diff --git a/src/doc/mrtg-mailer.pod b/src/doc/mrtg-mailer.pod
new file mode 120000
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--- /dev/null
+++ b/src/doc/mrtg-mailer.pod
@@ -0,0 +1 @@
+../bin/mrtg-mailer
\ No newline at end of file
diff --git a/src/doc/mrtglib.3 b/src/doc/mrtglib.3
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+.\" ========================================================================
+.\"
+.IX Title "doc::mrtglib 3"
+.TH doc::mrtglib 3 "2022-01-18" "2.17.9" "mrtg"
+.\" For nroff, turn off justification.  Always turn off hyphenation; it makes
+.\" way too many mistakes in technical documents.
+.if n .ad l
+.nh
+.SH "NAME"
+MRTG_lib.pm \- Library for MRTG and support scripts
+.SH "SYNOPSIS"
+.IX Header "SYNOPSIS"
+.Vb 5
+\& use MRTG_lib;
+\& my ($configfile, @target_names, %globalcfg, %targetcfg);
+\& readcfg($configfile, \e@target_names, \e%globalcfg, \e%targetcfg);
+\& my (@parsed_targets);
+\& cfgcheck(\e@target_names, \e%globalcfg, \e%targetcfg, \e@parsed_targets);
+.Ve
+.SH "DESCRIPTION"
+.IX Header "DESCRIPTION"
+MRTG_lib is part of \s-1MRTG,\s0 the Multi Router Traffic Grapher. It was separated
+from \s-1MRTG\s0 to allow other programs to easily use the same config files. The
+main part of MRTG_lib is the config file parser but some other functions are
+there too.
+.ie n .IP "$MRTG_lib::OS" 4
+.el .IP "\f(CW$MRTG_lib::OS\fR" 4
+.IX Item "$MRTG_lib::OS"
+Type of \s-1OS: WIN, UNIX, VMS\s0
+.ie n .IP "$MRTG_lib::SL" 4
+.el .IP "\f(CW$MRTG_lib::SL\fR" 4
+.IX Item "$MRTG_lib::SL"
+\&\fISlash\fR in the current \s-1OS.\s0
+.ie n .IP "$MRTG_lib::PS" 4
+.el .IP "\f(CW$MRTG_lib::PS\fR" 4
+.IX Item "$MRTG_lib::PS"
+Path separator in \s-1PATH\s0 variable
+.ie n .IP """readcfg""" 4
+.el .IP "\f(CWreadcfg\fR" 4
+.IX Item "readcfg"
+\&\f(CW\*(C`readcfg($file, \e@targets, \e%globalcfg, \e%targetcfg [, $prefix, \e%extrules])\*(C'\fR
+.Sp
+Reads a config file, parses it and fills some arrays and hashes. The
+mandatory arguments are: the name of the config file, a ref to an array which
+will be filled with a list of the target names, a hashref for the global
+configuration, a hashref for the target configuration.
+.Sp
+The configuration file syntax is:
+.Sp
+.Vb 4
+\& globaloption: value
+\& targetoption[targetname]: value
+\& aprefix*extglobal: value
+\& aprefix*exttarget[target2]: value
+.Ve
+.Sp
+E.g.
+.Sp
+.Vb 3
+\& workdir: /var/stat/mrtg
+\& target[router1]: 2:public@router1.local.net
+\& 14all*columns: 2
+.Ve
+.Sp
+The global config hash has the structure
+.Sp
+.Vb 1
+\& $globalcfg{configoption} = \*(Aqvalue\*(Aq
+.Ve
+.Sp
+The target config hash has the structure
+.Sp
+.Vb 1
+\& $targetcfg{configoption}{targetname} = \*(Aqvalue\*(Aq
+.Ve
+.Sp
+See mrtg-reference for more information about the \s-1MRTG\s0 configuration syntax.
+.Sp
+\&\f(CW\*(C`readcfg\*(C'\fR can take two additional arguments to extend the config file
+syntax. This allows programs to put their configuration into the mrtg config
+file. The fifth argument is the prefix of the extension, the sixth argument
+is a hash with the checkrules for these extension settings. E.g. if the
+prefix is \*(L"14all\*(R" \f(CW\*(C`readcfg\*(C'\fR will check config lines that begin with
+\&\*(L"14all*\*(R", i.e. all lines like
+.Sp
+.Vb 2
+\& 14all*columns: 2
+\& 14all*graphsize[target3]: 500 200
+.Ve
+.Sp
+against the rules in \f(CW%extrules\fR. The format of this hash is:
+.Sp
+.Vb 4
+\& $extrules{option} = [sub{$_[0] =~ m/^\ed+$/}, sub{"Error message for $_[0]"}]
+\&     i.e.
+\& $extrules{option}[0] \-> a test expression
+\& $extrules{option}[1] \-> error message if test fails
+.Ve
+.Sp
+The first part of the array is a perl expression to test the value of the
+option. The test can access this value in the variable \*(L"$arg\*(R". The second
+part of the array is an error message to display when the test fails. The
+failed value can be integrated by using the variable \*(L"$arg\*(R".
+.Sp
+Config settings with an different prefix than the one given in the \f(CW\*(C`readcfg\*(C'\fR
+call are not checked but inserted into \fI\f(CI%globalcfg\fI\fR and \fI\f(CI%targetcfg\fI\fR.
+Prefixed settings keep their prefix in the config hashes:
+.Sp
+.Vb 1
+\& $targetcfg{\*(Aq14all*graphsize\*(Aq}{\*(Aqtarget3\*(Aq} = \*(Aq500 200\*(Aq
+.Ve
+.ie n .IP """cfgcheck""" 4
+.el .IP "\f(CWcfgcheck\fR" 4
+.IX Item "cfgcheck"
+\&\f(CW\*(C`cfgcheck(\e@target_names, \e%globalcfg, \e%targetcfg, \e@parsed_targets)\*(C'\fR
+.Sp
+Checks the configuration read by \f(CW\*(C`readcfg\*(C'\fR. Checks the values in the config
+for syntactical and/or semantical errors. Sets defaults for some options.
+Parses the \*(L"target[...]\*(R" options and files the array \f(CW@parsed_targets\fR ready
+for mrtg functions.
+.Sp
+The first three arguments are the same as for \f(CW\*(C`readcfg\*(C'\fR. The fourth argument
+is an arrayref which will be filled with the parsed target defs.
+.Sp
+\&\f(CW\*(C`cfgcheck\*(C'\fR converts the values of target settings \fIoptions\fR, e.g.
+.Sp
+.Vb 1
+\& options[router1]: bits, growright
+.Ve
+.Sp
+to a hash:
+.Sp
+.Vb 2
+\& $targetcfg{\*(Aqoption\*(Aq}{\*(Aqbits\*(Aq}{\*(Aqrouter1\*(Aq} = 1
+\& $targetcfg{\*(Aqoption\*(Aq}{\*(Aqgrowright\*(Aq}{\*(Aqrouter1\*(Aq} = 1
+.Ve
+.Sp
+This is not done by \f(CW\*(C`readcfg\*(C'\fR so if you don't use \f(CW\*(C`cfgcheck\*(C'\fR you have to
+check the scalar variable \fI\f(CI$targetcfg\fI{'option'}{'router1'}\fR (\s-1MRTG\s0 allows
+options to be separated by space or ',').
+.ie n .IP """ensureSL""" 4
+.el .IP "\f(CWensureSL\fR" 4
+.IX Item "ensureSL"
+\&\f(CW\*(C`ensureSL(\e$pathname)\*(C'\fR
+.Sp
+Checks that the \fIpathname\fR does not contain double path separators and ends
+with a path separator. It uses \f(CW$MRTG_lib::SL\fR as path separator which will be /
+or \e depending on the \s-1OS.\s0
+.ie n .IP """log2rrd""" 4
+.el .IP "\f(CWlog2rrd\fR" 4
+.IX Item "log2rrd"
+\&\f(CW\*(C`log2rrd ($router,\e%globalcfg,\e%targetcfg)\*(C'\fR
+.Sp
+Convert log file to rrd format. Needs rrdtool.
+.ie n .IP """datestr""" 4
+.el .IP "\f(CWdatestr\fR" 4
+.IX Item "datestr"
+\&\f(CW\*(C`datestr(time)\*(C'\fR
+.Sp
+Returns the time given in the argument as a nicely formatted date string.
+The argument has to be in \s-1UNIX\s0 time format (seconds since 1970\-1\-1).
+.ie n .IP """timestamp""" 4
+.el .IP "\f(CWtimestamp\fR" 4
+.IX Item "timestamp"
+\&\f(CW\*(C`timestamp()\*(C'\fR
+.Sp
+Return a string representing the current time.
+.ie n .IP """setup_loghandlers""" 4
+.el .IP "\f(CWsetup_loghandlers\fR" 4
+.IX Item "setup_loghandlers"
+\&\f(CW\*(C`setup_loghandlers(filename)\*(C'\fR
+.Sp
+Install signalhandlers for _\|_DIE_\|_ and _\|_WARN_\|_ making the errors
+go the the specified destination. If filename is 'eventlog'
+mrtg will log to the windows event logger.
+.ie n .IP """expistr""" 4
+.el .IP "\f(CWexpistr\fR" 4
+.IX Item "expistr"
+\&\f(CW\*(C`expistr(time)\*(C'\fR
+.Sp
+Returns the time given in the argument formatted suitable for \s-1HTTP\s0
+Expire-Headers.
+.ie n .IP """create_pid""" 4
+.el .IP "\f(CWcreate_pid\fR" 4
+.IX Item "create_pid"
+\&\f(CW\*(C`create_pid()\*(C'\fR
+.Sp
+Creates a pid file for the mrtg daemon
+.ie n .IP """demonize_me""" 4
+.el .IP "\f(CWdemonize_me\fR" 4
+.IX Item "demonize_me"
+\&\f(CW\*(C`demonize_me()\*(C'\fR
+.Sp
+Puts the running program into background, detaching it from the terminal.
+.ie n .IP """populatecache""" 4
+.el .IP "\f(CWpopulatecache\fR" 4
+.IX Item "populatecache"
+\&\f(CW\*(C`populatecache(\e%confcache, $host, $reread, $snmpoptshash)\*(C'\fR
+.Sp
+Reads the \s-1SNMP\s0 variables \fIifDescr\fR, \fIipAdEntIfIndex\fR, \fIifPhysAddress\fR, \fIifName\fR from
+the \fIhost\fR and stores the values in \fI\f(CI%confcache\fI\fR as follows:
+.Sp
+.Vb 5
+\& $confcache{$host}{\*(AqDescr\*(Aq}{ifDescr}{oid} = (ifDescr or \*(AqDup\*(Aq)
+\& $confcache{$host}{\*(AqIP\*(Aq}{ipAdEntIfIndex}{oid} = (ipAdEntIfIndex or \*(AqDup\*(Aq)
+\& $confcache{$host}{\*(AqEth\*(Aq}{ifPhysAddress}{oid} = (ifPhysAddress or \*(AqDup\*(Aq)
+\& $confcache{$host}{\*(AqName\*(Aq}{ifName}{oid} = (ifName or \*(AqDup\*(Aq)
+\& $confcache{$host}{\*(AqType\*(Aq}{ifType}{oid} = (ifType or \*(AqDup\*(Aq)
+.Ve
+.Sp
+The value (at the right side of =) is 'Dup' if a value was retrieved
+multiple times, the retrieved value else.
+.ie n .IP """readconfcache""" 4
+.el .IP "\f(CWreadconfcache\fR" 4
+.IX Item "readconfcache"
+\&\f(CW\*(C`my $confcache = readconfcache($file)\*(C'\fR
+.Sp
+Preload the confcache from a file.
+.ie n .IP """readfromconfcache""" 4
+.el .IP "\f(CWreadfromconfcache\fR" 4
+.IX Item "readfromconfcache"
+\&\f(CW\*(C`writeconfcache($confcache,$file)\*(C'\fR
+.Sp
+Store the current confcache into a file.
+.ie n .IP """writeconfcache""" 4
+.el .IP "\f(CWwriteconfcache\fR" 4
+.IX Item "writeconfcache"
+\&\f(CW\*(C`writeconfcache($confcache,$file)\*(C'\fR
+.Sp
+Store the current confcache into a file.
+.ie n .IP """storeincache""" 4
+.el .IP "\f(CWstoreincache\fR" 4
+.IX Item "storeincache"
+\&\f(CW\*(C`storeincache($confcache,$host,$method,$key,$value)\*(C'\fR
+.ie n .IP """readfromcache""" 4
+.el .IP "\f(CWreadfromcache\fR" 4
+.IX Item "readfromcache"
+\&\f(CW\*(C`readfromcache($confcache,$host,$method,$key)\*(C'\fR
+.ie n .IP """clearfromcache""" 4
+.el .IP "\f(CWclearfromcache\fR" 4
+.IX Item "clearfromcache"
+\&\f(CW\*(C`clearfromcache($confcache,$host)\*(C'\fR
+.ie n .IP """debug""" 4
+.el .IP "\f(CWdebug\fR" 4
+.IX Item "debug"
+\&\f(CW\*(C`debug($type, $message)\*(C'\fR
+.Sp
+Prints the \fImessage\fR on \s-1STDERR\s0 if debugging is enabled for type \fItype\fR.
+A debug type is enabled if \fItype\fR is in array \f(CW@main::DEBUG\fR.
+.SH "AUTHORS"
+.IX Header "AUTHORS"
+Rainer Bawidamann <Rainer.Bawidamann@rz.uni\-ulm.de>
+.PP
+(This Manpage)