reopen logfile if cores last_log_rotation changed

since we no longer SIGHUP the core to rotate the logfile, we need to reopen the logfile in the module manually.

references:
 - ConSol-Monitoring/omd#146

src/logger.c

@@ -82,6 +82,17 @@ void open_logfile()
         logger(LG_WARN, "Cannot open logfile %s: %s", g_logfile_path, strerror(errno));
 }
 
+void reopen_logfile()
+{
+    lock_mutex_or_die(&g_log_file_mutex);
+    if(g_logfile)
+        fclose(g_logfile);
+    g_logfile = fopen(g_logfile_path, "a");
+    if (!g_logfile)
+        logger(LG_WARN, "Cannot open logfile %s: %s", g_logfile_path, strerror(errno));
+    unlock_mutex_or_die(&g_log_file_mutex);
+}
+
 void close_logfile()
 {
     lock_mutex_or_die(&g_log_file_mutex);
@@ -112,7 +123,7 @@ void logger(int priority, const char *loginfo, ...)
             char timestring[64];
             time_t now_t = time(0);
             struct tm now; localtime_r(&now_t, &now);
-            strftime(timestring, 64, "%F %T ", &now); 
+            strftime(timestring, 64, "%F %T ", &now);
             fputs(timestring, g_logfile);
 
             /* write log message */
@@ -124,4 +135,3 @@ void logger(int priority, const char *loginfo, ...)
         unlock_mutex_or_die(&g_log_file_mutex);
     }
 }
-

src/logger.h

@@ -43,6 +43,7 @@ void logger(int priority, const char *loginfo, ...);
 void initialize_logger();
 void open_logfile();
 void close_logfile();
+void reopen_logfile();
 
 #ifdef __cplusplus
 }

src/module.c

@@ -96,6 +96,7 @@ char g_hidden_custom_var_prefix[256];
 int g_service_authorization = AUTH_LOOSE;
 int g_group_authorization = AUTH_STRICT;
 int g_data_encoding = ENCODING_UTF8;
+time_t g_last_log_rotation = -1;
 
 void *client_thread(void *data __attribute__ ((__unused__)));
 
@@ -458,6 +459,19 @@ int broker_program(int event_type __attribute__ ((__unused__)), void *data __att
     return 0;
 }
 
+int broker_program_data(int event_type __attribute__ ((__unused__)), void *data)
+{
+    // check cores last_log_rotation if we should reopen our logfile
+    struct nebstruct_program_status_struct *pd = (struct nebstruct_program_status_struct *)data;
+    if (pd->type == NEBTYPE_PROGRAMSTATUS_UPDATE) {
+        if(pd->last_log_rotation != g_last_log_rotation) {
+            g_last_log_rotation = pd->last_log_rotation;
+            reopen_logfile();
+        }
+    }
+    return 0;
+}
+
 static void schedule_timeperiods_cache_update(struct nm_event_execution_properties *evprop)
 {
     g_counters[COUNTER_NEB_CALLBACKS]++;
@@ -552,6 +566,7 @@ void register_callbacks()
     neb_register_callback(NEBCALLBACK_STATE_CHANGE_DATA,     g_nagios_handle, 0, broker_state); // only for trigger 'state'
     neb_register_callback(NEBCALLBACK_ADAPTIVE_PROGRAM_DATA, g_nagios_handle, 0, broker_program); // only for trigger 'program'
     neb_register_callback(NEBCALLBACK_PROCESS_DATA,          g_nagios_handle, 0, broker_process); // used for starting threads
+    neb_register_callback(NEBCALLBACK_PROGRAM_STATUS_DATA,   g_nagios_handle, 0, broker_program_data); // used for reopening logfile
     schedule_event(1, schedule_timeperiods_cache_update, NULL);
 }
 
@@ -567,6 +582,7 @@ void deregister_callbacks()
     neb_deregister_callback(NEBCALLBACK_STATE_CHANGE_DATA,     broker_state);
     neb_deregister_callback(NEBCALLBACK_ADAPTIVE_PROGRAM_DATA, broker_program);
     neb_deregister_callback(NEBCALLBACK_PROCESS_DATA,          broker_program);
+    neb_deregister_callback(NEBCALLBACK_PROGRAM_STATUS_DATA,   broker_program);
 }