#ifndef lint
static const char	RCSid[] = "$Id: process.c,v 2.5 2003/02/22 02:07:22 greg Exp $";
#endif
/*
 * Routines to communicate with separate process via dual pipes
 *
 * External symbols declared in standard.h
 */

/* ====================================================================
 * The Radiance Software License, Version 1.0
 *
 * Copyright (c) 1990 - 2002 The Regents of the University of California,
 * through Lawrence Berkeley National Laboratory.   All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 *
 * 1. Redistributions of source code must retain the above copyright
 *         notice, this list of conditions and the following disclaimer.
 *
 * 2. Redistributions in binary form must reproduce the above copyright
 *       notice, this list of conditions and the following disclaimer in
 *       the documentation and/or other materials provided with the
 *       distribution.
 *
 * 3. The end-user documentation included with the redistribution,
 *           if any, must include the following acknowledgment:
 *             "This product includes Radiance software
 *                 (http://radsite.lbl.gov/)
 *                 developed by the Lawrence Berkeley National Laboratory
 *               (http://www.lbl.gov/)."
 *       Alternately, this acknowledgment may appear in the software itself,
 *       if and wherever such third-party acknowledgments normally appear.
 *
 * 4. The names "Radiance," "Lawrence Berkeley National Laboratory"
 *       and "The Regents of the University of California" must
 *       not be used to endorse or promote products derived from this
 *       software without prior written permission. For written
 *       permission, please contact radiance@radsite.lbl.gov.
 *
 * 5. Products derived from this software may not be called "Radiance",
 *       nor may "Radiance" appear in their name, without prior written
 *       permission of Lawrence Berkeley National Laboratory.
 *
 * THIS SOFTWARE IS PROVIDED ``AS IS'' AND ANY EXPRESSED OR IMPLIED
 * WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
 * DISCLAIMED.   IN NO EVENT SHALL Lawrence Berkeley National Laboratory OR
 * ITS CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
 * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
 * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF
 * USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND
 * ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
 * OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT
 * OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
 * SUCH DAMAGE.
 * ====================================================================
 *
 * This software consists of voluntary contributions made by many
 * individuals on behalf of Lawrence Berkeley National Laboratory.   For more
 * information on Lawrence Berkeley National Laboratory, please see
 * <http://www.lbl.gov/>.
 */

				/* find pipe buffer limit */
#include  <sys/param.h>

#ifndef PIPE_BUF
#ifdef PIPSIZ
#define PIPE_BUF	PIPSIZ
#else
#ifdef PIPE_MAX
#define PIPE_BUF	PIPE_MAX
#else
#define PIPE_BUF	512		/* hyperconservative */
#endif
#endif
#endif

#include  "vfork.h"

#ifndef BSD
#include  <errno.h>
#endif


int
open_process(pd, av)		/* open communication to separate process */
int	pd[3];
char	*av[];
{
	extern char	*getpath(), *getenv();
	char	*compath;
	int	p0[2], p1[2];
					/* find executable */
	compath = getpath(av[0], getenv("PATH"), 1);
	if (compath == 0)
		return(0);
	if (pipe(p0) < 0 || pipe(p1) < 0)
		return(-1);
	if ((pd[2] = vfork()) == 0) {		/* if child */
		close(p0[1]);
		close(p1[0]);
		if (p0[0] != 0) {	/* connect p0 to stdin */
			dup2(p0[0], 0);
			close(p0[0]);
		}
		if (p1[1] != 1) {	/* connect p1 to stdout */
			dup2(p1[1], 1);
			close(p1[1]);
		}
		execv(compath, av);	/* exec command */
		perror(compath);
		_exit(127);
	}
	if (pd[2] == -1)
		return(-1);
	close(p0[0]);
	close(p1[1]);
	pd[0] = p1[0];
	pd[1] = p0[1];
	return(PIPE_BUF);
}


int
process(pd, recvbuf, sendbuf, nbr, nbs)		/* process data through pd */
int	pd[3];
char	*recvbuf, *sendbuf;
int	nbr, nbs;
{
	if (nbs > PIPE_BUF)
		return(-1);
	if (writebuf(pd[1], sendbuf, nbs) < nbs)
		return(-1);
	return(readbuf(pd[0], recvbuf, nbr));
}


int
close_process(pd)		/* close pipes and wait for process */
int	pd[3];
{
	int	pid, status;

	close(pd[1]);
	close(pd[0]);
	while ((pid = wait(&status)) != -1)
		if (pid == pd[2])
			return(status>>8 & 0xff);
	return(-1);		/* ? unknown status */
}


int
readbuf(fd, bpos, siz)		/* read all of requested buffer */
int	fd;
char	*bpos;
int	siz;
{
	register int	cc = 0, nrem = siz;
retry:
	while (nrem > 0 && (cc = read(fd, bpos, nrem)) > 0) {
		bpos += cc;
		nrem -= cc;
	}
	if (cc < 0) {
#ifndef BSD
		if (errno == EINTR)	/* we were interrupted! */
			goto retry;
#endif
		return(cc);
	}
	return(siz-nrem);
}


int
writebuf(fd, bpos, siz)		/* write all of requested buffer */
int	fd;
char	*bpos;
int	siz;
{
	register int	cc = 0, nrem = siz;
retry:
	while (nrem > 0 && (cc = write(fd, bpos, nrem)) > 0) {
		bpos += cc;
		nrem -= cc;
	}
	if (cc < 0) {
#ifndef BSD
		if (errno == EINTR)	/* we were interrupted! */
			goto retry;
#endif
		return(cc);
	}
	return(siz-nrem);
}