tclunixpipe.c

tcl是工具命令语言

/* 
 * tclUnixPipe.c --
 *
 *	This file implements the UNIX-specific exec pipeline functions,
 *	the "pipe" channel driver, and the "pid" Tcl command.
 *
 * Copyright (c) 1991-1994 The Regents of the University of California.
 * Copyright (c) 1994-1997 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: tclUnixPipe.c,v 1.23 2003/02/21 14:15:58 das Exp $
 */

#include "tclInt.h"
#include "tclPort.h"

#ifdef USE_VFORK
#define fork vfork
#endif

/*
 * The following macros convert between TclFile's and fd's.  The conversion
 * simple involves shifting fd's up by one to ensure that no valid fd is ever
 * the same as NULL.
 */

#define MakeFile(fd) ((TclFile)(((int)fd)+1))
#define GetFd(file) (((int)file)-1)

/*
 * This structure describes per-instance state of a pipe based channel.
 */

typedef struct PipeState {
    Tcl_Channel channel;/* Channel associated with this file. */
    TclFile inFile;	/* Output from pipe. */
    TclFile outFile;	/* Input to pipe. */
    TclFile errorFile;	/* Error output from pipe. */
    int numPids;	/* How many processes are attached to this pipe? */
    Tcl_Pid *pidPtr;	/* The process IDs themselves. Allocated by
                         * the creator of the pipe. */
    int isNonBlocking;	/* Nonzero when the pipe is in nonblocking mode.
                         * Used to decide whether to wait for the children
                         * at close time. */
} PipeState;

/*
 * Declarations for local procedures defined in this file:
 */

static int	PipeBlockModeProc _ANSI_ARGS_((ClientData instanceData,
		    int mode));
static int	PipeCloseProc _ANSI_ARGS_((ClientData instanceData,
		    Tcl_Interp *interp));
static int	PipeGetHandleProc _ANSI_ARGS_((ClientData instanceData,
		    int direction, ClientData *handlePtr));
static int	PipeInputProc _ANSI_ARGS_((ClientData instanceData,
		    char *buf, int toRead, int *errorCode));
static int	PipeOutputProc _ANSI_ARGS_((
		    ClientData instanceData, CONST char *buf, int toWrite,
		    int *errorCode));
static void	PipeWatchProc _ANSI_ARGS_((ClientData instanceData, int mask));
static void	RestoreSignals _ANSI_ARGS_((void));
static int	SetupStdFile _ANSI_ARGS_((TclFile file, int type));

/*
 * This structure describes the channel type structure for command pipe
 * based IO:
 */

static Tcl_ChannelType pipeChannelType = {
    "pipe",			/* Type name. */
    TCL_CHANNEL_VERSION_2,	/* v2 channel */
    PipeCloseProc,		/* Close proc. */
    PipeInputProc,		/* Input proc. */
    PipeOutputProc,		/* Output proc. */
    NULL,			/* Seek proc. */
    NULL,			/* Set option proc. */
    NULL,			/* Get option proc. */
    PipeWatchProc,		/* Initialize notifier. */
    PipeGetHandleProc,		/* Get OS handles out of channel. */
    NULL,			/* close2proc. */
    PipeBlockModeProc,		/* Set blocking or non-blocking mode.*/
    NULL,			/* flush proc. */
    NULL,			/* handler proc. */
};

/*
 *----------------------------------------------------------------------
 *
 * TclpMakeFile --
 *
 *	Make a TclFile from a channel.
 *
 * Results:
 *	Returns a new TclFile or NULL on failure.
 *
 * Side effects:
 *	None.
 *
 *----------------------------------------------------------------------
 */

TclFile
TclpMakeFile(channel, direction)
    Tcl_Channel channel;	/* Channel to get file from. */
    int direction;		/* Either TCL_READABLE or TCL_WRITABLE. */
{
    ClientData data;

    if (Tcl_GetChannelHandle(channel, direction, (ClientData *) &data)
	    == TCL_OK) {
	return MakeFile((int)data);
    } else {
	return (TclFile) NULL;
    }
}

/*
 *----------------------------------------------------------------------
 *
 * TclpOpenFile --
 *
 *	Open a file for use in a pipeline.  
 *
 * Results:
 *	Returns a new TclFile handle or NULL on failure.
 *
 * Side effects:
 *	May cause a file to be created on the file system.
 *
 *----------------------------------------------------------------------
 */

TclFile
TclpOpenFile(fname, mode)
    CONST char *fname;		/* The name of the file to open. */
    int mode;			/* In what mode to open the file? */
{
    int fd;
    CONST char *native;
    Tcl_DString ds;

    native = Tcl_UtfToExternalDString(NULL, fname, -1, &ds);
    fd = TclOSopen(native, mode, 0666);			/* INTL: Native. */
    Tcl_DStringFree(&ds);
    if (fd != -1) {
        fcntl(fd, F_SETFD, FD_CLOEXEC);

	/*
	 * If the file is being opened for writing, seek to the end
	 * so we can append to any data already in the file.
	 */

	if (mode & O_WRONLY) {
	    TclOSseek(fd, (Tcl_SeekOffset) 0, SEEK_END);
	}

	/*
	 * Increment the fd so it can't be 0, which would conflict with
	 * the NULL return for errors.
	 */

	return MakeFile(fd);
    }
    return NULL;
}

/*
 *----------------------------------------------------------------------
 *
 * TclpCreateTempFile --
 *
 *	This function creates a temporary file initialized with an
 *	optional string, and returns a file handle with the file pointer
 *	at the beginning of the file.
 *
 * Results:
 *	A handle to a file.
 *
 * Side effects:
 *	None.
 *
 *----------------------------------------------------------------------
 */

TclFile
TclpCreateTempFile(contents)
    CONST char *contents;	/* String to write into temp file, or NULL. */
{
    char fileName[L_tmpnam + 9];
    CONST char *native;
    Tcl_DString dstring;
    int fd;

    /*
     * We should also check against making more then TMP_MAX of these.
     */

    strcpy(fileName, P_tmpdir);				/* INTL: Native. */
    if (fileName[strlen(fileName) - 1] != '/') {
	strcat(fileName, "/");				/* INTL: Native. */
    }
    strcat(fileName, "tclXXXXXX");
    fd = mkstemp(fileName);				/* INTL: Native. */
    if (fd == -1) {
	return NULL;
    }
    fcntl(fd, F_SETFD, FD_CLOEXEC);
    unlink(fileName);					/* INTL: Native. */

    if (contents != NULL) {
	native = Tcl_UtfToExternalDString(NULL, contents, -1, &dstring);
	if (write(fd, native, strlen(native)) == -1) {
	    close(fd);
	    Tcl_DStringFree(&dstring);
	    return NULL;
	}
	Tcl_DStringFree(&dstring);
	TclOSseek(fd, (Tcl_SeekOffset) 0, SEEK_SET);
    }
    return MakeFile(fd);
}

/*
 *----------------------------------------------------------------------
 *
 * TclpTempFileName --
 *
 *	This function returns unique filename.
 *
 * Results:
 *	Returns a valid Tcl_Obj* with refCount 0, or NULL on failure.
 *
 * Side effects:
 *	None.
 *
 *----------------------------------------------------------------------
 */

Tcl_Obj* 
TclpTempFileName()
{
    char fileName[L_tmpnam + 9];
    Tcl_Obj *result = NULL;
    int fd;

    /*
     * We should also check against making more then TMP_MAX of these.
     */

    strcpy(fileName, P_tmpdir);		/* INTL: Native. */
    if (fileName[strlen(fileName) - 1] != '/') {
	strcat(fileName, "/");		/* INTL: Native. */
    }
    strcat(fileName, "tclXXXXXX");
    fd = mkstemp(fileName);		/* INTL: Native. */
    if (fd == -1) {
	return NULL;
    }
    fcntl(fd, F_SETFD, FD_CLOEXEC);
    unlink(fileName);			/* INTL: Native. */

    result = TclpNativeToNormalized((ClientData) fileName);
    close (fd);
    return result;
}

/*
 *----------------------------------------------------------------------
 *
 * TclpCreatePipe --
 *
 *      Creates a pipe - simply calls the pipe() function.
 *
 * Results:
 *      Returns 1 on success, 0 on failure. 
 *
 * Side effects:
 *      Creates a pipe.
 *
 *----------------------------------------------------------------------
 */

int
TclpCreatePipe(readPipe, writePipe)
    TclFile *readPipe;		/* Location to store file handle for
				 * read side of pipe. */
    TclFile *writePipe;		/* Location to store file handle for
				 * write side of pipe. */
{
    int pipeIds[2];

    if (pipe(pipeIds) != 0) {
	return 0;
    }

    fcntl(pipeIds[0], F_SETFD, FD_CLOEXEC);
    fcntl(pipeIds[1], F_SETFD, FD_CLOEXEC);

    *readPipe = MakeFile(pipeIds[0]);
    *writePipe = MakeFile(pipeIds[1]);
    return 1;
}

/*
 *----------------------------------------------------------------------
 *
 * TclpCloseFile --
 *
 *	Implements a mechanism to close a UNIX file.
 *
 * Results:
 *	Returns 0 on success, or -1 on error, setting errno.
 *
 * Side effects:
 *	The file is closed.
 *
 *----------------------------------------------------------------------
 */

int
TclpCloseFile(file)
    TclFile file;	/* The file to close. */
{
    int fd = GetFd(file);

    /*
     * Refuse to close the fds for stdin, stdout and stderr.
     */
    
    if ((fd == 0) || (fd == 1) || (fd == 2)) {
        return 0;
    }
    
    Tcl_DeleteFileHandler(fd);
    return close(fd);
}

/*
 *---------------------------------------------------------------------------
 *
 * TclpCreateProcess --
 *
 *	Create a child process that has the specified files as its 
 *	standard input, output, and error.  The child process runs
 *	asynchronously and runs with the same environment variables
 *	as the creating process.
 *
 *	The path is searched to find the specified executable.  
 *
 * Results:
 *	The return value is TCL_ERROR and an error message is left in
 *	the interp's result if there was a problem creating the child 
 *	process.  Otherwise, the return value is TCL_OK and *pidPtr is
 *	filled with the process id of the child process.
 * 
 * Side effects:
 *	A process is created.
 *	
 *---------------------------------------------------------------------------
 */

    /* ARGSUSED */
int
TclpCreateProcess(interp, argc, argv, inputFile, outputFile, errorFile, 
	pidPtr)
    Tcl_Interp *interp;		/* Interpreter in which to leave errors that
				 * occurred when creating the child process.
				 * Error messages from the child process
				 * itself are sent to errorFile. */
    int argc;			/* Number of arguments in following array. */
    CONST char **argv;		/* Array of argument strings in UTF-8.
				 * argv[0] contains the name of the executable
				 * translated using Tcl_TranslateFileName
				 * call).  Additional arguments have not been
				 * converted. */
    TclFile inputFile;		/* If non-NULL, gives the file to use as
				 * input for the child process.  If inputFile
				 * file is not readable or is NULL, the child
				 * will receive no standard input. */
    TclFile outputFile;		/* If non-NULL, gives the file that
				 * receives output from the child process.  If
				 * outputFile file is not writeable or is
				 * NULL, output from the child will be
				 * discarded. */
    TclFile errorFile;		/* If non-NULL, gives the file that
				 * receives errors from the child process.  If
				 * errorFile file is not writeable or is NULL,
				 * errors from the child will be discarded.
				 * errorFile may be the same as outputFile. */
    Tcl_Pid *pidPtr;		/* If this procedure is successful, pidPtr
				 * is filled with the process id of the child
				 * process. */
{
    TclFile errPipeIn, errPipeOut;
    int joinThisError, count, status, fd;
    char errSpace[200 + TCL_INTEGER_SPACE];
    Tcl_DString *dsArray;
    char **newArgv;
    int pid, i;
    
    errPipeIn = NULL;
    errPipeOut = NULL;
    pid = -1;

    /*
     * Create a pipe that the child can use to return error
     * information if anything goes wrong.
     */

    if (TclpCreatePipe(&errPipeIn, &errPipeOut) == 0) {
	Tcl_AppendResult(interp, "couldn't create pipe: ",
		Tcl_PosixError(interp), (char *) NULL);
	goto error;