/* * add_header.c - partially based on OpenWrt's motorola-bin.c * * Copyright (C) 2008 Imre Kaloz * Gabor Juhos * * This program is free software; you can redistribute it and/or * modify it under the terms of the GNU General Public License, * version 2 as published by the Free Software Foundation. * * 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. */ /* * The add_header utility used by various vendors preprends the buf * image with a header containing a CRC32 value which is generated for the * model id + reserved space for CRC32 + buf, then replaces the reserved * area with the actual CRC32. This replacement tool mimics this behavior. */ #include #include #include #include #include #include #include #include #include #include #define BPB 8 /* bits/byte */ static uint32_t crc32[1<> 1)) : (crc >> 1); crc32[n] = crc; } } static uint32_t crc32buf(unsigned char *buf, size_t len) { uint32_t crc = 0xFFFFFFFF; for (; len; len--, buf++) crc = crc32[(uint8_t)crc ^ *buf] ^ (crc >> BPB); return ~crc; } struct header { unsigned char model[16]; uint32_t crc; }; static void usage(const char *) __attribute__ (( __noreturn__ )); static void usage(const char *mess) { fprintf(stderr, "Error: %s\n", mess); fprintf(stderr, "Usage: add_header model_id input_file output_file\n"); fprintf(stderr, "\n"); exit(1); } int main(int argc, char **argv) { off_t len; // of original buf off_t buflen; // of the output file int fd; void *input_file; // pointer to the input file (mmmapped) struct header header; unsigned char *buf; // pointer to prefix + copy of original buf // verify parameters if (argc != 4) usage("wrong number of arguments"); // mmap input_file if ((fd = open(argv[2], O_RDONLY)) < 0 || (len = lseek(fd, 0, SEEK_END)) < 0 || (input_file = mmap(0, len, PROT_READ, MAP_SHARED, fd, 0)) == (void *) (-1) || close(fd) < 0) { fprintf(stderr, "Error loading file %s: %s\n", argv[2], strerror(errno)); exit(1); } buflen = len + sizeof(header); init_crc32(); // copy model name into header strncpy(header.model, argv[1], sizeof(header.model)); header.crc = 0; // create a firmware image in memory and copy the input_file to it buf = malloc(buflen); memcpy(buf, &header, sizeof(header)); memcpy(&buf[sizeof(header)], input_file, len); // CRC of temporary header + buf header.crc = htonl(crc32buf(buf, buflen)); memcpy(buf, &header, sizeof(header)); // write the buf if ((fd = open(argv[3], O_CREAT|O_WRONLY|O_TRUNC,0644)) < 0 || write(fd, buf, buflen) != buflen || close(fd) < 0) { fprintf(stderr, "Error storing file %s: %s\n", argv[3], strerror(errno)); exit(2); } free(buf); munmap(input_file,len); return 0; } 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