xref: /openbmc/linux/scripts/extract-ikconfig (revision 1da177e4)
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"
7
8IKCFG_ST="0x49 0x4b 0x43 0x46 0x47 0x5f 0x53 0x54"
9IKCFG_ED="0x49 0x4b 0x43 0x46 0x47 0x5f 0x45 0x44"
10function dump_config {
11    typeset file="$1"
12
13    start=`$binoffset $file $IKCFG_ST 2>/dev/null`
14    [ "$?" != "0" ] && start="-1"
15    if [ "$start" -eq "-1" ]; then
16	return
17    fi
18    end=`$binoffset $file $IKCFG_ED 2>/dev/null`
19
20    let start="$start + 8"
21    let size="$end - $start"
22
23    head --bytes="$end" "$file" | tail --bytes="$size" | zcat
24
25    clean_up
26    exit 0
27}
28
29
30usage()
31{
32	echo "  usage: extract-ikconfig [b]zImage_filename"
33}
34
35clean_up()
36{
37	if [ "$TMPFILE" != "" ]; then
38		rm -f $TMPFILE
39	fi
40}
41
42if [ $# -lt 1 ]
43then
44	usage
45	exit 1
46fi
47
48TMPFILE="/tmp/ikconfig-$$"
49image="$1"
50
51# vmlinux: Attempt to dump the configuration from the file directly
52dump_config "$image"
53
54GZHDR1="0x1f 0x8b 0x08 0x00"
55GZHDR2="0x1f 0x8b 0x08 0x08"
56
57# vmlinux.gz: Check for a compressed images
58off=`$binoffset "$image" $GZHDR1 2>/dev/null`
59[ "$?" != "0" ] && off="-1"
60if [ "$off" -eq "-1" ]; then
61	off=`$binoffset "$image" $GZHDR2 2>/dev/null`
62	[ "$?" != "0" ] && off="-1"
63fi
64if [ "$off" -eq "0" ]; then
65	zcat <"$image" >"$TMPFILE"
66	dump_config "$TMPFILE"
67elif [ "$off" -ne "-1" ]; then
68	(dd ibs="$off" skip=1 count=0 && dd bs=512k) <"$image" 2>/dev/null | \
69		zcat >"$TMPFILE"
70	dump_config "$TMPFILE"
71fi
72
73echo "ERROR: Unable to extract kernel configuration information."
74echo "       This kernel image may not have the config info."
75
76clean_up
77exit 1
78