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authorsebres <sebres@users.sourceforge.net>2017-04-11 18:09:52 (GMT)
committersebres <sebres@users.sourceforge.net>2017-04-11 18:09:52 (GMT)
commit992af585dd13c64af68e50f9cad503afb6f0b1ed (patch)
treeee00c2a8984fdb59a627dcf91aa833b2bc168fe3 /win/tclWinConsole.c
parent3ae2132f422286c745ba221dc1076475957fc2f8 (diff)
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code review, robustness increase, avoid infinite wait by exit, thread exit and by pipes of closed processes);
use pipe-helpers (TI-structure handling) for all pipe-workers (tclWinConsole, tclWinSerial);
Diffstat (limited to 'win/tclWinConsole.c')
-rw-r--r--win/tclWinConsole.c281
1 files changed, 75 insertions, 206 deletions
diff --git a/win/tclWinConsole.c b/win/tclWinConsole.c
index da995c5..7a0965d 100644
--- a/win/tclWinConsole.c
+++ b/win/tclWinConsole.c
@@ -51,16 +51,10 @@ TCL_DECLARE_MUTEX(consoleMutex)
typedef struct ConsoleThreadInfo {
HANDLE thread; /* Handle to reader or writer thread. */
- int threadExiting; /* Boolean indicating that thread is exiting. */
HANDLE readyEvent; /* Manual-reset event to signal _to_ the main
* thread when the worker thread has finished
* waiting for its normal work to happen. */
- HANDLE startEvent; /* Auto-reset event used by the main thread to
- * signal when the thread should attempt to do
- * its normal work. Additionally this event
- * used as wait for thread event (init phase). */
- HANDLE stopEvent; /* Auto-reset event used by the main thread to
- * signal when the thread should exit. */
+ TclPipeThreadInfo *TI; /* Thread info structure of writer and reader. */
} ConsoleThreadInfo;
/*
@@ -84,16 +78,14 @@ typedef struct ConsoleInfo {
* threads. */
ConsoleThreadInfo writer; /* A specialized thread for handling
* asynchronous writes to the console; the
- * waiting starts when a start event is sent,
+ * waiting starts when a control event is sent,
* and a reset event is sent back to the main
- * thread when the write is done. A stop event
- * is used to terminate the thread. */
+ * thread when the write is done. */
ConsoleThreadInfo reader; /* A specialized thread for handling
* asynchronous reads from the console; the
- * waiting starts when a start event is sent,
+ * waiting starts when a control event is sent,
* and a reset event is sent back to the main
- * thread when input is available. A stop
- * event is used to terminate the thread. */
+ * thread when input is available. */
DWORD writeError; /* An error caused by the last background
* write. Set to 0 if no error has been
* detected. This word is shared with the
@@ -170,10 +162,6 @@ static BOOL ReadConsoleBytes(HANDLE hConsole, LPVOID lpBuffer,
static BOOL WriteConsoleBytes(HANDLE hConsole,
const void *lpBuffer, DWORD nbytes,
LPDWORD nbyteswritten);
-static void StartChannelThread(ConsoleInfo *infoPtr,
- ConsoleThreadInfo *threadInfoPtr,
- LPTHREAD_START_ROUTINE threadProc);
-static void StopChannelThread(ConsoleThreadInfo *threadInfoPtr);
/*
* This structure describes the channel type structure for command console
@@ -520,102 +508,6 @@ ConsoleBlockModeProc(
/*
*----------------------------------------------------------------------
*
- * StartChannelThread, StopChannelThread --
- *
- * Helpers that codify how to ask one of the console service threads to
- * start and stop.
- *
- *----------------------------------------------------------------------
- */
-
-static void
-StartChannelThread(
- ConsoleInfo *infoPtr,
- ConsoleThreadInfo *threadInfoPtr,
- LPTHREAD_START_ROUTINE threadProc)
-{
- DWORD id;
-
- threadInfoPtr->readyEvent = CreateEvent(NULL, TRUE, TRUE, NULL);
- threadInfoPtr->startEvent = CreateEvent(NULL, FALSE, FALSE, NULL);
- threadInfoPtr->threadExiting = FALSE;
- threadInfoPtr->stopEvent = CreateEvent(NULL, FALSE, FALSE, NULL);
- threadInfoPtr->thread = CreateThread(NULL, 256, threadProc, infoPtr, 0,
- &id);
- SetThreadPriority(threadInfoPtr->thread, THREAD_PRIORITY_HIGHEST);
-}
-
-static void
-StopChannelThread(
- ConsoleThreadInfo *threadInfoPtr)
-{
- DWORD exitCode = 0;
-
- /*
- * The thread may already have closed on it's own. Check it's exit
- * code.
- */
-
- GetExitCodeThread(threadInfoPtr->thread, &exitCode);
- if (exitCode == STILL_ACTIVE) {
- /*
- * Set the stop event so that if the reader thread is blocked in
- * ConsoleReaderThread on WaitForMultipleEvents, it will exit cleanly.
- */
-
- SetEvent(threadInfoPtr->stopEvent);
-
- /*
- * Wait at most 20 milliseconds for the reader thread to close.
- */
-
- if (WaitForSingleObject(threadInfoPtr->thread, 20) == WAIT_TIMEOUT) {
- /*
- * Forcibly terminate the background thread as a last resort.
- * 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.
- *
- * Also note that terminating threads during their initialization or teardown phase
- * may result in ntdll.dll's LoaderLock to remain locked indefinitely.
- * This causes ntdll.dll's LdrpInitializeThread() to deadlock trying to acquire LoaderLock.
- * LdrpInitializeThread() is executed within new threads to perform
- * initialization and to execute DllMain() of all loaded dlls.
- * As a result, all new threads are deadlocked in their initialization phase and never execute,
- * even though CreateThread() reports successful thread creation.
- * This results in a very weird process-wide behavior, which is extremely hard to debug.
- *
- * THREADS SHOULD NEVER BE TERMINATED. Period.
- *
- * But for now, check if thread is exiting, and if so, let it die peacefully.
- */
-
- if ( !threadInfoPtr->threadExiting
- || WaitForSingleObject(threadInfoPtr->thread, 5000) != WAIT_OBJECT_0
- ) {
- Tcl_MutexLock(&consoleMutex);
- /* BUG: this leaks memory. */
- TerminateThread(threadInfoPtr->thread, 0);
- Tcl_MutexUnlock(&consoleMutex);
- }
- }
- }
-
- /*
- * Close all the handles associated with the thread, and set the thread
- * handle field to NULL to mark that the thread has been cleaned up.
- */
-
- CloseHandle(threadInfoPtr->thread);
- CloseHandle(threadInfoPtr->readyEvent);
- CloseHandle(threadInfoPtr->startEvent);
- CloseHandle(threadInfoPtr->stopEvent);
- threadInfoPtr->thread = NULL;
-}
-
-/*
- *----------------------------------------------------------------------
- *
* ConsoleCloseProc --
*
* Closes a console based IO channel.
@@ -646,7 +538,10 @@ ConsoleCloseProc(
*/
if (consolePtr->reader.thread) {
- StopChannelThread(&consolePtr->reader);
+ TclPipeThreadStop(&consolePtr->reader.TI, consolePtr->reader.thread);
+ CloseHandle(consolePtr->reader.thread);
+ CloseHandle(consolePtr->reader.readyEvent);
+ consolePtr->reader.thread = NULL;
}
consolePtr->validMask &= ~TCL_READABLE;
@@ -663,10 +558,13 @@ ConsoleCloseProc(
* prevent infinite wait on exit. [Python Bug 216289]
*/
- WaitForSingleObject(consolePtr->writer.readyEvent, INFINITE);
+ WaitForSingleObject(consolePtr->writer.readyEvent, 5000);
}
- StopChannelThread(&consolePtr->writer);
+ TclPipeThreadStop(&consolePtr->writer.TI, consolePtr->writer.thread);
+ CloseHandle(consolePtr->writer.thread);
+ CloseHandle(consolePtr->writer.readyEvent);
+ consolePtr->writer.thread = NULL;
}
consolePtr->validMask &= ~TCL_WRITABLE;
@@ -832,8 +730,11 @@ ConsoleOutputProc(
DWORD bytesWritten, timeout;
*errorCode = 0;
- timeout = (infoPtr->flags & CONSOLE_ASYNC) ? 0 : INFINITE;
- if (WaitForSingleObject(threadInfo->readyEvent,timeout) == WAIT_TIMEOUT) {
+
+ /* avoid blocking if pipe-thread exited */
+ timeout = (infoPtr->flags & CONSOLE_ASYNC) || !TclPipeThreadIsAlive(&threadInfo->TI)
+ || TclInExit() || TclInThreadExit() ? 0 : INFINITE;
+ if (WaitForSingleObject(threadInfo->readyEvent, timeout) == WAIT_TIMEOUT) {
/*
* The writer thread is blocked waiting for a write to complete and
* the channel is in non-blocking mode.
@@ -873,7 +774,7 @@ ConsoleOutputProc(
memcpy(infoPtr->writeBuf, buf, (size_t) toWrite);
infoPtr->toWrite = toWrite;
ResetEvent(threadInfo->readyEvent);
- SetEvent(threadInfo->startEvent);
+ TclPipeThreadSignal(&threadInfo->TI);
bytesWritten = toWrite;
} else {
/*
@@ -1110,9 +1011,10 @@ WaitForRead(
* Synchronize with the reader thread.
*/
- timeout = blocking ? INFINITE : 0;
- if (WaitForSingleObject(threadInfo->readyEvent,
- timeout) == WAIT_TIMEOUT) {
+ /* avoid blocking if pipe-thread exited */
+ timeout = (!blocking || !TclPipeThreadIsAlive(&threadInfo->TI)
+ || TclInExit() || TclInThreadExit()) ? 0 : INFINITE;
+ if (WaitForSingleObject(threadInfo->readyEvent, timeout) == WAIT_TIMEOUT) {
/*
* The reader thread is blocked waiting for data and the channel
* is in non-blocking mode.
@@ -1172,7 +1074,7 @@ WaitForRead(
*/
ResetEvent(threadInfo->readyEvent);
- SetEvent(threadInfo->startEvent);
+ TclPipeThreadSignal(&threadInfo->TI);
}
}
@@ -1199,39 +1101,27 @@ static DWORD WINAPI
ConsoleReaderThread(
LPVOID arg)
{
- ConsoleInfo *infoPtr = arg;
- HANDLE *handle = infoPtr->handle;
- ConsoleThreadInfo *threadInfo = &infoPtr->reader;
- DWORD waitResult;
- HANDLE wEvents[2];
-
- /*
- * Notify caller (using startEvent) that this thread is initialized
- */
- SignalObjectAndWait(threadInfo->startEvent, threadInfo->stopEvent, INFINITE, FALSE);
-
- /*
- * The first event takes precedence.
- */
-
- wEvents[0] = threadInfo->stopEvent;
- wEvents[1] = threadInfo->startEvent;
-
- for (;;) {
+ TclPipeThreadInfo *pipeTI = (TclPipeThreadInfo *)arg;
+ ConsoleInfo *infoPtr = NULL; /* access info only after success init/wait */
+ HANDLE *handle = NULL;
+ ConsoleThreadInfo *threadInfo = NULL;
+ int done = 0;
+
+ while (!done) {
/*
- * Wait for the main thread to signal before attempting to wait.
+ * Wait for the main thread to signal before attempting to read.
*/
- waitResult = WaitForMultipleObjects(2, wEvents, FALSE, INFINITE);
-
- if (waitResult != (WAIT_OBJECT_0 + 1)) {
- /*
- * The start event was not signaled. It must be the stop event or
- * an error, so exit this thread.
- */
-
+ if (!TclPipeThreadWaitForSignal(&pipeTI)) {
+ /* exit */
break;
}
+ if (!infoPtr) {
+ infoPtr = (ConsoleInfo *)pipeTI->clientData;
+ handle = infoPtr->handle;
+ threadInfo = &infoPtr->reader;
+ }
+
/*
* Look for data on the console, but first ignore any events that are
@@ -1251,6 +1141,7 @@ ConsoleReaderThread(
if (err == (DWORD) EOF) {
infoPtr->readFlags = CONSOLE_EOF;
}
+ done = 1;
}
/*
@@ -1278,11 +1169,8 @@ ConsoleReaderThread(
Tcl_MutexUnlock(&consoleMutex);
}
- /*
- * Inform caller that this thread should not be terminated, since it is about to exit.
- * See comment in StopChannelThread() for reasons.
- */
- threadInfo->threadExiting = TRUE;
+ /* Worker exit, so inform the main thread or free TI-structure (if owned) */
+ TclPipeThreadExit(&pipeTI);
return 0;
}
@@ -1310,40 +1198,27 @@ static DWORD WINAPI
ConsoleWriterThread(
LPVOID arg)
{
- ConsoleInfo *infoPtr = arg;
- HANDLE *handle = infoPtr->handle;
- ConsoleThreadInfo *threadInfo = &infoPtr->writer;
- DWORD count, toWrite, waitResult;
+ TclPipeThreadInfo *pipeTI = (TclPipeThreadInfo *)arg;
+ ConsoleInfo *infoPtr = NULL; /* access info only after success init/wait */
+ HANDLE *handle = NULL;
+ ConsoleThreadInfo *threadInfo = NULL;
+ DWORD count, toWrite;
char *buf;
- HANDLE wEvents[2];
-
- /*
- * Notify caller (using startEvent) that this thread is initialized
- */
- SignalObjectAndWait(threadInfo->startEvent, threadInfo->stopEvent, INFINITE, FALSE);
-
- /*
- * The first event takes precedence.
- */
-
- wEvents[0] = threadInfo->stopEvent;
- wEvents[1] = threadInfo->startEvent;
-
- for (;;) {
+ int done = 0;
+
+ while (!done) {
/*
* Wait for the main thread to signal before attempting to write.
*/
-
- waitResult = WaitForMultipleObjects(2, wEvents, FALSE, INFINITE);
-
- if (waitResult != (WAIT_OBJECT_0 + 1)) {
- /*
- * The start event was not signaled. It must be the stop event or
- * an error, so exit this thread.
- */
-
+ if (!TclPipeThreadWaitForSignal(&pipeTI)) {
+ /* exit */
break;
}
+ if (!infoPtr) {
+ infoPtr = (ConsoleInfo *)pipeTI->clientData;
+ handle = infoPtr->handle;
+ threadInfo = &infoPtr->writer;
+ }
buf = infoPtr->writeBuf;
toWrite = infoPtr->toWrite;
@@ -1356,6 +1231,7 @@ ConsoleWriterThread(
if (WriteConsoleBytes(handle, buf, (DWORD) toWrite,
&count) == FALSE) {
infoPtr->writeError = GetLastError();
+ done = 1;
break;
}
toWrite -= count;
@@ -1387,11 +1263,8 @@ ConsoleWriterThread(
Tcl_MutexUnlock(&consoleMutex);
}
- /*
- * Inform caller that this thread should not be terminated, since it is about to exit.
- * See comment in StopChannelThread() for reasons.
- */
- threadInfo->threadExiting = TRUE;
+ /* Worker exit, so inform the main thread or free TI-structure (if owned) */
+ TclPipeThreadExit(&pipeTI);
return 0;
}
@@ -1422,8 +1295,7 @@ TclWinOpenConsoleChannel(
{
char encoding[4 + TCL_INTEGER_SPACE];
ConsoleInfo *infoPtr;
- DWORD modes, wEventsCnt = 0;
- HANDLE wEvents[2], wEventsPtr = wEvents;
+ DWORD modes;
ConsoleInit();
@@ -1464,26 +1336,23 @@ TclWinOpenConsoleChannel(
modes &= ~(ENABLE_WINDOW_INPUT | ENABLE_MOUSE_INPUT);
modes |= ENABLE_LINE_INPUT;
SetConsoleMode(infoPtr->handle, modes);
- StartChannelThread(infoPtr, &infoPtr->reader, ConsoleReaderThread);
- wEvents[wEventsCnt++] = infoPtr->reader.startEvent;
+
+ infoPtr->reader.readyEvent = CreateEvent(NULL, TRUE, TRUE, NULL);
+ infoPtr->reader.thread = CreateThread(NULL, 256, ConsoleReaderThread,
+ TclPipeThreadCreateTI(&infoPtr->reader.TI, infoPtr,
+ infoPtr->reader.readyEvent), 0, NULL);
+ SetThreadPriority(infoPtr->reader.thread, THREAD_PRIORITY_HIGHEST);
}
if (permissions & TCL_WRITABLE) {
- StartChannelThread(infoPtr, &infoPtr->writer, ConsoleWriterThread);
- wEvents[wEventsCnt++] = infoPtr->writer.startEvent;
- }
- /*
- * Wait for both threads to initialize (using theirs startEvent)
- */
- if (wEventsCnt) {
- WaitForMultipleObjects(wEventsCnt, wEvents, TRUE, 5000);
- /* Resume both waiting threads, we've get the events */
- if (infoPtr->reader.thread)
- SetEvent(infoPtr->reader.stopEvent);
- if (infoPtr->writer.thread)
- SetEvent(infoPtr->writer.stopEvent);
+ infoPtr->writer.readyEvent = CreateEvent(NULL, TRUE, TRUE, NULL);
+ infoPtr->writer.thread = CreateThread(NULL, 256, ConsoleWriterThread,
+ TclPipeThreadCreateTI(&infoPtr->writer.TI, infoPtr,
+ infoPtr->writer.readyEvent), 0, NULL);
+ SetThreadPriority(infoPtr->writer.thread, THREAD_PRIORITY_HIGHEST);
}
+
/*
* Files have default translation of AUTO and ^Z eof char, which means
* that a ^Z will be accepted as EOF when reading.