Re: The mod_perl protocol handler sample code have some problem!

[Randy Kobes]

On Sun, 31 Jul 2005, Randy Kobes wrote:

If someone has a test linux box, could they see if things 
spin out of control if one uses an xterm to telnet in, and 
then closes the xterm? This probably won't happen, but it 
would be good to see if it's a Win32-specific problem.

Here's a scaled-down version of the problem - I used
commands with single letters, as my Win32 console sent a 
\r\n after each letter.
==========================================================
package Apache2::CS;
use strict;
use warnings FATAL => 'all';
use Apache2::Connection ();
use APR::Socket ();
use APR::Status ();
use Apache2::Const -compile => qw(OK DONE DECLINED);
use APR::Const -compile => qw(SO_NONBLOCK);

my @cmds = qw(d q);
my %commands = map { $_, \&{$_} } @cmds;

sub handler {
  my $c = shift;
  $| = 1;
  my $socket = $c->client_socket;
  $socket->opt_set(APR::Const::SO_NONBLOCK, 0);

  $socket->send("Welcome to " . __PACKAGE__ .
                "\r\nAvailable commands: @cmds\r\n");

  while (1) {
    my $cmd;
    next unless $cmd = getline($socket);
    last if $c->aborted;
    if (my $sub = $commands{$cmd}) {
      last unless $sub->($socket) == Apache2::Const::OK;
    }
    else {
      $socket->send("Commands: @cmds\r\n");
    }
  }
#  while ($socket->recv(my $buff, 1024)) {
#    last if $buff =~ /^[\r\n]+$/;
#    $socket->send("\r\n$buff\r\n");
#  }

  return Apache2::Const::OK;
}

sub getline {
  my $socket = shift;

  my $line;
  my $len = eval{ $socket->recv($line, 1024)};
  if ($@) {
    return Apache2::Const::DONE if APR::Status::is_ECONNABORTED($@);
  }
  return unless $line;
  $line =~ s/[\r\n]*$//;
  return $line;
}

sub d {
  my $socket = shift;
  $socket->send(scalar(localtime) . "\r\n");
  return Apache2::Const::OK;
}

sub q { Apache2::Const::DONE }

1;
__END__

# Apache configuration directives
#Listen 0.0.0.0:8541
#<VirtualHost _default_:8541>
#  PerlProcessConnectionHandler Apache2::CS
# 
#  <Location Apache2::CS>
#     Order Deny,Allow
#     Allow from all
#  </Location>
#</VirtualHost>

==================================================================

Then I try
   telnet localhost 8541

If one tries a bunch of commands (the 'd' works for me in 
getting the date), and then finally enters a 'q' for quit, 
the connection terminates normally. However, within the 
session, if one gives 'CTRL ]', one returns to the telnet 
prompt, and then as soon as one enters 'quit' at that 
prompt, the Apache process consumes 100% of the cpu.

If instead of the while(1){} loop within the handler
one uses the commented-out while() loop, no such problem
arises.

--
best regards,
randy