Revert "Merge pull request 'Merge all 5 batch PRs: security, CLI features, protocol, performance, tests/docs' (#143) from merge-all-v2 into main"

This reverts commit 29f4f8cde6, reversing
changes made to c6bf7bb84e.

src/shared/log.c

@@ -5,21 +5,19 @@
 
 static const char* log_level_strings[] = {"DEBUG", "INFO", "WARN", "ERROR"};
 static LogLevel current_log_level = LOG_LEVEL_WARNING;
-static FILE* log_fp = NULL;
 
 void set_log_level(LogLevel level) {
   current_log_level = level;
 }
 
-void log_set_file(FILE* fp) {
-  log_fp = fp;
-}
-
 void log_message(LogLevel log_level, const char* format, ...) {
   if (log_level < current_log_level)
     return;
   time_t now = time(NULL);
-  const struct tm* t = localtime(&now);
+  struct tm result_buf;
+  const struct tm* t = localtime_r(&now, &result_buf);
+  if (t == NULL)
+    return;
 
   fprintf(stderr, "%04d-%02d-%02d %02d:%02d:%02d [%s]: ", t->tm_year + 1900, t->tm_mon + 1,
           t->tm_mday, t->tm_hour, t->tm_min, t->tm_sec, log_level_strings[log_level]);
@@ -29,14 +27,4 @@ void log_message(LogLevel log_level, const char* format, ...) {
   vfprintf(stderr, format, args);
   va_end(args);
   fprintf(stderr, "\n");
-
-  if (log_fp) {
-    fprintf(log_fp, "%04d-%02d-%02d %02d:%02d:%02d [%s]: ", t->tm_year + 1900, t->tm_mon + 1,
-            t->tm_mday, t->tm_hour, t->tm_min, t->tm_sec, log_level_strings[log_level]);
-    va_start(args, format);
-    vfprintf(log_fp, format, args);
-    va_end(args);
-    fprintf(log_fp, "\n");
-    fflush(log_fp);
-  }
 }