MRTGLIB(1)                     mrtg                    MRTGLIB(1)



NAME
       MRTG_lib.pm - Library for MRTG and support scripts

SYNOPSIS
        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);

DESCRIPTION
       MRTG_lib is part of MRTG, the Multi Router Traffic Gra-
       pher. 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.

       $MRTG_lib::OS
           Type of OS: WIN, UNIX, VMS

       $MRTG_lib::SL
           Slash in the current OS.

       $MRTG_lib::PS
           Path separator in PATH variable

       "readcfg"
           "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

           E.g.

            workdir: /var/stat/mrtg
            target[router1]: 2:public@router1.local.net
            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]"}]
                i.e.
            $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"
           "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 "read-
           cfg". 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 $tar-
           getcfg{'option'}{'router1'} (MRTG allows options to be
           separated by space or ',').

       "ensureSL"
           "ensureSL(\$pathname)"

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

           Convert log file to rrd format. Needs rrdtool.

       "datestr"
           "datestr(time)"

           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).

       "timestamp"
           "timestamp()"

           Return a string representing the current time.

       "setup_loghandlers"
           "setup_loghandlers(filename)"

           Install signalhandlers for __DIE__ and __WARN__ making
           the errors go the the specified destination. If file-
           name is 'eventlog' mrtg will log to the windows event
           logger.

       "expistr"
           "expistr(time)"

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

       "create_pid"
           "create_pid()"

           Creates a pid file for the mrtg daemon

       "demonize_me"
           "demonize_me()"

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

       "populatecache"
           "populatecache(\%confcache, $host, $reread, $snmpopt-
           shash)"

           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.

       "readconfcache"
           "my $confcache = readconfcache($file)"

           Preload the confcache from a file.

       "writeconfcache"
           "writeconfcache($confcache,$file)"

           Store the current confcache into a file.

       "debug"
           "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.

AUTHORS
       Tobias Oetiker <tobi@oetiker.ch>, Dave Rand
       <dlr@bungi.com> and other contributors, mentioned in the
       file "CHANGES"

       Documentation by Rainer Bawidamann <Rainer.Baw-
       idamann@rz.uni-ulm.de>



2.10.13                     2004-01-19                 MRTGLIB(1)
