Root/tools/firmware-utils/src/mkbrnimg.c

1/*
2 * mkbrnimg.c - partially based on OpenWrt's wndr3700.c
3 *
4 * Copyright (C) 2011 Tobias Diedrich <ranma+openwrt@tdiedrich.de>
5 *
6 * This program is free software; you can redistribute it and/or
7 * modify it under the terms of the GNU General Public License,
8 * version 2 as published by the Free Software Foundation.
9 *
10 * This program is distributed in the hope that it will be useful,
11 * but WITHOUT ANY WARRANTY; without even the implied warranty of
12 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
13 * GNU General Public License for more details.
14 *
15 * You should have received a copy of the GNU General Public License
16 * along with this program; if not, write to the Free Software
17 * Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
18 */
19
20#include <stdio.h>
21#include <stdlib.h>
22#include <stddef.h>
23#include <unistd.h>
24#include <errno.h>
25#include <fcntl.h>
26#include <sys/mman.h>
27#include <string.h>
28#include <netinet/in.h>
29#include <inttypes.h>
30
31#define BPB 8 /* bits/byte */
32
33static uint32_t crc32[1<<BPB];
34
35static void init_crc32()
36{
37    const uint32_t poly = ntohl(0x2083b8ed);
38    int n;
39
40    for (n = 0; n < 1<<BPB; n++) {
41        uint32_t crc = n;
42        int bit;
43
44        for (bit = 0; bit < BPB; bit++)
45            crc = (crc & 1) ? (poly ^ (crc >> 1)) : (crc >> 1);
46        crc32[n] = crc;
47    }
48}
49
50static uint32_t crc32buf(unsigned char *buf, size_t len)
51{
52    uint32_t crc = 0xFFFFFFFF;
53
54    for (; len; len--, buf++)
55        crc = crc32[(uint8_t)crc ^ *buf] ^ (crc >> BPB);
56    return ~crc;
57}
58
59static void usage(const char *) __attribute__ (( __noreturn__ ));
60
61static void usage(const char *mess)
62{
63    fprintf(stderr, "Error: %s\n", mess);
64    fprintf(stderr, "Usage: mkbrnimg [-o output_file] [-m magic] [-s signature] kernel_file [additional files]\n");
65    fprintf(stderr, "\n");
66    exit(1);
67}
68
69static char *output_file = "default-brnImage";
70static uint32_t magic = 0x12345678;
71static char *signature = "BRNDTW502";
72
73static void parseopts(int *argc, char ***argv)
74{
75    char *endptr;
76    int res;
77
78    while ((res = getopt(*argc, *argv, "o:m:s:")) != -1) {
79        switch (res) {
80        default:
81            usage("Unknown option");
82            break;
83        case 'o':
84            output_file = optarg;
85            break;
86        case 'm':
87            magic = strtoul(optarg, &endptr, 0);
88            if (endptr == optarg || *endptr != 0)
89                usage("magic must be a decimal or hexadecimal 32-bit value");
90            break;
91        case 's':
92            signature = optarg;
93            break;
94        }
95    }
96    *argc -= optind;
97    *argv += optind;
98}
99
100static void appendfile(int outfd, char *path, int kernel) {
101    int fd;
102    size_t len, padded_len;
103    char *input_file;
104    uint32_t crc;
105    char padding[0x400];
106    char footer[12];
107
108    memset(padding, 0xff, sizeof(padding));
109
110    // mmap input_file
111    if ((fd = open(path, O_RDONLY)) < 0
112    || (len = lseek(fd, 0, SEEK_END)) < 0
113    || (input_file = mmap(0, len, PROT_READ, MAP_SHARED, fd, 0)) == (void *) (-1)
114    || close(fd) < 0)
115    {
116        fprintf(stderr, "Error mapping file '%s': %s\n", path, strerror(errno));
117        exit(1);
118    }
119
120    // kernel should be lzma compressed image, not uImage
121    if (kernel &&
122        (input_file[0] != (char)0x5d ||
123         input_file[1] != (char)0x00 ||
124         input_file[2] != (char)0x00 ||
125         input_file[3] != (char)0x80)) {
126        fprintf(stderr, "lzma signature not found on kernel image.\n");
127        exit(1);
128    }
129
130    init_crc32();
131    crc = crc32buf(input_file, len);
132    fprintf(stderr, "crc32 for '%s' is %08x.\n", path, crc);
133
134    // write the file
135    write(outfd, input_file, len);
136
137    // write padding
138    padded_len = ((len + sizeof(footer) + sizeof(padding) - 1) & ~(sizeof(padding) - 1)) - sizeof(footer);
139    fprintf(stderr, "len=%08x padded_len=%08x\n", len, padded_len);
140    write(outfd, padding, padded_len - len);
141
142    // write footer
143    footer[0] = (len >> 0) & 0xff;
144    footer[1] = (len >> 8) & 0xff;
145    footer[2] = (len >> 16) & 0xff;
146    footer[3] = (len >> 24) & 0xff;
147    footer[4] = (magic >> 0) & 0xff;
148    footer[5] = (magic >> 8) & 0xff;
149    footer[6] = (magic >> 16) & 0xff;
150    footer[7] = (magic >> 24) & 0xff;
151    footer[8] = (crc >> 0) & 0xff;
152    footer[9] = (crc >> 8) & 0xff;
153    footer[10] = (crc >> 16) & 0xff;
154    footer[11] = (crc >> 24) & 0xff;
155    write(outfd, footer, sizeof(footer));
156
157    munmap(input_file, len);
158}
159
160int main(int argc, char **argv)
161{
162    int outfd;
163    int i;
164
165    parseopts(&argc, &argv);
166
167    if (argc < 1)
168        usage("wrong number of arguments");
169
170    if ((outfd = open(output_file, O_WRONLY|O_CREAT|O_TRUNC, 0644)) == -1)
171    {
172        fprintf(stderr, "Error opening '%s' for writing: %s\n", output_file, strerror(errno));
173        exit(1);
174    }
175
176    for (i=0; i<argc; i++) {
177        appendfile(outfd, argv[i], i == 0);
178    }
179    write(outfd, signature, strlen(signature)+1);
180    close(outfd);
181
182    return 0;
183}
184

Archive Download this file

Branches:
backfire
history
master
release_2010-11-17
release_2010-12-14
release_2011-02-23
release_2011-05-28
release_2011-08-27
release_2011-11-13
release_2012-03-18
release_2012-04-09
release_2012-10-11
uclibc_nptl



interactive