MRTGLIB(1)                           mrtg                           MRTGLIB(1)

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 sep-
       arated 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,

           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 con-

           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 the reference manpage for more information about the MRTG con-
           figuration 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

            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

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

           "cfgcheck(\@target_names, \%globalcfg, \%targetcfg, \@parsed_tar-

           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

           "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 sepa-
           rator 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


           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


           Puts the running program into background, detaching it from the

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

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

            $confcache{$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.

           "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.

       Tobias Oetiker <>, Dave Rand <> and other
       contributors, mentioned in the file "CHANGES"

       Documentation by Rainer Bawidamann <>

       GNU General Public License

       MRTG_lib is  Copyright 2000 by Tobias Oetiker <> and
       Dave Rand <>.

3rd Berkeley Distribution           2.9.17                          MRTGLIB(1)