1 /* 2 * CDDL HEADER START 3 * 4 * The contents of this file are subject to the terms of the 5 * Common Development and Distribution License, Version 1.0 only 6 * (the "License"). You may not use this file except in compliance 7 * with the License. 8 * 9 * You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE 10 * or http://www.opensolaris.org/os/licensing. 11 * See the License for the specific language governing permissions 12 * and limitations under the License. 13 * 14 * When distributing Covered Code, include this CDDL HEADER in each 15 * file and include the License file at usr/src/OPENSOLARIS.LICENSE. 16 * If applicable, add the following below this CDDL HEADER, with the 17 * fields enclosed by brackets "[]" replaced with your own identifying 18 * information: Portions Copyright [yyyy] [name of copyright owner] 19 * 20 * CDDL HEADER END 21 */ 22 /* 23 * Copyright 1990 Sun Microsystems, Inc. All rights reserved. 24 * Use is subject to license terms. 25 */ 26 27 #pragma ident "%Z%%M% %I% %E% SMI" 28 29 #include <fcntl.h> 30 #include <unistd.h> 31 #include <syscall.h> 32 #include <sys/errno.h> 33 34 #define OPEN_MAX 20 /* Taken from SVR4 limits.h */ 35 36 int dup2(fildes, fildes2) 37 int fildes, /* file descriptor to be duplicated */ 38 fildes2; /* desired file descriptor */ 39 { 40 int tmperrno; /* local work area */ 41 register int open_max; /* max open files */ 42 extern int errno; /* system error indicator */ 43 int ret; /* return value */ 44 int fds; /* duplicate files descriptor */ 45 46 if ((open_max = ulimit(4, 0)) < 0) 47 open_max = OPEN_MAX; /* take a guess */ 48 49 /* Be sure fildes is valid and open */ 50 if (fcntl(fildes, F_GETFL, 0) == -1) { 51 errno = EBADF; 52 return (-1); 53 } 54 55 /* Be sure fildes2 is in valid range */ 56 if (fildes2 < 0 || fildes2 >= open_max) { 57 errno = EBADF; 58 return (-1); 59 } 60 61 /* Check if file descriptors are equal */ 62 if (fildes == fildes2) { 63 /* open and equal so no dup necessary */ 64 return (fildes2); 65 } 66 /* Close in case it was open for another file */ 67 /* Must save and restore errno in case file was not open */ 68 tmperrno = errno; 69 close(fildes2); 70 errno = tmperrno; 71 72 /* Do the dup */ 73 if ((ret = fcntl(fildes, F_DUPFD, fildes2)) != -1) { 74 if ((fds = fd_get(fildes)) != -1) 75 fd_add(fildes2, fds); 76 } 77 return(ret); 78 79 } 80