[PATCH] tools: mkimage: Allow changing U-Boot image magic

[Hauke Mehrtens]

Extend mkimage with a new optional option -M to specify a special U-Boot
image magic number. OpenWrt ships images for about 30 different boards
with vendor boot loaders which are expecting the mkimage format, but
with a different image magic.

OpenWrt includes this patch for mkimage more than 10 years.
It was added by Gabor Juhos in this commit:
https://git.openwrt.org/?p=openwrt/openwrt.git;a=commitdiff;h=f3d2056b81b7a92d28402c22736534d84fe23cfe

Cc: Gabor Juhos <j4g8y7 at gmail.com>
Signed-off-by: Hauke Mehrtens <hauke at hauke-m.de>
---
 tools/default_image.c |  4 ++--
 tools/imagetool.h     |  1 +
 tools/mkimage.c       | 14 ++++++++++++--
 3 files changed, 15 insertions(+), 4 deletions(-)

diff --git a/tools/default_image.c b/tools/default_image.c
index 0ac3382003..514edf05a5 100644
--- a/tools/default_image.c
+++ b/tools/default_image.c
@@ -57,7 +57,7 @@ static int image_verify_header(unsigned char *ptr, int image_size,
 	 */
 	memcpy(hdr, ptr, sizeof(struct legacy_img_hdr));
 
-	if (be32_to_cpu(hdr->ih_magic) != IH_MAGIC) {
+	if (be32_to_cpu(hdr->ih_magic) != params->magic) {
 		debug("%s: Bad Magic Number: \"%s\" is no valid image\n",
 		      params->cmdname, params->imagefile);
 		return -FDT_ERR_BADMAGIC;
@@ -126,7 +126,7 @@ static void image_set_header(void *ptr, struct stat *sbuf, int ifd,
 	}
 
 	/* Build new header */
-	image_set_magic(hdr, IH_MAGIC);
+	image_set_magic(hdr, params->magic);
 	image_set_time(hdr, time);
 	image_set_size(hdr, imagesize);
 	image_set_load(hdr, addr);
diff --git a/tools/imagetool.h b/tools/imagetool.h
index ca7c2e48ba..5e61228a5f 100644
--- a/tools/imagetool.h
+++ b/tools/imagetool.h
@@ -59,6 +59,7 @@ struct image_tool_params {
 	int arch;
 	int type;
 	int comp;
+	unsigned int magic;
 	char *dtc;
 	unsigned int addr;
 	unsigned int ep;
diff --git a/tools/mkimage.c b/tools/mkimage.c
index 8306861ce5..957abe115c 100644
--- a/tools/mkimage.c
+++ b/tools/mkimage.c
@@ -26,6 +26,7 @@ static struct image_tool_params params = {
 	.arch = IH_ARCH_PPC,
 	.type = IH_TYPE_KERNEL,
 	.comp = IH_COMP_GZIP,
+	.magic = IH_MAGIC,
 	.dtc = MKIMAGE_DEFAULT_DTC_OPTIONS,
 	.imagename = "",
 	.imagename2 = "",
@@ -89,11 +90,12 @@ static void usage(const char *msg)
 			 "          -q ==> quiet\n",
 		params.cmdname);
 	fprintf(stderr,
-		"       %s [-x] -A arch -O os -T type -C comp -a addr -e ep -n name -d data_file[:data_file...] image\n"
+		"       %s [-x] -A arch -O os -T type -C comp -M magic -a addr -e ep -n name -d data_file[:data_file...] image\n"
 		"          -A ==> set architecture to 'arch'\n"
 		"          -O ==> set operating system to 'os'\n"
 		"          -T ==> set image type to 'type'\n"
 		"          -C ==> set compression type 'comp'\n"
+		"          -M ==> set image magic to 'magic' (hex)\n"
 		"          -a ==> set load address to 'addr' (hex)\n"
 		"          -e ==> set entry point to 'ep' (hex)\n"
 		"          -n ==> set image name to 'name'\n"
@@ -159,7 +161,7 @@ static int add_content(int type, const char *fname)
 }
 
 static const char optstring[] =
-	"a:A:b:B:c:C:d:D:e:Ef:Fg:G:i:k:K:ln:N:o:O:p:qrR:stT:vVx";
+	"a:A:b:B:c:C:d:D:e:Ef:Fg:G:i:k:K:lM:n:N:o:O:p:qrR:stT:vVx";
 
 static const struct option longopts[] = {
 	{ "load-address", required_argument, NULL, 'a' },
@@ -298,6 +300,14 @@ static void process_args(int argc, char **argv)
 		case 'l':
 			params.lflag = 1;
 			break;
+		case 'M':
+			params.magic = strtoull(optarg, &ptr, 16);
+			if (*ptr) {
+				fprintf(stderr,	"%s: invalid magic %s\n",
+					params.cmdname, optarg);
+				exit(EXIT_FAILURE);
+			}
+			break;
 		case 'n':
 			params.imagename = optarg;
 			break;
-- 
2.39.0