LXR linux/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
   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