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