[PATCH] add eventfd syscall wrapper and helper abstractions as in glibc

[Serge Ziryukin <ftrvxmtrx@gmail.com>]

abstractions are:

typedef uint64_t eventfd_t;
int eventfd_read(int fd, eventfd_t *value);
int eventfd_write(int fd, eventfd_t value);

these are trying to hide the details of reading and writing
on an eventfd descriptor.

Signed-off-by: Serge Ziryukin <ftrvxmtrx@gmail.com>
---
 include/sys/eventfd.h     |   25 +++++++++++++++++++++++++
 src/linux/eventfd.c       |    7 +++++++
 src/linux/eventfd_read.c  |    7 +++++++
 src/linux/eventfd_write.c |    7 +++++++
 4 files changed, 46 insertions(+), 0 deletions(-)
 create mode 100644 include/sys/eventfd.h
 create mode 100644 src/linux/eventfd.c
 create mode 100644 src/linux/eventfd_read.c
 create mode 100644 src/linux/eventfd_write.c

diff --git a/include/sys/eventfd.h b/include/sys/eventfd.h
new file mode 100644
index 0000000..13bc9c4
--- /dev/null
+++ b/include/sys/eventfd.h
@@ -0,0 +1,25 @@
+#ifndef _SYS_EVENTFD_H
+#define _SYS_EVENTFD_H
+
+#ifdef __cplusplus
+extern "C" {
+#endif
+
+#include <stdint.h>
+
+typedef uint64_t eventfd_t;
+
+#define EFD_SEMAPHORE 1
+#define EFD_CLOEXEC 02000000
+#define EFD_NONBLOCK 04000
+
+int eventfd(unsigned int, int);
+int eventfd_read(int, eventfd_t *);
+int eventfd_write(int, eventfd_t);
+
+
+#ifdef __cplusplus
+}
+#endif
+
+#endif /* sys/eventfd.h */
diff --git a/src/linux/eventfd.c b/src/linux/eventfd.c
new file mode 100644
index 0000000..2ddfc68
--- /dev/null
+++ b/src/linux/eventfd.c
@@ -0,0 +1,7 @@
+#include <sys/eventfd.h>
+#include "syscall.h"
+
+int eventfd(unsigned int count, int flags)
+{
+	return syscall(SYS_eventfd, count, flags);
+}
diff --git a/src/linux/eventfd_read.c b/src/linux/eventfd_read.c
new file mode 100644
index 0000000..969e661
--- /dev/null
+++ b/src/linux/eventfd_read.c
@@ -0,0 +1,7 @@
+#include <sys/eventfd.h>
+#include <unistd.h>
+
+int eventfd_read(int fd, eventfd_t *value)
+{
+	return (sizeof(*value) == read(fd, value, sizeof(*value))) ? 0 : -1;
+}
diff --git a/src/linux/eventfd_write.c b/src/linux/eventfd_write.c
new file mode 100644
index 0000000..734fa36
--- /dev/null
+++ b/src/linux/eventfd_write.c
@@ -0,0 +1,7 @@
+#include <sys/eventfd.h>
+#include <unistd.h>
+
+int eventfd_write(int fd, eventfd_t value)
+{
+	return (sizeof(value) == write(fd, &value, sizeof(value))) ? 0 : -1;
+}
-- 
1.7.5