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      1 #!/bin/sh -
      2 #
      3 # $NetBSD: gzexe,v 1.3 2004/05/01 08:22:41 wiz Exp $
      4 #
      5 # $OpenBSD: gzexe,v 1.3 2003/08/05 18:22:17 deraadt Exp $
      6 #
      7 #  Copyright (c) 2003 Otto Moerbeek <otto (at] drijf.net>
      8 #
      9 #  Permission to use, copy, modify, and distribute this software for any
     10 #  purpose with or without fee is hereby granted, provided that the above
     11 #  copyright notice and this permission notice appear in all copies.
     12 #
     13 #  THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
     14 #  WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
     15 #  MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
     16 #  ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
     17 #  WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
     18 #  ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
     19 #  OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
     20 #
     21 
     22 # The number of lines plus one in the on-the-fly decompression script
     23 lines=19
     24 
     25 # A simple string to recognize already compressed files
     26 magic="# compressed by gzexe"
     27 
     28 # Write the decompression script to stdout
     29 header () {
     30 	# first section needs variable expansion, second not
     31 	cat <<- EOF
     32 		#!/bin/sh -
     33 		$magic
     34 		lines=$lines
     35 	EOF
     36 	cat <<- 'EOF'
     37 		prog=`/usr/bin/basename "$0"`
     38 		tmp=`/usr/bin/mktemp -d /tmp/gzexeXXXXXXXXXX` || {
     39 			/bin/echo "$prog: cannot create tmp dir"; exit 1
     40 		}
     41 		trap '/bin/rm -rf "$tmp"' 0
     42 		if /usr/bin/tail +$lines "$0" |
     43 		    /usr/bin/gzip -dc > "$tmp/$prog" 2> /dev/null; then
     44 			/bin/chmod u+x "$tmp/$prog"
     45 			"$tmp/$prog" ${1+"$@"}
     46 			ret=$?
     47 		else
     48 			/bin/echo "$prog: cannot decompress $0"
     49 			ret=1
     50 		fi
     51 		exit $ret
     52 	EOF
     53 }
     54 
     55 # Test if a file is compressed by checking the magic line
     56 compressed () {
     57 	test "X`sed -n 2p "$1" 2> /dev/null`" = "X$magic"
     58 }
     59 
     60 # Decompress a file
     61 decompress () {
     62 	tmp=`mktemp /tmp/gzexeXXXXXXXXXX` || {
     63 		echo "$prog: cannot create tmp file"
     64 		return 1
     65 	}
     66 	if ! cp "$1" "$tmp"; then
     67 		echo "$prog: cannot copy $1 to $tmp"
     68 		rm -f "$tmp"
     69 		return 1
     70 	fi
     71 	if ! tail +$lines "$tmp" | gzip -vdc > "$1"; then
     72 		echo "$prog: cannot decompress $1"
     73 		cp "$tmp" "$1"
     74 		rm -f "$tmp"
     75 		return 1
     76 	fi
     77 }
     78 
     79 # Perform some sanity checks on the file
     80 check () {
     81 	if test ! -e "$1"; then
     82 		echo "$prog: cannot compress non-existing file $1"
     83 		return 1
     84 	fi
     85 
     86 	if test ! -f "$1"; then
     87 		echo "$prog: cannot compress non-regular file $1"
     88 		return 1
     89 	fi
     90 
     91 	case `basename "$1"` in
     92 		sh | mktemp | rm | echo | tail | gzip | chmod)
     93 			echo "$prog: cannot compress $1, I depend on it"
     94 			return 1
     95 	esac
     96 
     97 	if test ! -x "$1"; then
     98 		echo "$prog: cannot compress $1, it is not executable"
     99 		return 1
    100 	fi
    101 
    102 	if test -u "$1" -o -g "$1"; then
    103 		echo "$prog: cannot compress $1, it has an s bit set"
    104 		return 1
    105 	fi
    106 }
    107 
    108 # Compress a file
    109 compress () {
    110 	tmp=`mktemp /tmp/gzexeXXXXXXXXXX` || {
    111 		echo "$prog: cannot create tmp file"
    112 		return 1
    113 	}
    114 	if ! cp "$1" "$tmp"; then
    115 		echo "$prog: cannot copy $1 to $tmp"
    116 		rm -f "$tmp"
    117 		return 1
    118 	fi
    119 	if ! cp "$1" "$1"~; then
    120 		echo "$prog: cannot create backup copy $1~"
    121 		rm -f "$1"~ "$tmp"
    122 		return 1
    123 	fi
    124 
    125 	# Use cp to overwrite the existing file preserving mode and owner
    126 	# if possible. If the file is not writable, this will produce an
    127 	# error.
    128 
    129 	if header "$1" > "$tmp" && gzip -vc "$1" >> "$tmp"; then
    130 		if ! cp "$tmp" "$1"; then
    131 			echo "$prog: cannot copy $tmp to $1"
    132 			rm -f "$tmp"
    133 			return 1
    134 		fi
    135 	else
    136 		echo "$prog: cannot compress $1"
    137 		rm -f "$1"~ "$tmp"
    138 		return 1
    139 	fi
    140 }
    141 
    142 # Is the -d flag specified?
    143 dflag=
    144 
    145 # Return value
    146 rc=0
    147 
    148 if test "X$1" = X-d; then
    149 	dflag=1
    150 	shift
    151 fi
    152 
    153 prog=`basename "$0"`
    154 USAGE="usage: $prog [-d] file ..."
    155 if test $# -eq 0; then
    156 	echo $USAGE
    157 	exit 1
    158 fi
    159 
    160 while test $# -ne 0; do
    161 	if test $dflag; then
    162 		if ! compressed "$1"; then
    163 			echo "$prog: $1 is not compressed"
    164 			rc=1;
    165 		elif ! decompress "$1"; then
    166 			rc=$?
    167 		fi
    168 	else
    169 		if compressed "$1"; then
    170 			echo "$prog: $1 is already compressed"
    171 			rc=1;
    172 		elif ! check "$1" || ! compress "$1"; then
    173 			rc=$?
    174 		fi
    175 	fi
    176 	shift
    177 done
    178 exit $rc
    179