linux-user: pass sockaddr from host to target

Signed-off-by: Jing Huang <jing.huang.pku@gmail.com>
Reviewed-by: Peter Maydell <peter.maydell@linaro.org>
Signed-off-by: Peter Maydell <peter.maydell@linaro.org>

linux-user/syscall.c

@@ -1268,7 +1268,6 @@ static inline abi_long host_to_target_sockaddr(abi_ulong target_addr,
     return 0;
 }
 
-/* ??? Should this also swap msgh->name?  */
 static inline abi_long target_to_host_cmsg(struct msghdr *msgh,
                                            struct target_msghdr *target_msgh)
 {
@@ -1325,7 +1324,6 @@ static inline abi_long target_to_host_cmsg(struct msghdr *msgh,
     return 0;
 }
 
-/* ??? Should this also swap msgh->name?  */
 static inline abi_long host_to_target_cmsg(struct target_msghdr *target_msgh,
                                            struct msghdr *msgh)
 {
@@ -1885,10 +1883,22 @@ static abi_long do_sendrecvmsg(int fd, abi_ulong target_msg,
         if (!is_error(ret)) {
             len = ret;
             ret = host_to_target_cmsg(msgp, &msg);
-            if (!is_error(ret))
+            if (!is_error(ret)) {
+                msgp->msg_namelen = tswap32(msg.msg_namelen);
+                if (msg.msg_name != NULL) {
+                    ret = host_to_target_sockaddr(tswapal(msgp->msg_name),
+                                    msg.msg_name, msg.msg_namelen);
+                    if (ret) {
+                        goto out;
+                    }
+                }
+
                 ret = len;
+            }
         }
     }
+
+out:
     unlock_iovec(vec, target_vec, count, !send);
     unlock_user_struct(msgp, target_msg, send ? 0 : 1);
     return ret;