--- a/src/header/sys_eventfd/mod.rs
+++ b/src/header/sys_eventfd/mod.rs
@@ -5,6 +5,7 @@
 use crate::c_str::{CStr, CString};
 use crate::error::{Errno, ResultExt};
 use crate::header::fcntl::{O_CLOEXEC, O_NONBLOCK, O_RDWR};
+use crate::header::errno::EFAULT;
 use crate::header::errno::EINVAL;
 use crate::platform::{Pal, Sys, types::{c_int, c_uint}};
 
@@ -35,3 +36,24 @@
     }
     Sys::open(CStr::borrow(&cpath), oflag, 0).or_minus_one_errno()
 }
+
+#[unsafe(no_mangle)]
+pub extern "C" fn eventfd_read(fd: c_int, value: *mut eventfd_t) -> c_int {
+    if value.is_null() {
+        return Err::<c_int, _>(Errno(EFAULT)).or_minus_one_errno();
+    }
+    let mut buf = [0u8; 8];
+    match Sys::read(fd, &mut buf) {
+        Ok(8) => { unsafe { *value = u64::from_ne_bytes(buf); } 0 }
+        _ => -1,
+    }
+}
+
+#[unsafe(no_mangle)]
+pub extern "C" fn eventfd_write(fd: c_int, value: eventfd_t) -> c_int {
+    let buf = value.to_ne_bytes();
+    match Sys::write(fd, &buf) {
+        Ok(8) => 0,
+        _ => -1,
+    }
+}