More OSX debugging help

Author: asomers

src/sys/socket/mod.rs

@@ -453,6 +453,7 @@ impl<'a> Iterator for CmsgIterator<'a> {
                 // to valid data returned by recvmsg(2)
                 self.cmsghdr = unsafe {
                     let p = CMSG_NXTHDR(self.mhdr as *const _, hdr as *const _);
+                    println!("Next cmsg @ {:?}", p);
                     p.as_ref()
                 };
                 cm
@@ -594,6 +595,7 @@ impl ControlMessageOwned {
         let p = CMSG_DATA(header);
         let len = header as *const _ as usize + header.cmsg_len as usize
             - p as usize;
+        println!("Decoding cmsg level={} type={}", (*header).cmsg_level, (*header).cmsg_type);
         match ((*header).cmsg_level, (*header).cmsg_type) {
             (libc::SOL_SOCKET, libc::SCM_RIGHTS) => {
                 let n = len / mem::size_of::<RawFd>();
@@ -897,9 +899,12 @@ pub fn recvmsg<'a>(fd: RawFd, iov: &[IoVec<&mut [u8]>],
                 // got control message(s)
                 debug_assert!(!mhdr.msg_control.is_null());
                 debug_assert!(msg_controllen >= mhdr.msg_controllen as usize);
+                let sl = slice::from_raw_parts(msg_control, msg_controllen);
+                println!("msg_controllen={} msg_buffer {:?} @ {:?}",
+                         msg_controllen, sl, msg_control);
                 let hdr = CMSG_FIRSTHDR(&mhdr as *const msghdr);
-                println!("cmsghdr: cmsg_len={}, cmsg_level={}, cmsg_type={}",
-                         (*hdr).cmsg_len, (*hdr).cmsg_level, (*hdr).cmsg_type);
+                println!("cmsghdr: {:?} cmsg_len={}, cmsg_level={}, cmsg_type={}",
+                         hdr, (*hdr).cmsg_len, (*hdr).cmsg_level, (*hdr).cmsg_type);
                 hdr
             } else {
                 ptr::null()