xref: /openbmc/linux/init/initramfs.c (revision 95e9fd10) 
1 /*
2  * Many of the syscalls used in this file expect some of the arguments
3  * to be __user pointers not __kernel pointers.  To limit the sparse
4  * noise, turn off sparse checking for this file.
5  */
6 #ifdef __CHECKER__
7 #undef __CHECKER__
8 #warning "Sparse checking disabled for this file"
9 #endif
10 
11 #include <linux/init.h>
12 #include <linux/fs.h>
13 #include <linux/slab.h>
14 #include <linux/types.h>
15 #include <linux/fcntl.h>
16 #include <linux/delay.h>
17 #include <linux/string.h>
18 #include <linux/dirent.h>
19 #include <linux/syscalls.h>
20 #include <linux/utime.h>
21 
22 static __initdata char *message;
23 static void __init error(char *x)
24 {
25 	if (!message)
26 		message = x;
27 }
28 
29 /* link hash */
30 
31 #define N_ALIGN(len) ((((len) + 1) & ~3) + 2)
32 
33 static __initdata struct hash {
34 	int ino, minor, major;
35 	umode_t mode;
36 	struct hash *next;
37 	char name[N_ALIGN(PATH_MAX)];
38 } *head[32];
39 
40 static inline int hash(int major, int minor, int ino)
41 {
42 	unsigned long tmp = ino + minor + (major << 3);
43 	tmp += tmp >> 5;
44 	return tmp & 31;
45 }
46 
47 static char __init *find_link(int major, int minor, int ino,
48 			      umode_t mode, char *name)
49 {
50 	struct hash **p, *q;
51 	for (p = head + hash(major, minor, ino); *p; p = &(*p)->next) {
52 		if ((*p)->ino != ino)
53 			continue;
54 		if ((*p)->minor != minor)
55 			continue;
56 		if ((*p)->major != major)
57 			continue;
58 		if (((*p)->mode ^ mode) & S_IFMT)
59 			continue;
60 		return (*p)->name;
61 	}
62 	q = kmalloc(sizeof(struct hash), GFP_KERNEL);
63 	if (!q)
64 		panic("can't allocate link hash entry");
65 	q->major = major;
66 	q->minor = minor;
67 	q->ino = ino;
68 	q->mode = mode;
69 	strcpy(q->name, name);
70 	q->next = NULL;
71 	*p = q;
72 	return NULL;
73 }
74 
75 static void __init free_hash(void)
76 {
77 	struct hash **p, *q;
78 	for (p = head; p < head + 32; p++) {
79 		while (*p) {
80 			q = *p;
81 			*p = q->next;
82 			kfree(q);
83 		}
84 	}
85 }
86 
87 static long __init do_utime(char *filename, time_t mtime)
88 {
89 	struct timespec t[2];
90 
91 	t[0].tv_sec = mtime;
92 	t[0].tv_nsec = 0;
93 	t[1].tv_sec = mtime;
94 	t[1].tv_nsec = 0;
95 
96 	return do_utimes(AT_FDCWD, filename, t, AT_SYMLINK_NOFOLLOW);
97 }
98 
99 static __initdata LIST_HEAD(dir_list);
100 struct dir_entry {
101 	struct list_head list;
102 	char *name;
103 	time_t mtime;
104 };
105 
106 static void __init dir_add(const char *name, time_t mtime)
107 {
108 	struct dir_entry *de = kmalloc(sizeof(struct dir_entry), GFP_KERNEL);
109 	if (!de)
110 		panic("can't allocate dir_entry buffer");
111 	INIT_LIST_HEAD(&de->list);
112 	de->name = kstrdup(name, GFP_KERNEL);
113 	de->mtime = mtime;
114 	list_add(&de->list, &dir_list);
115 }
116 
117 static void __init dir_utime(void)
118 {
119 	struct dir_entry *de, *tmp;
120 	list_for_each_entry_safe(de, tmp, &dir_list, list) {
121 		list_del(&de->list);
122 		do_utime(de->name, de->mtime);
123 		kfree(de->name);
124 		kfree(de);
125 	}
126 }
127 
128 static __initdata time_t mtime;
129 
130 /* cpio header parsing */
131 
132 static __initdata unsigned long ino, major, minor, nlink;
133 static __initdata umode_t mode;
134 static __initdata unsigned long body_len, name_len;
135 static __initdata uid_t uid;
136 static __initdata gid_t gid;
137 static __initdata unsigned rdev;
138 
139 static void __init parse_header(char *s)
140 {
141 	unsigned long parsed[12];
142 	char buf[9];
143 	int i;
144 
145 	buf[8] = '\0';
146 	for (i = 0, s += 6; i < 12; i++, s += 8) {
147 		memcpy(buf, s, 8);
148 		parsed[i] = simple_strtoul(buf, NULL, 16);
149 	}
150 	ino = parsed[0];
151 	mode = parsed[1];
152 	uid = parsed[2];
153 	gid = parsed[3];
154 	nlink = parsed[4];
155 	mtime = parsed[5];
156 	body_len = parsed[6];
157 	major = parsed[7];
158 	minor = parsed[8];
159 	rdev = new_encode_dev(MKDEV(parsed[9], parsed[10]));
160 	name_len = parsed[11];
161 }
162 
163 /* FSM */
164 
165 static __initdata enum state {
166 	Start,
167 	Collect,
168 	GotHeader,
169 	SkipIt,
170 	GotName,
171 	CopyFile,
172 	GotSymlink,
173 	Reset
174 } state, next_state;
175 
176 static __initdata char *victim;
177 static __initdata unsigned count;
178 static __initdata loff_t this_header, next_header;
179 
180 static inline void __init eat(unsigned n)
181 {
182 	victim += n;
183 	this_header += n;
184 	count -= n;
185 }
186 
187 static __initdata char *vcollected;
188 static __initdata char *collected;
189 static __initdata int remains;
190 static __initdata char *collect;
191 
192 static void __init read_into(char *buf, unsigned size, enum state next)
193 {
194 	if (count >= size) {
195 		collected = victim;
196 		eat(size);
197 		state = next;
198 	} else {
199 		collect = collected = buf;
200 		remains = size;
201 		next_state = next;
202 		state = Collect;
203 	}
204 }
205 
206 static __initdata char *header_buf, *symlink_buf, *name_buf;
207 
208 static int __init do_start(void)
209 {
210 	read_into(header_buf, 110, GotHeader);
211 	return 0;
212 }
213 
214 static int __init do_collect(void)
215 {
216 	unsigned n = remains;
217 	if (count < n)
218 		n = count;
219 	memcpy(collect, victim, n);
220 	eat(n);
221 	collect += n;
222 	if ((remains -= n) != 0)
223 		return 1;
224 	state = next_state;
225 	return 0;
226 }
227 
228 static int __init do_header(void)
229 {
230 	if (memcmp(collected, "070707", 6)==0) {
231 		error("incorrect cpio method used: use -H newc option");
232 		return 1;
233 	}
234 	if (memcmp(collected, "070701", 6)) {
235 		error("no cpio magic");
236 		return 1;
237 	}
238 	parse_header(collected);
239 	next_header = this_header + N_ALIGN(name_len) + body_len;
240 	next_header = (next_header + 3) & ~3;
241 	state = SkipIt;
242 	if (name_len <= 0 || name_len > PATH_MAX)
243 		return 0;
244 	if (S_ISLNK(mode)) {
245 		if (body_len > PATH_MAX)
246 			return 0;
247 		collect = collected = symlink_buf;
248 		remains = N_ALIGN(name_len) + body_len;
249 		next_state = GotSymlink;
250 		state = Collect;
251 		return 0;
252 	}
253 	if (S_ISREG(mode) || !body_len)
254 		read_into(name_buf, N_ALIGN(name_len), GotName);
255 	return 0;
256 }
257 
258 static int __init do_skip(void)
259 {
260 	if (this_header + count < next_header) {
261 		eat(count);
262 		return 1;
263 	} else {
264 		eat(next_header - this_header);
265 		state = next_state;
266 		return 0;
267 	}
268 }
269 
270 static int __init do_reset(void)
271 {
272 	while(count && *victim == '\0')
273 		eat(1);
274 	if (count && (this_header & 3))
275 		error("broken padding");
276 	return 1;
277 }
278 
279 static int __init maybe_link(void)
280 {
281 	if (nlink >= 2) {
282 		char *old = find_link(major, minor, ino, mode, collected);
283 		if (old)
284 			return (sys_link(old, collected) < 0) ? -1 : 1;
285 	}
286 	return 0;
287 }
288 
289 static void __init clean_path(char *path, umode_t mode)
290 {
291 	struct stat st;
292 
293 	if (!sys_newlstat(path, &st) && (st.st_mode^mode) & S_IFMT) {
294 		if (S_ISDIR(st.st_mode))
295 			sys_rmdir(path);
296 		else
297 			sys_unlink(path);
298 	}
299 }
300 
301 static __initdata int wfd;
302 
303 static int __init do_name(void)
304 {
305 	state = SkipIt;
306 	next_state = Reset;
307 	if (strcmp(collected, "TRAILER!!!") == 0) {
308 		free_hash();
309 		return 0;
310 	}
311 	clean_path(collected, mode);
312 	if (S_ISREG(mode)) {
313 		int ml = maybe_link();
314 		if (ml >= 0) {
315 			int openflags = O_WRONLY|O_CREAT;
316 			if (ml != 1)
317 				openflags |= O_TRUNC;
318 			wfd = sys_open(collected, openflags, mode);
319 
320 			if (wfd >= 0) {
321 				sys_fchown(wfd, uid, gid);
322 				sys_fchmod(wfd, mode);
323 				if (body_len)
324 					sys_ftruncate(wfd, body_len);
325 				vcollected = kstrdup(collected, GFP_KERNEL);
326 				state = CopyFile;
327 			}
328 		}
329 	} else if (S_ISDIR(mode)) {
330 		sys_mkdir(collected, mode);
331 		sys_chown(collected, uid, gid);
332 		sys_chmod(collected, mode);
333 		dir_add(collected, mtime);
334 	} else if (S_ISBLK(mode) || S_ISCHR(mode) ||
335 		   S_ISFIFO(mode) || S_ISSOCK(mode)) {
336 		if (maybe_link() == 0) {
337 			sys_mknod(collected, mode, rdev);
338 			sys_chown(collected, uid, gid);
339 			sys_chmod(collected, mode);
340 			do_utime(collected, mtime);
341 		}
342 	}
343 	return 0;
344 }
345 
346 static int __init do_copy(void)
347 {
348 	if (count >= body_len) {
349 		sys_write(wfd, victim, body_len);
350 		sys_close(wfd);
351 		do_utime(vcollected, mtime);
352 		kfree(vcollected);
353 		eat(body_len);
354 		state = SkipIt;
355 		return 0;
356 	} else {
357 		sys_write(wfd, victim, count);
358 		body_len -= count;
359 		eat(count);
360 		return 1;
361 	}
362 }
363 
364 static int __init do_symlink(void)
365 {
366 	collected[N_ALIGN(name_len) + body_len] = '\0';
367 	clean_path(collected, 0);
368 	sys_symlink(collected + N_ALIGN(name_len), collected);
369 	sys_lchown(collected, uid, gid);
370 	do_utime(collected, mtime);
371 	state = SkipIt;
372 	next_state = Reset;
373 	return 0;
374 }
375 
376 static __initdata int (*actions[])(void) = {
377 	[Start]		= do_start,
378 	[Collect]	= do_collect,
379 	[GotHeader]	= do_header,
380 	[SkipIt]	= do_skip,
381 	[GotName]	= do_name,
382 	[CopyFile]	= do_copy,
383 	[GotSymlink]	= do_symlink,
384 	[Reset]		= do_reset,
385 };
386 
387 static int __init write_buffer(char *buf, unsigned len)
388 {
389 	count = len;
390 	victim = buf;
391 
392 	while (!actions[state]())
393 		;
394 	return len - count;
395 }
396 
397 static int __init flush_buffer(void *bufv, unsigned len)
398 {
399 	char *buf = (char *) bufv;
400 	int written;
401 	int origLen = len;
402 	if (message)
403 		return -1;
404 	while ((written = write_buffer(buf, len)) < len && !message) {
405 		char c = buf[written];
406 		if (c == '0') {
407 			buf += written;
408 			len -= written;
409 			state = Start;
410 		} else if (c == 0) {
411 			buf += written;
412 			len -= written;
413 			state = Reset;
414 		} else
415 			error("junk in compressed archive");
416 	}
417 	return origLen;
418 }
419 
420 static unsigned my_inptr;   /* index of next byte to be processed in inbuf */
421 
422 #include <linux/decompress/generic.h>
423 
424 static char * __init unpack_to_rootfs(char *buf, unsigned len)
425 {
426 	int written, res;
427 	decompress_fn decompress;
428 	const char *compress_name;
429 	static __initdata char msg_buf[64];
430 
431 	header_buf = kmalloc(110, GFP_KERNEL);
432 	symlink_buf = kmalloc(PATH_MAX + N_ALIGN(PATH_MAX) + 1, GFP_KERNEL);
433 	name_buf = kmalloc(N_ALIGN(PATH_MAX), GFP_KERNEL);
434 
435 	if (!header_buf || !symlink_buf || !name_buf)
436 		panic("can't allocate buffers");
437 
438 	state = Start;
439 	this_header = 0;
440 	message = NULL;
441 	while (!message && len) {
442 		loff_t saved_offset = this_header;
443 		if (*buf == '0' && !(this_header & 3)) {
444 			state = Start;
445 			written = write_buffer(buf, len);
446 			buf += written;
447 			len -= written;
448 			continue;
449 		}
450 		if (!*buf) {
451 			buf++;
452 			len--;
453 			this_header++;
454 			continue;
455 		}
456 		this_header = 0;
457 		decompress = decompress_method(buf, len, &compress_name);
458 		if (decompress) {
459 			res = decompress(buf, len, NULL, flush_buffer, NULL,
460 				   &my_inptr, error);
461 			if (res)
462 				error("decompressor failed");
463 		} else if (compress_name) {
464 			if (!message) {
465 				snprintf(msg_buf, sizeof msg_buf,
466 					 "compression method %s not configured",
467 					 compress_name);
468 				message = msg_buf;
469 			}
470 		} else
471 			error("junk in compressed archive");
472 		if (state != Reset)
473 			error("junk in compressed archive");
474 		this_header = saved_offset + my_inptr;
475 		buf += my_inptr;
476 		len -= my_inptr;
477 	}
478 	dir_utime();
479 	kfree(name_buf);
480 	kfree(symlink_buf);
481 	kfree(header_buf);
482 	return message;
483 }
484 
485 static int __initdata do_retain_initrd;
486 
487 static int __init retain_initrd_param(char *str)
488 {
489 	if (*str)
490 		return 0;
491 	do_retain_initrd = 1;
492 	return 1;
493 }
494 __setup("retain_initrd", retain_initrd_param);
495 
496 extern char __initramfs_start[];
497 extern unsigned long __initramfs_size;
498 #include <linux/initrd.h>
499 #include <linux/kexec.h>
500 
501 static void __init free_initrd(void)
502 {
503 #ifdef CONFIG_KEXEC
504 	unsigned long crashk_start = (unsigned long)__va(crashk_res.start);
505 	unsigned long crashk_end   = (unsigned long)__va(crashk_res.end);
506 #endif
507 	if (do_retain_initrd)
508 		goto skip;
509 
510 #ifdef CONFIG_KEXEC
511 	/*
512 	 * If the initrd region is overlapped with crashkernel reserved region,
513 	 * free only memory that is not part of crashkernel region.
514 	 */
515 	if (initrd_start < crashk_end && initrd_end > crashk_start) {
516 		/*
517 		 * Initialize initrd memory region since the kexec boot does
518 		 * not do.
519 		 */
520 		memset((void *)initrd_start, 0, initrd_end - initrd_start);
521 		if (initrd_start < crashk_start)
522 			free_initrd_mem(initrd_start, crashk_start);
523 		if (initrd_end > crashk_end)
524 			free_initrd_mem(crashk_end, initrd_end);
525 	} else
526 #endif
527 		free_initrd_mem(initrd_start, initrd_end);
528 skip:
529 	initrd_start = 0;
530 	initrd_end = 0;
531 }
532 
533 #ifdef CONFIG_BLK_DEV_RAM
534 #define BUF_SIZE 1024
535 static void __init clean_rootfs(void)
536 {
537 	int fd;
538 	void *buf;
539 	struct linux_dirent64 *dirp;
540 	int num;
541 
542 	fd = sys_open("/", O_RDONLY, 0);
543 	WARN_ON(fd < 0);
544 	if (fd < 0)
545 		return;
546 	buf = kzalloc(BUF_SIZE, GFP_KERNEL);
547 	WARN_ON(!buf);
548 	if (!buf) {
549 		sys_close(fd);
550 		return;
551 	}
552 
553 	dirp = buf;
554 	num = sys_getdents64(fd, dirp, BUF_SIZE);
555 	while (num > 0) {
556 		while (num > 0) {
557 			struct stat st;
558 			int ret;
559 
560 			ret = sys_newlstat(dirp->d_name, &st);
561 			WARN_ON_ONCE(ret);
562 			if (!ret) {
563 				if (S_ISDIR(st.st_mode))
564 					sys_rmdir(dirp->d_name);
565 				else
566 					sys_unlink(dirp->d_name);
567 			}
568 
569 			num -= dirp->d_reclen;
570 			dirp = (void *)dirp + dirp->d_reclen;
571 		}
572 		dirp = buf;
573 		memset(buf, 0, BUF_SIZE);
574 		num = sys_getdents64(fd, dirp, BUF_SIZE);
575 	}
576 
577 	sys_close(fd);
578 	kfree(buf);
579 }
580 #endif
581 
582 static int __init populate_rootfs(void)
583 {
584 	char *err = unpack_to_rootfs(__initramfs_start, __initramfs_size);
585 	if (err)
586 		panic(err);	/* Failed to decompress INTERNAL initramfs */
587 	if (initrd_start) {
588 #ifdef CONFIG_BLK_DEV_RAM
589 		int fd;
590 		printk(KERN_INFO "Trying to unpack rootfs image as initramfs...\n");
591 		err = unpack_to_rootfs((char *)initrd_start,
592 			initrd_end - initrd_start);
593 		if (!err) {
594 			free_initrd();
595 			return 0;
596 		} else {
597 			clean_rootfs();
598 			unpack_to_rootfs(__initramfs_start, __initramfs_size);
599 		}
600 		printk(KERN_INFO "rootfs image is not initramfs (%s)"
601 				"; looks like an initrd\n", err);
602 		fd = sys_open("/initrd.image",
603 			      O_WRONLY|O_CREAT, 0700);
604 		if (fd >= 0) {
605 			sys_write(fd, (char *)initrd_start,
606 					initrd_end - initrd_start);
607 			sys_close(fd);
608 			free_initrd();
609 		}
610 #else
611 		printk(KERN_INFO "Unpacking initramfs...\n");
612 		err = unpack_to_rootfs((char *)initrd_start,
613 			initrd_end - initrd_start);
614 		if (err)
615 			printk(KERN_EMERG "Initramfs unpacking failed: %s\n", err);
616 		free_initrd();
617 #endif
618 	}
619 	return 0;
620 }
621 rootfs_initcall(populate_rootfs);
622