adtools/clib2

/*
 * $Id: unistd_dup2.c,v 1.10 2006-01-08 12:04:27 obarthel Exp $
 *
 * :ts=4
 *
 * Portable ISO 'C' (1994) runtime library for the Amiga computer
 * Copyright (c) 2002-2015 by Olaf Barthel <obarthel (at) gmx.net>
 * All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 *
 *   - Redistributions of source code must retain the above copyright
 *     notice, this list of conditions and the following disclaimer.
 *
 *   - Neither the name of Olaf Barthel nor the names of contributors
 *     may be used to endorse or promote products derived from this
 *     software without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS 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 COPYRIGHT OWNER 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.
 */

#ifndef _UNISTD_HEADERS_H
#include "unistd_headers.h"
#endif /* _UNISTD_HEADERS_H */

/****************************************************************************/

/* The following is not part of the ISO 'C' (1994) standard. */

/****************************************************************************/

int
dup2(int file_descriptor1, int file_descriptor2)
{
    struct fd * fd1;
    int result = ERROR;

    ENTER();

    SHOWVALUE(file_descriptor1);
    SHOWVALUE(file_descriptor2);

    if(__check_abort_enabled)
        __check_abort();

    __stdio_lock();

    assert( file_descriptor1 >= 0 && file_descriptor1 < __num_fd );
    assert( __fd[file_descriptor1] != NULL );
    assert( FLAG_IS_SET(__fd[file_descriptor1]->fd_Flags,FDF_IN_USE) );

    fd1 = __get_file_descriptor(file_descriptor1);
    if(fd1 == NULL)
    {
        __set_errno(EBADF);
        goto out;
    }

    if(file_descriptor2 < 0)
    {
        /* Try to find a place to put the duplicate into. */
        file_descriptor2 = __find_vacant_fd_entry();
        if(file_descriptor2 < 0)
        {
            /* No free space, so let's grow the table. */
            if(__grow_fd_table(0) < 0)
            {
                SHOWMSG("not enough memory for new file descriptor");
                goto out;
            }

            file_descriptor2 = __find_vacant_fd_entry();
            assert( file_descriptor2 >= 0 );
        }
    }
    else if (file_descriptor1 != file_descriptor2)
    {
        /* Make sure the requested duplicate exists. */
        if(__grow_fd_table(file_descriptor2 + 1) < 0)
            goto out;

        assert( file_descriptor2 >= 0 && file_descriptor2 < __num_fd );
        assert( __fd[file_descriptor2] != NULL );
    }

    if(file_descriptor1 != file_descriptor2)
    {
        struct fd * fd2;

        /* Have a look at the requested file descriptor. */
        assert( 0 <= file_descriptor2 && file_descriptor2 < __num_fd );

        fd2 = __fd[file_descriptor2];

        assert( fd2 != NULL );

        /* Make sure that the entry is cleaned up before we used it. */
        if(FLAG_IS_SET(fd2->fd_Flags,FDF_IN_USE))
        {
            SHOWMSG("closing file descriptor #2");

            if(close(file_descriptor2) < 0)
                goto out;
        }

        __duplicate_fd(fd2,fd1);
    }

    result = file_descriptor2;

 out:

    __stdio_unlock();

    RETURN(result);
    return(result);
}