preparation for dfs algorithm

dfs.c

+/*
+DFS(G,v)   ( v is the vertex where the search starts )
+         Stack S := {};   ( start with an empty stack )
+         for each vertex u, set visited[u] := false;
+         push S, v;
+         while (S is not empty) do
+            u := pop S;
+            if (not visited[u]) then
+               visited[u] := true;
+               for each unvisited neighbour w of u
+                  push S, w;
+            end if
+         end while
+      END DFS()
+*/
+#include "dfs.h"
+
+void stack_enqueue(struct node *n, struct list_head *stack)
+{
+	if (list_empty(stack))
+		INIT_LIST_HEAD(stack);
+	list_add(&node->list, stack);
+}
+
+struct node *stack_dequeue(struct list_head *stack)
+{
+	struct node *n;
+
+	return list_first_entry(stack, struct node, list);
+}
+
+void add_visited(struct node *n, struct list_head *visited)
+{
+	if (list_empty(visited))
+		INIT_LIST_HEAD(visited);
+	list_add(&node->list, visited);
+}
+
+bool is_visited(struct node *n, struct list_head *visited)
+{
+	struct node *tmp;
+
+	list_for_each_entry(tmp, visited, list) {
+		if (strncmp(tmp->path, n->path, 1024) == 0)
+			return true;
+	}
+
+	return false;
+}
\ No newline at end of file

dfs.h

+#ifndef DFS_H
+#define DFS_H
+#include "common.h"
+
+struct node {
+	struct list_head list;
+	char *path;
+	char *name;
+};
+
+void enqueue_stack(struct node *n, struct list_head *stack);
+struct node *dequeue_stack(struct list_head *stack);
+void add_visited(struct node *n, struct list_head *visited);
+bool is_visited(struct node *n, struct list_head *visited);
+#endif
\ No newline at end of file

dongle_infrastructure.c

@@ -17,6 +17,7 @@
 
 #include "dongle_infrastructure.h"
 #include "dongle.h"
+#include "dfs.h"
 
 enum {
 	DEV,
@@ -28,6 +29,8 @@ const struct blobmsg_policy dev_policy[__DEV_MAX] = {
 };
 
 LIST_HEAD(devices);
+LIST_HEAD(visited);
+LIST_HEAD(unvisited);
 
 int devices_status(struct uloop_timeout *t)
 {