tclunixpipe.c

linux系统下的音频通信

            
            fcntl(targetFd, F_SETFD, 0);
	} else {
	    int result;

	    /*
	     * Since we aren't dup'ing the file, we need to explicitly clear
	     * the close-on-exec flag.
	     */

	    result = fcntl(fd, F_SETFD, 0);
	}
    } else {
	close(targetFd);
    }
    return 1;
}

/*
 *----------------------------------------------------------------------
 *
 * TclpCreateCommandChannel --
 *
 *	This function is called by the generic IO level to perform
 *	the platform specific channel initialization for a command
 *	channel.
 *
 * Results:
 *	Returns a new channel or NULL on failure.
 *
 * Side effects:
 *	Allocates a new channel.
 *
 *----------------------------------------------------------------------
 */

Tcl_Channel
TclpCreateCommandChannel(readFile, writeFile, errorFile, numPids, pidPtr)
    TclFile readFile;		/* If non-null, gives the file for reading. */
    TclFile writeFile;		/* If non-null, gives the file for writing. */
    TclFile errorFile;		/* If non-null, gives the file where errors
				 * can be read. */
    int numPids;		/* The number of pids in the pid array. */
    Tcl_Pid *pidPtr;		/* An array of process identifiers.
                                 * Allocated by the caller, freed when
                                 * the channel is closed or the processes
                                 * are detached (in a background exec). */
{
    char channelName[20];
    int channelId;
    PipeState *statePtr = (PipeState *) ckalloc((unsigned) sizeof(PipeState));
    int mode;

    statePtr->inFile = readFile;
    statePtr->outFile = writeFile;
    statePtr->errorFile = errorFile;
    statePtr->numPids = numPids;
    statePtr->pidPtr = pidPtr;
    statePtr->isNonBlocking = 0;

    mode = 0;
    if (readFile) {
        mode |= TCL_READABLE;
    }
    if (writeFile) {
        mode |= TCL_WRITABLE;
    }
    
    /*
     * Use one of the fds associated with the channel as the
     * channel id.
     */

    if (readFile) {
	channelId = GetFd(readFile);
    } else if (writeFile) {
	channelId = GetFd(writeFile);
    } else if (errorFile) {
	channelId = GetFd(errorFile);
    } else {
	channelId = 0;
    }

    /*
     * For backward compatibility with previous versions of Tcl, we
     * use "file%d" as the base name for pipes even though it would
     * be more natural to use "pipe%d".
     */

    sprintf(channelName, "file%d", channelId);
    statePtr->channel = Tcl_CreateChannel(&pipeChannelType, channelName,
            (ClientData) statePtr, mode);
    return statePtr->channel;
}

/*
 *----------------------------------------------------------------------
 *
 * TclGetAndDetachPids --
 *
 *	This procedure is invoked in the generic implementation of a
 *	background "exec" (An exec when invoked with a terminating "&")
 *	to store a list of the PIDs for processes in a command pipeline
 *	in interp->result and to detach the processes.
 *
 * Results:
 *	None.
 *
 * Side effects:
 *	Modifies interp->result. Detaches processes.
 *
 *----------------------------------------------------------------------
 */

void
TclGetAndDetachPids(interp, chan)
    Tcl_Interp *interp;
    Tcl_Channel chan;
{
    PipeState *pipePtr;
    Tcl_ChannelType *chanTypePtr;
    int i;
    char buf[20];

    /*
     * Punt if the channel is not a command channel.
     */

    chanTypePtr = Tcl_GetChannelType(chan);
    if (chanTypePtr != &pipeChannelType) {
        return;
    }

    pipePtr = (PipeState *) Tcl_GetChannelInstanceData(chan);
    for (i = 0; i < pipePtr->numPids; i++) {
        sprintf(buf, "%ld", TclpGetPid(pipePtr->pidPtr[i]));
        Tcl_AppendElement(interp, buf);
        Tcl_DetachPids(1, &(pipePtr->pidPtr[i]));
    }
    if (pipePtr->numPids > 0) {
        ckfree((char *) pipePtr->pidPtr);
        pipePtr->numPids = 0;
    }
}

/*
 *----------------------------------------------------------------------
 *
 * PipeBlockModeProc --
 *
 *	Helper procedure to set blocking and nonblocking modes on a
 *	pipe based channel. Invoked by generic IO level code.
 *
 * Results:
 *	0 if successful, errno when failed.
 *
 * Side effects:
 *	Sets the device into blocking or non-blocking mode.
 *
 *----------------------------------------------------------------------
 */

	/* ARGSUSED */
static int
PipeBlockModeProc(instanceData, mode)
    ClientData instanceData;		/* Pipe state. */
    int mode;				/* The mode to set. Can be one of
                                         * TCL_MODE_BLOCKING or
                                         * TCL_MODE_NONBLOCKING. */
{
    PipeState *psPtr = (PipeState *) instanceData;
    int curStatus;
    int fd;

#ifndef	USE_FIONBIO    
    if (psPtr->inFile) {
        fd = GetFd(psPtr->inFile);
        curStatus = fcntl(fd, F_GETFL);
        if (mode == TCL_MODE_BLOCKING) {
            curStatus &= (~(O_NONBLOCK));
        } else {
            curStatus |= O_NONBLOCK;
        }
        if (fcntl(fd, F_SETFL, curStatus) < 0) {
            return errno;
        }
        curStatus = fcntl(fd, F_GETFL);
    }
    if (psPtr->outFile) {
        fd = GetFd(psPtr->outFile);
        curStatus = fcntl(fd, F_GETFL);
        if (mode == TCL_MODE_BLOCKING) {
            curStatus &= (~(O_NONBLOCK));
        } else {
            curStatus |= O_NONBLOCK;
        }
        if (fcntl(fd, F_SETFL, curStatus) < 0) {
            return errno;
        }
    }
#endif	/* !FIONBIO */

#ifdef	USE_FIONBIO
    if (psPtr->inFile) {
        fd = GetFd(psPtr->inFile);
        if (mode == TCL_MODE_BLOCKING) {
            curStatus = 0;
        } else {
            curStatus = 1;
        }
        if (ioctl(fd, (int) FIONBIO, &curStatus) < 0) {
            return errno;
        }
    }
    if (psPtr->outFile != NULL) {
        fd = GetFd(psPtr->outFile);
        if (mode == TCL_MODE_BLOCKING) {
            curStatus = 0;
        } else {
            curStatus = 1;
        }
        if (ioctl(fd, (int) FIONBIO,  &curStatus) < 0) {
            return errno;
        }
    }
#endif	/* USE_FIONBIO */
    
    return 0;
}

/*
 *----------------------------------------------------------------------
 *
 * PipeCloseProc --
 *
 *	This procedure is invoked by the generic IO level to perform
 *	channel-type-specific cleanup when a command pipeline channel
 *	is closed.
 *
 * Results:
 *	0 on success, errno otherwise.
 *
 * Side effects:
 *	Closes the command pipeline channel.
 *
 *----------------------------------------------------------------------
 */

	/* ARGSUSED */
static int
PipeCloseProc(instanceData, interp)
    ClientData instanceData;	/* The pipe to close. */
    Tcl_Interp *interp;		/* For error reporting. */
{
    PipeState *pipePtr;
    Tcl_Channel errChan;
    int errorCode, result;

    errorCode = 0;
    result = 0;
    pipePtr = (PipeState *) instanceData;
    if (pipePtr->inFile) {
	if (TclpCloseFile(pipePtr->inFile) < 0) {
	    errorCode = errno;
	}
    }
    if (pipePtr->outFile) {
	if ((TclpCloseFile(pipePtr->outFile) < 0) && (errorCode == 0)) {
	    errorCode = errno;
	}
    }

    if (pipePtr->isNonBlocking || TclInExit()) {
    
	/*
         * If the channel is non-blocking or Tcl is being cleaned up, just
         * detach the children PIDs, reap them (important if we are in a
         * dynamic load module), and discard the errorFile.
         */
        
        Tcl_DetachPids(pipePtr->numPids, pipePtr->pidPtr);
        Tcl_ReapDetachedProcs();

        if (pipePtr->errorFile) {
	    TclpCloseFile(pipePtr->errorFile);
        }
    } else {
        
	/*
         * Wrap the error file into a channel and give it to the cleanup
         * routine.
         */

        if (pipePtr->errorFile) {
	    errChan = Tcl_MakeFileChannel(
		(ClientData) GetFd(pipePtr->errorFile), TCL_READABLE);
        } else {
            errChan = NULL;
        }
        result = TclCleanupChildren(interp, pipePtr->numPids, pipePtr->pidPtr,
                errChan);
    }

    if (pipePtr->numPids != 0) {
        ckfree((char *) pipePtr->pidPtr);
    }
    ckfree((char *) pipePtr);
    if (errorCode == 0) {
        return result;
    }
    return errorCode;
}

/*
 *----------------------------------------------------------------------
 *
 * PipeInputProc --
 *
 *	This procedure is invoked from the generic IO level to read
 *	input from a command pipeline based channel.
 *
 * Results:
 *	The number of bytes read is returned or -1 on error. An output
 *	argument contains a POSIX error code if an error occurs, or zero.
 *
 * Side effects:
 *	Reads input from the input device of the channel.
 *
 *----------------------------------------------------------------------
 */

static int
PipeInputProc(instanceData, buf, toRead, errorCodePtr)
    ClientData instanceData;		/* Pipe state. */
    char *buf;				/* Where to store data read. */
    int toRead;				/* How much space is available
                                         * in the buffer? */
    int *errorCodePtr;			/* Where to store error code. */
{
    PipeState *psPtr = (PipeState *) instanceData;
    int bytesRead;			/* How many bytes were actually
                                         * read from the input device? */

    *errorCodePtr = 0;
    
    /*
     * Assume there is always enough input available. This will block
     * appropriately, and read will unblock as soon as a short read is
     * possible, if the channel is in blocking mode. If the channel is
     * nonblocking, the read will never block.
     */

    bytesRead = read(GetFd(psPtr->inFile), buf, (size_t) toRead);
    if (bytesRead > -1) {
        return bytesRead;
    }
    *errorCodePtr = errno;
    return -1;
}

/*
 *----------------------------------------------------------------------
 *
 * PipeOutputProc--
 *
 *	This procedure is invoked from the generic IO level to write
 *	output to a command pipeline based channel.
 *
 * Results:
 *	The number of bytes written is returned or -1 on error. An
 *	output argument	contains a POSIX error code if an error occurred,
 *	or zero.
 *
 * Side effects:
 *	Writes output on the output device of the channel.
 *
 *----------------------------------------------------------------------
 */

static int
PipeOutputProc(instanceData, buf, toWrite, errorCodePtr)
    ClientData instanceData;		/* Pipe state. */
    char *buf;				/* The data buffer. */
    int toWrite;			/* How many bytes to write? */
    int *errorCodePtr;			/* Where to store error code. */
{
    PipeState *psPtr = (PipeState *) instanceData;
    int written;

    *errorCodePtr = 0;
    written = write(GetFd(psPtr->outFile), buf, (size_t) toWrite);
    if (written > -1) {
        return written;
    }
    *errorCodePtr = errno;
    return -1;
}

/*
 *----------------------------------------------------------------------
 *
 * PipeWatchProc --
 *
 *	Initialize the notifier to watch the fds from this channel.
 *
 * Results:
 *	None.
 *
 * Side effects:
 *	Sets up the notifier so that a future event on the channel will
 *	be seen by Tcl.
 *
 *----------------------------------------------------------------------
 */

static void
PipeWatchProc(instanceData, mask)
    ClientData instanceData;		/* The pipe state. */
    int mask;				/* Events of interest; an OR-ed
                                         * combination of TCL_READABLE,
                                         * TCL_WRITABEL and TCL_EXCEPTION. */
{
    PipeState *psPtr = (PipeState *) instanceData;
    int newmask;

    if (psPtr->inFile) {
	newmask = mask & (TCL_READABLE | TCL_EXCEPTION);
	if (newmask) {
	    Tcl_CreateFileHandler(GetFd(psPtr->inFile), mask,
		    (Tcl_FileProc *) Tcl_NotifyChannel,
		    (ClientData) psPtr->channel);
	} else {
	    Tcl_DeleteFileHandler(GetFd(psPtr->inFile));
	}
    }
    if (psPtr->outFile) {
	newmask = mask & (TCL_WRITABLE | TCL_EXCEPTION);
	if (newmask) {
	    Tcl_CreateFileHandler(GetFd(psPtr->outFile), mask,
		    (Tcl_FileProc *) Tcl_NotifyChannel,
		    (ClientData) psPtr->channel);
	} else {
	    Tcl_DeleteFileHandler(GetFd(psPtr->outFile));
	}
    }
}

/*
 *----------------------------------------------------------------------
 *
 * PipeGetHandleProc --
 *
 *	Called from Tcl_GetChannelHandle to retrieve OS handles from
 *	inside a command pipeline 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
PipeGetHandleProc(instanceData, direction, handlePtr)
    ClientData instanceData;	/* The pipe state. */
    int direction;		/* TCL_READABLE or TCL_WRITABLE */
    ClientData *handlePtr;	/* Where to store the handle.  */
{
    PipeState *psPtr = (PipeState *) instanceData;

    if (direction == TCL_READABLE && psPtr->inFile) {
	*handlePtr = (ClientData) GetFd(psPtr->inFile);
	return TCL_OK;
    }
    if (direction == TCL_WRITABLE && psPtr->outFile) {
	*handlePtr = (ClientData) GetFd(psPtr->outFile);
	return TCL_OK;
    }
    return TCL_ERROR;
}

/*
 *----------------------------------------------------------------------
 *
 * Tcl_WaitPid --
 *
 *	Implements the waitpid system call on Unix systems.
 *
 * Results:
 *	Result of calling waitpid.
 *
 * Side effects:
 *	Waits for a process to terminate.
 *
 *----------------------------------------------------------------------
 */

Tcl_Pid
Tcl_WaitPid(pid, statPtr, options)
    Tcl_Pid pid;
    int *statPtr;
    int options;
{
    int result;
    pid_t real_pid;

    real_pid = (pid_t) pid;
    while (1) {
	result = (int) waitpid(real_pid, statPtr, options);
	if ((result != -1) || (errno != EINTR)) {
	    return (Tcl_Pid) result;
	}
    }
}

/*
 *----------------------------------------------------------------------
 *
 * Tcl_PidObjCmd --
 *
 *	This procedure is invoked to process the "pid" Tcl command.
 *	See the user documentation for details on what it does.
 *
 * Results:
 *	A standard Tcl result.
 *
 * Side effects:
 *	See the user documentation.
 *
 *----------------------------------------------------------------------
 */

	/* ARGSUSED */
int
Tcl_PidObjCmd(dummy, interp, objc, objv)
    ClientData dummy;		/* Not used. */
    Tcl_Interp *interp;		/* Current interpreter. */
    int objc;			/* Number of arguments. */
    Tcl_Obj *CONST *objv;	/* Argument strings. */
{
    Tcl_Channel chan;
    Tcl_ChannelType *chanTypePtr;
    PipeState *pipePtr;
    int i;
    Tcl_Obj *resultPtr, *longObjPtr;

    if (objc > 2) {
	Tcl_WrongNumArgs(interp, 1, objv, "?channelId?");
	return TCL_ERROR;
    }
    if (objc == 1) {
	Tcl_SetLongObj(Tcl_GetObjResult(interp), (long) getpid());
    } else {
        chan = Tcl_GetChannel(interp, Tcl_GetStringFromObj(objv[1], NULL),
		NULL);
        if (chan == (Tcl_Channel) NULL) {
	    return TCL_ERROR;
	}
	chanTypePtr = Tcl_GetChannelType(chan);
	if (chanTypePtr != &pipeChannelType) {
	    return TCL_OK;
	}
        pipePtr = (PipeState *) Tcl_GetChannelInstanceData(chan);
	resultPtr = Tcl_GetObjResult(interp);
        for (i = 0; i < pipePtr->numPids; i++) {
	    longObjPtr = Tcl_NewLongObj((long) TclpGetPid(pipePtr->pidPtr[i]));
	    Tcl_ListObjAppendElement(NULL, resultPtr, longObjPtr);
	}
    }
    return TCL_OK;
}