src/mkheader_gemtek.c

   1 // SPDX-License-Identifier: GPL-2.0-or-later
   2 /*
   3  * Copyright (C) 2014  Claudio Leite <leitec@staticky.com>
   4  */
   5
   6 /*
   7  * Builds a proper flash image for routers using some Gemtek
   8  * OEM boards. These include the Airlink101 AR725W, the
   9  * Asante SmartHub 600 (AWRT-600N), and Linksys WRT100/110.
  10  *
  11  * The resulting image is compatible with the factory firmware
  12  * web upgrade and TFTP interface.
  13  *
  14  * To build:
  15  *  gcc -O2 -o mkheader_gemtek mkheader_gemtek.c -lz
  16  *
  17  * Claudio Leite <leitec@staticky.com>
  18  */
  19
  20 #include <stdio.h>
  21 #include <stdlib.h>
  22 #include <stdint.h>
  23 #include <string.h>
  24
  25 #include <zlib.h>               /* for crc32() */
  26
  27 /*
  28  * The header is in little-endian format. In case
  29  * we are on a BE host, we need to swap binary
  30  * values.
  31  */
  32 #ifdef __APPLE__
  33 # include <libkern/OSByteOrder.h>
  34 # define le32 OSSwapHostToLittleInt32
  35 #else
  36 # if defined(__linux__)
  37 #  include <endian.h>
  38 #  if __BYTE_ORDER == __BIG_ENDIAN
  39 #   define CPU_BIG_ENDIAN
  40 #  endif
  41 # else
  42 #  include <sys/endian.h>               /* BSD's should have this */
  43 #  if _BYTE_ORDER == _BIG_ENDIAN
  44 #   define CPU_BIG_ENDIAN
  45 #  endif
  46 # endif
  47 # ifdef CPU_BIG_ENDIAN
  48 #  define le32(x) (((x & 0xff000000) >> 24) | \
  49                    ((x & 0x00ff0000) >> 8)  | \
  50                    ((x & 0x0000ff00) << 8)  | \
  51                    ((x & 0x000000ff) << 24))
  52 # else
  53 #  define le32(x) (x)
  54 # endif
  55 #endif
  56
  57 struct gemtek_header {
  58         uint8_t         magic[4];
  59         uint8_t         version[4];
  60         uint32_t        product_id;
  61         uint32_t        imagesz;
  62         uint32_t        checksum;
  63         uint32_t        fast_checksum;
  64         uint8_t         build[4];
  65         uint8_t         lang[4];
  66 };
  67
  68 #define HDRLEN  sizeof(struct gemtek_header)
  69
  70 struct machines {
  71         char           *desc;
  72         char           *id;
  73         uint32_t        maxsize;
  74         struct gemtek_header header;
  75 };
  76
  77 struct machines mach_def[] = {
  78         {"Airlink101 AR725W", "ar725w", 0x340000,
  79                 {"GMTK", "1003", le32(0x03000001), 0, 0,
  80                   0, "01\0\0", "EN\0\0"}},
  81         {"Asante AWRT-600N", "awrt600n", 0x340000,
  82                 {"A600", "1005", le32(0x03000001), 0, 0,
  83                   0, "01\0\0", "EN\0\0"}},
  84         {"Linksys WRT100", "wrt100", 0x320000,
  85                 {"GMTK", "1007", le32(0x03040001), 0, 0,
  86                   0, "2\0\0\0", "EN\0\0"}},
  87         {"Linksys WRT110", "wrt110", 0x320000,
  88                 {"GMTK", "1007", le32(0x03040001), 0, 0,
  89                   0, "2\0\0\0", "EN\0\0"}},
  90         {0}
  91 };
  92
  93 int
  94 main(int argc, char *argv[])
  95 {
  96         unsigned long   res, flen;
  97         struct gemtek_header my_hdr;
  98         FILE           *f, *f_out;
  99         int             image_type = -1, index;
 100         uint8_t        *buf;
 101         uint32_t        crc;
 102
 103         if (argc < 3) {
 104                 fprintf(stderr, "mkheader_gemtek <uImage> <webflash image> [machine ID]\n");
 105                 fprintf(stderr, "  where [machine ID] is one of:\n");
 106                 for (index = 0; mach_def[index].desc != 0; index++) {
 107                         fprintf(stderr, "    %-10s  %s", mach_def[index].id, mach_def[index].desc);
 108                         if (index == 0)
 109                                 fprintf(stderr, " (default)\n");
 110                         else
 111                                 fprintf(stderr, "\n");
 112                 }
 113
 114                 exit(-1);
 115         }
 116
 117         if (argc == 4) {
 118                 for(index = 0; mach_def[index].id != 0; index++) {
 119                         if(strcmp(mach_def[index].id, argv[3]) == 0) {
 120                                 image_type = index;
 121                                 break;
 122                         }
 123                 }
 124
 125                 if(image_type == -1) {
 126                         fprintf(stderr, "\nERROR: invalid machine type\n");
 127                         exit(-1);
 128                 }
 129         } else
 130                 image_type = 0;
 131
 132         printf("Opening %s...\n", argv[1]);
 133
 134         f = fopen(argv[1], "r");
 135         if(!f) {
 136                 fprintf(stderr, "\nERROR: couldn't open input image\n");
 137                 exit(-1);
 138         }
 139
 140         fseek(f, 0, SEEK_END);
 141         flen = (unsigned long) ftell(f);
 142
 143         printf("  %lu (0x%lX) bytes long\n", flen, flen);
 144
 145         if (flen > mach_def[image_type].maxsize) {
 146                 fprintf(stderr, "\nERROR: image exceeds maximum compatible size\n");
 147                 goto f_error;
 148         }
 149
 150         buf = malloc(flen + HDRLEN);
 151         if (!buf) {
 152                 fprintf(stderr, "\nERROR: couldn't allocate buffer\n");
 153                 goto f_error;
 154         }
 155         rewind(f);
 156         res = fread(buf + HDRLEN, 1, flen, f);
 157         if (res != flen) {
 158                 perror("Couldn't read entire file: fread()");
 159                 goto f_error;
 160         }
 161         fclose(f);
 162
 163         printf("\nCreating %s...\n", argv[2]);
 164
 165         memcpy(&my_hdr, &mach_def[image_type].header, HDRLEN);
 166
 167         printf("  Using %s magic\n", mach_def[image_type].desc);
 168
 169         my_hdr.imagesz = le32(flen + HDRLEN);
 170         memcpy(my_hdr.lang, "EN", 2);
 171
 172         memcpy(buf, &my_hdr, HDRLEN);
 173
 174         crc = crc32(0, buf, flen + HDRLEN);
 175         printf("  CRC32: %08X\n", crc);
 176
 177         my_hdr.checksum = le32(crc);
 178         memcpy(buf, &my_hdr, HDRLEN);
 179
 180         printf("  Writing...\n");
 181
 182         f_out = fopen(argv[2], "w");
 183         if(!f_out) {
 184                 fprintf(stderr, "\nERROR: couldn't open output image\n");
 185                 exit(-1);
 186         }
 187
 188         fwrite(buf, 1, flen + HDRLEN, f_out);
 189
 190         fclose(f_out);
 191
 192         free(buf);
 193         return 0;
 194
 195 f_error:
 196         fclose(f);
 197         exit(-1);
 198 }