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authorandreask <andreask>2012-05-09 19:09:51 (GMT)
committerandreask <andreask>2012-05-09 19:09:51 (GMT)
commit77fc0e1330207148cd7a2e3c27a788ad2fed3cb0 (patch)
tree37e4e46bdd84967a8687cefad0aacc23728bf2e9 /generic
parent8a18bdefa3ff38b52d35a5cb1420dfe24b2e4c6a (diff)
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* generic/tclIORChan.c [Bug 3522560]: Fixed the crash, enabled the
test case. Modified [chan postevent] to properly inject the event(s) into the owner thread's event queue for execution in the correct context. Renamed the ForwardOpTo...Thread() function to match with our terminology.
Diffstat (limited to 'generic')
-rw-r--r--generic/tclIO.c2
-rw-r--r--generic/tclIORChan.c174
2 files changed, 160 insertions, 16 deletions
diff --git a/generic/tclIO.c b/generic/tclIO.c
index 86ee6ed..9e729c4 100644
--- a/generic/tclIO.c
+++ b/generic/tclIO.c
@@ -8760,7 +8760,7 @@ CreateScriptRecord(
/*
* Initialize the structure before calling Tcl_CreateChannelHandler,
- * because a reflected channel caling 'chan postevent' aka
+ * because a reflected channel calling 'chan postevent' aka
* 'Tcl_NotifyChannel' in its 'watch'Proc will invoke
* 'TclChannelEventScriptInvoker' immediately, and we do not wish it to
* see uninitialized memory and crash. See [Bug 2918110].
diff --git a/generic/tclIORChan.c b/generic/tclIORChan.c
index 49e2930..76002f6 100644
--- a/generic/tclIORChan.c
+++ b/generic/tclIORChan.c
@@ -39,6 +39,9 @@ static int ReflectOutput(ClientData clientData, const char *buf,
int toWrite, int *errorCodePtr);
static void ReflectWatch(ClientData clientData, int mask);
static int ReflectBlock(ClientData clientData, int mode);
+#ifdef TCL_THREADS
+static void ReflectThread(ClientData clientData, int action);
+#endif
static Tcl_WideInt ReflectSeekWide(ClientData clientData,
Tcl_WideInt offset, int mode, int *errorCodePtr);
static int ReflectSeek(ClientData clientData, long offset,
@@ -71,7 +74,11 @@ static const Tcl_ChannelType tclRChannelType = {
NULL, /* Flush channel. Not used by core. NULL'able */
NULL, /* Handle events. NULL'able */
ReflectSeekWide, /* Move access point (64 bit). NULL'able */
+#ifdef TCL_THREADS
+ ReflectThread, /* thread action, tracking owner */
+#else
NULL, /* thread action */
+#endif
NULL /* truncate */
};
@@ -89,7 +96,8 @@ typedef struct {
* command is gone.
*/
#ifdef TCL_THREADS
- Tcl_ThreadId thread; /* Thread the 'interp' belongs to. */
+ Tcl_ThreadId thread; /* Thread the 'interp' belongs to. == Handler thread */
+ Tcl_ThreadId owner; /* Thread owning the structure. == Channel thread */
#endif
/* See [==] as well.
@@ -390,7 +398,7 @@ TCL_DECLARE_MUTEX(rcForwardMutex)
* leak resources when threads go away.
*/
-static void ForwardOpToOwnerThread(ReflectedChannel *rcPtr,
+static void ForwardOpToHandlerThread(ReflectedChannel *rcPtr,
ForwardedOperation op, const void *param);
static int ForwardProc(Tcl_Event *evPtr, int mask);
static void SrcExitProc(ClientData clientData);
@@ -765,6 +773,48 @@ TclChanCreateObjCmd(
*----------------------------------------------------------------------
*/
+typedef struct ReflectEvent {
+ Tcl_Event header;
+ ReflectedChannel* rcPtr;
+ int events;
+} ReflectEvent;
+
+static int
+ReflectEventRun (Tcl_Event* ev, int flags)
+{
+ /* OWNER thread
+ *
+ * Note: When the channel is closed any pending events of this type are
+ * deleted. See ReflectClose() for the Tcl_DeleteEvents() calls
+ * accomplishing that.
+ */
+
+ ReflectEvent* e = (ReflectEvent*) ev;
+
+ Tcl_NotifyChannel (e->rcPtr->chan, e->events);
+ return 1;
+}
+
+static int
+ReflectEventDelete (Tcl_Event* ev, ClientData cd)
+{
+ /* OWNER thread
+ *
+ * Invoked by DeleteThreadReflectedChannelMap() and ReflectClose(). The
+ * latter ensures that no pending events of this type are run on an
+ * invalid channel.
+ */
+
+ ReflectEvent* e = (ReflectEvent*) ev;
+
+ if ((ev->proc != ReflectEventRun) ||
+ ((cd != NULL) &&
+ (cd != e->rcPtr))) {
+ return 0;
+ }
+ return 1;
+}
+
int
TclChanPostEventObjCmd(
ClientData clientData,
@@ -773,6 +823,8 @@ TclChanPostEventObjCmd(
Tcl_Obj *const *objv)
{
/*
+ * Ensure -> HANDLER thread
+ *
* Syntax: chan postevent CHANNEL EVENTSPEC
* [0] [1] [2] [3]
*
@@ -882,7 +934,38 @@ TclChanPostEventObjCmd(
* We have the channel and the events to post.
*/
- Tcl_NotifyChannel(chan, events);
+ {
+ ReflectEvent* ev = ckalloc (sizeof (ReflectEvent));
+ ev->header.proc = ReflectEventRun;
+ ev->events = events;
+ ev->rcPtr = rcPtr;
+
+ /*
+ * We are not preserving the structure here. When the channel is
+ * closed any pending events are deleted, see ReflectClose(), and
+ * ReflectEventDelete(). Trying to preserve and later release when the
+ * event is run may generate a situation where the channel structure
+ * is deleted but not our structure, crashing in
+ * FreeReflectedChannel().
+ */
+
+ /* Force creation of the RCM, for proper cleanup on thread teardown */
+ /* The teardown of unprocessed events is currently coupled to the thread reflected channel map */
+ (void) GetThreadReflectedChannelMap ();
+
+ if (rcPtr->owner == rcPtr->thread) {
+ Tcl_QueueEvent ((Tcl_Event*) ev, TCL_QUEUE_TAIL);
+ } else {
+ /* XXX Race condition !!
+ * XXX The destination thread may not exist anymore already.
+ * XXX (Delayed postevent executed after channel got removed).
+ * XXX Can we detect this ? (check the validity of the owner threadid ?)
+ * XXX Actually, in that case the channel should be dead also !
+ */
+ Tcl_ThreadQueueEvent (rcPtr->owner, (Tcl_Event*) ev, TCL_QUEUE_TAIL);
+ Tcl_ThreadAlert (rcPtr->owner);
+ }
+ }
/*
* Squash interp results left by the event script.
@@ -1067,9 +1150,12 @@ ReflectClose(
if (rcPtr->thread != Tcl_GetCurrentThread()) {
ForwardParam p;
- ForwardOpToOwnerThread(rcPtr, ForwardedClose, &p);
+ ForwardOpToHandlerThread(rcPtr, ForwardedClose, &p);
result = p.base.code;
+ /* Now squash the pending reflection events for this channel. */
+ Tcl_DeleteEvents (ReflectEventDelete, rcPtr);
+
if (result != TCL_OK) {
FreeReceivedError(&p);
}
@@ -1100,9 +1186,12 @@ ReflectClose(
if (rcPtr->thread != Tcl_GetCurrentThread()) {
ForwardParam p;
- ForwardOpToOwnerThread(rcPtr, ForwardedClose, &p);
+ ForwardOpToHandlerThread(rcPtr, ForwardedClose, &p);
result = p.base.code;
+ /* Now squash the pending reflection events for this channel. */
+ Tcl_DeleteEvents (ReflectEventDelete, rcPtr);
+
Tcl_EventuallyFree (rcPtr, (Tcl_FreeProc *) FreeReflectedChannel);
if (result != TCL_OK) {
@@ -1207,7 +1296,7 @@ ReflectInput(
p.input.buf = buf;
p.input.toRead = toRead;
- ForwardOpToOwnerThread(rcPtr, ForwardedInput, &p);
+ ForwardOpToHandlerThread(rcPtr, ForwardedInput, &p);
if (p.base.code != TCL_OK) {
if (p.base.code < 0) {
@@ -1322,7 +1411,7 @@ ReflectOutput(
p.output.buf = buf;
p.output.toWrite = toWrite;
- ForwardOpToOwnerThread(rcPtr, ForwardedOutput, &p);
+ ForwardOpToHandlerThread(rcPtr, ForwardedOutput, &p);
if (p.base.code != TCL_OK) {
if (p.base.code < 0) {
@@ -1438,7 +1527,7 @@ ReflectSeekWide(
p.seek.seekMode = seekMode;
p.seek.offset = offset;
- ForwardOpToOwnerThread(rcPtr, ForwardedSeek, &p);
+ ForwardOpToHandlerThread(rcPtr, ForwardedSeek, &p);
if (p.base.code != TCL_OK) {
PassReceivedError(rcPtr->chan, &p);
@@ -1562,7 +1651,7 @@ ReflectWatch(
ForwardParam p;
p.watch.mask = mask;
- ForwardOpToOwnerThread(rcPtr, ForwardedWatch, &p);
+ ForwardOpToHandlerThread(rcPtr, ForwardedWatch, &p);
/*
* Any failure from the forward is ignored. We have no place to put
@@ -1620,7 +1709,7 @@ ReflectBlock(
p.block.nonblocking = nonblocking;
- ForwardOpToOwnerThread(rcPtr, ForwardedBlock, &p);
+ ForwardOpToHandlerThread(rcPtr, ForwardedBlock, &p);
if (p.base.code != TCL_OK) {
PassReceivedError(rcPtr->chan, &p);
@@ -1650,6 +1739,42 @@ ReflectBlock(
return errorNum;
}
+#ifdef TCL_THREADS
+/*
+ *----------------------------------------------------------------------
+ *
+ * ReflectThread --
+ *
+ * This function is invoked to tell the channel about thread movements.
+ *
+ * Results:
+ * None.
+ *
+ * Side effects:
+ * Allocates memory. Arbitrary, as it calls upon a script.
+ *
+ *----------------------------------------------------------------------
+ */
+
+static void
+ReflectThread(ClientData clientData, int action)
+{
+ ReflectedChannel *rcPtr = clientData;
+
+ switch (action) {
+ case TCL_CHANNEL_THREAD_INSERT:
+ rcPtr->owner = Tcl_GetCurrentThread();
+ break;
+ case TCL_CHANNEL_THREAD_REMOVE:
+ rcPtr->owner = NULL;
+ break;
+ default:
+ Tcl_Panic ("Unknown thread action code.");
+ break;
+ }
+}
+
+#endif
/*
*----------------------------------------------------------------------
*
@@ -1689,7 +1814,7 @@ ReflectSetOption(
p.setOpt.name = optionName;
p.setOpt.value = newValue;
- ForwardOpToOwnerThread(rcPtr, ForwardedSetOpt, &p);
+ ForwardOpToHandlerThread(rcPtr, ForwardedSetOpt, &p);
if (p.base.code != TCL_OK) {
Tcl_Obj *err = Tcl_NewStringObj(p.base.msgStr, -1);
@@ -1775,7 +1900,7 @@ ReflectGetOption(
opcode = ForwardedGetOpt;
}
- ForwardOpToOwnerThread(rcPtr, opcode, &p);
+ ForwardOpToHandlerThread(rcPtr, opcode, &p);
if (p.base.code != TCL_OK) {
Tcl_Obj *err = Tcl_NewStringObj(p.base.msgStr, -1);
@@ -2673,6 +2798,15 @@ DeleteThreadReflectedChannelMap(
Tcl_MutexUnlock(&rcForwardMutex);
/*
+ * Run over the event queue of this thread and remove all ReflectEvent's
+ * still pending. These are inbound events for reflected channels this
+ * thread owns but doesn't handle. The inverse of the channel map
+ * actually.
+ */
+
+ Tcl_DeleteEvents (ReflectEventDelete, NULL);
+
+ /*
* Get the map of all channels handled by the current thread. This is a
* ReflectedChannelMap, but on a per-thread basis, not per-interp. Go
* through the channels, remove all, mark them as dead.
@@ -2693,11 +2827,16 @@ DeleteThreadReflectedChannelMap(
}
static void
-ForwardOpToOwnerThread(
+ForwardOpToHandlerThread(
ReflectedChannel *rcPtr, /* Channel instance */
ForwardedOperation op, /* Forwarded driver operation */
const void *param) /* Arguments */
{
+ /*
+ * Core of the communication from OWNER to HANDLER thread.
+ * The receiver is ForwardProc() below.
+ */
+
Tcl_ThreadId dst = rcPtr->thread;
ForwardingEvent *evPtr;
ForwardingResult *resultPtr;
@@ -2750,7 +2889,7 @@ ForwardOpToOwnerThread(
/*
* Ensure cleanup of the event if the origin thread exits while this event
* is pending or in progress. Exit of the destination thread is handled by
- * DeleteThreadReflectionChannelMap(), this is set up by
+ * DeleteThreadReflectedChannelMap(), this is set up by
* GetThreadReflectedChannelMap(). This is what we use the 'forwardList'
* (see above) for.
*/
@@ -2765,7 +2904,7 @@ ForwardOpToOwnerThread(
Tcl_ThreadAlert(dst);
/*
- * (*) Block until the other thread has either processed the transfer or
+ * (*) Block until the handler thread has either processed the transfer or
* rejected it.
*/
@@ -2813,6 +2952,11 @@ ForwardProc(
int mask)
{
/*
+ * HANDLER thread.
+
+ * The receiver part for the operations coming from the OWNER thread.
+ * See ForwardOpToHandlerThread() for the transmitter.
+ *
* Notes regarding access to the referenced data.
*
* In principle the data belongs to the originating thread (see