35 lines
1022 B
Bash
35 lines
1022 B
Bash
#!/bin/sh
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BLKSZ=65536
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[ -f "$1" -a -f "$2" ] || {
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echo "Usage: $0 <kernel image> <rootfs image> [output file]"
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exit 1
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}
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IMAGE=${3:-openwrt-combined.img}
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# Make sure provided images are 64k aligned.
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kern="${IMAGE}.kernel"
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root="${IMAGE}.rootfs"
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dd if="$1" of="$kern" bs=$BLKSZ conv=sync 2>/dev/null
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dd if="$2" of="$root" bs=$BLKSZ conv=sync 2>/dev/null
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# Calculate md5sum over combined kernel and rootfs image.
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md5=$(cat "$kern" "$root" | mkhash md5)
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# Write image header followed by kernel and rootfs image.
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# The header is padded to 64k, format is:
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# CI magic word ("Combined Image")
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# <kernel length> length of kernel encoded as zero padded 8 digit hex
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# <rootfs length> length of rootfs encoded as zero padded 8 digit hex
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# <md5sum> checksum of the combined kernel and rootfs image
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( printf "CI%08x%08x%32s" \
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$(stat -c "%s" "$kern") $(stat -c "%s" "$root") "${md5%% *}" | \
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dd bs=$BLKSZ conv=sync;
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cat "$kern" "$root"
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) > ${IMAGE} 2>/dev/null
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# Clean up.
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rm -f "$kern" "$root"
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