1 files changed, 101 insertions, 2 deletions

diff --git a/win/tclWinChan.c b/win/tclWinChan.c
index 21115f7..c63aaa7 100644
--- a/win/tclWinChan.c
+++ b/win/tclWinChan.c
@@ -95,7 +95,7 @@ static void		FileThreadActionProc(ClientData instanceData,
 static int		FileTruncateProc(ClientData instanceData,
 			    Tcl_WideInt length);
 static DWORD		FileGetType(HANDLE handle);
-
+static int		NativeIsComPort(CONST TCHAR *nativeName);
 /*
  * This structure describes the channel type structure for file based IO.
  */
@@ -885,6 +885,33 @@ TclpOpenFileChannel(
     }
 
     /*
+     * [2413550] Avoid double-open of serial ports on Windows
+     * Special handling for Windows serial ports by a "name-hint"
+     * to directly open it with the OVERLAPPED flag set.
+     */
+
+    if( NativeIsComPort(nativeName) ) {
+
+	handle = TclWinSerialOpen(INVALID_HANDLE_VALUE, nativeName, accessMode);
+	if (handle == INVALID_HANDLE_VALUE) {
+	    TclWinConvertError(GetLastError());
+	    if (interp != (Tcl_Interp *) NULL) {
+		Tcl_AppendResult(interp, "couldn't open serial \"",
+			TclGetString(pathPtr), "\": ",
+			Tcl_PosixError(interp), NULL);
+	    }
+	    return NULL;
+	}
+
+	/*
+	* For natively named Windows serial ports we are done.
+	*/
+	channel = TclWinOpenSerialChannel(handle, channelName,
+		channelPermissions);
+
+	return channel;
+    }
+    /*
      * If the file is being created, get the file attributes from the
      * permissions argument, else use the existing file attributes.
      */
@@ -935,11 +962,15 @@ TclpOpenFileChannel(
     switch (FileGetType(handle)) {
     case FILE_TYPE_SERIAL:
 	/*
+	 * Natively named serial ports "com1-9", "\\\\.\\comXX" are 
+	 * already done with the code above.
+	 * Here we handle all other serial port names.
+	 *
 	 * Reopen channel for OVERLAPPED operation. Normally this shouldn't
 	 * fail, because the channel exists.
 	 */
 
-	handle = TclWinSerialReopen(handle, nativeName, accessMode);
+	handle = TclWinSerialOpen(handle, nativeName, accessMode);
 	if (handle == INVALID_HANDLE_VALUE) {
 	    TclWinConvertError(GetLastError());
 	    if (interp != (Tcl_Interp *) NULL) {
@@ -1479,6 +1510,74 @@ FileGetType(
     return type;
 }
 
+ /*
+ *----------------------------------------------------------------------
+ *
+ * NativeIsComPort --
+ *
+ *	Determines if a path refers to a Windows serial port.
+ *	A simple and efficient solution is to use a "name hint" to detect 
+ *      COM ports by their filename instead of resorting to a syscall 
+ *	to detect serialness after the fact.
+ *	The following patterns cover common serial port names:
+ *	    COM[1-9]:?
+ *	    //./COM[0-9]+
+ *	    \\.\COM[0-9]+
+ *
+ * Results:
+ *	1 = serial port, 0 = not.
+ *
+ *----------------------------------------------------------------------
+ */
+
+static int
+NativeIsComPort(
+    const TCHAR *nativePath)	/* Path of file to access, native encoding. */
+{
+    const WCHAR *p = (const WCHAR *) nativePath;
+    int i, len = wcslen(p);
+
+    /*
+     * 1. Look for com[1-9]:?
+     */
+
+    if ( (len >= 4) && (len <= 5) 
+	    && (_wcsnicmp(p, L"com", 3) == 0) ) {
+	/*
+	* The 4th character must be a digit 1..9 optionally followed by a ":"
+	*/
+	
+	if ( (p[3] < L'1') || (p[3] > L'9') ) {
+	    return 0;
+	}
+	if ( (len == 5) && (p[4] != L':') ) {
+	    return 0;
+	}
+	return 1;
+    }
+    
+    /*
+     * 2. Look for //./com[0-9]+ or \\.\com[0-9]+
+     */
+    
+    if ( (len >= 8) && ( 
+	       (_wcsnicmp(p, L"//./com", 7) == 0)
+	    || (_wcsnicmp(p, L"\\\\.\\com", 7) == 0) ) )
+    {
+	/*
+	* Charaters 8..end must be a digits 0..9
+	*/
+    
+	for ( i=7; i<len; i++ ) {
+	    if ( (p[i] < '0') || (p[i] > '9') ) {
+		return 0;
+	    }
+	}
+	return 1;
+    }
+    return 0;
+}
+
 /*
  * Local Variables:
  * mode: c