1 // SPDX-License-Identifier: GPL-2.0
2 #include <linux/init.h>
3 #include <linux/fs.h>
4 #include <linux/slab.h>
5 #include <linux/types.h>
6 #include <linux/fcntl.h>
7 #include <linux/delay.h>
8 #include <linux/string.h>
9 #include <linux/dirent.h>
10 #include <linux/syscalls.h>
11 #include <linux/utime.h>
12 #include <linux/file.h>
13
xwrite(int fd,const char * p,size_t count)14 static ssize_t __init xwrite(int fd, const char *p, size_t count)
15 {
16 ssize_t out = 0;
17
18 /* sys_write only can write MAX_RW_COUNT aka 2G-4K bytes at most */
19 while (count) {
20 ssize_t rv = ksys_write(fd, p, count);
21
22 if (rv < 0) {
23 if (rv == -EINTR || rv == -EAGAIN)
24 continue;
25 return out ? out : rv;
26 } else if (rv == 0)
27 break;
28
29 p += rv;
30 out += rv;
31 count -= rv;
32 }
33
34 return out;
35 }
36
37 static __initdata char *message;
error(char * x)38 static void __init error(char *x)
39 {
40 if (!message)
41 message = x;
42 }
43
44 /* link hash */
45
46 #define N_ALIGN(len) ((((len) + 1) & ~3) + 2)
47
48 static __initdata struct hash {
49 int ino, minor, major;
50 umode_t mode;
51 struct hash *next;
52 char name[N_ALIGN(PATH_MAX)];
53 } *head[32];
54
hash(int major,int minor,int ino)55 static inline int hash(int major, int minor, int ino)
56 {
57 unsigned long tmp = ino + minor + (major << 3);
58 tmp += tmp >> 5;
59 return tmp & 31;
60 }
61
find_link(int major,int minor,int ino,umode_t mode,char * name)62 static char __init *find_link(int major, int minor, int ino,
63 umode_t mode, char *name)
64 {
65 struct hash **p, *q;
66 for (p = head + hash(major, minor, ino); *p; p = &(*p)->next) {
67 if ((*p)->ino != ino)
68 continue;
69 if ((*p)->minor != minor)
70 continue;
71 if ((*p)->major != major)
72 continue;
73 if (((*p)->mode ^ mode) & S_IFMT)
74 continue;
75 return (*p)->name;
76 }
77 q = kmalloc(sizeof(struct hash), GFP_KERNEL);
78 if (!q)
79 panic("can't allocate link hash entry");
80 q->major = major;
81 q->minor = minor;
82 q->ino = ino;
83 q->mode = mode;
84 strcpy(q->name, name);
85 q->next = NULL;
86 *p = q;
87 return NULL;
88 }
89
free_hash(void)90 static void __init free_hash(void)
91 {
92 struct hash **p, *q;
93 for (p = head; p < head + 32; p++) {
94 while (*p) {
95 q = *p;
96 *p = q->next;
97 kfree(q);
98 }
99 }
100 }
101
do_utime(char * filename,time64_t mtime)102 static long __init do_utime(char *filename, time64_t mtime)
103 {
104 struct timespec64 t[2];
105
106 t[0].tv_sec = mtime;
107 t[0].tv_nsec = 0;
108 t[1].tv_sec = mtime;
109 t[1].tv_nsec = 0;
110
111 return do_utimes(AT_FDCWD, filename, t, AT_SYMLINK_NOFOLLOW);
112 }
113
114 static __initdata LIST_HEAD(dir_list);
115 struct dir_entry {
116 struct list_head list;
117 char *name;
118 time64_t mtime;
119 };
120
dir_add(const char * name,time64_t mtime)121 static void __init dir_add(const char *name, time64_t mtime)
122 {
123 struct dir_entry *de = kmalloc(sizeof(struct dir_entry), GFP_KERNEL);
124 if (!de)
125 panic("can't allocate dir_entry buffer");
126 INIT_LIST_HEAD(&de->list);
127 de->name = kstrdup(name, GFP_KERNEL);
128 de->mtime = mtime;
129 list_add(&de->list, &dir_list);
130 }
131
dir_utime(void)132 static void __init dir_utime(void)
133 {
134 struct dir_entry *de, *tmp;
135 list_for_each_entry_safe(de, tmp, &dir_list, list) {
136 list_del(&de->list);
137 do_utime(de->name, de->mtime);
138 kfree(de->name);
139 kfree(de);
140 }
141 }
142
143 static __initdata time64_t mtime;
144
145 /* cpio header parsing */
146
147 static __initdata unsigned long ino, major, minor, nlink;
148 static __initdata umode_t mode;
149 static __initdata unsigned long body_len, name_len;
150 static __initdata uid_t uid;
151 static __initdata gid_t gid;
152 static __initdata unsigned rdev;
153
parse_header(char * s)154 static void __init parse_header(char *s)
155 {
156 unsigned long parsed[12];
157 char buf[9];
158 int i;
159
160 buf[8] = '\0';
161 for (i = 0, s += 6; i < 12; i++, s += 8) {
162 memcpy(buf, s, 8);
163 parsed[i] = simple_strtoul(buf, NULL, 16);
164 }
165 ino = parsed[0];
166 mode = parsed[1];
167 uid = parsed[2];
168 gid = parsed[3];
169 nlink = parsed[4];
170 mtime = parsed[5]; /* breaks in y2106 */
171 body_len = parsed[6];
172 major = parsed[7];
173 minor = parsed[8];
174 rdev = new_encode_dev(MKDEV(parsed[9], parsed[10]));
175 name_len = parsed[11];
176 }
177
178 /* FSM */
179
180 static __initdata enum state {
181 Start,
182 Collect,
183 GotHeader,
184 SkipIt,
185 GotName,
186 CopyFile,
187 GotSymlink,
188 Reset
189 } state, next_state;
190
191 static __initdata char *victim;
192 static unsigned long byte_count __initdata;
193 static __initdata loff_t this_header, next_header;
194
eat(unsigned n)195 static inline void __init eat(unsigned n)
196 {
197 victim += n;
198 this_header += n;
199 byte_count -= n;
200 }
201
202 static __initdata char *vcollected;
203 static __initdata char *collected;
204 static long remains __initdata;
205 static __initdata char *collect;
206
read_into(char * buf,unsigned size,enum state next)207 static void __init read_into(char *buf, unsigned size, enum state next)
208 {
209 if (byte_count >= size) {
210 collected = victim;
211 eat(size);
212 state = next;
213 } else {
214 collect = collected = buf;
215 remains = size;
216 next_state = next;
217 state = Collect;
218 }
219 }
220
221 static __initdata char *header_buf, *symlink_buf, *name_buf;
222
do_start(void)223 static int __init do_start(void)
224 {
225 read_into(header_buf, 110, GotHeader);
226 return 0;
227 }
228
do_collect(void)229 static int __init do_collect(void)
230 {
231 unsigned long n = remains;
232 if (byte_count < n)
233 n = byte_count;
234 memcpy(collect, victim, n);
235 eat(n);
236 collect += n;
237 if ((remains -= n) != 0)
238 return 1;
239 state = next_state;
240 return 0;
241 }
242
do_header(void)243 static int __init do_header(void)
244 {
245 if (memcmp(collected, "070707", 6)==0) {
246 error("incorrect cpio method used: use -H newc option");
247 return 1;
248 }
249 if (memcmp(collected, "070701", 6)) {
250 error("no cpio magic");
251 return 1;
252 }
253 parse_header(collected);
254 next_header = this_header + N_ALIGN(name_len) + body_len;
255 next_header = (next_header + 3) & ~3;
256 state = SkipIt;
257 if (name_len <= 0 || name_len > PATH_MAX)
258 return 0;
259 if (S_ISLNK(mode)) {
260 if (body_len > PATH_MAX)
261 return 0;
262 collect = collected = symlink_buf;
263 remains = N_ALIGN(name_len) + body_len;
264 next_state = GotSymlink;
265 state = Collect;
266 return 0;
267 }
268 if (S_ISREG(mode) || !body_len)
269 read_into(name_buf, N_ALIGN(name_len), GotName);
270 return 0;
271 }
272
do_skip(void)273 static int __init do_skip(void)
274 {
275 if (this_header + byte_count < next_header) {
276 eat(byte_count);
277 return 1;
278 } else {
279 eat(next_header - this_header);
280 state = next_state;
281 return 0;
282 }
283 }
284
do_reset(void)285 static int __init do_reset(void)
286 {
287 while (byte_count && *victim == '\0')
288 eat(1);
289 if (byte_count && (this_header & 3))
290 error("broken padding");
291 return 1;
292 }
293
maybe_link(void)294 static int __init maybe_link(void)
295 {
296 if (nlink >= 2) {
297 char *old = find_link(major, minor, ino, mode, collected);
298 if (old)
299 return (ksys_link(old, collected) < 0) ? -1 : 1;
300 }
301 return 0;
302 }
303
clean_path(char * path,umode_t fmode)304 static void __init clean_path(char *path, umode_t fmode)
305 {
306 struct kstat st;
307
308 if (!vfs_lstat(path, &st) && (st.mode ^ fmode) & S_IFMT) {
309 if (S_ISDIR(st.mode))
310 ksys_rmdir(path);
311 else
312 ksys_unlink(path);
313 }
314 }
315
316 static __initdata int wfd;
317
do_name(void)318 static int __init do_name(void)
319 {
320 state = SkipIt;
321 next_state = Reset;
322 if (strcmp(collected, "TRAILER!!!") == 0) {
323 free_hash();
324 return 0;
325 }
326 clean_path(collected, mode);
327 if (S_ISREG(mode)) {
328 int ml = maybe_link();
329 if (ml >= 0) {
330 int openflags = O_WRONLY|O_CREAT;
331 if (ml != 1)
332 openflags |= O_TRUNC;
333 wfd = ksys_open(collected, openflags, mode);
334
335 if (wfd >= 0) {
336 ksys_fchown(wfd, uid, gid);
337 ksys_fchmod(wfd, mode);
338 if (body_len)
339 ksys_ftruncate(wfd, body_len);
340 vcollected = kstrdup(collected, GFP_KERNEL);
341 state = CopyFile;
342 }
343 }
344 } else if (S_ISDIR(mode)) {
345 ksys_mkdir(collected, mode);
346 ksys_chown(collected, uid, gid);
347 ksys_chmod(collected, mode);
348 dir_add(collected, mtime);
349 } else if (S_ISBLK(mode) || S_ISCHR(mode) ||
350 S_ISFIFO(mode) || S_ISSOCK(mode)) {
351 if (maybe_link() == 0) {
352 ksys_mknod(collected, mode, rdev);
353 ksys_chown(collected, uid, gid);
354 ksys_chmod(collected, mode);
355 do_utime(collected, mtime);
356 }
357 }
358 return 0;
359 }
360
do_copy(void)361 static int __init do_copy(void)
362 {
363 if (byte_count >= body_len) {
364 if (xwrite(wfd, victim, body_len) != body_len)
365 error("write error");
366 ksys_close(wfd);
367 do_utime(vcollected, mtime);
368 kfree(vcollected);
369 eat(body_len);
370 state = SkipIt;
371 return 0;
372 } else {
373 if (xwrite(wfd, victim, byte_count) != byte_count)
374 error("write error");
375 body_len -= byte_count;
376 eat(byte_count);
377 return 1;
378 }
379 }
380
do_symlink(void)381 static int __init do_symlink(void)
382 {
383 collected[N_ALIGN(name_len) + body_len] = '\0';
384 clean_path(collected, 0);
385 ksys_symlink(collected + N_ALIGN(name_len), collected);
386 ksys_lchown(collected, uid, gid);
387 do_utime(collected, mtime);
388 state = SkipIt;
389 next_state = Reset;
390 return 0;
391 }
392
393 static __initdata int (*actions[])(void) = {
394 [Start] = do_start,
395 [Collect] = do_collect,
396 [GotHeader] = do_header,
397 [SkipIt] = do_skip,
398 [GotName] = do_name,
399 [CopyFile] = do_copy,
400 [GotSymlink] = do_symlink,
401 [Reset] = do_reset,
402 };
403
write_buffer(char * buf,unsigned long len)404 static long __init write_buffer(char *buf, unsigned long len)
405 {
406 byte_count = len;
407 victim = buf;
408
409 while (!actions[state]())
410 ;
411 return len - byte_count;
412 }
413
flush_buffer(void * bufv,unsigned long len)414 static long __init flush_buffer(void *bufv, unsigned long len)
415 {
416 char *buf = (char *) bufv;
417 long written;
418 long origLen = len;
419 if (message)
420 return -1;
421 while ((written = write_buffer(buf, len)) < len && !message) {
422 char c = buf[written];
423 if (c == '0') {
424 buf += written;
425 len -= written;
426 state = Start;
427 } else if (c == 0) {
428 buf += written;
429 len -= written;
430 state = Reset;
431 } else
432 error("junk in compressed archive");
433 }
434 return origLen;
435 }
436
437 static unsigned long my_inptr; /* index of next byte to be processed in inbuf */
438
439 #include <linux/decompress/generic.h>
440
unpack_to_rootfs(char * buf,unsigned long len)441 static char * __init unpack_to_rootfs(char *buf, unsigned long len)
442 {
443 long written;
444 decompress_fn decompress;
445 const char *compress_name;
446 static __initdata char msg_buf[64];
447
448 header_buf = kmalloc(110, GFP_KERNEL);
449 symlink_buf = kmalloc(PATH_MAX + N_ALIGN(PATH_MAX) + 1, GFP_KERNEL);
450 name_buf = kmalloc(N_ALIGN(PATH_MAX), GFP_KERNEL);
451
452 if (!header_buf || !symlink_buf || !name_buf)
453 panic("can't allocate buffers");
454
455 state = Start;
456 this_header = 0;
457 message = NULL;
458 while (!message && len) {
459 loff_t saved_offset = this_header;
460 if (*buf == '0' && !(this_header & 3)) {
461 state = Start;
462 written = write_buffer(buf, len);
463 buf += written;
464 len -= written;
465 continue;
466 }
467 if (!*buf) {
468 buf++;
469 len--;
470 this_header++;
471 continue;
472 }
473 this_header = 0;
474 decompress = decompress_method(buf, len, &compress_name);
475 pr_debug("Detected %s compressed data\n", compress_name);
476 if (decompress) {
477 int res = decompress(buf, len, NULL, flush_buffer, NULL,
478 &my_inptr, error);
479 if (res)
480 error("decompressor failed");
481 } else if (compress_name) {
482 if (!message) {
483 snprintf(msg_buf, sizeof msg_buf,
484 "compression method %s not configured",
485 compress_name);
486 message = msg_buf;
487 }
488 } else
489 error("junk in compressed archive");
490 if (state != Reset)
491 error("junk in compressed archive");
492 this_header = saved_offset + my_inptr;
493 buf += my_inptr;
494 len -= my_inptr;
495 }
496 dir_utime();
497 kfree(name_buf);
498 kfree(symlink_buf);
499 kfree(header_buf);
500 return message;
501 }
502
503 static int __initdata do_retain_initrd;
504
retain_initrd_param(char * str)505 static int __init retain_initrd_param(char *str)
506 {
507 if (*str)
508 return 0;
509 do_retain_initrd = 1;
510 return 1;
511 }
512 __setup("retain_initrd", retain_initrd_param);
513
514 extern char __initramfs_start[];
515 extern unsigned long __initramfs_size;
516 #include <linux/initrd.h>
517 #include <linux/kexec.h>
518
free_initrd(void)519 static void __init free_initrd(void)
520 {
521 #ifdef CONFIG_KEXEC_CORE
522 unsigned long crashk_start = (unsigned long)__va(crashk_res.start);
523 unsigned long crashk_end = (unsigned long)__va(crashk_res.end);
524 #endif
525 if (do_retain_initrd)
526 goto skip;
527
528 #ifdef CONFIG_KEXEC_CORE
529 /*
530 * If the initrd region is overlapped with crashkernel reserved region,
531 * free only memory that is not part of crashkernel region.
532 */
533 if (initrd_start < crashk_end && initrd_end > crashk_start) {
534 /*
535 * Initialize initrd memory region since the kexec boot does
536 * not do.
537 */
538 memset((void *)initrd_start, 0, initrd_end - initrd_start);
539 if (initrd_start < crashk_start)
540 free_initrd_mem(initrd_start, crashk_start);
541 if (initrd_end > crashk_end)
542 free_initrd_mem(crashk_end, initrd_end);
543 } else
544 #endif
545 free_initrd_mem(initrd_start, initrd_end);
546 skip:
547 initrd_start = 0;
548 initrd_end = 0;
549 }
550
551 #ifdef CONFIG_BLK_DEV_RAM
552 #define BUF_SIZE 1024
clean_rootfs(void)553 static void __init clean_rootfs(void)
554 {
555 int fd;
556 void *buf;
557 struct linux_dirent64 *dirp;
558 int num;
559
560 fd = ksys_open("/", O_RDONLY, 0);
561 WARN_ON(fd < 0);
562 if (fd < 0)
563 return;
564 buf = kzalloc(BUF_SIZE, GFP_KERNEL);
565 WARN_ON(!buf);
566 if (!buf) {
567 ksys_close(fd);
568 return;
569 }
570
571 dirp = buf;
572 num = ksys_getdents64(fd, dirp, BUF_SIZE);
573 while (num > 0) {
574 while (num > 0) {
575 struct kstat st;
576 int ret;
577
578 ret = vfs_lstat(dirp->d_name, &st);
579 WARN_ON_ONCE(ret);
580 if (!ret) {
581 if (S_ISDIR(st.mode))
582 ksys_rmdir(dirp->d_name);
583 else
584 ksys_unlink(dirp->d_name);
585 }
586
587 num -= dirp->d_reclen;
588 dirp = (void *)dirp + dirp->d_reclen;
589 }
590 dirp = buf;
591 memset(buf, 0, BUF_SIZE);
592 num = ksys_getdents64(fd, dirp, BUF_SIZE);
593 }
594
595 ksys_close(fd);
596 kfree(buf);
597 }
598 #endif
599
populate_rootfs(void)600 static int __init populate_rootfs(void)
601 {
602 /* Load the built in initramfs */
603 char *err = unpack_to_rootfs(__initramfs_start, __initramfs_size);
604 if (err)
605 panic("%s", err); /* Failed to decompress INTERNAL initramfs */
606 /* If available load the bootloader supplied initrd */
607 if (initrd_start && !IS_ENABLED(CONFIG_INITRAMFS_FORCE)) {
608 #ifdef CONFIG_BLK_DEV_RAM
609 int fd;
610 printk(KERN_INFO "Trying to unpack rootfs image as initramfs...\n");
611 err = unpack_to_rootfs((char *)initrd_start,
612 initrd_end - initrd_start);
613 if (!err) {
614 free_initrd();
615 goto done;
616 } else {
617 clean_rootfs();
618 unpack_to_rootfs(__initramfs_start, __initramfs_size);
619 }
620 printk(KERN_INFO "rootfs image is not initramfs (%s)"
621 "; looks like an initrd\n", err);
622 fd = ksys_open("/initrd.image",
623 O_WRONLY|O_CREAT, 0700);
624 if (fd >= 0) {
625 ssize_t written = xwrite(fd, (char *)initrd_start,
626 initrd_end - initrd_start);
627
628 if (written != initrd_end - initrd_start)
629 pr_err("/initrd.image: incomplete write (%zd != %ld)\n",
630 written, initrd_end - initrd_start);
631
632 ksys_close(fd);
633 free_initrd();
634 }
635 done:
636 /* empty statement */;
637 #else
638 printk(KERN_INFO "Unpacking initramfs...\n");
639 err = unpack_to_rootfs((char *)initrd_start,
640 initrd_end - initrd_start);
641 if (err)
642 printk(KERN_EMERG "Initramfs unpacking failed: %s\n", err);
643 free_initrd();
644 #endif
645 }
646 flush_delayed_fput();
647 /*
648 * Try loading default modules from initramfs. This gives
649 * us a chance to load before device_initcalls.
650 */
651 load_default_modules();
652
653 return 0;
654 }
655 rootfs_initcall(populate_rootfs);
656
