xref: /openbmc/linux/scripts/extract-ikconfig (revision a09d2831)
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"
11dump_config() {
12    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 $IKCFG_ED 2>/dev/null`
20    [ "$?" != "0" ] && end="-1"
21    if [ "$end" -eq "-1" ]; then
22	return
23    fi
24
25    start=`expr $start + 8`
26    size=`expr $end - $start`
27
28    dd if="$file" ibs=1 skip="$start" count="$size" 2>/dev/null | zcat
29
30    clean_up
31    exit 0
32}
33
34
35usage()
36{
37	echo "  usage: extract-ikconfig [b]zImage_filename"
38}
39
40clean_up()
41{
42	if [ "$TMPFILE" != "" ]; then
43		rm -f $TMPFILE
44	fi
45}
46
47if [ $# -lt 1 ]
48then
49	usage
50	exit 1
51fi
52
53TMPFILE=`mktemp -t ikconfig-XXXXXX` || exit 1
54image="$1"
55
56# vmlinux: Attempt to dump the configuration from the file directly
57dump_config "$image"
58
59GZHDR1="0x1f 0x8b 0x08 0x00"
60GZHDR2="0x1f 0x8b 0x08 0x08"
61
62ELFHDR="0x7f 0x45 0x4c 0x46"
63
64# vmlinux.gz: Check for a compressed images
65off=`$binoffset "$image" $GZHDR1 2>/dev/null`
66[ "$?" != "0" ] && off="-1"
67if [ "$off" -eq "-1" ]; then
68	off=`$binoffset "$image" $GZHDR2 2>/dev/null`
69	[ "$?" != "0" ] && off="-1"
70fi
71if [ "$off" -eq "0" ]; then
72	zcat <"$image" >"$TMPFILE"
73	dump_config "$TMPFILE"
74elif [ "$off" -ne "-1" ]; then
75	(dd ibs="$off" skip=1 count=0 && dd bs=512k) <"$image" 2>/dev/null | \
76		zcat >"$TMPFILE"
77	dump_config "$TMPFILE"
78
79# check if this is simply an ELF file
80else
81	off=`$binoffset "$image" $ELFHDR 2>/dev/null`
82	[ "$?" != "0" ] && off="-1"
83	if [ "$off" -eq "0" ]; then
84		dump_config "$image"
85	fi
86fi
87
88echo "ERROR: Unable to extract kernel configuration information."
89echo "       This kernel image may not have the config info."
90
91clean_up
92exit 1
93