr_err("List of all bdev filesystems:\n"); 231 for (i = 0, p = fs_names; i < num_fs; i++, p += strlen(p)+1) 232 pr_err(" %s", p); 233 pr_err("\n"); 234 } 235 236 panic("VFS: Unable to mount root fs on %s", b); 237 } 238 if (!(flags & SB_RDONLY)) { 239 flags |= SB_RDONLY; 240 goto retry; 241 } 242 243 printk("List of all partitions:\n"); 244 printk_all_partitions(); 245 printk("No filesystem could mount root, tried: "); 246 for (i = 0, p = fs_names; i < num_fs; i++, p += strlen(p)+1) 247 printk(" %s", p); 248 printk("\n"); 249 panic("VFS: Unable to mount root fs on \"%s\" or %s", pretty_name, b); 250 out: 251 put_page(page); 252 } 253 254 #ifdef CONFIG_ROOT_NFS 255 256 #define NFSROOT_TIMEOUT_MIN 5 257 #define NFSROOT_TIMEOUT_MAX 30 258 #define NFSROOT_RETRY_MAX 5 259 260 static void __init mount_nfs_root(void) 261 { 262 char *root_dev, *root_data; 263 unsigned int timeout; 264 int try; 265 266 if (nfs_root_data(&root_dev, &root_data)) 267 goto fail; 268 269 /* 270 * The server or network may not be ready, so try several 271 * times. Stop after a few tries in case the client wants 272 * to fall back to other boot methods. 273 */ 274 timeout = NFSROOT_TIMEOUT_MIN; 275 for (try = 1; ; try++) { 276 if (!do_mount_root(root_dev, "nfs", root_mountflags, root_data)) 277 return; 278 if (try > NFSROOT_RETRY_MAX) 279 break; 280 281 /* Wait, in case the server refused us immediately */ 282 ssleep(timeout); 283 timeout <<= 1; 284 if (timeout > NFSROOT_TIMEOUT_MAX) 285 timeout = NFSROOT_TIMEOUT_MAX; 286 } 287 fail: 288 pr_err("VFS: Unable to mount root fs via NFS.\n"); 289 } 290 #else 291 static inline void mount_nfs_root(void) 292 { 293 } 294 #endif /* CONFIG_ROOT_NFS */ 295 296 #ifdef CONFIG_CIFS_ROOT 297 298 #define CIFSROOT_TIMEOUT_MIN 5 299 #define CIFSROOT_TIMEOUT_MAX 30 300 #define CIFSROOT_RETRY_MAX 5 301 302 static void __init mount_cifs_root(void) 303 { 304 char *root_dev, *root_data; 305 unsigned int timeout; 306 int try; 307 308 if (cifs_root_data(&root_dev, &root_data)) 309 goto fail; 310 311 timeout = CIFSROOT_TIMEOUT_MIN; 312 for (try = 1; ; try++) { 313 if (!do_mount_root(root_dev, "cifs", root_mountflags, 314 root_data)) 315 return; 316 if (try > CIFSROOT_RETRY_MAX) 317 break; 318 319 ssleep(timeout); 320 timeout <<= 1; 321 if (timeout > CIFSROOT_TIMEOUT_MAX) 322 timeout = CIFSROOT_TIMEOUT_MAX; 323 } 324 fail: 325 pr_err("VFS: Unable to mount root fs via SMB.\n"); 326 } 327 #else 328 static inline void mount_cifs_root(void) 329 { 330 } 331 #endif /* CONFIG_CIFS_ROOT */ 332 333 static bool __init fs_is_nodev(char *fstype) 334 { 335 struct file_system_type *fs = get_fs_type(fstype); 336 bool ret = false; 337 338 if (fs) { 339 ret = !(fs->fs_flags & FS_REQUIRES_DEV); 340 put_filesystem(fs); 341 } 342 343 return ret; 344 } 345 346 static int __init mount_nodev_root(char *root_device_name) 347 { 348 char *fs_names, *fstype; 349 int err = -EINVAL; 350 int num_fs, i; 351 352 fs_names = (void *)__get_free_page(GFP_KERNEL); 353 if (!fs_names) 354 return -EINVAL; 355 num_fs = split_fs_names(fs_names, PAGE_SIZE); 356 357 for (i = 0, fstype = fs_names; i < num_fs; 358 i++, fstype += strlen(fstype) + 1) { 359 if (!*fstype) 360 continue; 361 if (!fs_is_nodev(fstype)) 362 continue; 363 err = do_mount_root(root_device_name, fstype, root_mountflags, 364 root_mount_data); 365 if (!err) 366 break; 367 } 368 369 free_page((unsigned long)fs_names); 370 return err; 371 } 372 373 #ifdef CONFIG_BLOCK 374 static void __init mount_block_root(char *root_device_name) 375 { 376 int err = create_dev("/dev/root", ROOT_DEV); 377 378 if (err < 0) 379 pr_emerg("Failed to create /dev/root: %d\n", err); 380 mount_root_generic("/dev/root", root_device_name, root_mountflags); 381 } 382 #else 383 static inline void mount_block_root(char *root_device_name) 384 { 385 } 386 #endif /* CONFIG_BLOCK */ 387 388 void __init mount_root(char *root_device_name) 389 { 390 switch (ROOT_DEV) { 391 case Root_NFS: 392 mount_nfs_root(); 393 break; 394 case Root_CIFS: 395 mount_cifs_root(); 396 break; 397 case Root_Generic: 398 mount_root_generic(root_device_name, root_device_name, 399 root_mountflags); 400 break; 401 case 0: 402 if (root_device_name && root_fs_names && 403 mount_nodev_root(root_device_name) == 0) 404 break; 405 fallthrough; 406 default: 407 mount_block_root(root_device_name); 408 break; 409 } 410 } 411 412 /* wait for any asynchronous scanning to complete */ 413 static void __init wait_for_root(char *root_device_name) 414 { 415 ktime_t end; 416 417 if (ROOT_DEV != 0) 418 return; 419 420 pr_info("Waiting for root device %s...\n", root_device_name); 421 422 end = ktime_add_ms(ktime_get_raw(), root_wait); 423 424 while (!driver_probe_done() || 425 early_lookup_bdev(root_device_name, &ROOT_DEV) < 0) { 426 msleep(5); 427 if (root_wait > 0 && ktime_after(ktime_get_raw(), end)) 428 break; 429 } 430 431 async_synchronize_full(); 432 433 } 434 435 static dev_t __init parse_root_device(char *root_device_name) 436 { 437 int error; 438 dev_t dev; 439 440 if (!strncmp(root_device_name, "mtd", 3) || 441 !strncmp(root_device_name, "ubi", 3)) 442 return Root_Generic; 443 if (strcmp(root_device_name, "/dev/nfs") == 0) 444 return Root_NFS; 445 if (strcmp(root_device_name, "/dev/cifs") == 0) 446 return Root_CIFS; 447 if (strcmp(root_device_name, "/dev/ram") == 0) 448 return Root_RAM0; 449 450 error = early_lookup_bdev(root_device_name, &dev); 451 if (error) { 452 if (error == -EINVAL && root_wait) { 453 pr_err("Disabling rootwait; root= is invalid.\n"); 454 root_wait = 0; 455 } 456 return 0; 457 } 458 return dev; 459 } 460 461 /* 462 * Prepare the namespace - decide what/where to mount, load ramdisks, etc. 463 */ 464 void __init prepare_namespace(void) 465 { 466 if (root_delay) { 467 printk(KERN_INFO "Waiting %d sec before mounting root device...\n", 468 root_delay); 469 ssleep(root_delay); 470 } 471 472 /* 473 * wait for the known devices to complete their probing 474 * 475 * Note: this is a potential source of long boot delays. 476 * For example, it is not atypical to wait 5 seconds here 477 * for the touchpad of a laptop to initialize. 478 */ 479 wait_for_device_probe(); 480 481 md_run_setup(); 482 483 if (saved_root_name[0]) 484 ROOT_DEV = parse_root_device(saved_root_name); 485 486 if (initrd_load(saved_root_name)) 487 goto out; 488 489 if (root_wait) 490 wait_for_root(saved_root_name); 491 mount_root(saved_root_name); 492 out: 493 devtmpfs_mount(); 494 init_mount(".", "/", NULL, MS_MOVE, NULL); 495 init_chroot("."); 496 } 497 498 static bool is_tmpfs; 499 static int rootfs_init_fs_context(struct fs_context *fc) 500 { 501 if (IS_ENABLED(CONFIG_TMPFS) && is_tmpfs) 502 return shmem_init_fs_context(fc); 503 504 return ramfs_init_fs_context(fc); 505 } 506 507 struct file_system_type rootfs_fs_type = { 508 .name = "rootfs", 509 .init_fs_context = rootfs_init_fs_context, 510 .kill_sb = kill_litter_super, 511 }; 512 513 void __init init_rootfs(void) 514 { 515 if (IS_ENABLED(CONFIG_TMPFS)) { 516 if (!saved_root_name[0] && !root_fs_names) 517 is_tmpfs = true; 518 else if (root_fs_names && !!strstr(root_fs_names, "tmpfs")) 519 is_tmpfs = true; 520 } 521 } 522