tclpipe.c

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                    Tcl_AppendResult(interp,
                            "child wait status didn't make sense\n",
                            (char *) NULL);
                }
	    }
	}
    }

    /*
     * Read the standard error file.  If there's anything there,
     * then return an error and add the file's contents to the result
     * string.
     */

    anyErrorInfo = 0;
    if (errorChan != NULL) {

	/*
	 * Make sure we start at the beginning of the file.
	 */

        if (interp != NULL) {
	    int count;
	    Tcl_Obj *objPtr;
	    
	    Tcl_Seek(errorChan, (Tcl_WideInt)0, SEEK_SET);
	    objPtr = Tcl_NewObj();
	    count = Tcl_ReadChars(errorChan, objPtr, -1, 0);
	    if (count < 0) {
		result = TCL_ERROR;
		Tcl_DecrRefCount(objPtr);
		Tcl_ResetResult(interp);
		Tcl_AppendResult(interp, "error reading stderr output file: ",
			Tcl_PosixError(interp), NULL);
	    } else if (count > 0) {
		anyErrorInfo = 1;
		Tcl_SetObjResult(interp, objPtr);
		result = TCL_ERROR;
	    } else {
		Tcl_DecrRefCount(objPtr);
	    }
	}
	Tcl_Close(NULL, errorChan);
    }

    /*
     * If a child exited abnormally but didn't output any error information
     * at all, generate an error message here.
     */

    if ((abnormalExit != 0) && (anyErrorInfo == 0) && (interp != NULL)) {
	Tcl_AppendResult(interp, "child process exited abnormally",
		(char *) NULL);
    }
    return result;
}

/*
 *----------------------------------------------------------------------
 *
 * TclCreatePipeline --
 *
 *	Given an argc/argv array, instantiate a pipeline of processes
 *	as described by the argv.
 *
 *	This procedure is unofficially exported for use by BLT.
 *
 * Results:
 *	The return value is a count of the number of new processes
 *	created, or -1 if an error occurred while creating the pipeline.
 *	*pidArrayPtr is filled in with the address of a dynamically
 *	allocated array giving the ids of all of the processes.  It
 *	is up to the caller to free this array when it isn't needed
 *	anymore.  If inPipePtr is non-NULL, *inPipePtr is filled in
 *	with the file id for the input pipe for the pipeline (if any):
 *	the caller must eventually close this file.  If outPipePtr
 *	isn't NULL, then *outPipePtr is filled in with the file id
 *	for the output pipe from the pipeline:  the caller must close
 *	this file.  If errFilePtr isn't NULL, then *errFilePtr is filled
 *	with a file id that may be used to read error output after the
 *	pipeline completes.
 *
 * Side effects:
 *	Processes and pipes are created.
 *
 *----------------------------------------------------------------------
 */

int
TclCreatePipeline(interp, argc, argv, pidArrayPtr, inPipePtr,
	outPipePtr, errFilePtr)
    Tcl_Interp *interp;		/* Interpreter to use for error reporting. */
    int argc;			/* Number of entries in argv. */
    CONST char **argv;		/* Array of strings describing commands in
				 * pipeline plus I/O redirection with <,
				 * <<,  >, etc.  Argv[argc] must be NULL. */
    Tcl_Pid **pidArrayPtr;	/* Word at *pidArrayPtr gets filled in with
				 * address of array of pids for processes
				 * in pipeline (first pid is first process
				 * in pipeline). */
    TclFile *inPipePtr;		/* If non-NULL, input to the pipeline comes
				 * from a pipe (unless overridden by
				 * redirection in the command).  The file
				 * id with which to write to this pipe is
				 * stored at *inPipePtr.  NULL means command
				 * specified its own input source. */
    TclFile *outPipePtr;	/* If non-NULL, output to the pipeline goes
				 * to a pipe, unless overriden by redirection
				 * in the command.  The file id with which to
				 * read frome this pipe is stored at
				 * *outPipePtr.  NULL means command specified
				 * its own output sink. */
    TclFile *errFilePtr;	/* If non-NULL, all stderr output from the
				 * pipeline will go to a temporary file
				 * created here, and a descriptor to read
				 * the file will be left at *errFilePtr.
				 * The file will be removed already, so
				 * closing this descriptor will be the end
				 * of the file.  If this is NULL, then
				 * all stderr output goes to our stderr.
				 * If the pipeline specifies redirection
				 * then the file will still be created
				 * but it will never get any data. */
{
    Tcl_Pid *pidPtr = NULL;	/* Points to malloc-ed array holding all
				 * the pids of child processes. */
    int numPids;		/* Actual number of processes that exist
				 * at *pidPtr right now. */
    int cmdCount;		/* Count of number of distinct commands
				 * found in argc/argv. */
    CONST char *inputLiteral = NULL;	/* If non-null, then this points to a
				 * string containing input data (specified
				 * via <<) to be piped to the first process
				 * in the pipeline. */
    TclFile inputFile = NULL;	/* If != NULL, gives file to use as input for
				 * first process in pipeline (specified via <
				 * or <@). */
    int inputClose = 0;		/* If non-zero, then inputFile should be 
    				 * closed when cleaning up. */
    int inputRelease = 0;
    TclFile outputFile = NULL;	/* Writable file for output from last command
				 * in pipeline (could be file or pipe).  NULL
				 * means use stdout. */
    int outputClose = 0;	/* If non-zero, then outputFile should be 
    				 * closed when cleaning up. */
    int outputRelease = 0;
    TclFile errorFile = NULL;	/* Writable file for error output from all
				 * commands in pipeline.  NULL means use
				 * stderr. */
    int errorClose = 0;		/* If non-zero, then errorFile should be 
    				 * closed when cleaning up. */
    int errorRelease = 0;
    CONST char *p;
    int skip, lastBar, lastArg, i, j, atOK, flags, errorToOutput;
    Tcl_DString execBuffer;
    TclFile pipeIn;
    TclFile curInFile, curOutFile, curErrFile;
    Tcl_Channel channel;

    if (inPipePtr != NULL) {
	*inPipePtr = NULL;
    }
    if (outPipePtr != NULL) {
	*outPipePtr = NULL;
    }
    if (errFilePtr != NULL) {
	*errFilePtr = NULL;
    }

    Tcl_DStringInit(&execBuffer);
    
    pipeIn = NULL;
    curInFile = NULL;
    curOutFile = NULL;
    numPids = 0;

    /*
     * First, scan through all the arguments to figure out the structure
     * of the pipeline.  Process all of the input and output redirection
     * arguments and remove them from the argument list in the pipeline.
     * Count the number of distinct processes (it's the number of "|"
     * arguments plus one) but don't remove the "|" arguments because 
     * they'll be used in the second pass to seperate the individual 
     * child processes.  Cannot start the child processes in this pass 
     * because the redirection symbols may appear anywhere in the 
     * command line -- e.g., the '<' that specifies the input to the 
     * entire pipe may appear at the very end of the argument list.
     */

    lastBar = -1;
    cmdCount = 1;
    for (i = 0; i < argc; i++) {
        skip = 0;
	p = argv[i];
	switch (*p++) {
	case '|':
	    if (*p == '&') {
		p++;
	    }
	    if (*p == '\0') {
		if ((i == (lastBar + 1)) || (i == (argc - 1))) {
		    Tcl_SetResult(interp,
			    "illegal use of | or |& in command",
			    TCL_STATIC);
		    goto error;
		}
	    }
	    lastBar = i;
	    cmdCount++;
	    break;

	case '<':
	    if (inputClose != 0) {
		inputClose = 0;
		TclpCloseFile(inputFile);
	    }
	    if (inputRelease != 0) {
		inputRelease = 0;
		TclpReleaseFile(inputFile);
	    }
	    if (*p == '<') {
		inputFile = NULL;
		inputLiteral = p + 1;
		skip = 1;
		if (*inputLiteral == '\0') {
		    inputLiteral = argv[i + 1];
		    if (inputLiteral == NULL) {
			Tcl_AppendResult(interp, "can't specify \"", argv[i],
				"\" as last word in command", (char *) NULL);
			goto error;
		    }
		    skip = 2;
		}
	    } else {
		inputLiteral = NULL;
		inputFile = FileForRedirect(interp, p, 1, argv[i], 
			argv[i + 1], O_RDONLY, &skip, &inputClose, &inputRelease);
		if (inputFile == NULL) {
		    goto error;
		}
	    }
	    break;

	case '>':
	    atOK = 1;
	    flags = O_WRONLY | O_CREAT | O_TRUNC;
	    errorToOutput = 0;
	    if (*p == '>') {
		p++;
		atOK = 0;
		flags = O_WRONLY | O_CREAT;
	    }
	    if (*p == '&') {
		if (errorClose != 0) {
		    errorClose = 0;
		    TclpCloseFile(errorFile);
		}
		errorToOutput = 1;
		p++;
	    }

	    /*
	     * Close the old output file, but only if the error file is
	     * not also using it.
	     */

	    if (outputClose != 0) {
		outputClose = 0;
		if (errorFile == outputFile) {
		    errorClose = 1;
		} else {
		    TclpCloseFile(outputFile);
		}
	    }
	    if (outputRelease != 0) {
		outputRelease = 0;
		if (errorFile == outputFile) {
		    errorRelease = 1;
		} else {
		    TclpReleaseFile(outputFile);
		}
	    }
	    outputFile = FileForRedirect(interp, p, atOK, argv[i], 
		    argv[i + 1], flags, &skip, &outputClose, &outputRelease);
	    if (outputFile == NULL) {
		goto error;
	    }
	    if (errorToOutput) {
		if (errorClose != 0) {
		    errorClose = 0;
		    TclpCloseFile(errorFile);
		}
		if (errorRelease != 0) {
		    errorRelease = 0;
		    TclpReleaseFile(errorFile);
		}
		errorFile = outputFile;
	    }
	    break;

	case '2':
	    if (*p != '>') {
		break;
	    }
	    p++;
	    atOK = 1;
	    flags = O_WRONLY | O_CREAT | O_TRUNC;
	    if (*p == '>') {
		p++;
		atOK = 0;
		flags = O_WRONLY | O_CREAT;
	    }
	    if (errorClose != 0) {
		errorClose = 0;
		TclpCloseFile(errorFile);
	    }
	    if (errorRelease != 0) {
		errorRelease = 0;
		TclpReleaseFile(errorFile);
	    }
	    errorFile = FileForRedirect(interp, p, atOK, argv[i], 
		    argv[i + 1], flags, &skip, &errorClose, &errorRelease);
	    if (errorFile == NULL) {
		goto error;
	    }
	    break;
	}

	if (skip != 0) {
	    for (j = i + skip; j < argc; j++) {
		argv[j - skip] = argv[j];
	    }
	    argc -= skip;
	    i -= 1;
	}
    }

    if (inputFile == NULL) {
	if (inputLiteral != NULL) {
	    /*
	     * The input for the first process is immediate data coming from
	     * Tcl.  Create a temporary file for it and put the data into the
	     * file.
	     */
	    inputFile = TclpCreateTempFile(inputLiteral);
	    if (inputFile == NULL) {
		Tcl_AppendResult(interp,
			"couldn't create input file for command: ",
			Tcl_PosixError(interp), (char *) NULL);
		goto error;
	    }
	    inputClose = 1;
	} else if (inPipePtr != NULL) {
	    /*
	     * The input for the first process in the pipeline is to
	     * come from a pipe that can be written from by the caller.
	     */