summaryrefslogtreecommitdiff
path: root/init/initramfs.c
blob: e6dbfb767057df7531fc6528899ec854d6bc77a2 (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
438
439
440
441
442
443
444
445
446
447
448
449
450
451
452
453
454
455
456
457
458
459
460
461
462
463
464
465
466
467
468
469
470
471
472
473
474
475
476
477
478
479
480
481
482
483
484
485
486
487
488
489
490
491
492
493
494
495
496
497
498
499
500
501
502
503
504
505
506
507
508
509
510
511
512
513
514
515
516
517
518
519
520
521
522
523
524
525
526
527
528
529
530
531
532
533
534
535
536
537
538
539
540
541
542
543
544
545
546
547
548
549
550
551
552
553
554
555
556
557
558
559
560
561
562
563
564
565
566
567
568
569
570
571
572
573
574
575
576
577
578
579
580
581
582
583
584
585
586
587
588
589
590
591
592
593
594
595
596
597
598
599
600
601
602
603
604
605
606
607
608
609
610
611
612
613
614
615
616
617
618
619
620
621
622
623
624
625
626
627
628
629
630
631
632
633
634
635
636
637
638
639
640
641
642
// SPDX-License-Identifier: GPL-2.0
#include <linux/init.h>
#include <linux/fs.h>
#include <linux/slab.h>
#include <linux/types.h>
#include <linux/fcntl.h>
#include <linux/delay.h>
#include <linux/string.h>
#include <linux/dirent.h>
#include <linux/syscalls.h>
#include <linux/utime.h>
#include <linux/file.h>
#include <linux/memblock.h>
#include <linux/namei.h>
#include <linux/init_syscalls.h>

static ssize_t __init xwrite(struct file *file, const char *p, size_t count,
		loff_t *pos)
{
	ssize_t out = 0;

	/* sys_write only can write MAX_RW_COUNT aka 2G-4K bytes at most */
	while (count) {
		ssize_t rv = kernel_write(file, p, count, pos);

		if (rv < 0) {
			if (rv == -EINTR || rv == -EAGAIN)
				continue;
			return out ? out : rv;
		} else if (rv == 0)
			break;

		p += rv;
		out += rv;
		count -= rv;
	}

	return out;
}

static __initdata char *message;
static void __init error(char *x)
{
	if (!message)
		message = x;
}

/* link hash */

#define N_ALIGN(len) ((((len) + 1) & ~3) + 2)

static __initdata struct hash {
	int ino, minor, major;
	umode_t mode;
	struct hash *next;
	char name[N_ALIGN(PATH_MAX)];
} *head[32];

static inline int hash(int major, int minor, int ino)
{
	unsigned long tmp = ino + minor + (major << 3);
	tmp += tmp >> 5;
	return tmp & 31;
}

static char __init *find_link(int major, int minor, int ino,
			      umode_t mode, char *name)
{
	struct hash **p, *q;
	for (p = head + hash(major, minor, ino); *p; p = &(*p)->next) {
		if ((*p)->ino != ino)
			continue;
		if ((*p)->minor != minor)
			continue;
		if ((*p)->major != major)
			continue;
		if (((*p)->mode ^ mode) & S_IFMT)
			continue;
		return (*p)->name;
	}
	q = kmalloc(sizeof(struct hash), GFP_KERNEL);
	if (!q)
		panic("can't allocate link hash entry");
	q->major = major;
	q->minor = minor;
	q->ino = ino;
	q->mode = mode;
	strcpy(q->name, name);
	q->next = NULL;
	*p = q;
	return NULL;
}

static void __init free_hash(void)
{
	struct hash **p, *q;
	for (p = head; p < head + 32; p++) {
		while (*p) {
			q = *p;
			*p = q->next;
			kfree(q);
		}
	}
}

static long __init do_utime(char *filename, time64_t mtime)
{
	struct timespec64 t[2];

	t[0].tv_sec = mtime;
	t[0].tv_nsec = 0;
	t[1].tv_sec = mtime;
	t[1].tv_nsec = 0;
	return init_utimes(filename, t);
}

static __initdata LIST_HEAD(dir_list);
struct dir_entry {
	struct list_head list;
	char *name;
	time64_t mtime;
};

static void __init dir_add(const char *name, time64_t mtime)
{
	struct dir_entry *de = kmalloc(sizeof(struct dir_entry), GFP_KERNEL);
	if (!de)
		panic("can't allocate dir_entry buffer");
	INIT_LIST_HEAD(&de->list);
	de->name = kstrdup(name, GFP_KERNEL);
	de->mtime = mtime;
	list_add(&de->list, &dir_list);
}

static void __init dir_utime(void)
{
	struct dir_entry *de, *tmp;
	list_for_each_entry_safe(de, tmp, &dir_list, list) {
		list_del(&de->list);
		do_utime(de->name, de->mtime);
		kfree(de->name);
		kfree(de);
	}
}

static __initdata time64_t mtime;

/* cpio header parsing */

static __initdata unsigned long ino, major, minor, nlink;
static __initdata umode_t mode;
static __initdata unsigned long body_len, name_len;
static __initdata uid_t uid;
static __initdata gid_t gid;
static __initdata unsigned rdev;

static void __init parse_header(char *s)
{
	unsigned long parsed[12];
	char buf[9];
	int i;

	buf[8] = '\0';
	for (i = 0, s += 6; i < 12; i++, s += 8) {
		memcpy(buf, s, 8);
		parsed[i] = simple_strtoul(buf, NULL, 16);
	}
	ino = parsed[0];
	mode = parsed[1];
	uid = parsed[2];
	gid = parsed[3];
	nlink = parsed[4];
	mtime = parsed[5]; /* breaks in y2106 */
	body_len = parsed[6];
	major = parsed[7];
	minor = parsed[8];
	rdev = new_encode_dev(MKDEV(parsed[9], parsed[10]));
	name_len = parsed[11];
}

/* FSM */

static __initdata enum state {
	Start,
	Collect,
	GotHeader,
	SkipIt,
	GotName,
	CopyFile,
	GotSymlink,
	Reset
} state, next_state;

static __initdata char *victim;
static unsigned long byte_count __initdata;
static __initdata loff_t this_header, next_header;

static inline void __init eat(unsigned n)
{
	victim += n;
	this_header += n;
	byte_count -= n;
}

static __initdata char *collected;
static long remains __initdata;
static __initdata char *collect;

static void __init read_into(char *buf, unsigned size, enum state next)
{
	if (byte_count >= size) {
		collected = victim;
		eat(size);
		state = next;
	} else {
		collect = collected = buf;
		remains = size;
		next_state = next;
		state = Collect;
	}
}

static __initdata char *header_buf, *symlink_buf, *name_buf;

static int __init do_start(void)
{
	read_into(header_buf, 110, GotHeader);
	return 0;
}

static int __init do_collect(void)
{
	unsigned long n = remains;
	if (byte_count < n)
		n = byte_count;
	memcpy(collect, victim, n);
	eat(n);
	collect += n;
	if ((remains -= n) != 0)
		return 1;
	state = next_state;
	return 0;
}

static int __init do_header(void)
{
	if (memcmp(collected, "070707", 6)==0) {
		error("incorrect cpio method used: use -H newc option");
		return 1;
	}
	if (memcmp(collected, "070701", 6)) {
		error("no cpio magic");
		return 1;
	}
	parse_header(collected);
	next_header = this_header + N_ALIGN(name_len) + body_len;
	next_header = (next_header + 3) & ~3;
	state = SkipIt;
	if (name_len <= 0 || name_len > PATH_MAX)
		return 0;
	if (S_ISLNK(mode)) {
		if (body_len > PATH_MAX)
			return 0;
		collect = collected = symlink_buf;
		remains = N_ALIGN(name_len) + body_len;
		next_state = GotSymlink;
		state = Collect;
		return 0;
	}
	if (S_ISREG(mode) || !body_len)
		read_into(name_buf, N_ALIGN(name_len), GotName);
	return 0;
}

static int __init do_skip(void)
{
	if (this_header + byte_count < next_header) {
		eat(byte_count);
		return 1;
	} else {
		eat(next_header - this_header);
		state = next_state;
		return 0;
	}
}

static int __init do_reset(void)
{
	while (byte_count && *victim == '\0')
		eat(1);
	if (byte_count && (this_header & 3))
		error("broken padding");
	return 1;
}

static void __init clean_path(char *path, umode_t fmode)
{
	struct kstat st;

	if (init_stat(path, &st, AT_SYMLINK_NOFOLLOW) &&
	    (st.mode ^ fmode) & S_IFMT) {
		if (S_ISDIR(st.mode))
			init_rmdir(path);
		else
			init_unlink(path);
	}
}

static int __init maybe_link(void)
{
	if (nlink >= 2) {
		char *old = find_link(major, minor, ino, mode, collected);
		if (old) {
			clean_path(collected, 0);
			return (init_link(old, collected) < 0) ? -1 : 1;
		}
	}
	return 0;
}

static __initdata struct file *wfile;
static __initdata loff_t wfile_pos;

static int __init do_name(void)
{
	state = SkipIt;
	next_state = Reset;
	if (strcmp(collected, "TRAILER!!!") == 0) {
		free_hash();
		return 0;
	}
	clean_path(collected, mode);
	if (S_ISREG(mode)) {
		int ml = maybe_link();
		if (ml >= 0) {
			int openflags = O_WRONLY|O_CREAT;
			if (ml != 1)
				openflags |= O_TRUNC;
			wfile = filp_open(collected, openflags, mode);
			if (IS_ERR(wfile))
				return 0;
			wfile_pos = 0;

			vfs_fchown(wfile, uid, gid);
			vfs_fchmod(wfile, mode);
			if (body_len)
				vfs_truncate(&wfile->f_path, body_len);
			state = CopyFile;
		}
	} else if (S_ISDIR(mode)) {
		init_mkdir(collected, mode);
		init_chown(collected, uid, gid, 0);
		init_chmod(collected, mode);
		dir_add(collected, mtime);
	} else if (S_ISBLK(mode) || S_ISCHR(mode) ||
		   S_ISFIFO(mode) || S_ISSOCK(mode)) {
		if (maybe_link() == 0) {
			init_mknod(collected, mode, rdev);
			init_chown(collected, uid, gid, 0);
			init_chmod(collected, mode);
			do_utime(collected, mtime);
		}
	}
	return 0;
}

static int __init do_copy(void)
{
	if (byte_count >= body_len) {
		struct timespec64 t[2] = { };
		if (xwrite(wfile, victim, body_len, &wfile_pos) != body_len)
			error("write error");

		t[0].tv_sec = mtime;
		t[1].tv_sec = mtime;
		vfs_utimes(&wfile->f_path, t);

		fput(wfile);
		eat(body_len);
		state = SkipIt;
		return 0;
	} else {
		if (xwrite(wfile, victim, byte_count, &wfile_pos) != byte_count)
			error("write error");
		body_len -= byte_count;
		eat(byte_count);
		return 1;
	}
}

static int __init do_symlink(void)
{
	collected[N_ALIGN(name_len) + body_len] = '\0';
	clean_path(collected, 0);
	init_symlink(collected + N_ALIGN(name_len), collected);
	init_chown(collected, uid, gid, AT_SYMLINK_NOFOLLOW);
	do_utime(collected, mtime);
	state = SkipIt;
	next_state = Reset;
	return 0;
}

static __initdata int (*actions[])(void) = {
	[Start]		= do_start,
	[Collect]	= do_collect,
	[GotHeader]	= do_header,
	[SkipIt]	= do_skip,
	[GotName]	= do_name,
	[CopyFile]	= do_copy,
	[GotSymlink]	= do_symlink,
	[Reset]		= do_reset,
};

static long __init write_buffer(char *buf, unsigned long len)
{
	byte_count = len;
	victim = buf;

	while (!actions[state]())
		;
	return len - byte_count;
}

static long __init flush_buffer(void *bufv, unsigned long len)
{
	char *buf = (char *) bufv;
	long written;
	long origLen = len;
	if (message)
		return -1;
	while ((written = write_buffer(buf, len)) < len && !message) {
		char c = buf[written];
		if (c == '0') {
			buf += written;
			len -= written;
			state = Start;
		} else if (c == 0) {
			buf += written;
			len -= written;
			state = Reset;
		} else
			error("junk within compressed archive");
	}
	return origLen;
}

static unsigned long my_inptr; /* index of next byte to be processed in inbuf */

#include <linux/decompress/generic.h>

static char * __init unpack_to_rootfs(char *buf, unsigned long len)
{
	long written;
	decompress_fn decompress;
	const char *compress_name;
	static __initdata char msg_buf[64];

	header_buf = kmalloc(110, GFP_KERNEL);
	symlink_buf = kmalloc(PATH_MAX + N_ALIGN(PATH_MAX) + 1, GFP_KERNEL);
	name_buf = kmalloc(N_ALIGN(PATH_MAX), GFP_KERNEL);

	if (!header_buf || !symlink_buf || !name_buf)
		panic("can't allocate buffers");

	state = Start;
	this_header = 0;
	message = NULL;
	while (!message && len) {
		loff_t saved_offset = this_header;
		if (*buf == '0' && !(this_header & 3)) {
			state = Start;
			written = write_buffer(buf, len);
			buf += written;
			len -= written;
			continue;
		}
		if (!*buf) {
			buf++;
			len--;
			this_header++;
			continue;
		}
		this_header = 0;
		decompress = decompress_method(buf, len, &compress_name);
		pr_debug("Detected %s compressed data\n", compress_name);
		if (decompress) {
			int res = decompress(buf, len, NULL, flush_buffer, NULL,
				   &my_inptr, error);
			if (res)
				error("decompressor failed");
		} else if (compress_name) {
			if (!message) {
				snprintf(msg_buf, sizeof msg_buf,
					 "compression method %s not configured",
					 compress_name);
				message = msg_buf;
			}
		} else
			error("invalid magic at start of compressed archive");
		if (state != Reset)
			error("junk at the end of compressed archive");
		this_header = saved_offset + my_inptr;
		buf += my_inptr;
		len -= my_inptr;
	}
	dir_utime();
	kfree(name_buf);
	kfree(symlink_buf);
	kfree(header_buf);
	return message;
}

static int __initdata do_retain_initrd;

static int __init retain_initrd_param(char *str)
{
	if (*str)
		return 0;
	do_retain_initrd = 1;
	return 1;
}
__setup("retain_initrd", retain_initrd_param);

#ifdef CONFIG_ARCH_HAS_KEEPINITRD
static int __init keepinitrd_setup(char *__unused)
{
	do_retain_initrd = 1;
	return 1;
}
__setup("keepinitrd", keepinitrd_setup);
#endif

extern char __initramfs_start[];
extern unsigned long __initramfs_size;
#include <linux/initrd.h>
#include <linux/kexec.h>

void __weak free_initrd_mem(unsigned long start, unsigned long end)
{
#ifdef CONFIG_ARCH_KEEP_MEMBLOCK
	unsigned long aligned_start = ALIGN_DOWN(start, PAGE_SIZE);
	unsigned long aligned_end = ALIGN(end, PAGE_SIZE);

	memblock_free(__pa(aligned_start), aligned_end - aligned_start);
#endif

	free_reserved_area((void *)start, (void *)end, POISON_FREE_INITMEM,
			"initrd");
}

#ifdef CONFIG_KEXEC_CORE
static bool __init kexec_free_initrd(void)
{
	unsigned long crashk_start = (unsigned long)__va(crashk_res.start);
	unsigned long crashk_end   = (unsigned long)__va(crashk_res.end);

	/*
	 * If the initrd region is overlapped with crashkernel reserved region,
	 * free only memory that is not part of crashkernel region.
	 */
	if (initrd_start >= crashk_end || initrd_end <= crashk_start)
		return false;

	/*
	 * Initialize initrd memory region since the kexec boot does not do.
	 */
	memset((void *)initrd_start, 0, initrd_end - initrd_start);
	if (initrd_start < crashk_start)
		free_initrd_mem(initrd_start, crashk_start);
	if (initrd_end > crashk_end)
		free_initrd_mem(crashk_end, initrd_end);
	return true;
}
#else
static inline bool kexec_free_initrd(void)
{
	return false;
}
#endif /* CONFIG_KEXEC_CORE */

#ifdef CONFIG_BLK_DEV_RAM
static void __init populate_initrd_image(char *err)
{
	ssize_t written;
	struct file *file;
	loff_t pos = 0;

	unpack_to_rootfs(__initramfs_start, __initramfs_size);

	printk(KERN_INFO "rootfs image is not initramfs (%s); looks like an initrd\n",
			err);
	file = filp_open("/initrd.image", O_WRONLY | O_CREAT, 0700);
	if (IS_ERR(file))
		return;

	written = xwrite(file, (char *)initrd_start, initrd_end - initrd_start,
			&pos);
	if (written != initrd_end - initrd_start)
		pr_err("/initrd.image: incomplete write (%zd != %ld)\n",
		       written, initrd_end - initrd_start);
	fput(file);
}
#endif /* CONFIG_BLK_DEV_RAM */

static int __init populate_rootfs(void)
{
	/* Load the built in initramfs */
	char *err = unpack_to_rootfs(__initramfs_start, __initramfs_size);
	if (err)
		panic("%s", err); /* Failed to decompress INTERNAL initramfs */

	if (!initrd_start || IS_ENABLED(CONFIG_INITRAMFS_FORCE))
		goto done;

	if (IS_ENABLED(CONFIG_BLK_DEV_RAM))
		printk(KERN_INFO "Trying to unpack rootfs image as initramfs...\n");
	else
		printk(KERN_INFO "Unpacking initramfs...\n");

	err = unpack_to_rootfs((char *)initrd_start, initrd_end - initrd_start);
	if (err) {
#ifdef CONFIG_BLK_DEV_RAM
		populate_initrd_image(err);
#else
		printk(KERN_EMERG "Initramfs unpacking failed: %s\n", err);
#endif
	}

done:
	/*
	 * If the initrd region is overlapped with crashkernel reserved region,
	 * free only memory that is not part of crashkernel region.
	 */
	if (!do_retain_initrd && initrd_start && !kexec_free_initrd())
		free_initrd_mem(initrd_start, initrd_end);
	initrd_start = 0;
	initrd_end = 0;

	flush_delayed_fput();
	return 0;
}
rootfs_initcall(populate_rootfs);