scripts/extract-ikconfig

   1 #! /bin/bash
   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 TMPFILE=""
   7
   8 usage()
   9 {
  10         echo "  usage: extract-ikconfig [b]zImage_filename"
  11 }
  12
  13 clean_up()
  14 {
  15         if [ -z $ISCOMP ]
  16         then
  17                 rm -f $TMPFILE
  18         fi
  19 }
  20
  21 if [ $# -lt 1 ]
  22 then
  23         usage
  24         exit
  25 fi
  26
  27 image=$1
  28
  29 # There are two gzip headers, as well as arches which don't compress their
  30 # kernel.
  31 GZHDR="0x1f 0x8b 0x08 0x00"
  32 if [ `binoffset $image $GZHDR >/dev/null 2>&1 ; echo $?` -ne 0 ]
  33 then
  34         GZHDR="0x1f 0x8b 0x08 0x08"
  35         if [ `binoffset $image $GZHDR >/dev/null 2>&1 ; echo $?` -ne 0 ]
  36         then
  37                 ISCOMP=0
  38         fi
  39 fi
  40
  41 PID=$$
  42
  43 # Extract and uncompress the kernel image if necessary
  44 if [ -z $ISCOMP ]
  45 then
  46         TMPFILE="/tmp/`basename $image`.vmlin.$PID"
  47         dd if=$image bs=1 skip=`binoffset $image $GZHDR` 2> /dev/null | zcat > $TMPFILE
  48 else
  49         TMPFILE=$image
  50 fi
  51
  52 # Look for strings.
  53 strings $TMPFILE | grep "CONFIG_BEGIN=n" > /dev/null
  54 if [ $? -eq 0 ]
  55 then
  56         strings $TMPFILE | awk "/CONFIG_BEGIN=n/,/CONFIG_END=n/" > $image.oldconfig.$PID
  57 else
  58         echo "ERROR: Unable to extract kernel configuration information."
  59         echo "       This kernel image may not have the config info."
  60         clean_up
  61         exit 1
  62 fi
  63
  64 echo "Kernel configuration written to $image.oldconfig.$PID"
  65 clean_up
  66 exit 0