10Sstevel@tonic-gate /*
20Sstevel@tonic-gate * CDDL HEADER START
30Sstevel@tonic-gate *
40Sstevel@tonic-gate * The contents of this file are subject to the terms of the
5*3224Sraf * Common Development and Distribution License (the "License").
6*3224Sraf * You may not use this file except in compliance with the License.
70Sstevel@tonic-gate *
80Sstevel@tonic-gate * You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE
90Sstevel@tonic-gate * or http://www.opensolaris.org/os/licensing.
100Sstevel@tonic-gate * See the License for the specific language governing permissions
110Sstevel@tonic-gate * and limitations under the License.
120Sstevel@tonic-gate *
130Sstevel@tonic-gate * When distributing Covered Code, include this CDDL HEADER in each
140Sstevel@tonic-gate * file and include the License file at usr/src/OPENSOLARIS.LICENSE.
150Sstevel@tonic-gate * If applicable, add the following below this CDDL HEADER, with the
160Sstevel@tonic-gate * fields enclosed by brackets "[]" replaced with your own identifying
170Sstevel@tonic-gate * information: Portions Copyright [yyyy] [name of copyright owner]
180Sstevel@tonic-gate *
190Sstevel@tonic-gate * CDDL HEADER END
200Sstevel@tonic-gate */
21*3224Sraf
220Sstevel@tonic-gate /*
23*3224Sraf * Copyright 2006 Sun Microsystems, Inc. All rights reserved.
240Sstevel@tonic-gate * Use is subject to license terms.
250Sstevel@tonic-gate */
260Sstevel@tonic-gate
270Sstevel@tonic-gate #pragma ident "%Z%%M% %I% %E% SMI"
280Sstevel@tonic-gate
290Sstevel@tonic-gate #include <fcntl.h>
300Sstevel@tonic-gate #include <unistd.h>
31*3224Sraf #include <sys/syscall.h>
32*3224Sraf #include <errno.h>
33*3224Sraf
34*3224Sraf #define OPEN_MAX 20 /* Taken from SVR4 limits.h */
350Sstevel@tonic-gate
36*3224Sraf int
dup2(int fildes,int fildes2)37*3224Sraf dup2(
38*3224Sraf int fildes, /* file descriptor to be duplicated */
39*3224Sraf int fildes2) /* desired file descriptor */
400Sstevel@tonic-gate {
41*3224Sraf int tmperrno; /* local work area */
42*3224Sraf int open_max; /* max open files */
43*3224Sraf int ret; /* return value */
44*3224Sraf int fds; /* duplicate files descriptor */
450Sstevel@tonic-gate
46*3224Sraf if ((open_max = ulimit(4, 0)) < 0)
47*3224Sraf open_max = OPEN_MAX; /* take a guess */
480Sstevel@tonic-gate
49*3224Sraf /* Be sure fildes is valid and open */
50*3224Sraf if (fcntl(fildes, F_GETFL, 0) == -1) {
51*3224Sraf errno = EBADF;
52*3224Sraf return (-1);
53*3224Sraf }
540Sstevel@tonic-gate
55*3224Sraf /* Be sure fildes2 is in valid range */
56*3224Sraf if (fildes2 < 0 || fildes2 >= open_max) {
57*3224Sraf errno = EBADF;
58*3224Sraf return (-1);
59*3224Sraf }
600Sstevel@tonic-gate
61*3224Sraf /* Check if file descriptors are equal */
62*3224Sraf if (fildes == fildes2) {
63*3224Sraf /* open and equal so no dup necessary */
64*3224Sraf return (fildes2);
65*3224Sraf }
66*3224Sraf /* Close in case it was open for another file */
67*3224Sraf /* Must save and restore errno in case file was not open */
68*3224Sraf tmperrno = errno;
69*3224Sraf close(fildes2);
70*3224Sraf errno = tmperrno;
710Sstevel@tonic-gate
72*3224Sraf /* Do the dup */
73*3224Sraf if ((ret = fcntl(fildes, F_DUPFD, fildes2)) != -1) {
74*3224Sraf if ((fds = fd_get(fildes)) != -1)
75*3224Sraf fd_add(fildes2, fds);
76*3224Sraf }
77*3224Sraf return (ret);
780Sstevel@tonic-gate }
79