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-rw-r--r--win/tclWinChan.c75
1 files changed, 53 insertions, 22 deletions
diff --git a/win/tclWinChan.c b/win/tclWinChan.c
index d2f0fa1..be6ffe0 100644
--- a/win/tclWinChan.c
+++ b/win/tclWinChan.c
@@ -9,7 +9,7 @@
* See the file "license.terms" for information on usage and redistribution
* of this file, and for a DISCLAIMER OF ALL WARRANTIES.
*
- * RCS: @(#) $Id: tclWinChan.c,v 1.12 2000/09/28 06:38:23 hobbs Exp $
+ * RCS: @(#) $Id: tclWinChan.c,v 1.13 2000/10/06 23:46:06 davidg Exp $
*/
#include "tclWinInt.h"
@@ -879,16 +879,21 @@ Tcl_MakeFileChannel(rawHandle, mode)
char channelName[16 + TCL_INTEGER_SPACE];
Tcl_Channel channel = NULL;
HANDLE handle = (HANDLE) rawHandle;
+ HANDLE dupedHandle;
DCB dcb;
- DWORD consoleParams;
- DWORD type;
+ DWORD consoleParams, type;
TclFile readFile = NULL;
TclFile writeFile = NULL;
+ BOOL result;
if (mode == 0) {
return NULL;
}
+ /*
+ * GetFileType() returns FILE_TYPE_UNKNOWN for invalid handles.
+ */
+
type = GetFileType(handle);
/*
@@ -930,19 +935,58 @@ Tcl_MakeFileChannel(rawHandle, mode)
case FILE_TYPE_DISK:
case FILE_TYPE_CHAR:
- case FILE_TYPE_UNKNOWN:
channel = TclWinOpenFileChannel(handle, channelName, mode, 0);
break;
+ case FILE_TYPE_UNKNOWN:
default:
/*
- * The handle is of an unknown type, probably /dev/nul equivalent
- * or possibly a closed handle.
+ * The handle is of an unknown type. Test the validity of this OS
+ * handle by duplicating it, then closing the dupe. The Win32 API
+ * doesn't provide an IsValidHandle() function, so we have to emulate
+ * it here. This test will not work on a console handle reliably,
+ * which is why we can't test every handle that comes into this
+ * function in this way.
+ */
+
+ result = DuplicateHandle(GetCurrentProcess(), handle,
+ GetCurrentProcess(), &dupedHandle, 0, FALSE,
+ DUPLICATE_SAME_ACCESS);
+
+ if (result != 0) {
+ /*
+ * Unable to make a duplicate. It's definately invalid at this
+ * point.
+ */
+
+ return NULL;
+ }
+
+ /*
+ * Use structured exception handling (Win32 SEH) to protect the close
+ * of this duped handle which might throw EXCEPTION_INVALID_HANDLE.
*/
-
- channel = NULL;
- break;
+ __try {
+ CloseHandle(dupedHandle);
+ }
+ __except (EXCEPTION_EXECUTE_HANDLER) {
+ /*
+ * Definately an invalid handle. So, therefore, the original
+ * is invalid also.
+ */
+
+ return NULL;
+ }
+
+ /* Fall through, the handle is valid. */
+
+ /*
+ * Create the undefined channel, anyways, because we know the handle
+ * is valid to something.
+ */
+
+ channel = TclWinOpenFileChannel(handle, channelName, mode, 0);
}
return channel;
@@ -974,8 +1018,6 @@ TclpGetDefaultStdChannel(type)
int mode;
char *bufMode;
DWORD handleId; /* Standard handle to retrieve. */
- char dummyBuff[1]; /* Buffer for the WriteFile test */
- DWORD dummyWritten; /* Required parameter for WriteFile */
switch (type) {
@@ -1011,17 +1053,6 @@ TclpGetDefaultStdChannel(type)
return (Tcl_Channel) NULL;
}
- /*
- * Win2K BUG: GetStdHandle(STD_OUTPUT_HANDLE) can return what appears
- * to be a valid handle. Do an extra test with WriteFile() "touching"
- * the handle.
- */
-
- if ((type == TCL_STDOUT)
- && !WriteFile(handle, dummyBuff, 0, &dummyWritten, NULL)) {
- return (Tcl_Channel) NULL;
- }
-
channel = Tcl_MakeFileChannel(handle, mode);
if (channel == NULL) {