Sys::Utmp - Object(ish) Interface to UTMP files.

  use Sys::Utmp;

  my $utmp = Sys::Utmp->new();

  while ( my $utent =  $utmp->getutent() )
  {
     if ( $utent->user_process )
     {
        print $utent->ut_user,"\n";
     }
   }

   $utmp->endutent;

Sys::Utmp provides a vaguely object oriented interface to the Unix user accounting file ( usually /etc/utmp ). Whilst it would prefer to use the getutent() function from the systems C libraries it will attempt to provide its own if they are missing.

This may not be the module that you are looking for - there is a User::Utmp which provides a different procedural interface and may well be more complete for your purposes.

new

The constructor of the class. Arguments may be provided in Key => Value pairs : it currently takes one argument 'Filename' which will set the file which is to be used in place of that defined in _PATH_UTMP.

getutent

Iterates of the records in the utmp file returning a Sys::Utmp::Utent object for each record in turn - the methods that are available on these objects are descrived below in 'PER RECORD METHODS'

setutent

Rewinds the file pointer on the utmp filehandle so repeated searches can be done.

endutent

Closes the file handle on the utmp file.

utmpname SCALAR filename

Sets the file that will be used in place of that defined in _PATH_UTMP. It is not defined what will happen if this is done between two calls to getutent() - it is recommended that endutent() is called first.

As mentioned above the getutent method returns an object of the type Sys::Utmp::Utent which provides methods for accessing the fields in the utmp record. There are also methods for determining the type of the record.

The access methods relate to the common names for the members of the C struct utent - those provided are the superset from the Gnu implementation and may not be available on all systems: where they are not they will return the empty string.

ut_user

Returns the use this record was created for if this is a record for a user process. Some systems may return other information depending on the record type. If no user was set this will be the empty string.

ut_id

The identifier for this record - it might be the inittab tag or some other system dependent value.

ut_line

For user process records this will be the name of the terminalor line that the user is connected on.

ut_pid

The process ID of the process that created this record.

ut_type

The type of the record this will have a value corresponding to one of the constants (not all of these may be available on all systems and there may well be others which should be described in the getutent manpage or in /usr/include/utmp.h ) :

ACCOUNTING - record was created for system accounting purposes.

BOOT_TIME - the record was created at boot time.

DEAD_PROCESS - The process that created this record has terminated.

EMPTY - record probably contains no other useful information.

INIT_PROCESS - this is a record for process created by init.

LOGIN_PROCESS - this record was created for a login process (e.g. getty).

NEW_TIME - record created when the system time has been set.

OLD_TIME - record recording the old tme when the system time has been set.

RUN_LVL - records the time at which the current run level was started.

USER_PROCESS - record created for a user process (e.g. a login )

for convenience Sys::Utmp::Utent provides methods which are lower case versions of the constant names which return true if the record is of that type.

ut_host

On systems which support this the method will return the hostname of the host for which the process that created the record was started - for example for a telnet login. If taint checking has been turned on (with the -T switch to perl ) then this value will be tainted as it is possible that a remote user will be in control of the DNS for the machine they have logged in from. ( see perlsec for more on tainting )

ut_time

The time in epoch seconds wt which the record was created.

No methods or constants are exported by default.

These constants are exportable under the tag ':constants':

     ACCOUNTING
     BOOT_TIME
     DEAD_PROCESS
     EMPTY
     INIT_PROCESS
     LOGIN_PROCESS
     NEW_TIME
     OLD_TIME
     RUN_LVL
     USER_PROCESS

BUGS

Probably. This module has been tested on Linux, Solaris, FreeBSD ,SCO Openserver and SCO UnixWare and found to work on those platforms. If you have difficulty building the module or it doesnt behave as expected then please contact the author including if appropriate your /usr/include/utmp.h

Jonathan Stowe, <Jonathan.Stowe@netscalibur.co.uk>

This Software is Copyright Netscalibur UK 2001.

This Software is published as-is with no warranty express or implied.

This is free software and can be distributed under the same terms as Perl itself.

perl.