Only test addresses of cmsghdrs that are multiples of the size of cmsghdr.

Author: xingxue-ibm

libc-test/tests/cmsg.rs

@@ -6,14 +6,7 @@ mod t {
 
     use std::mem;
 
-    use libc::{
-        self,
-        c_uchar,
-        c_uint,
-        c_void,
-        cmsghdr,
-        msghdr,
-    };
+    use libc::{self, c_uchar, c_uint, c_void, cmsghdr, msghdr};
 
     extern "C" {
         pub fn cmsg_firsthdr(msgh: *const msghdr) -> *mut cmsghdr;
@@ -73,6 +66,14 @@ mod t {
             mhdr.msg_controllen = (160 - trunc) as _;
 
             for cmsg_payload_len in 0..64 {
+                // AIX does not apply any alignment or padding to ancillary
+                // data and CMSG_ALIGN() is a noop. So only test addresses
+                // that are multiples of the size of cmsghdr here.
+                if cfg!(target_os = "aix") && cmsg_payload_len % std::mem::size_of::<cmsghdr>() != 0
+                {
+                    continue;
+                }
+
                 let mut current_cmsghdr_ptr = pcmsghdr;
                 assert!(!current_cmsghdr_ptr.is_null());
                 let mut count = 0;