control_socket acquire: get the pointer from priv_data

Do not assume that (struct module) is first in the (struct control_state)
anymore in particular and in any structure in general.

Author: MartinPulec

src/audio/filter/controlport_stats.cpp

@@ -3,7 +3,7 @@
  * @author Martin Piatka     <[email protected]>
  */
 /*
- * Copyright (c) 2022 CESNET, z. s. p. o.
+ * Copyright (c) 2022-2025 CESNET
  * All rights reserved.
  *
  * Redistribution and use in source and binary forms, with or without
@@ -55,7 +55,9 @@
 struct state_controlport_stats{
         state_controlport_stats(struct module *mod) : mod(MODULE_CLASS_DATA, mod, this)
         {
-                control = (control_state *) (get_module(get_root_module(mod), "control"));
+                control = (control_state *) (get_module(get_root_module(mod),
+                                                        "control"))
+                              ->priv_data;
         }
 
         module_raii mod;

src/module.h

@@ -106,8 +106,9 @@ typedef void (*notify_t)(struct module *);
 struct module {
         enum module_class cls;
         notify_t new_message; ///< if set, notifies module that new message is in queue, receiver lock is hold during the call
-        void *priv_data;      ///< can be used to store state pointer for
-                              ///< new_message(); uneeded otherwise
+        void *priv_data; ///< optional; can be used to store state pointer for
+                         ///< new_message() or to retreive the state from the
+                         ///< module (control_socket)
         char name[128]; ///< optional name of the module. May be used for indexing.
 
         struct module_priv_state *module_priv;

src/rtp/video_decoders.cpp

@@ -341,7 +341,9 @@ struct state_video_decoder
                 mod.priv_data = this;
                 mod.new_message = decoder_process_message;
                 module_register(&mod, parent);
-                control = (struct control_state *) get_module(get_root_module(parent), "control");
+                control = (struct control_state *) get_module(
+                              get_root_module(parent), "control")
+                              ->priv_data;
         }
         ~state_video_decoder() {
                 module_done(&mod);

src/transmit.cpp

@@ -264,8 +264,10 @@ struct tx *tx_init(struct module *parent, unsigned mtu, enum tx_media_type media
 
         tx->bitrate = bitrate;
 
-        if(parent)
-                tx->control = (struct control_state *) get_module(get_root_module(parent), "control");
+        if (parent) {
+                tx->control = (struct control_state *) get_module(
+                    get_root_module(parent), "control")->priv_data;
+        }
 
         return tx;
 }

src/video_rxtx/ultragrid_rtp.cpp

@@ -3,7 +3,7 @@
  * @author Martin Pulec     <[email protected]>
  */
 /*
- * Copyright (c) 2013-2023 CESNET z.s.p.o.
+ * Copyright (c) 2013-2025 CESNET
  * All rights reserved.
  *
  * Redistribution and use in source and binary forms, with or without
@@ -93,7 +93,7 @@ ultragrid_rtp_video_rxtx::ultragrid_rtp_video_rxtx(const map<string, param_u> &p
         }
 
         m_control = (struct control_state *) get_module(
-            get_root_module(m_common.parent), "control");
+            get_root_module(m_common.parent), "control")->priv_data;
 }
 
 ultragrid_rtp_video_rxtx::~ultragrid_rtp_video_rxtx()