diff options
| -rw-r--r-- | win/tclWinChan.c | 75 |
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) { |