Provided by: mrtg_2.17.7-1ubuntu1_amd64 bug

NAME - Library for MRTG and support scripts


        use MRTG_lib;
        my ($configfile, @target_names, %globalcfg, %targetcfg);
        readcfg($configfile, \@target_names, \%globalcfg, \%targetcfg);
        my (@parsed_targets);
        cfgcheck(\@target_names, \%globalcfg, \%targetcfg, \@parsed_targets);


       MRTG_lib is part of MRTG, the Multi Router Traffic Grapher. It was separated from MRTG 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 funcions are there too.

           Type of OS: WIN, UNIX, VMS

           Slash in the current OS.

           Path separator in PATH variable

           "readcfg($file, \@targets, \%globalcfg, \%targetcfg [, $prefix, \%extrules])"

           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.

           The configuration file syntax is:

            globaloption: value
            targetoption[targetname]: value
            aprefix*extglobal: value
            aprefix*exttarget[target2]: value


            workdir: /var/stat/mrtg
            14all*columns: 2

           The global config hash has the structure

            $globalcfg{configoption} = 'value'

           The target config hash has the structure

            $targetcfg{configoption}{targetname} = 'value'

           See mrtg-reference for more information about the MRTG configuration syntax.

           "readcfg" 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 "14all" "readcfg" will
           check config lines that begin with "14all*", i.e. all lines like

            14all*columns: 2
            14all*graphsize[target3]: 500 200

           against the rules in %extrules. The format of this hash is:

            $extrules{option} = [sub{$_[0] =~ m/^\d+$/}, sub{"Error message for $_[0]"}]
            $extrules{option}[0] -> a test expression
            $extrules{option}[1] -> error message if test fails

           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 "$arg". The second part of the array is an
           error message to display when the test fails. The failed value can be integrated by
           using the variable "$arg".

           Config settings with an different prefix than the one given in the "readcfg" call are
           not checked but inserted into %globalcfg and %targetcfg.  Prefixed settings keep their
           prefix in the config hashes:

            $targetcfg{'14all*graphsize'}{'target3'} = '500 200'

           "cfgcheck(\@target_names, \%globalcfg, \%targetcfg, \@parsed_targets)"

           Checks the configuration read by "readcfg". Checks the values in the config for
           syntactical and/or semantical errors. Sets defaults for some options.  Parses the
           "target[...]" options and filles the array @parsed_targets ready for mrtg functions.

           The first three arguments are the same as for "readcfg". The fourth argument is an
           arrayref which will be filled with the parsed target defs.

           "cfgcheck" converts the values of target settings options, e.g.

            options[router1]: bits, growright

           to a hash:

            $targetcfg{'option'}{'bits'}{'router1'} = 1
            $targetcfg{'option'}{'growright'}{'router1'} = 1

           This is not done by "readcfg" so if you don't use "cfgcheck" you have to check the
           scalar variable $targetcfg{'option'}{'router1'} (MRTG allows options to be separated
           by space or ',').


           Checks that the pathname does not contain double path separators and ends with a path
           separator. It uses $MRTG_lib::SL as path separator which will be / or \ depending on
           the OS.

           "log2rrd ($router,\%globalcfg,\%targetcfg)"

           Convert log file to rrd format. Needs rrdtool.


           Returns the time given in the argument as a nicely formated date string.  The argument
           has to be in UNIX time format (seconds since 1970-1-1).


           Return a string representing the current time.


           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.


           Returns the time given in the argument formatted suitable for HTTP Expire-Headers.


           Creates a pid file for the mrtg daemon


           Puts the running program into background, detaching it from the terminal.

           "populatecache(\%confcache, $host, $reread, $snmpoptshash)"

           Reads the SNMP variables ifDescr, ipAdEntIfIndex, ifPhysAddress, ifName from the host
           and stores the values in %confcache as follows:

            $confcache{$host}{'Descr'}{ifDescr}{oid} = (ifDescr or 'Dup')
            $confcache{$host}{'IP'}{ipAdEntIfIndex}{oid} = (ipAdEntIfIndex or 'Dup')
            $confcache{$host}{'Eth'}{ifPhysAddress}{oid} = (ifPhysAddress or 'Dup')
            $confcache{$host}{'Name'}{ifName}{oid} = (ifName or 'Dup')
            $confcache{$host}{'Type'}{ifType}{oid} = (ifType or 'Dup')

           The value (at the right side of =) is 'Dup' if a value was retrieved muliple times,
           the retrieved value else.

           "my $confcache = readconfcache($file)"

           Preload the confcache from a file.


           Store the current confcache into a file.


           Store the current confcache into a file.




           "debug($type, $message)"

           Prints the message on STDERR if debugging is enabled for type type.  A debug type is
           enabled if type is in array @main::DEBUG.


       Rainer Bawidamann <>

       (This Manpage)