From 391a8674fcd886165dc02154d3ef0d3377f2c840 Mon Sep 17 00:00:00 2001
From: Saverio Proto <zioproto@gmail.com>
Date: Mon, 2 Jun 2014 13:54:47 +0200
Subject: [PATCH] Provide thread-safety to functions that return pointers to
 meshlink_node_t.   - The mesh->nodes tree can be updated by the library
 thread at any time,     so it must be protected by a mutex or rwlock.

---
 src/meshlink.c          |  6 ++++++
 src/meshlink_internal.h |  1 +
 src/node.c              | 15 ++++++++++++++-
 3 files changed, 21 insertions(+), 1 deletion(-)

diff --git a/src/meshlink.c b/src/meshlink.c
index 72e27b0f..fc8408ad 100644
--- a/src/meshlink.c
+++ b/src/meshlink.c
@@ -735,6 +735,7 @@ meshlink_handle_t *meshlink_open(const char *confbase, const char *name) {
 	mesh->confbase = xstrdup(confbase);
 	mesh->name = xstrdup(name);
 	pthread_mutex_init ( &(mesh->outpacketqueue_mutex), NULL);
+	pthread_mutex_init ( &(mesh->nodes_mutex), NULL);
 	event_loop_init(&mesh->loop);
 	mesh->loop.data = mesh;
 
@@ -898,12 +899,17 @@ meshlink_node_t *meshlink_get_node(meshlink_handle_t *mesh, const char *name) {
 size_t meshlink_get_all_nodes(meshlink_handle_t *mesh, meshlink_node_t **nodes, size_t nmemb) {
 	size_t i = 0;
 
+	//lock mesh->nodes
+	pthread_mutex_lock(&(mesh->nodes_mutex));
+
 	for splay_each(node_t, n, mesh->nodes) {
 		if(i < nmemb)
 			nodes[i] = (meshlink_node_t *)n;
 		i++;
 	}
 
+	pthread_mutex_unlock(&(mesh->nodes_mutex));
+
 	return i;
 }
 
diff --git a/src/meshlink_internal.h b/src/meshlink_internal.h
index c58c4773..cb60416d 100644
--- a/src/meshlink_internal.h
+++ b/src/meshlink_internal.h
@@ -61,6 +61,7 @@ struct meshlink_handle {
 
 	pthread_t thread;
 	pthread_mutex_t outpacketqueue_mutex;
+	pthread_mutex_t nodes_mutex;
 	event_loop_t loop;
 	listen_socket_t listen_socket[MAXSOCKETS];
 	int listen_sockets;
diff --git a/src/node.c b/src/node.c
index 3e4dec95..0a7b4a52 100644
--- a/src/node.c
+++ b/src/node.c
@@ -36,13 +36,17 @@ static int node_compare(const node_t *a, const node_t *b) {
 }
 
 void init_nodes(meshlink_handle_t *mesh) {
+	pthread_mutex_lock(&(mesh->nodes_mutex));
 	mesh->nodes = splay_alloc_tree((splay_compare_t) node_compare, (splay_action_t) free_node);
 	node_udp_cache = hash_alloc(0x100, sizeof(sockaddr_t));
+	pthread_mutex_unlock(&(mesh->nodes_mutex));
 }
 
 void exit_nodes(meshlink_handle_t *mesh) {
+	pthread_mutex_lock(&(mesh->nodes_mutex));
 	hash_free(node_udp_cache);
 	splay_delete_tree(mesh->nodes);
+	pthread_mutex_unlock(&(mesh->nodes_mutex));
 }
 
 node_t *new_node(void) {
@@ -81,25 +85,34 @@ void free_node(node_t *n) {
 }
 
 void node_add(meshlink_handle_t *mesh, node_t *n) {
+	pthread_mutex_lock(&(mesh->nodes_mutex));
 	n->mesh = mesh;
 	splay_insert(mesh->nodes, n);
+	pthread_mutex_unlock(&(mesh->nodes_mutex));
 }
 
 void node_del(meshlink_handle_t *mesh, node_t *n) {
+	pthread_mutex_lock(&(mesh->nodes_mutex));
 	timeout_del(&mesh->loop, &n->mtutimeout);
 
 	for splay_each(edge_t, e, n->edge_tree)
 		edge_del(mesh, e);
 
 	splay_delete(mesh->nodes, n);
+	pthread_mutex_unlock(&(mesh->nodes_mutex));
 }
 
 node_t *lookup_node(meshlink_handle_t *mesh, char *name) {
 	node_t n = {NULL};
+	node_t* result;
 
 	n.name = name;
 
-	return splay_search(mesh->nodes, &n);
+	pthread_mutex_lock(&(mesh->nodes_mutex));
+	result = splay_search(mesh->nodes, &n);
+	pthread_mutex_unlock(&(mesh->nodes_mutex));
+
+	return result;
 }
 
 node_t *lookup_node_udp(meshlink_handle_t *mesh, const sockaddr_t *sa) {
-- 
2.39.2