/*
 * Revision Control Information
 *
 * $Source: /vol/opua/opua2/sis/sis-1.2/common/src/utility/RCS/pipefork.c,v $
 * $Author: sis $
 * $Revision: 1.3 $
 * $Date: 22/.0/.1 .2:.2:.2 $
 *
 */
/* LINTLIBRARY */
#include <sys/wait.h>
#include "copyright.h"
#include "port.h"
#include "utility.h"

/*
 * util_pipefork - fork a command and set up pipes to and from
 *
 * Rick L Spickelmier, 3/23/86
 * Richard Rudell, 4/6/86
 * Rick L Spickelmier, 4/30/90, got rid of slimey vfork semantics
 *
 * Returns:
 *   1 for success, with toCommand and fromCommand pointing to the streams
 *   0 for failure
 */

/* ARGSUSED */
int
util_pipefork(argv, toCommand, fromCommand, pid)
char **argv;				/* normal argv argument list */
FILE **toCommand;			/* pointer to the sending stream */
FILE **fromCommand;			/* pointer to the reading stream */
int *pid;
{
#ifdef unix
    int forkpid, waitpid;
    int topipe[2], frompipe[2];
    char buffer[1024];
#if defined(__hpux) || defined (__osf__) || defined(__SVR4) || defined(_POSIX_SOURCE)
    int status;
#else
    union wait status;
#endif

    /* create the PIPES...
     * fildes[0] for reading from command
     * fildes[1] for writing to command
     */
    (void) pipe(topipe);
    (void) pipe(frompipe);

    if ((forkpid = vfork()) == 0) {
	/* child here, connect the pipes */
	(void) dup2(topipe[0], fileno(stdin));
	(void) dup2(frompipe[1], fileno(stdout));

	(void) close(topipe[0]);
	(void) close(topipe[1]);
	(void) close(frompipe[0]);
	(void) close(frompipe[1]);

	(void) execvp(argv[0], argv);
	(void) sprintf(buffer, "util_pipefork: can not exec %s", argv[0]);
	perror(buffer);
	(void) _exit(1);
    }

    if (pid) {
	*pid = forkpid;
    }

    waitpid = wait3(&status, WNOHANG, 0);

    /* parent here, use slimey vfork() semantics to get return status */
    if (waitpid == forkpid && WIFEXITED(status)) {
	return 0;
    }
    if ((*toCommand = fdopen(topipe[1], "w")) == NULL) {
	return 0;
    }
    if ((*fromCommand = fdopen(frompipe[0], "r")) == NULL) {
	return 0;
    }
    (void) close(topipe[0]);
    (void) close(frompipe[1]);
    return 1;
#else
    (void) fprintf(stderr, 
	"util_pipefork: not implemented on your operating system\n");
    return 0;
#endif
}