len = strlen(dirname) + 30;
        filename = malloc(sizeof(char) * len);
+       if (!filename) {
+               perror("malloc");
+               goto out_dir;
+       }
 
        if (uname(&sysdata) == 0) {
                len += strlen(sysdata.nodename) + strlen(sysdata.release);
                filename = realloc(filename, sizeof(char) * len);
 
-               if (filename == NULL) {
+               if (!filename) {
                        perror("realloc");
-                       return NULL;
+                       goto out_dir;
                }
 
                snprintf(filename, len - 1, "%s/benchmark_%s_%s_%li.log",
        if (output == NULL) {
                perror("fopen");
                fprintf(stderr, "error: unable to open logfile\n");
+               goto out;
        }
 
        fprintf(stdout, "Logfile: %s\n", filename);
 
-       free(filename);
        fprintf(output, "#round load sleep performance powersave percentage\n");
+out:
+       free(filename);
+out_dir:
+       closedir(dir);
        return output;
 }