1 // SPDX-License-Identifier: GPL-2.0
2 #include <linux/init.h>
3 #include <linux/async.h>
4 #include <linux/fs.h>
5 #include <linux/slab.h>
6 #include <linux/types.h>
7 #include <linux/fcntl.h>
8 #include <linux/delay.h>
9 #include <linux/string.h>
10 #include <linux/dirent.h>
11 #include <linux/syscalls.h>
12 #include <linux/utime.h>
13 #include <linux/file.h>
14 #include <linux/kstrtox.h>
15 #include <linux/memblock.h>
16 #include <linux/mm.h>
17 #include <linux/namei.h>
18 #include <linux/init_syscalls.h>
19 #include <linux/umh.h>
20 #include <linux/security.h>
21
22 #include "do_mounts.h"
23 #include "initramfs_internal.h"
24
25 static __initdata bool csum_present;
26 static __initdata u32 io_csum;
27
xwrite(struct file * file,const unsigned char * p,size_t count,loff_t * pos)28 static ssize_t __init xwrite(struct file *file, const unsigned char *p,
29 size_t count, loff_t *pos)
30 {
31 ssize_t out = 0;
32
33 /* sys_write only can write MAX_RW_COUNT aka 2G-4K bytes at most */
34 while (count) {
35 ssize_t rv = kernel_write(file, p, count, pos);
36
37 if (rv < 0) {
38 if (rv == -EINTR || rv == -EAGAIN)
39 continue;
40 return out ? out : rv;
41 } else if (rv == 0)
42 break;
43
44 if (csum_present) {
45 ssize_t i;
46
47 for (i = 0; i < rv; i++)
48 io_csum += p[i];
49 }
50
51 p += rv;
52 out += rv;
53 count -= rv;
54 }
55
56 return out;
57 }
58
59 static __initdata char *message;
error(char * x)60 static void __init error(char *x)
61 {
62 if (!message)
63 message = x;
64 }
65
66 #define panic_show_mem(fmt, ...) \
67 ({ show_mem(); panic(fmt, ##__VA_ARGS__); })
68
69 /* link hash */
70
71 #define N_ALIGN(len) ((((len) + 1) & ~3) + 2)
72
73 static __initdata struct hash {
74 int ino, minor, major;
75 umode_t mode;
76 struct hash *next;
77 char name[N_ALIGN(PATH_MAX)];
78 } *head[32];
79 static __initdata bool hardlink_seen;
80
hash(int major,int minor,int ino)81 static inline int hash(int major, int minor, int ino)
82 {
83 unsigned long tmp = ino + minor + (major << 3);
84 tmp += tmp >> 5;
85 return tmp & 31;
86 }
87
find_link(int major,int minor,int ino,umode_t mode,char * name)88 static char __init *find_link(int major, int minor, int ino,
89 umode_t mode, char *name)
90 {
91 struct hash **p, *q;
92 for (p = head + hash(major, minor, ino); *p; p = &(*p)->next) {
93 if ((*p)->ino != ino)
94 continue;
95 if ((*p)->minor != minor)
96 continue;
97 if ((*p)->major != major)
98 continue;
99 if (((*p)->mode ^ mode) & S_IFMT)
100 continue;
101 return (*p)->name;
102 }
103 q = kmalloc(sizeof(struct hash), GFP_KERNEL);
104 if (!q)
105 panic_show_mem("can't allocate link hash entry");
106 q->major = major;
107 q->minor = minor;
108 q->ino = ino;
109 q->mode = mode;
110 strcpy(q->name, name);
111 q->next = NULL;
112 *p = q;
113 hardlink_seen = true;
114 return NULL;
115 }
116
free_hash(void)117 static void __init free_hash(void)
118 {
119 struct hash **p, *q;
120 for (p = head; hardlink_seen && p < head + 32; p++) {
121 while (*p) {
122 q = *p;
123 *p = q->next;
124 kfree(q);
125 }
126 }
127 hardlink_seen = false;
128 }
129
130 #ifdef CONFIG_INITRAMFS_PRESERVE_MTIME
do_utime(char * filename,time64_t mtime)131 static void __init do_utime(char *filename, time64_t mtime)
132 {
133 struct timespec64 t[2] = { { .tv_sec = mtime }, { .tv_sec = mtime } };
134 init_utimes(filename, t);
135 }
136
do_utime_path(const struct path * path,time64_t mtime)137 static void __init do_utime_path(const struct path *path, time64_t mtime)
138 {
139 struct timespec64 t[2] = { { .tv_sec = mtime }, { .tv_sec = mtime } };
140 vfs_utimes(path, t);
141 }
142
143 static __initdata LIST_HEAD(dir_list);
144 struct dir_entry {
145 struct list_head list;
146 time64_t mtime;
147 char name[];
148 };
149
dir_add(const char * name,size_t nlen,time64_t mtime)150 static void __init dir_add(const char *name, size_t nlen, time64_t mtime)
151 {
152 struct dir_entry *de;
153
154 de = kmalloc(sizeof(struct dir_entry) + nlen, GFP_KERNEL);
155 if (!de)
156 panic_show_mem("can't allocate dir_entry buffer");
157 INIT_LIST_HEAD(&de->list);
158 strscpy(de->name, name, nlen);
159 de->mtime = mtime;
160 list_add(&de->list, &dir_list);
161 }
162
dir_utime(void)163 static void __init dir_utime(void)
164 {
165 struct dir_entry *de, *tmp;
166 list_for_each_entry_safe(de, tmp, &dir_list, list) {
167 list_del(&de->list);
168 do_utime(de->name, de->mtime);
169 kfree(de);
170 }
171 }
172 #else
do_utime(char * filename,time64_t mtime)173 static void __init do_utime(char *filename, time64_t mtime) {}
do_utime_path(const struct path * path,time64_t mtime)174 static void __init do_utime_path(const struct path *path, time64_t mtime) {}
dir_add(const char * name,size_t nlen,time64_t mtime)175 static void __init dir_add(const char *name, size_t nlen, time64_t mtime) {}
dir_utime(void)176 static void __init dir_utime(void) {}
177 #endif
178
179 static __initdata time64_t mtime;
180
181 /* cpio header parsing */
182
183 static __initdata unsigned long ino, major, minor, nlink;
184 static __initdata umode_t mode;
185 static __initdata unsigned long body_len, name_len;
186 static __initdata uid_t uid;
187 static __initdata gid_t gid;
188 static __initdata unsigned rdev;
189 static __initdata u32 hdr_csum;
190
parse_header(char * s)191 static void __init parse_header(char *s)
192 {
193 unsigned long parsed[13];
194 int i;
195
196 for (i = 0, s += 6; i < 13; i++, s += 8)
197 parsed[i] = simple_strntoul(s, NULL, 16, 8);
198
199 ino = parsed[0];
200 mode = parsed[1];
201 uid = parsed[2];
202 gid = parsed[3];
203 nlink = parsed[4];
204 mtime = parsed[5]; /* breaks in y2106 */
205 body_len = parsed[6];
206 major = parsed[7];
207 minor = parsed[8];
208 rdev = new_encode_dev(MKDEV(parsed[9], parsed[10]));
209 name_len = parsed[11];
210 hdr_csum = parsed[12];
211 }
212
213 /* FSM */
214
215 static __initdata enum state {
216 Start,
217 Collect,
218 GotHeader,
219 SkipIt,
220 GotName,
221 CopyFile,
222 GotSymlink,
223 Reset
224 } state, next_state;
225
226 static __initdata char *victim;
227 static unsigned long byte_count __initdata;
228 static __initdata loff_t this_header, next_header;
229
eat(unsigned n)230 static inline void __init eat(unsigned n)
231 {
232 victim += n;
233 this_header += n;
234 byte_count -= n;
235 }
236
237 static __initdata char *collected;
238 static long remains __initdata;
239 static __initdata char *collect;
240
read_into(char * buf,unsigned size,enum state next)241 static void __init read_into(char *buf, unsigned size, enum state next)
242 {
243 if (byte_count >= size) {
244 collected = victim;
245 eat(size);
246 state = next;
247 } else {
248 collect = collected = buf;
249 remains = size;
250 next_state = next;
251 state = Collect;
252 }
253 }
254
255 static __initdata char *header_buf, *symlink_buf, *name_buf;
256
do_start(void)257 static int __init do_start(void)
258 {
259 read_into(header_buf, CPIO_HDRLEN, GotHeader);
260 return 0;
261 }
262
do_collect(void)263 static int __init do_collect(void)
264 {
265 unsigned long n = remains;
266 if (byte_count < n)
267 n = byte_count;
268 memcpy(collect, victim, n);
269 eat(n);
270 collect += n;
271 if ((remains -= n) != 0)
272 return 1;
273 state = next_state;
274 return 0;
275 }
276
do_header(void)277 static int __init do_header(void)
278 {
279 if (!memcmp(collected, "070701", 6)) {
280 csum_present = false;
281 } else if (!memcmp(collected, "070702", 6)) {
282 csum_present = true;
283 } else {
284 if (memcmp(collected, "070707", 6) == 0)
285 error("incorrect cpio method used: use -H newc option");
286 else
287 error("no cpio magic");
288 return 1;
289 }
290 parse_header(collected);
291 next_header = this_header + N_ALIGN(name_len) + body_len;
292 next_header = (next_header + 3) & ~3;
293 state = SkipIt;
294 if (name_len <= 0 || name_len > PATH_MAX)
295 return 0;
296 if (S_ISLNK(mode)) {
297 if (body_len > PATH_MAX)
298 return 0;
299 collect = collected = symlink_buf;
300 remains = N_ALIGN(name_len) + body_len;
301 next_state = GotSymlink;
302 state = Collect;
303 return 0;
304 }
305 if (S_ISREG(mode) || !body_len)
306 read_into(name_buf, N_ALIGN(name_len), GotName);
307 return 0;
308 }
309
do_skip(void)310 static int __init do_skip(void)
311 {
312 if (this_header + byte_count < next_header) {
313 eat(byte_count);
314 return 1;
315 } else {
316 eat(next_header - this_header);
317 state = next_state;
318 return 0;
319 }
320 }
321
do_reset(void)322 static int __init do_reset(void)
323 {
324 while (byte_count && *victim == '\0')
325 eat(1);
326 if (byte_count && (this_header & 3))
327 error("broken padding");
328 return 1;
329 }
330
clean_path(char * path,umode_t fmode)331 static void __init clean_path(char *path, umode_t fmode)
332 {
333 struct kstat st;
334
335 if (!init_stat(path, &st, AT_SYMLINK_NOFOLLOW) &&
336 (st.mode ^ fmode) & S_IFMT) {
337 if (S_ISDIR(st.mode))
338 init_rmdir(path);
339 else
340 init_unlink(path);
341 }
342 }
343
maybe_link(void)344 static int __init maybe_link(void)
345 {
346 if (nlink >= 2) {
347 char *old = find_link(major, minor, ino, mode, collected);
348 if (old) {
349 clean_path(collected, 0);
350 return (init_link(old, collected) < 0) ? -1 : 1;
351 }
352 }
353 return 0;
354 }
355
356 static __initdata struct file *wfile;
357 static __initdata loff_t wfile_pos;
358
do_name(void)359 static int __init do_name(void)
360 {
361 state = SkipIt;
362 next_state = Reset;
363
364 /* name_len > 0 && name_len <= PATH_MAX checked in do_header */
365 if (collected[name_len - 1] != '\0') {
366 pr_err("initramfs name without nulterm: %.*s\n",
367 (int)name_len, collected);
368 error("malformed archive");
369 return 1;
370 }
371
372 if (strcmp(collected, "TRAILER!!!") == 0) {
373 free_hash();
374 return 0;
375 }
376 clean_path(collected, mode);
377 if (S_ISREG(mode)) {
378 int ml = maybe_link();
379 if (ml >= 0) {
380 int openflags = O_WRONLY|O_CREAT|O_LARGEFILE;
381 if (ml != 1)
382 openflags |= O_TRUNC;
383 wfile = filp_open(collected, openflags, mode);
384 if (IS_ERR(wfile))
385 return 0;
386 wfile_pos = 0;
387 io_csum = 0;
388
389 vfs_fchown(wfile, uid, gid);
390 vfs_fchmod(wfile, mode);
391 if (body_len)
392 vfs_truncate(&wfile->f_path, body_len);
393 state = CopyFile;
394 }
395 } else if (S_ISDIR(mode)) {
396 init_mkdir(collected, mode);
397 init_chown(collected, uid, gid, 0);
398 init_chmod(collected, mode);
399 dir_add(collected, name_len, mtime);
400 } else if (S_ISBLK(mode) || S_ISCHR(mode) ||
401 S_ISFIFO(mode) || S_ISSOCK(mode)) {
402 if (maybe_link() == 0) {
403 init_mknod(collected, mode, rdev);
404 init_chown(collected, uid, gid, 0);
405 init_chmod(collected, mode);
406 do_utime(collected, mtime);
407 }
408 }
409 return 0;
410 }
411
do_copy(void)412 static int __init do_copy(void)
413 {
414 if (byte_count >= body_len) {
415 if (xwrite(wfile, victim, body_len, &wfile_pos) != body_len)
416 error("write error");
417
418 do_utime_path(&wfile->f_path, mtime);
419 fput(wfile);
420 if (csum_present && io_csum != hdr_csum)
421 error("bad data checksum");
422 eat(body_len);
423 state = SkipIt;
424 return 0;
425 } else {
426 if (xwrite(wfile, victim, byte_count, &wfile_pos) != byte_count)
427 error("write error");
428 body_len -= byte_count;
429 eat(byte_count);
430 return 1;
431 }
432 }
433
do_symlink(void)434 static int __init do_symlink(void)
435 {
436 if (collected[name_len - 1] != '\0') {
437 pr_err("initramfs symlink without nulterm: %.*s\n",
438 (int)name_len, collected);
439 error("malformed archive");
440 return 1;
441 }
442 collected[N_ALIGN(name_len) + body_len] = '\0';
443 clean_path(collected, 0);
444 init_symlink(collected + N_ALIGN(name_len), collected);
445 init_chown(collected, uid, gid, AT_SYMLINK_NOFOLLOW);
446 do_utime(collected, mtime);
447 state = SkipIt;
448 next_state = Reset;
449 return 0;
450 }
451
452 static __initdata int (*actions[])(void) = {
453 [Start] = do_start,
454 [Collect] = do_collect,
455 [GotHeader] = do_header,
456 [SkipIt] = do_skip,
457 [GotName] = do_name,
458 [CopyFile] = do_copy,
459 [GotSymlink] = do_symlink,
460 [Reset] = do_reset,
461 };
462
write_buffer(char * buf,unsigned long len)463 static long __init write_buffer(char *buf, unsigned long len)
464 {
465 byte_count = len;
466 victim = buf;
467
468 while (!actions[state]())
469 ;
470 return len - byte_count;
471 }
472
flush_buffer(void * bufv,unsigned long len)473 static long __init flush_buffer(void *bufv, unsigned long len)
474 {
475 char *buf = bufv;
476 long written;
477 long origLen = len;
478 if (message)
479 return -1;
480 while ((written = write_buffer(buf, len)) < len && !message) {
481 char c = buf[written];
482 if (c == '0') {
483 buf += written;
484 len -= written;
485 state = Start;
486 } else if (c == 0) {
487 buf += written;
488 len -= written;
489 state = Reset;
490 } else
491 error("junk within compressed archive");
492 }
493 return origLen;
494 }
495
496 static unsigned long my_inptr __initdata; /* index of next byte to be processed in inbuf */
497
498 #include <linux/decompress/generic.h>
499
500 /**
501 * unpack_to_rootfs - decompress and extract an initramfs archive
502 * @buf: input initramfs archive to extract
503 * @len: length of initramfs data to process
504 *
505 * Returns: NULL for success or an error message string
506 *
507 * This symbol shouldn't be used externally. It's available for unit tests.
508 */
unpack_to_rootfs(char * buf,unsigned long len)509 char * __init unpack_to_rootfs(char *buf, unsigned long len)
510 {
511 long written;
512 decompress_fn decompress;
513 const char *compress_name;
514 struct {
515 char header[CPIO_HDRLEN];
516 char symlink[PATH_MAX + N_ALIGN(PATH_MAX) + 1];
517 char name[N_ALIGN(PATH_MAX)];
518 } *bufs = kmalloc(sizeof(*bufs), GFP_KERNEL);
519
520 if (!bufs)
521 panic_show_mem("can't allocate buffers");
522
523 header_buf = bufs->header;
524 symlink_buf = bufs->symlink;
525 name_buf = bufs->name;
526
527 state = Start;
528 this_header = 0;
529 message = NULL;
530 while (!message && len) {
531 loff_t saved_offset = this_header;
532 if (*buf == '0' && !(this_header & 3)) {
533 state = Start;
534 written = write_buffer(buf, len);
535 buf += written;
536 len -= written;
537 continue;
538 }
539 if (!*buf) {
540 buf++;
541 len--;
542 this_header++;
543 continue;
544 }
545 this_header = 0;
546 decompress = decompress_method(buf, len, &compress_name);
547 pr_debug("Detected %s compressed data\n", compress_name);
548 if (decompress) {
549 int res = decompress(buf, len, NULL, flush_buffer, NULL,
550 &my_inptr, error);
551 if (res)
552 error("decompressor failed");
553 } else if (compress_name) {
554 pr_err("compression method %s not configured\n",
555 compress_name);
556 error("decompressor failed");
557 } else
558 error("invalid magic at start of compressed archive");
559 if (state != Reset)
560 error("junk at the end of compressed archive");
561 this_header = saved_offset + my_inptr;
562 buf += my_inptr;
563 len -= my_inptr;
564 }
565 dir_utime();
566 /* free any hardlink state collected without optional TRAILER!!! */
567 free_hash();
568 kfree(bufs);
569 return message;
570 }
571
572 static int __initdata do_retain_initrd;
573
retain_initrd_param(char * str)574 static int __init retain_initrd_param(char *str)
575 {
576 if (*str)
577 return 0;
578 do_retain_initrd = 1;
579 return 1;
580 }
581 __setup("retain_initrd", retain_initrd_param);
582
583 #ifdef CONFIG_ARCH_HAS_KEEPINITRD
keepinitrd_setup(char * __unused)584 static int __init keepinitrd_setup(char *__unused)
585 {
586 do_retain_initrd = 1;
587 return 1;
588 }
589 __setup("keepinitrd", keepinitrd_setup);
590 #endif
591
592 static bool __initdata initramfs_async = true;
initramfs_async_setup(char * str)593 static int __init initramfs_async_setup(char *str)
594 {
595 return kstrtobool(str, &initramfs_async) == 0;
596 }
597 __setup("initramfs_async=", initramfs_async_setup);
598
599 extern char __initramfs_start[];
600 extern unsigned long __initramfs_size;
601 #include <linux/initrd.h>
602 #include <linux/kexec.h>
603
604 static BIN_ATTR(initrd, 0440, sysfs_bin_attr_simple_read, NULL, 0);
605
reserve_initrd_mem(void)606 void __init reserve_initrd_mem(void)
607 {
608 phys_addr_t start;
609 unsigned long size;
610
611 /* Ignore the virtul address computed during device tree parsing */
612 initrd_start = initrd_end = 0;
613
614 if (!phys_initrd_size)
615 return;
616 /*
617 * Round the memory region to page boundaries as per free_initrd_mem()
618 * This allows us to detect whether the pages overlapping the initrd
619 * are in use, but more importantly, reserves the entire set of pages
620 * as we don't want these pages allocated for other purposes.
621 */
622 start = round_down(phys_initrd_start, PAGE_SIZE);
623 size = phys_initrd_size + (phys_initrd_start - start);
624 size = round_up(size, PAGE_SIZE);
625
626 if (!memblock_is_region_memory(start, size)) {
627 pr_err("INITRD: 0x%08llx+0x%08lx is not a memory region",
628 (u64)start, size);
629 goto disable;
630 }
631
632 if (memblock_is_region_reserved(start, size)) {
633 pr_err("INITRD: 0x%08llx+0x%08lx overlaps in-use memory region\n",
634 (u64)start, size);
635 goto disable;
636 }
637
638 memblock_reserve(start, size);
639 /* Now convert initrd to virtual addresses */
640 initrd_start = (unsigned long)__va(phys_initrd_start);
641 initrd_end = initrd_start + phys_initrd_size;
642 initrd_below_start_ok = 1;
643
644 return;
645 disable:
646 pr_cont(" - disabling initrd\n");
647 initrd_start = 0;
648 initrd_end = 0;
649 }
650
free_initrd_mem(unsigned long start,unsigned long end)651 void __weak __init free_initrd_mem(unsigned long start, unsigned long end)
652 {
653 #ifdef CONFIG_ARCH_KEEP_MEMBLOCK
654 unsigned long aligned_start = ALIGN_DOWN(start, PAGE_SIZE);
655 unsigned long aligned_end = ALIGN(end, PAGE_SIZE);
656
657 memblock_free((void *)aligned_start, aligned_end - aligned_start);
658 #endif
659
660 free_reserved_area((void *)start, (void *)end, POISON_FREE_INITMEM,
661 "initrd");
662 }
663
664 #ifdef CONFIG_CRASH_RESERVE
kexec_free_initrd(void)665 static bool __init kexec_free_initrd(void)
666 {
667 unsigned long crashk_start = (unsigned long)__va(crashk_res.start);
668 unsigned long crashk_end = (unsigned long)__va(crashk_res.end);
669
670 /*
671 * If the initrd region is overlapped with crashkernel reserved region,
672 * free only memory that is not part of crashkernel region.
673 */
674 if (initrd_start >= crashk_end || initrd_end <= crashk_start)
675 return false;
676
677 /*
678 * Initialize initrd memory region since the kexec boot does not do.
679 */
680 memset((void *)initrd_start, 0, initrd_end - initrd_start);
681 if (initrd_start < crashk_start)
682 free_initrd_mem(initrd_start, crashk_start);
683 if (initrd_end > crashk_end)
684 free_initrd_mem(crashk_end, initrd_end);
685 return true;
686 }
687 #else
kexec_free_initrd(void)688 static inline bool kexec_free_initrd(void)
689 {
690 return false;
691 }
692 #endif /* CONFIG_KEXEC_CORE */
693
694 #ifdef CONFIG_BLK_DEV_RAM
populate_initrd_image(char * err)695 static void __init populate_initrd_image(char *err)
696 {
697 ssize_t written;
698 struct file *file;
699 loff_t pos = 0;
700
701 printk(KERN_INFO "rootfs image is not initramfs (%s); looks like an initrd\n",
702 err);
703 file = filp_open("/initrd.image", O_WRONLY|O_CREAT|O_LARGEFILE, 0700);
704 if (IS_ERR(file))
705 return;
706
707 written = xwrite(file, (char *)initrd_start, initrd_end - initrd_start,
708 &pos);
709 if (written != initrd_end - initrd_start)
710 pr_err("/initrd.image: incomplete write (%zd != %ld)\n",
711 written, initrd_end - initrd_start);
712 fput(file);
713 }
714 #endif /* CONFIG_BLK_DEV_RAM */
715
do_populate_rootfs(void * unused,async_cookie_t cookie)716 static void __init do_populate_rootfs(void *unused, async_cookie_t cookie)
717 {
718 /* Load the built in initramfs */
719 char *err = unpack_to_rootfs(__initramfs_start, __initramfs_size);
720 if (err)
721 panic_show_mem("%s", err); /* Failed to decompress INTERNAL initramfs */
722
723 if (!initrd_start || IS_ENABLED(CONFIG_INITRAMFS_FORCE))
724 goto done;
725
726 if (IS_ENABLED(CONFIG_BLK_DEV_RAM))
727 printk(KERN_INFO "Trying to unpack rootfs image as initramfs...\n");
728 else
729 printk(KERN_INFO "Unpacking initramfs...\n");
730
731 err = unpack_to_rootfs((char *)initrd_start, initrd_end - initrd_start);
732 if (err) {
733 #ifdef CONFIG_BLK_DEV_RAM
734 populate_initrd_image(err);
735 #else
736 printk(KERN_EMERG "Initramfs unpacking failed: %s\n", err);
737 #endif
738 }
739
740 done:
741 security_initramfs_populated();
742
743 /*
744 * If the initrd region is overlapped with crashkernel reserved region,
745 * free only memory that is not part of crashkernel region.
746 */
747 if (!do_retain_initrd && initrd_start && !kexec_free_initrd()) {
748 free_initrd_mem(initrd_start, initrd_end);
749 } else if (do_retain_initrd && initrd_start) {
750 bin_attr_initrd.size = initrd_end - initrd_start;
751 bin_attr_initrd.private = (void *)initrd_start;
752 if (sysfs_create_bin_file(firmware_kobj, &bin_attr_initrd))
753 pr_err("Failed to create initrd sysfs file");
754 }
755 initrd_start = 0;
756 initrd_end = 0;
757
758 init_flush_fput();
759 }
760
761 static ASYNC_DOMAIN_EXCLUSIVE(initramfs_domain);
762 static async_cookie_t initramfs_cookie;
763
wait_for_initramfs(void)764 void wait_for_initramfs(void)
765 {
766 if (!initramfs_cookie) {
767 /*
768 * Something before rootfs_initcall wants to access
769 * the filesystem/initramfs. Probably a bug. Make a
770 * note, avoid deadlocking the machine, and let the
771 * caller's access fail as it used to.
772 */
773 pr_warn_once("wait_for_initramfs() called before rootfs_initcalls\n");
774 return;
775 }
776 async_synchronize_cookie_domain(initramfs_cookie + 1, &initramfs_domain);
777 }
778 EXPORT_SYMBOL_GPL(wait_for_initramfs);
779
populate_rootfs(void)780 static int __init populate_rootfs(void)
781 {
782 initramfs_cookie = async_schedule_domain(do_populate_rootfs, NULL,
783 &initramfs_domain);
784 usermodehelper_enable();
785 if (!initramfs_async)
786 wait_for_initramfs();
787 return 0;
788 }
789 rootfs_initcall(populate_rootfs);
790