From a43b4a80fa5e24ec35b325b0e5709033b40226e9 Mon Sep 17 00:00:00 2001
From: sebres <sebres@users.sourceforge.net>
Date: Tue, 31 Mar 2020 20:04:53 +0000
Subject: fixes [f583715154] - tclUnixSock.c: introduced ThreadActionProc
 considering a transfer of async-connecting channel between threads;
 cherry-picked some prevention against invalid thread owner addressed in
 [815e246806]

---
 generic/tclIO.c    | 26 ++++++++++++++++++++++++++
 unix/tclUnixSock.c | 49 ++++++++++++++++++++++++++++++++++++++++++++++++-
 2 files changed, 74 insertions(+), 1 deletion(-)

diff --git a/generic/tclIO.c b/generic/tclIO.c
index 67264a0..ab8d8ac 100644
--- a/generic/tclIO.c
+++ b/generic/tclIO.c
@@ -3189,6 +3189,9 @@ CutChannel(
      */
 
     ChanThreadAction((Channel *) chan, TCL_CHANNEL_THREAD_REMOVE);
+
+    /* Channel is not managed by any thread */
+    statePtr->managingThread = NULL;
 }
 
 void
@@ -3233,6 +3236,9 @@ Tcl_CutChannel(
     for (; chanPtr != NULL ; chanPtr = chanPtr->upChanPtr) {
 	ChanThreadAction(chanPtr, TCL_CHANNEL_THREAD_REMOVE);
     }
+
+    /* Channel is not managed by any thread */
+    statePtr->managingThread = NULL;
 }
 
 /*
@@ -8382,6 +8388,13 @@ Tcl_NotifyChannel(
     Tcl_Preserve(statePtr);
 
     /*
+     * Avoid processing if the channel owner has been changed.
+     */
+    if (statePtr->managingThread != Tcl_GetCurrentThread()) {
+	goto done;
+    }
+
+    /*
      * If we are flushing in the background, be sure to call FlushChannel for
      * writable events. Note that we have to discard the writable event so we
      * don't call any write handlers before the flush is complete.
@@ -8415,6 +8428,13 @@ Tcl_NotifyChannel(
 	} else {
 	    chPtr = chPtr->nextPtr;
 	}
+
+	/*
+	 * Stop if the channel owner has been changed in-between.
+	 */
+	if (chanPtr->state->managingThread != Tcl_GetCurrentThread()) {
+	    goto done;
+	}
     }
 
     /*
@@ -8432,6 +8452,7 @@ Tcl_NotifyChannel(
 	UpdateInterest(chanPtr);
     }
 
+done:
     Tcl_Release(statePtr);
     TclChannelRelease(channel);
 
@@ -8909,6 +8930,11 @@ TclChannelEventScriptInvoker(
     interp = esPtr->interp;
 
     /*
+     * Be sure event executed in managed channel (covering bugs similar [f583715154]).
+     */
+    assert(chanPtr->state->managingThread == Tcl_GetCurrentThread());
+
+    /*
      * We must preserve the interpreter so we can report errors on it later.
      * Note that we do not need to preserve the channel because that is done
      * by Tcl_NotifyChannel before calling channel handlers.
diff --git a/unix/tclUnixSock.c b/unix/tclUnixSock.c
index 1901c8b..4d7a8fb 100644
--- a/unix/tclUnixSock.c
+++ b/unix/tclUnixSock.c
@@ -118,6 +118,7 @@ struct TcpState {
  * Static routines for this file:
  */
 
+static void		TcpAsyncCallback(ClientData clientData, int mask);
 static int		TcpConnect(Tcl_Interp *interp, TcpState *state);
 static void		TcpAccept(ClientData data, int mask);
 static int		TcpBlockModeProc(ClientData data, int mode);
@@ -134,6 +135,7 @@ static int		TcpInputProc(ClientData instanceData, char *buf,
 			    int toRead, int *errorCode);
 static int		TcpOutputProc(ClientData instanceData,
 			    const char *buf, int toWrite, int *errorCode);
+static void		TcpThreadActionProc(ClientData instanceData, int action);
 static void		TcpWatchProc(ClientData instanceData, int mask);
 static int		WaitForConnect(TcpState *statePtr, int *errorCodePtr);
 static void		WrapNotify(ClientData clientData, int mask);
@@ -159,7 +161,7 @@ static const Tcl_ChannelType tcpChannelType = {
     NULL,			/* flush proc. */
     NULL,			/* handler proc. */
     NULL,			/* wide seek proc. */
-    NULL,			/* thread action proc. */
+    TcpThreadActionProc,	/* thread action proc. */
     NULL			/* truncate proc. */
 };
 
@@ -958,6 +960,51 @@ TcpGetOptionProc(
 /*
  * ----------------------------------------------------------------------
  *
+ * TcpThreadActionProc --
+ *
+ *	Handles detach/attach for asynchronously connecting socket.
+ *
+ *	Reassigning the file handler associated with thread-related channel
+ *	notification, responsible for callbacks (signaling that asynchronous
+ *	connection attempt has succeeded or failed).
+ *
+ * Results:
+ *	None.
+ *
+ * ----------------------------------------------------------------------
+ */
+
+static void
+TcpThreadActionProc(
+    ClientData instanceData,
+    int action)
+{
+    TcpState *statePtr = (TcpState *)instanceData;
+
+    if (GOT_BITS(statePtr->flags, TCP_ASYNC_CONNECT)) {
+	/*
+	 * Async-connecting socket must get reassigned handler if it have been
+	 * transferred to another thread. Remove the handler if the socket is 
+	 * not managed by this thread anymore and create new handler (TSD related)
+	 * so the callback will run in the correct thread, bug [f583715154].
+	 */
+	switch (action) {
+	  case TCL_CHANNEL_THREAD_REMOVE:
+	    CLEAR_BITS(statePtr->flags, TCP_ASYNC_PENDING);
+	    Tcl_DeleteFileHandler(statePtr->fds.fd);
+	  break;
+	  case TCL_CHANNEL_THREAD_INSERT:
+	    Tcl_CreateFileHandler(statePtr->fds.fd,
+		TCL_WRITABLE | TCL_EXCEPTION, TcpAsyncCallback, statePtr);
+	    SET_BITS(statePtr->flags, TCP_ASYNC_PENDING);
+	  break;
+	}
+    }
+}
+
+/*
+ * ----------------------------------------------------------------------
+ *
  * TcpWatchProc --
  *
  *	Initialize the notifier to watch the fd from this channel.
-- 
cgit v0.12