+
−/* Duplicate an open file descriptor to a specified file descriptor.
+
−
+
−   Copyright (C) 1999, 2004-2007, 2009-2012 Free Software Foundation, Inc.
+
−
+
−   This program is free software: you can redistribute it and/or modify
+
−   it under the terms of the GNU General Public License as published by
+
−   the Free Software Foundation; either version 3 of the License, or
+
−   (at your option) any later version.
+
−
+
−   This program is distributed in the hope that it will be useful,
+
−   but WITHOUT ANY WARRANTY; without even the implied warranty of
+
−   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+
−   GNU General Public License for more details.
+
−
+
−   You should have received a copy of the GNU General Public License
+
−   along with this program.  If not, see <http://www.gnu.org/licenses/>.  */
+
−
+
−/* written by Paul Eggert */
+
−
+
−#include <config.h>
+
−
+
−/* Specification.  */
+
−#include <unistd.h>
+
−
+
−#include <errno.h>
+
−#include <fcntl.h>
+
−
+
−#if HAVE_DUP2
+
−
+
−# undef dup2
+
−
+
−# if (defined _WIN32 || defined __WIN32__) && ! defined __CYGWIN__
+
−
+
−/* Get declarations of the native Windows API functions.  */
+
−#  define WIN32_LEAN_AND_MEAN
+
−#  include <windows.h>
+
−
+
−#  include "msvc-inval.h"
+
−
+
−/* Get _get_osfhandle.  */
+
−#  include "msvc-nothrow.h"
+
−
+
−static int
+
−ms_windows_dup2 (int fd, int desired_fd)
+
−{
+
−  int result;
+
−
+
−  /* If fd is closed, mingw hangs on dup2 (fd, fd).  If fd is open,
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−     dup2 (fd, fd) returns 0, but all further attempts to use fd in
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−     future dup2 calls will hang.  */
+
−  if (fd == desired_fd)
+
−    {
+
−      if ((HANDLE) _get_osfhandle (fd) == INVALID_HANDLE_VALUE)
+
−        {
+
−          errno = EBADF;
+
−          return -1;
+
−        }
+
−      return fd;
+
−    }
+
−
+
−  /* Wine 1.0.1 return 0 when desired_fd is negative but not -1:
+
−     http://bugs.winehq.org/show_bug.cgi?id=21289 */
+
−  if (desired_fd < 0)
+
−    {
+
−      errno = EBADF;
+
−      return -1;
+
−    }
+
−
+
−  TRY_MSVC_INVAL
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−    {
+
−      result = dup2 (fd, desired_fd);
+
−    }
+
−  CATCH_MSVC_INVAL
+
−    {
+
−      errno = EBADF;
+
−      result = -1;
+
−    }
+
−  DONE_MSVC_INVAL;
+
−
+
−  if (result == 0)
+
−    result = desired_fd;
+
−
+
−  return result;
+
−}
+
−
+
−#  define dup2 ms_windows_dup2
+
−
+
−# endif
+
−
+
−int
+
−rpl_dup2 (int fd, int desired_fd)
+
−{
+
−  int result;
+
−
+
−# ifdef F_GETFL
+
−  /* On Linux kernels 2.6.26-2.6.29, dup2 (fd, fd) returns -EBADF.
+
−     On Cygwin 1.5.x, dup2 (1, 1) returns 0.
+
−     On Haiku, dup2 (fd, fd) mistakenly clears FD_CLOEXEC.  */
+
−  if (fd == desired_fd)
+
−    return fcntl (fd, F_GETFL) == -1 ? -1 : fd;
+
−# endif
+
−
+
−  result = dup2 (fd, desired_fd);
+
−
+
−  /* Correct an errno value on FreeBSD 6.1 and Cygwin 1.5.x.  */
+
−  if (result == -1 && errno == EMFILE)
+
−    errno = EBADF;
+
−# if REPLACE_FCHDIR
+
−  if (fd != desired_fd && result != -1)
+
−    result = _gl_register_dup (fd, result);
+
−# endif
+
−  return result;
+
−}
+
−
+
−#else /* !HAVE_DUP2 */
+
−
+
−/* On older platforms, dup2 did not exist.  */
+
−
+
−# ifndef F_DUPFD
+
−static int
+
−dupfd (int fd, int desired_fd)
+
−{
+
−  int duplicated_fd = dup (fd);
+
−  if (duplicated_fd < 0 || duplicated_fd == desired_fd)
+
−    return duplicated_fd;
+
−  else
+
−    {
+
−      int r = dupfd (fd, desired_fd);
+
−      int e = errno;
+
−      close (duplicated_fd);
+
−      errno = e;
+
−      return r;
+
−    }
+
−}
+
−# endif
+
−
+
−int
+
−dup2 (int fd, int desired_fd)
+
−{
+
−  int result = fcntl (fd, F_GETFL) < 0 ? -1 : fd;
+
−  if (result == -1 || fd == desired_fd)
+
−    return result;
+
−  close (desired_fd);
+
−# ifdef F_DUPFD
+
−  result = fcntl (fd, F_DUPFD, desired_fd);
+
−#  if REPLACE_FCHDIR
+
−  if (0 <= result)
+
−    result = _gl_register_dup (fd, result);
+
−#  endif
+
−# else
+
−  result = dupfd (fd, desired_fd);
+
−# endif
+
−  if (result == -1 && (errno == EMFILE || errno == EINVAL))
+
−    errno = EBADF;
+
−  return result;
+
−}
+
−#endif /* !HAVE_DUP2 */