diff --git a/platform/src/linux/mod.rs b/platform/src/linux/mod.rs
index d146fe10952ea8cf92917c33520dcd979e0f4684..20c1d59355a662b5f586413a29aca662e01ee02b 100644
--- a/platform/src/linux/mod.rs
+++ b/platform/src/linux/mod.rs
@@ -14,7 +14,7 @@ pub fn chdir(path: *const c_char) -> c_int {
     }
 }
 
-pub fn chown(path: *const c_char, owner: usize, group: usize) -> c_int {
+pub fn chown(path: *const c_char, owner: uid_t, group: gid_t) -> c_int {
     unsafe {
         syscall!(CHOWN, owner as u32, group as u32) as c_int
     }
@@ -45,6 +45,12 @@ pub fn exit(status: c_int) -> ! {
     loop {}
 }
 
+pub fn fchown(fildes: c_int, owner: uid_t, group: gid_t) -> c_int {
+    unsafe {
+        syscall!(FCHOWN, owner, group) as c_int
+    }
+}
+
 #[cfg(target_arch = "x86_64")]
 pub fn open(path: *const c_char, oflag: c_int, mode: mode_t) -> c_int {
     unsafe {
diff --git a/platform/src/redox/mod.rs b/platform/src/redox/mod.rs
index c0cc9b06f766db7fc5da21a3ec57f604a1953efd..02755a3c9edd692b456c949c7945e62e899be285 100644
--- a/platform/src/redox/mod.rs
+++ b/platform/src/redox/mod.rs
@@ -14,9 +14,9 @@ pub fn chdir(path: *const c_char) -> c_int {
     syscall::chdir(cstr_to_slice(path))? as c_int
 }
 
-pub fn chown(path: *const c_char, owner: usize, group: usize) -> c_int {
+pub fn chown(path: *const c_char, owner: uid_t, group: gid_t) -> c_int {
     let fd = syscall::open(cstr_to_slice(path));
-    syscall::fchown(fd, owner as u32, group as u32)? as c_int
+    syscall::fchown(fd, owner, group)? as c_int
 
 pub fn close(fd: c_int) -> c_int {
     syscall::close(fd as usize);
@@ -36,6 +36,10 @@ pub fn exit(status: c_int) -> ! {
     loop {}
 }
 
+pub fn fchown(fd: c_int, owner: uid_t, group: gid_t) -> c_int {
+    syscall::fchown(owner, group)? as c_int
+}
+
 pub fn open(path: *const c_char, oflag: c_int, mode: mode_t) -> c_int {
     let path = unsafe { c_str(path) };
     syscall::open(path, (oflag as usize) | (mode as usize)).unwrap() as c_int
diff --git a/src/unistd/src/lib.rs b/src/unistd/src/lib.rs
index 485a38debb797dd643b2d83d51183f501139db0c..2b7de078b47104805673391fc16e32ec20209207 100644
--- a/src/unistd/src/lib.rs
+++ b/src/unistd/src/lib.rs
@@ -131,7 +131,7 @@ pub extern "C" fn execvp(file: *const c_char, argv: *const *mut c_char) -> c_int
 
 #[no_mangle]
 pub extern "C" fn fchown(fildes: c_int, owner: uid_t, group: gid_t) -> c_int {
-    unimplemented!();
+    platform::fchown(fildes, owner, group)
 }
 
 #[no_mangle]