diff options
Diffstat (limited to 'win/tclWinPipe.c')
| -rw-r--r-- | win/tclWinPipe.c | 112 |
1 files changed, 75 insertions, 37 deletions
diff --git a/win/tclWinPipe.c b/win/tclWinPipe.c index 2134d8d..8a6fc59 100644 --- a/win/tclWinPipe.c +++ b/win/tclWinPipe.c @@ -9,7 +9,7 @@ * See the file "license.terms" for information on usage and redistribution * of this file, and for a DISCLAIMER OF ALL WARRANTIES. * - * RCS: @(#) $Id: tclWinPipe.c,v 1.26 2002/11/07 02:13:37 mdejong Exp $ + * RCS: @(#) $Id: tclWinPipe.c,v 1.27 2002/11/26 22:35:20 davygrvy Exp $ */ #include "tclWinInt.h" @@ -120,6 +120,8 @@ typedef struct PipeInfo { HANDLE startWriter; /* Auto-reset event used by the main thread to * signal when the writer thread should attempt * to write to the pipe. */ + HANDLE stopWriter; /* Manual-reset event used to alert the reader + * thread to fall-out and exit */ HANDLE startReader; /* Auto-reset event used by the main thread to * signal when the reader thread should attempt * to read from the pipe. */ @@ -1685,7 +1687,7 @@ TclpCreateCommandChannel( infoPtr->readable = CreateEvent(NULL, TRUE, TRUE, NULL); infoPtr->startReader = CreateEvent(NULL, FALSE, FALSE, NULL); infoPtr->stopReader = CreateEvent(NULL, TRUE, FALSE, NULL); - infoPtr->readThread = CreateThread(NULL, 512, PipeReaderThread, + infoPtr->readThread = CreateThread(NULL, 256, PipeReaderThread, infoPtr, 0, &id); SetThreadPriority(infoPtr->readThread, THREAD_PRIORITY_HIGHEST); infoPtr->validMask |= TCL_READABLE; @@ -1699,7 +1701,8 @@ TclpCreateCommandChannel( infoPtr->writable = CreateEvent(NULL, TRUE, TRUE, NULL); infoPtr->startWriter = CreateEvent(NULL, FALSE, FALSE, NULL); - infoPtr->writeThread = CreateThread(NULL, 512, PipeWriterThread, + infoPtr->stopWriter = CreateEvent(NULL, TRUE, FALSE, NULL); + infoPtr->writeThread = CreateThread(NULL, 256, PipeWriterThread, infoPtr, 0, &id); SetThreadPriority(infoPtr->readThread, THREAD_PRIORITY_HIGHEST); infoPtr->validMask |= TCL_WRITABLE; @@ -1873,13 +1876,11 @@ PipeClose2Proc( SetEvent(pipePtr->stopReader); /* - * Wait at most 10 milliseconds for the reader thread to close. + * Wait at most 20 milliseconds for the reader thread to close. */ - WaitForSingleObject(pipePtr->readThread, 10); - GetExitCodeThread(pipePtr->readThread, &exitCode); - - if (exitCode == STILL_ACTIVE) { + if (WaitForSingleObject(pipePtr->readThread, 20) + == WAIT_TIMEOUT) { /* * The thread must be blocked waiting for the pipe to * become readable in ReadFile(). There isn't a clean way @@ -1898,10 +1899,6 @@ PipeClose2Proc( /* BUG: this leaks memory */ TerminateThread(pipePtr->readThread, 0); - - /* Wait for the thread to terminate. */ - WaitForSingleObject(pipePtr->readThread, INFINITE); - Tcl_MutexUnlock(&pipeMutex); } } @@ -1920,40 +1917,65 @@ PipeClose2Proc( } if ((!flags || (flags & TCL_CLOSE_WRITE)) && (pipePtr->writeFile != NULL)) { - /* - * Wait for the writer thread to finish the current buffer, then - * terminate the thread and close the handles. If the channel is - * nonblocking, there should be no pending write operations. - */ if (pipePtr->writeThread) { - WaitForSingleObject(pipePtr->writable, INFINITE); - /* - * Forcibly terminate the background thread. We cannot rely on the - * thread to cleanly terminate itself because we have no way of - * closing the pipe handle without blocking in the case where the - * thread is in the middle of an I/O operation. Note that we need - * to guard against terminating the thread while it is in the - * middle of Tcl_ThreadAlert because it won't be able to release - * the notifier lock. + * Wait for the writer thread to finish the current buffer, + * then terminate the thread and close the handles. If the + * channel is nonblocking, there should be no pending write + * operations. */ - Tcl_MutexLock(&pipeMutex); - TerminateThread(pipePtr->writeThread, 0); + WaitForSingleObject(pipePtr->writable, INFINITE); /* - * Wait for the thread to terminate. This ensures that we are - * completely cleaned up before we leave this function. + * The thread may already have closed on it's own. Check it's + * exit code. */ - WaitForSingleObject(pipePtr->writeThread, INFINITE); - Tcl_MutexUnlock(&pipeMutex); + GetExitCodeThread(pipePtr->writeThread, &exitCode); + + if (exitCode == STILL_ACTIVE) { + /* + * Set the stop event so that if the reader thread is blocked + * in PipeReaderThread on WaitForMultipleEvents, it will exit + * cleanly. + */ + + SetEvent(pipePtr->stopWriter); + + /* + * Wait at most 20 milliseconds for the reader thread to close. + */ + + if (WaitForSingleObject(pipePtr->writeThread, 20) + == WAIT_TIMEOUT) { + /* + * The thread must be blocked waiting for the pipe to + * consume input in WriteFile(). There isn't a clean way + * to exit the thread from this condition. We should + * terminate the child process instead to get the writer + * thread to fall out of WriteFile with a FALSE. (below) is + * not the correct way to do this, but will stay here until + * a better solution is found. + * + * Note that we need to guard against terminating the + * thread while it is in the middle of Tcl_ThreadAlert + * because it won't be able to release the notifier lock. + */ + Tcl_MutexLock(&pipeMutex); + + /* BUG: this leaks memory */ + TerminateThread(pipePtr->writeThread, 0); + Tcl_MutexUnlock(&pipeMutex); + } + } CloseHandle(pipePtr->writeThread); CloseHandle(pipePtr->writable); CloseHandle(pipePtr->startWriter); + CloseHandle(pipePtr->stopWriter); pipePtr->writeThread = NULL; } if (TclpCloseFile(pipePtr->writeFile) != 0) { @@ -2745,7 +2767,7 @@ PipeReaderThread(LPVOID arg) DWORD count, err; int done = 0; HANDLE wEvents[2]; - DWORD dwWait; + DWORD waitResult; wEvents[0] = infoPtr->stopReader; wEvents[1] = infoPtr->startReader; @@ -2756,15 +2778,15 @@ PipeReaderThread(LPVOID arg) * on the pipe becoming readable. */ - dwWait = WaitForMultipleObjects(2, wEvents, FALSE, INFINITE); + waitResult = WaitForMultipleObjects(2, wEvents, FALSE, INFINITE); - if (dwWait != (WAIT_OBJECT_0 + 1)) { + if (waitResult != (WAIT_OBJECT_0 + 1)) { /* * The start event was not signaled. It might be the stop event * or an error, so exit. */ - return 0; + break; } /* @@ -2832,6 +2854,7 @@ PipeReaderThread(LPVOID arg) Tcl_ThreadAlert(infoPtr->threadId); Tcl_MutexUnlock(&pipeMutex); } + return 0; } @@ -2862,13 +2885,27 @@ PipeWriterThread(LPVOID arg) DWORD count, toWrite; char *buf; int done = 0; + HANDLE wEvents[2]; + DWORD waitResult; + + wEvents[0] = infoPtr->stopWriter; + wEvents[1] = infoPtr->startWriter; while (!done) { /* * Wait for the main thread to signal before attempting to write. */ - WaitForSingleObject(infoPtr->startWriter, INFINITE); + waitResult = WaitForMultipleObjects(2, wEvents, FALSE, INFINITE); + + if (waitResult != (WAIT_OBJECT_0 + 1)) { + /* + * The start event was not signaled. It might be the stop event + * or an error, so exit. + */ + + break; + } buf = infoPtr->writeBuf; toWrite = infoPtr->toWrite; @@ -2905,6 +2942,7 @@ PipeWriterThread(LPVOID arg) Tcl_ThreadAlert(infoPtr->threadId); Tcl_MutexUnlock(&pipeMutex); } + return 0; } |