gzip/gzexe

   1 #!/bin/sh -
   2 #
   3 # $NetBSD: gzexe,v 1.3 2004/05/01 08:22:41 wiz Exp $
   4 # $OpenBSD: gzexe,v 1.3 2003/08/05 18:22:17 deraadt Exp $
   5 #
   6 #-
   7 #  Copyright (c) 2003 Otto Moerbeek <otto@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 # $FreeBSD: src/usr.bin/gzip/gzexe,v 1.1 2007/01/26 10:19:07 delphij Exp $
  22
  23 # The number of lines plus one in the on-the-fly decompression script
  24 lines=19
  25
  26 # A simple string to recognize already compressed files
  27 magic="# compressed by gzexe"
  28
  29 # Write the decompression script to stdout
  30 header () {
  31         # first section needs variable expansion, second not
  32         cat <<- EOF
  33                 #!/bin/sh -
  34                 $magic
  35                 lines=$lines
  36         EOF
  37         cat <<- 'EOF'
  38                 prog=`/usr/bin/basename "$0"`
  39                 tmp=`/usr/bin/mktemp -d /tmp/gzexeXXXXXXXXXX` || {
  40                         /bin/echo "$prog: cannot create tmp dir"; exit 1
  41                 }
  42                 trap '/bin/rm -rf "$tmp"' 0
  43                 if /usr/bin/tail +$lines "$0" |
  44                     /usr/bin/gzip -dc > "$tmp/$prog" 2> /dev/null; then
  45                         /bin/chmod u+x "$tmp/$prog"
  46                         "$tmp/$prog" ${1+"$@"}
  47                         ret=$?
  48                 else
  49                         /bin/echo "$prog: cannot decompress $0"
  50                         ret=1
  51                 fi
  52                 exit $ret
  53         EOF
  54 }
  55
  56 # Test if a file is compressed by checking the magic line
  57 compressed () {
  58         test "X`sed -n 2p "$1" 2> /dev/null`" = "X$magic"
  59 }
  60
  61 # Decompress a file
  62 decompress () {
  63         tmp=`mktemp /tmp/gzexeXXXXXXXXXX` || {
  64                 echo "$prog: cannot create tmp file"
  65                 return 1
  66         }
  67         if ! cp "$1" "$tmp"; then
  68                 echo "$prog: cannot copy $1 to $tmp"
  69                 rm -f "$tmp"
  70                 return 1
  71         fi
  72         if ! tail +$lines "$tmp" | gzip -vdc > "$1"; then
  73                 echo "$prog: cannot decompress $1"
  74                 cp "$tmp" "$1"
  75                 rm -f "$tmp"
  76                 return 1
  77         fi
  78 }
  79
  80 # Perform some sanity checks on the file
  81 check () {
  82         if test ! -e "$1"; then
  83                 echo "$prog: cannot compress non-existing file $1"
  84                 return 1
  85         fi
  86
  87         if test ! -f "$1"; then
  88                 echo "$prog: cannot compress non-regular file $1"
  89                 return 1
  90         fi
  91
  92         case `basename "$1"` in
  93                 sh | mktemp | rm | echo | tail | gzip | chmod)
  94                         echo "$prog: cannot compress $1, I depend on it"
  95                         return 1
  96         esac
  97
  98         if test ! -x "$1"; then
  99                 echo "$prog: cannot compress $1, it is not executable"
 100                 return 1
 101         fi
 102
 103         if test -u "$1" -o -g "$1"; then
 104                 echo "$prog: cannot compress $1, it has an s bit set"
 105                 return 1
 106         fi
 107 }
 108
 109 # Compress a file
 110 compress () {
 111         tmp=`mktemp /tmp/gzexeXXXXXXXXXX` || {
 112                 echo "$prog: cannot create tmp file"
 113                 return 1
 114         }
 115         if ! cp "$1" "$tmp"; then
 116                 echo "$prog: cannot copy $1 to $tmp"
 117                 rm -f "$tmp"
 118                 return 1
 119         fi
 120         if ! cp "$1" "$1"~; then
 121                 echo "$prog: cannot create backup copy $1~"
 122                 rm -f "$1"~ "$tmp"
 123                 return 1
 124         fi
 125
 126         # Use cp to overwrite the existing file preserving mode and owner
 127         # if possible. If the file is not writable, this will produce an
 128         # error.
 129
 130         if header "$1" > "$tmp" && gzip -vc "$1" >> "$tmp"; then
 131                 if ! cp "$tmp" "$1"; then
 132                         echo "$prog: cannot copy $tmp to $1"
 133                         rm -f "$tmp"
 134                         return 1
 135                 fi
 136         else
 137                 echo "$prog: cannot compress $1"
 138                 rm -f "$1"~ "$tmp"
 139                 return 1
 140         fi
 141 }
 142
 143 # Is the -d flag specified?
 144 dflag=
 145
 146 # Return value
 147 rc=0
 148
 149 if test "X$1" = X-d; then
 150         dflag=1
 151         shift
 152 fi
 153
 154 prog=`basename "$0"`
 155 USAGE="usage: $prog [-d] file ..."
 156 if test $# -eq 0; then
 157         echo $USAGE
 158         exit 1
 159 fi
 160
 161 while test $# -ne 0; do
 162         if test $dflag; then
 163                 if ! compressed "$1"; then
 164                         echo "$prog: $1 is not compressed"
 165                         rc=1;
 166                 elif ! decompress "$1"; then
 167                         rc=$?
 168                 fi
 169         else
 170                 if compressed "$1"; then
 171                         echo "$prog: $1 is already compressed"
 172                         rc=1;
 173                 elif ! check "$1" || ! compress "$1"; then
 174                         rc=$?
 175                 fi
 176         fi
 177         shift
 178 done
 179 exit $rc