With the conditional definition of O_CLOEXEC in place in fcntl.h, it's
already possible to implement pipe2.
It does not yet support O_CLOEXEC on systems other than Linux and mingw,
but when O_CLOEXEC will be supported on all platforms, this module does
not need to be changed.
2009-08-22 Bruno Haible <br...@clisp.org>
New module 'pipe2'.
* lib/unistd.in.h (pipe2): New declaration.
* lib/pipe2.c: New file.
* m4/pipe2.m4: New file.
* m4/unistd_h.m4 (gl_UNISTD_H_DEFAULTS): Initialize GNULIB_PIPE2 and
HAVE_PIPE2.
* modules/unistd (Makefile.am): Substitute GNULIB_PIPE2 and HAVE_PIPE2.
* modules/pipe2: New file.
* doc/glibc-functions/pipe2.texi: Mention the new module.
================================= lib/pipe2.c =================================
/* Create a pipe, with specific opening flags.
Copyright (C) 2009 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, write to the Free Software Foundation,
Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA. */
#include <config.h>
/* Specification. */
#include <unistd.h>
#include <errno.h>
#include <fcntl.h>
#if (defined _WIN32 || defined __WIN32__) && ! defined __CYGWIN__
/* Native Woe32 API. */
# include <io.h>
int
pipe2 (int fd[2], int flags)
{
/* Check the supported flags. */
if ((flags & ~(O_CLOEXEC | O_BINARY | O_TEXT)) != 0)
{
errno = EINVAL;
return -1;
}
return _pipe (fd, 4096, flags);
}
#else
/* Unix API. */
# ifndef O_CLOEXEC
# define O_CLOEXEC 0
# endif
int
pipe2 (int fd[2], int flags)
{
/* Check the supported flags. */
if ((flags & ~(O_CLOEXEC | O_NONBLOCK)) != 0)
{
errno = EINVAL;
return -1;
}
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] amd fd[1]. */
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) < 0
|| (fcntl_flags = fcntl (fd[0], F_GETFL, 0)) < 0
|| fcntl (fd[0], F_SETFL, fcntl_flags | O_NONBLOCK) < 0)
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) < 0
|| (fcntl_flags = fcntl (fd[0], F_GETFD, 0)) < 0
|| fcntl (fd[0], F_SETFD, fcntl_flags | FD_CLOEXEC) < 0)
goto fail;
}
return 0;
fail:
{
int saved_errno = errno;
close (fd[0]);
close (fd[1]);
errno = saved_errno;
return -1;
}
}
#endif
================================= m4/pipe2.m4 =================================
# pipe2.m4 serial 1
dnl Copyright (C) 2009 Free Software Foundation, Inc.
dnl This file is free software; the Free Software Foundation
dnl gives unlimited permission to copy and/or distribute it,
dnl with or without modifications, as long as this notice is preserved.
AC_DEFUN([gl_FUNC_PIPE2],
[
AC_REQUIRE([gl_UNISTD_H_DEFAULTS])
dnl Persuade glibc <unistd.h> to declare pipe2().
AC_REQUIRE([AC_USE_SYSTEM_EXTENSIONS])
AC_CHECK_FUNCS_ONCE([pipe2])
if test $ac_cv_func_pipe2 != yes; then
HAVE_PIPE2=0
AC_LIBOBJ([pipe2])
fi
])
================================ modules/pipe2 ================================
Description:
pipe2() function: create a pipe, with specific opening flags.
Files:
lib/pipe2.c
m4/pipe2.m4
Depends-on:
unistd
fcntl
binary-io
configure.ac:
gl_FUNC_PIPE2
gl_UNISTD_MODULE_INDICATOR([pipe2])
Makefile.am:
Include:
<unistd.h>
License:
GPL
Maintainer:
Bruno Haible, Eric Blake
===============================================================================
--- doc/glibc-functions/pipe2.texi.orig 2009-08-22 18:42:44.000000000 +0200
+++ doc/glibc-functions/pipe2.texi 2009-08-22 16:23:54.000000000 +0200
@@ -2,15 +2,15 @@
@subsection @code{pipe2}
@findex pipe2
-Gnulib module: ---
+Gnulib module: pipe2
Portability problems fixed by Gnulib:
@itemize
+...@item
+This function is missing on all non-glibc platforms:
+MacOS X 10.3, FreeBSD 6.0, NetBSD 3.0, OpenBSD 3.8, AIX 5.1, HP-UX 11, IRIX
6.5, OSF/1 5.1, Solaris 10, Cygwin, mingw, Interix 3.5, BeOS.
@end itemize
Portability problems not fixed by Gnulib:
@itemize
-...@item
-This function is missing on all non-glibc platforms:
-MacOS X 10.3, FreeBSD 6.0, NetBSD 3.0, OpenBSD 3.8, AIX 5.1, HP-UX 11, IRIX
6.5, OSF/1 5.1, Solaris 10, Cygwin, mingw, Interix 3.5, BeOS.
@end itemize
--- lib/unistd.in.h.orig 2009-08-22 18:42:44.000000000 +0200
+++ lib/unistd.in.h 2009-08-22 16:23:29.000000000 +0200
@@ -531,6 +531,25 @@
#endif
+#if @GNULIB_PIPE2@
+/* Create a pipe, applying the given flags when opening the read-end of the
+ pipe and the write-end of the pipe.
+ The flags are a bitmask, possibly including O_CLOEXEC (defined in <fcntl.h>)
+ and O_TEXT, O_BINARY (defined in "binary-io.h").
+ Store the read-end as fd[0] and the write-end as fd[1].
+ Return 0 upon success, or -1 with errno set upon failure. */
+# if !...@have_pipe2@
+extern int pipe2 (int fd[2], int flags);
+# endif
+#elif defined GNULIB_POSIXCHECK
+# undef pipe2
+# define pipe2(f,o) \
+ (GL_LINK_WARNING ("pipe2 is unportable - " \
+ "use gnulib module pipe2 for portability"), \
+ pipe2 (f, o))
+#endif
+
+
#if @GNULIB_READLINK@
/* Read the contents of the symbolic link FILE and place the first BUFSIZE
bytes of it into BUF. Return the number of bytes placed into BUF if
--- m4/unistd_h.m4.orig 2009-08-22 18:42:44.000000000 +0200
+++ m4/unistd_h.m4 2009-08-22 15:42:00.000000000 +0200
@@ -1,4 +1,4 @@
-# unistd_h.m4 serial 19
+# unistd_h.m4 serial 20
dnl Copyright (C) 2006-2009 Free Software Foundation, Inc.
dnl This file is free software; the Free Software Foundation
dnl gives unlimited permission to copy and/or distribute it,
@@ -50,6 +50,7 @@
GNULIB_LCHOWN=0; AC_SUBST([GNULIB_LCHOWN])
GNULIB_LINK=0; AC_SUBST([GNULIB_LINK])
GNULIB_LSEEK=0; AC_SUBST([GNULIB_LSEEK])
+ GNULIB_PIPE2=0; AC_SUBST([GNULIB_PIPE2])
GNULIB_READLINK=0; AC_SUBST([GNULIB_READLINK])
GNULIB_SLEEP=0; AC_SUBST([GNULIB_SLEEP])
GNULIB_UNISTD_H_GETOPT=0; AC_SUBST([GNULIB_UNISTD_H_GETOPT])
@@ -66,6 +67,7 @@
HAVE_GETPAGESIZE=1; AC_SUBST([HAVE_GETPAGESIZE])
HAVE_GETUSERSHELL=1; AC_SUBST([HAVE_GETUSERSHELL])
HAVE_LINK=1; AC_SUBST([HAVE_LINK])
+ HAVE_PIPE2=1; AC_SUBST([HAVE_PIPE2])
HAVE_READLINK=1; AC_SUBST([HAVE_READLINK])
HAVE_SLEEP=1; AC_SUBST([HAVE_SLEEP])
HAVE_DECL_ENVIRON=1; AC_SUBST([HAVE_DECL_ENVIRON])
--- modules/unistd.orig 2009-08-22 18:42:44.000000000 +0200
+++ modules/unistd 2009-08-22 15:42:41.000000000 +0200
@@ -43,6 +43,7 @@
-e 's|@''GNULIB_LCHOWN''@|$(GNULIB_LCHOWN)|g' \
-e 's|@''GNULIB_LINK''@|$(GNULIB_LINK)|g' \
-e 's|@''GNULIB_LSEEK''@|$(GNULIB_LSEEK)|g' \
+ -e 's|@''GNULIB_PIPE2''@|$(GNULIB_PIPE2)|g' \
-e 's|@''GNULIB_READLINK''@|$(GNULIB_READLINK)|g' \
-e 's|@''GNULIB_SLEEP''@|$(GNULIB_SLEEP)|g' \
-e 's|@''GNULIB_UNISTD_H_GETOPT''@|$(GNULIB_UNISTD_H_GETOPT)|g' \
@@ -58,6 +59,7 @@
-e 's|@''HAVE_GETPAGESIZE''@|$(HAVE_GETPAGESIZE)|g' \
-e 's|@''HAVE_GETUSERSHELL''@|$(HAVE_GETUSERSHELL)|g' \
-e 's|@''HAVE_LINK''@|$(HAVE_LINK)|g' \
+ -e 's|@''HAVE_PIPE2''@|$(HAVE_PIPE2)|g' \
-e 's|@''HAVE_READLINK''@|$(HAVE_READLINK)|g' \
-e 's|@''HAVE_SLEEP''@|$(HAVE_SLEEP)|g' \
-e 's|@''HAVE_DECL_ENVIRON''@|$(HAVE_DECL_ENVIRON)|g' \
