Add severeal helpers (get methods) for volume key.

crypt_volume_key_length() for key length
crypt_volume_key_get_key() to access key data (if initialized)
crypt_volume_key_description() for kernel key description
crypt_volume_key_kernel_key_type() for kernel keyring key type

lib/internal.h

@@ -69,9 +69,13 @@ struct volume_key *crypt_alloc_volume_key(size_t keylength, const char *key);
 struct volume_key *crypt_generate_volume_key(struct crypt_device *cd, size_t keylength,
 					     key_quality_info quality);
 void crypt_free_volume_key(struct volume_key *vk);
+const char *crypt_volume_key_get_key(const struct volume_key *vk);
+size_t crypt_volume_key_length(const struct volume_key *vk);
 int crypt_volume_key_set_description(struct volume_key *key,
 				     const char *key_description, key_type_t keyring_key_type);
 int crypt_volume_key_set_description_by_name(struct volume_key *vk, const char *key_name);
+key_type_t crypt_volume_key_kernel_key_type(const struct volume_key *vk);
+const char *crypt_volume_key_description(const struct volume_key *vk);
 void crypt_volume_key_set_id(struct volume_key *vk, int id);
 int crypt_volume_key_get_id(const struct volume_key *vk);
 void crypt_volume_key_add_next(struct volume_key **vks, struct volume_key *vk);

lib/volumekey.c

@@ -39,6 +39,20 @@ struct volume_key *crypt_alloc_volume_key(size_t keylength, const char *key)
 	return vk;
 }
 
+const char *crypt_volume_key_get_key(const struct volume_key *vk)
+{
+	assert(vk);
+
+	return (const char *)vk->key;
+}
+
+size_t crypt_volume_key_length(const struct volume_key *vk)
+{
+	assert(vk);
+
+	return vk->keylength;
+}
+
 int crypt_volume_key_set_description(struct volume_key *vk,
 				     const char *key_description, key_type_t keyring_key_type)
 {
@@ -65,6 +79,21 @@ int crypt_volume_key_set_description_by_name(struct volume_key *vk, const char *
 	return crypt_volume_key_set_description(vk, key_description, keyring_key_type);
 }
 
+const char *crypt_volume_key_description(const struct volume_key *vk)
+{
+	assert(vk);
+
+	return vk->key_description;
+}
+
+
+key_type_t crypt_volume_key_kernel_key_type(const struct volume_key *vk)
+{
+	assert(vk);
+
+	return vk->keyring_key_type;
+}
+
 void crypt_volume_key_set_id(struct volume_key *vk, int id)
 {
 	if (vk && id >= 0)