#------------------------------------------------------------------------------
# RCS-Id: "@(#)$RCS-Id: pod/v2/afsperlacl.pod 2e2ca60 Tue Apr 15 13:04:20 2014 +0200 Norbert E Gruener$"
#
# © 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::ACL> - Class to handle the B<AFS Access Control Lists>

=head1 SYNOPSIS

  use AFS::ACL;

  my $acl = AFS::ACL->new({'foobar' => 'none'}, {'anyuser' => 'write'});
  $acl->set('rjs' => 'write');
  $acl->nset('opusl' => 'write');
  $acl->remove('rjsnfs' => 'write');
  $acl->clear;

  foreach my $user ($acl->get_users) {
      print " $user ", $acl->get_rights($user), "\n";
  }

  foreach my $user ($acl->nget_users) {
      print " $user ", $acl->nget_rights($user), "\n";
  }

  my $ok = $acl->apply('/afs/mpa/home/guest');

  my $copy   = $acl->copy;
  my $rights = AFS::ACL->crights('read');

  my $new_acl = AFS::ACL->retrieve('/afs/mpa/home/nog');
  $ok = $new_acl->modifyacl('/afs/mpa/home/guest');

=head1 DESCRIPTION

This class provides methods to handle the B<AFS Access Control Lists>
(ACL).  It is used to create, modify, delete, and reset ACL instances.
It has methods to retrieve and to set the ACL list for directories and
its files.

These methods 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 method 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 METHODS

=over 4

=item B<CONSTRUCTOR>

=item S< >

=item B<$acl = AFS::ACL-E<gt>new([\%POS [, \%NEG]]);>

Creates a new object of the class AFS::ACL.  The constructor takes two
optional arguments.  C<%POS> and C<%NEG> are lists of positive and
negative ACL entries given in the form of user-rights pairs, just like a
hash table.

=item B<COPY CONSTRUCTOR>

=item S< >

=item B<$new_acl = $acl-E<gt>copy;>

Returns a copy of an existing ACL object.

=item B<CLASS METHODS>

=item S< >

=item B<$acl = AFS::ACL-E<gt>retrieve(PATH [, FOLLOW]);>

Retrieves the ACL list for the given PATH and stores it in the object $acl.

=item B<$ok = AFS::ACL-E<gt>copyacl(FROMDIR, TODIR [, FOLLOW]);>

Copies the ACL list from a source directory FROMDIR to the specified destination
directory TODIR. The source directory''s ACL is unchanged.

=item B<$ok = AFS::ACL-E<gt>cleanacl(PATH [, FOLLOW]);>

Removes from the ACL list of the specified PATH any entry that
refers to a user or group that no longer has a Protection Database entry.

=item B<$crights = AFS::ACL-E<gt>crights(RIGHTS);>

Canonicalizes the RIGHTS string. Duplicate rights will be removed. It recognizes
the following special strings:
  read  => rl
  write => rlidwk
  all   => rlidwka
  mail  => lik

=item B<$flags = AFS::ACL-E<gt>ascii2rights(RIGHTS);>

Converts RIGHTS as expressed in a character string to its internal value
(an integer with the appropriate bits set).  Returns -1 if RIGHTS are
not valid (rlidwka, read, write, all, none) or returns the internal
value (int32 with bits set).

=item B<$rights = AFS::ACL-E<gt>rights2ascii(FLAGS);>

Converts the internal value FLAGS to its corresponding character string.

=item B<ATTRIBUTES ACCESS>

=item S< >

=item B<$rights = $acl-E<gt>get_rights(USER);>

=item B<$nrights = $acl-E<gt>nget_rights(USER);>

Returns the access rights for the given USER in the positive(-E<gt>get_rights) or
negative(-E<gt>nget_rights) ACL list.

=item B<$acl-E<gt>set(USER, RIGHTS);>

=item B<$acl-E<gt>nset(USER, RIGHTS);>

Adds the given USER and its access RIGHTS to the positive(-E<gt>set) or
negative(-E<gt>nset) ACL list.

=item B<$acl-E<gt>remove(USER);>

=item B<$acl-E<gt>nremove(USER);>

Removes the given USER and its access rights from the positive(-E<gt>remove) or
negative(-E<gt>nremove) ACL list.

=item B<$acl-E<gt>empty;>

Removes all users and their access rights from the positive and negative ACL list.

=item B<$acl-E<gt>clear;>

=item B<$acl-E<gt>nclear;>

Removes all users and their access rights from the positive(-E<gt>clear) or
negative(-E<gt>nclear) ACL list.

=item B<@users = $acl-E<gt>get_users;>

=item B<@nusers = $acl-E<gt>nget_users;>

Returns users from the positive(-E<gt>get_users) or negative(-E<gt>nget_users)
ACL list.

=item B<$pos = $acl-E<gt>length;>

=item B<$npos = $acl-E<gt>nlength;>

Returns the number of users in the positive(-E<gt>length)
or negative(-E<gt>nlength) ACL list.

=item B<$acl-E<gt>exists(USER);>

=item B<$acl-E<gt>nexists(USER);>

Returns 1 if the given USER exists in the positive(-E<gt>exists)
or negative(-E<gt>nexists) ACL list.

=item B<$acl-E<gt>is_clean>

Returns 1 if the ACL list is clean, or 0 when the ACL list needs
cleaning.  An ACL list needs cleaning if it contains entries
referencing nonexistant PTS entries, which are represented by a
numeric ID in the ACL instead of a name.

=item B<INSTANCE METHODS>

=item S< >

=item B<$acl-E<gt>add(NEWACL);>

Adds all entries of the ACL list NEWACL to the ACL list $acl.

=item B<$ok = $acl-E<gt>apply(PATH [, FOLLOW]);>

Sets the ACL list for the given PATH. This call replaces the existing ACL
list with the new ACL list $acl.

=item B<$ok = $acl-E<gt>modifyacl(PATH, [, FOLLOW]);>

Sets the ACL to the union of the given $acl list and the current ACL
of the PATH.  An access right of I<none> or an empty string will cause
an entry to be removed from the ACL.

=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) 2001-2011 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: 1056 $
