diff --git a/src/main/event.c b/src/main/event.c
index a81688aa0..5847923ea 100644
--- a/src/main/event.c
+++ b/src/main/event.c
@@ -117,7 +117,7 @@ register_event(char *name)
 }
 
 int
-get_event_id(char *name)
+get_event_id(const char *name)
 {
 	struct hash_item *item;
 	int namelen;
diff --git a/src/main/event.h b/src/main/event.h
index 724c55471..b63fcdb02 100644
--- a/src/main/event.h
+++ b/src/main/event.h
@@ -95,7 +95,7 @@ void unregister_event_hooks(struct event_hook_info *hooks);
  * unregistration), thus it may be cached intermediatelly. */
 /* It returns the event id on success or a negative number upon failure
  * (ie. there is no such event). */
-int get_event_id(char *name);
+int get_event_id(const char *name);
 
 /* This looks up the events table and returns the name of a given event
  * @id. */
diff --git a/src/util/hash.c b/src/util/hash.c
index b34286360..ed3c80606 100644
--- a/src/util/hash.c
+++ b/src/util/hash.c
@@ -25,7 +25,7 @@
 #define hash_mask(n) (hash_size(n) - 1)
 #define hash_size(n) (1 << (n))
 
-static hash_value_T strhash(char *k, unsigned int length, hash_value_T initval);
+static hash_value_T strhash(const char *k, unsigned int length, hash_value_T initval);
 
 static inline struct hash *
 init_hash(unsigned int width, hash_func_T func)
@@ -82,7 +82,7 @@ free_hash(struct hash **hashp)
 /** @returns hash_item if ok, NULL if error.
  * @relates hash */
 struct hash_item *
-add_hash_item(struct hash *hash, char *key, unsigned int keylen,
+add_hash_item(struct hash *hash, const char *key, unsigned int keylen,
 	      void *value)
 {
 	hash_value_T hashval;
@@ -103,7 +103,7 @@ add_hash_item(struct hash *hash, char *key, unsigned int keylen,
 
 /** @relates hash */
 struct hash_item *
-get_hash_item(struct hash *hash, char *key, unsigned int keylen)
+get_hash_item(struct hash *hash, const char *key, unsigned int keylen)
 {
 	struct list_head *list;
 	struct hash_item *item;
@@ -151,7 +151,7 @@ del_hash_item(struct hash *hash, struct hash_item *item)
  * @param length	the length of the key
  * @param initval	the previous hash, or an arbitrary value */
 static hash_value_T
-strhash(char *k,
+strhash(const char *k,
 	unsigned int length,
 	hash_value_T initval)
 {
diff --git a/src/util/hash.h b/src/util/hash.h
index 9f11444d3..624144266 100644
--- a/src/util/hash.h
+++ b/src/util/hash.h
@@ -11,12 +11,12 @@ extern "C" {
  * happen when this will be of other length, but it should still work ok.
  * --pasky */
 typedef unsigned long hash_value_T;
-typedef hash_value_T (* hash_func_T)(char *key, unsigned int keylen, hash_value_T magic);
+typedef hash_value_T (* hash_func_T)(const char *key, unsigned int keylen, hash_value_T magic);
 
 struct hash_item {
 	LIST_HEAD(struct hash_item);
 
-	char *key;
+	const char *key;
 	unsigned int keylen;
 	void *value;
 };
@@ -31,8 +31,8 @@ struct hash *init_hash8(void);
 
 void free_hash(struct hash **hashp);
 
-struct hash_item *add_hash_item(struct hash *hash, char *key, unsigned int keylen, void *value);
-struct hash_item *get_hash_item(struct hash *hash, char *key, unsigned int keylen);
+struct hash_item *add_hash_item(struct hash *hash, const char *key, unsigned int keylen, void *value);
+struct hash_item *get_hash_item(struct hash *hash, const char *key, unsigned int keylen);
 void del_hash_item(struct hash *hash, struct hash_item *item);
 
 /** @relates hash */