1  /* Copyright (C) 2008-2023 Free Software Foundation, Inc.
       2     This file is part of the GNU C Library.
       3  
       4     The GNU C Library is free software; you can redistribute it and/or
       5     modify it under the terms of the GNU Lesser General Public
       6     License as published by the Free Software Foundation; either
       7     version 2.1 of the License, or (at your option) any later version.
       8  
       9     The GNU C Library is distributed in the hope that it will be useful,
      10     but WITHOUT ANY WARRANTY; without even the implied warranty of
      11     MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
      12     Lesser General Public License for more details.
      13  
      14     You should have received a copy of the GNU Lesser General Public
      15     License along with the GNU C Library; if not, see
      16     <https://www.gnu.org/licenses/>.  */
      17  
      18  #include <errno.h>
      19  #include <fcntl.h>
      20  #include <unistd.h>
      21  
      22  
      23  /* Duplicate FD to FD2, closing the old FD2 and making FD2 be
      24     open the same file as FD is which setting flags according to
      25     FLAGS.  Return FD2 or -1.  */
      26  int
      27  __dup3 (int fd, int fd2, int flags)
      28  {
      29    if (fd < 0 || fd2 < 0)
      30      {
      31        __set_errno (EBADF);
      32        return -1;
      33      }
      34  
      35    if (fd == fd2)
      36      /* No way to check that they are valid.  */
      37      return fd2;
      38  
      39    __set_errno (ENOSYS);
      40    return -1;
      41  }
      42  libc_hidden_def (__dup3)
      43  weak_alias (__dup3, dup3)
      44  stub_warning (dup3)