Jonathan Stowe > Sys-Lastlog-1.7 > Sys::Lastlog

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Module Version: 1.7   Source  

NAME ^

Sys::Lastlog - Provide a moderately Object Oriented Interface to lastlog files on some Unix-like systems.

SYNOPSIS ^

  use Sys::Lastlog;

  my $ll = Sys::Lastlog->new();

  while(my $llent = $ll->getllent() )
  {
    print $llent->ll_line(),"\n";
  }

DESCRIPTION ^

The lastlog file provided on most Unix-like systems stores information about when each user on the system last logged in. The file is sequential and indexed on the UID (that is to say a user with UID 500 will have the 500th record in the file). Most systems do not provide a C API to access this file and programs such as 'lastlog' will provide their own methods of doing this.

This module provides an Object Oriented Perl API to access this file in order that programs like 'lastlog' can written in Perl (for example the 'plastlog' program in this distribution) or that programs can determine a users last login for their own purposes.

The module provides three methods for accessing lastlog sequentially, by UID or by login name. Each method returns an object of type Sys::Lastlog::Entry that itself provides methods for accessing the information for each record.

METHODS

new

The constructor of the class. Returns a blessed object that the other methods can be called on.

lastlog_path

Returns the full path to the lcoation of the lastlog file as defined by the operating system. Possibly only useful for diagnostic purposes currently.

getllent

This method will sequentially return each record in the lastlog each time it is called, returning a false value when there are no more records to return. Because the lastlog file is indexed on UID if there are gaps in the allocation of UIDs on a system will there will be as many empty records returned ( that is to say if for some reason there are no UIDs used between 200 and 500 this method will nonetheless return the 299 empty records .)

getlluid SCALAR $uid

This method will return a record for the $uid specified or a false value if the UID is out of range, it does however perform no check that the UID has actually been assigned it must simply be less than or equal to the maximum UID currently assigned on the system.

getllnam SCALAR $logname

This will return the record corresponding to the user name $logname or false if it is not a valid user name.

setllent

Set the file pointer on the lastlog file back to the beginning of the file for repeated iteration over the file using getllent() .

PER RECORD METHODS

These are the methods of the class Sys::Lastlog::Entry that give access to the information for each record.

uid

The UID that corresponds to this record.

ll_time

The time in epoch seconds of this users last login.

ll_line

The line (e.g. terminal ) that this user logged in via.

ll_host

The host from which this user logged in from or the empty string if it was a local login.

EXPORT

None at all

BUGS ^

Probably.

Some systems (notoriously Red Hat Linux) may mistakenly rotate the lastlog file periodically - there is no benefit in doing this as the file will only grow if new users are added to the system and in the authors opinion it is important to keep an accurate record of all users last logins however long ago for audit and security purposes. If you are on such a system and care about this you should disable the rotation of this file. On a Red Hat system this will involve editing /etc/logrotate.conf to remove the file from the rotation.

This should build on most systems given the notes in README but the author would appreciate being informed of any unusual systems where difficulty may be experienced.

The code is hosted at https://github.com/jonathanstowe/Sys-Lastlog so do feel free to fork and send pull requests

Occasionaly you may find that the entries in your /etc/passwd are out of order and this may give rise to test failures or other problems. You can either run setllent() if you find a missing entry or reorder your passwd file numerically. You may also need to reset the lastlog file by truncating the file and then logging in as the user with the highest UID.

You also almost certainly want to *not* try and get a lastlog entry for the user 'nobody' as this conventionally has a uid of 65534 and the lastlog file doesn't get that big.

It would probably be useful to set the path to the lastlog file from within the perl program. This is on the TODO list.

AUTHOR ^

Jonathan Stowe <jns@gellyfish.co.uk>

COPYRIGHT AND LICENSE ^

Copyright Jonathan Stowe 2001 - 2013.

This software comes with no warranty whatsoever.

This is free software and may be distributed and/or modified under the same terms as Perl itself.

SEE ALSO ^

perl.

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