SonarCloud: fix some easy codesmells

src/lib/ares_dns_write.c

@@ -242,7 +242,7 @@ static ares_status_t ares_dns_write_rr_binstrs(ares__buf_t         *buf,
 
     /* String */
     if (len) {
-      status = ares__buf_append(buf, (const unsigned char *)ptr, len);
+      status = ares__buf_append(buf, ptr, len);
       if (status != ARES_SUCCESS) {
         return status;
       }

src/lib/ares_fds.c

@@ -48,16 +48,17 @@ int ares_fds(ares_channel_t *channel, fd_set *read_fds, fd_set *write_fds)
          node = ares__llist_node_next(node)) {
       const struct server_connection *conn = ares__llist_node_val(node);
 
-      /* We only need to register interest in UDP sockets if we have
-       * outstanding queries.
-       */
-      if (active_queries || conn->is_tcp) {
+      if (!active_queries && !conn->is_tcp)
+        continue;
+
+      /* Always wait on read */
       FD_SET(conn->fd, read_fds);
+
       if (conn->fd >= nfds) {
         nfds = conn->fd + 1;
       }
-      }
 
+      /* TCP only wait on write if we have buffered data */
       if (conn->is_tcp && ares__buf_len(server->tcp_send)) {
         FD_SET(conn->fd, write_fds);
       }

src/lib/ares_process.c

@@ -675,10 +675,8 @@ static ares_status_t process_answer(ares_channel_t      *channel,
    */
   if (ares_dns_record_get_flags(rdnsrec) & ARES_FLAG_TC && !tcp &&
       !(channel->flags & ARES_FLAG_IGNTC)) {
-    if (!query->using_tcp) {
     query->using_tcp = ARES_TRUE;
     ares__send_query(query, now);
-    }
     status = ARES_SUCCESS; /* Switched to TCP is ok */
     goto cleanup;
   }
@@ -739,8 +737,9 @@ static void handle_conn_error(struct server_connection *conn,
 
 ares_status_t ares__requeue_query(struct query *query, struct timeval *now)
 {
-  ares_channel_t *channel = query->channel;
-  size_t max_tries        = ares__slist_len(channel->servers) * channel->tries;
+  const ares_channel_t *channel   = query->channel;
+  size_t                max_tries = ares__slist_len(channel->servers) *
+                                    channel->tries;
 
   query->try_count++;
 
@@ -797,6 +796,39 @@ static ares_status_t ares__append_tcpbuf(struct server_state *server,
   return ares__buf_append(server->tcp_send, query->qbuf, query->qlen);
 }
 
+
+static size_t ares__retry_penalty(struct query *query)
+{
+  const ares_channel_t *channel  = query->channel;
+  size_t                timeplus = channel->timeout;
+  size_t                shift;
+
+  /* For each trip through the entire server list, double the channel's
+   * assigned timeout, avoiding overflow.  If channel->timeout is negative,
+   * leave it as-is, even though that should be impossible here.
+   */
+
+  /* How many times do we want to double it?  Presume sane values here. */
+  shift = query->try_count / ares__slist_len(channel->servers);
+
+  /* Is there enough room to shift timeplus left that many times?
+   *
+   * To find out, confirm that all of the bits we'll shift away are zero.
+   * Stop considering a shift if we get to the point where we could shift
+   * a 1 into the sign bit (i.e. when shift is within two of the bit
+   * count).
+   *
+   * This has the side benefit of leaving negative numbers unchanged.
+   */
+  if (shift <= (sizeof(int) * CHAR_BIT - 1) &&
+      (timeplus >> (sizeof(int) * CHAR_BIT - 1 - shift)) == 0) {
+    timeplus <<= shift;
+  }
+
+  return timeplus;
+}
+
+
 ares_status_t ares__send_query(struct query *query, struct timeval *now)
 {
   ares_channel_t           *channel = query->channel;
@@ -920,29 +952,7 @@ ares_status_t ares__send_query(struct query *query, struct timeval *now)
     }
   }
 
-  /* For each trip through the entire server list, double the channel's
-   * assigned timeout, avoiding overflow.  If channel->timeout is negative,
-   * leave it as-is, even though that should be impossible here.
-   */
-  timeplus = channel->timeout;
-  {
-    /* How many times do we want to double it?  Presume sane values here. */
-    const size_t shift = query->try_count / ares__slist_len(channel->servers);
-
-    /* Is there enough room to shift timeplus left that many times?
-     *
-     * To find out, confirm that all of the bits we'll shift away are zero.
-     * Stop considering a shift if we get to the point where we could shift
-     * a 1 into the sign bit (i.e. when shift is within two of the bit
-     * count).
-     *
-     * This has the side benefit of leaving negative numbers unchanged.
-     */
-    if (shift <= (sizeof(int) * CHAR_BIT - 1) &&
-        (timeplus >> (sizeof(int) * CHAR_BIT - 1 - shift)) == 0) {
-      timeplus <<= shift;
-    }
-  }
+  timeplus = ares__retry_penalty(query);
 
   /* Keep track of queries bucketed by timeout, so we can process
    * timeout events quickly.

src/lib/ares_update_servers.c

@@ -382,7 +382,7 @@ static ares__slist_node_t *ares__server_find(ares_channel_t       *channel,
   return NULL;
 }
 
-static ares_bool_t ares__server_isdup(ares_channel_t     *channel,
+static ares_bool_t ares__server_isdup(const ares_channel_t *channel,
                                       ares__llist_node_t   *s)
 {
   /* Scan backwards to see if this is a duplicate */
@@ -471,11 +471,11 @@ done:
   return status;
 }
 
-static ares_bool_t ares__server_in_newconfig(struct server_state *server,
+static ares_bool_t ares__server_in_newconfig(const struct server_state *server,
                                              ares__llist_t             *srvlist)
 {
   ares__llist_node_t   *node;
-  ares_channel_t     *channel = server->channel;
+  const ares_channel_t *channel = server->channel;
 
   for (node = ares__llist_node_first(srvlist); node != NULL;
        node = ares__llist_node_next(node)) {