Allow debug logging from multiple threads (#107)

Co-authored-by: Mattias Axelsson <[email protected]>
AxisCommunications · Apr 15, 2024 · 285af5f · 285af5f
1 parent fa51b37
commit 285af5f
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Showing 3 changed files with 17 additions and 10 deletions.
diff --git a/app/dockerdwrapperwithcompose.c b/app/dockerdwrapperwithcompose.c
@@ -789,7 +789,7 @@ int main(int argc, char** argv) {
         return EX_SOFTWARE;
     }
 
-    log_settings.debug = is_app_log_level_debug(app_state.param_handle);
+    log_debug_set(is_app_log_level_debug(app_state.param_handle));
 
     init_signals();
 
@@ -801,7 +801,7 @@ int main(int argc, char** argv) {
 
         main_loop_run();
 
-        log_settings.debug = is_app_log_level_debug(app_state.param_handle);
+        log_debug_set(is_app_log_level_debug(app_state.param_handle));
 
         stop_dockerd();
     }

diff --git a/app/log.c b/app/log.c
@@ -1,8 +1,9 @@
 #include "log.h"
-#include <glib.h>
 #include <stdio.h>
 #include <syslog.h>
 
+static volatile int debug_log_enabled;  // Accessed using g_atomic_int_get/set only
+
 static int log_level_to_syslog_priority(GLogLevelFlags log_level) {
     if (log_level == G_LOG_LEVEL_NON_FATAL_ERROR)
         log_level = G_LOG_LEVEL_ERROR;
@@ -44,24 +45,24 @@ static const char* log_level_to_string(GLogLevelFlags log_level) {
     }
 }
 
-static bool log_threshold_met(GLogLevelFlags log_level, const struct log_settings* settings) {
-    return settings->debug || (log_level & ~G_LOG_LEVEL_DEBUG);
+static bool log_threshold_met(GLogLevelFlags log_level) {
+    return g_atomic_int_get(&debug_log_enabled) || (log_level & ~G_LOG_LEVEL_DEBUG);
 }
 
 static void log_to_syslog(__attribute__((unused)) const char* log_domain,
                           GLogLevelFlags log_level,
                           const char* message,
-                          gpointer settings_void_ptr) {
-    if (log_threshold_met(log_level, settings_void_ptr))
+                          __attribute__((unused)) gpointer settings_void_ptr) {
+    if (log_threshold_met(log_level))
         syslog(log_level_to_syslog_priority(log_level), "%s", message);
 }
 
 // Timestamp format and log level have been chosen to match that of dockerd
 static void log_to_stdout(__attribute__((unused)) const char* log_domain,
                           GLogLevelFlags log_level,
                           const char* message,
-                          gpointer settings_void_ptr) {
-    if (log_threshold_met(log_level, settings_void_ptr)) {
+                          __attribute__((unused)) gpointer settings_void_ptr) {
+    if (log_threshold_met(log_level)) {
         GDateTime* now = g_date_time_new_now_local();
         g_autofree char* now_text = g_date_time_format(now, "%Y-%m-%dT%T.%f000%:z");
         g_date_time_unref(now);
@@ -78,3 +79,7 @@ void log_init(struct log_settings* settings) {
                       settings->destination == log_dest_syslog ? log_to_syslog : log_to_stdout,
                       settings);
 }
+
+void log_debug_set(bool enabled) {
+    g_atomic_int_set(&debug_log_enabled, enabled);
+}
diff --git a/app/log.h b/app/log.h
@@ -1,11 +1,11 @@
 #pragma once
+#include <glib.h>
 #include <stdbool.h>
 
 enum log_destination { log_dest_stdout, log_dest_syslog };
 
 struct log_settings {
     enum log_destination destination;
-    bool debug;
 };
 
 // Set up g_log to log to either stdout or syslog.
@@ -15,6 +15,8 @@ struct log_settings {
 // the struct must live until the process exits.
 void log_init(struct log_settings* settings);
 
+void log_debug_set(bool enabled);
+
 // Replacement for G_LOG_LEVEL_ERROR, which is fatal.
 #define G_LOG_LEVEL_NON_FATAL_ERROR (1 << G_LOG_LEVEL_USER_SHIFT)