Net::Server::Multiplex - how to safe close client connection?

ph0enix has asked for the wisdom of the Perl Monks concerning the following question:

Hi all
How can be closed client connection @ server side if server is based on Net::Server::Multiplex module? In my code I used

for $h ($mux->handles()) {
  if ($fhs->{$h}{object}{user}{_id} == $id) {
    $mux->remove($h);   # remove from multiplexer loop
    $mux->close($h);    # close handle
    last;
  }
}
[download]

to find handle of connection to be closed an close it. Sometimes this works ok, but sometimes it broke down whole server with message 'Use of uninitialized value in exists at /opt/perl-5.8.0_t/lib/site_perl/5.8.0/IO/Multiplex.pm line 596 (#1)'. IO::Multiplex contain

591:
592:        foreach my $fh (values %{$self->{_handles}}) {
593:            # Avoid creating a permanent empty hash ref for "$fh"
594:            # by attempting to access its {object} element
595:            # if it has already been closed.
596:            next unless exists $self->{_fhs}{$fh};
597:
[download]

$mux->remove($h) call shold remove entry for closed connection from this %{$self->{_handles}} hash. Is it a race condition? How to fix it?

Comment on Net::Server::Multiplex - how to safe close client connection? Select or Download Code

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Re: Net::Server::Multiplex - how to safe close client connection? by ph0enix (Friar) on Apr 29, 2004 at 14:51 UTC
It seems to be ok if shutdown is used instead of remove and close. `for $h ($mux->handles()) { if ($fhs->{$h}{object}{user}{_id} == $id) { $mux->shutdown($h, 2); last; } }` [download] One is not supposed to modify arrays while they are being iterated over. There was problem because freed value used in iteration in $mux->loop, so the perl saw freed value and segfault.	[reply] [d/l]


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