fix: ftell failure handling

src/file.c

@@ -47,6 +47,12 @@ bool file_update(File *file) {
   // read file length
   fseek(file_pointer, 0, SEEK_END);
   length = ftell(file_pointer);
+  if (length == -1L) {
+    file->error = true;
+    fclose(file_pointer);
+    log_error("Cannot get file length for '%s'", file->path);
+    return false;
+  }
   // init buffer
   fseek(file_pointer, 0, SEEK_SET);
   file->content = malloc(length + 1);