Index: uspace/app/bithenge/tree.c
===================================================================
--- uspace/app/bithenge/tree.c	(revision ff788c3110abf34a493f3fc6eb3c367b57a6d1e2)
+++ uspace/app/bithenge/tree.c	(revision e8e31d9e852422d266d715e52dcd401c4d66a48b)
@@ -80,4 +80,50 @@
 }
 
+typedef struct {
+	bithenge_node_t *key;
+	bithenge_node_t **out;
+} get_for_each_data_t;
+
+static int get_for_each_func(bithenge_node_t *key, bithenge_node_t *value,
+    void *raw_data)
+{
+	get_for_each_data_t *data = (get_for_each_data_t *)raw_data;
+	bool equal = bithenge_node_equal(key, data->key);
+	bithenge_node_dec_ref(key);
+	if (equal) {
+		*data->out = value;
+		return EEXIST;
+	}
+	bithenge_node_dec_ref(value);
+	return EOK;
+}
+
+/** Get a child of a node. Takes ownership of the key. If the node does not
+ * provide this function, for_each will be used as an alternative, which may be
+ * very slow.
+ * @memberof bithenge_node_t
+ * @param self The internal node to find a child of.
+ * @param key The key to search for.
+ * @param[out] out Holds the found node.
+ * @return EOK on success, ENOENT if not found, or another error code from
+ * errno.h. */
+int bithenge_node_get(bithenge_node_t *self, bithenge_node_t *key,
+    bithenge_node_t **out)
+{
+	assert(self->type == BITHENGE_NODE_INTERNAL);
+	if (self->internal_ops->get)
+		return self->internal_ops->get(self, key, out);
+	*out = NULL;
+	get_for_each_data_t data = {key, out};
+	int rc = bithenge_node_for_each(self, get_for_each_func, &data);
+	bithenge_node_dec_ref(key);
+	if (rc == EEXIST && *out)
+		return EOK;
+	if (rc == EOK)
+		rc = ENOENT;
+	bithenge_node_dec_ref(*out);
+	return rc;
+}
+
 typedef struct
 {
Index: uspace/app/bithenge/tree.h
===================================================================
--- uspace/app/bithenge/tree.h	(revision ff788c3110abf34a493f3fc6eb3c367b57a6d1e2)
+++ uspace/app/bithenge/tree.h	(revision e8e31d9e852422d266d715e52dcd401c4d66a48b)
@@ -94,4 +94,7 @@
 	/** @copydoc bithenge_node_t::bithenge_node_for_each */
 	int (*for_each)(bithenge_node_t *self, bithenge_for_each_func_t func, void *data);
+	/** @copydoc bithenge_node_t::bithenge_node_get */
+	int (*get)(bithenge_node_t *self, bithenge_node_t *key,
+	    bithenge_node_t **out);
 	/** Destroys the internal node.
 	 * @param self The node to destroy. */
@@ -131,4 +134,7 @@
 	return self->internal_ops->for_each(self, func, data);
 }
+
+int bithenge_node_get(bithenge_node_t *, bithenge_node_t *,
+    bithenge_node_t **);
 
 /** Get the value of a boolean node.