149 lines
3.2 KiB
Bash
Executable File
149 lines
3.2 KiB
Bash
Executable File
#!/bin/sh
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#
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# Copyright (C) 2001-2018 Graeme Walker <graeme_walker@users.sourceforge.net>
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#
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# This program is free software: you can redistribute it and/or modify
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# it under the terms of the GNU General Public License as published by
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# the Free Software Foundation, either version 3 of the License, or
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# (at your option) any later version.
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#
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# This program is distributed in the hope that it will be useful,
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# but WITHOUT ANY WARRANTY; without even the implied warranty of
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# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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# GNU General Public License for more details.
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#
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# You should have received a copy of the GNU General Public License
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# along with this program. If not, see <http://www.gnu.org/licenses/>.
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# ===
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#
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# emailrelay-process.sh
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#
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# An example "--filter" script for the E-MailRelay SMTP server which does
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# rot-13 masking.
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#
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awk="awk"
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tmp="/tmp/`basename $0`.$$.tmp"
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log="/tmp/`basename $0`.out"
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trap "rm -f \"${tmp}\" >/dev/null 2>&1 ; exit" 0 1 2 3 13 15
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###
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# ProcessContent()
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# Processes the content part of an RFC822 message. This
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# implementation does rot13 masking.
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#
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ProcessContent()
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{
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"${awk}" '
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BEGIN {
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map_upper = "ABCDEFGHIJKLMNOPQRSTUVWXYZ"
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map_lower = tolower(map_upper)
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in_header = 1
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}
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function rot( n , c , map )
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{
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return index(map,c) ? substr(map,((index(map,c)+n-1)%length(map))+1,1) : c
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}
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function rot_c( n , c )
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{
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return rot(n,rot(n,c,map_upper),map_lower)
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}
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function rot_s( n , string )
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{
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rot_s_result = ""
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for( i = 1 ; i <= length(string) ; i++ )
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rot_s_result = rot_s_result rot_c(n,substr(string,i,1))
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return rot_s_result
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}
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{
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is_blank = match($0,"^[[:space:]]*$")
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if( in_header && is_blank )
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in_header = 0
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if( in_header )
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print
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else
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print rot_s(13,$0)
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}
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'
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}
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###
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# Wrap()
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# Processes an RCF822 message so that the original content
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# appears as an attachment.
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#
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Wrap()
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{
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"${awk}" -v boundary="-----`basename $0`.$$" -v message="$@" '
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BEGIN {
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in_header = 1
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n = 1
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}
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{
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is_blank = match($0,"^[[:space:]]*$")
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if( in_header && is_blank )
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{
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printf( "Content-Type: multipart/mixed; boundary=\"%s\"\r\n" , boundary )
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printf( "\r\n" )
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printf( "\r\n" )
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printf( "--%s\r\n" , boundary )
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printf( "Content-Type: text/plain; charset=us-ascii\r\n" )
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printf( "\r\n" )
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printf( "%s\r\n" , message )
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printf( "\r\n" )
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printf( "--%s\r\n" , boundary )
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printf( "Content-Type: message/rfc822\r\n" )
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printf( "Content-Transfer-Encoding: 8bit\r\n" )
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printf( "Content-Description: encrypted message\r\n" )
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printf( "\r\n" )
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for( i = 1 ; i < n ; i++ )
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print header[i]
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}
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if( in_header && is_blank )
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in_header = 0
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if( in_header )
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{
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header[n++] = $0
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is_mime_content = match($0,"^Content-")
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is_continuation = match($0,"^[[:space:]][[:space:]]*[^[:space:]]")
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suppress = is_mime_content || (was_mime_content && is_continuation)
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was_mime_content = suppress
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if( ! suppress )
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print
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}
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else
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{
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print
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}
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}
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END {
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printf( "--%s--\r\n" , boundary )
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printf( "\r\n" )
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}
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'
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}
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Main()
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{
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cat "${1}" | ProcessContent | Wrap "The original message has been encrypted..." > "${tmp}"
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cp "${tmp}" "${1}"
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}
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debug="0"
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if test "${debug}" -eq 1
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then
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Main "$@" > "${log}" 2>&1
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else
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Main "$@"
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fi
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