feat(mosq): Allow user to enable SYS topic

Mosquitto provides several topics under $SYS/# to capture logs and load
statistics. This allows users to enable it.

components/mosquitto/CMakeLists.txt

@@ -21,7 +21,6 @@ set(m_srcs
         ${m_lib_dir}/handle_pubrec.c
         ${m_lib_dir}/handle_pubrel.c
         ${m_lib_dir}/handle_ping.c
-        ${m_lib_dir}/time_mosq.c
         ${m_lib_dir}/utf8_mosq.c
 
         ${m_src_dir}/bridge.c
@@ -75,6 +74,7 @@ idf_component_register(SRCS ${m_srcs}
                             port/config.c
                             port/signals.c
                             port/broker.c
+                            port/mosq_time.c
                             port/files.c
                             port/net__esp_tls.c
                             port/sysconf.c
@@ -82,9 +82,12 @@ idf_component_register(SRCS ${m_srcs}
                                       ${m_incl_dir} ${m_lib_dir} ${m_deps_dir}
                     INCLUDE_DIRS ${m_incl_dir} port/include
                     REQUIRES esp-tls
-                    PRIV_REQUIRES newlib sock_utils)
+                    PRIV_REQUIRES newlib sock_utils esp_timer)
 
 target_compile_definitions(${COMPONENT_LIB} PRIVATE "WITH_BROKER")
+if (CONFIG_MOSQ_ENABLE_SYS)
+    target_compile_definitions(${COMPONENT_LIB} PRIVATE "WITH_SYS_TREE")
+endif()
 target_compile_options(${COMPONENT_LIB} PRIVATE "-Wno-format")
 
 # Some mosquitto source unconditionally define `_GNU_SOURCE` which collides with IDF build system

components/mosquitto/Kconfig

@@ -0,0 +1,15 @@
+menu "Mosquitto"
+
+    config MOSQ_ENABLE_SYS
+        bool "Enable $SYS topics"
+        default n
+        help
+            Enable the $SYS topics for the broker
+
+    config MOSQ_SYS_UPDATE_INTERVAL
+        int "Update interval for the SYS topic"
+        default 10
+        depends on MOSQ_ENABLE_SYS
+        help
+            Time in seconds for the update of the $SYS topics for the broker
+endmenu

components/mosquitto/port/config.c

@@ -3,7 +3,7 @@
  *
  * SPDX-License-Identifier: EPL-2.0
  *
- * SPDX-FileContributor: 2024 Espressif Systems (Shanghai) CO LTD
+ * SPDX-FileContributor: 2024-2025 Espressif Systems (Shanghai) CO LTD
  */
 #include "mosquitto_internal.h"
 #include "mosquitto_broker.h"
@@ -14,6 +14,7 @@
 #include "utlist.h"
 #include "lib_load.h"
 #include "syslog.h"
+#include "sdkconfig.h"
 
 
 void config__init(struct mosquitto__config *config)
@@ -66,7 +67,7 @@ void config__init(struct mosquitto__config *config)
     config->log_file = NULL;
 
     config->log_facility = LOG_DAEMON;
-    config->log_dest = MQTT3_LOG_STDERR | MQTT3_LOG_DLT;
+    config->log_dest = MQTT3_LOG_STDERR | MQTT3_LOG_TOPIC;
     if (db.verbose) {
         config->log_type = UINT_MAX;
     } else {
@@ -91,7 +92,9 @@ void config__init(struct mosquitto__config *config)
     config->queue_qos0_messages = false;
     config->retain_available = true;
     config->set_tcp_nodelay = false;
-    config->sys_interval = 10;
+#if defined(WITH_SYS_TREE)
+    config->sys_interval = CONFIG_MOSQ_SYS_UPDATE_INTERVAL;
+#endif
     config->upgrade_outgoing_qos = false;
 
     config->daemon = false;
@@ -236,7 +239,7 @@ char *misc__trimblanks(char *str)
 
 // Dummy definition of fork() to work around IDF warning: " warning: _fork is not implemented and will always fail"
 // fork() is used in mosquitto.c to deamonize the broker, which we do not call.
-pid_t fork (void)
+pid_t fork(void)
 {
     abort();
     return 0;

components/mosquitto/port/mosq_time.c

@@ -0,0 +1,19 @@
+/*
+ * SPDX-FileCopyrightText: 2025 Espressif Systems (Shanghai) CO LTD
+ *
+ * SPDX-License-Identifier: Apache-2.0
+ */
+
+#include <time.h>
+#include "time_mosq.h"
+
+#include "esp_timer.h"
+
+void mosquitto_time_init(void)
+{
+}
+
+time_t mosquitto_time(void)
+{
+    return esp_timer_get_time() / 1000000; // Convert microseconds to seconds
+}