xref: /openbmc/linux/init/initramfs.c (revision 4800cd83)
1 #include <linux/init.h>
2 #include <linux/fs.h>
3 #include <linux/slab.h>
4 #include <linux/types.h>
5 #include <linux/fcntl.h>
6 #include <linux/delay.h>
7 #include <linux/string.h>
8 #include <linux/dirent.h>
9 #include <linux/syscalls.h>
10 #include <linux/utime.h>
11 
12 static __initdata char *message;
13 static void __init error(char *x)
14 {
15 	if (!message)
16 		message = x;
17 }
18 
19 /* link hash */
20 
21 #define N_ALIGN(len) ((((len) + 1) & ~3) + 2)
22 
23 static __initdata struct hash {
24 	int ino, minor, major;
25 	mode_t mode;
26 	struct hash *next;
27 	char name[N_ALIGN(PATH_MAX)];
28 } *head[32];
29 
30 static inline int hash(int major, int minor, int ino)
31 {
32 	unsigned long tmp = ino + minor + (major << 3);
33 	tmp += tmp >> 5;
34 	return tmp & 31;
35 }
36 
37 static char __init *find_link(int major, int minor, int ino,
38 			      mode_t mode, char *name)
39 {
40 	struct hash **p, *q;
41 	for (p = head + hash(major, minor, ino); *p; p = &(*p)->next) {
42 		if ((*p)->ino != ino)
43 			continue;
44 		if ((*p)->minor != minor)
45 			continue;
46 		if ((*p)->major != major)
47 			continue;
48 		if (((*p)->mode ^ mode) & S_IFMT)
49 			continue;
50 		return (*p)->name;
51 	}
52 	q = kmalloc(sizeof(struct hash), GFP_KERNEL);
53 	if (!q)
54 		panic("can't allocate link hash entry");
55 	q->major = major;
56 	q->minor = minor;
57 	q->ino = ino;
58 	q->mode = mode;
59 	strcpy(q->name, name);
60 	q->next = NULL;
61 	*p = q;
62 	return NULL;
63 }
64 
65 static void __init free_hash(void)
66 {
67 	struct hash **p, *q;
68 	for (p = head; p < head + 32; p++) {
69 		while (*p) {
70 			q = *p;
71 			*p = q->next;
72 			kfree(q);
73 		}
74 	}
75 }
76 
77 static long __init do_utime(char __user *filename, time_t mtime)
78 {
79 	struct timespec t[2];
80 
81 	t[0].tv_sec = mtime;
82 	t[0].tv_nsec = 0;
83 	t[1].tv_sec = mtime;
84 	t[1].tv_nsec = 0;
85 
86 	return do_utimes(AT_FDCWD, filename, t, AT_SYMLINK_NOFOLLOW);
87 }
88 
89 static __initdata LIST_HEAD(dir_list);
90 struct dir_entry {
91 	struct list_head list;
92 	char *name;
93 	time_t mtime;
94 };
95 
96 static void __init dir_add(const char *name, time_t mtime)
97 {
98 	struct dir_entry *de = kmalloc(sizeof(struct dir_entry), GFP_KERNEL);
99 	if (!de)
100 		panic("can't allocate dir_entry buffer");
101 	INIT_LIST_HEAD(&de->list);
102 	de->name = kstrdup(name, GFP_KERNEL);
103 	de->mtime = mtime;
104 	list_add(&de->list, &dir_list);
105 }
106 
107 static void __init dir_utime(void)
108 {
109 	struct dir_entry *de, *tmp;
110 	list_for_each_entry_safe(de, tmp, &dir_list, list) {
111 		list_del(&de->list);
112 		do_utime(de->name, de->mtime);
113 		kfree(de->name);
114 		kfree(de);
115 	}
116 }
117 
118 static __initdata time_t mtime;
119 
120 /* cpio header parsing */
121 
122 static __initdata unsigned long ino, major, minor, nlink;
123 static __initdata mode_t mode;
124 static __initdata unsigned long body_len, name_len;
125 static __initdata uid_t uid;
126 static __initdata gid_t gid;
127 static __initdata unsigned rdev;
128 
129 static void __init parse_header(char *s)
130 {
131 	unsigned long parsed[12];
132 	char buf[9];
133 	int i;
134 
135 	buf[8] = '\0';
136 	for (i = 0, s += 6; i < 12; i++, s += 8) {
137 		memcpy(buf, s, 8);
138 		parsed[i] = simple_strtoul(buf, NULL, 16);
139 	}
140 	ino = parsed[0];
141 	mode = parsed[1];
142 	uid = parsed[2];
143 	gid = parsed[3];
144 	nlink = parsed[4];
145 	mtime = parsed[5];
146 	body_len = parsed[6];
147 	major = parsed[7];
148 	minor = parsed[8];
149 	rdev = new_encode_dev(MKDEV(parsed[9], parsed[10]));
150 	name_len = parsed[11];
151 }
152 
153 /* FSM */
154 
155 static __initdata enum state {
156 	Start,
157 	Collect,
158 	GotHeader,
159 	SkipIt,
160 	GotName,
161 	CopyFile,
162 	GotSymlink,
163 	Reset
164 } state, next_state;
165 
166 static __initdata char *victim;
167 static __initdata unsigned count;
168 static __initdata loff_t this_header, next_header;
169 
170 static inline void __init eat(unsigned n)
171 {
172 	victim += n;
173 	this_header += n;
174 	count -= n;
175 }
176 
177 static __initdata char *vcollected;
178 static __initdata char *collected;
179 static __initdata int remains;
180 static __initdata char *collect;
181 
182 static void __init read_into(char *buf, unsigned size, enum state next)
183 {
184 	if (count >= size) {
185 		collected = victim;
186 		eat(size);
187 		state = next;
188 	} else {
189 		collect = collected = buf;
190 		remains = size;
191 		next_state = next;
192 		state = Collect;
193 	}
194 }
195 
196 static __initdata char *header_buf, *symlink_buf, *name_buf;
197 
198 static int __init do_start(void)
199 {
200 	read_into(header_buf, 110, GotHeader);
201 	return 0;
202 }
203 
204 static int __init do_collect(void)
205 {
206 	unsigned n = remains;
207 	if (count < n)
208 		n = count;
209 	memcpy(collect, victim, n);
210 	eat(n);
211 	collect += n;
212 	if ((remains -= n) != 0)
213 		return 1;
214 	state = next_state;
215 	return 0;
216 }
217 
218 static int __init do_header(void)
219 {
220 	if (memcmp(collected, "070707", 6)==0) {
221 		error("incorrect cpio method used: use -H newc option");
222 		return 1;
223 	}
224 	if (memcmp(collected, "070701", 6)) {
225 		error("no cpio magic");
226 		return 1;
227 	}
228 	parse_header(collected);
229 	next_header = this_header + N_ALIGN(name_len) + body_len;
230 	next_header = (next_header + 3) & ~3;
231 	state = SkipIt;
232 	if (name_len <= 0 || name_len > PATH_MAX)
233 		return 0;
234 	if (S_ISLNK(mode)) {
235 		if (body_len > PATH_MAX)
236 			return 0;
237 		collect = collected = symlink_buf;
238 		remains = N_ALIGN(name_len) + body_len;
239 		next_state = GotSymlink;
240 		state = Collect;
241 		return 0;
242 	}
243 	if (S_ISREG(mode) || !body_len)
244 		read_into(name_buf, N_ALIGN(name_len), GotName);
245 	return 0;
246 }
247 
248 static int __init do_skip(void)
249 {
250 	if (this_header + count < next_header) {
251 		eat(count);
252 		return 1;
253 	} else {
254 		eat(next_header - this_header);
255 		state = next_state;
256 		return 0;
257 	}
258 }
259 
260 static int __init do_reset(void)
261 {
262 	while(count && *victim == '\0')
263 		eat(1);
264 	if (count && (this_header & 3))
265 		error("broken padding");
266 	return 1;
267 }
268 
269 static int __init maybe_link(void)
270 {
271 	if (nlink >= 2) {
272 		char *old = find_link(major, minor, ino, mode, collected);
273 		if (old)
274 			return (sys_link(old, collected) < 0) ? -1 : 1;
275 	}
276 	return 0;
277 }
278 
279 static void __init clean_path(char *path, mode_t mode)
280 {
281 	struct stat st;
282 
283 	if (!sys_newlstat(path, &st) && (st.st_mode^mode) & S_IFMT) {
284 		if (S_ISDIR(st.st_mode))
285 			sys_rmdir(path);
286 		else
287 			sys_unlink(path);
288 	}
289 }
290 
291 static __initdata int wfd;
292 
293 static int __init do_name(void)
294 {
295 	state = SkipIt;
296 	next_state = Reset;
297 	if (strcmp(collected, "TRAILER!!!") == 0) {
298 		free_hash();
299 		return 0;
300 	}
301 	clean_path(collected, mode);
302 	if (S_ISREG(mode)) {
303 		int ml = maybe_link();
304 		if (ml >= 0) {
305 			int openflags = O_WRONLY|O_CREAT;
306 			if (ml != 1)
307 				openflags |= O_TRUNC;
308 			wfd = sys_open(collected, openflags, mode);
309 
310 			if (wfd >= 0) {
311 				sys_fchown(wfd, uid, gid);
312 				sys_fchmod(wfd, mode);
313 				if (body_len)
314 					sys_ftruncate(wfd, body_len);
315 				vcollected = kstrdup(collected, GFP_KERNEL);
316 				state = CopyFile;
317 			}
318 		}
319 	} else if (S_ISDIR(mode)) {
320 		sys_mkdir(collected, mode);
321 		sys_chown(collected, uid, gid);
322 		sys_chmod(collected, mode);
323 		dir_add(collected, mtime);
324 	} else if (S_ISBLK(mode) || S_ISCHR(mode) ||
325 		   S_ISFIFO(mode) || S_ISSOCK(mode)) {
326 		if (maybe_link() == 0) {
327 			sys_mknod(collected, mode, rdev);
328 			sys_chown(collected, uid, gid);
329 			sys_chmod(collected, mode);
330 			do_utime(collected, mtime);
331 		}
332 	}
333 	return 0;
334 }
335 
336 static int __init do_copy(void)
337 {
338 	if (count >= body_len) {
339 		sys_write(wfd, victim, body_len);
340 		sys_close(wfd);
341 		do_utime(vcollected, mtime);
342 		kfree(vcollected);
343 		eat(body_len);
344 		state = SkipIt;
345 		return 0;
346 	} else {
347 		sys_write(wfd, victim, count);
348 		body_len -= count;
349 		eat(count);
350 		return 1;
351 	}
352 }
353 
354 static int __init do_symlink(void)
355 {
356 	collected[N_ALIGN(name_len) + body_len] = '\0';
357 	clean_path(collected, 0);
358 	sys_symlink(collected + N_ALIGN(name_len), collected);
359 	sys_lchown(collected, uid, gid);
360 	do_utime(collected, mtime);
361 	state = SkipIt;
362 	next_state = Reset;
363 	return 0;
364 }
365 
366 static __initdata int (*actions[])(void) = {
367 	[Start]		= do_start,
368 	[Collect]	= do_collect,
369 	[GotHeader]	= do_header,
370 	[SkipIt]	= do_skip,
371 	[GotName]	= do_name,
372 	[CopyFile]	= do_copy,
373 	[GotSymlink]	= do_symlink,
374 	[Reset]		= do_reset,
375 };
376 
377 static int __init write_buffer(char *buf, unsigned len)
378 {
379 	count = len;
380 	victim = buf;
381 
382 	while (!actions[state]())
383 		;
384 	return len - count;
385 }
386 
387 static int __init flush_buffer(void *bufv, unsigned len)
388 {
389 	char *buf = (char *) bufv;
390 	int written;
391 	int origLen = len;
392 	if (message)
393 		return -1;
394 	while ((written = write_buffer(buf, len)) < len && !message) {
395 		char c = buf[written];
396 		if (c == '0') {
397 			buf += written;
398 			len -= written;
399 			state = Start;
400 		} else if (c == 0) {
401 			buf += written;
402 			len -= written;
403 			state = Reset;
404 		} else
405 			error("junk in compressed archive");
406 	}
407 	return origLen;
408 }
409 
410 static unsigned my_inptr;   /* index of next byte to be processed in inbuf */
411 
412 #include <linux/decompress/generic.h>
413 
414 static char * __init unpack_to_rootfs(char *buf, unsigned len)
415 {
416 	int written, res;
417 	decompress_fn decompress;
418 	const char *compress_name;
419 	static __initdata char msg_buf[64];
420 
421 	header_buf = kmalloc(110, GFP_KERNEL);
422 	symlink_buf = kmalloc(PATH_MAX + N_ALIGN(PATH_MAX) + 1, GFP_KERNEL);
423 	name_buf = kmalloc(N_ALIGN(PATH_MAX), GFP_KERNEL);
424 
425 	if (!header_buf || !symlink_buf || !name_buf)
426 		panic("can't allocate buffers");
427 
428 	state = Start;
429 	this_header = 0;
430 	message = NULL;
431 	while (!message && len) {
432 		loff_t saved_offset = this_header;
433 		if (*buf == '0' && !(this_header & 3)) {
434 			state = Start;
435 			written = write_buffer(buf, len);
436 			buf += written;
437 			len -= written;
438 			continue;
439 		}
440 		if (!*buf) {
441 			buf++;
442 			len--;
443 			this_header++;
444 			continue;
445 		}
446 		this_header = 0;
447 		decompress = decompress_method(buf, len, &compress_name);
448 		if (decompress) {
449 			res = decompress(buf, len, NULL, flush_buffer, NULL,
450 				   &my_inptr, error);
451 			if (res)
452 				error("decompressor failed");
453 		} else if (compress_name) {
454 			if (!message) {
455 				snprintf(msg_buf, sizeof msg_buf,
456 					 "compression method %s not configured",
457 					 compress_name);
458 				message = msg_buf;
459 			}
460 		} else
461 			error("junk in compressed archive");
462 		if (state != Reset)
463 			error("junk in compressed archive");
464 		this_header = saved_offset + my_inptr;
465 		buf += my_inptr;
466 		len -= my_inptr;
467 	}
468 	dir_utime();
469 	kfree(name_buf);
470 	kfree(symlink_buf);
471 	kfree(header_buf);
472 	return message;
473 }
474 
475 static int __initdata do_retain_initrd;
476 
477 static int __init retain_initrd_param(char *str)
478 {
479 	if (*str)
480 		return 0;
481 	do_retain_initrd = 1;
482 	return 1;
483 }
484 __setup("retain_initrd", retain_initrd_param);
485 
486 extern char __initramfs_start[];
487 extern unsigned long __initramfs_size;
488 #include <linux/initrd.h>
489 #include <linux/kexec.h>
490 
491 static void __init free_initrd(void)
492 {
493 #ifdef CONFIG_KEXEC
494 	unsigned long crashk_start = (unsigned long)__va(crashk_res.start);
495 	unsigned long crashk_end   = (unsigned long)__va(crashk_res.end);
496 #endif
497 	if (do_retain_initrd)
498 		goto skip;
499 
500 #ifdef CONFIG_KEXEC
501 	/*
502 	 * If the initrd region is overlapped with crashkernel reserved region,
503 	 * free only memory that is not part of crashkernel region.
504 	 */
505 	if (initrd_start < crashk_end && initrd_end > crashk_start) {
506 		/*
507 		 * Initialize initrd memory region since the kexec boot does
508 		 * not do.
509 		 */
510 		memset((void *)initrd_start, 0, initrd_end - initrd_start);
511 		if (initrd_start < crashk_start)
512 			free_initrd_mem(initrd_start, crashk_start);
513 		if (initrd_end > crashk_end)
514 			free_initrd_mem(crashk_end, initrd_end);
515 	} else
516 #endif
517 		free_initrd_mem(initrd_start, initrd_end);
518 skip:
519 	initrd_start = 0;
520 	initrd_end = 0;
521 }
522 
523 #ifdef CONFIG_BLK_DEV_RAM
524 #define BUF_SIZE 1024
525 static void __init clean_rootfs(void)
526 {
527 	int fd;
528 	void *buf;
529 	struct linux_dirent64 *dirp;
530 	int num;
531 
532 	fd = sys_open((const char __user __force *) "/", O_RDONLY, 0);
533 	WARN_ON(fd < 0);
534 	if (fd < 0)
535 		return;
536 	buf = kzalloc(BUF_SIZE, GFP_KERNEL);
537 	WARN_ON(!buf);
538 	if (!buf) {
539 		sys_close(fd);
540 		return;
541 	}
542 
543 	dirp = buf;
544 	num = sys_getdents64(fd, dirp, BUF_SIZE);
545 	while (num > 0) {
546 		while (num > 0) {
547 			struct stat st;
548 			int ret;
549 
550 			ret = sys_newlstat(dirp->d_name, &st);
551 			WARN_ON_ONCE(ret);
552 			if (!ret) {
553 				if (S_ISDIR(st.st_mode))
554 					sys_rmdir(dirp->d_name);
555 				else
556 					sys_unlink(dirp->d_name);
557 			}
558 
559 			num -= dirp->d_reclen;
560 			dirp = (void *)dirp + dirp->d_reclen;
561 		}
562 		dirp = buf;
563 		memset(buf, 0, BUF_SIZE);
564 		num = sys_getdents64(fd, dirp, BUF_SIZE);
565 	}
566 
567 	sys_close(fd);
568 	kfree(buf);
569 }
570 #endif
571 
572 static int __init populate_rootfs(void)
573 {
574 	char *err = unpack_to_rootfs(__initramfs_start, __initramfs_size);
575 	if (err)
576 		panic(err);	/* Failed to decompress INTERNAL initramfs */
577 	if (initrd_start) {
578 #ifdef CONFIG_BLK_DEV_RAM
579 		int fd;
580 		printk(KERN_INFO "Trying to unpack rootfs image as initramfs...\n");
581 		err = unpack_to_rootfs((char *)initrd_start,
582 			initrd_end - initrd_start);
583 		if (!err) {
584 			free_initrd();
585 			return 0;
586 		} else {
587 			clean_rootfs();
588 			unpack_to_rootfs(__initramfs_start, __initramfs_size);
589 		}
590 		printk(KERN_INFO "rootfs image is not initramfs (%s)"
591 				"; looks like an initrd\n", err);
592 		fd = sys_open((const char __user __force *) "/initrd.image",
593 			      O_WRONLY|O_CREAT, 0700);
594 		if (fd >= 0) {
595 			sys_write(fd, (char *)initrd_start,
596 					initrd_end - initrd_start);
597 			sys_close(fd);
598 			free_initrd();
599 		}
600 #else
601 		printk(KERN_INFO "Unpacking initramfs...\n");
602 		err = unpack_to_rootfs((char *)initrd_start,
603 			initrd_end - initrd_start);
604 		if (err)
605 			printk(KERN_EMERG "Initramfs unpacking failed: %s\n", err);
606 		free_initrd();
607 #endif
608 	}
609 	return 0;
610 }
611 rootfs_initcall(populate_rootfs);
612