1#!/bin/sh
2# extracts .config info from a [b]zImage file
3# uses: binoffset (new), dd, zcat, strings, grep
4# $arg1 is [b]zImage filename
5
6binoffset="./scripts/binoffset"
7test -e $binoffset || cc -o $binoffset ./scripts/binoffset.c || exit 1
8
9IKCFG_ST="0x49 0x4b 0x43 0x46 0x47 0x5f 0x53 0x54"
10IKCFG_ED="0x49 0x4b 0x43 0x46 0x47 0x5f 0x45 0x44"
11function dump_config {
12    typeset file="$1"
13
14    start=`$binoffset $file $IKCFG_ST 2>/dev/null`
15    [ "$?" != "0" ] && start="-1"
16    if [ "$start" -eq "-1" ]; then
17	return
18    fi
19    end=`$binoffset $file $IKCFG_ED 2>/dev/null`
20
21    let start="$start + 8"
22    let size="$end - $start"
23
24    dd if="$file" ibs=1 skip="$start" count="$size" 2>/dev/null | zcat
25
26    clean_up
27    exit 0
28}
29
30
31usage()
32{
33	echo "  usage: extract-ikconfig [b]zImage_filename"
34}
35
36clean_up()
37{
38	if [ "$TMPFILE" != "" ]; then
39		rm -f $TMPFILE
40	fi
41}
42
43if [ $# -lt 1 ]
44then
45	usage
46	exit 1
47fi
48
49TMPFILE=`mktemp -t ikconfig-XXXXXX` || exit 1
50image="$1"
51
52# vmlinux: Attempt to dump the configuration from the file directly
53dump_config "$image"
54
55GZHDR1="0x1f 0x8b 0x08 0x00"
56GZHDR2="0x1f 0x8b 0x08 0x08"
57
58# vmlinux.gz: Check for a compressed images
59off=`$binoffset "$image" $GZHDR1 2>/dev/null`
60[ "$?" != "0" ] && off="-1"
61if [ "$off" -eq "-1" ]; then
62	off=`$binoffset "$image" $GZHDR2 2>/dev/null`
63	[ "$?" != "0" ] && off="-1"
64fi
65if [ "$off" -eq "0" ]; then
66	zcat <"$image" >"$TMPFILE"
67	dump_config "$TMPFILE"
68elif [ "$off" -ne "-1" ]; then
69	(dd ibs="$off" skip=1 count=0 && dd bs=512k) <"$image" 2>/dev/null | \
70		zcat >"$TMPFILE"
71	dump_config "$TMPFILE"
72fi
73
74echo "ERROR: Unable to extract kernel configuration information."
75echo "       This kernel image may not have the config info."
76
77clean_up
78exit 1
79