1/* 2 * R7600.c - partially based on OpenWrt's add_header.c 3 * 4 * Copyright (C) 2009 Anael Orlinski <naouel@naouel.org> 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/* 21 * The add_header utility used by various vendors preprends the buf 22 * image with a header containing a CRC32 value which is generated for the 23 * model id + reserved space for CRC32 + buf, then replaces the reserved 24 * area with the actual CRC32. This replacement tool mimics this behavior. 25 */ 26 27#include <stdio.h> 28#include <stdlib.h> 29#include <stddef.h> 30#include <unistd.h> 31#include <errno.h> 32#include <fcntl.h> 33#include <sys/mman.h> 34#include <string.h> 35#include <netinet/in.h> 36#include <inttypes.h> 37 38#define BPB 8 /* bits/byte */ 39 40static uint32_t crc32[1<<BPB]; 41 42static void init_crc32() 43{ 44 const uint32_t poly = ntohl(0x2083b8ed); 45 int n; 46 47 for (n = 0; n < 1<<BPB; n++) { 48 uint32_t crc = n; 49 int bit; 50 51 for (bit = 0; bit < BPB; bit++) 52 crc = (crc & 1) ? (poly ^ (crc >> 1)) : (crc >> 1); 53 crc32[n] = crc; 54 } 55} 56 57static uint32_t crc32buf(unsigned char *buf, size_t len) 58{ 59 uint32_t crc = 0xFFFFFFFF; 60 61 for (; len; len--, buf++) 62 crc = crc32[(uint8_t)crc ^ *buf] ^ (crc >> BPB); 63 return ~crc; 64} 65 66struct header { 67 uint32_t magic; 68 uint32_t crc; 69 unsigned char stuff[56]; 70}; 71 72static void usage(const char *) __attribute__ (( __noreturn__ )); 73 74static void usage(const char *mess) 75{ 76 fprintf(stderr, "Error: %s\n", mess); 77 fprintf(stderr, "Usage: r7600 input_file output_file\n"); 78 fprintf(stderr, "\n"); 79 exit(1); 80} 81 82int main(int argc, char **argv) 83{ 84 off_t len; // of original buf 85 off_t buflen; // of the output file 86 int fd; 87 void *input_file; // pointer to the input file (mmmapped) 88 struct header header; 89 unsigned char *buf; // pointer to prefix + copy of original buf 90 91 // verify parameters 92 93 if (argc != 3) 94 usage("wrong number of arguments"); 95 96 // mmap input_file 97 if ((fd = open(argv[1], O_RDONLY)) < 0 98 || (len = lseek(fd, 0, SEEK_END)) < 0 99 || (input_file = mmap(0, len, PROT_READ, MAP_SHARED, fd, 0)) == (void *) (-1) 100 || close(fd) < 0) 101 { 102 fprintf(stderr, "Error loading file %s: %s\n", argv[1], strerror(errno)); 103 exit(1); 104 } 105 106 buflen = len; 107 108 init_crc32(); 109 110 // preload header 111 memcpy(&header, input_file, sizeof(header)); 112 113 header.magic = htonl(0x27051956); /* To sync with u-boot to change it to default 0x27051956 */ 114 header.crc = 0; 115 116 // create a firmware image in memory and copy the input_file to it 117 buf = malloc(buflen); 118 memcpy(buf, input_file, len); 119 120 // CRC of temporary header 121 header.crc = htonl(crc32buf((unsigned char*)&header, sizeof(header))); 122 123 memcpy(buf, &header, sizeof(header)); 124 125 // write the buf 126 if ((fd = open(argv[2], O_CREAT|O_WRONLY|O_TRUNC,0644)) < 0 127 || write(fd, buf, buflen) != buflen 128 || close(fd) < 0) 129 { 130 fprintf(stderr, "Error storing file %s: %s\n", argv[2], strerror(errno)); 131 exit(2); 132 } 133 134 free(buf); 135 136 munmap(input_file,len); 137 138 return 0; 139} 140