1 /* Create a pipe, with specific opening flags.
2 Copyright (C) 2009-2011 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, write to the Free Software Foundation,
16 Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA. */
26 #include "binary-io.h"
29 #if GNULIB_defined_O_NONBLOCK
30 # include "nonblocking.h"
33 #if (defined _WIN32 || defined __WIN32__) && ! defined __CYGWIN__
34 /* Native Woe32 API. */
41 pipe2 (int fd[2], int flags)
43 /* Mingw _pipe() corrupts fd on failure; also, if we succeed at
44 creating the pipe but later fail at changing fcntl, we want
45 to leave fd unchanged: http://austingroupbugs.net/view.php?id=467 */
52 /* Try the system call first, if it exists. (We may be running with a glibc
53 that has the function but with an older kernel that lacks it.) */
55 /* Cache the information whether the system call really exists. */
56 static int have_pipe2_really; /* 0 = unknown, 1 = yes, -1 = no */
57 if (have_pipe2_really >= 0)
59 int result = pipe2 (fd, flags);
60 if (!(result < 0 && errno == ENOSYS))
62 have_pipe2_really = 1;
65 have_pipe2_really = -1;
70 /* Check the supported flags. */
71 if ((flags & ~(O_CLOEXEC | O_NONBLOCK | O_BINARY | O_TEXT)) != 0)
77 #if (defined _WIN32 || defined __WIN32__) && ! defined __CYGWIN__
78 /* Native Woe32 API. */
80 if (_pipe (fd, 4096, flags & ~O_NONBLOCK) < 0)
87 /* O_NONBLOCK handling.
88 On native Windows platforms, O_NONBLOCK is defined by gnulib. Use the
89 functions defined by the gnulib module 'nonblocking'. */
90 # if GNULIB_defined_O_NONBLOCK
91 if (flags & O_NONBLOCK)
93 if (set_nonblocking_flag (fd[0], true) != 0
94 || set_nonblocking_flag (fd[1], true) != 0)
98 verify (O_NONBLOCK == 0);
109 /* POSIX <http://www.opengroup.org/onlinepubs/9699919799/functions/pipe.html>
110 says that initially, the O_NONBLOCK and FD_CLOEXEC flags are cleared on
111 both fd[0] and fd[1]. */
113 /* O_NONBLOCK handling.
114 On Unix platforms, O_NONBLOCK is defined by the system. Use fcntl(). */
115 if (flags & O_NONBLOCK)
119 if ((fcntl_flags = fcntl (fd[1], F_GETFL, 0)) < 0
120 || fcntl (fd[1], F_SETFL, fcntl_flags | O_NONBLOCK) == -1
121 || (fcntl_flags = fcntl (fd[0], F_GETFL, 0)) < 0
122 || fcntl (fd[0], F_SETFL, fcntl_flags | O_NONBLOCK) == -1)
126 if (flags & O_CLOEXEC)
130 if ((fcntl_flags = fcntl (fd[1], F_GETFD, 0)) < 0
131 || fcntl (fd[1], F_SETFD, fcntl_flags | FD_CLOEXEC) == -1
132 || (fcntl_flags = fcntl (fd[0], F_GETFD, 0)) < 0
133 || fcntl (fd[0], F_SETFD, fcntl_flags | FD_CLOEXEC) == -1)
138 if (flags & O_BINARY)
140 setmode (fd[1], O_BINARY);
141 setmode (fd[0], O_BINARY);
143 else if (flags & O_TEXT)
145 setmode (fd[1], O_TEXT);
146 setmode (fd[0], O_TEXT);
156 int saved_errno = errno;