firmware-utils: add hex pattern mode for xorimage

This commit adds "hex pattern mode" to xorimage. This mode allows xor
with a hexadecimal pattern that cannot be expressed with ASCII
charactors.

usage (example):
  xorimage -i firmware.bin -o firmware.bin.new -p 6A57190601121E4C -x

Signed-off-by: INAGAKI Hiroshi <musashino.open@gmail.com>
Signed-off-by: Christian Lamparter <chunkeey@gmail.com> (fix checkpatch)

tools/firmware-utils/src/xorimage.c

@@ -20,11 +20,13 @@
 #include <stdio.h>
 #include <stdlib.h>
 #include <string.h>
+#include <stdbool.h>
 #include <stdint.h>
 #include <unistd.h>
 #include <sys/stat.h>
 
 static char default_pattern[] = "12345678";
+static int is_hex_pattern;
 
 
 int xor_data(uint8_t *data, size_t len, const uint8_t *pattern, int p_len, int p_off)
@@ -43,7 +45,7 @@ void usage(void) __attribute__ (( __noreturn__ ));
 
 void usage(void)
 {
-	fprintf(stderr, "Usage: xorimage [-i infile] [-o outfile] [-p <pattern>]\n");
+	fprintf(stderr, "Usage: xorimage [-i infile] [-o outfile] [-p <pattern>] [-x]\n");
 	exit(EXIT_FAILURE);
 }
 
@@ -56,12 +58,14 @@ int main(int argc, char **argv)
 	char *ifn = NULL;
 	char *ofn = NULL;
 	const char *pattern = default_pattern;
+	char hex_pattern[128];
+	unsigned int hex_buf;
 	int c;
 	int v0, v1, v2;
 	size_t n;
 	int p_len, p_off = 0;
 
-	while ((c = getopt(argc, argv, "i:o:p:h")) != -1) {
+	while ((c = getopt(argc, argv, "i:o:p:xh")) != -1) {
 		switch (c) {
 			case 'i':
 				ifn = optarg;
@@ -72,6 +76,9 @@ int main(int argc, char **argv)
 			case 'p':
 				pattern = optarg;
 				break;
+			case 'x':
+				is_hex_pattern = true;
+				break;
 			case 'h':
 			default:
 				usage();
@@ -100,6 +107,27 @@ int main(int argc, char **argv)
 		usage();
 	}
 
+	if (is_hex_pattern) {
+		int i;
+
+		if ((p_len / 2) > sizeof(hex_pattern)) {
+			fprintf(stderr, "provided hex pattern is too long\n");
+			usage();
+		}
+
+		if (p_len % 2 != 0) {
+			fprintf(stderr, "the number of characters (hex) is incorrect\n");
+			usage();
+		}
+
+		for (i = 0; i < (p_len / 2); i++) {
+			if (sscanf(pattern + (i * 2), "%2x", &hex_buf) < 0) {
+				fprintf(stderr, "invalid hex digit around %d\n", i * 2);
+				usage();
+			}
+			hex_pattern[i] = (char)hex_buf;
+		}
+	}
 
 	while ((n = fread(buf, 1, sizeof(buf), in)) > 0) {
 		if (n < sizeof(buf)) {
@@ -110,7 +138,12 @@ int main(int argc, char **argv)
 			}
 		}
 
-		p_off = xor_data(buf, n, pattern, p_len, p_off);
+		if (is_hex_pattern) {
+			p_off = xor_data(buf, n, hex_pattern, (p_len / 2),
+					 p_off);
+		} else {
+			p_off = xor_data(buf, n, pattern, p_len, p_off);
+		}
 
 		if (!fwrite(buf, n, 1, out)) {
 		FWRITE_ERROR: