summaryrefslogtreecommitdiffstats
path: root/package/system/mtd/src/wrgg.c
blob: c62f9f5507363508954d4ad6a84e256f2c2d4cf4 (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
/*
 * wrgg.c
 *
 * Copyright (C) 2005 Mike Baker
 * Copyright (C) 2008 Felix Fietkau <nbd@nbd.name>
 * Copyright (C) 2011-2012 Gabor Juhos <juhosg@openwrt.org>
 * Copyright (C) 2016 Stijn Tintel <stijn@linux-ipv6.be>
 *
 * This program is free software; you can redistribute it and/or
 * modify it under the terms of the GNU General Public License
 * as published by the Free Software Foundation; either version 2
 * of the License, or (at your option) any later version.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program; if not, write to the Free Software
 * Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA  02111-1307, USA.
 */

#include <endian.h>
#include <stdio.h>
#include <stdlib.h>
#include <stddef.h>
#include <unistd.h>
#include <fcntl.h>
#include <sys/mman.h>
#include <sys/stat.h>
#include <string.h>
#include <errno.h>
#include <arpa/inet.h>

#include <sys/ioctl.h>
#include <mtd/mtd-user.h>
#include "mtd.h"
#include "wrgg.h"
#include "md5.h"

static inline uint32_t le32_to_cpu(uint8_t *buf)
{
	return buf[0] | buf[1] << 8 | buf[2] << 16 | buf[3] << 24;
}

ssize_t pread(int fd, void *buf, size_t count, off_t offset);
ssize_t pwrite(int fd, const void *buf, size_t count, off_t offset);

int
wrgg_fix_md5(struct wrgg03_header *shdr, int fd, size_t data_offset, size_t data_size)
{
	char *buf;
	ssize_t res;
	MD5_CTX ctx;
	unsigned char digest[16];
	int i;
	int err = 0;

	buf = malloc(data_size);
	if (!buf) {
		err = -ENOMEM;
		goto err_out;
	}

	res = pread(fd, buf, data_size, data_offset);
	if (res != data_size) {
		perror("pread");
		err = -EIO;
		goto err_free;
	}

	MD5_Init(&ctx);
	MD5_Update(&ctx, (char *)&shdr->offset, sizeof(shdr->offset));
	MD5_Update(&ctx, (char *)&shdr->dev_name, sizeof(shdr->dev_name));
	MD5_Update(&ctx, buf, data_size);
	MD5_Final(digest, &ctx);

	if (!memcmp(digest, shdr->digest, sizeof(digest))) {
		if (quiet < 2)
			fprintf(stderr, "the header is fixed already\n");
		return -1;
	}

	if (quiet < 2) {
		fprintf(stderr, "new size:%u, new MD5: ", data_size);
		for (i = 0; i < sizeof(digest); i++)
			fprintf(stderr, "%02x", digest[i]);

		fprintf(stderr, "\n");
	}

	/* update the size in the image */
	shdr->size = data_size;

	/* update the checksum in the image */
	memcpy(shdr->digest, digest, sizeof(digest));

err_free:
	free(buf);
err_out:
	return err;
}

int
mtd_fixwrgg(const char *mtd, size_t offset, size_t data_size)
{
	int fd;
	char *first_block;
	ssize_t res;
	size_t block_offset;
	size_t data_offset;
	struct wrgg03_header *shdr;

	if (quiet < 2)
		fprintf(stderr, "Trying to fix WRGG header in %s at 0x%x...\n",
			mtd, offset);

	block_offset = offset & ~(erasesize - 1);
	offset -= block_offset;

	fd = mtd_check_open(mtd);
	if(fd < 0) {
		fprintf(stderr, "Could not open mtd device: %s\n", mtd);
		exit(1);
	}

	if (block_offset + erasesize > mtdsize) {
		fprintf(stderr, "Offset too large, device size 0x%x\n",
			mtdsize);
		exit(1);
	}

	first_block = malloc(erasesize);
	if (!first_block) {
		perror("malloc");
		exit(1);
	}

	res = pread(fd, first_block, erasesize, block_offset);
	if (res != erasesize) {
		perror("pread");
		exit(1);
	}

	shdr = (struct wrgg03_header *)(first_block + offset);

	/* The magic is always stored in little-endian byte order */
	if (le32_to_cpu((uint8_t *)&shdr->magic1) != WRGG03_MAGIC) {
		fprintf(stderr, "magic1 = %x\n", shdr->magic1);
		fprintf(stderr, "WRGG03_MAGIC = %x\n", WRGG03_MAGIC);
		fprintf(stderr, "No WRGG header found\n");
		exit(1);
	} else if (!shdr->size) {
		fprintf(stderr, "WRGG entity with empty image\n");
		exit(1);
	}

	data_offset = offset + sizeof(struct wrgg03_header);
	if (!data_size)
		data_size = mtdsize - data_offset;
	if (data_size > shdr->size)
		data_size = shdr->size;
	if (wrgg_fix_md5(shdr, fd, data_offset, data_size))
		goto out;

	if (mtd_erase_block(fd, block_offset)) {
		fprintf(stderr, "Can't erease block at 0x%x (%s)\n",
			block_offset, strerror(errno));
		exit(1);
	}

	if (quiet < 2)
		fprintf(stderr, "Rewriting block at 0x%x\n", block_offset);

	if (pwrite(fd, first_block, erasesize, block_offset) != erasesize) {
		fprintf(stderr, "Error writing block (%s)\n", strerror(errno));
		exit(1);
	}

	if (quiet < 2)
		fprintf(stderr, "Done.\n");

out:
	close (fd);
	sync();

	return 0;
}