kconfig: have extract-ikconfig read ELF files
[linux-2.6.git] / scripts / extract-ikconfig
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
6 binoffset="./scripts/binoffset"
7 test -e $binoffset || cc -o $binoffset ./scripts/binoffset.c || exit 1
8
9 IKCFG_ST="0x49 0x4b 0x43 0x46 0x47 0x5f 0x53 0x54"
10 IKCFG_ED="0x49 0x4b 0x43 0x46 0x47 0x5f 0x45 0x44"
11 dump_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
35 usage()
36 {
37         echo "  usage: extract-ikconfig [b]zImage_filename"
38 }
39
40 clean_up()
41 {
42         if [ "$TMPFILE" != "" ]; then
43                 rm -f $TMPFILE
44         fi
45 }
46
47 if [ $# -lt 1 ]
48 then
49         usage
50         exit 1
51 fi
52
53 TMPFILE=`mktemp -t ikconfig-XXXXXX` || exit 1
54 image="$1"
55
56 # vmlinux: Attempt to dump the configuration from the file directly
57 dump_config "$image"
58
59 GZHDR1="0x1f 0x8b 0x08 0x00"
60 GZHDR2="0x1f 0x8b 0x08 0x08"
61
62 ELFHDR="0x7f 0x45 0x4c 0x46"
63
64 # vmlinux.gz: Check for a compressed images
65 off=`$binoffset "$image" $GZHDR1 2>/dev/null`
66 [ "$?" != "0" ] && off="-1"
67 if [ "$off" -eq "-1" ]; then
68         off=`$binoffset "$image" $GZHDR2 2>/dev/null`
69         [ "$?" != "0" ] && off="-1"
70 fi
71 if [ "$off" -eq "0" ]; then
72         zcat <"$image" >"$TMPFILE"
73         dump_config "$TMPFILE"
74 elif [ "$off" -ne "-1" ]; then
75         (dd ibs="$off" skip=1 count=0 && dd bs=512k) <"$image" 2>/dev/null | \
76                 zcat >"$TMPFILE"
77         dump_config "$TMPFILE"
78
79 # check if this is simply an ELF file
80 else
81         off=`$binoffset "$image" $ELFHDR 2>/dev/null`
82         [ "$?" != "0" ] && off="-1"
83         if [ "$off" -eq "0" ]; then
84                 dump_config "$image"
85         fi
86 fi
87
88 echo "ERROR: Unable to extract kernel configuration information."
89 echo "       This kernel image may not have the config info."
90
91 clean_up
92 exit 1