Implement support for getsockopt of peer credentials using the Linux specific SO_PEERCRED

Author: maghoff

src/sys/socket/mod.rs

@@ -6,7 +6,7 @@ use errno::Errno;
 use features;
 use fcntl::{fcntl, FD_CLOEXEC, O_NONBLOCK};
 use fcntl::FcntlArg::{F_SETFD, F_SETFL};
-use libc::{c_void, c_int, socklen_t, size_t};
+use libc::{c_void, c_int, socklen_t, size_t, pid_t, uid_t, gid_t};
 use std::{mem, ptr, slice};
 use std::os::unix::io::RawFd;
 use sys::uio::IoVec;
@@ -581,6 +581,14 @@ pub struct linger {
     pub l_linger: c_int
 }
 
+#[repr(C)]
+#[derive(Clone, Copy, PartialEq, Eq, Debug)]
+pub struct ucred {
+    pid: pid_t,
+    uid: uid_t,
+    gid: gid_t,
+}
+
 /*
  *
  * ===== Socket Options =====

src/sys/socket/sockopt.rs

@@ -137,6 +137,8 @@ sockopt_impl!(Both, Broadcast, consts::SOL_SOCKET, consts::SO_BROADCAST, bool);
 sockopt_impl!(Both, OobInline, consts::SOL_SOCKET, consts::SO_OOBINLINE, bool);
 sockopt_impl!(GetOnly, SocketError, consts::SOL_SOCKET, consts::SO_ERROR, i32);
 sockopt_impl!(Both, KeepAlive, consts::SOL_SOCKET, consts::SO_KEEPALIVE, bool);
+#[cfg(target_os = "linux")]
+sockopt_impl!(GetOnly, PeerCredentials, consts::SOL_SOCKET, consts::SO_PEERCRED, super::ucred);
 #[cfg(any(target_os = "macos",
           target_os = "ios"))]
 sockopt_impl!(Both, TcpKeepAlive, consts::IPPROTO_TCP, consts::TCP_KEEPALIVE, u32);
@@ -300,3 +302,19 @@ impl<'a> Set<'a, u8> for SetU8 {
         mem::size_of::<c_int>() as socklen_t
     }
 }
+
+
+#[cfg(test)]
+mod test {
+    #[cfg(target_os = "linux")]
+    #[test]
+    fn can_get_peercred_on_unix_socket() {
+        use super::super::*;
+
+        let (a, b) = socketpair(AddressFamily::Unix, SockType::Stream, 0, SockFlag::empty()).unwrap();
+        let a_cred = getsockopt(a, super::PeerCredentials).unwrap();
+        let b_cred = getsockopt(b, super::PeerCredentials).unwrap();
+        assert_eq!(a_cred, b_cred);
+        assert!(a_cred.pid != 0);
+    }
+}