Quota extension module for Perl
-------------------------------

Author:    T. Zoerner (tomzo AT users.sourceforge.net)

Version:   1.8.2
Date:      October 2021
DLSIP-Code:Rcdfg
           - stable release
           - C compiler required for installation
           - support by developer
           - plain functions, no references used
           - licensed under the Perl Artistic License or
             (at your option) version 2 or later of the
             GNU General Public License
Location:  https://metacpan.org/pod/Quota
Repository:https://github.com/tomzox/Perl-Quota

Supported: SunOS 4.1.3,
           Solaris 2.4 - 2.10,
           HP-UX 9.0x & 10.10 & 10.20 & 11.00,
           IRIX 5.2 & 5.3 & 6.2 - 6.5,
           OSF/1 & Digital Unix 4,
           FreeBSD 3 - 12.1, OpenBSD 2.2 - 6.6 & NetBSD 5 - 9,
           Linux - kernel 2.0.30 - 4.15,
           AIX 4.1, 4.2 and 5.3.

           Standard file systems of the platforms listed above,
           NFS (Network file system) on all of the above,
           XFS on Linux and IRIX 6,
           AFS (Andrew File System) on many of the above (see INSTALL),
           VxFS (Veritas File System) on Solaris 2.

Documentation is in pod format at the end of Quota.pm,
installation hints are in a file named INSTALL inside this package.
See also CHANGES for a history of updates to this module.

-----------------------------------------------------------------------------
  THIS PACKAGE IS PROVIDED "AS IS" AND WITHOUT ANY EXPRESS OR
  IMPLIED WARRANTIES, INCLUDING, WITHOUT LIMITATION, THE IMPLIED
  WARRANTIES OF MERCHANTIBILITY AND FITNESS FOR A PARTICULAR PURPOSE.
-----------------------------------------------------------------------------


NAME
     Quota - Perl interface to file system quotas

SYNOPSIS
         use Quota;

         ($block_curr, $block_soft, $block_hard, $block_timelimit,
          $inode_curr, $inode_soft, $inode_hard, $inode_timelimit) =
         Quota::query($dev [,$uid [,kind]]);

         ($block_curr, $block_soft, $block_hard, $block_timelimit,
          $inode_curr, $inode_soft, $inode_hard, $inode_timelimit) =
         Quota::rpcquery($host, $path [,$uid [,kind]]);

         Quota::rpcpeer([$port [,$use_tcp [,timeout]]]);

         Quota::setqlim($dev, $uid, $block_soft, $block_hard,
                        $inode_soft, $inode_hard [,$tlo [,kind]]);

         Quota::sync([$dev]);

         $arg = Quota::getqcarg([$path]);

         Quota::setmntent();
         ($dev, $path, $type, $opts) = Quota::getmntent();
         Quota::endmntent();


DESCRIPTION
     The Quota module provides access to file system quotas.  The
     quotactl system call or ioctl is used to query or set quotas
     on the local host, or queries are submitted via RPC to a
     remote host.  Mount tables can be parsed with getmntent and
     paths can be translated to device files (or whatever the
     actual quotactl implementations needs as argument) of the
     according file system.

     Functions

     ($bc,$bs,$bh,$bt, $ic,$is,$ih,$it) = Quota::query($dev, $uid, $kind)
         Get current usage and quota limits for a given file
         system and user.  The user is specified by its numeric
         uid; defaults to the process' real uid.

         The type of $dev varies from system to system. It's the
         argument which is used by the quotactl implementation to
         address a specific file system. It may be the path of a
         device file (e.g. /dev/sd0a) or the path of the mount
         point or the quotas file at the top of the file system
         (e.g. /home.stand/quotas). However you do not have to
         worry about that; use Quota::getqcarg to automatically
         translate any path inside a file system to the required
         $dev argument.

         $dev may also be in the form of hostname:path, which has
         the module transparently query the given host via a
         remote procedure call (RPC). In case you have NFS (or
         similar network mounts), this type of argument may also
         be produced by Quota::getqcarg. Note: RPC queries
         require rquotad(1m) to be running on the target system.
         If the daemon or host are down, the timeout is 12
         seconds.

         In $bc and $ic the current usage in blocks and inodes is
         returned.  $bs and $is are the soft limits, $bh and $ih
         hard limits. If the soft limit is exceeded, writes by
         this user will fail for blocks or inodes after $bt or
         $it is reached. These times are expressed as usual, i.e.
         in elapsed seconds since 00:00 1/Jan/1970 GMT.

         Note: When the quota limits are not exceeded, the timestamps
         are meaningless and should be ignored. When hard and soft
         limits are zero, there is no limit for that user. On most
         systems Quota::query will return undef in that case and
         errno will be set to ESRCH.

         When $kind is given and set to 1, the value in $uid is taken
         as gid and group quotas are queried. Group quotas may not be
         supported across all platforms (e.g. Linux and other BSD
         based Unix variants, OSF/1 and AIX - check the quotactl(2)
         man page on your systems).

         When $kind is set to 2, project quotas are queried; this is
         currently only supported for XFS. When unsupported, this flag
         is ignored.

     Quota::setqlim($dev, $uid, $bs,$bh, $is,$ih, $tlo, $kind)
         Sets quota limits for the given user. Meanings of $dev,
         $uid, $bs, $bh, $is and $ih are the same as in
         Quota::query.

         For file systems exceeding 2 TB: To allow passing block or
         inode values larger or equal to 2^32 on 32-bit Perl versions,
         pass them either as strings or floating point.

         $tlo decides how the time limits are initialized:  0:
         The time limits are set to NOT STARTED, i.e. the time
         limits are not initialized until the first write attempt
         by this user.  This is the default.  1: The time limits
         are set to 7.0 days.  More alternatives (i.e. setting a
         specific time) aren't available in most implementations.

         When $kind is given and set to 1, $uid is taken as gid and
         group quota limits are set. This is not supported on all
         platforms (see above). When $kind is set to 2, project quotas
         are modified; this is currently only supported for XFS. When
         unsupported, this flag is ignored.

         Note: if you want to set the quota of a particular user
         to zero, i.e.  no write permission, you must not set all
         limits to zero, since that is equivalent to unlimited
         access. Instead set only the hard limit to 0 and the
         soft limit for example to 1.

         Note that you cannot set quotas via RPC.

     Quota::sync($dev)
         Have the kernel update the quota file on disk or all
         quota files if no argument given (the latter doesn't
         work on all systems, in particular on HP-UX 10.10).

         The main purpose of this function is to check if quota
         is enabled in the kernel and for a particular file
         system. Read the quotaon(1m) man page on how to enable
         quotas on a file system.

         Note: on some systems this function always returns a
         success indication, even on partitions which do not
         have quotas enabled (e.g. Linux).  This is not a bug
         in this module; it's a limitation in certain kernels.

     ($bc,$bs,$bh,$bt, $ic,$is,$ih,$it) =
         Quota::rpcquery($host,$path,$uid,$kind)

         This is equivalent to Quota::query("$host:$path",$uid,$kind),
         i.e.  query quota for a given user on a given remote
         host via RPC.  $path is the path of any file or
         directory inside the wanted file system on the remote
         host.

         Querying group quotas ($kind = 1) is only recently supported
         on some platforms (e.g. on Linux via "extended" quota RPC,
         i.e. quota RPC version 2) so it may fail due to lack of
         support either on client or server side, or both.

     Quota::rpcpeer($port,$use_tcp,timeout)
         Configure parameters for subsequent RPC queries; all
         parameters are optional.  By default the portmapper on
         the remote host is used (i.e. default port is 0,
         protocol is UDP)  The default timeout is 4 seconds.

     Quota::rpcauth($uid,$gid,$hostname)
        Configure authorization parameters for subsequent
        RPC queries; all parameters are optional. By default
        uid and gid are taken from owner of the process and
        hostname is the host name of current machine.

     $arg = Quota::getqcarg($path)
         Get the required $dev argument for Quota::query and
         Quota::setqlim for the file system you want to operate
         on. $path is any path of an existing file or directory
         inside that file system. The path argument is optional
         and defaults to the current working directory.

         The type of $dev varies between operating systems, i.e.
         different implementations of the quotactl functionality.
         Hence it's important for compatibility to always use
         this module function and not really pass a device file
         to Quota::query (as returned by Quota::getdev).  See
         also above at Quota::query

     $dev = Quota::getdev($path)
         Returns the device entry in the mount table for a
         particular file system, specified by any path of an
         existing file or directory inside it. $path defaults to
         the working directory. This device entry need not really
         be a device. For example on network mounts (NFS) it's
         "host:mountpath", with amd(1m) it may be something
         completely different.

         NEVER use this to produce a $dev argument for other
         functions of this module, since it's not compatible. On
         some systems quotactl does not work on devices but on
         the quotas file or some other kind of argument. Always
         use Quota::getqcarg.

     Quota::setmntent()
         Opens or resets the mount table. This is required before
         the first invocation of Quota::getmntent.

         Note: on some systems there is no equivalent function in
         the C library.  But you still have to call this module
         procedure for initialization of module-internal
         variables.

     ($dev, $path, $type, $opts) = Quota::getmntent()
         Returns the next entry in the system mount table. This
         table contains information about all currently mounted
         (local or remote) file systems.  The format and location
         of this table (e.g. /etc/mtab) vary from system to
         system. This function is provided as a compatible way to
         parse it. (On some systems, like OSF/1, this table isn't
         accessible as a file at all, i.e. only via
         Quota::getmntent).

     Quota::endmntent()
         Close the mount table. Should be called after the last
         use of Quota::getmntent to free possibly allocated file
         handles and memory.  Always returns undef.

     Quota::strerr()
         Translates $! to a quota-specific error text. You should
         always use this function to output error messages, since
         the normal messages don't always make sense for quota
         errors (e.g. ESRCH: No such process, here: No quota for
         this user)

         Note that this function only returns a defined result if
         you called a Quota command directly before which returned
         an error indication.

RETURN VALUES
     Functions that are supposed return lists or scalars, return
     undef upon errors. As usual $! contains the error code (see
     Quota::strerr).

     Quota::endmntent always returns undef.  All other functions
     return 0 upon success, non-zero integer otherwise.

EXAMPLES
     An example for each function can be found in the test script
     test.pl. See also the contrib directory, which contains
     some longer scripts, kindly donated by users of the module.

BUGS
     With remote quotas we have to rely on the remote system to
     state correctly which block size the quota values are
     referring to. Old versions of the Linux rpc.rquotad
     reported a block size of 4 kilobytes, which was wildly
     incorrect. For more info on this and other Linux bugs please
     see INSTALL.

AUTHORS
     This module was created 1995 by T. Zoerner
     (email: tomzo AT users.sourceforge.net)
     and since then continually improved and ported to
     many operating- and file-systems. Numerous people
     have contributed to this process; for a complete
     list of names please see the CHANGES document.

     The quota module was in the public domain 1995-2001. Since 2001
     it is licensed under both the Perl Artistic License and version 1
     or later of the GNU General Public License as published by the
     Free Software Foundation.  For a copy of these licenses see
     <http://www.opensource.org/licenses/>.  The respective authors
     of the source code are its owner in regard to copyright.

SEE ALSO
     perl(1), edquota(1m), quotactl(2) or quotactl(7I),
     mount(1m), mtab(4) or mnttab(4), quotaon(1m), setmntent(3),
     getmntent(3) or getmntinfo(3), endmntent(3), rpc(3),
     rquotad(1m).

