+
−/* Create a pipe, with specific opening flags.
+
−   Copyright (C) 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 2, 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/>.  */
+
−
+
−#include <config.h>
+
−
+
−/* Specification.  */
+
−#include <unistd.h>
+
−
+
−#include <errno.h>
+
−#include <fcntl.h>
+
−
+
−#include "binary-io.h"
+
−#include "verify.h"
+
−
+
−#if GNULIB_defined_O_NONBLOCK
+
−# include "nonblocking.h"
+
−#endif
+
−
+
−#if (defined _WIN32 || defined __WIN32__) && ! defined __CYGWIN__
+
−/* Native Windows API.  */
+
−
+
−# include <io.h>
+
−
+
−#endif
+
−
+
−int
+
−pipe2 (int fd[2], int flags)
+
−{
+
−  /* Mingw _pipe() corrupts fd on failure; also, if we succeed at
+
−     creating the pipe but later fail at changing fcntl, we want
+
−     to leave fd unchanged: http://austingroupbugs.net/view.php?id=467  */
+
−  int tmp[2];
+
−  tmp[0] = fd[0];
+
−  tmp[1] = fd[1];
+
−
+
−#if HAVE_PIPE2
+
−# undef pipe2
+
−  /* Try the system call first, if it exists.  (We may be running with a glibc
+
−     that has the function but with an older kernel that lacks it.)  */
+
−  {
+
−    /* Cache the information whether the system call really exists.  */
+
−    static int have_pipe2_really; /* 0 = unknown, 1 = yes, -1 = no */
+
−    if (have_pipe2_really >= 0)
+
−      {
+
−        int result = pipe2 (fd, flags);
+
−        if (!(result < 0 && errno == ENOSYS))
+
−          {
+
−            have_pipe2_really = 1;
+
−            return result;
+
−          }
+
−        have_pipe2_really = -1;
+
−      }
+
−  }
+
−#endif
+
−
+
−  /* Check the supported flags.  */
+
−  if ((flags & ~(O_CLOEXEC | O_NONBLOCK | O_BINARY | O_TEXT)) != 0)
+
−    {
+
−      errno = EINVAL;
+
−      return -1;
+
−    }
+
−
+
−#if (defined _WIN32 || defined __WIN32__) && ! defined __CYGWIN__
+
−/* Native Windows API.  */
+
−
+
−  if (_pipe (fd, 4096, flags & ~O_NONBLOCK) < 0)
+
−    {
+
−      fd[0] = tmp[0];
+
−      fd[1] = tmp[1];
+
−      return -1;
+
−    }
+
−
+
−  /* O_NONBLOCK handling.
+
−     On native Windows platforms, O_NONBLOCK is defined by gnulib.  Use the
+
−     functions defined by the gnulib module 'nonblocking'.  */
+
−# if GNULIB_defined_O_NONBLOCK
+
−  if (flags & O_NONBLOCK)
+
−    {
+
−      if (set_nonblocking_flag (fd[0], true) != 0
+
−          || set_nonblocking_flag (fd[1], true) != 0)
+
−        goto fail;
+
−    }
+
−# else
+
−  {
+
−    verify (O_NONBLOCK == 0);
+
−  }
+
−# endif
+
−
+
−  return 0;
+
−
+
−#else
+
−/* Unix API.  */
+
−
+
−  if (pipe (fd) < 0)
+
−    return -1;
+
−
+
−  /* POSIX <http://www.opengroup.org/onlinepubs/9699919799/functions/pipe.html>
+
−     says that initially, the O_NONBLOCK and FD_CLOEXEC flags are cleared on
+
−     both fd[0] and fd[1].  */
+
−
+
−  /* O_NONBLOCK handling.
+
−     On Unix platforms, O_NONBLOCK is defined by the system.  Use fcntl().  */
+
−  if (flags & O_NONBLOCK)
+
−    {
+
−      int fcntl_flags;
+
−
+
−      if ((fcntl_flags = fcntl (fd[1], F_GETFL, 0)) < 0
+
−          || fcntl (fd[1], F_SETFL, fcntl_flags | O_NONBLOCK) == -1
+
−          || (fcntl_flags = fcntl (fd[0], F_GETFL, 0)) < 0
+
−          || fcntl (fd[0], F_SETFL, fcntl_flags | O_NONBLOCK) == -1)
+
−        goto fail;
+
−    }
+
−
+
−  if (flags & O_CLOEXEC)
+
−    {
+
−      int fcntl_flags;
+
−
+
−      if ((fcntl_flags = fcntl (fd[1], F_GETFD, 0)) < 0
+
−          || fcntl (fd[1], F_SETFD, fcntl_flags | FD_CLOEXEC) == -1
+
−          || (fcntl_flags = fcntl (fd[0], F_GETFD, 0)) < 0
+
−          || fcntl (fd[0], F_SETFD, fcntl_flags | FD_CLOEXEC) == -1)
+
−        goto fail;
+
−    }
+
−
+
−# if O_BINARY
+
−  if (flags & O_BINARY)
+
−    {
+
−      setmode (fd[1], O_BINARY);
+
−      setmode (fd[0], O_BINARY);
+
−    }
+
−  else if (flags & O_TEXT)
+
−    {
+
−      setmode (fd[1], O_TEXT);
+
−      setmode (fd[0], O_TEXT);
+
−    }
+
−# endif
+
−
+
−  return 0;
+
−
+
−#endif
+
−
+
−#if GNULIB_defined_O_NONBLOCK || \
+
−  !((defined _WIN32 || defined __WIN32__) && ! defined __CYGWIN__)
+
− fail:
+
−  {
+
−    int saved_errno = errno;
+
−    close (fd[0]);
+
−    close (fd[1]);
+
−    fd[0] = tmp[0];
+
−    fd[1] = tmp[1];
+
−    errno = saved_errno;
+
−    return -1;
+
−  }
+
−#endif
+
−}