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authorjan.nijtmans <nijtmans@users.sourceforge.net>2013-07-25 07:02:59 (GMT)
committerjan.nijtmans <nijtmans@users.sourceforge.net>2013-07-25 07:02:59 (GMT)
commit420d55eddd9dfa6bfce1d6977a83e8f97ff4a8e7 (patch)
treeb501748fb15ab8ff53d622fe8d36477988f9e36e /unix/tclUnixNotfy.c
parent7682f9c4cd7dfb3439a27d03b4531358798ff443 (diff)
parenta16e39b06e99f4b423262bc6330d8574efecc94d (diff)
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rebase
Diffstat (limited to 'unix/tclUnixNotfy.c')
-rw-r--r--unix/tclUnixNotfy.c117
1 files changed, 113 insertions, 4 deletions
diff --git a/unix/tclUnixNotfy.c b/unix/tclUnixNotfy.c
index 51f0b1f..f414c3f 100644
--- a/unix/tclUnixNotfy.c
+++ b/unix/tclUnixNotfy.c
@@ -112,7 +112,7 @@ typedef struct ThreadSpecificData {
int eventReady; /* True if an event is ready to be processed.
* Used as condition flag together with waitCV
* above. */
-#endif
+#endif /* TCL_THREADS */
} ThreadSpecificData;
static Tcl_ThreadDataKey dataKey;
@@ -128,6 +128,15 @@ static Tcl_ThreadDataKey dataKey;
static int notifierCount = 0;
/*
+ * The following static stores the process ID of the initialized notifier
+ * thread. If it changes, we have passed a fork and we should start a new
+ * notifier thread.
+ *
+ * You must hold the notifierMutex lock before accessing this variable.
+ */
+static pid_t processIDInitialized = 0;
+
+/*
* The following variable points to the head of a doubly-linked list of
* ThreadSpecificData structures for all threads that are currently waiting on
* an event.
@@ -185,7 +194,7 @@ static Tcl_Condition notifierCV;
static Tcl_ThreadId notifierThread;
-#endif
+#endif /* TCL_THREADS */
/*
* Static routines defined in this file.
@@ -193,7 +202,13 @@ static Tcl_ThreadId notifierThread;
#ifdef TCL_THREADS
static void NotifierThreadProc(ClientData clientData);
-#endif
+#ifdef HAVE_PTHREAD_ATFORK
+static int atForkInit = 0;
+static void AtForkPrepare(void);
+static void AtForkParent(void);
+static void AtForkChild(void);
+#endif /* HAVE_PTHREAD_ATFORK */
+#endif /* TCL_THREADS */
static int FileHandlerEventProc(Tcl_Event *evPtr, int flags);
/*
@@ -267,11 +282,38 @@ Tcl_InitNotifier(void)
*/
Tcl_MutexLock(&notifierMutex);
+#ifdef HAVE_PTHREAD_ATFORK
+ /*
+ * Install pthread_atfork handlers to reinitialize the notifier in the
+ * child of a fork.
+ */
+
+ if (!atForkInit) {
+ int result = pthread_atfork(AtForkPrepare, AtForkParent, AtForkChild);
+
+ if (result) {
+ Tcl_Panic("Tcl_InitNotifier: pthread_atfork failed");
+ }
+ atForkInit = 1;
+ }
+#endif
+ /*
+ * Check if my process id changed, e.g. I was forked
+ * In this case, restart the notifier thread and close the
+ * pipe to the original notifier thread
+ */
+ if (notifierCount > 0 && processIDInitialized != getpid()) {
+ notifierCount = 0;
+ processIDInitialized = 0;
+ close(triggerPipe);
+ triggerPipe = -1;
+ }
if (notifierCount == 0) {
if (TclpThreadCreate(&notifierThread, NotifierThreadProc, NULL,
TCL_THREAD_STACK_DEFAULT, TCL_THREAD_JOINABLE) != TCL_OK) {
Tcl_Panic("Tcl_InitNotifier: unable to start notifier thread");
}
+ processIDInitialized = getpid();
}
notifierCount++;
@@ -284,7 +326,7 @@ Tcl_InitNotifier(void)
}
Tcl_MutexUnlock(&notifierMutex);
-#endif
+#endif /* TCL_THREADS */
return (ClientData) tsdPtr;
}
@@ -1230,6 +1272,73 @@ NotifierThreadProc(
TclpThreadExit (0);
}
+
+#ifdef HAVE_PTHREAD_ATFORK
+/*
+ *----------------------------------------------------------------------
+ *
+ * AtForkPrepare --
+ *
+ * Lock the notifier in preparation for a fork.
+ *
+ * Results:
+ * None.
+ *
+ * Side effects:
+ * None.
+ *
+ *----------------------------------------------------------------------
+ */
+
+static void
+AtForkPrepare(void)
+{
+}
+
+/*
+ *----------------------------------------------------------------------
+ *
+ * AtForkParent --
+ *
+ * Unlock the notifier in the parent after a fork.
+ *
+ * Results:
+ * None.
+ *
+ * Side effects:
+ * None.
+ *
+ *----------------------------------------------------------------------
+ */
+
+static void
+AtForkParent(void)
+{
+}
+
+/*
+ *----------------------------------------------------------------------
+ *
+ * AtForkChild --
+ *
+ * Unlock and reinstall the notifier in the child after a fork.
+ *
+ * Results:
+ * None.
+ *
+ * Side effects:
+ * None.
+ *
+ *----------------------------------------------------------------------
+ */
+
+static void
+AtForkChild(void)
+{
+ Tcl_InitNotifier();
+}
+#endif /* HAVE_PTHREAD_ATFORK */
+
#endif /* TCL_THREADS */
#endif /* HAVE_COREFOUNDATION */