#!/usr/bin/perl
#
# vwho - Wrapper for who
#
# based on vps by Enrico Scholz

=head1 NAME 

vwho - show who is logged on all vserver guests

=head1 DESCRIPTION

B<vwho> runs L<who(1)> on every running vserver guest system and merges
the answers. 

Based on B<vps> by Enrico Scholz

=cut

if ($ARGV[0] eq "--help") {
   exec("who @ARGV");
   exit;
} 

foreach (@ARGV) {
    $headers = 1, last if (/^-H$/ || /^--heading$/);
}
$lockdir = "/var/run/vservers";

get_server_names();
$context=get_context("self");

if ($context == -1) {
   print "Can not find my security context. Is this a ctx kernel?\n";
   exit;
}
if ($context != 0) {
   print "not in context 0\n";
   exit;
} 
open WHO, "who @ARGV|"
	or print STDERR "failed to exec who: $!\n", goto VSERVER;
while (<WHO>) {
    if ($headers && /(USER|NAME)\s+LINE\s+(LOGIN-)?TIME\s+(COMMENT|FROM)/) {
        s/^/VSERVER         /;
    } else {
        s/^/MAIN            /;
    }
	print;
}
close WHO;

VSERVER:
foreach my $ctx (values %name) {
	open WHO, "/usr/sbin/vserver $ctx exec who @ARGV|"
		or print STDERR "failed to switch context to vserver $name{$ctx}\n",
           next VSERVER;
	while (<WHO>) {
        next
         if ($headers && /(USER|NAME)\s+LINE\s+(LOGIN-)?TIME\s+(COMMENT|FROM)/);
		s/^/sprintf('%-15s ', $ctx)/e;
		print;
	}
	close WHO;
}

exit;

sub get_context
{
   my $pid = $_[0];
   $pid =~ s/ //g;
   open STATUS, "/proc/$pid/status";
   while (<STATUS>)
   {
      chomp;
      if (/s_context: (\d+)/) {
         close STATUS;   
         return $1;
      }
   }
   close STATUS;
   return -1;
}

sub getcontextname {
   if (exists $name{$_[0]}) {
      return $name{$_[0]};
   }
   if    ($_[0] == 1) {
      return "ALL_PROCS";
   }
   elsif ($_[0] == 0) {
      return "MAIN";
   }
   return "UNKNOWN";
}


sub get_server_names {
    opendir LOCKDIR, "$lockdir";
    while ($file=readdir(LOCKDIR)) {
       if (-f "$lockdir/$file") {
          open FILE, "$lockdir/$file";
          $file =~ s/(.+)\.ctx/$1/;
          while (<FILE>) {
             if (/S_CONTEXT=(\d+)/) {
                $name{$1} = $file;
             }
          }
       }
    }
}

# vim: ts=4 sw=4 expandtab syn=perl