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rearranging of ch04
author meillo@marmaro.de
date Wed, 10 Dec 2008 21:12:09 +0100
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1 \chapter{\masqmail's present and future} 1 \chapter{\masqmail's present and future}
2 2
3 \section{Existing features} 3 \section{Existing code base}
4 This overview regards \masqmail\ version 0.2.21, the state this document starts off. 4 Here regarded is version 0.2.21 of \masqmail. This is the last version released by \person{Oliver Kurth}, and the basis for my thesis.
5 5
6 \masqmail\ is an \MTA, therefor it accepts mail on the command line and via \SMTP. Mail queueing and alias expansion is supported. \masqmail\ is able to deliver mail to local mailboxes (in \name{mbox} or \name{maildir} format) or pass it to a \name{mail delivery agent} (like \name{procmail}). Mail destinated to remote locations is sent via \SMTP. Outgoing \SMTP\ connections feature \name{SMTP-Auth} and \name{SMTP-after-POP} authentication, but incoming \SMTP\ does not. 6 \subsubsection*{Features}
7 7
8 As \masqmail\ is focused on non-permanent Internet connections, online state can be queried by three methods: reading from a file, reading the output of a command, or by asking an \name{mserver}. Each method may return a string indicating one of the available routes being online, or returning nothing to indicate offline state. 8 \masqmail\ accepts mail on the command line and via \SMTP. Mail queueing and alias expansion is supported. \masqmail\ is able to deliver mail to local mailboxes (in \name{mbox} or \name{maildir} format) or pass it to a \name{mail delivery agent} (like \name{procmail}). Mail destinated to remote locations is sent using \SMTP.
9 9
10 Delivery to recipients on the local host or in local nets is done at once; delivery to recipients on the Internet is only done when being online, and queued otherwise. Each online route may have a different mail server to which mail is relayed. Return address headers are modified appropriate if wished. 10 Outgoing \SMTP\ connections feature \SMTP-\NAME{AUTH} and \SMTP-after-\NAME{POP} authentication, but incoming \SMTP\ does not.
11 %todo: what about SSL/TLS encryption?
11 12
12 Additional to the \mta\ job, \masqmail\ also offers mail retrieval services with being a \NAME{POP3} client. Thus it can fetch mail from remote locations, dependent on the active online route. 13 The \masqmail\ executable can be called under various names for sendmail-compatibility reasons. This is organized by symbolic links with different names pointing to the \masqmail\ executable. The \sendmail\ names are \path{/usr/lib/sendmail} and \path{/usr/sbin/sendmail} because many programs expect the \mta\ to be located there. Further more \sendmail\ supports calling it with a different name instead of supplying command line arguments. The best known of this shortcuts is \path{mailq}, which is equivilent to calling it with the argument \verb+-bq+. \masqmail\ recognizes the names \path{mailq}, \path{smtpd}, \path{mailrm}, \path{runq}, \path{rmail}, and \path{in.smtpd}. The first two are inspired by \sendmail. Not implemented is the name \path{newaliases} because \masqmail\ does not generate binary representations of the alias file.\footnote{A shell script located named \path{newaliases}, that invokes \texttt{masqmail -bi}, can provide the command to satisfy other software needing it.} \path{hoststat} and \path{purgestat} are missing for sendmail-compatibility.
14 %masqmail: mailq, mailrm, runq, rmail, smtpd/in.smtpd
15 %sendmail: hoststat, mailq, newaliases, purgestat, smtpd
16
17 Additional to the \mta\ job, \masqmail\ also offers mail retrieval services with being a \NAME{POP3} client. It can fetch mail from different remote locations, dependent on the active online route.
13 18
14 19
15 20
16 The \masqmail\ executable can be called under various names for \name{sendmail-compatibility} reasons. This is commonly organized by creating symbolic links with with different names to the \masqmail\ executable. These are \path{/usr/lib/sendmail} and \path{/usr/sbin/sendmail} because many programs expect a \mta\ to be located there. Further more \sendmail\ provides shortcuts by calling it with a different name instead of supplying command line arguments. The best known of it is \path{mailq}, which is equivilent to calling the \MTA\ with the argument \verb+-bq+. \masqmail\ reacts to the names \path{mailq}, \path{smtpd}, \path{mailrm}, \path{runq}, \path{rmail}, and \path{in.smtpd}. The last four are an addition to \sendmail. Not implemented is the name \path{newaliases} because it is not relevant to \masqmail. To provide the command nonetheless, one may write a shell script located at \path{/usr/bin/newaliases}, that simply invokes \verb+masqmail -bi+. 21 \subsubsection*{The code}
17 22
18 %masqmail: mailq, mailrm, runq, rmail, smtpd/in.smtpd 23 \masqmail\ is written in the C programming language. The program, as of version 0.2.21, consists of 34 source code and eight header files, containing about 9,000 lines of code\footnote{Measured with \name{sloccount} by David A.\ Wheeler.}. Additionally, it includes a \name{base64} implementation (about 300 lines) and \name{md5} code (about 150 lines). For systems that do not provide \name{libident}, this library is distributed as well (circa 600 lines); an available shared library however has higher precedence in linking.
19 %sendmail: hoststat, mailq, newaliases, purgestat, smtpd
20 24
21 \masqmail\ is written in the \NAME{C} programming language. The program, as of version 0.2.21, consists of 34 source code and eight header files, containing about 9,000 lines of code\footnote{Measured with \name{sloccount} by David A.\ Wheeler.}. Additionally, it includes a \name{base64} implementation (about 300 lines) and \name{md5} code (about 150 lines). For systems that do not provide \name{libident}, this library is distributed as well (circa 600 lines); an available shared library however has higher precedence in linking. 25 The only mandatory dependency is \name{glib}---a cross-platform software utility library, originated in the \NAME{GTK+} project. It provides safer replacements for many standard library functions. It also offers handy data containers, easy-to-use implementations of data structures, and much more.
22 26
23 The only mandatory dependency is \name{glib}---a cross-platform software utility library, originated in the \NAME{GTK+} project. It provides safer replacements for many standard library functions. (The unsafe \verb+sprintf()+ is one example.) Also it offers handy data containers, easy-to-use implementations of data structures, and much more.
24 27
25 With \masqmail\ comes the small tool \path{mservdetect}; it helps setting up a configuration that uses the \name{mserver} system to detect the online state. Two other binaries get compiled for testing purposes: \path{readtest} and \path{smtpsend}. All three programms use \masqmail\ source code; they only add a file with a \verb+main()+ function each. 28 With \masqmail\ comes the small tool \path{mservdetect}; it helps setting up a configuration that uses the \name{mserver} system to detect the online state. Two other binaries get compiled for testing purposes: \path{readtest} and \path{smtpsend}. All three programms use \masqmail\ source code; they only add a file with a \verb+main()+ function each.
26 29
27 \masqmail\ does not provide an interface for modules with additional functionality. There exists no add-on or module system. But the code is separated by function to the various source files, and some functional parts can be included or excluded by defining symbols. This means adding some argument (like \verb+--enable-maildir+) to the \verb+configure+ call. Thus the concerning code gets not removed by the preprocessor. 30
31 \masqmail\ does not provide an interface to plug in modules with additional functionality. There exists no add-on or module system. The code is only separated by function to the various source files. Some functional parts can be included or excluded by defining symbols. Adding maildir support at compile time, means giving the option \verb+--enable-maildir+ to the \path{configure} call. This preserves the concerning code to get removed by the preprocessor. Unfortunately the \verb+#ifdef+s are scattered through all the source, leading to a FIXME(holperig) code base.
28 32
29 33
30 34
31 35
32 36
33 \section{Discussion/Ideas} 37 \section{Directions to go}
38
39 << plans to get masqmail more popular again (if that is the goal) >> %FIXME
34 40
35 41
36 << plans to get masqmail more popular again (if that is the goal) >> %FIXME 42 \subsection{\masqmail\ in five years}
43
44 Now how could \masqmail\ be like in, say, five years?
45
46 << requirements >> %FIXME
47
48 << which parts to do >> %FIXME
49
50 << how to make masqmail future-safe >> %FIXME
51
52 << how to advertise masqmail >> %FIXME
53
54 << why is it worth to revive masqmail? >> %FIXME
55
56
57
58 << concrete decisions based on results of the last 2 chapters >> %FIXME
59
60
37 61
38 62
39 \subsection{Architecture} 63 \subsection{Architecture}
40 64
41 << architecture diagram >> 65 << architecture diagram >>
75 http://fanf.livejournal.com/70432.html %how not to design an mta - address verification 99 http://fanf.livejournal.com/70432.html %how not to design an mta - address verification
76 http://fanf.livejournal.com/72258.html %how not to design an mta - content scanning 100 http://fanf.livejournal.com/72258.html %how not to design an mta - content scanning
77 101
78 102
79 103
80 << concrete decisions based on results of the last 2 chapters >> %FIXME
81 104
82 105
83 106
84 107
85 108
86 109
87 \section{Directions to go}
88
89 \subsection{\masqmail\ in five years}
90 \label{sec:masqmail-in-5-years}
91 Now how could \masqmail\ be like in, say, five years?
92
93 << requirements >> %FIXME
94
95 << which parts to do >> %FIXME
96
97 << how to make masqmail future-safe >> %FIXME
98
99 << how to advertise masqmail >> %FIXME
100
101 << difference for free software >> %FIXME
102
103 << why is it worth to revive masqmail? >> %FIXME
104 110
105 111
106 112
107 113
108 114