I have written a server application in Perl, using the IO::Socket API, and my app crashes when the remote client (for instance, "telnet") is killed with a signal.

I create a listening socket, select() upon it for new logins, accept() them, and later loop calling select() on the new client socket.

Meanwhile, in client land, I invoke something like

telnet my_host 7777 

and after establishing the connection, from another shell on the same machine as the telnet process, I invoke:

    ps -aef | grep telnet
    kill -INT PID_of_that_telnet

The telnet process dies, and my server reports having read a few bytes (always the same bytes), and staggers on with a socket in a closed state.

DEBUG: Read 5 bytes from client 1
       from host '10.0.0.13' port '33008'.
       r_buf='ÿôÿý'

(The last byte seems to be \r or \b or somesuch.)

My problem is that, in Perl 5.005 my server would terminate, with error messages I wanted to paste in here, but cannot reproduce with Perl 5.6.0 now. :-(
These error messages appeared to be from a die() in socket.pm or somesuch, and I figured it to be a bug in socket or IO::Socket.

And under Perl 5.6.0, my code to handle client dropout is not catching the "killed by signal" case.

(I will admit that not getting a die() from within socket code, as I saw under Perl 5.005, is handier. Perhaps now this case can be tested for and handled.)

So, what I would like to know is:

1) How to trap this error like I do for ordinary logout (such as when I issue Control-], "quit", ENTER in telnet). In that case I get 0 bytes read from sysread(), and do socket close() and cleanup activities.

2) Can this be made to work under Perl 5.005? Or has a bug been fixed since then that I should know of?

Server code bits:
-----------------

### Create the listening socket:
$listen_socket = IO::Socket::INET->
        new('Listen'    => 5,
            'LocalAddr' => $server_host,
            'LocalPort' => $listen_port,
            'Proto'     => "TCP",
            );
# ...

### Handle login attempts:
my $listen_bit = $listen_socket->fileno();
if (vec($r_vec, $listen_bit, 1) == 1)
    {
    print "Login attempt on listening socket...\n";
    my $socket = $listen_socket->accept();
    # ...
    }
# ...

### Handle reading, and possible client dropout:
$bytes_read = $socket->sysread($r_buf, _POSIX_PIPE_BUF, 0);
# ...
elsif ($bytes_read == 0) { do_socket_close_and_cleaup(); }
# ...
[download]

----------------

Thanks for any advice,

--Sam <sglasby@penguinhosting.net>

Edit kudra, 2001-10-03 Took txt out of pre

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