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/* Create a pipe, with specific opening flags.
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Copyright (C) 2009-2012 Free Software Foundation, Inc.
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This program is free software; you can redistribute it and/or modify
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it under the terms of the GNU General Public License as published by
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the Free Software Foundation; either version 3, or (at your option)
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This program is distributed in the hope that it will be useful,
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but WITHOUT ANY WARRANTY; without even the implied warranty of
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MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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GNU General Public License for more details.
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You should have received a copy of the GNU General Public License along
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with this program; if not, see <http://www.gnu.org/licenses/>. */
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#include "binary-io.h"
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#if GNULIB_defined_O_NONBLOCK
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# include "nonblocking.h"
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#if (defined _WIN32 || defined __WIN32__) && ! defined __CYGWIN__
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/* Native Windows API. */
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pipe2 (int fd[2], int flags)
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/* Mingw _pipe() corrupts fd on failure; also, if we succeed at
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creating the pipe but later fail at changing fcntl, we want
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to leave fd unchanged: http://austingroupbugs.net/view.php?id=467 */
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/* Try the system call first, if it exists. (We may be running with a glibc
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that has the function but with an older kernel that lacks it.) */
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/* Cache the information whether the system call really exists. */
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static int have_pipe2_really; /* 0 = unknown, 1 = yes, -1 = no */
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if (have_pipe2_really >= 0)
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int result = pipe2 (fd, flags);
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if (!(result < 0 && errno == ENOSYS))
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have_pipe2_really = 1;
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have_pipe2_really = -1;
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/* Check the supported flags. */
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if ((flags & ~(O_CLOEXEC | O_NONBLOCK | O_BINARY | O_TEXT)) != 0)
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#if (defined _WIN32 || defined __WIN32__) && ! defined __CYGWIN__
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/* Native Windows API. */
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if (_pipe (fd, 4096, flags & ~O_NONBLOCK) < 0)
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/* O_NONBLOCK handling.
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On native Windows platforms, O_NONBLOCK is defined by gnulib. Use the
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functions defined by the gnulib module 'nonblocking'. */
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# if GNULIB_defined_O_NONBLOCK
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if (flags & O_NONBLOCK)
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if (set_nonblocking_flag (fd[0], true) != 0
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|| set_nonblocking_flag (fd[1], true) != 0)
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verify (O_NONBLOCK == 0);
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/* POSIX <http://www.opengroup.org/onlinepubs/9699919799/functions/pipe.html>
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says that initially, the O_NONBLOCK and FD_CLOEXEC flags are cleared on
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both fd[0] and fd[1]. */
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/* O_NONBLOCK handling.
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On Unix platforms, O_NONBLOCK is defined by the system. Use fcntl(). */
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if (flags & O_NONBLOCK)
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if ((fcntl_flags = fcntl (fd[1], F_GETFL, 0)) < 0
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|| fcntl (fd[1], F_SETFL, fcntl_flags | O_NONBLOCK) == -1
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|| (fcntl_flags = fcntl (fd[0], F_GETFL, 0)) < 0
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|| fcntl (fd[0], F_SETFL, fcntl_flags | O_NONBLOCK) == -1)
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if (flags & O_CLOEXEC)
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if ((fcntl_flags = fcntl (fd[1], F_GETFD, 0)) < 0
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|| fcntl (fd[1], F_SETFD, fcntl_flags | FD_CLOEXEC) == -1
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|| (fcntl_flags = fcntl (fd[0], F_GETFD, 0)) < 0
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|| fcntl (fd[0], F_SETFD, fcntl_flags | FD_CLOEXEC) == -1)
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if (flags & O_BINARY)
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setmode (fd[1], O_BINARY);
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setmode (fd[0], O_BINARY);
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else if (flags & O_TEXT)
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setmode (fd[1], O_TEXT);
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setmode (fd[0], O_TEXT);
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#if GNULIB_defined_O_NONBLOCK || \
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!((defined _WIN32 || defined __WIN32__) && ! defined __CYGWIN__)
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int saved_errno = errno;