usr.bin/gzip/gzexe

   1 #!/bin/sh -
   2 #
   3 # $NetBSD: gzexe,v 1.2 2003/12/28 12:43:43 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@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