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 function 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
  31 usage()
  32 {
  33         echo "  usage: extract-ikconfig [b]zImage_filename"
  34 }
  35
  36 clean_up()
  37 {
  38         if [ "$TMPFILE" != "" ]; then
  39                 rm -f $TMPFILE
  40         fi
  41 }
  42
  43 if [ $# -lt 1 ]
  44 then
  45         usage
  46         exit 1
  47 fi
  48
  49 TMPFILE=`mktemp -t ikconfig-XXXXXX` || exit 1
  50 image="$1"
  51
  52 # vmlinux: Attempt to dump the configuration from the file directly
  53 dump_config "$image"
  54
  55 GZHDR1="0x1f 0x8b 0x08 0x00"
  56 GZHDR2="0x1f 0x8b 0x08 0x08"
  57
  58 # vmlinux.gz: Check for a compressed images
  59 off=`$binoffset "$image" $GZHDR1 2>/dev/null`
  60 [ "$?" != "0" ] && off="-1"
  61 if [ "$off" -eq "-1" ]; then
  62         off=`$binoffset "$image" $GZHDR2 2>/dev/null`
  63         [ "$?" != "0" ] && off="-1"
  64 fi
  65 if [ "$off" -eq "0" ]; then
  66         zcat <"$image" >"$TMPFILE"
  67         dump_config "$TMPFILE"
  68 elif [ "$off" -ne "-1" ]; then
  69         (dd ibs="$off" skip=1 count=0 && dd bs=512k) <"$image" 2>/dev/null | \
  70                 zcat >"$TMPFILE"
  71         dump_config "$TMPFILE"
  72 fi
  73
  74 echo "ERROR: Unable to extract kernel configuration information."
  75 echo "       This kernel image may not have the config info."
  76
  77 clean_up
  78 exit 1