freebsd-dev/lib/libc_r/uthread/uthread_dup2.c

/*
 * Copyright (c) 1995-1998 John Birrell <jb@cimlogic.com.au>
 * All rights reserved.
 *
 * 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 John Birrell.
 * 4. Neither the name of the author nor the names of any co-contributors
 *    may be used to endorse or promote products derived from this software
 *    without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY JOHN BIRRELL 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 AUTHOR 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.
 *
 * $FreeBSD$
 */
#include <errno.h>
#include <unistd.h>
#include <pthread.h>
#include "pthread_private.h"

__weak_reference(_dup2, dup2);

int
_dup2(int fd, int newfd)
{
	int             ret;
	int		newfd_opened;

	/* Check if the file descriptor is out of range: */
	if (newfd < 0 || newfd >= _thread_dtablesize ||
	    newfd == _thread_kern_pipe[0] || newfd == _thread_kern_pipe[1]) {
		/* Return a bad file descriptor error: */
		errno = EBADF;
		ret = -1;
	}

	/* Lock the file descriptor: */
	else if ((ret = _FD_LOCK(fd, FD_RDWR, NULL)) == 0) {
		/* Lock the file descriptor: */
		if (!(newfd_opened = (_thread_fd_table[newfd] != NULL)) || 
		    (ret = _FD_LOCK(newfd, FD_RDWR, NULL)) == 0) {
			/* Perform the 'dup2' syscall: */
			ret = __sys_dup2(fd, newfd);
			if (ret >= 0) {
				/*
				 * If we are duplicating one of the standard
				 * file descriptors, update its flags in the
				 * table of pthread stdio descriptor flags.
				 */
				if (ret < 3) {
					_pthread_stdio_flags[ret] =
					    _thread_fd_table[fd]->flags;
				}
				/* Initialise the file descriptor table entry */
				if (_thread_fd_table_init(ret) != 0) {
					/* Quietly close the file: */
					__sys_close(ret);

					/* Reset the file descriptor: */
					ret = -1;
				} else {
					/*
					 * Save the file open flags so that
					 * they can be checked later: 
					 */
					_thread_fd_setflags(ret,
					    _thread_fd_getflags(fd));
				}
			}

			/* Unlock the file descriptor: */
			if (newfd_opened)
				_FD_UNLOCK(newfd, FD_RDWR);
		}
		/* Unlock the file descriptor: */
		_FD_UNLOCK(fd, FD_RDWR);
	}
	/* Return the completion status: */
	return (ret);
}