diff --git a/src/fcntl/src/lib.rs b/src/fcntl/src/lib.rs
index 72af0c0685..1dca5572c8 100644
--- a/src/fcntl/src/lib.rs
+++ b/src/fcntl/src/lib.rs
@@ -38,7 +38,7 @@ pub extern "C" fn creat(path: *const c_char, mode: mode_t) -> c_int {
 
 #[no_mangle]
 pub extern "C" fn fcntl(fildes: c_int, cmd: c_int, arg: c_int) -> c_int {
-    unimplemented!();
+    platform::fcntl(fildes, cmd, arg)
 }
 
 #[no_mangle]
diff --git a/src/platform/src/linux/mod.rs b/src/platform/src/linux/mod.rs
index ed0c116d45..5f0066c2a4 100644
--- a/src/platform/src/linux/mod.rs
+++ b/src/platform/src/linux/mod.rs
@@ -62,6 +62,10 @@ pub fn fchdir(fildes: c_int) -> c_int {
     e(unsafe { syscall!(FCHDIR, fildes) }) as c_int
 }
 
+pub fn fcntl(fildes: c_int, cmd: c_int, arg: c_int) -> c_int {
+    e(unsafe { syscall!(FCNTL, fildes, cmd, arg) }) as c_int
+}
+
 pub fn fork() -> pid_t {
     e(unsafe { syscall!(FORK) }) as pid_t
 }
diff --git a/src/platform/src/redox/mod.rs b/src/platform/src/redox/mod.rs
index 940098b6bd..edf9ad1724 100644
--- a/src/platform/src/redox/mod.rs
+++ b/src/platform/src/redox/mod.rs
@@ -63,6 +63,10 @@ pub fn fchdir(fd: c_int) -> c_int {
     }
 }
 
+pub fn fcntl(fd: c_int, cmd: c_int, args: c_int) -> c_int {
+    e(syscall::fcntl(fd as usize, cmd as usize, args as usize)) as c_int
+}
+
 pub fn fork() -> pid_t {
     e(unsafe { syscall::clone(0) }) as pid_t
 }