Add eventfd support.

Hello,

I whould like to share this simple patch that add the eventfd call to
uClibc. Please review so it can be accepted to be merged.

Jean-Christian

Signed-off-by: Jean-Christian de Rivaz <jc@eclis.ch>
Signed-off-by: Carmelo Amoroso <carmelo.amoroso@st.com>

libc/sysdeps/linux/common/Makefile.in

@@ -24,7 +24,8 @@ CSRC-$(UCLIBC_LINUX_SPECIFIC) += capget.c capset.c inotify.c ioperm.c iopl.c \
 	remap_file_pages.c sched_getaffinity.c sched_setaffinity.c \
 	sendfile64.c sendfile.c setfsgid.c setfsuid.c setresuid.c \
 	splice.c vmsplice.c tee.c signalfd.c swapoff.c swapon.c \
-	sync_file_range.c sysctl.c sysinfo.c timerfd.c uselib.c vhangup.c
+	sync_file_range.c sysctl.c sysinfo.c eventfd.c timerfd.c uselib.c \
+	vhangup.c
 # NPTL needs these internally: madvise.c
 CSRC-$(findstring y,$(UCLIBC_LINUX_SPECIFIC)$(UCLIBC_HAS_THREADS_NATIVE)) += madvise.c
 ifeq ($(UCLIBC_HAS_THREADS_NATIVE),y)

libc/sysdeps/linux/common/eventfd.c

@@ -0,0 +1,18 @@
+/* vi: set sw=4 ts=4: */
+/*
+ * eventfd() for uClibc
+ *
+ * Copyright (C) 2011 Jean-Christian de Rivaz <jc@eclis.ch>
+ *
+ * Licensed under the LGPL v2.1, see the file COPYING.LIB in this tarball.
+ */
+
+#include <sys/syscall.h>
+#include <sys/eventfd.h>
+
+/*
+ * eventfd()
+ */
+#ifdef __NR_eventfd
+_syscall2(int, eventfd, int, count, int, flags)
+#endif

libc/sysdeps/linux/common/sys/eventfd.h

@@ -0,0 +1,48 @@
+/* Copyright (C) 2007, 2008, 2009 Free Software Foundation, Inc.
+   This file is part of the GNU C Library.
+
+   The GNU C Library is free software; you can redistribute it and/or
+   modify it under the terms of the GNU Lesser General Public
+   License as published by the Free Software Foundation; either
+   version 2.1 of the License, or (at your option) any later version.
+
+   The GNU C Library 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
+   Lesser General Public License for more details.
+
+   You should have received a copy of the GNU Lesser General Public
+   License along with the GNU C Library; if not, write to the Free
+   Software Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA
+   02111-1307 USA.  */
+
+#ifndef	_SYS_EVENTFD_H
+#define	_SYS_EVENTFD_H	1
+
+#include <stdint.h>
+
+
+/* Type for event counter.  */
+typedef uint64_t eventfd_t;
+
+/* Flags for signalfd.  */
+enum
+  {
+    EFD_SEMAPHORE = 1,
+#define EFD_SEMAPHORE EFD_SEMAPHORE
+    EFD_CLOEXEC = 02000000,
+#define EFD_CLOEXEC EFD_CLOEXEC
+    EFD_NONBLOCK = 04000
+#define EFD_NONBLOCK EFD_NONBLOCK
+  };
+
+
+__BEGIN_DECLS
+
+/* Return file descriptor for generic event channel.  Set initial
+   value to COUNT.  */
+extern int eventfd (int __count, int __flags) __THROW;
+
+__END_DECLS
+
+#endif /* sys/eventfd.h */