1 /* Create a pipe, with specific opening flags.
2 Copyright (C) 2009-2013 Free Software Foundation, Inc.
4 This program is free software; you can redistribute it and/or modify
5 it under the terms of the GNU General Public License as published by
6 the Free Software Foundation; either version 2, or (at your option)
9 This program 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
12 GNU General Public License for more details.
14 You should have received a copy of the GNU General Public License along
15 with this program; if not, see <http://www.gnu.org/licenses/>. */
26 # include "binary-io.h"
31 #if GNULIB_defined_O_NONBLOCK
32 # include "nonblocking.h"
35 #if (defined _WIN32 || defined __WIN32__) && ! defined __CYGWIN__
36 /* Native Windows API. */
43 pipe2 (int fd[2], int flags)
45 /* Mingw _pipe() corrupts fd on failure; also, if we succeed at
46 creating the pipe but later fail at changing fcntl, we want
47 to leave fd unchanged: http://austingroupbugs.net/view.php?id=467 */
54 /* Try the system call first, if it exists. (We may be running with a glibc
55 that has the function but with an older kernel that lacks it.) */
57 /* Cache the information whether the system call really exists. */
58 static int have_pipe2_really; /* 0 = unknown, 1 = yes, -1 = no */
59 if (have_pipe2_really >= 0)
61 int result = pipe2 (fd, flags);
62 if (!(result < 0 && errno == ENOSYS))
64 have_pipe2_really = 1;
67 have_pipe2_really = -1;
72 /* Check the supported flags. */
73 if ((flags & ~(O_CLOEXEC | O_NONBLOCK | O_BINARY | O_TEXT)) != 0)
79 #if (defined _WIN32 || defined __WIN32__) && ! defined __CYGWIN__
80 /* Native Windows API. */
82 if (_pipe (fd, 4096, flags & ~O_NONBLOCK) < 0)
89 /* O_NONBLOCK handling.
90 On native Windows platforms, O_NONBLOCK is defined by gnulib. Use the
91 functions defined by the gnulib module 'nonblocking'. */
92 # if GNULIB_defined_O_NONBLOCK
93 if (flags & O_NONBLOCK)
95 if (set_nonblocking_flag (fd[0], true) != 0
96 || set_nonblocking_flag (fd[1], true) != 0)
101 verify (O_NONBLOCK == 0);
113 /* POSIX <http://www.opengroup.org/onlinepubs/9699919799/functions/pipe.html>
114 says that initially, the O_NONBLOCK and FD_CLOEXEC flags are cleared on
115 both fd[0] and fd[1]. */
117 /* O_NONBLOCK handling.
118 On Unix platforms, O_NONBLOCK is defined by the system. Use fcntl(). */
119 if (flags & O_NONBLOCK)
123 if ((fcntl_flags = fcntl (fd[1], F_GETFL, 0)) < 0
124 || fcntl (fd[1], F_SETFL, fcntl_flags | O_NONBLOCK) == -1
125 || (fcntl_flags = fcntl (fd[0], F_GETFL, 0)) < 0
126 || fcntl (fd[0], F_SETFL, fcntl_flags | O_NONBLOCK) == -1)
130 if (flags & O_CLOEXEC)
134 if ((fcntl_flags = fcntl (fd[1], F_GETFD, 0)) < 0
135 || fcntl (fd[1], F_SETFD, fcntl_flags | FD_CLOEXEC) == -1
136 || (fcntl_flags = fcntl (fd[0], F_GETFD, 0)) < 0
137 || fcntl (fd[0], F_SETFD, fcntl_flags | FD_CLOEXEC) == -1)
142 if (flags & O_BINARY)
144 setmode (fd[1], O_BINARY);
145 setmode (fd[0], O_BINARY);
147 else if (flags & O_TEXT)
149 setmode (fd[1], O_TEXT);
150 setmode (fd[0], O_TEXT);
158 #if GNULIB_defined_O_NONBLOCK || \
159 !((defined _WIN32 || defined __WIN32__) && ! defined __CYGWIN__)
162 int saved_errno = errno;