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|
#!/bin/sh -
#
# $OpenBSD: gzexe,v 1.4 2005/09/30 06:50:44 otto Exp $
#
# Copyright (c) 2003 Otto Moerbeek <otto@drijf.net>
#
# Permission to use, copy, modify, and distribute this software for any
# purpose with or without fee is hereby granted, provided that the above
# copyright notice and this permission notice appear in all copies.
#
# THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
# WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
# MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
# ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
# WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
# ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
# OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
#
# The number of lines plus one in the on-the-fly decompression script
lines=19
# A simple string to recognize already compressed files
magic="# compressed by gzexe"
# Write the decompression script to stdout
header () {
typeset prog tmp
# first section needs variable expansion, second not
cat <<- EOF
#!/bin/sh -
$magic
lines=$lines
EOF
cat <<- 'EOF'
prog=`/usr/bin/basename "$0"`
tmp=`/usr/bin/mktemp -d /tmp/gzexeXXXXXXXXXX` || {
/bin/echo "$prog: cannot create tmp dir"; exit 1
}
trap '/bin/rm -rf "$tmp"' 0
if /usr/bin/tail +$lines "$0" |
/usr/bin/gzip -dc > "$tmp/$prog" 2> /dev/null; then
/bin/chmod u+x "$tmp/$prog"
"$tmp/$prog" ${1+"$@"}
ret=$?
else
/bin/echo "$prog: cannot decompress $0"
ret=1
fi
exit $ret
EOF
}
# Test if a file is compressed by checking the magic line
compressed () {
test "X`sed -n 2p "$1" 2> /dev/null`" = "X$magic"
}
# Decompress a file
decompress () {
tmp=`mktemp /tmp/gzexeXXXXXXXXXX` || {
echo "$prog: cannot create tmp file"
return 1
}
if ! cp "$1" "$tmp"; then
echo "$prog: cannot copy $1 to $tmp"
rm -f "$tmp"
return 1
fi
if ! tail +$lines "$tmp" | gzip -vdc > "$1"; then
echo "$prog: cannot decompress $1"
cp "$tmp" "$1"
rm -f "$tmp"
return 1
fi
}
# Perform some sanity checks on the file
check () {
if test ! -e "$1"; then
echo "$prog: cannot compress non-existing file $1"
return 1
fi
if test ! -f "$1"; then
echo "$prog: cannot compress non-regular file $1"
return 1
fi
case `basename "$1"` in
sh | mktemp | rm | echo | tail | gzip | chmod | basename)
echo "$prog: cannot compress $1, I depend on it"
return 1
esac
if test ! -x "$1"; then
echo "$prog: cannot compress $1, it is not executable"
return 1
fi
if test -u "$1" -o -g "$1"; then
echo "$prog: cannot compress $1, it has an s bit set"
return 1
fi
# Build a list of files we should not compress.
# * files we need to decompress
CHECK_LIST="
/bin/chmod
/bin/echo
/bin/sh
/bin/rm
/usr/bin/basename
/usr/bin/gzip
/usr/bin/mktemp
/usr/bin/tail
"
# * files in /bin and /sbin (decompression fails if /usr/bin is not mounted)
# (You could skip these if /usr/bin is always mounted on the same mount point.)
CHECK_LIST="$CHECK_LIST
/bin/*
/sbin/*
"
# See if the program we are trying to compress is in the list.
# To avoid compressing hardlinked files (eg compress & gzip)
# we compare the device & inode.
PROG_STAT_INFO=`stat -f '%d %i' "$1"`
for CHECK in $CHECK_LIST; do
if test -f "$CHECK"; then
CHECK_STAT_INFO=`stat -f '%d %i' "$CHECK"`
if test "X$PROG_STAT_INFO" == "X$CHECK_STAT_INFO"; then
echo "$prog: cannot compress $1, it is the same file as $CHECK"
return 1
fi
fi
done
}
# Compress a file
compress () {
tmp=`mktemp /tmp/gzexeXXXXXXXXXX` || {
echo "$prog: cannot create tmp file"
return 1
}
if ! cp "$1" "$tmp"; then
echo "$prog: cannot copy $1 to $tmp"
rm -f "$tmp"
return 1
fi
if ! cp "$1" "$1"~; then
echo "$prog: cannot create backup copy $1~"
rm -f "$1"~ "$tmp"
return 1
fi
# Use cp to overwrite the existing file preserving mode and owner
# if possible. If the file is not writable, this will produce an
# error.
if header "$1" > "$tmp" && gzip -vc "$1" >> "$tmp"; then
if ! cp "$tmp" "$1"; then
echo "$prog: cannot copy $tmp to $1"
rm -f "$tmp"
return 1
fi
else
echo "$prog: cannot compress $1"
rm -f "$1"~ "$tmp"
return 1
fi
}
# Is the -d flag specified?
dflag=
# Return value
rc=0
if test "X$1" = X-d; then
dflag=1
shift
fi
prog=`basename "$0"`
USAGE="usage: $prog [-d] file ..."
if test $# -eq 0; then
echo $USAGE
exit 1
fi
while test $# -ne 0; do
if test $dflag; then
if ! compressed "$1"; then
echo "$prog: $1 is not compressed"
rc=1;
elif ! decompress "$1"; then
rc=$?
fi
else
if compressed "$1"; then
echo "$prog: $1 is already compressed"
rc=1;
elif ! check "$1" || ! compress "$1"; then
rc=$?
fi
fi
shift
done
exit $rc
|
