linux-user: Use g_try_malloc() in do_msgrcv()

In do_msgrcv() we want to allocate a message buffer, whose size
is passed to us by the guest. That means we could legitimately
fail, so use g_try_malloc() and handle the error case, in the same
way that do_msgsnd() does.
Signed-off-by: NPeter Maydell <peter.maydell@linaro.org>
Signed-off-by: NRiku Voipio <riku.voipio@linaro.org>

linux-user/syscall.c

@@ -3167,7 +3167,11 @@ static inline abi_long do_msgrcv(int msqid, abi_long msgp,
     if (!lock_user_struct(VERIFY_WRITE, target_mb, msgp, 0))
         return -TARGET_EFAULT;
 
-    host_mb = g_malloc(msgsz+sizeof(long));
+    host_mb = g_try_malloc(msgsz + sizeof(long));
+    if (!host_mb) {
+        ret = -TARGET_ENOMEM;
+        goto end;
+    }
     ret = get_errno(msgrcv(msqid, host_mb, msgsz, msgtyp, msgflg));
 
     if (ret > 0) {