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