/* 

  * tclWinChan.c

  *

  *	Channel drivers for Windows channels based on files, command

  *	pipes and TCP sockets.

  *

  * Copyright (c) 1995-1997 Sun Microsystems, Inc.

  *

  * 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 1.30.2.5 2006/08/30 17:53:28 hobbs Exp $

  */

 #include "tclWinInt.h"

 #include "tclIO.h"

 /*

  * State flags used in the info structures below.

  */

 #define FILE_PENDING	(1<<0)	/* Message is pending in the queue. */

 #define FILE_ASYNC	(1<<1)	/* Channel is non-blocking. */

 #define FILE_APPEND	(1<<2)	/* File is in append mode. */

 #define FILE_TYPE_SERIAL  (FILE_TYPE_PIPE+1)

 #define FILE_TYPE_CONSOLE (FILE_TYPE_PIPE+2)

 /*

  * The following structure contains per-instance data for a file based channel.

  */

 typedef struct FileInfo {

     Tcl_Channel channel;	/* Pointer to channel structure. */

     int validMask;		/* OR'ed combination of TCL_READABLE,

 				 * TCL_WRITABLE, or TCL_EXCEPTION: indicates

 				 * which operations are valid on the file. */

     int watchMask;		/* OR'ed combination of TCL_READABLE,

 				 * TCL_WRITABLE, or TCL_EXCEPTION: indicates

 				 * which events should be reported. */

     int flags;			/* State flags, see above for a list. */

     HANDLE handle;		/* Input/output file. */

     struct FileInfo *nextPtr;	/* Pointer to next registered file. */

     int dirty;                  /* Boolean flag. Set if the OS may have data

 				 * pending on the channel */

 } FileInfo;

 typedef struct ThreadSpecificData {

     /*

      * List of all file channels currently open.

      */

     FileInfo *firstFilePtr;

 } ThreadSpecificData;

 static Tcl_ThreadDataKey dataKey;

 /*

  * The following structure is what is added to the Tcl event queue when

  * file events are generated.

  */

 typedef struct FileEvent {

     Tcl_Event header;		/* Information that is standard for

 				 * all events. */

     FileInfo *infoPtr;		/* Pointer to file info structure.  Note

 				 * that we still have to verify that the

 				 * file exists before dereferencing this

 				 * pointer. */

 } FileEvent;

 /*

  * Static routines for this file:

  */

 static int		FileBlockProc _ANSI_ARGS_((ClientData instanceData,

 			    int mode));

 static void		FileChannelExitHandler _ANSI_ARGS_((

 		            ClientData clientData));

 static void		FileCheckProc _ANSI_ARGS_((ClientData clientData,

 			    int flags));

 static int		FileCloseProc _ANSI_ARGS_((ClientData instanceData,

 		            Tcl_Interp *interp));

 static int		FileEventProc _ANSI_ARGS_((Tcl_Event *evPtr, 

 			    int flags));

 static int		FileGetHandleProc _ANSI_ARGS_((ClientData instanceData,

 		            int direction, ClientData *handlePtr));

 static ThreadSpecificData *FileInit _ANSI_ARGS_((void));

 static int		FileInputProc _ANSI_ARGS_((ClientData instanceData,

 	            	    char *buf, int toRead, int *errorCode));

 static int		FileOutputProc _ANSI_ARGS_((ClientData instanceData,

 			    CONST char *buf, int toWrite, int *errorCode));

 static int		FileSeekProc _ANSI_ARGS_((ClientData instanceData,

 			    long offset, int mode, int *errorCode));

 static Tcl_WideInt	FileWideSeekProc _ANSI_ARGS_((ClientData instanceData,

 			    Tcl_WideInt offset, int mode, int *errorCode));

 static void		FileSetupProc _ANSI_ARGS_((ClientData clientData,

 			    int flags));

 static void		FileWatchProc _ANSI_ARGS_((ClientData instanceData,

 		            int mask));

 static void             FileThreadActionProc _ANSI_ARGS_ ((

 			   ClientData instanceData, int action));

 static DWORD		FileGetType _ANSI_ARGS_((HANDLE handle));

 /*

  * This structure describes the channel type structure for file based IO.

  */

 static Tcl_ChannelType fileChannelType = {

     "file",			/* Type name. */

     TCL_CHANNEL_VERSION_4,	/* v4 channel */

     FileCloseProc,		/* Close proc. */

     FileInputProc,		/* Input proc. */

     FileOutputProc,		/* Output proc. */

     FileSeekProc,		/* Seek proc. */

     NULL,			/* Set option proc. */

     NULL,			/* Get option proc. */

     FileWatchProc,		/* Set up the notifier to watch the channel. */

     FileGetHandleProc,		/* Get an OS handle from channel. */

     NULL,			/* close2proc. */

     FileBlockProc,		/* Set blocking or non-blocking mode.*/

     NULL,			/* flush proc. */

     NULL,			/* handler proc. */

     FileWideSeekProc,		/* Wide seek proc. */

     FileThreadActionProc,	/* Thread action proc. */

 };

 #ifdef HAVE_NO_SEH

 /*

  * Unlike Borland and Microsoft, we don't register exception handlers

  * by pushing registration records onto the runtime stack.  Instead, we

  * register them by creating an EXCEPTION_REGISTRATION within the activation

  * record.

  */

 typedef struct EXCEPTION_REGISTRATION {

     struct EXCEPTION_REGISTRATION* link;

     EXCEPTION_DISPOSITION (*handler)( struct _EXCEPTION_RECORD*, void*,

 				      struct _CONTEXT*, void* );

     void* ebp;

     void* esp;

     int status;

 } EXCEPTION_REGISTRATION;

 #endif

 /*

  *----------------------------------------------------------------------

  *

  * FileInit --

  *

  *	This function creates the window used to simulate file events.

  *

  * Results:

  *	None.

  *

  * Side effects:

  *	Creates a new window and creates an exit handler. 

  *

  *----------------------------------------------------------------------

  */

 static ThreadSpecificData *

 FileInit()

 {

     ThreadSpecificData *tsdPtr =

 	(ThreadSpecificData *)TclThreadDataKeyGet(&dataKey);

     if (tsdPtr == NULL) {

 	tsdPtr = TCL_TSD_INIT(&dataKey);

 	tsdPtr->firstFilePtr = NULL;

 	Tcl_CreateEventSource(FileSetupProc, FileCheckProc, NULL);

 	Tcl_CreateThreadExitHandler(FileChannelExitHandler, NULL);

     }

     return tsdPtr;

 }

 /*

  *----------------------------------------------------------------------

  *

  * FileChannelExitHandler --

  *

  *	This function is called to cleanup the channel driver before

  *	Tcl is unloaded.

  *

  * Results:

  *	None.

  *

  * Side effects:

  *	Destroys the communication window.

  *

  *----------------------------------------------------------------------

  */

 static void

 FileChannelExitHandler(clientData)

     ClientData clientData;	/* Old window proc */

 {

     Tcl_DeleteEventSource(FileSetupProc, FileCheckProc, NULL);

 }

 /*

  *----------------------------------------------------------------------

  *

  * FileSetupProc --

  *

  *	This procedure is invoked before Tcl_DoOneEvent blocks waiting

  *	for an event.

  *

  * Results:

  *	None.

  *

  * Side effects:

  *	Adjusts the block time if needed.

  *

  *----------------------------------------------------------------------

  */

 void

 FileSetupProc(data, flags)

     ClientData data;		/* Not used. */

     int flags;			/* Event flags as passed to Tcl_DoOneEvent. */

 {

     FileInfo *infoPtr;

     Tcl_Time blockTime = { 0, 0 };

     ThreadSpecificData *tsdPtr = TCL_TSD_INIT(&dataKey);

     if (!(flags & TCL_FILE_EVENTS)) {

 	return;

     }

     /*

      * Check to see if there is a ready file.  If so, poll.

      */

     for (infoPtr = tsdPtr->firstFilePtr; infoPtr != NULL; 

 	    infoPtr = infoPtr->nextPtr) {

 	if (infoPtr->watchMask) {

 	    Tcl_SetMaxBlockTime(&blockTime);

 	    break;

 	}

     }

 }

 /*

  *----------------------------------------------------------------------

  *

  * FileCheckProc --

  *

  *	This procedure is called by Tcl_DoOneEvent to check the file

  *	event source for events. 

  *

  * Results:

  *	None.

  *

  * Side effects:

  *	May queue an event.

  *

  *----------------------------------------------------------------------

  */

 static void

 FileCheckProc(data, flags)

     ClientData data;		/* Not used. */

     int flags;			/* Event flags as passed to Tcl_DoOneEvent. */

 {

     FileEvent *evPtr;

     FileInfo *infoPtr;

     ThreadSpecificData *tsdPtr = TCL_TSD_INIT(&dataKey);

     if (!(flags & TCL_FILE_EVENTS)) {

 	return;

     }

     /*

      * Queue events for any ready files that don't already have events

      * queued (caused by persistent states that won't generate WinSock

      * events).

      */

     for (infoPtr = tsdPtr->firstFilePtr; infoPtr != NULL; 

 	    infoPtr = infoPtr->nextPtr) {

 	if (infoPtr->watchMask && !(infoPtr->flags & FILE_PENDING)) {

 	    infoPtr->flags |= FILE_PENDING;

 	    evPtr = (FileEvent *) ckalloc(sizeof(FileEvent));

 	    evPtr->header.proc = FileEventProc;

 	    evPtr->infoPtr = infoPtr;

 	    Tcl_QueueEvent((Tcl_Event *) evPtr, TCL_QUEUE_TAIL);

 	}

     }

 }

 /*----------------------------------------------------------------------

  *

  * FileEventProc --

  *

  *	This function is invoked by Tcl_ServiceEvent when a file event

  *	reaches the front of the event queue.  This procedure invokes

  *	Tcl_NotifyChannel on the file.

  *

  * Results:

  *	Returns 1 if the event was handled, meaning it should be removed

  *	from the queue.  Returns 0 if the event was not handled, meaning

  *	it should stay on the queue.  The only time the event isn't

  *	handled is if the TCL_FILE_EVENTS flag bit isn't set.

  *

  * Side effects:

  *	Whatever the notifier callback does.

  *

  *----------------------------------------------------------------------

  */

 static int

 FileEventProc(evPtr, flags)

     Tcl_Event *evPtr;		/* Event to service. */

     int flags;			/* Flags that indicate what events to

 				 * handle, such as TCL_FILE_EVENTS. */

 {

     FileEvent *fileEvPtr = (FileEvent *)evPtr;

     FileInfo *infoPtr;

     ThreadSpecificData *tsdPtr = TCL_TSD_INIT(&dataKey);

     if (!(flags & TCL_FILE_EVENTS)) {

 	return 0;

     }

     /*

      * Search through the list of watched files for the one whose handle

      * matches the event.  We do this rather than simply dereferencing

      * the handle in the event so that files can be deleted while the

      * event is in the queue.

      */

     for (infoPtr = tsdPtr->firstFilePtr; infoPtr != NULL;

 	    infoPtr = infoPtr->nextPtr) {

 	if (fileEvPtr->infoPtr == infoPtr) {

 	    infoPtr->flags &= ~(FILE_PENDING);

 	    Tcl_NotifyChannel(infoPtr->channel, infoPtr->watchMask);

 	    break;

 	}

     }

     return 1;

 }

 /*

  *----------------------------------------------------------------------

  *

  * FileBlockProc --

  *

  *	Set blocking or non-blocking mode on channel.

  *

  * Results:

  *	0 if successful, errno when failed.

  *

  * Side effects:

  *	Sets the device into blocking or non-blocking mode.

  *

  *----------------------------------------------------------------------

  */

 static int

 FileBlockProc(instanceData, mode)

     ClientData instanceData;	/* Instance data for channel. */

     int mode;			/* TCL_MODE_BLOCKING or

                                  * TCL_MODE_NONBLOCKING. */

 {

     FileInfo *infoPtr = (FileInfo *) instanceData;

     /*

      * Files on Windows can not be switched between blocking and nonblocking,

      * hence we have to emulate the behavior. This is done in the input

      * function by checking against a bit in the state. We set or unset the

      * bit here to cause the input function to emulate the correct behavior.

      */

     if (mode == TCL_MODE_NONBLOCKING) {

 	infoPtr->flags |= FILE_ASYNC;

     } else {

 	infoPtr->flags &= ~(FILE_ASYNC);

     }

     return 0;

 }

 /*

  *----------------------------------------------------------------------

  *

  * FileCloseProc --

  *

  *	Closes the IO channel.

  *

  * Results:

  *	0 if successful, the value of errno if failed.

  *

  * Side effects:

  *	Closes the physical channel

  *

  *----------------------------------------------------------------------

  */

 static int

 FileCloseProc(instanceData, interp)

     ClientData instanceData;	/* Pointer to FileInfo structure. */

     Tcl_Interp *interp;		/* Not used. */

 {

     FileInfo *fileInfoPtr = (FileInfo *) instanceData;

     FileInfo *infoPtr;

     ThreadSpecificData *tsdPtr;

     int errorCode = 0;

     /*

      * Remove the file from the watch list.

      */

     FileWatchProc(instanceData, 0);

     /*

      * Don't close the Win32 handle if the handle is a standard channel

      * during the thread exit process.  Otherwise, one thread may kill

      * the stdio of another.

      */

     if (!TclInThreadExit() 

 	    || ((GetStdHandle(STD_INPUT_HANDLE) != fileInfoPtr->handle)

 		&& (GetStdHandle(STD_OUTPUT_HANDLE) != fileInfoPtr->handle)

 		&& (GetStdHandle(STD_ERROR_HANDLE) != fileInfoPtr->handle))) {

 	if (CloseHandle(fileInfoPtr->handle) == FALSE) {

 	    TclWinConvertError(GetLastError());

 	    errorCode = errno;

 	}

     }

     /*

      * See if this FileInfo* is still on the thread local list.

      */

     tsdPtr = TCL_TSD_INIT(&dataKey);

     for (infoPtr = tsdPtr->firstFilePtr; infoPtr != NULL; 

 	    infoPtr = infoPtr->nextPtr) {

 	if (infoPtr == fileInfoPtr) {

             /*

              * This channel exists on the thread local list. It should

              * have been removed by an earlier Thread Action call,

              * but do that now since just deallocating fileInfoPtr would

              * leave an deallocated pointer on the thread local list.

              */

 	    FileThreadActionProc(fileInfoPtr,TCL_CHANNEL_THREAD_REMOVE);

             break;

         }

     }

     ckfree((char *)fileInfoPtr);

     return errorCode;

 }

 /*

  *----------------------------------------------------------------------

  *

  * FileSeekProc --

  *

  *	Seeks on a file-based channel. Returns the new position.

  *

  * Results:

  *	-1 if failed, the new position if successful. If failed, it

  *	also sets *errorCodePtr to the error code.

  *

  * Side effects:

  *	Moves the location at which the channel will be accessed in

  *	future operations.

  *

  *----------------------------------------------------------------------

  */

 static int

 FileSeekProc(instanceData, offset, mode, errorCodePtr)

     ClientData instanceData;	/* File state. */

     long offset;		/* Offset to seek to. */

     int mode;			/* Relative to where should we seek? */

     int *errorCodePtr;		/* To store error code. */

 {

     FileInfo *infoPtr = (FileInfo *) instanceData;

     DWORD moveMethod;

     DWORD newPos, newPosHigh;

     DWORD oldPos, oldPosHigh;

     *errorCodePtr = 0;

     if (mode == SEEK_SET) {

         moveMethod = FILE_BEGIN;

     } else if (mode == SEEK_CUR) {

         moveMethod = FILE_CURRENT;

     } else {

         moveMethod = FILE_END;

     }

     /*

      * Save our current place in case we need to roll-back the seek.

      */

     oldPosHigh = (DWORD)0;

     oldPos = SetFilePointer(infoPtr->handle, (LONG)0, &oldPosHigh,

 	    FILE_CURRENT);

     if (oldPos == INVALID_SET_FILE_POINTER) {

 	DWORD winError = GetLastError();

 	if (winError != NO_ERROR) {

 	    TclWinConvertError(winError);

 	    *errorCodePtr = errno;

 	    return -1;

 	}

     }

     newPosHigh = (DWORD)(offset < 0 ? -1 : 0);

     newPos = SetFilePointer(infoPtr->handle, (LONG) offset, &newPosHigh,

 			    moveMethod);

     if (newPos == INVALID_SET_FILE_POINTER) {

 	DWORD winError = GetLastError();

 	if (winError != NO_ERROR) {

 	    TclWinConvertError(winError);

 	    *errorCodePtr = errno;

 	    return -1;

 	}

     }

     /*

      * Check for expressability in our return type, and roll-back otherwise.

      */

     if (newPosHigh != 0) {

 	*errorCodePtr = EOVERFLOW;

 	SetFilePointer(infoPtr->handle, (LONG)oldPos, &oldPosHigh, FILE_BEGIN);

 	return -1;

     }

     return (int) newPos;

 }

 /*

  *----------------------------------------------------------------------

  *

  * FileWideSeekProc --

  *

  *	Seeks on a file-based channel. Returns the new position.

  *

  * Results:

  *	-1 if failed, the new position if successful. If failed, it

  *	also sets *errorCodePtr to the error code.

  *

  * Side effects:

  *	Moves the location at which the channel will be accessed in

  *	future operations.

  *

  *----------------------------------------------------------------------

  */

 static Tcl_WideInt

 FileWideSeekProc(instanceData, offset, mode, errorCodePtr)

     ClientData instanceData;	/* File state. */

     Tcl_WideInt offset;		/* Offset to seek to. */

     int mode;			/* Relative to where should we seek? */

     int *errorCodePtr;		/* To store error code. */

 {

     FileInfo *infoPtr = (FileInfo *) instanceData;

     DWORD moveMethod;

     DWORD newPos, newPosHigh;

     *errorCodePtr = 0;

     if (mode == SEEK_SET) {

         moveMethod = FILE_BEGIN;

     } else if (mode == SEEK_CUR) {

         moveMethod = FILE_CURRENT;

     } else {

         moveMethod = FILE_END;

     }

     newPosHigh = (DWORD)(offset >> 32);

     newPos = SetFilePointer(infoPtr->handle, (LONG) offset, &newPosHigh,

 			    moveMethod);

     if (newPos == INVALID_SET_FILE_POINTER) {

 	DWORD winError = GetLastError();

 	if (winError != NO_ERROR) {

 	    TclWinConvertError(winError);

 	    *errorCodePtr = errno;

 	    return -1;

 	}

     }

     return ((Tcl_WideInt) newPos) | (((Tcl_WideInt) newPosHigh) << 32);

 }

 /*

  *----------------------------------------------------------------------

  *

  * FileInputProc --

  *

  *	Reads input from the IO channel into the buffer given. Returns

  *	count of how many bytes were actually read, and an error indication.

  *

  * Results:

  *	A count of how many bytes were read is returned and an error

  *	indication is returned in an output argument.

  *

  * Side effects:

  *	Reads input from the actual channel.

  *

  *----------------------------------------------------------------------

  */

 static int

 FileInputProc(instanceData, buf, bufSize, errorCode)

     ClientData instanceData;		/* File state. */

     char *buf;				/* Where to store data read. */

     int bufSize;			/* How much space is available

                                          * in the buffer? */

     int *errorCode;			/* Where to store error code. */

 {

     FileInfo *infoPtr;

     DWORD bytesRead;

     *errorCode = 0;

     infoPtr = (FileInfo *) instanceData;

     /*

      * Note that we will block on reads from a console buffer until a

      * full line has been entered.  The only way I know of to get

      * around this is to write a console driver.  We should probably

      * do this at some point, but for now, we just block.  The same

      * problem exists for files being read over the network.

      */

     if (ReadFile(infoPtr->handle, (LPVOID) buf, (DWORD) bufSize, &bytesRead,

             (LPOVERLAPPED) NULL) != FALSE) {

 	return bytesRead;

     }

     TclWinConvertError(GetLastError());

     *errorCode = errno;

     if (errno == EPIPE) {

 	return 0;

     }

     return -1;

 }

 /*

  *----------------------------------------------------------------------

  *

  * FileOutputProc --

  *

  *	Writes the given output on the IO channel. Returns count of how

  *	many characters were actually written, and an error indication.

  *

  * Results:

  *	A count of how many characters were written is returned and an

  *	error indication is returned in an output argument.

  *

  * Side effects:

  *	Writes output on the actual channel.

  *

  *----------------------------------------------------------------------

  */

 static int

 FileOutputProc(instanceData, buf, toWrite, errorCode)

     ClientData instanceData;		/* File state. */

     CONST char *buf;			/* The data buffer. */

     int toWrite;			/* How many bytes to write? */

     int *errorCode;			/* Where to store error code. */

 {

     FileInfo *infoPtr = (FileInfo *) instanceData;

     DWORD bytesWritten;

     *errorCode = 0;

     /*

      * If we are writing to a file that was opened with O_APPEND, we need to

      * seek to the end of the file before writing the current buffer.

      */

     if (infoPtr->flags & FILE_APPEND) {

         SetFilePointer(infoPtr->handle, 0, NULL, FILE_END);

     }

     if (WriteFile(infoPtr->handle, (LPVOID) buf, (DWORD) toWrite, &bytesWritten,

             (LPOVERLAPPED) NULL) == FALSE) {

         TclWinConvertError(GetLastError());

         *errorCode = errno;

         return -1;

     }

     infoPtr->dirty = 1;

     return bytesWritten;

 }

 /*

  *----------------------------------------------------------------------

  *

  * FileWatchProc --

  *

  *	Called by the notifier to set up to watch for events on this

  *	channel.

  *

  * Results:

  *	None.

  *

  * Side effects:

  *	None.

  *

  *----------------------------------------------------------------------

  */

 static void

 FileWatchProc(instanceData, mask)

     ClientData instanceData;		/* File state. */

     int mask;				/* What events to watch for; OR-ed

                                          * combination of TCL_READABLE,

                                          * TCL_WRITABLE and TCL_EXCEPTION. */

 {

     FileInfo *infoPtr = (FileInfo *) instanceData;

     Tcl_Time blockTime = { 0, 0 };

     /*

      * Since the file is always ready for events, we set the block time

      * to zero so we will poll.

      */

     infoPtr->watchMask = mask & infoPtr->validMask;

     if (infoPtr->watchMask) {

 	Tcl_SetMaxBlockTime(&blockTime);

     }

 }

 /*

  *----------------------------------------------------------------------

  *

  * FileGetHandleProc --

  *

  *	Called from Tcl_GetChannelHandle to retrieve OS handles from

  *	a file based channel.

  *

  * Results:

  *	Returns TCL_OK with the fd in handlePtr, or TCL_ERROR if

  *	there is no handle for the specified direction. 

  *

  * Side effects:

  *	None.

  *

  *----------------------------------------------------------------------

  */

 static int

 FileGetHandleProc(instanceData, direction, handlePtr)

     ClientData instanceData;	/* The file state. */

     int direction;		/* TCL_READABLE or TCL_WRITABLE */

     ClientData *handlePtr;	/* Where to store the handle.  */

 {

     FileInfo *infoPtr = (FileInfo *) instanceData;

     if (direction & infoPtr->validMask) {

 	*handlePtr = (ClientData) infoPtr->handle;

 	return TCL_OK;

     } else {

 	return TCL_ERROR;

     }

 }

 /*

  *----------------------------------------------------------------------

  *

  * TclpOpenFileChannel --

  *

  *	Open an File based channel on Unix systems.

  *

  * Results:

  *	The new channel or NULL. If NULL, the output argument

  *	errorCodePtr is set to a POSIX error.

  *

  * Side effects:

  *	May open the channel and may cause creation of a file on the

  *	file system.

  *

  *----------------------------------------------------------------------

  */

 Tcl_Channel

 TclpOpenFileChannel(interp, pathPtr, mode, permissions)

     Tcl_Interp *interp;			/* Interpreter for error reporting;

                                          * can be NULL. */

     Tcl_Obj *pathPtr;			/* Name of file to open. */

     int mode;				/* POSIX mode. */

     int permissions;			/* If the open involves creating a

                                          * file, with what modes to create

                                          * it? */

 {

     Tcl_Channel channel = 0;

     int channelPermissions;

     DWORD accessMode, createMode, shareMode, flags;

     CONST TCHAR *nativeName;

     HANDLE handle;

     char channelName[16 + TCL_INTEGER_SPACE];

     TclFile readFile = NULL;

     TclFile writeFile = NULL;

     nativeName = (TCHAR*) Tcl_FSGetNativePath(pathPtr);

     if (nativeName == NULL) {

 	return NULL;

     }

     switch (mode & (O_RDONLY | O_WRONLY | O_RDWR)) {

 	case O_RDONLY:

 	    accessMode = GENERIC_READ;

 	    channelPermissions = TCL_READABLE;

 	    break;

 	case O_WRONLY:

 	    accessMode = GENERIC_WRITE;

 	    channelPermissions = TCL_WRITABLE;

 	    break;

 	case O_RDWR:

 	    accessMode = (GENERIC_READ | GENERIC_WRITE);

 	    channelPermissions = (TCL_READABLE | TCL_WRITABLE);

 	    break;

 	default:

 	    panic("TclpOpenFileChannel: invalid mode value");

 	    break;

     }

     /*

      * Map the creation flags to the NT create mode.

      */

     switch (mode & (O_CREAT | O_EXCL | O_TRUNC)) {

 	case (O_CREAT | O_EXCL):

 	case (O_CREAT | O_EXCL | O_TRUNC):

 	    createMode = CREATE_NEW;

 	    break;

 	case (O_CREAT | O_TRUNC):

 	    createMode = CREATE_ALWAYS;

 	    break;

 	case O_CREAT:

 	    createMode = OPEN_ALWAYS;

 	    break;

 	case O_TRUNC:

 	case (O_TRUNC | O_EXCL):

 	    createMode = TRUNCATE_EXISTING;

 	    break;

 	default:

 	    createMode = OPEN_EXISTING;

 	    break;

     }

     /*

      * If the file is being created, get the file attributes from the

      * permissions argument, else use the existing file attributes.

      */

     if (mode & O_CREAT) {

         if (permissions & S_IWRITE) {

             flags = FILE_ATTRIBUTE_NORMAL;

         } else {

             flags = FILE_ATTRIBUTE_READONLY;

         }

     } else {

 	flags = (*tclWinProcs->getFileAttributesProc)(nativeName);

         if (flags == 0xFFFFFFFF) {

 	    flags = 0;

 	}

     }

     /*

      * Set up the file sharing mode.  We want to allow simultaneous access.

      */

     shareMode = FILE_SHARE_READ | FILE_SHARE_WRITE;

     /*

      * Now we get to create the file.

      */

     handle = (*tclWinProcs->createFileProc)(nativeName, accessMode, 

 	    shareMode, NULL, createMode, flags, (HANDLE) NULL);

     if (handle == INVALID_HANDLE_VALUE) {

 	DWORD err;

 	err = GetLastError();

 	if ((err & 0xffffL) == ERROR_OPEN_FAILED) {

 	    err = (mode & O_CREAT) ? ERROR_FILE_EXISTS : ERROR_FILE_NOT_FOUND;

 	}

         TclWinConvertError(err);

 	if (interp != (Tcl_Interp *) NULL) {

             Tcl_AppendResult(interp, "couldn't open \"", 

 			     Tcl_GetString(pathPtr), "\": ",

 			     Tcl_PosixError(interp), (char *) NULL);

         }

         return NULL;

     }

     channel = NULL;

     switch ( FileGetType(handle) ) {

     case FILE_TYPE_SERIAL:

 	/*

 	 * Reopen channel for OVERLAPPED operation

 	 * Normally this shouldn't fail, because the channel exists

 	 */

 	handle = TclWinSerialReopen(handle, nativeName, accessMode);

 	if (handle == INVALID_HANDLE_VALUE) {

 	    TclWinConvertError(GetLastError());

 	    if (interp != (Tcl_Interp *) NULL) {

 		Tcl_AppendResult(interp, "couldn't reopen serial \"",

 			Tcl_GetString(pathPtr), "\": ",

 			Tcl_PosixError(interp), (char *) NULL);

 	    }

 	    return NULL;

 	}

 	channel = TclWinOpenSerialChannel(handle, channelName,

 	        channelPermissions);

 	break;

     case FILE_TYPE_CONSOLE:

 	channel = TclWinOpenConsoleChannel(handle, channelName,

 	        channelPermissions);

 	break;

     case FILE_TYPE_PIPE:

 	if (channelPermissions & TCL_READABLE) {

 	    readFile = TclWinMakeFile(handle);

 	}

 	if (channelPermissions & TCL_WRITABLE) {

 	    writeFile = TclWinMakeFile(handle);

 	}

 	channel = TclpCreateCommandChannel(readFile, writeFile, NULL, 0, NULL);

 	break;

     case FILE_TYPE_CHAR:

     case FILE_TYPE_DISK:

     case FILE_TYPE_UNKNOWN:

 	channel = TclWinOpenFileChannel(handle, channelName,

 					channelPermissions,

 					(mode & O_APPEND) ? FILE_APPEND : 0);

 	break;

     default:

 	/*

 	 * The handle is of an unknown type, probably /dev/nul equivalent

 	 * or possibly a closed handle.  

 	 */

 	channel = NULL;

 	Tcl_AppendResult(interp, "couldn't open \"", 

 			 Tcl_GetString(pathPtr), "\": ",

 			 "bad file type", (char *) NULL);

 	break;

     }

     return channel;

 }

 /*

  *----------------------------------------------------------------------

  *

  * Tcl_MakeFileChannel --

  *

  *	Creates a Tcl_Channel from an existing platform specific file

  *	handle.

  *

  * Results:

  *	The Tcl_Channel created around the preexisting file.

  *

  * Side effects:

  *	None.

  *

  *----------------------------------------------------------------------

  */

 Tcl_Channel

 Tcl_MakeFileChannel(rawHandle, mode)

     ClientData rawHandle;	/* OS level handle */

     int mode;			/* ORed combination of TCL_READABLE and

                                  * TCL_WRITABLE to indicate file mode. */

 {

 #ifdef HAVE_NO_SEH

     EXCEPTION_REGISTRATION registration;

 #endif

     char channelName[16 + TCL_INTEGER_SPACE];

     Tcl_Channel channel = NULL;

     HANDLE handle = (HANDLE) rawHandle;

     HANDLE dupedHandle;

     TclFile readFile = NULL;

     TclFile writeFile = NULL;

     BOOL result;

     if (mode == 0) {

 	return NULL;

     }

     switch (FileGetType(handle))

     {

     case FILE_TYPE_SERIAL:

 	channel = TclWinOpenSerialChannel(handle, channelName, mode);

 	break;

     case FILE_TYPE_CONSOLE:

 	channel = TclWinOpenConsoleChannel(handle, channelName, mode);

 	break;

     case FILE_TYPE_PIPE:

 	if (mode & TCL_READABLE)

 	{

 	    readFile = TclWinMakeFile(handle);

 	}

 	if (mode & TCL_WRITABLE)

 	{

 	    writeFile = TclWinMakeFile(handle);

 	}

 	channel = TclpCreateCommandChannel(readFile, writeFile, NULL, 0, NULL);

 	break;

     case FILE_TYPE_DISK:

     case FILE_TYPE_CHAR:

 	channel = TclWinOpenFileChannel(handle, channelName, mode, 0);

 	break;

     case FILE_TYPE_UNKNOWN:

     default:

 	/*

 	 * 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.

 	 */

 	result = 0;

 #ifndef HAVE_NO_SEH

 	__try {

 	    CloseHandle(dupedHandle);

 	    result = 1;

 	} __except (EXCEPTION_EXECUTE_HANDLER) {}

 #else

 	/*

 	 * Don't have SEH available, do things the hard way.

 	 * Note that this needs to be one block of asm, to avoid stack

 	 * imbalance; also, it is illegal for one asm block to contain 

 	 * a jump to another.

 	 */

 	__asm__ __volatile__ (

 	    /*

 	     * Pick up parameters before messing with the stack

 	     */

 	    "movl       %[dupedHandle], %%ebx"          "\n\t"

 	    /*

 	     * Construct an EXCEPTION_REGISTRATION to protect the

 	     * call to CloseHandle

 	     */

 	    "leal       %[registration], %%edx"         "\n\t"

 	    "movl       %%fs:0,         %%eax"          "\n\t"

 	    "movl       %%eax,          0x0(%%edx)"     "\n\t" /* link */

 	    "leal       1f,             %%eax"          "\n\t"

 	    "movl       %%eax,          0x4(%%edx)"     "\n\t" /* handler */

 	    "movl       %%ebp,          0x8(%%edx)"     "\n\t" /* ebp */

 	    "movl       %%esp,          0xc(%%edx)"     "\n\t" /* esp */

 	    "movl       $0,             0x10(%%edx)"    "\n\t" /* status */

 	    /* Link the EXCEPTION_REGISTRATION on the chain */

 	    "movl       %%edx,          %%fs:0"         "\n\t"

 	    /* Call CloseHandle( dupedHandle ) */

 	    "pushl      %%ebx"                          "\n\t"

 	    "call       _CloseHandle@4"                 "\n\t"

 	    /* 

 	     * Come here on normal exit.  Recover the EXCEPTION_REGISTRATION

 	     * and put a TRUE status return into it.

 	     */

 	    "movl       %%fs:0,         %%edx"          "\n\t"

 	    "movl	$1,		%%eax"		"\n\t"

 	    "movl       %%eax,          0x10(%%edx)"    "\n\t"

 	    "jmp        2f"                             "\n"

 	    /*

 	     * Come here on an exception.  Recover the EXCEPTION_REGISTRATION

 	     */

 	    "1:"                                        "\t"

 	    "movl       %%fs:0,         %%edx"          "\n\t"

 	    "movl       0x8(%%edx),     %%edx"          "\n\t"

 	    /* 

 	     * Come here however we exited.  Restore context from the

 	     * EXCEPTION_REGISTRATION in case the stack is unbalanced.

 	     */

 	    "2:"                                        "\t"

 	    "movl       0xc(%%edx),     %%esp"          "\n\t"

 	    "movl       0x8(%%edx),     %%ebp"          "\n\t"

 	    "movl       0x0(%%edx),     %%eax"          "\n\t"

 	    "movl       %%eax,          %%fs:0"         "\n\t"

 	    :

 	    /* No outputs */

 	    :

 	    [registration]  "m"     (registration),

 	    [dupedHandle]   "m"	    (dupedHandle)

 	    :

 	    "%eax", "%ebx", "%ecx", "%edx", "%esi", "%edi", "memory"

 	    );

 	result = registration.status;

 #endif

 	if (result == FALSE) {

 	    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;

 }

 /*

  *----------------------------------------------------------------------

  *

  * TclpGetDefaultStdChannel --

  *

  *	Constructs a channel for the specified standard OS handle.

  *

  * Results:

  *	Returns the specified default standard channel, or NULL.

  *

  * Side effects:

  *	May cause the creation of a standard channel and the underlying

  *	file.

  *

  *----------------------------------------------------------------------

  */

 Tcl_Channel

 TclpGetDefaultStdChannel(type)

     int type;			/* One of TCL_STDIN, TCL_STDOUT, TCL_STDERR. */

 {

     Tcl_Channel channel;

     HANDLE handle;

     int mode;

     char *bufMode;

     DWORD handleId;		/* Standard handle to retrieve. */

     switch (type) {

 	case TCL_STDIN:

 	    handleId = STD_INPUT_HANDLE;

 	    mode = TCL_READABLE;

 	    bufMode = "line";

 	    break;

 	case TCL_STDOUT:

 	    handleId = STD_OUTPUT_HANDLE;

 	    mode = TCL_WRITABLE;

 	    bufMode = "line";

 	    break;

 	case TCL_STDERR:

 	    handleId = STD_ERROR_HANDLE;

 	    mode = TCL_WRITABLE;

 	    bufMode = "none";

 	    break;

 	default:

 	    panic("TclGetDefaultStdChannel: Unexpected channel type");

 	    break;

     }

     handle = GetStdHandle(handleId);

     /*

      * Note that we need to check for 0 because Windows may return 0 if this

      * is not a console mode application, even though this is not a valid

      * handle.

      */

     if ((handle == INVALID_HANDLE_VALUE) || (handle == 0)) {

 	return (Tcl_Channel) NULL;

     }

     channel = Tcl_MakeFileChannel(handle, mode);

     if (channel == NULL) {

 	return (Tcl_Channel) NULL;

     }

     /*

      * Set up the normal channel options for stdio handles.

      */

     if ((Tcl_SetChannelOption((Tcl_Interp *) NULL, channel, "-translation",

             "auto") == TCL_ERROR)

 	    || (Tcl_SetChannelOption((Tcl_Interp *) NULL, channel, "-eofchar",

 		    "\032 {}") == TCL_ERROR)

 	    || (Tcl_SetChannelOption((Tcl_Interp *) NULL, channel,

 		    "-buffering", bufMode) == TCL_ERROR)) {

         Tcl_Close((Tcl_Interp *) NULL, channel);

         return (Tcl_Channel) NULL;

     }

     return channel;

 }

 /*

  *----------------------------------------------------------------------

  *

  * TclWinOpenFileChannel --

  *

  *	Constructs a File channel for the specified standard OS handle.

  *      This is a helper function to break up the construction of 

  *      channels into File, Console, or Serial.

  *

  * Results:

  *	Returns the new channel, or NULL.

  *

  * Side effects:

  *	May open the channel and may cause creation of a file on the

  *	file system.

  *

  *----------------------------------------------------------------------

  */

 Tcl_Channel

 TclWinOpenFileChannel(handle, channelName, permissions, appendMode)

     HANDLE handle;

     char *channelName;

     int permissions;

     int appendMode;

 {

     FileInfo *infoPtr;

     ThreadSpecificData *tsdPtr;

     tsdPtr = FileInit();

     /*

      * See if a channel with this handle already exists.

      */

     for (infoPtr = tsdPtr->firstFilePtr; infoPtr != NULL; 

 	 infoPtr = infoPtr->nextPtr) {

 	if (infoPtr->handle == (HANDLE) handle) {

 	    return (permissions == infoPtr->validMask) ? infoPtr->channel : NULL;

 	}

     }

     infoPtr = (FileInfo *) ckalloc((unsigned) sizeof(FileInfo));

     /* TIP #218. Removed the code inserting the new structure

      * into the global list. This is now handled in the thread

      * action callbacks, and only there.

      */

     infoPtr->nextPtr = NULL;

     infoPtr->validMask = permissions;

     infoPtr->watchMask = 0;

     infoPtr->flags = appendMode;

     infoPtr->handle = handle;

     infoPtr->dirty = 0;

     wsprintfA(channelName, "file%lx", (int) infoPtr);

     infoPtr->channel = Tcl_CreateChannel(&fileChannelType, channelName,

 	    (ClientData) infoPtr, permissions);

     /*

      * Files have default translation of AUTO and ^Z eof char, which

      * means that a ^Z will be accepted as EOF when reading.

      */

     Tcl_SetChannelOption(NULL, infoPtr->channel, "-translation", "auto");

     Tcl_SetChannelOption(NULL, infoPtr->channel, "-eofchar", "\032 {}");

     return infoPtr->channel;

 }

 /*

  *----------------------------------------------------------------------

  *

  * TclWinFlushDirtyChannels --

  *

  *	Flush all dirty channels to disk, so that requesting the

  *	size of any file returns the correct value.

  *

  * Results:

  *	None.

  *

  * Side effects:

  *	Information is actually written to disk now, rather than

  *	later.  Don't call this too often, or there will be a 

  *	performance hit (i.e. only call when we need to ask for

  *	the size of a file).

  *

  *----------------------------------------------------------------------

  */

 void

 TclWinFlushDirtyChannels ()

 {

     FileInfo *infoPtr;

     ThreadSpecificData *tsdPtr;

     tsdPtr = FileInit();

     /*

      * Flush all channels which are dirty, i.e. may have data pending

      * in the OS

      */

     for (infoPtr = tsdPtr->firstFilePtr;

 	 infoPtr != NULL; 

 	 infoPtr = infoPtr->nextPtr) {

 	if (infoPtr->dirty) {

 	    FlushFileBuffers(infoPtr->handle);

 	    infoPtr->dirty = 0;

 	}

     }

 }

 /*

  *----------------------------------------------------------------------

  *

  * FileThreadActionProc --

  *

  *	Insert or remove any thread local refs to this channel.

  *

  * Results:

  *	None.

  *

  * Side effects:

  *	Changes thread local list of valid channels.

  *

  *----------------------------------------------------------------------

  */

 static void

 FileThreadActionProc (instanceData, action)

      ClientData instanceData;

      int action;

 {

     ThreadSpecificData *tsdPtr = TCL_TSD_INIT(&dataKey);

     FileInfo *infoPtr = (FileInfo *) instanceData;

     if (action == TCL_CHANNEL_THREAD_INSERT) {

         infoPtr->nextPtr = tsdPtr->firstFilePtr;

 	tsdPtr->firstFilePtr = infoPtr;

     } else {

         FileInfo **nextPtrPtr;

 	int removed = 0;

 	for (nextPtrPtr = &(tsdPtr->firstFilePtr); (*nextPtrPtr) != NULL;

 	     nextPtrPtr = &((*nextPtrPtr)->nextPtr)) {

 	    if ((*nextPtrPtr) == infoPtr) {

 	        (*nextPtrPtr) = infoPtr->nextPtr;

 		removed = 1;

 		break;

 	    }

 	}

 	/*

 	 * This could happen if the channel was created in one thread

 	 * and then moved to another without updating the thread

 	 * local data in each thread.

 	 */

 	if (!removed) {

 	    panic("file info ptr not on thread channel list");

 	}

     }

 }

 /*

  *----------------------------------------------------------------------

  *

  * FileGetType --

  *

  *	Given a file handle, return its type

  *

  * Results:

  *	None.

  *

  * Side effects:

  *	None.

  *

  *----------------------------------------------------------------------

  */

 DWORD

 FileGetType(handle)

     HANDLE handle; /* Opened file handle */

 { 

     DWORD type;

     DWORD consoleParams;

     DCB dcb;

     type = GetFileType(handle);

     /*

      * If the file is a character device, we need to try to figure out

      * whether it is a serial port, a console, or something else.  We

      * test for the console case first because this is more common.

      */

     if (type == FILE_TYPE_CHAR || (type == FILE_TYPE_UNKNOWN && !GetLastError())) {

 	    if (GetConsoleMode(handle, &consoleParams)) {

 	      type = FILE_TYPE_CONSOLE;

       } else {

 	      dcb.DCBlength = sizeof( DCB ) ;

 	      if (GetCommState(handle, &dcb)) {

 		      type = FILE_TYPE_SERIAL;

         }

       }

     }

     return type;

 }