#------------------------------------------------------------------------------
# RCS-Id: "@(#)$RCS-Id: pod/v2/afsperlcm.pod 2e2ca60 Tue Apr 15 13:04:20 2014 +0200 Norbert E Gruener$"
#
# © 2001-2014 Norbert E. Gruener <nog@MPA-Garching.MPG.de>
#
# This is free software; you can redistribute it and/or modify it under
# the same terms as the Perl 5 programming language system itself.
#------------------------------------------------------------------------------

=head1 NAME

B<AFS::CM> - Module to administer the B<AFS Cache Manager>

=head1 SYNOPSIS

  use AFS::CM qw (
                  checkconn checkservers checkvolumes
                  cm_access flush flushcb flushvolume
                  getcacheparms getcellstatus
                  getcrypt getvolstats setcrypt
                  setcachesize setcellstatus
                 );

  my $ok = flushvolume('.');
  print "Return Code = $ok\n";

  $ok = checkvolumes;
  print "Return Code = $ok\n";

  $ok = cm_access($path);
  print "Return Code = $ok\n";

 ($max, $inuse) = getcacheparms;
  $ok = setcachesize(10000);

  my $crypt_flg = getcrypt;
  $ok = setcrypt('on');

=head1 DESCRIPTION

This module provides several functions to administer the B<AFS Cache
Manager>. It is used to customize the cache size. You can force the
update of cached data.  And you can determine if a client machine can
run SETUID programs.  Any function required must by explicitly listed
by the C<use> statement to be exported into the calling package.

Some of these functions have the optional argument FOLLOW.  FOLLOW
determines which file should be used should PATH be a symbolic link.  If
FOLLOW be set to 1, then the symbolic link is followed to its target.
If FOLLOW is set to 0, then the function applies to the symbolic link
itself.  If not specified FOLLOW defaults to 1.

=head1 COMPATIBILITY

B<This release does NOT support any features and interfaces
from version 1.>

=head1 EXPORTS

=head2 Standard Exports

none

=head2 Optional Exports

The following functions will be exported into your namespace if you
specifically ask that they be imported.

=over 4

=item B<$ok = checkconn;>

Checks the status of all the callers tokens held by the Cache Manager.
Returns success if the caller has tokens, and all those tokens are valid
(i.e, not expired).

=cut

# does not work properly ???

# =item B<$ok = checkservers(FAST [, CELL [, IP]]);>

# Reports whether certain AFS server machines are accessible from the
# local client machine.  If the FAST flag is set to 1, the Cache Manager
# does not probe any machines, but instead reports the results of the most
# recent previous probe.  If the CELL argument is included, only machines
# that are marked inaccessible and belong to the specified CELL are
# listed.  If IP (default 0) is set to 1 then IP addresses will be
# returned instead of hostnames.

=item B<$ok = checkvolumes;>

Forces the Cache Manager to update volume-related information.

=item B<$ok = cm_access(PATH [, PERMS [,FOLLOW]]);>

Returns 1 if caller has access with the given permissions PERMS (default
'read') to given PATH.

=item B<$ok = flush(PATH [, FOLLOW]);>

Forces the Cache Manager to discard PATH.

=item B<$ok = flushcb(PATH [, FOLLOW]);>

Forces the Cache Manager to flush only the callback for PATH.

=item B<$ok = flushvolume(PATH [, FOLLOW]);>

Forces the Cache Manager to discard all cached data from the volume
containing PATH.

=item B<($max, $inuse) = getcacheparms;>

Returns the current size of the cache and the amount being used.

=item B<$setuid = getcellstatus([CELL]);>

Determines whether the local Cache Manager allows SETUID programs to run
or not.  Returns 1 if SETUID programs are allowed for given CELL
(default local).

=item B<$crypt_flg = getcrypt;>

Gets the Cache Manager encryption flag.  This function is supported only
under OpenAFS.

=item B<$volinfo = getvolstats(PATH [, FOLLOW]);>

Returns information about the volume containing PATH.  The return
value is a reference to a hash table containing the values from the C
structure C<VolumeStatus>.  The hash values can be up to five minutes
old, because the Cache Manager polls the File Server for partition
information at that frequency.  The hash table has the following keys

    Blessed         BlocksInUse     InService
    MaxQuota        MinQuota        Motd
    Name            NeedsSalvage    OffMsg
    Online          ParentId        PartBlocksAvail
    PartMaxBlocks   Type            Vid

You can find an example how to print the entire content of the
returned hash reference in the C<examples/v2/cm> directory.

=item B<$ok = setcachesize(NUM);>

Sets the size of the disk cache. NUM is size in 1K byte blocks

=item B<$ok = setcellstatus(SETUID_ALLOWED [,CELL]);>

Enables or disables the local Cache Manager to run SETUID programs for
the given CELL (default local).

=item B<$ok = setcrypt(FLAG);>

Set the Cache Manager encryption flag to FLAG. Valid values are 'on' or
'off'.  This function is supported only under OpenAFS.

=back

=head1 CURRENT AUTHOR

Norbert E. Gruener E<lt>nog@MPA-Garching.MPG.deE<gt>

=head1 AUTHOR EMERITUS

Roland Schemers E<lt>schemers@slapshot.stanford.eduE<gt>

=head1 COPYRIGHT AND LICENSE

 Copyright (c) 2001-2010 Norbert E. Gruener <nog@MPA-Garching.MPG.de>.
 All rights reserved.

 Copyright (c) 1994 Board of Trustees, Leland Stanford Jr. University.
 All rights reserved.

Most of the explanations in this document are taken from the original
AFS documentation.

 AFS-3 Programmer's Reference:
 File Server/Cache Manager Interface
 Edward R. Zayas
 Copyright (c) 1991 Transarc Corporation.
 All rights reserved.

 IBM AFS Administration Reference
 Copyright (c) IBM Corporation 2000.
 All rights reserved.

This is free software; you can redistribute it and/or modify it under
the same terms as the Perl 5 programming language system itself.

=over 6

=item The original module is covered by the following copyright:

Copyright (c) 1994 Board of Trustees, Leland Stanford Jr. University

Redistribution and use in source and binary forms are permitted
provided that the above copyright notice and this paragraph are
duplicated in all such forms and that any documentation,
advertising materials, and other materials related to such
distribution and use acknowledge that the software was developed
by Stanford University.  The name of the University may not be used
to endorse or promote products derived from this software without
specific prior written permission.
THIS SOFTWARE IS PROVIDED ``AS IS'' AND WITHOUT ANY EXPRESS OR
IMPLIED WARRANTIES, INCLUDING, WITHOUT LIMITATION, THE IMPLIED
WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE.

=back

=head1 DOCUMENT VERSION

Revision $Rev: 1059 $