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 both zero, this means there is no limit for that user. (On some
platforms the query may fail with error code ESRCH in that case; most however still report valid
usage values.)
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 NOTSTARTED, 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 7.0days. 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-UX10.10).
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 2.4). 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. $path is the path of any file or directory inside the file system on
the remote host.
Querying group quotas ($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: Nosuchprocess, here: Noquotaforthisuser)
Note that this function only returns a defined result if you called a Quota command directly before
which returned an error indication.
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