[twsocket] Threaded TWSocketServer derivation
Hello,
After a big fight with deadlocks and race conditions for one day my
threaded TWSocketServer derivation is now working stable.
(tested with Wilfrieds GPRS Client and other stressing clients)
But.. I have still a tiny problem with ThreadDetach.
An AV is sometimes raised (see MadExcept trace below) from within
the Execute procedure when csDestroying is in client's ComponentState.
I can work around that by checking for (Client.ComponentState = [])
but I don't think it's good practice. It happens only when the
destructor is called and a lot of threads are busy.
Any idea?
---
Arno Garrels [TeamICS]
Destructor of TThrdWSocketServer terminates the threads:
for I := 0 to FThreadList.Count -1 do
begin
AThread := TThread(FThreadList[I]);
if PostThreadMessage(AThread.ThreadID, WM_THREAD_TERMINATE, 0, 0) then
begin
Dec(FThreadCount);
Sleep(0);
end;
end;
WM_THREAD_TERMINATE exits PumpMessages()
procedure TWSClientThread.Execute;
var
I : Integer;
Client : TThrdWSocketClient;
Msg: TMsg;
begin
try
{ Initialize thread's message queue }
PeekMessage(Msg, 0, 0, 0, PM_NOREMOVE);
SetEvent(EventArray[THREAD_READY_EVENT]);
FReadyForMsgs := TRUE;
FClients := TList.Create;
try
PumpMessages(True);
if not Terminated then
Terminate;
InterlockedDecrement(FServer.FThreadCount);
for I := 0 to FClients.Count -1 do
begin
Client := FClients[I];
if Assigned(Client) then
Client.ThreadDetach; = *AV here
end;
finally
FClients.Free;
FClients := nil;
end;
finally
PostMessage(FServer.Handle, WM_THREAD_TERMINATED, Integer(Self), 0);
{ Just to make sure the main thread isn't waiting for this thread }
{ signal the events }
SetEvent(EventArray[CLIENT_REMOVED_EVENT]);
SetEvent(EventArray[CLIENT_ATTACHED_EVENT]);
end;
end;
exception class : EAccessViolation
exception message : Accessviolation at Address 0048C6C9 in Module 'TcpSrv.exe'.
Read from Address 0038.
thread $26c (TWsClientThread):
0048c6c9 TcpSrv.exe WSocket4159 TCustomWSocket.ThreadDetach
00495706 TcpSrv.exe WSocketS906 TWsClientThread.Execute
00442a36 TcpSrv.exe Classes9372 ThreadProc
004049dc TcpSrv.exe System11554 ThreadWrapper
0042bcbb TcpSrv.exe madExcept ThreadExceptFrame
created by main thread ($6ec) at:
0049539a TcpSrv.exe WSocketS787 TWsClientThread.Create
main thread ($6ec):
7c91eb94 ntdll.dll KiFastSystemCallRet
7c91e64c ntdll.dll NtSetInformationThread
thread $3fc: priority:1
7c91eb94 ntdll.dll KiFastSystemCallRet
7c91e319 ntdll.dll NtRemoveIoCompletion
thread $314:
stack not accessible
thread $798:
stack not accessible
thread $778:
stack not accessible
thread $90 (TWsClientThread):
7c91eb94 ntdll.dllKiFastSystemCallRet
7c91e9be ntdll.dllNtWaitForSingleObject
7c8025d5 kernel32.dll WaitForSingleObjectEx
7c80253d kernel32.dll WaitForSingleObject
00426e8a TcpSrv.exe madExcept HandleException
0042bd4d TcpSrv.exe madExcept HookedTThreadExecute
7c91eaf5 ntdll.dllKiUserExceptionDispatcher
0048c6c9 TcpSrv.exe WSocket4159 TCustomWSocket.ThreadDetach
00495706 TcpSrv.exe WSocketS906 TWsClientThread.Execute
00442a36 TcpSrv.exe Classes9372 ThreadProc
004049dc TcpSrv.exe System11554 ThreadWrapper
0042bcbb TcpSrv.exe madExcept ThreadExceptFrame
created by main thread ($6ec) at:
0049539a TcpSrv.exe WSocketS787 TWsClientThread.Create
thread $728:
stack not accessible
thread $374 (TWsClientThread):
7c91eb94 ntdll.dllKiFastSystemCallRet
7c91e9be ntdll.dllNtWaitForSingleObject
7c8025d5 kernel32.dll WaitForSingleObjectEx
7c80253d kernel32.dll WaitForSingleObject
00426e8a TcpSrv.exe madExcept HandleException
0042bd4d TcpSrv.exe madExcept HookedTThreadExecute
7c91eaf5 ntdll.dllKiUserExceptionDispatcher
0042bd26 TcpSrv.exe madExcept HookedTThreadExecute
00442a36 TcpSrv.exe Classes9372 ThreadProc
004049dc TcpSrv.exe System11554 ThreadWrapper
0042bcbb TcpSrv.exe madExcept ThreadExceptFrame
created by main thread ($6ec) at:
0049539a TcpSrv.exe WSocketS787 TWsClientThread.Create
disassembling:
0048c67c public WSocket.TCustomWSocket.ThreadDetach: ; function entry
point
0048c67c 4153 pushebp
0048c67dmov ebp, esp
0048c67fpushecx
0048c680mov [ebp-4], eax
0048c683 4154 call-$85750 ($406f38) ; Windows.GetCurrentThreadId
0048c683
0048c688mov edx, [ebp-4]
0048c68bcmp eax, [edx+$548]
0048c691jz loc_48c6a0
Re: [twsocket] Threaded TWSocketServer derivation
Isn't it possible that the client is already destroyed when you call
ThreadDetech ? If yes,
accessing self in ThreadDetach cause the access violation.
Each time a client is freed, it must be remove from the list to avoid this
problem.
--
Contribute to the SSL Effort. Visit
http://www.overbyte.be/eng/ssl.html
--
[EMAIL PROTECTED]
Author of ICS (Internet Component Suite, freeware)
Author of MidWare (Multi-tier framework, freeware)
http://www.overbyte.be
- Original Message -
From: Arno Garrels [EMAIL PROTECTED]
To: ICS support mailing twsocket@elists.org
Sent: Friday, November 04, 2005 12:14 PM
Subject: [twsocket] Threaded TWSocketServer derivation
Hello,
After a big fight with deadlocks and race conditions for one day my
threaded TWSocketServer derivation is now working stable.
(tested with Wilfrieds GPRS Client and other stressing clients)
But.. I have still a tiny problem with ThreadDetach.
An AV is sometimes raised (see MadExcept trace below) from within
the Execute procedure when csDestroying is in client's ComponentState.
I can work around that by checking for (Client.ComponentState = [])
but I don't think it's good practice. It happens only when the
destructor is called and a lot of threads are busy.
Any idea?
---
Arno Garrels [TeamICS]
Destructor of TThrdWSocketServer terminates the threads:
for I := 0 to FThreadList.Count -1 do
begin
AThread := TThread(FThreadList[I]);
if PostThreadMessage(AThread.ThreadID, WM_THREAD_TERMINATE, 0, 0) then
begin
Dec(FThreadCount);
Sleep(0);
end;
end;
WM_THREAD_TERMINATE exits PumpMessages()
procedure TWSClientThread.Execute;
var
I : Integer;
Client : TThrdWSocketClient;
Msg: TMsg;
begin
try
{ Initialize thread's message queue }
PeekMessage(Msg, 0, 0, 0, PM_NOREMOVE);
SetEvent(EventArray[THREAD_READY_EVENT]);
FReadyForMsgs := TRUE;
FClients := TList.Create;
try
PumpMessages(True);
if not Terminated then
Terminate;
InterlockedDecrement(FServer.FThreadCount);
for I := 0 to FClients.Count -1 do
begin
Client := FClients[I];
if Assigned(Client) then
Client.ThreadDetach; = *AV here
end;
finally
FClients.Free;
FClients := nil;
end;
finally
PostMessage(FServer.Handle, WM_THREAD_TERMINATED, Integer(Self), 0);
{ Just to make sure the main thread isn't waiting for this thread }
{ signal the events }
SetEvent(EventArray[CLIENT_REMOVED_EVENT]);
SetEvent(EventArray[CLIENT_ATTACHED_EVENT]);
end;
end;
exception class : EAccessViolation
exception message : Accessviolation at Address 0048C6C9 in Module
'TcpSrv.exe'. Read from Address
0038.
thread $26c (TWsClientThread):
0048c6c9 TcpSrv.exe WSocket4159 TCustomWSocket.ThreadDetach
00495706 TcpSrv.exe WSocketS906 TWsClientThread.Execute
00442a36 TcpSrv.exe Classes9372 ThreadProc
004049dc TcpSrv.exe System11554 ThreadWrapper
0042bcbb TcpSrv.exe madExcept ThreadExceptFrame
created by main thread ($6ec) at:
0049539a TcpSrv.exe WSocketS787 TWsClientThread.Create
main thread ($6ec):
7c91eb94 ntdll.dll KiFastSystemCallRet
7c91e64c ntdll.dll NtSetInformationThread
thread $3fc: priority:1
7c91eb94 ntdll.dll KiFastSystemCallRet
7c91e319 ntdll.dll NtRemoveIoCompletion
thread $314:
stack not accessible
thread $798:
stack not accessible
thread $778:
stack not accessible
thread $90 (TWsClientThread):
7c91eb94 ntdll.dllKiFastSystemCallRet
7c91e9be ntdll.dllNtWaitForSingleObject
7c8025d5 kernel32.dll WaitForSingleObjectEx
7c80253d kernel32.dll WaitForSingleObject
00426e8a TcpSrv.exe madExcept HandleException
0042bd4d TcpSrv.exe madExcept HookedTThreadExecute
7c91eaf5 ntdll.dllKiUserExceptionDispatcher
0048c6c9 TcpSrv.exe WSocket4159 TCustomWSocket.ThreadDetach
00495706 TcpSrv.exe WSocketS906 TWsClientThread.Execute
00442a36 TcpSrv.exe Classes9372 ThreadProc
004049dc TcpSrv.exe System11554 ThreadWrapper
0042bcbb TcpSrv.exe madExcept ThreadExceptFrame
created by main thread ($6ec) at:
0049539a TcpSrv.exe WSocketS787 TWsClientThread.Create
thread $728:
stack not accessible
thread $374 (TWsClientThread):
7c91eb94 ntdll.dllKiFastSystemCallRet
7c91e9be ntdll.dllNtWaitForSingleObject
7c8025d5 kernel32.dll WaitForSingleObjectEx
7c80253d kernel32.dll WaitForSingleObject
00426e8a TcpSrv.exe madExcept HandleException
0042bd4d TcpSrv.exe madExcept HookedTThreadExecute
7c91eaf5 ntdll.dll
Re: [twsocket] Threaded TWSocketServer derivation
Francois Piette wrote: Isn't it possible that the client is already destroyed when you call ThreadDetech ? If yes, accessing self in ThreadDetach cause the access violation. Yes, very simple, that seems to be the reason. I think I've fixed it by just waiting for all threads return and being freed manually in the main thread before going ahead in the destructor. Sometimes, when bugs are too obvious I don't find them :( --- Arno Garrels [TeamICS] -- To unsubscribe or change your settings for TWSocket mailing list please goto http://www.elists.org/mailman/listinfo/twsocket Visit our website at http://www.overbyte.be
Re: [twsocket] Fw: TCustomSmtpClient.AuthGetType
From: Vander Clock Stephane [..] I think you must replace S := Copy(S, 5, Length(S)); by S := Copy(S, 6, Length(S)); I don't know why, length of both strings is 5 not 6. Typically the lines in question of a EHLO response look like 250-AUTH=LOGIN CRAM-MD5 PLAIN 250-AUTH CRAM-MD5 LOGIN PLAIN --- Arno Garrels [TeamICS] -- To unsubscribe or change your settings for TWSocket mailing list please goto http://www.elists.org/mailman/listinfo/twsocket Visit our website at http://www.overbyte.be
Re: [twsocket] Fw: TCustomSmtpClient.AuthGetType
DZ-Jay wrote: since the CompareText calls Copy() with an Index of 1, which means that it starts to delete at the second character, not to mention the call to Delete() uses an Index of 1 also. This should have been: which means that it starts to copy at the second character... Sorry, dZ. -- To unsubscribe or change your settings for TWSocket mailing list please goto http://www.elists.org/mailman/listinfo/twsocket Visit our website at http://www.overbyte.be
