cmsg: fix problems

Author: geofft

src/sys/socket/mod.rs

@@ -120,7 +120,7 @@ struct cmsghdr {
     pub cmsg_len: type_of_cmsg_len,
     pub cmsg_level: c_int,
     pub cmsg_type: c_int,
-    cmsg_data: [size_t; 0]
+    cmsg_data: [type_of_cmsg_len; 0]
 }
 
 /// A structure used to make room in a cmsghdr passed to recvmsg. The
@@ -284,8 +284,10 @@ impl<'a> ControlMessage<'a> {
 ///
 /// Allocates if cmsgs is nonempty.
 pub fn sendmsg<'a>(fd: RawFd, iov: &[IoVec<&'a [u8]>], cmsgs: &[ControlMessage<'a>], flags: SockMessageFlags, addr: Option<&'a SockAddr>) -> Result<usize> {
+    let mut len = 0;
     let mut capacity = 0;
     for cmsg in cmsgs {
+        len += cmsg.len();
         capacity += cmsg.space();
     }
     // Alignment hackery. Note that capacity is guaranteed to be a
@@ -315,7 +317,7 @@ pub fn sendmsg<'a>(fd: RawFd, iov: &[IoVec<&'a [u8]>], cmsgs: &[ControlMessage<'
         msg_iov: iov.as_ptr(),
         msg_iovlen: iov.len() as size_t,
         msg_control: cmsg_buffer.as_ptr() as *const c_void,
-        msg_controllen: cmsg_buffer.len() as size_t,
+        msg_controllen: len as size_t,
         msg_flags: 0,
     };
     let ret = unsafe { ffi::sendmsg(fd, &mhdr, flags) };