30 lines
842 B
Bash
Executable File
30 lines
842 B
Bash
Executable File
#!/usr/bin/env bash
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set -eo pipefail
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[ -t 0 ] && { echo "$0 must be run as a filter." >&2; exit 1; }
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mfile="$1"; [ -z "$1" ] && { echo "No image file specified!" >&2; exit 1; }
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BLOCKSIZE=`sed -nE 's/^#BLOCKSIZE=([0-9]+)$/\1/p' "$mfile"`
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[ -z "$BLOCKSIZE" ] && { echo "Mapfile does not specify blocksize!" >&2; exit 1; }
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map="$(grep -v ^\# "$mfile" \
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| awk '/[a-f0-9]{64}/{curfile=$2;next}{print curfile, $0}' \
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| sort -unk 3)"
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nitems=`wc -l <<<"$map"`
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shopt -s expand_aliases
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alias dd="dd bs=$BLOCKSIZE status=none"
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{
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pos=0
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for (( i = 0; i < $nitems; i++ )) do
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read hash lblock block lengt _ < <(sed $((i+1))'q;d' <<<"$map")
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dd if=/dev/stdin count=$((block-pos))
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dd if=/dev/stdin count=$((lengt-1)) >/dev/null
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dd if=pool/$hash count=$((lengt-1)) skip=$lblock
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pos=$((block+lengt-1))
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done
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dd if=/dev/stdin
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} > "${2:-/dev/stdout}"
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