tools/firmware-utils/src/xorimage.c

   1 /*
   2  * xorimage.c - partially based on OpenWrt's addpattern.c
   3  *
   4  * This program is free software; you can redistribute it and/or modify
   5  * it under the terms of the GNU General Public License as published by
   6  * the Free Software Foundation; either version 2 of the License, or
   7  * (at your option) any later version.
   8  *
   9  * This program is distributed in the hope that it will be useful,
  10  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  11  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
  12  * General Public License for more details.
  13  *
  14  * You should have received a copy of the GNU General Public License
  15  * along with this program; if not, write to the Free Software
  16  * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
  17  */
  18
  19
  20 #include <stdio.h>
  21 #include <stdlib.h>
  22 #include <string.h>
  23 #include <stdbool.h>
  24 #include <stdint.h>
  25 #include <unistd.h>
  26 #include <sys/stat.h>
  27
  28 static char default_pattern[] = "12345678";
  29 static int is_hex_pattern;
  30
  31
  32 int xor_data(uint8_t *data, size_t len, const uint8_t *pattern, int p_len, int p_off)
  33 {
  34         int offset = p_off;
  35         while (len--) {
  36                 *data ^= pattern[offset];
  37                 data++;
  38                 offset = (offset + 1) % p_len;
  39         }
  40         return offset;
  41 }
  42
  43
  44 void usage(void) __attribute__ (( __noreturn__ ));
  45
  46 void usage(void)
  47 {
  48         fprintf(stderr, "Usage: xorimage [-i infile] [-o outfile] [-p <pattern>] [-x]\n");
  49         exit(EXIT_FAILURE);
  50 }
  51
  52
  53 int main(int argc, char **argv)
  54 {
  55         char buf[1024]; /* keep this at 1k or adjust garbage calc below */
  56         FILE *in = stdin;
  57         FILE *out = stdout;
  58         char *ifn = NULL;
  59         char *ofn = NULL;
  60         const char *pattern = default_pattern;
  61         char hex_pattern[128];
  62         unsigned int hex_buf;
  63         int c;
  64         int v0, v1, v2;
  65         size_t n;
  66         int p_len, p_off = 0;
  67
  68         while ((c = getopt(argc, argv, "i:o:p:xh")) != -1) {
  69                 switch (c) {
  70                         case 'i':
  71                                 ifn = optarg;
  72                                 break;
  73                         case 'o':
  74                                 ofn = optarg;
  75                                 break;
  76                         case 'p':
  77                                 pattern = optarg;
  78                                 break;
  79                         case 'x':
  80                                 is_hex_pattern = true;
  81                                 break;
  82                         case 'h':
  83                         default:
  84                                 usage();
  85                 }
  86         }
  87
  88         if (optind != argc || optind == 1) {
  89                 fprintf(stderr, "illegal arg \"%s\"\n", argv[optind]);
  90                 usage();
  91         }
  92
  93         if (ifn && !(in = fopen(ifn, "r"))) {
  94                 fprintf(stderr, "can not open \"%s\" for reading\n", ifn);
  95                 usage();
  96         }
  97
  98         if (ofn && !(out = fopen(ofn, "w"))) {
  99                 fprintf(stderr, "can not open \"%s\" for writing\n", ofn);
 100                 usage();
 101         }
 102
 103         p_len = strlen(pattern);
 104
 105         if (p_len == 0) {
 106                 fprintf(stderr, "pattern cannot be empty\n");
 107                 usage();
 108         }
 109
 110         if (is_hex_pattern) {
 111                 int i;
 112
 113                 if ((p_len / 2) > sizeof(hex_pattern)) {
 114                         fprintf(stderr, "provided hex pattern is too long\n");
 115                         usage();
 116                 }
 117
 118                 if (p_len % 2 != 0) {
 119                         fprintf(stderr, "the number of characters (hex) is incorrect\n");
 120                         usage();
 121                 }
 122
 123                 for (i = 0; i < (p_len / 2); i++) {
 124                         if (sscanf(pattern + (i * 2), "%2x", &hex_buf) < 0) {
 125                                 fprintf(stderr, "invalid hex digit around %d\n", i * 2);
 126                                 usage();
 127                         }
 128                         hex_pattern[i] = (char)hex_buf;
 129                 }
 130         }
 131
 132         while ((n = fread(buf, 1, sizeof(buf), in)) > 0) {
 133                 if (n < sizeof(buf)) {
 134                         if (ferror(in)) {
 135                         FREAD_ERROR:
 136                                 fprintf(stderr, "fread error\n");
 137                                 return EXIT_FAILURE;
 138                         }
 139                 }
 140
 141                 if (is_hex_pattern) {
 142                         p_off = xor_data(buf, n, hex_pattern, (p_len / 2),
 143                                          p_off);
 144                 } else {
 145                         p_off = xor_data(buf, n, pattern, p_len, p_off);
 146                 }
 147
 148                 if (!fwrite(buf, n, 1, out)) {
 149                 FWRITE_ERROR:
 150                         fprintf(stderr, "fwrite error\n");
 151                         return EXIT_FAILURE;
 152                 }
 153         }
 154
 155         if (ferror(in)) {
 156                 goto FREAD_ERROR;
 157         }
 158
 159         if (fflush(out)) {
 160                 goto FWRITE_ERROR;
 161         }
 162
 163         fclose(in);
 164         fclose(out);
 165
 166         return EXIT_SUCCESS;
 167 }