#!/bin/sh
# bzexe: compressor for Unix executables.
# Use this only for binaries that you do not use frequently.
# 20010801: version using bzip2 by RJVB.
#
# The compressed version is a shell script which decompresses itself after
# skipping $skip lines of shell commands.  We try invoking the compressed
# executable with the original name (for programs looking at their name).
# We also try to retain the original file permissions on the compressed file.
# For safety reasons, bzexe will not create setuid or setgid shell scripts.

# WARNING: the first line of this file must be either : or #!/bin/sh
# The : is required for some old versions of csh.
# On Ultrix, /bin/sh is too buggy, change the first line to: #!/bin/sh5

# Original decompressing shellscript. This doesn't allow running multiple copies
# of a compressed executable. RJVB added some lines that check first if "/tmp/$prog"
# already exists and is executable. If so, it is executed (once more). Every
# incarnation will attempt to remove the temp. executable, which *might* cause
# problems if your UNIX allows removing busy files (e.g. over NFS).
# skip=18
# if tail +$skip $0 | "/usr/local/bin"/bzip2 -cd > /tmp/bztmp$$; then
#   /bin/chmod 700 /tmp/bztmp$$
#   prog="`echo $0 | /bin/sed 's|^.*/||'`"
#   if /bin/ln /tmp/bztmp$$ "/tmp/$prog" 2>/dev/null; then
#     trap '/bin/rm -f /tmp/bztmp$$ "/tmp/$prog"; exit $res' 0
#     (/bin/sleep 5; /bin/rm -f /tmp/bztmp$$ "/tmp/$prog") 2>/dev/null &
#     /tmp/"$prog" ${1+"$@"}; res=$?
#   else
#     trap '/bin/rm -f /tmp/bztmp$$; exit $res' 0
#     (/bin/sleep 5; /bin/rm -f /tmp/bztmp$$) 2>/dev/null &
#     /tmp/bztmp$$ ${1+"$@"}; res=$?
#   fi
# else
#   echo Cannot decompress $0; exit 1
# fi; exit $res

x=`basename $0`
if test $# = 0; then
  echo compress executables. original file foo is renamed to foo~
  echo usage: ${x} [-d] files...
  echo   "   -d  decompress the executables"
  exit 1
fi

tmp=bz$$
trap "rm -f $tmp; exit 1" 1 2 3 5 10 13 15

decomp=0
res=0
test "$x" = "unbzexe" && decomp=1
if test "x$1" = "x-d"; then
  decomp=1
  shift
fi

# echo hi > zfoo1$$
# echo hi > zfoo2$$
# if test -z "`(${CPMOD-cpmod} zfoo1$$ zfoo2$$) 2>&1`"; then
#   cpmod=${CPMOD-cpmod}
# fi
# rm -f zfoo[12]$$
cpmod="touch -r"

tail=""
IFS="${IFS= 	}"; saveifs="$IFS"; IFS="${IFS}:"
for dir in $PATH; do
  test -z "$dir" && dir=.
  if test -f $dir/tail; then
    tail="$dir/tail"
    break
  fi
done
IFS="$saveifs"
if test -z "$tail"; then
  echo cannot find tail
  exit 1
fi

for i do
  if test ! -f "$i" ; then
    echo ${x}: $i not a file
    res=1
    continue
  fi
  if test $decomp -eq 0; then
    if sed -e 1d -e 2q "$i" | grep "^skip=[0-9]*$" >/dev/null; then
      echo "${x}: $i is already bzexe'd"
      continue
    fi
  fi
  if ls -l "$i" | grep '^...[sS]' > /dev/null; then
    echo "${x}: $i has setuid permission, unchanged"
    continue
  fi
  if ls -l "$i" | grep '^......[sS]' > /dev/null; then
    echo "${x}: $i has setgid permission, unchanged"
    continue
  fi
  case "`basename $i`" in
  bzip2 | tail | chmod | ln | sleep | rm)
	echo "${x}: $i would depend on itself"; continue ;;
  esac
  if test -z "$cpmod"; then
    cp -p "$i" $tmp 2>/dev/null || cp "$i" $tmp
    if test -w $tmp 2>/dev/null; then
      writable=1
    else
      writable=0
      chmod u+w $tmp 2>/dev/null
    fi
  fi
  if test $decomp -eq 0; then
    if [ ! -e $tmp ] ;then
	# 20010801 RJVB: make a copy of the input file including its attributes to ensure
	# that the attributes on the compressed results are the same as on the original. NB:
	# this only works if file truncation by destructive output redirection preserves the
	# target's attributes (here by sed [options] > $tmp)
	    cp -p "$i" $tmp 2>/dev/null
    fi
    sed 1q $0 > $tmp
    cat >> $tmp << 'EOF1'
skip=24
prog="`echo $0 | /bin/sed 's|^.*/||'`"
if [ -x /tmp/$prog ] ;then
    trap '/bin/rm -f "/tmp/$prog"; exit $res' 0
    (/bin/sleep 5; /bin/rm -f "/tmp/$prog") 2>/dev/null &
	/tmp/$prog ${1+"$@"}; res=$?
else
EOF1
    sed "s|if TAIL |if $tail |" >> $tmp <<'EOF'
	if TAIL +$skip $0 | bzip2 -cd > /tmp/bztmp$$; then
	  /bin/chmod 755 /tmp/bztmp$$
	  if /bin/ln /tmp/bztmp$$ "/tmp/$prog" 2>/dev/null; then
	    trap '/bin/rm -f /tmp/bztmp$$ "/tmp/$prog"; exit $res' 0
	    (/bin/sleep 5; /bin/rm -f /tmp/bztmp$$ "/tmp/$prog") 2>/dev/null &
	    /tmp/"$prog" ${1+"$@"}; res=$?
	  else
	    trap '/bin/rm -f /tmp/bztmp$$; exit $res' 0
	    (/bin/sleep 5; /bin/rm -f /tmp/bztmp$$) 2>/dev/null &
	    /tmp/bztmp$$ ${1+"$@"}; res=$?
	  fi
	else
	  echo Cannot decompress $0; exit 1
	fi;
fi ; exit $res
EOF
    bzip2 -cv9 "$i" >> $tmp || {
      /bin/rm -f $tmp
      echo ${x}: compression not possible for $i, file unchanged.
      res=1
      continue
    }

  else
    # decompression
    skip=24
    if sed -e 1d -e 2q "$i" | grep "^skip=[0-9]*$" >/dev/null; then
      eval `sed -e 1d -e 2q "$i"`
    fi
    if tail +$skip "$i" | bzip2 -cd > $tmp; then
      :
    else
      echo ${x}: $i probably not in bzexe format, file unchanged.
      res=1
      continue
    fi
  fi
  rm -f "$i~"
  mv "$i" "$i~" || {
    echo ${x}: cannot backup $i as $i~
    rm -f $tmp
    res=1
    continue
  }
  mv $tmp "$i" || cp -p $tmp "$i" 2>/dev/null || cp $tmp "$i" || {
    echo ${x}: cannot create $i
    rm -f $tmp
    res=1
    continue
  }
  rm -f $tmp
  if test -n "$cpmod"; then
    $cpmod "$i~" "$i" 2>/dev/null
  elif test $writable -eq 0; then
    chmod u-w $i 2>/dev/null
  fi
done
exit $res