tclwinchan.c

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                                 * TCL_WRITABLE to indicate file mode. */
{
    char channelName[16 + TCL_INTEGER_SPACE];
    Tcl_Channel channel = NULL;
    HANDLE handle = (HANDLE) rawHandle;
    HANDLE dupedHandle;
    DCB dcb;
    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);

    /*
     * 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) {
	if (GetConsoleMode(handle, &consoleParams)) {
	    type = FILE_TYPE_CONSOLE;
	} else {
	    dcb.DCBlength = sizeof( DCB ) ;
	    if (GetCommState(handle, &dcb)) {
		type = FILE_TYPE_SERIAL;
	    }
	}
    }

    switch (type)
    {
    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.
	 */

#ifdef HAVE_NO_SEH
# ifdef TCL_MEM_DEBUG
        __asm__ __volatile__ (
            "movl %%esp,  %0" "\n\t"
            "movl %%ebp,  %1" "\n\t"
            "movl %%fs:0, %2" "\n\t"
            : "=m"(INITIAL_ESP),
              "=m"(INITIAL_EBP),
              "=r"(INITIAL_HANDLER) );
# endif /* TCL_MEM_DEBUG */

        result = 0;

        __asm__ __volatile__ (
            "pushl %ebp" "\n\t"
            "pushl $__except_makefilechannel_handler" "\n\t"
            "pushl %fs:0" "\n\t"
            "movl  %esp, %fs:0");
#else
	__try {
#endif /* HAVE_NO_SEH */
	    CloseHandle(dupedHandle);
#ifdef HAVE_NO_SEH
        __asm__ __volatile__ (
            "jmp  makefilechannel_pop" "\n"
        "makefilechannel_reentry:" "\n\t"
            "movl %%fs:0, %%eax" "\n\t"
            "movl 0x8(%%eax), %%esp" "\n\t"
            "movl 0x8(%%esp), %%ebp" "\n"
            "movl $1, %0" "\n"
        "makefilechannel_pop:" "\n\t"
            "movl (%%esp), %%eax" "\n\t"
            "movl %%eax, %%fs:0" "\n\t"
            "add  $12, %%esp" "\n\t"
            : "=m"(result)
            :
            : "%eax");

# ifdef TCL_MEM_DEBUG
    __asm__ __volatile__ (
            "movl  %%esp,  %0" "\n\t"
            "movl  %%ebp,  %1" "\n\t"
            "movl  %%fs:0, %2" "\n\t"
            : "=m"(RESTORED_ESP),
              "=m"(RESTORED_EBP),
              "=r"(RESTORED_HANDLER) );

    if (INITIAL_ESP != RESTORED_ESP)
        panic("ESP restored incorrectly");
    if (INITIAL_EBP != RESTORED_EBP)
        panic("EBP restored incorrectly");
    if (INITIAL_HANDLER != RESTORED_HANDLER)
        panic("HANDLER restored incorrectly");
# endif /* TCL_MEM_DEBUG */

        if (result)
            return NULL;
#else
	}
	__except (EXCEPTION_EXECUTE_HANDLER) {
	    /*
	     * Definately an invalid handle.  So, therefore, the original
	     * is invalid also.
	     */

	    return NULL;
	}
#endif /* HAVE_NO_SEH */

	/* 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;
}
#ifdef HAVE_NO_SEH
static
__attribute__ ((cdecl))
EXCEPTION_DISPOSITION
_except_makefilechannel_handler(
    struct _EXCEPTION_RECORD *ExceptionRecord,
    void *EstablisherFrame,
    struct _CONTEXT *ContextRecord,
    void *DispatcherContext)
{
    __asm__ __volatile__ (
            "jmp makefilechannel_reentry");
    /* Nuke compiler warning about unused static function */
    _except_makefilechannel_handler(NULL, NULL, NULL, NULL);
    return 0; /* Function does not return */
}
#endif

/*
 *----------------------------------------------------------------------
 *
 * 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));
    infoPtr->nextPtr = tsdPtr->firstFilePtr;
    tsdPtr->firstFilePtr = infoPtr;
    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;
	}
    }
}

/*
 *----------------------------------------------------------------------
 *
 * TclpCutFileChannel --
 *
 *	Remove any thread local refs to this channel. See
 *	Tcl_CutChannel for more info.
 *
 * Results:
 *	None.
 *
 * Side effects:
 *	Changes thread local list of valid channels.
 *
 *----------------------------------------------------------------------
 */

void
TclpCutFileChannel(chan)
    Tcl_Channel chan;			/* The channel being removed. Must
                                         * not be referenced in any
                                         * interpreter. */
{
    ThreadSpecificData *tsdPtr = TCL_TSD_INIT(&dataKey);
    Channel *chanPtr = (Channel *) chan;
    FileInfo *infoPtr;
    FileInfo **nextPtrPtr;
    int removed = 0;

    if (chanPtr->typePtr != &fileChannelType)
        return;

    infoPtr = (FileInfo *) chanPtr->instanceData;

    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");

}

/*
 *----------------------------------------------------------------------
 *
 * TclpSpliceFileChannel --
 *
 *	Insert thread local ref for this channel.
 *	Tcl_SpliceChannel for more info.
 *
 * Results:
 *	None.
 *
 * Side effects:
 *	Changes thread local list of valid channels.
 *
 *----------------------------------------------------------------------
 */

void
TclpSpliceFileChannel(chan)
    Tcl_Channel chan;			/* The channel being removed. Must
                                         * not be referenced in any
                                         * interpreter. */
{
    ThreadSpecificData *tsdPtr = TCL_TSD_INIT(&dataKey);
    Channel *chanPtr = (Channel *) chan;
    FileInfo *infoPtr;

    if (chanPtr->typePtr != &fileChannelType)
        return;

    infoPtr = (FileInfo *) chanPtr->instanceData;

    infoPtr->nextPtr = tsdPtr->firstFilePtr;
    tsdPtr->firstFilePtr = infoPtr;
}