[Mldonkey-bugs] [bugs #11384] Source of Orphaned File Descriptor Bug

[Amorphous]

This mail is an automated notification from the bugs tracker
 of the project: mldonkey, a multi-networks file-sharing client.

/**************************************************************************/
[bugs #11384] Latest Modifications:

Changes by: 
                Amorphous <address@hidden>
'Date: 
                Wed 01/05/05 at 18:53 (GMT)

------------------ Additional Follow-up Comments ----------------------------
it's in the svn repository mentioned in another thread in that forum-group. i 
added a link to an archive of the source, schlumpf provided.






/**************************************************************************/
[bugs #11384] Full Item Snapshot:

URL: <http://savannah.nongnu.org/bugs/?func=detailitem&item_id=11384>
Project: mldonkey, a multi-networks file-sharing client
Submitted by: Rand Childs
On: Thu 12/23/04 at 15:46

Category:  Core
Severity:  5 - Average
Item Group:  Program malfunction
Resolution:  None
Privacy:  Public
Assigned to:  None
Status:  Open
Release:  None
Release:  2.5-22
Platform Version:  Mac OS X Jaguar
Binaries Origin:  CVS / Self compiled
CPU type:  PowerPC


Summary:  Source of Orphaned File Descriptor Bug

Original Submission:  On Mac OS X and I assume other systems there are two bugs 
in mlnet which together generate hundreds of orphaned file descriptors causing 
mlnet to eventually hang.  I worked with mlnet 2.5-22 source and ocaml 3.07-p12 
to debug the source of the problem:

I don't know the source code or OCAML well enough to suggest exactly why it is 
happening or the best way to fix it, but I have done enough debugging to figure 
out the cause of the probem. There are two issues: 

1. The first is in src/daemon/common/commonChat.ml in the routine 
send_paquet_to_mlchat. The Unix.connect fails with "Connection refused : 
connect" but the error is not trapped and the socket is not closed. Trapping 
the error and closing the socket fixes this one. 

2. The rest of the orphaned file descriptors is in 
src/utils/net/tcpServerSocket.ml in the routine tcp_handler. The Unix.accept 
fails with Exception tcp_handler: failed: Address family not supported by 
protocol family" but apparently has created a new socket which is never closed. 
If I trap the exception and issue the following "close t (Closed_for_error 
(Printexc2.to_string e));" I find that lsof only shows one orphaned socket 
after hours of running. I assume that issuing "close t" closes the original 
socket that is being listened to and this stop this Unix.accept from being 
called again. I don't know why it is getting this error unless perhaps the 
previous bind failed and that wasn't trapped, but maybe there is some other 
reason. 

So if a developer who knows the code and OCAML can fix these two problems and 
get the patches in the current release then that should solve the orhpaned file 
descriptor problem which causes mlnet to hang after running for some hours

Follow-up Comments
------------------


-------------------------------------------------------
Date: Wed 01/05/05 at 18:53         By: Amorphous <amorphous>
it's in the svn repository mentioned in another thread in that forum-group. i 
added a link to an archive of the source, schlumpf provided.

-------------------------------------------------------
Date: Wed 01/05/05 at 09:34         By:  <d-b>
I would like to try this but with what? I read the post at 
http://mldonkey.berlios.de/modules.php?name=Forums&file=viewtopic&t=3201&sid=6c52a2530f6046d72fdfbbb94c0c1d72
 and I have looked at the CVS-page but I don't know where the/which source to 
download - where is the 29ab-version?

-------------------------------------------------------
Date: Wed 01/05/05 at 09:30         By:  <d-b>
I would like to try this but with what? I read the post at 
http://mldonkey.berlios.de/modules.php?name=Forums&file=viewtopic&t=3201&sid=6c52a2530f6046d72fdfbbb94c0c1d72
 and I have looked at the CVS-page but I don't know where the/which source to 
download - where is the 29ab-version?

-------------------------------------------------------
Date: Wed 01/05/05 at 08:23         By: Amorphous <amorphous>
could you confirm if this is fixed with 2.5.29ab? see 
http://mldonkey.berlios.de/modules.php?name=Forums&file=viewtopic&t=3201&sid=6c52a2530f6046d72fdfbbb94c0c1d72

-------------------------------------------------------
Date: Thu 12/23/04 at 20:51         By: Rand Childs <shunga>
Programmer asleep at the switch :-).  I was wrong about some other software 
change.  Turns out tcp_handler does fail if changed as follows:

let tcp_handler t sock event =
  match event with 
  | CAN_READ
  | CAN_WRITE ->
      try 
        let s,id = Unix.accept (fd sock) in
        if !verbose_bandwidth > 1 then lprintf "[BW2 %6d] accept on %sn" 
(last_time ()) t.name;
        (match t.accept_control with
            None -> () | Some cc ->
              cc.nconnections_last_second <- cc.nconnections_last_second + 1);
        incr nconnections_last_second;
        t.event_handler t (CONNECTION (s,id))
      with  e ->
        lprintf "Exception tcp_handler: %sn" (Printexc2.to_string e);
        close t (Closed_for_error (Printexc2.to_string e)); 
        raise e
  | _ -> t.event_handler t (BASIC_EVENT event)

and it leaves one socket orphaned which I assume is "s".  I don't know how to 
get "s" down into the "with -> e" so that it can be closed and I don't know if 
I need to "close t" as is indicated in the code which at the moment is closing 
one of the server sockets that is being listened to., however, with this change 
"mlnet" has run for hours with only one orphaned socket.  This plus the 
commonChat change should get rid of the orphaned sockets.  I'll leave it up to 
the experts to figure out what is really going on and how to best fix it.

-------------------------------------------------------
Date: Thu 12/23/04 at 20:03         By: Rand Childs <shunga>
Well it would appear that the failure in tcp_handler was due to some other 
change that I must have made while attempting to debug this.  When I start over 
with a fresh copy of the source the handler doesn't fail and the file 
descriptors start building up.

Guess I have to go back and see if I can figure out what else it was that I 
changed.  :-(





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