/*
* CDDL HEADER START
*
* The contents of this file are subject to the terms of the
* Common Development and Distribution License (the "License").
* You may not use this file except in compliance with the License.
*
* You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE
* or http://www.opensolaris.org/os/licensing.
* See the License for the specific language governing permissions
* and limitations under the License.
*
* When distributing Covered Code, include this CDDL HEADER in each
* file and include the License file at usr/src/OPENSOLARIS.LICENSE.
* If applicable, add the following below this CDDL HEADER, with the
* fields enclosed by brackets "[]" replaced with your own identifying
* information: Portions Copyright [yyyy] [name of copyright owner]
*
* CDDL HEADER END
*/
/*
* Copyright 2006 Sun Microsystems, Inc. All rights reserved.
* Use is subject to license terms.
*/
#pragma ident "%Z%%M% %I% %E% SMI"
#include <fcntl.h>
#include <unistd.h>
#include <sys/syscall.h>
#include <errno.h>
#define OPEN_MAX 20 /* Taken from SVR4 limits.h */
int
dup2(
int fildes, /* file descriptor to be duplicated */
int fildes2) /* desired file descriptor */
{
int tmperrno; /* local work area */
int open_max; /* max open files */
int ret; /* return value */
int fds; /* duplicate files descriptor */
if ((open_max = ulimit(4, 0)) < 0)
open_max = OPEN_MAX; /* take a guess */
/* Be sure fildes is valid and open */
if (fcntl(fildes, F_GETFL, 0) == -1) {
errno = EBADF;
return (-1);
}
/* Be sure fildes2 is in valid range */
if (fildes2 < 0 || fildes2 >= open_max) {
errno = EBADF;
return (-1);
}
/* Check if file descriptors are equal */
if (fildes == fildes2) {
/* open and equal so no dup necessary */
return (fildes2);
}
/* Close in case it was open for another file */
/* Must save and restore errno in case file was not open */
tmperrno = errno;
close(fildes2);
errno = tmperrno;
/* Do the dup */
if ((ret = fcntl(fildes, F_DUPFD, fildes2)) != -1) {
if ((fds = fd_get(fildes)) != -1)
fd_add(fildes2, fds);
}
return (ret);
}