fdtrack: add wrapper for eventfd.

Bug: https://issuetracker.google.com/154450436
Test: bionic-unit-tests
Change-Id: I59013f0c4da0debbcc50269c64ae9db0cdc4eaa0

libc/Android.bp

@@ -1022,8 +1022,7 @@ cc_library_static {
         "bionic/dup.cpp",
         "bionic/environ.cpp",
         "bionic/error.cpp",
-        "bionic/eventfd_read.cpp",
-        "bionic/eventfd_write.cpp",
+        "bionic/eventfd.cpp",
         "bionic/exec.cpp",
         "bionic/faccessat.cpp",
         "bionic/fchmod.cpp",

libc/SYSCALLS.TXT

@@ -312,7 +312,7 @@ int __epoll_create1:epoll_create1(int)  all
 int epoll_ctl(int, int op, int, struct epoll_event*)  all
 int __epoll_pwait:epoll_pwait(int, struct epoll_event*, int, int, const sigset64_t*, size_t)  all
 
-int eventfd:eventfd2(unsigned int, int)  all
+int __eventfd:eventfd2(unsigned int, int)  all
 
 void _exit|_Exit:exit_group(int)  all
 void __exit:exit(int)  all

libc/bionic/eventfd.cpp

@@ -29,6 +29,18 @@
 #include <sys/eventfd.h>
 #include <unistd.h>
 
+#include "private/bionic_fdtrack.h"
+
+extern "C" int __eventfd(unsigned int initval, int flags);
+
+int eventfd(unsigned int initval, int flags) {
+  return FDTRACK_CREATE(__eventfd(initval, flags));
+}
+
 int eventfd_read(int fd, eventfd_t* value) {
   return (read(fd, value, sizeof(*value)) == sizeof(*value)) ? 0 : -1;
 }
+
+int eventfd_write(int fd, eventfd_t value) {
+  return (write(fd, &value, sizeof(value)) == sizeof(value)) ? 0 : -1;
+}

libc/bionic/eventfd_write.cpp

@@ -29,6 +29,3 @@
 #include <sys/eventfd.h>
 #include <unistd.h>
 
-int eventfd_write(int fd, eventfd_t value) {
-  return (write(fd, &value, sizeof(value)) == sizeof(value)) ? 0 : -1;
-}

tests/fdtrack_test.cpp

@@ -23,6 +23,7 @@
 #include <netinet/in.h>
 #include <stdlib.h>
 #include <sys/epoll.h>
+#include <sys/eventfd.h>
 #include <sys/types.h>
 #include <unistd.h>
 
@@ -205,6 +206,8 @@ FDTRACK_TEST(pipe2, ({
 FDTRACK_TEST(epoll_create, epoll_create(1));
 FDTRACK_TEST(epoll_create1, epoll_create1(0));
 
+FDTRACK_TEST(eventfd, eventfd(0, 0));
+
 #if 0
 // Why is this generating an extra socket/close event?
 FDTRACK_TEST(accept, ({