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#!/usr/bin/perl -T
package VServer;
our $VERSION = '1.6';
use strict;
use warnings;
sub get_context_id_by_name($) {
my $vserver = shift;
if ($vserver =~ /^([-a-z0-9._]*)$/) {
$vserver = $1;
};
my $dir = "/etc/vservers/$vserver";
return unless -d $dir;
open(my $context, '<', "$dir/context") || return undef;
my $cid = undef;
while (<$context>) {
if ($_ =~ m/([0-9]*)/) {
$cid = $1;
last;
}
}
close $context;
return $cid;
}
sub get_context_id_by_dir($) {
my $dir = shift;
my $id = undef;
open(my $info, "<", "$dir/info") || return undef;
while (<$info>) {
if ($_ =~ m/^ID:\s*([0-9.]+)$/) {
$id = $1;
last;
}
}
close($info);
return $id;
}
sub get_proc_dir($) {
my $context = shift;
my $dir = "/proc/virtual/$context/";
return $dir if (-d $dir);
return undef;
}
sub get_config_dir($) {
my $context = shift;
my $dir = qx(/usr/sbin/vuname --xid $context --get context 2> /dev/null);
return undef unless ($? eq 0);
chomp($dir);
return $dir;
}
sub get_name($) {
my $context = shift;
my $dir = get_config_dir($context) || return undef;
my $name = undef;
open(my $file, "<", "$dir/name") || return undef;
while (<$file>) {
chomp($name = $_);
last;
}
close($file);
return $name;
}
sub get_loadavg($) {
my $id = shift;
my $dir = get_proc_dir($id) || return undef;
my @load = undef;
open(my $cvirt, "<", "$dir/cvirt") || return undef;
while (<$cvirt>) {
if ($_ =~ m/^loadavg:\s*([0-9.]+)\s*([0-9.]+)\s*([0-9.]+)$/) {
@load = ($1, $2, $3);
last;
}
}
close($cvirt);
return @load;
}
sub get_mem($) {
my $context = shift;
my $dir = get_proc_dir($context) || return undef;
my $ps = POSIX::sysconf(&POSIX::_SC_PAGESIZE) || return undef;
my @mem = undef;
open(my $limit, "<", "$dir/limit") || return undef;
while (<$limit>) {
if ($_ =~ m/^VM:\s*([0-9]+)\s/) {
$mem[0] = $1 * $ps;
}
elsif ($_ =~ m/RSS:\s*([0-9]+)\s/) {
$mem[1] = $1 * $ps;
}
elsif ($_ =~ m/ANON:\s*([0-9]+)\s/) {
$mem[2] = $1 * $ps;
}
elsif ($_ =~ m/VML:\s*([0-9]+)\s/) {
$mem[3] = $1 * $ps;
}
}
close($limit);
return @mem;
}
1;
__END__
=pod
=head1 NAME
VServer - little perl helpers for handling linux-vserver
=head1 SYNOPSIS
use VServer;
my $id = VServer::get_context_id("name");
=head1 DESCRIPTION
This module contains some functions for interfacing linux-vserver
with perl. It does not use the libvserver library, but reading files
in I</proc/virtual/> and I</etc/vservers/> and executing lightwight
external tools like I<vuname>.
=head2 Methods
=over 4
=item B<get_context_id_by_name($vserver_name)>
Returns the context id for a vserver given by its name. If an
invalid name is supplied or any other error occurs, B<undef>
is returned.
=item B<get_context_id_by_dir($proc_dir)>
Returns the context id for a vserver given by the path in the
I</proc/virtual/> tree. This could be done by parsing the path,
but the function uses the I<info> file and parsing the C<ID:> line.
If the I<info> file is not found or does not contain a line starting
with C<ID:>, B<undef> is returned.
=item B<get_proc_dir($context)>
Build the directory in C</proc/virtual/> for the given context id.
The directory is build with the following template:
I</proc/virtual/$context/>. If the resulting directory does not exist
(e.g. because the vserver is not running), B<undef> is returned.
=item B<get_config_dir($context)>
Returns the config directory for the given context id. This is done
by calling C</usr/sbin/vuname>. If any error occurs, B<undef> is
returned.
=item B<get_name($context)>
Returns the name of the vserver specified by the given context id.
This uses B<get_config_dir($context)> and reading the name file
inside the config directory. If any error occurs, B<undef> is
returned.
=item B<get_loadavg($context)>
Returns the three (load1, load5, load15) load values for the vserver
specified by the given context id. The functions reads the B<cvirt>
file inside the I</proc> directory of the vserver and parses the
loadavg values. The function returns the three values or B<undef>
if any error occurs.
=item B<get_mem($context)>
Return memory information for the vserver specified by the given
context id. The function read the B<limit> file inside the I</proc>
directory of the vserver, parses the memory information and
multiplies it with the pagesize. The function returns four values
in the following order I<virtual memory>, I<resident set size>,
I<anonymous memory> and I<virtual locked memory> or B<undef> if
any error occurs.
=back
=head1 AUTHORS
Alexander Sulfrian <alexander@sulfrian.net>
=cut
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