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      1 /*	$NetBSD: compat_dup3.c,v 1.4 2025/08/06 23:51:16 kre Exp $ */
      2 
      3 /*-
      4  * Copyright (c) 2024 The NetBSD Foundation, Inc.
      5  * All rights reserved.
      6  *
      7  * This code is derived from software contributed to The NetBSD Foundation
      8  * by Christos Zoulas.
      9  *
     10  * Redistribution and use in source and binary forms, with or without
     11  * modification, are permitted provided that the following conditions
     12  * are met:
     13  * 1. Redistributions of source code must retain the above copyright
     14  *    notice, this list of conditions and the following disclaimer.
     15  * 2. Redistributions in binary form must reproduce the above copyright
     16  *    notice, this list of conditions and the following disclaimer in the
     17  *    documentation and/or other materials provided with the distribution.
     18  *
     19  * THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. AND CONTRIBUTORS
     20  * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED
     21  * TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
     22  * PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL THE FOUNDATION OR CONTRIBUTORS
     23  * BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
     24  * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
     25  * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
     26  * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
     27  * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
     28  * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
     29  * POSSIBILITY OF SUCH DAMAGE.
     30  */
     31 #include <sys/cdefs.h>
     32 #if defined(LIBC_SCCS) && !defined(lint)
     33 __RCSID("$NetBSD: compat_dup3.c,v 1.4 2025/08/06 23:51:16 kre Exp $");
     34 #endif /* LIBC_SCCS and not lint */
     35 
     36 #include "namespace.h"
     37 #define __LIBC12_SOURCE__
     38 #include <fcntl.h>
     39 #include <compat/include/unistd.h>
     40 
     41 __warn_references(dup3,
     42     "warning: reference to compatibility dup3(); include <unistd.h> to generate correct reference")
     43 
     44 int
     45 dup3(int oldfd, int newfd, int flags)
     46 {
     47 	int fdflags;
     48 
     49 	if (oldfd != newfd) {
     50 		return __dup3100(oldfd, newfd, flags);
     51 	}
     52 	if (flags & (O_NONBLOCK|O_NOSIGPIPE)) {
     53 		int e = fcntl(newfd, F_GETFL, 0);
     54 		if (e == -1)
     55 			return -1;
     56 		e |= flags & (O_NONBLOCK|O_NOSIGPIPE);
     57 		e = fcntl(newfd, F_SETFL, e);
     58 		if (e == -1)
     59 			return -1;
     60 	}
     61 
     62 	switch (flags & (O_CLOEXEC|O_CLOFORK)) {
     63 	case O_CLOEXEC|O_CLOFORK:
     64 		fdflags = FD_CLOEXEC|FD_CLOFORK;
     65 		break;
     66 	case O_CLOEXEC:
     67 		fdflags = FD_CLOEXEC;
     68 		break;
     69 	case O_CLOFORK:
     70 		fdflags = FD_CLOFORK;
     71 		break;
     72 	default:
     73 		return 0;
     74 	}
     75 	return fcntl(newfd, F_SETFD, fdflags);
     76 }
     77