1 // SPDX-License-Identifier: GPL-2.0
2 #include <linux/init.h>
3 #include <linux/async.h>
4 #include <linux/export.h>
5 #include <linux/fs.h>
6 #include <linux/slab.h>
7 #include <linux/types.h>
8 #include <linux/fcntl.h>
9 #include <linux/delay.h>
10 #include <linux/string.h>
11 #include <linux/dirent.h>
12 #include <linux/syscalls.h>
13 #include <linux/utime.h>
14 #include <linux/file.h>
15 #include <linux/kstrtox.h>
16 #include <linux/memblock.h>
17 #include <linux/mm.h>
18 #include <linux/namei.h>
19 #include <linux/init_syscalls.h>
20 #include <linux/umh.h>
21 #include <linux/security.h>
22
23 #include "do_mounts.h"
24 #include "initramfs_internal.h"
25
26 static __initdata bool csum_present;
27 static __initdata u32 io_csum;
28
xwrite(struct file * file,const unsigned char * p,size_t count,loff_t * pos)29 static ssize_t __init xwrite(struct file *file, const unsigned char *p,
30 size_t count, loff_t *pos)
31 {
32 ssize_t out = 0;
33
34 /* sys_write only can write MAX_RW_COUNT aka 2G-4K bytes at most */
35 while (count) {
36 ssize_t rv = kernel_write(file, p, count, pos);
37
38 if (rv < 0) {
39 if (rv == -EINTR || rv == -EAGAIN)
40 continue;
41 return out ? out : rv;
42 } else if (rv == 0)
43 break;
44
45 if (csum_present) {
46 ssize_t i;
47
48 for (i = 0; i < rv; i++)
49 io_csum += p[i];
50 }
51
52 p += rv;
53 out += rv;
54 count -= rv;
55 }
56
57 return out;
58 }
59
60 static __initdata char *message;
error(char * x)61 static void __init error(char *x)
62 {
63 if (!message)
64 message = x;
65 }
66
67 #define panic_show_mem(fmt, ...) \
68 ({ show_mem(); panic(fmt, ##__VA_ARGS__); })
69
70 /* link hash */
71
72 #define N_ALIGN(len) ((((len) + 1) & ~3) + 2)
73
74 static __initdata struct hash {
75 int ino, minor, major;
76 umode_t mode;
77 struct hash *next;
78 char name[N_ALIGN(PATH_MAX)];
79 } *head[32];
80 static __initdata bool hardlink_seen;
81
hash(int major,int minor,int ino)82 static inline int hash(int major, int minor, int ino)
83 {
84 unsigned long tmp = ino + minor + (major << 3);
85 tmp += tmp >> 5;
86 return tmp & 31;
87 }
88
find_link(int major,int minor,int ino,umode_t mode,char * name)89 static char __init *find_link(int major, int minor, int ino,
90 umode_t mode, char *name)
91 {
92 struct hash **p, *q;
93 for (p = head + hash(major, minor, ino); *p; p = &(*p)->next) {
94 if ((*p)->ino != ino)
95 continue;
96 if ((*p)->minor != minor)
97 continue;
98 if ((*p)->major != major)
99 continue;
100 if (((*p)->mode ^ mode) & S_IFMT)
101 continue;
102 return (*p)->name;
103 }
104 q = kmalloc(sizeof(struct hash), GFP_KERNEL);
105 if (!q)
106 panic_show_mem("can't allocate link hash entry");
107 q->major = major;
108 q->minor = minor;
109 q->ino = ino;
110 q->mode = mode;
111 strcpy(q->name, name);
112 q->next = NULL;
113 *p = q;
114 hardlink_seen = true;
115 return NULL;
116 }
117
free_hash(void)118 static void __init free_hash(void)
119 {
120 struct hash **p, *q;
121 for (p = head; hardlink_seen && p < head + 32; p++) {
122 while (*p) {
123 q = *p;
124 *p = q->next;
125 kfree(q);
126 }
127 }
128 hardlink_seen = false;
129 }
130
131 #ifdef CONFIG_INITRAMFS_PRESERVE_MTIME
do_utime(char * filename,time64_t mtime)132 static void __init do_utime(char *filename, time64_t mtime)
133 {
134 struct timespec64 t[2] = { { .tv_sec = mtime }, { .tv_sec = mtime } };
135 init_utimes(filename, t);
136 }
137
do_utime_path(const struct path * path,time64_t mtime)138 static void __init do_utime_path(const struct path *path, time64_t mtime)
139 {
140 struct timespec64 t[2] = { { .tv_sec = mtime }, { .tv_sec = mtime } };
141 vfs_utimes(path, t);
142 }
143
144 static __initdata LIST_HEAD(dir_list);
145 struct dir_entry {
146 struct list_head list;
147 time64_t mtime;
148 char name[];
149 };
150
dir_add(const char * name,size_t nlen,time64_t mtime)151 static void __init dir_add(const char *name, size_t nlen, time64_t mtime)
152 {
153 struct dir_entry *de;
154
155 de = kmalloc(sizeof(struct dir_entry) + nlen, GFP_KERNEL);
156 if (!de)
157 panic_show_mem("can't allocate dir_entry buffer");
158 INIT_LIST_HEAD(&de->list);
159 strscpy(de->name, name, nlen);
160 de->mtime = mtime;
161 list_add(&de->list, &dir_list);
162 }
163
dir_utime(void)164 static void __init dir_utime(void)
165 {
166 struct dir_entry *de, *tmp;
167 list_for_each_entry_safe(de, tmp, &dir_list, list) {
168 list_del(&de->list);
169 do_utime(de->name, de->mtime);
170 kfree(de);
171 }
172 }
173 #else
do_utime(char * filename,time64_t mtime)174 static void __init do_utime(char *filename, time64_t mtime) {}
do_utime_path(const struct path * path,time64_t mtime)175 static void __init do_utime_path(const struct path *path, time64_t mtime) {}
dir_add(const char * name,size_t nlen,time64_t mtime)176 static void __init dir_add(const char *name, size_t nlen, time64_t mtime) {}
dir_utime(void)177 static void __init dir_utime(void) {}
178 #endif
179
180 static __initdata time64_t mtime;
181
182 /* cpio header parsing */
183
184 static __initdata unsigned long ino, major, minor, nlink;
185 static __initdata umode_t mode;
186 static __initdata unsigned long body_len, name_len;
187 static __initdata uid_t uid;
188 static __initdata gid_t gid;
189 static __initdata unsigned rdev;
190 static __initdata u32 hdr_csum;
191
parse_header(char * s)192 static void __init parse_header(char *s)
193 {
194 unsigned long parsed[13];
195 int i;
196
197 for (i = 0, s += 6; i < 13; i++, s += 8)
198 parsed[i] = simple_strntoul(s, NULL, 16, 8);
199
200 ino = parsed[0];
201 mode = parsed[1];
202 uid = parsed[2];
203 gid = parsed[3];
204 nlink = parsed[4];
205 mtime = parsed[5]; /* breaks in y2106 */
206 body_len = parsed[6];
207 major = parsed[7];
208 minor = parsed[8];
209 rdev = new_encode_dev(MKDEV(parsed[9], parsed[10]));
210 name_len = parsed[11];
211 hdr_csum = parsed[12];
212 }
213
214 /* FSM */
215
216 static __initdata enum state {
217 Start,
218 Collect,
219 GotHeader,
220 SkipIt,
221 GotName,
222 CopyFile,
223 GotSymlink,
224 Reset
225 } state, next_state;
226
227 static __initdata char *victim;
228 static unsigned long byte_count __initdata;
229 static __initdata loff_t this_header, next_header;
230
eat(unsigned n)231 static inline void __init eat(unsigned n)
232 {
233 victim += n;
234 this_header += n;
235 byte_count -= n;
236 }
237
238 static __initdata char *collected;
239 static long remains __initdata;
240 static __initdata char *collect;
241
read_into(char * buf,unsigned size,enum state next)242 static void __init read_into(char *buf, unsigned size, enum state next)
243 {
244 if (byte_count >= size) {
245 collected = victim;
246 eat(size);
247 state = next;
248 } else {
249 collect = collected = buf;
250 remains = size;
251 next_state = next;
252 state = Collect;
253 }
254 }
255
256 static __initdata char *header_buf, *symlink_buf, *name_buf;
257
do_start(void)258 static int __init do_start(void)
259 {
260 read_into(header_buf, CPIO_HDRLEN, GotHeader);
261 return 0;
262 }
263
do_collect(void)264 static int __init do_collect(void)
265 {
266 unsigned long n = remains;
267 if (byte_count < n)
268 n = byte_count;
269 memcpy(collect, victim, n);
270 eat(n);
271 collect += n;
272 if ((remains -= n) != 0)
273 return 1;
274 state = next_state;
275 return 0;
276 }
277
do_header(void)278 static int __init do_header(void)
279 {
280 if (!memcmp(collected, "070701", 6)) {
281 csum_present = false;
282 } else if (!memcmp(collected, "070702", 6)) {
283 csum_present = true;
284 } else {
285 if (memcmp(collected, "070707", 6) == 0)
286 error("incorrect cpio method used: use -H newc option");
287 else
288 error("no cpio magic");
289 return 1;
290 }
291 parse_header(collected);
292 next_header = this_header + N_ALIGN(name_len) + body_len;
293 next_header = (next_header + 3) & ~3;
294 state = SkipIt;
295 if (name_len <= 0 || name_len > PATH_MAX)
296 return 0;
297 if (S_ISLNK(mode)) {
298 if (body_len > PATH_MAX)
299 return 0;
300 collect = collected = symlink_buf;
301 remains = N_ALIGN(name_len) + body_len;
302 next_state = GotSymlink;
303 state = Collect;
304 return 0;
305 }
306 if (S_ISREG(mode) || !body_len)
307 read_into(name_buf, N_ALIGN(name_len), GotName);
308 return 0;
309 }
310
do_skip(void)311 static int __init do_skip(void)
312 {
313 if (this_header + byte_count < next_header) {
314 eat(byte_count);
315 return 1;
316 } else {
317 eat(next_header - this_header);
318 state = next_state;
319 return 0;
320 }
321 }
322
do_reset(void)323 static int __init do_reset(void)
324 {
325 while (byte_count && *victim == '\0')
326 eat(1);
327 if (byte_count && (this_header & 3))
328 error("broken padding");
329 return 1;
330 }
331
clean_path(char * path,umode_t fmode)332 static void __init clean_path(char *path, umode_t fmode)
333 {
334 struct kstat st;
335
336 if (!init_stat(path, &st, AT_SYMLINK_NOFOLLOW) &&
337 (st.mode ^ fmode) & S_IFMT) {
338 if (S_ISDIR(st.mode))
339 init_rmdir(path);
340 else
341 init_unlink(path);
342 }
343 }
344
maybe_link(void)345 static int __init maybe_link(void)
346 {
347 if (nlink >= 2) {
348 char *old = find_link(major, minor, ino, mode, collected);
349 if (old) {
350 clean_path(collected, 0);
351 return (init_link(old, collected) < 0) ? -1 : 1;
352 }
353 }
354 return 0;
355 }
356
357 static __initdata struct file *wfile;
358 static __initdata loff_t wfile_pos;
359
do_name(void)360 static int __init do_name(void)
361 {
362 state = SkipIt;
363 next_state = Reset;
364
365 /* name_len > 0 && name_len <= PATH_MAX checked in do_header */
366 if (collected[name_len - 1] != '\0') {
367 pr_err("initramfs name without nulterm: %.*s\n",
368 (int)name_len, collected);
369 error("malformed archive");
370 return 1;
371 }
372
373 if (strcmp(collected, "TRAILER!!!") == 0) {
374 free_hash();
375 return 0;
376 }
377 clean_path(collected, mode);
378 if (S_ISREG(mode)) {
379 int ml = maybe_link();
380 if (ml >= 0) {
381 int openflags = O_WRONLY|O_CREAT|O_LARGEFILE;
382 if (ml != 1)
383 openflags |= O_TRUNC;
384 wfile = filp_open(collected, openflags, mode);
385 if (IS_ERR(wfile))
386 return 0;
387 wfile_pos = 0;
388 io_csum = 0;
389
390 vfs_fchown(wfile, uid, gid);
391 vfs_fchmod(wfile, mode);
392 if (body_len)
393 vfs_truncate(&wfile->f_path, body_len);
394 state = CopyFile;
395 }
396 } else if (S_ISDIR(mode)) {
397 init_mkdir(collected, mode);
398 init_chown(collected, uid, gid, 0);
399 init_chmod(collected, mode);
400 dir_add(collected, name_len, mtime);
401 } else if (S_ISBLK(mode) || S_ISCHR(mode) ||
402 S_ISFIFO(mode) || S_ISSOCK(mode)) {
403 if (maybe_link() == 0) {
404 init_mknod(collected, mode, rdev);
405 init_chown(collected, uid, gid, 0);
406 init_chmod(collected, mode);
407 do_utime(collected, mtime);
408 }
409 }
410 return 0;
411 }
412
do_copy(void)413 static int __init do_copy(void)
414 {
415 if (byte_count >= body_len) {
416 if (xwrite(wfile, victim, body_len, &wfile_pos) != body_len)
417 error("write error");
418
419 do_utime_path(&wfile->f_path, mtime);
420 fput(wfile);
421 if (csum_present && io_csum != hdr_csum)
422 error("bad data checksum");
423 eat(body_len);
424 state = SkipIt;
425 return 0;
426 } else {
427 if (xwrite(wfile, victim, byte_count, &wfile_pos) != byte_count)
428 error("write error");
429 body_len -= byte_count;
430 eat(byte_count);
431 return 1;
432 }
433 }
434
do_symlink(void)435 static int __init do_symlink(void)
436 {
437 if (collected[name_len - 1] != '\0') {
438 pr_err("initramfs symlink without nulterm: %.*s\n",
439 (int)name_len, collected);
440 error("malformed archive");
441 return 1;
442 }
443 collected[N_ALIGN(name_len) + body_len] = '\0';
444 clean_path(collected, 0);
445 init_symlink(collected + N_ALIGN(name_len), collected);
446 init_chown(collected, uid, gid, AT_SYMLINK_NOFOLLOW);
447 do_utime(collected, mtime);
448 state = SkipIt;
449 next_state = Reset;
450 return 0;
451 }
452
453 static __initdata int (*actions[])(void) = {
454 [Start] = do_start,
455 [Collect] = do_collect,
456 [GotHeader] = do_header,
457 [SkipIt] = do_skip,
458 [GotName] = do_name,
459 [CopyFile] = do_copy,
460 [GotSymlink] = do_symlink,
461 [Reset] = do_reset,
462 };
463
write_buffer(char * buf,unsigned long len)464 static long __init write_buffer(char *buf, unsigned long len)
465 {
466 byte_count = len;
467 victim = buf;
468
469 while (!actions[state]())
470 ;
471 return len - byte_count;
472 }
473
flush_buffer(void * bufv,unsigned long len)474 static long __init flush_buffer(void *bufv, unsigned long len)
475 {
476 char *buf = bufv;
477 long written;
478 long origLen = len;
479 if (message)
480 return -1;
481 while ((written = write_buffer(buf, len)) < len && !message) {
482 char c = buf[written];
483 if (c == '0') {
484 buf += written;
485 len -= written;
486 state = Start;
487 } else if (c == 0) {
488 buf += written;
489 len -= written;
490 state = Reset;
491 } else
492 error("junk within compressed archive");
493 }
494 return origLen;
495 }
496
497 static unsigned long my_inptr __initdata; /* index of next byte to be processed in inbuf */
498
499 #include <linux/decompress/generic.h>
500
501 /**
502 * unpack_to_rootfs - decompress and extract an initramfs archive
503 * @buf: input initramfs archive to extract
504 * @len: length of initramfs data to process
505 *
506 * Returns: NULL for success or an error message string
507 *
508 * This symbol shouldn't be used externally. It's available for unit tests.
509 */
unpack_to_rootfs(char * buf,unsigned long len)510 char * __init unpack_to_rootfs(char *buf, unsigned long len)
511 {
512 long written;
513 decompress_fn decompress;
514 const char *compress_name;
515 struct {
516 char header[CPIO_HDRLEN];
517 char symlink[PATH_MAX + N_ALIGN(PATH_MAX) + 1];
518 char name[N_ALIGN(PATH_MAX)];
519 } *bufs = kmalloc(sizeof(*bufs), GFP_KERNEL);
520
521 if (!bufs)
522 panic_show_mem("can't allocate buffers");
523
524 header_buf = bufs->header;
525 symlink_buf = bufs->symlink;
526 name_buf = bufs->name;
527
528 state = Start;
529 this_header = 0;
530 message = NULL;
531 while (!message && len) {
532 loff_t saved_offset = this_header;
533 if (*buf == '0' && !(this_header & 3)) {
534 state = Start;
535 written = write_buffer(buf, len);
536 buf += written;
537 len -= written;
538 continue;
539 }
540 if (!*buf) {
541 buf++;
542 len--;
543 this_header++;
544 continue;
545 }
546 this_header = 0;
547 decompress = decompress_method(buf, len, &compress_name);
548 pr_debug("Detected %s compressed data\n", compress_name);
549 if (decompress) {
550 int res = decompress(buf, len, NULL, flush_buffer, NULL,
551 &my_inptr, error);
552 if (res)
553 error("decompressor failed");
554 } else if (compress_name) {
555 pr_err("compression method %s not configured\n",
556 compress_name);
557 error("decompressor failed");
558 } else
559 error("invalid magic at start of compressed archive");
560 if (state != Reset)
561 error("junk at the end of compressed archive");
562 this_header = saved_offset + my_inptr;
563 buf += my_inptr;
564 len -= my_inptr;
565 }
566 dir_utime();
567 /* free any hardlink state collected without optional TRAILER!!! */
568 free_hash();
569 kfree(bufs);
570 return message;
571 }
572
573 static int __initdata do_retain_initrd;
574
retain_initrd_param(char * str)575 static int __init retain_initrd_param(char *str)
576 {
577 if (*str)
578 return 0;
579 do_retain_initrd = 1;
580 return 1;
581 }
582 __setup("retain_initrd", retain_initrd_param);
583
584 #ifdef CONFIG_ARCH_HAS_KEEPINITRD
keepinitrd_setup(char * __unused)585 static int __init keepinitrd_setup(char *__unused)
586 {
587 do_retain_initrd = 1;
588 return 1;
589 }
590 __setup("keepinitrd", keepinitrd_setup);
591 #endif
592
593 static bool __initdata initramfs_async = true;
initramfs_async_setup(char * str)594 static int __init initramfs_async_setup(char *str)
595 {
596 return kstrtobool(str, &initramfs_async) == 0;
597 }
598 __setup("initramfs_async=", initramfs_async_setup);
599
600 extern char __initramfs_start[];
601 extern unsigned long __initramfs_size;
602 #include <linux/initrd.h>
603 #include <linux/kexec.h>
604
605 static BIN_ATTR(initrd, 0440, sysfs_bin_attr_simple_read, NULL, 0);
606
reserve_initrd_mem(void)607 void __init reserve_initrd_mem(void)
608 {
609 phys_addr_t start;
610 unsigned long size;
611
612 /* Ignore the virtul address computed during device tree parsing */
613 initrd_start = initrd_end = 0;
614
615 if (!phys_initrd_size)
616 return;
617 /*
618 * Round the memory region to page boundaries as per free_initrd_mem()
619 * This allows us to detect whether the pages overlapping the initrd
620 * are in use, but more importantly, reserves the entire set of pages
621 * as we don't want these pages allocated for other purposes.
622 */
623 start = round_down(phys_initrd_start, PAGE_SIZE);
624 size = phys_initrd_size + (phys_initrd_start - start);
625 size = round_up(size, PAGE_SIZE);
626
627 if (!memblock_is_region_memory(start, size)) {
628 pr_err("INITRD: 0x%08llx+0x%08lx is not a memory region",
629 (u64)start, size);
630 goto disable;
631 }
632
633 if (memblock_is_region_reserved(start, size)) {
634 pr_err("INITRD: 0x%08llx+0x%08lx overlaps in-use memory region\n",
635 (u64)start, size);
636 goto disable;
637 }
638
639 memblock_reserve(start, size);
640 /* Now convert initrd to virtual addresses */
641 initrd_start = (unsigned long)__va(phys_initrd_start);
642 initrd_end = initrd_start + phys_initrd_size;
643 initrd_below_start_ok = 1;
644
645 return;
646 disable:
647 pr_cont(" - disabling initrd\n");
648 initrd_start = 0;
649 initrd_end = 0;
650 }
651
free_initrd_mem(unsigned long start,unsigned long end)652 void __weak __init free_initrd_mem(unsigned long start, unsigned long end)
653 {
654 #ifdef CONFIG_ARCH_KEEP_MEMBLOCK
655 unsigned long aligned_start = ALIGN_DOWN(start, PAGE_SIZE);
656 unsigned long aligned_end = ALIGN(end, PAGE_SIZE);
657
658 memblock_free((void *)aligned_start, aligned_end - aligned_start);
659 #endif
660
661 free_reserved_area((void *)start, (void *)end, POISON_FREE_INITMEM,
662 "initrd");
663 }
664
665 #ifdef CONFIG_CRASH_RESERVE
kexec_free_initrd(void)666 static bool __init kexec_free_initrd(void)
667 {
668 unsigned long crashk_start = (unsigned long)__va(crashk_res.start);
669 unsigned long crashk_end = (unsigned long)__va(crashk_res.end);
670
671 /*
672 * If the initrd region is overlapped with crashkernel reserved region,
673 * free only memory that is not part of crashkernel region.
674 */
675 if (initrd_start >= crashk_end || initrd_end <= crashk_start)
676 return false;
677
678 /*
679 * Initialize initrd memory region since the kexec boot does not do.
680 */
681 memset((void *)initrd_start, 0, initrd_end - initrd_start);
682 if (initrd_start < crashk_start)
683 free_initrd_mem(initrd_start, crashk_start);
684 if (initrd_end > crashk_end)
685 free_initrd_mem(crashk_end, initrd_end);
686 return true;
687 }
688 #else
kexec_free_initrd(void)689 static inline bool kexec_free_initrd(void)
690 {
691 return false;
692 }
693 #endif /* CONFIG_KEXEC_CORE */
694
695 #ifdef CONFIG_BLK_DEV_RAM
populate_initrd_image(char * err)696 static void __init populate_initrd_image(char *err)
697 {
698 ssize_t written;
699 struct file *file;
700 loff_t pos = 0;
701
702 printk(KERN_INFO "rootfs image is not initramfs (%s); looks like an initrd\n",
703 err);
704 file = filp_open("/initrd.image", O_WRONLY|O_CREAT|O_LARGEFILE, 0700);
705 if (IS_ERR(file))
706 return;
707
708 written = xwrite(file, (char *)initrd_start, initrd_end - initrd_start,
709 &pos);
710 if (written != initrd_end - initrd_start)
711 pr_err("/initrd.image: incomplete write (%zd != %ld)\n",
712 written, initrd_end - initrd_start);
713 fput(file);
714 }
715 #endif /* CONFIG_BLK_DEV_RAM */
716
do_populate_rootfs(void * unused,async_cookie_t cookie)717 static void __init do_populate_rootfs(void *unused, async_cookie_t cookie)
718 {
719 /* Load the built in initramfs */
720 char *err = unpack_to_rootfs(__initramfs_start, __initramfs_size);
721 if (err)
722 panic_show_mem("%s", err); /* Failed to decompress INTERNAL initramfs */
723
724 if (!initrd_start || IS_ENABLED(CONFIG_INITRAMFS_FORCE))
725 goto done;
726
727 if (IS_ENABLED(CONFIG_BLK_DEV_RAM))
728 printk(KERN_INFO "Trying to unpack rootfs image as initramfs...\n");
729 else
730 printk(KERN_INFO "Unpacking initramfs...\n");
731
732 err = unpack_to_rootfs((char *)initrd_start, initrd_end - initrd_start);
733 if (err) {
734 #ifdef CONFIG_BLK_DEV_RAM
735 populate_initrd_image(err);
736 #else
737 printk(KERN_EMERG "Initramfs unpacking failed: %s\n", err);
738 #endif
739 }
740
741 done:
742 security_initramfs_populated();
743
744 /*
745 * If the initrd region is overlapped with crashkernel reserved region,
746 * free only memory that is not part of crashkernel region.
747 */
748 if (!do_retain_initrd && initrd_start && !kexec_free_initrd()) {
749 free_initrd_mem(initrd_start, initrd_end);
750 } else if (do_retain_initrd && initrd_start) {
751 bin_attr_initrd.size = initrd_end - initrd_start;
752 bin_attr_initrd.private = (void *)initrd_start;
753 if (sysfs_create_bin_file(firmware_kobj, &bin_attr_initrd))
754 pr_err("Failed to create initrd sysfs file");
755 }
756 initrd_start = 0;
757 initrd_end = 0;
758
759 init_flush_fput();
760 }
761
762 static ASYNC_DOMAIN_EXCLUSIVE(initramfs_domain);
763 static async_cookie_t initramfs_cookie;
764
wait_for_initramfs(void)765 void wait_for_initramfs(void)
766 {
767 if (!initramfs_cookie) {
768 /*
769 * Something before rootfs_initcall wants to access
770 * the filesystem/initramfs. Probably a bug. Make a
771 * note, avoid deadlocking the machine, and let the
772 * caller's access fail as it used to.
773 */
774 pr_warn_once("wait_for_initramfs() called before rootfs_initcalls\n");
775 return;
776 }
777 async_synchronize_cookie_domain(initramfs_cookie + 1, &initramfs_domain);
778 }
779 EXPORT_SYMBOL_GPL(wait_for_initramfs);
780
populate_rootfs(void)781 static int __init populate_rootfs(void)
782 {
783 initramfs_cookie = async_schedule_domain(do_populate_rootfs, NULL,
784 &initramfs_domain);
785 usermodehelper_enable();
786 if (!initramfs_async)
787 wait_for_initramfs();
788 return 0;
789 }
790 rootfs_initcall(populate_rootfs);
791