Line data Source code
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 :
22 : #include <linux/nfs_fs.h>
23 : #include <linux/nfs_fs_sb.h>
24 : #include <linux/nfs_mount.h>
25 : #include <linux/raid/detect.h>
26 : #include <uapi/linux/mount.h>
27 :
28 : #include "do_mounts.h"
29 :
30 : int root_mountflags = MS_RDONLY | MS_SILENT;
31 : static char * __initdata root_device_name;
32 : static char __initdata saved_root_name[64];
33 : static int root_wait;
34 :
35 : dev_t ROOT_DEV;
36 :
37 0 : static int __init load_ramdisk(char *str)
38 : {
39 0 : pr_warn("ignoring the deprecated load_ramdisk= option\n");
40 0 : return 1;
41 : }
42 : __setup("load_ramdisk=", load_ramdisk);
43 :
44 0 : static int __init readonly(char *str)
45 : {
46 0 : if (*str)
47 : return 0;
48 0 : root_mountflags |= MS_RDONLY;
49 0 : return 1;
50 : }
51 :
52 0 : static int __init readwrite(char *str)
53 : {
54 0 : if (*str)
55 : return 0;
56 0 : root_mountflags &= ~MS_RDONLY;
57 0 : return 1;
58 : }
59 :
60 : __setup("ro", readonly);
61 : __setup("rw", readwrite);
62 :
63 : #ifdef CONFIG_BLOCK
64 : struct uuidcmp {
65 : const char *uuid;
66 : int len;
67 : };
68 :
69 : /**
70 : * match_dev_by_uuid - callback for finding a partition using its uuid
71 : * @dev: device passed in by the caller
72 : * @data: opaque pointer to the desired struct uuidcmp to match
73 : *
74 : * Returns 1 if the device matches, and 0 otherwise.
75 : */
76 0 : static int match_dev_by_uuid(struct device *dev, const void *data)
77 : {
78 0 : struct block_device *bdev = dev_to_bdev(dev);
79 0 : const struct uuidcmp *cmp = data;
80 :
81 0 : if (!bdev->bd_meta_info ||
82 0 : strncasecmp(cmp->uuid, bdev->bd_meta_info->uuid, cmp->len))
83 : return 0;
84 : return 1;
85 : }
86 :
87 : /**
88 : * devt_from_partuuid - looks up the dev_t of a partition by its UUID
89 : * @uuid_str: char array containing ascii UUID
90 : *
91 : * The function will return the first partition which contains a matching
92 : * UUID value in its partition_meta_info struct. This does not search
93 : * by filesystem UUIDs.
94 : *
95 : * If @uuid_str is followed by a "/PARTNROFF=%d", then the number will be
96 : * extracted and used as an offset from the partition identified by the UUID.
97 : *
98 : * Returns the matching dev_t on success or 0 on failure.
99 : */
100 0 : static dev_t devt_from_partuuid(const char *uuid_str)
101 : {
102 : struct uuidcmp cmp;
103 0 : struct device *dev = NULL;
104 0 : dev_t devt = 0;
105 0 : int offset = 0;
106 : char *slash;
107 :
108 0 : cmp.uuid = uuid_str;
109 :
110 0 : slash = strchr(uuid_str, '/');
111 : /* Check for optional partition number offset attributes. */
112 0 : if (slash) {
113 0 : char c = 0;
114 :
115 : /* Explicitly fail on poor PARTUUID syntax. */
116 0 : if (sscanf(slash + 1, "PARTNROFF=%d%c", &offset, &c) != 1)
117 : goto clear_root_wait;
118 0 : cmp.len = slash - uuid_str;
119 : } else {
120 0 : cmp.len = strlen(uuid_str);
121 : }
122 :
123 0 : if (!cmp.len)
124 : goto clear_root_wait;
125 :
126 0 : dev = class_find_device(&block_class, NULL, &cmp, &match_dev_by_uuid);
127 0 : if (!dev)
128 : return 0;
129 :
130 0 : if (offset) {
131 : /*
132 : * Attempt to find the requested partition by adding an offset
133 : * to the partition number found by UUID.
134 : */
135 0 : devt = part_devt(dev_to_disk(dev),
136 0 : dev_to_bdev(dev)->bd_partno + offset);
137 : } else {
138 0 : devt = dev->devt;
139 : }
140 :
141 0 : put_device(dev);
142 0 : return devt;
143 :
144 : clear_root_wait:
145 0 : pr_err("VFS: PARTUUID= is invalid.\n"
146 : "Expected PARTUUID=<valid-uuid-id>[/PARTNROFF=%%d]\n");
147 0 : if (root_wait)
148 0 : pr_err("Disabling rootwait; root= is invalid.\n");
149 0 : root_wait = 0;
150 0 : return 0;
151 : }
152 :
153 : /**
154 : * match_dev_by_label - callback for finding a partition using its label
155 : * @dev: device passed in by the caller
156 : * @data: opaque pointer to the label to match
157 : *
158 : * Returns 1 if the device matches, and 0 otherwise.
159 : */
160 0 : static int match_dev_by_label(struct device *dev, const void *data)
161 : {
162 0 : struct block_device *bdev = dev_to_bdev(dev);
163 0 : const char *label = data;
164 :
165 0 : if (!bdev->bd_meta_info || strcmp(label, bdev->bd_meta_info->volname))
166 : return 0;
167 : return 1;
168 : }
169 :
170 0 : static dev_t devt_from_partlabel(const char *label)
171 : {
172 : struct device *dev;
173 0 : dev_t devt = 0;
174 :
175 0 : dev = class_find_device(&block_class, NULL, label, &match_dev_by_label);
176 0 : if (dev) {
177 0 : devt = dev->devt;
178 0 : put_device(dev);
179 : }
180 :
181 0 : return devt;
182 : }
183 :
184 0 : static dev_t devt_from_devname(const char *name)
185 : {
186 0 : dev_t devt = 0;
187 : int part;
188 : char s[32];
189 : char *p;
190 :
191 0 : if (strlen(name) > 31)
192 : return 0;
193 0 : strcpy(s, name);
194 0 : for (p = s; *p; p++) {
195 0 : if (*p == '/')
196 0 : *p = '!';
197 : }
198 :
199 0 : devt = blk_lookup_devt(s, 0);
200 0 : if (devt)
201 : return devt;
202 :
203 : /*
204 : * Try non-existent, but valid partition, which may only exist after
205 : * opening the device, like partitioned md devices.
206 : */
207 0 : while (p > s && isdigit(p[-1]))
208 0 : p--;
209 0 : if (p == s || !*p || *p == '0')
210 : return 0;
211 :
212 : /* try disk name without <part number> */
213 0 : part = simple_strtoul(p, NULL, 10);
214 0 : *p = '\0';
215 0 : devt = blk_lookup_devt(s, part);
216 0 : if (devt)
217 : return devt;
218 :
219 : /* try disk name without p<part number> */
220 0 : if (p < s + 2 || !isdigit(p[-2]) || p[-1] != 'p')
221 : return 0;
222 0 : p[-1] = '\0';
223 0 : return blk_lookup_devt(s, part);
224 : }
225 : #endif /* CONFIG_BLOCK */
226 :
227 0 : static dev_t devt_from_devnum(const char *name)
228 : {
229 : unsigned maj, min, offset;
230 0 : dev_t devt = 0;
231 : char *p, dummy;
232 :
233 0 : if (sscanf(name, "%u:%u%c", &maj, &min, &dummy) == 2 ||
234 0 : sscanf(name, "%u:%u:%u:%c", &maj, &min, &offset, &dummy) == 3) {
235 0 : devt = MKDEV(maj, min);
236 0 : if (maj != MAJOR(devt) || min != MINOR(devt))
237 : return 0;
238 : } else {
239 0 : devt = new_decode_dev(simple_strtoul(name, &p, 16));
240 0 : if (*p)
241 : return 0;
242 : }
243 :
244 : return devt;
245 : }
246 :
247 : /*
248 : * Convert a name into device number. We accept the following variants:
249 : *
250 : * 1) <hex_major><hex_minor> device number in hexadecimal represents itself
251 : * no leading 0x, for example b302.
252 : * 2) /dev/nfs represents Root_NFS (0xff)
253 : * 3) /dev/<disk_name> represents the device number of disk
254 : * 4) /dev/<disk_name><decimal> represents the device number
255 : * of partition - device number of disk plus the partition number
256 : * 5) /dev/<disk_name>p<decimal> - same as the above, that form is
257 : * used when disk name of partitioned disk ends on a digit.
258 : * 6) PARTUUID=00112233-4455-6677-8899-AABBCCDDEEFF representing the
259 : * unique id of a partition if the partition table provides it.
260 : * The UUID may be either an EFI/GPT UUID, or refer to an MSDOS
261 : * partition using the format SSSSSSSS-PP, where SSSSSSSS is a zero-
262 : * filled hex representation of the 32-bit "NT disk signature", and PP
263 : * is a zero-filled hex representation of the 1-based partition number.
264 : * 7) PARTUUID=<UUID>/PARTNROFF=<int> to select a partition in relation to
265 : * a partition with a known unique id.
266 : * 8) <major>:<minor> major and minor number of the device separated by
267 : * a colon.
268 : * 9) PARTLABEL=<name> with name being the GPT partition label.
269 : * MSDOS partitions do not support labels!
270 : * 10) /dev/cifs represents Root_CIFS (0xfe)
271 : *
272 : * If name doesn't have fall into the categories above, we return (0,0).
273 : * block_class is used to check if something is a disk name. If the disk
274 : * name contains slashes, the device name has them replaced with
275 : * bangs.
276 : */
277 0 : dev_t name_to_dev_t(const char *name)
278 : {
279 0 : if (strcmp(name, "/dev/nfs") == 0)
280 : return Root_NFS;
281 0 : if (strcmp(name, "/dev/cifs") == 0)
282 : return Root_CIFS;
283 0 : if (strcmp(name, "/dev/ram") == 0)
284 : return Root_RAM0;
285 : #ifdef CONFIG_BLOCK
286 0 : if (strncmp(name, "PARTUUID=", 9) == 0)
287 0 : return devt_from_partuuid(name + 9);
288 0 : if (strncmp(name, "PARTLABEL=", 10) == 0)
289 0 : return devt_from_partlabel(name + 10);
290 0 : if (strncmp(name, "/dev/", 5) == 0)
291 0 : return devt_from_devname(name + 5);
292 : #endif
293 0 : return devt_from_devnum(name);
294 : }
295 : EXPORT_SYMBOL_GPL(name_to_dev_t);
296 :
297 1 : static int __init root_dev_setup(char *line)
298 : {
299 1 : strscpy(saved_root_name, line, sizeof(saved_root_name));
300 1 : return 1;
301 : }
302 :
303 : __setup("root=", root_dev_setup);
304 :
305 0 : static int __init rootwait_setup(char *str)
306 : {
307 0 : if (*str)
308 : return 0;
309 0 : root_wait = 1;
310 0 : return 1;
311 : }
312 :
313 : __setup("rootwait", rootwait_setup);
314 :
315 : static char * __initdata root_mount_data;
316 0 : static int __init root_data_setup(char *str)
317 : {
318 0 : root_mount_data = str;
319 0 : return 1;
320 : }
321 :
322 : static char * __initdata root_fs_names;
323 0 : static int __init fs_names_setup(char *str)
324 : {
325 0 : root_fs_names = str;
326 0 : return 1;
327 : }
328 :
329 : static unsigned int __initdata root_delay;
330 0 : static int __init root_delay_setup(char *str)
331 : {
332 0 : root_delay = simple_strtoul(str, NULL, 0);
333 0 : return 1;
334 : }
335 :
336 : __setup("rootflags=", root_data_setup);
337 : __setup("rootfstype=", fs_names_setup);
338 : __setup("rootdelay=", root_delay_setup);
339 :
340 : /* This can return zero length strings. Caller should check */
341 0 : static int __init split_fs_names(char *page, size_t size, char *names)
342 : {
343 0 : int count = 1;
344 0 : char *p = page;
345 :
346 0 : strscpy(p, root_fs_names, size);
347 0 : while (*p++) {
348 0 : if (p[-1] == ',') {
349 0 : p[-1] = '\0';
350 0 : count++;
351 : }
352 : }
353 :
354 0 : return count;
355 : }
356 :
357 0 : static int __init do_mount_root(const char *name, const char *fs,
358 : const int flags, const void *data)
359 : {
360 : struct super_block *s;
361 0 : struct page *p = NULL;
362 0 : char *data_page = NULL;
363 : int ret;
364 :
365 0 : if (data) {
366 : /* init_mount() requires a full page as fifth argument */
367 0 : p = alloc_page(GFP_KERNEL);
368 0 : if (!p)
369 : return -ENOMEM;
370 0 : data_page = page_address(p);
371 : /* zero-pad. init_mount() will make sure it's terminated */
372 0 : strncpy(data_page, data, PAGE_SIZE);
373 : }
374 :
375 0 : ret = init_mount(name, "/root", fs, flags, data_page);
376 0 : if (ret)
377 : goto out;
378 :
379 0 : init_chdir("/root");
380 0 : s = current->fs->pwd.dentry->d_sb;
381 0 : ROOT_DEV = s->s_dev;
382 0 : printk(KERN_INFO
383 : "VFS: Mounted root (%s filesystem)%s on device %u:%u.\n",
384 : s->s_type->name,
385 : sb_rdonly(s) ? " readonly" : "",
386 : MAJOR(ROOT_DEV), MINOR(ROOT_DEV));
387 :
388 : out:
389 0 : if (p)
390 0 : put_page(p);
391 : return ret;
392 : }
393 :
394 0 : void __init mount_block_root(char *name, int flags)
395 : {
396 0 : struct page *page = alloc_page(GFP_KERNEL);
397 0 : char *fs_names = page_address(page);
398 : char *p;
399 : char b[BDEVNAME_SIZE];
400 : int num_fs, i;
401 :
402 0 : scnprintf(b, BDEVNAME_SIZE, "unknown-block(%u,%u)",
403 0 : MAJOR(ROOT_DEV), MINOR(ROOT_DEV));
404 0 : if (root_fs_names)
405 0 : num_fs = split_fs_names(fs_names, PAGE_SIZE, root_fs_names);
406 : else
407 0 : num_fs = list_bdev_fs_names(fs_names, PAGE_SIZE);
408 : retry:
409 0 : for (i = 0, p = fs_names; i < num_fs; i++, p += strlen(p)+1) {
410 : int err;
411 :
412 0 : if (!*p)
413 0 : continue;
414 0 : err = do_mount_root(name, p, flags, root_mount_data);
415 0 : switch (err) {
416 : case 0:
417 : goto out;
418 : case -EACCES:
419 : case -EINVAL:
420 0 : continue;
421 : }
422 : /*
423 : * Allow the user to distinguish between failed sys_open
424 : * and bad superblock on root device.
425 : * and give them a list of the available devices
426 : */
427 0 : printk("VFS: Cannot open root device \"%s\" or %s: error %d\n",
428 : root_device_name, b, err);
429 0 : printk("Please append a correct \"root=\" boot option; here are the available partitions:\n");
430 :
431 0 : printk_all_partitions();
432 0 : panic("VFS: Unable to mount root fs on %s", b);
433 : }
434 0 : if (!(flags & SB_RDONLY)) {
435 0 : flags |= SB_RDONLY;
436 0 : goto retry;
437 : }
438 :
439 0 : printk("List of all partitions:\n");
440 0 : printk_all_partitions();
441 0 : printk("No filesystem could mount root, tried: ");
442 0 : for (i = 0, p = fs_names; i < num_fs; i++, p += strlen(p)+1)
443 0 : printk(" %s", p);
444 0 : printk("\n");
445 0 : panic("VFS: Unable to mount root fs on %s", b);
446 : out:
447 0 : put_page(page);
448 0 : }
449 :
450 : #ifdef CONFIG_ROOT_NFS
451 :
452 : #define NFSROOT_TIMEOUT_MIN 5
453 : #define NFSROOT_TIMEOUT_MAX 30
454 : #define NFSROOT_RETRY_MAX 5
455 :
456 : static int __init mount_nfs_root(void)
457 : {
458 : char *root_dev, *root_data;
459 : unsigned int timeout;
460 : int try, err;
461 :
462 : err = nfs_root_data(&root_dev, &root_data);
463 : if (err != 0)
464 : return 0;
465 :
466 : /*
467 : * The server or network may not be ready, so try several
468 : * times. Stop after a few tries in case the client wants
469 : * to fall back to other boot methods.
470 : */
471 : timeout = NFSROOT_TIMEOUT_MIN;
472 : for (try = 1; ; try++) {
473 : err = do_mount_root(root_dev, "nfs",
474 : root_mountflags, root_data);
475 : if (err == 0)
476 : return 1;
477 : if (try > NFSROOT_RETRY_MAX)
478 : break;
479 :
480 : /* Wait, in case the server refused us immediately */
481 : ssleep(timeout);
482 : timeout <<= 1;
483 : if (timeout > NFSROOT_TIMEOUT_MAX)
484 : timeout = NFSROOT_TIMEOUT_MAX;
485 : }
486 : return 0;
487 : }
488 : #endif
489 :
490 : #ifdef CONFIG_CIFS_ROOT
491 :
492 : extern int cifs_root_data(char **dev, char **opts);
493 :
494 : #define CIFSROOT_TIMEOUT_MIN 5
495 : #define CIFSROOT_TIMEOUT_MAX 30
496 : #define CIFSROOT_RETRY_MAX 5
497 :
498 : static int __init mount_cifs_root(void)
499 : {
500 : char *root_dev, *root_data;
501 : unsigned int timeout;
502 : int try, err;
503 :
504 : err = cifs_root_data(&root_dev, &root_data);
505 : if (err != 0)
506 : return 0;
507 :
508 : timeout = CIFSROOT_TIMEOUT_MIN;
509 : for (try = 1; ; try++) {
510 : err = do_mount_root(root_dev, "cifs", root_mountflags,
511 : root_data);
512 : if (err == 0)
513 : return 1;
514 : if (try > CIFSROOT_RETRY_MAX)
515 : break;
516 :
517 : ssleep(timeout);
518 : timeout <<= 1;
519 : if (timeout > CIFSROOT_TIMEOUT_MAX)
520 : timeout = CIFSROOT_TIMEOUT_MAX;
521 : }
522 : return 0;
523 : }
524 : #endif
525 :
526 0 : static bool __init fs_is_nodev(char *fstype)
527 : {
528 0 : struct file_system_type *fs = get_fs_type(fstype);
529 0 : bool ret = false;
530 :
531 0 : if (fs) {
532 0 : ret = !(fs->fs_flags & FS_REQUIRES_DEV);
533 0 : put_filesystem(fs);
534 : }
535 :
536 0 : return ret;
537 : }
538 :
539 0 : static int __init mount_nodev_root(void)
540 : {
541 : char *fs_names, *fstype;
542 0 : int err = -EINVAL;
543 : int num_fs, i;
544 :
545 0 : fs_names = (void *)__get_free_page(GFP_KERNEL);
546 0 : if (!fs_names)
547 : return -EINVAL;
548 0 : num_fs = split_fs_names(fs_names, PAGE_SIZE, root_fs_names);
549 :
550 0 : for (i = 0, fstype = fs_names; i < num_fs;
551 0 : i++, fstype += strlen(fstype) + 1) {
552 0 : if (!*fstype)
553 0 : continue;
554 0 : if (!fs_is_nodev(fstype))
555 0 : continue;
556 0 : err = do_mount_root(root_device_name, fstype, root_mountflags,
557 : root_mount_data);
558 0 : if (!err)
559 : break;
560 : }
561 :
562 0 : free_page((unsigned long)fs_names);
563 0 : return err;
564 : }
565 :
566 0 : void __init mount_root(void)
567 : {
568 : #ifdef CONFIG_ROOT_NFS
569 : if (ROOT_DEV == Root_NFS) {
570 : if (!mount_nfs_root())
571 : printk(KERN_ERR "VFS: Unable to mount root fs via NFS.\n");
572 : return;
573 : }
574 : #endif
575 : #ifdef CONFIG_CIFS_ROOT
576 : if (ROOT_DEV == Root_CIFS) {
577 : if (!mount_cifs_root())
578 : printk(KERN_ERR "VFS: Unable to mount root fs via SMB.\n");
579 : return;
580 : }
581 : #endif
582 0 : if (ROOT_DEV == 0 && root_device_name && root_fs_names) {
583 0 : if (mount_nodev_root() == 0)
584 : return;
585 : }
586 : #ifdef CONFIG_BLOCK
587 : {
588 0 : int err = create_dev("/dev/root", ROOT_DEV);
589 :
590 0 : if (err < 0)
591 0 : pr_emerg("Failed to create /dev/root: %d\n", err);
592 0 : mount_block_root("/dev/root", root_mountflags);
593 : }
594 : #endif
595 : }
596 :
597 : /*
598 : * Prepare the namespace - decide what/where to mount, load ramdisks, etc.
599 : */
600 0 : void __init prepare_namespace(void)
601 : {
602 0 : if (root_delay) {
603 0 : printk(KERN_INFO "Waiting %d sec before mounting root device...\n",
604 : root_delay);
605 0 : ssleep(root_delay);
606 : }
607 :
608 : /*
609 : * wait for the known devices to complete their probing
610 : *
611 : * Note: this is a potential source of long boot delays.
612 : * For example, it is not atypical to wait 5 seconds here
613 : * for the touchpad of a laptop to initialize.
614 : */
615 0 : wait_for_device_probe();
616 :
617 : md_run_setup();
618 :
619 0 : if (saved_root_name[0]) {
620 0 : root_device_name = saved_root_name;
621 0 : if (!strncmp(root_device_name, "mtd", 3) ||
622 0 : !strncmp(root_device_name, "ubi", 3)) {
623 0 : mount_block_root(root_device_name, root_mountflags);
624 0 : goto out;
625 : }
626 0 : ROOT_DEV = name_to_dev_t(root_device_name);
627 0 : if (strncmp(root_device_name, "/dev/", 5) == 0)
628 0 : root_device_name += 5;
629 : }
630 :
631 : if (initrd_load())
632 : goto out;
633 :
634 : /* wait for any asynchronous scanning to complete */
635 0 : if ((ROOT_DEV == 0) && root_wait) {
636 0 : printk(KERN_INFO "Waiting for root device %s...\n",
637 : saved_root_name);
638 0 : while (driver_probe_done() != 0 ||
639 0 : (ROOT_DEV = name_to_dev_t(saved_root_name)) == 0)
640 0 : msleep(5);
641 0 : async_synchronize_full();
642 : }
643 :
644 0 : mount_root();
645 : out:
646 : devtmpfs_mount();
647 0 : init_mount(".", "/", NULL, MS_MOVE, NULL);
648 0 : init_chroot(".");
649 0 : }
650 :
651 : static bool is_tmpfs;
652 1 : static int rootfs_init_fs_context(struct fs_context *fc)
653 : {
654 : if (IS_ENABLED(CONFIG_TMPFS) && is_tmpfs)
655 : return shmem_init_fs_context(fc);
656 :
657 1 : return ramfs_init_fs_context(fc);
658 : }
659 :
660 : struct file_system_type rootfs_fs_type = {
661 : .name = "rootfs",
662 : .init_fs_context = rootfs_init_fs_context,
663 : .kill_sb = kill_litter_super,
664 : };
665 :
666 1 : void __init init_rootfs(void)
667 : {
668 : if (IS_ENABLED(CONFIG_TMPFS) && !saved_root_name[0] &&
669 : (!root_fs_names || strstr(root_fs_names, "tmpfs")))
670 : is_tmpfs = true;
671 1 : }
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