Implement logger functionality and signal handling: add Logger structure with mutex, logging functions, and handle SIGINT in utils.

include/logger.h

@@ -0,0 +1,21 @@
+#ifndef __LOGGER_H__
+#define __LOGGER_H__
+
+#include "main.h"
+#include "rfid_handler.h"
+#include "utils.h"
+
+typedef struct
+{
+    pthread_mutex_t lock;
+    FILE *f_log;
+} Logger;
+
+Logger *initLogger(const char *_filename);
+int logErrorEvent(Logger *_logger, const char *_message);
+int logWarningEvent(Logger *_logger, const char *_message);
+int logHardwareEvent(Logger *_logger, const char *_event_origin, const char *_message);
+int logInfoEvent(Logger *_logger, const char *_message);
+int endLogger(Logger *_logger);
+
+#endif