#!/bin/sh # ---------------------------------------------------------------------- # extract-ikconfig - Extract the .config file from a kernel image # # This will only work when the kernel was compiled with CONFIG_IKCONFIG. # # The obscure use of the "tr" filter is to work around older versions of # "grep" that report the byte offset of the line instead of the pattern. # # (c) 2009, Dick Streefland <dick@streefland.net> # Licensed under the terms of the GNU General Public License. # ---------------------------------------------------------------------- gz1='\037\213\010' gz2='01' cf1='IKCFG_ST\037\213\010' cf2='0123456789' dump_config() { if pos=`tr "$cf1\n$cf2" "\n$cf2=" < "$1" | grep -abo "^$cf2"` then pos=${pos%%:*} tail -c+$(($pos+8)) "$1" | zcat -q exit 0 fi } # Check invocation: me=${0##*/} img=$1 if [ $# -ne 1 -o ! -s "$img" ] then echo "Usage: $me <kernel-image>" >&2 exit 2 fi # Initial attempt for uncompressed images or objects: dump_config "$img" # That didn't work, so decompress and try again: tmp=/tmp/ikconfig$$ trap "rm -f $tmp" 0 for pos in `tr "$gz1\n$gz2" "\n$gz2=" < "$img" | grep -abo "^$gz2"` do pos=${pos%%:*} tail -c+$pos "$img" | zcat 2> /dev/null > $tmp dump_config $tmp done # Bail out: echo "$me: Cannot find kernel config." >&2 exit 1