Mailing-List: contact cygwin-help AT cygwin DOT com; run by ezmlm
List-Subscribe: <mailto:cygwin-subscribe AT cygwin DOT com>
List-Archive: <http://sources.redhat.com/ml/cygwin/>
List-Post: <mailto:cygwin AT cygwin DOT com>
List-Help: <mailto:cygwin-help AT cygwin DOT com>, <http://sources.redhat.com/ml/#faqs>
Sender: cygwin-owner AT cygwin DOT com
Mail-Followup-To: cygwin AT cygwin DOT com
Delivered-To: mailing list cygwin AT cygwin DOT com
Date: Tue, 24 Feb 2004 10:47:03 -0500
From: Rick F Nicholson <sz8hb0 AT eng DOT delcoelect DOT com>
To: cygwin AT cygwin DOT com
Subject: Bugs: perl-libwin32-0.191-1 (Win32::Pipe->Connect) and using perl-5.8.2 open() to open an existing Win32 named pipe
Message-ID: <20040224154702.GA9385@ic.delcoelect.com>
Mime-Version: 1.0
Content-Type: multipart/mixed; boundary="nFreZHaLTZJo0R7j"
Content-Disposition: inline
User-Agent: Mutt/1.4.1i
X-Spam-Status: No, hits=-14.8 required=4.5 tests=BAYES_00,DELCO_LOCAL_SENDER, FROM_HAS_MIXED_NUMS autolearn=ham version=2.60
X-Spam-Checker-Version: SpamAssassin 2.60 (1.212-2003-09-23-exp) on koktsv73.delcoelect.com

--nFreZHaLTZJo0R7j
Content-Type: text/plain; charset=us-ascii
Content-Disposition: inline

I am currently writing an application that uses win32 named pipes to
communicate. The random length records being sent dictated opening
a file handle to the named pipe on the client and then using read()
to access the record. After noticing that libwin32-0.191 had been ported
to cygwin, I tried  a perl named pipe server and client that I had written
for debugging the app on ActiveState Perl-5.8.2. I noticed the following:

Win32::Pipe-Connect() is either non-blocking, doesn't get passed the timeout
value when the pipe is created or has a very low timeout value. This could
also be an interpretation problem. The behavior I had expected was that when
no client is connected, the Win32::Pipe-Connect() would wait for a client
to connect until a timeout occurs. The behavior I got was that Win32::Pipe->
Connect() returns immediately with "True" if a client is connected and "False"
if one has not.

Perl open() on the client side doesn't seem to understand using UNC to open
an existing named pipe. For example if I do the following:
open(PIPE, "<", "\\\\.\\pipe\\my named pipe"); I get an error
message:  "Mount device busy."  After trying to use open() to connect to the
named pipe, No other connections are possible. It would appear that open
is interpreting "\\\\.\\pipe\\my named pipe" as a mount request.

A perl script illustrating the problem is attached. Vital statistics are:
    Cygwin DLL version info:
        DLL version: 1.5.7
        DLL epoch: 19
        DLL bad signal mask: 19005
        DLL old termios: 5
        DLL malloc env: 28
        API major: 0
        API minor: 109
        Shared data: 3
        DLL identifier: cygwin1
        Mount registry: 2
        Cygnus registry name: Cygnus Solutions
        Cygwin registry name: Cygwin
        Program options name: Program Options
        Cygwin mount registry name: mounts v2
        Cygdrive flags: cygdrive flags
        Cygdrive prefix: cygdrive prefix
        Cygdrive default prefix: 
        Build date: Fri Jan 30 19:32:04 EST 2004
        CVS tag: cr-0x9e
        Shared id: cygwin1S3

and

perl                    5.8.2-1            
perl-libwin32           0.191-1            

Thanks in advance

--nFreZHaLTZJo0R7j
Content-Type: application/x-perl
Content-Disposition: attachment; filename="pipe_as_read_fh.pl"
Content-Transfer-Encoding: quoted-printable

#!/usr/bin/perl=0D
=0D
use Win32::Pipe;=0D
use Sys::Hostname;=0D
my $PipeName =3D "My Named Pipe";=0D
=0D
$| =3D 1; # Set output buffering to AUTO_FLUSH=0D
=0D
print "Spawning server and client\n" ;=0D
=0D
 SPAWN: {=0D
     my $pid;=0D
     print "Preparing to fork\n" ;=0D
     =0D
     if($pid=3Dfork()) {=0D
	 print "Spawning server\n" if defined ($DEBUG);=0D
	 =0D
	 np_server() ;=0D
=0D
     } elsif (defined($pid)) {=0D
	 print "Spawning client\n" if defined ($DEBUG);=0D
	 =0D
	 np_client() ;=0D
=0D
     } elsif ($! =3D~ /No more process/) {=0D
	 sleep 5;=0D
	 print "Respawning\n" ;=0D
	 redo SPAWN;=0D
     } else {=0D
	 die "Can't fork: $!\n";=0D
     }=0D
 }=0D
=0D
sub np_server {=0D
=0D
    my $Pipe_Error ;=0D
    my $Client_Disconnected;=0D
    my $Pipe_Connect_Status;=0D
    my $Test_Done ; =0D
    my $In;=0D
=0D
    print "NP Server: Creating pipe \"$PipeName\".\n";=0D
    =0D
=0D
    if( ($Pipe =3D new Win32::Pipe( $PipeName, NMPWAIT_WAIT_FOREVER, PIPE_T=
YPE_BYTE | PIPE_READMODE_BYTE | PIPE_WAIT))  )=0D
    {=0D
	print "NP Server: Done creating pipe.\n";=0D
		=0D
	$User =3D  getlogin() ;=0D
	print "NP Server: Pipe opened by $User.\n";=0D
	$Pipe_Error =3D 0;=0D
	$Test_Done =3D 0;=0D
	while(!$Pipe_Error && !$Test_Done) {=0D
	    $Client_Disconnected =3D 0;=0D
	    print "NP Server: Waiting for client to connect\n";=0D
=0D
	    while(( $Pipe->Connect()) && !$Pipe_Error && !$Client_Disconnected && =
!$Test_Done) {=0D
		print "NP Server: Client connected\n";=0D
		my $Data =3D "Pipe writen by $User. Time on " . hostname() . " is: " . lo=
caltime() . "\n";=0D
		    =0D
		if (!$Pipe->Write( $Data )) {=0D
		    print "NP Server: Error writing pipe\n";=0D
		    $Pipe_Error =3D 1;=0D
		    next ;=0D
		}=0D
		if (!($In=3D$Pipe->Read())) {=0D
		    print "NP Server: Error reading pipe\n";=0D
		    $Pipe_Error =3D 1;=0D
		    next ;=0D
		}=0D
		$Client_Disconnected =3D 1 if ($In eq "DONE") ;=0D
		$Test_Done =3D 1 if ($In eq "FINIS") ;=0D
		print "NP Server: Test Done\n" if ($In eq "FINIS") ;=0D
=0D
		print "NP Server: Disconnecting...\n";=0D
		$Pipe->Disconnect();=0D
		$Pipe->Close() if ($Test_Done);=0D
 =0D
	    }=0D
=0D
	    print "NP Server: Client Disconnected\n" if ($Client_Disconnected);;	 =
   print "NP Server: Pipe Error -- $|\n" if ($Pipe_Error);=0D
	    print "NP Server: Test Done\n" if ($Test_Done);=0D
	    sleep 1;=0D
	}=0D
   }=0D
    else=0D
    {=0D
	print "\nNP Server: Could not create pipe Error: " . Win32::Pipe::Error . =
"\n";=0D
    }=0D
}=0D
=0D
sub np_client {=0D
    =0D
    my $FQNPipeName =3D "\\\\.\\pipe\\" . $PipeName;=0D
    print "NP Client: Connecting to $FQNPipeName via Win32::Pipe\n";=0D
    =0D
    if( $Pipe =3D new Win32::Pipe( $FQNPipeName ) )=0D
    {=0D
	print "NP Client: Pipe has been opened, read data from it...\n";=0D
	my $In =3D $Pipe->Read();=0D
	print "NP Client: Server sent the client -- $In\n";=0D
	print "NP Client: Closing the pipe\n";=0D
	$Pipe->Write("DONE");=0D
	$Pipe->Close();=0D
    }=0D
    else=0D
    {=0D
	print "NP Client: Error connecting: " .  $Win32::Pipe::Error  . "\n";=0D
    }=0D
    print "NP Client: Connecting to $FQNPipeName via open()\n";=0D
    =0D
    sleep 1;=0D
    if( open(PIPE, "+<", $FQNPipeName ) )=0D
    {=0D
	my $In;=0D
	print "NP Client: Pipe has been opened, reading data from it...\n";=0D
	=0D
	read PIPE,  $In, 70 ;=0D
	print "NP Client: Server sent the client -- $In\n";=0D
	print PIPE  "DONE", 4;=0D
=0D
	close(PIPE);=0D
    }=0D
    else=0D
    {=0D
	print "NP Client: Error connecting via open(): $!\n";=0D
    }=0D
    print "NP Client: Finishing the test\n";=0D
=0D
    if( $Pipe =3D new Win32::Pipe( $FQNPipeName ) )=0D
    {=0D
    print "NP Client: Finishing the test\n";=0D
=0D
    $Pipe->Write("FINIS");=0D
    $Pipe->Close();=0D
    }=0D
    else=0D
    {=0D
	print "NP Client: Error connecting: " .  $Win32::Pipe::Error . "\n";=0D
    }=0D
    print "NP Client: Test Done\n";=0D
=0D
}=0D


--nFreZHaLTZJo0R7j
Content-Type: text/plain; charset=us-ascii

--
Unsubscribe info:      http://cygwin.com/ml/#unsubscribe-simple
Problem reports:       http://cygwin.com/problems.html
Documentation:         http://cygwin.com/docs.html
FAQ:                   http://cygwin.com/faq/
--nFreZHaLTZJo0R7j--