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Diffstat (limited to 'scripts/combined-image.sh')
| -rw-r--r-- | scripts/combined-image.sh | 32 |
1 files changed, 32 insertions, 0 deletions
diff --git a/scripts/combined-image.sh b/scripts/combined-image.sh new file mode 100644 index 0000000000..eecd3d7f20 --- /dev/null +++ b/scripts/combined-image.sh @@ -0,0 +1,32 @@ +#!/bin/sh + +BLKSZ=65536 + +[ -f "$1" -a -f "$2" ] || { + echo "Usage: $0 <kernel image> <rootfs image> [output file]" + exit 1 +} + +# Make sure provided images are 64k aligned. +kern=$(tempfile) +root=$(tempfile) +dd if="$1" of="$kern" bs=$BLKSZ conv=sync 2>/dev/null +dd if="$2" of="$root" bs=$BLKSZ conv=sync 2>/dev/null + +# Calculate md5sum over combined kernel and rootfs image. +md5=$(cat "$kern" "$root" | md5sum -) + +# Write image header followed by kernel and rootfs image. +# The header is padded to 64k, format is: +# CI magic word ("Combined Image") +# <kernel length> length of kernel encoded as zero padded 8 digit hex +# <rootfs length> length of rootfs encoded as zero padded 8 digit hex +# <md5sum> checksum of the combined kernel and rootfs image +( printf "CI%08x%08x%32s" \ + $(stat -c "%s" "$kern") $(stat -c "%s" "$root") "${md5%% *}" | \ + dd bs=$BLKSZ conv=sync; + cat "$kern" "$root" +) > ${3:-openwrt-combined.img} 2>/dev/null + +# Clean up. +rm -f "$kern" "$root" |