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

[Simon Glass]

Hi,

On Sun, 22 Jan 2023 at 07:20, Hauke Mehrtens <hauke at hauke-m.de> wrote:
>
> 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(-)

Strange...what is the different magic for?

>
> 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
>

REgards,
Simon