[Tcl-bugs] [ tcl-Bugs-219273 ] socket -async combined with fileevent is broken on the Mac

[<no...@so...>]

Bugs item #219273, was opened at 2000-10-25 22:09
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Category: 52. Macintosh
Group: : 8.0.5
Status: Open
Resolution: None
Priority: 5
Submitted By: Nobody/Anonymous (nobody)
>Assigned to: Daniel A. Steffen (das)
Summary: socket -async combined with fileevent is broken on the Mac

Initial Comment:
OriginalBugID: 1663 Bug
Version: 8.0.5
SubmitDate: '1999-03-30'
LastModified: '2000-04-14'
Severity: CRIT
Status: UnAssn
Submitter: pat
ChangedBy: hobbs
RelatedBugIDs: 1776
OS: Macintosh
OSVersion: 8.0 (PPC)
Machine: Power PC
FixedDate: '2000-10-25'
ClosedDate: '2000-10-25'


Name:
mo

ReproducibleScript:
    set server ftp.netscape.com
    set port   12345
    
    if {[catch {
      set sock [socket -async $server $port]
    } err]} {
      puts "socket -async connect error 1 \$err\"
    }
    
    # define file event callback
    
    proc firstWritable { sock } {
      # remove writable fileevent handler
      fileevent $sock writable {}
      
      #find out if the connection worked by testing the -peername
    
      if [catch {fconfigure $sock -peername} peerinfo] {
        close $sock
        puts "socket -async connect error 2 \$peerinfo\"
      } else {
        puts "socket -async connect worked"
      }
    }
    
    
    
    # set up file event on the socket so we know
    # when it connects (or fails to connect)
    
    fileevent $sock writable "firstWritable $sock"
    
    



ObservedBehavior:
    When this code is run under MacOS with Tcl 8.0.5 it will fail
    to run the fileevent callback in the case where the host
    is unreachable. This same code works perfectly under Unix.
    
    While this is bad, it gets even worse if you
    invoke the fconfigure command like this:
    
    fconfigure $sock
    
    Doing this will kill wish completely
    with an error dialog that says
    "error closing async connect socket"
    
    This is no way to recover from this!
    



DesiredBehavior:
    I need to be able to test to see if the async socket
    connect worked using the writable fileevent. There is
    simply no other way to check the status of the socket
    without doing a read on the socket and doing a read
    on the socket is not an option because the program
    can not block Tk events during a network operation.
    





    It looks like the problem is located here. I am not sure what the fix

    is but a panic in this case does not seem like the correct action.

    

    tcl8.0.5/mac/tclMacSock.c:734

    

        /*

         * If this socket is in the midddle on async connect we can just

         * abort the connect and release the stream right now.

         */

    

        if (statePtr->flags & TCP_ASYNC_CONNECT) {

            InitMacTCPParamBlock(&closePB, TCPClose);

            closePB.tcpStream = tcpStream;

            closePB.ioCompletion = NULL;

            err = PBControlSync((ParmBlkPtr) &closePB);

            if (err != noErr) {

                panic("error closing async connect socket");

            }

            statePtr->flags |= TCP_RELEASE;

    

    



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

Comment By: Daniel A. Steffen (das)
Date: 2001-08-24 10:30

Message:
Logged In: YES 
user_id=90580




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You can respond by visiting: 
http://sourceforge.net/tracker/?func=detail&atid=110894&aid=219273&group_id=10894