diff --git a/src/util.cpp b/src/util.cpp
index 67091e0f..48f92d05 100644
--- a/src/util.cpp
+++ b/src/util.cpp
@@ -49,7 +49,7 @@ namespace util
  * @param key Object to insert.
  * @param ttl Time to live in milliseonds.
  */
-    void ttl_set::emplace(const std::string key, uint64_t ttl_milli)
+    void ttl_set::emplace(const std::string key, const uint64_t ttl_milli)
     {
         ttlmap[key] = util::get_epoch_milliseconds() + ttl_milli;
     }
@@ -188,7 +188,7 @@ namespace util
     }
 
     // Provide a safe std::string overload for realpath
-    std::string realpath(std::string path)
+    std::string realpath(const std::string &path)
     {
         std::array<char, PATH_MAX> buffer;
         ::realpath(path.c_str(), buffer.data());
@@ -216,7 +216,7 @@ namespace util
     }
 
     // Kill a process with a signal and wait until it stops running.
-    int kill_process(const pid_t pid, const bool wait, int signal)
+    int kill_process(const pid_t pid, const bool wait, const int signal)
     {
         if (kill(pid, signal) == -1)
         {
diff --git a/src/util.hpp b/src/util.hpp
index 65cbf5f4..e326c9b1 100644
--- a/src/util.hpp
+++ b/src/util.hpp
@@ -60,7 +60,7 @@ namespace util
         std::unordered_map<std::string, uint64_t> ttlmap;
 
     public:
-        void emplace(const std::string key, uint64_t ttl_milli);
+        void emplace(const std::string key, const uint64_t ttl_milli);
         void erase(const std::string &key);
         bool exists(const std::string &key);
     };
@@ -86,13 +86,13 @@ namespace util
 
     int version_compare(const std::string &x, const std::string &y);
 
-    std::string realpath(std::string path);
+    std::string realpath(const std::string &path);
 
     void mask_signal();
 
     void unmask_signal();
 
-    int kill_process(const pid_t pid, const bool wait, int signal = SIGINT);
+    int kill_process(const pid_t pid, const bool wait, const int signal = SIGINT);
 
     bool is_dir_exists(std::string_view path);