gno/lib/libc/gen/popen.c

/*
 * Copyright (c) 1988 The Regents of the University of California.
 * All rights reserved.
 *
 * This code is derived from software written by Ken Arnold and
 * published in UNIX Review, Vol. 6, No. 8.
 *
 * 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. All advertising materials mentioning features or use of this software
 *    must display the following acknowledgement:
 * This product includes software developed by the University of
 * California, Berkeley and its contributors.
 * 4. Neither the name of the University nor the names of its contributors
 *    may be used to endorse or promote products derived from this software
 *    without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
 * ANY EXPRESS 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 THE REGENTS OR 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.
 */

#ifdef __ORCAC__
segment "libc_gen__";
#endif

#pragma optimize 0
#pragma debug 0
#pragma memorymodel 0

#if defined(LIBC_SCCS) && !defined(lint)
static char *sccsid = "from: @(#)popen.c   5.15 (Berkeley) 2/23/91";
static char *rcsid = "popen.c,v 1.5 1993/08/26 00:44:55 jtc Exp";
#endif /* LIBC_SCCS and not lint */

#include <sys/param.h>
#include <sys/types.h>
#include <sys/wait.h>
#include <errno.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <unistd.h>
#include <paths.h>
#include <assert.h>

static pid_t *pids;

#ifdef __GNO__
#pragma databank 1
static void 
_popen_child(int *pdes, char type, char *command)
{
	if (type == 'r') {
		if (pdes[1] != STDOUT_FILENO) {
			(void) dup2(pdes[1], STDOUT_FILENO);
			(void) close(pdes[1]);
		}
		(void) close(pdes[0]);
	} else {
		if (pdes[0] != STDIN_FILENO) {
			(void) dup2(pdes[0], STDIN_FILENO);
			(void) close(pdes[0]);
		}
		(void) close(pdes[1]);
	}

	/* change this when we have an sh(1) for GNO */
#if 1
	execl(_PATH_GSHELL, "gsh", "-c", command, (char *) 0);
#else
	execl(_PATH_BSHELL, "sh", "-c", command, (char *) 0);
#endif
	_exit(127);
}
#pragma databank 0

#endif /* __GNO__ */

FILE *
popen(const char *command, const char *type)
{
	FILE *iop;
	int fds, pid;
	int pdes[2];

	if (*type != 'r' && *type != 'w' || type[1]) {
		errno = EINVAL;
		return (NULL);
	}
	if (pids == NULL) {
		if ((fds = getdtablesize()) <= 0) {
			return (NULL);
		}
		if ((pids = malloc(fds * sizeof(int))) == NULL) {
			return NULL;
		}
		bzero((char *) pids, fds * sizeof(pid_t));
	}
	if (pipe(pdes) < 0) {
		return (NULL);
	}

#ifdef __GNO__
	pid = fork2(_popen_child, 1024, 0, "forked child of popen", 5,
		    pdes, *type, command);
	switch (pid) {
#else
	switch (pid = vfork()) {
#endif

	case -1:                    /* error */
		(void) close(pdes[0]);
		(void) close(pdes[1]);
		return (NULL);
		/* NOTREACHED */

#ifndef __GNO__
	case 0:                     /* child */
		if (*type == 'r') {
			if (pdes[1] != STDOUT_FILENO) {
				(void) dup2(pdes[1], STDOUT_FILENO);
				(void) close(pdes[1]);
			}
			(void) close(pdes[0]);
		} else {
			if (pdes[0] != STDIN_FILENO) {
				(void) dup2(pdes[0], STDIN_FILENO);
				(void) close(pdes[0]);
			}
			(void) close(pdes[1]);
		}
		execl(_PATH_BSHELL, "sh", "-c", command, (char *) 0);
		_exit(127);
		/* NOTREACHED */
#endif /* ! __GNO__ */
	}
	/* parent; assume fdopen can't fail...  */
	if (*type == 'r') {
		iop = fdopen(pdes[0], type);
		(void) close(pdes[1]);
	} else {
		iop = fdopen(pdes[1], type);
		(void) close(pdes[0]);
	}

	/*
	 * this assert may be removed when getdtablesize is replaced by
	 * a kernel system call rather than just a stub returning OPEN_MAX
	 */
	assert(fileno(iop) < getdtablesize());

	pids[fileno(iop)] = pid;
	return (iop);
}

int 
pclose(FILE * iop)
{
	register int fdes;
	int omask;
	union wait pstat;
	pid_t pid;


	/*
	 * this assert may be removed when getdtablesize is replaced by
	 * a kernel system call rather than just a stub returning OPEN_MAX
	 */
	assert(fileno(iop) < getdtablesize());

	/*
	 * pclose returns -1 if stream is not associated with a
	 * `popened' command, if already `pclosed', or waitpid
	 * returns an error.
	 */
	fdes = fileno(iop);
	if (pids == NULL || pids[fdes] == 0) {
		return (-1);
	}
	(void) fclose(iop);
	do {
		pid = waitpid(pids[fdes], &pstat, 0);
	} while (pid == -1 && errno == EINTR);
	pids[fdes] = 0;
	return (pid == -1 ? -1 : pstat.w_retcode);
}