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/genhd.h>
12 : #include <linux/mount.h>
13 : #include <linux/device.h>
14 : #include <linux/init.h>
15 : #include <linux/fs.h>
16 : #include <linux/initrd.h>
17 : #include <linux/async.h>
18 : #include <linux/fs_struct.h>
19 : #include <linux/slab.h>
20 : #include <linux/ramfs.h>
21 : #include <linux/shmem_fs.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 root_device_name;
33 : static char __initdata saved_root_name[64];
34 : static int root_wait;
35 :
36 : dev_t ROOT_DEV;
37 :
38 0 : static int __init load_ramdisk(char *str)
39 : {
40 0 : pr_warn("ignoring the deprecated load_ramdisk= option\n");
41 0 : return 1;
42 : }
43 : __setup("load_ramdisk=", load_ramdisk);
44 :
45 1 : static int __init readonly(char *str)
46 : {
47 1 : if (*str)
48 : return 0;
49 1 : root_mountflags |= MS_RDONLY;
50 1 : return 1;
51 : }
52 :
53 0 : static int __init readwrite(char *str)
54 : {
55 0 : if (*str)
56 : return 0;
57 0 : root_mountflags &= ~MS_RDONLY;
58 0 : return 1;
59 : }
60 :
61 : __setup("ro", readonly);
62 : __setup("rw", readwrite);
63 :
64 : #ifdef CONFIG_BLOCK
65 : struct uuidcmp {
66 : const char *uuid;
67 : int len;
68 : };
69 :
70 : /**
71 : * match_dev_by_uuid - callback for finding a partition using its uuid
72 : * @dev: device passed in by the caller
73 : * @data: opaque pointer to the desired struct uuidcmp to match
74 : *
75 : * Returns 1 if the device matches, and 0 otherwise.
76 : */
77 0 : static int match_dev_by_uuid(struct device *dev, const void *data)
78 : {
79 0 : struct block_device *bdev = dev_to_bdev(dev);
80 0 : const struct uuidcmp *cmp = data;
81 :
82 0 : if (!bdev->bd_meta_info ||
83 0 : strncasecmp(cmp->uuid, bdev->bd_meta_info->uuid, cmp->len))
84 0 : return 0;
85 : return 1;
86 : }
87 :
88 : /**
89 : * devt_from_partuuid - looks up the dev_t of a partition by its UUID
90 : * @uuid_str: char array containing ascii UUID
91 : *
92 : * The function will return the first partition which contains a matching
93 : * UUID value in its partition_meta_info struct. This does not search
94 : * by filesystem UUIDs.
95 : *
96 : * If @uuid_str is followed by a "/PARTNROFF=%d", then the number will be
97 : * extracted and used as an offset from the partition identified by the UUID.
98 : *
99 : * Returns the matching dev_t on success or 0 on failure.
100 : */
101 0 : static dev_t devt_from_partuuid(const char *uuid_str)
102 : {
103 0 : struct uuidcmp cmp;
104 0 : struct device *dev = NULL;
105 0 : dev_t devt = 0;
106 0 : int offset = 0;
107 0 : char *slash;
108 :
109 0 : cmp.uuid = uuid_str;
110 :
111 0 : slash = strchr(uuid_str, '/');
112 : /* Check for optional partition number offset attributes. */
113 0 : if (slash) {
114 0 : char c = 0;
115 :
116 : /* Explicitly fail on poor PARTUUID syntax. */
117 0 : if (sscanf(slash + 1, "PARTNROFF=%d%c", &offset, &c) != 1)
118 0 : goto clear_root_wait;
119 0 : cmp.len = slash - uuid_str;
120 : } else {
121 0 : cmp.len = strlen(uuid_str);
122 : }
123 :
124 0 : if (!cmp.len)
125 0 : goto clear_root_wait;
126 :
127 0 : dev = class_find_device(&block_class, NULL, &cmp, &match_dev_by_uuid);
128 0 : if (!dev)
129 : return 0;
130 :
131 0 : if (offset) {
132 : /*
133 : * Attempt to find the requested partition by adding an offset
134 : * to the partition number found by UUID.
135 : */
136 0 : struct block_device *part;
137 :
138 0 : part = bdget_disk(dev_to_disk(dev),
139 0 : dev_to_bdev(dev)->bd_partno + offset);
140 0 : if (part) {
141 0 : devt = part->bd_dev;
142 0 : bdput(part);
143 : }
144 : } else {
145 0 : devt = dev->devt;
146 : }
147 :
148 0 : put_device(dev);
149 0 : return devt;
150 :
151 0 : clear_root_wait:
152 0 : pr_err("VFS: PARTUUID= is invalid.\n"
153 : "Expected PARTUUID=<valid-uuid-id>[/PARTNROFF=%%d]\n");
154 0 : if (root_wait)
155 0 : pr_err("Disabling rootwait; root= is invalid.\n");
156 0 : root_wait = 0;
157 0 : return 0;
158 : }
159 :
160 : /**
161 : * match_dev_by_label - callback for finding a partition using its label
162 : * @dev: device passed in by the caller
163 : * @data: opaque pointer to the label to match
164 : *
165 : * Returns 1 if the device matches, and 0 otherwise.
166 : */
167 0 : static int match_dev_by_label(struct device *dev, const void *data)
168 : {
169 0 : struct block_device *bdev = dev_to_bdev(dev);
170 0 : const char *label = data;
171 :
172 0 : if (!bdev->bd_meta_info || strcmp(label, bdev->bd_meta_info->volname))
173 0 : return 0;
174 : return 1;
175 : }
176 :
177 0 : static dev_t devt_from_partlabel(const char *label)
178 : {
179 0 : struct device *dev;
180 0 : dev_t devt = 0;
181 :
182 0 : dev = class_find_device(&block_class, NULL, label, &match_dev_by_label);
183 0 : if (dev) {
184 0 : devt = dev->devt;
185 0 : put_device(dev);
186 : }
187 :
188 0 : return devt;
189 : }
190 :
191 1 : static dev_t devt_from_devname(const char *name)
192 : {
193 1 : dev_t devt = 0;
194 1 : int part;
195 1 : char s[32];
196 1 : char *p;
197 :
198 1 : if (strlen(name) > 31)
199 : return 0;
200 1 : strcpy(s, name);
201 5 : for (p = s; *p; p++) {
202 4 : if (*p == '/')
203 0 : *p = '!';
204 : }
205 :
206 1 : devt = blk_lookup_devt(s, 0);
207 1 : if (devt)
208 : return devt;
209 :
210 : /*
211 : * Try non-existent, but valid partition, which may only exist after
212 : * opening the device, like partitioned md devices.
213 : */
214 2 : while (p > s && isdigit(p[-1]))
215 1 : p--;
216 1 : if (p == s || !*p || *p == '0')
217 : return 0;
218 :
219 : /* try disk name without <part number> */
220 1 : part = simple_strtoul(p, NULL, 10);
221 1 : *p = '\0';
222 1 : devt = blk_lookup_devt(s, part);
223 1 : if (devt)
224 : return devt;
225 :
226 : /* try disk name without p<part number> */
227 0 : if (p < s + 2 || !isdigit(p[-2]) || p[-1] != 'p')
228 : return 0;
229 0 : p[-1] = '\0';
230 0 : return blk_lookup_devt(s, part);
231 : }
232 : #endif /* CONFIG_BLOCK */
233 :
234 0 : static dev_t devt_from_devnum(const char *name)
235 : {
236 0 : unsigned maj, min, offset;
237 0 : dev_t devt = 0;
238 0 : char *p, dummy;
239 :
240 0 : if (sscanf(name, "%u:%u%c", &maj, &min, &dummy) == 2 ||
241 0 : sscanf(name, "%u:%u:%u:%c", &maj, &min, &offset, &dummy) == 3) {
242 0 : devt = MKDEV(maj, min);
243 0 : if (maj != MAJOR(devt) || min != MINOR(devt))
244 0 : return 0;
245 : } else {
246 0 : devt = new_decode_dev(simple_strtoul(name, &p, 16));
247 0 : if (*p)
248 0 : return 0;
249 : }
250 :
251 : return devt;
252 : }
253 :
254 : /*
255 : * Convert a name into device number. We accept the following variants:
256 : *
257 : * 1) <hex_major><hex_minor> device number in hexadecimal represents itself
258 : * no leading 0x, for example b302.
259 : * 2) /dev/nfs represents Root_NFS (0xff)
260 : * 3) /dev/<disk_name> represents the device number of disk
261 : * 4) /dev/<disk_name><decimal> represents the device number
262 : * of partition - device number of disk plus the partition number
263 : * 5) /dev/<disk_name>p<decimal> - same as the above, that form is
264 : * used when disk name of partitioned disk ends on a digit.
265 : * 6) PARTUUID=00112233-4455-6677-8899-AABBCCDDEEFF representing the
266 : * unique id of a partition if the partition table provides it.
267 : * The UUID may be either an EFI/GPT UUID, or refer to an MSDOS
268 : * partition using the format SSSSSSSS-PP, where SSSSSSSS is a zero-
269 : * filled hex representation of the 32-bit "NT disk signature", and PP
270 : * is a zero-filled hex representation of the 1-based partition number.
271 : * 7) PARTUUID=<UUID>/PARTNROFF=<int> to select a partition in relation to
272 : * a partition with a known unique id.
273 : * 8) <major>:<minor> major and minor number of the device separated by
274 : * a colon.
275 : * 9) PARTLABEL=<name> with name being the GPT partition label.
276 : * MSDOS partitions do not support labels!
277 : * 10) /dev/cifs represents Root_CIFS (0xfe)
278 : *
279 : * If name doesn't have fall into the categories above, we return (0,0).
280 : * block_class is used to check if something is a disk name. If the disk
281 : * name contains slashes, the device name has them replaced with
282 : * bangs.
283 : */
284 1 : dev_t name_to_dev_t(const char *name)
285 : {
286 1 : if (strcmp(name, "/dev/nfs") == 0)
287 : return Root_NFS;
288 1 : if (strcmp(name, "/dev/cifs") == 0)
289 : return Root_CIFS;
290 1 : if (strcmp(name, "/dev/ram") == 0)
291 : return Root_RAM0;
292 : #ifdef CONFIG_BLOCK
293 1 : if (strncmp(name, "PARTUUID=", 9) == 0)
294 0 : return devt_from_partuuid(name + 9);
295 1 : if (strncmp(name, "PARTLABEL=", 10) == 0)
296 0 : return devt_from_partlabel(name + 10);
297 1 : if (strncmp(name, "/dev/", 5) == 0)
298 1 : return devt_from_devname(name + 5);
299 : #endif
300 0 : return devt_from_devnum(name);
301 : }
302 : EXPORT_SYMBOL_GPL(name_to_dev_t);
303 :
304 1 : static int __init root_dev_setup(char *line)
305 : {
306 1 : strlcpy(saved_root_name, line, sizeof(saved_root_name));
307 1 : return 1;
308 : }
309 :
310 : __setup("root=", root_dev_setup);
311 :
312 0 : static int __init rootwait_setup(char *str)
313 : {
314 0 : if (*str)
315 : return 0;
316 0 : root_wait = 1;
317 0 : return 1;
318 : }
319 :
320 : __setup("rootwait", rootwait_setup);
321 :
322 : static char * __initdata root_mount_data;
323 0 : static int __init root_data_setup(char *str)
324 : {
325 0 : root_mount_data = str;
326 0 : return 1;
327 : }
328 :
329 : static char * __initdata root_fs_names;
330 0 : static int __init fs_names_setup(char *str)
331 : {
332 0 : root_fs_names = str;
333 0 : return 1;
334 : }
335 :
336 : static unsigned int __initdata root_delay;
337 0 : static int __init root_delay_setup(char *str)
338 : {
339 0 : root_delay = simple_strtoul(str, NULL, 0);
340 0 : return 1;
341 : }
342 :
343 : __setup("rootflags=", root_data_setup);
344 : __setup("rootfstype=", fs_names_setup);
345 : __setup("rootdelay=", root_delay_setup);
346 :
347 1 : static void __init get_fs_names(char *page)
348 : {
349 1 : char *s = page;
350 :
351 1 : if (root_fs_names) {
352 0 : strcpy(page, root_fs_names);
353 0 : while (*s++) {
354 0 : if (s[-1] == ',')
355 0 : s[-1] = '\0';
356 : }
357 : } else {
358 1 : int len = get_filesystem_list(page);
359 1 : char *p, *next;
360 :
361 1 : page[len] = '\0';
362 20 : for (p = page-1; p; p = next) {
363 19 : next = strchr(++p, '\n');
364 19 : if (*p++ != '\t')
365 16 : continue;
366 18 : while ((*s++ = *p++) != '\n')
367 18 : ;
368 3 : s[-1] = '\0';
369 : }
370 : }
371 1 : *s = '\0';
372 1 : }
373 :
374 2 : static int __init do_mount_root(const char *name, const char *fs,
375 : const int flags, const void *data)
376 : {
377 2 : struct super_block *s;
378 2 : struct page *p = NULL;
379 2 : char *data_page = NULL;
380 2 : int ret;
381 :
382 2 : if (data) {
383 : /* init_mount() requires a full page as fifth argument */
384 0 : p = alloc_page(GFP_KERNEL);
385 0 : if (!p)
386 : return -ENOMEM;
387 0 : data_page = page_address(p);
388 : /* zero-pad. init_mount() will make sure it's terminated */
389 0 : strncpy(data_page, data, PAGE_SIZE);
390 : }
391 :
392 2 : ret = init_mount(name, "/root", fs, flags, data_page);
393 2 : if (ret)
394 1 : goto out;
395 :
396 1 : init_chdir("/root");
397 1 : s = current->fs->pwd.dentry->d_sb;
398 1 : ROOT_DEV = s->s_dev;
399 2 : printk(KERN_INFO
400 : "VFS: Mounted root (%s filesystem)%s on device %u:%u.\n",
401 1 : s->s_type->name,
402 1 : sb_rdonly(s) ? " readonly" : "",
403 1 : MAJOR(ROOT_DEV), MINOR(ROOT_DEV));
404 :
405 2 : out:
406 2 : if (p)
407 0 : put_page(p);
408 : return ret;
409 : }
410 :
411 1 : void __init mount_block_root(char *name, int flags)
412 : {
413 1 : struct page *page = alloc_page(GFP_KERNEL);
414 1 : char *fs_names = page_address(page);
415 1 : char *p;
416 1 : char b[BDEVNAME_SIZE];
417 :
418 1 : scnprintf(b, BDEVNAME_SIZE, "unknown-block(%u,%u)",
419 1 : MAJOR(ROOT_DEV), MINOR(ROOT_DEV));
420 1 : get_fs_names(fs_names);
421 1 : retry:
422 2 : for (p = fs_names; *p; p += strlen(p)+1) {
423 2 : int err = do_mount_root(name, p, flags, root_mount_data);
424 2 : switch (err) {
425 1 : case 0:
426 1 : goto out;
427 1 : case -EACCES:
428 : case -EINVAL:
429 1 : continue;
430 : }
431 : /*
432 : * Allow the user to distinguish between failed sys_open
433 : * and bad superblock on root device.
434 : * and give them a list of the available devices
435 : */
436 0 : printk("VFS: Cannot open root device \"%s\" or %s: error %d\n",
437 : root_device_name, b, err);
438 0 : printk("Please append a correct \"root=\" boot option; here are the available partitions:\n");
439 :
440 0 : printk_all_partitions();
441 : #ifdef CONFIG_DEBUG_BLOCK_EXT_DEVT
442 : printk("DEBUG_BLOCK_EXT_DEVT is enabled, you need to specify "
443 : "explicit textual name for \"root=\" boot option.\n");
444 : #endif
445 0 : panic("VFS: Unable to mount root fs on %s", b);
446 : }
447 0 : if (!(flags & SB_RDONLY)) {
448 0 : flags |= SB_RDONLY;
449 0 : goto retry;
450 : }
451 :
452 0 : printk("List of all partitions:\n");
453 0 : printk_all_partitions();
454 0 : printk("No filesystem could mount root, tried: ");
455 0 : for (p = fs_names; *p; p += strlen(p)+1)
456 0 : printk(" %s", p);
457 0 : printk("\n");
458 0 : panic("VFS: Unable to mount root fs on %s", b);
459 1 : out:
460 1 : put_page(page);
461 1 : }
462 :
463 : #ifdef CONFIG_ROOT_NFS
464 :
465 : #define NFSROOT_TIMEOUT_MIN 5
466 : #define NFSROOT_TIMEOUT_MAX 30
467 : #define NFSROOT_RETRY_MAX 5
468 :
469 : static int __init mount_nfs_root(void)
470 : {
471 : char *root_dev, *root_data;
472 : unsigned int timeout;
473 : int try, err;
474 :
475 : err = nfs_root_data(&root_dev, &root_data);
476 : if (err != 0)
477 : return 0;
478 :
479 : /*
480 : * The server or network may not be ready, so try several
481 : * times. Stop after a few tries in case the client wants
482 : * to fall back to other boot methods.
483 : */
484 : timeout = NFSROOT_TIMEOUT_MIN;
485 : for (try = 1; ; try++) {
486 : err = do_mount_root(root_dev, "nfs",
487 : root_mountflags, root_data);
488 : if (err == 0)
489 : return 1;
490 : if (try > NFSROOT_RETRY_MAX)
491 : break;
492 :
493 : /* Wait, in case the server refused us immediately */
494 : ssleep(timeout);
495 : timeout <<= 1;
496 : if (timeout > NFSROOT_TIMEOUT_MAX)
497 : timeout = NFSROOT_TIMEOUT_MAX;
498 : }
499 : return 0;
500 : }
501 : #endif
502 :
503 : #ifdef CONFIG_CIFS_ROOT
504 :
505 : extern int cifs_root_data(char **dev, char **opts);
506 :
507 : #define CIFSROOT_TIMEOUT_MIN 5
508 : #define CIFSROOT_TIMEOUT_MAX 30
509 : #define CIFSROOT_RETRY_MAX 5
510 :
511 : static int __init mount_cifs_root(void)
512 : {
513 : char *root_dev, *root_data;
514 : unsigned int timeout;
515 : int try, err;
516 :
517 : err = cifs_root_data(&root_dev, &root_data);
518 : if (err != 0)
519 : return 0;
520 :
521 : timeout = CIFSROOT_TIMEOUT_MIN;
522 : for (try = 1; ; try++) {
523 : err = do_mount_root(root_dev, "cifs", root_mountflags,
524 : root_data);
525 : if (err == 0)
526 : return 1;
527 : if (try > CIFSROOT_RETRY_MAX)
528 : break;
529 :
530 : ssleep(timeout);
531 : timeout <<= 1;
532 : if (timeout > CIFSROOT_TIMEOUT_MAX)
533 : timeout = CIFSROOT_TIMEOUT_MAX;
534 : }
535 : return 0;
536 : }
537 : #endif
538 :
539 1 : void __init mount_root(void)
540 : {
541 : #ifdef CONFIG_ROOT_NFS
542 : if (ROOT_DEV == Root_NFS) {
543 : if (!mount_nfs_root())
544 : printk(KERN_ERR "VFS: Unable to mount root fs via NFS.\n");
545 : return;
546 : }
547 : #endif
548 : #ifdef CONFIG_CIFS_ROOT
549 : if (ROOT_DEV == Root_CIFS) {
550 : if (!mount_cifs_root())
551 : printk(KERN_ERR "VFS: Unable to mount root fs via SMB.\n");
552 : return;
553 : }
554 : #endif
555 : #ifdef CONFIG_BLOCK
556 : {
557 1 : int err = create_dev("/dev/root", ROOT_DEV);
558 :
559 1 : if (err < 0)
560 0 : pr_emerg("Failed to create /dev/root: %d\n", err);
561 1 : mount_block_root("/dev/root", root_mountflags);
562 : }
563 : #endif
564 1 : }
565 :
566 : /*
567 : * Prepare the namespace - decide what/where to mount, load ramdisks, etc.
568 : */
569 1 : void __init prepare_namespace(void)
570 : {
571 1 : if (root_delay) {
572 0 : printk(KERN_INFO "Waiting %d sec before mounting root device...\n",
573 : root_delay);
574 0 : ssleep(root_delay);
575 : }
576 :
577 : /*
578 : * wait for the known devices to complete their probing
579 : *
580 : * Note: this is a potential source of long boot delays.
581 : * For example, it is not atypical to wait 5 seconds here
582 : * for the touchpad of a laptop to initialize.
583 : */
584 1 : wait_for_device_probe();
585 :
586 1 : md_run_setup();
587 :
588 1 : if (saved_root_name[0]) {
589 1 : root_device_name = saved_root_name;
590 1 : if (!strncmp(root_device_name, "mtd", 3) ||
591 1 : !strncmp(root_device_name, "ubi", 3)) {
592 0 : mount_block_root(root_device_name, root_mountflags);
593 0 : goto out;
594 : }
595 1 : ROOT_DEV = name_to_dev_t(root_device_name);
596 1 : if (strncmp(root_device_name, "/dev/", 5) == 0)
597 1 : root_device_name += 5;
598 : }
599 :
600 1 : if (initrd_load())
601 0 : goto out;
602 :
603 : /* wait for any asynchronous scanning to complete */
604 1 : if ((ROOT_DEV == 0) && root_wait) {
605 0 : printk(KERN_INFO "Waiting for root device %s...\n",
606 : saved_root_name);
607 0 : while (driver_probe_done() != 0 ||
608 0 : (ROOT_DEV = name_to_dev_t(saved_root_name)) == 0)
609 0 : msleep(5);
610 0 : async_synchronize_full();
611 : }
612 :
613 1 : mount_root();
614 1 : out:
615 1 : devtmpfs_mount();
616 1 : init_mount(".", "/", NULL, MS_MOVE, NULL);
617 1 : init_chroot(".");
618 1 : }
619 :
620 : static bool is_tmpfs;
621 1 : static int rootfs_init_fs_context(struct fs_context *fc)
622 : {
623 1 : if (IS_ENABLED(CONFIG_TMPFS) && is_tmpfs)
624 0 : return shmem_init_fs_context(fc);
625 :
626 1 : return ramfs_init_fs_context(fc);
627 : }
628 :
629 : struct file_system_type rootfs_fs_type = {
630 : .name = "rootfs",
631 : .init_fs_context = rootfs_init_fs_context,
632 : .kill_sb = kill_litter_super,
633 : };
634 :
635 1 : void __init init_rootfs(void)
636 : {
637 1 : if (IS_ENABLED(CONFIG_TMPFS) && !saved_root_name[0] &&
638 0 : (!root_fs_names || strstr(root_fs_names, "tmpfs")))
639 0 : is_tmpfs = true;
640 1 : }
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