2ca643faebaf4114944ebaa38464c641d7369445
2 * xorimage.c - partially based on OpenWrt's addpattern.c
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.
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.
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
28 static char default_pattern
[] = "12345678";
29 static int is_hex_pattern
;
32 int xor_data(uint8_t *data
, size_t len
, const uint8_t *pattern
, int p_len
, int p_off
)
36 *data
^= pattern
[offset
];
38 offset
= (offset
+ 1) % p_len
;
44 void usage(void) __attribute__ (( __noreturn__
));
48 fprintf(stderr
, "Usage: xorimage [-i infile] [-o outfile] [-p <pattern>] [-x]\n");
53 int main(int argc
, char **argv
)
55 char buf
[1024]; /* keep this at 1k or adjust garbage calc below */
60 const char *pattern
= default_pattern
;
61 char hex_pattern
[128];
68 while ((c
= getopt(argc
, argv
, "i:o:p:xh")) != -1) {
80 is_hex_pattern
= true;
88 if (optind
!= argc
|| optind
== 1) {
89 fprintf(stderr
, "illegal arg \"%s\"\n", argv
[optind
]);
93 if (ifn
&& !(in
= fopen(ifn
, "r"))) {
94 fprintf(stderr
, "can not open \"%s\" for reading\n", ifn
);
98 if (ofn
&& !(out
= fopen(ofn
, "w"))) {
99 fprintf(stderr
, "can not open \"%s\" for writing\n", ofn
);
103 p_len
= strlen(pattern
);
106 fprintf(stderr
, "pattern cannot be empty\n");
110 if (is_hex_pattern
) {
113 if ((p_len
/ 2) > sizeof(hex_pattern
)) {
114 fprintf(stderr
, "provided hex pattern is too long\n");
118 if (p_len
% 2 != 0) {
119 fprintf(stderr
, "the number of characters (hex) is incorrect\n");
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);
128 hex_pattern
[i
] = (char)hex_buf
;
132 while ((n
= fread(buf
, 1, sizeof(buf
), in
)) > 0) {
133 if (n
< sizeof(buf
)) {
136 fprintf(stderr
, "fread error\n");
141 if (is_hex_pattern
) {
142 p_off
= xor_data(buf
, n
, hex_pattern
, (p_len
/ 2),
145 p_off
= xor_data(buf
, n
, pattern
, p_len
, p_off
);
148 if (!fwrite(buf
, n
, 1, out
)) {
150 fprintf(stderr
, "fwrite error\n");