Fix print functions

src/election.c

@@ -119,17 +119,17 @@ void awdl_election_run(struct awdl_election_state *state, const struct awdl_peer
 	}
 }
 
-int awdl_election_tree_print(const struct awdl_election_state *state, char *str, size_t len) {
+int awdl_election_tree_print(const struct awdl_election_state *state, char *str, int len) {
 	char *cur = str, *const end = str + len;
-	cur += snprintf(cur, end - cur, "%s", ether_ntoa(&state->self_addr));
+	cur += snprintf(cur, cur < end ? end - cur: 0, "%s", ether_ntoa(&state->self_addr));
 	if (state->height > 0)
-		cur += snprintf(cur, end - cur, " -> %s", ether_ntoa(&state->sync_addr));
+		cur += snprintf(cur, cur < end ? end - cur : 0, " -> %s", ether_ntoa(&state->sync_addr));
 	if (state->height > 1) {
-		cur += snprintf(cur, end - cur, " ");
+		cur += snprintf(cur, cur < end ? end - cur : 0, " ");
 		for (uint32_t i = 1; i < state->height; i++)
-			cur += snprintf(cur, end - cur, "-"); /* one dash for every intermediate hop */
-		cur += snprintf(cur, end - cur, "> %s", ether_ntoa(&state->master_addr));
+			cur += snprintf(cur, cur < end ? end - cur : 0, "-"); /* one dash for every intermediate hop */
+		cur += snprintf(cur, cur < end ? end - cur : 0, "> %s", ether_ntoa(&state->master_addr));
 	}
-	cur += snprintf(cur, end - cur, " (met %u, ctr %u)", state->master_metric, state->master_counter);
+	cur += snprintf(cur, cur < end ? end - cur : 0, " (met %u, ctr %u)", state->master_metric, state->master_counter);
 	return cur - str;
 }

src/election.h

@@ -45,7 +45,7 @@ void awdl_election_state_init(struct awdl_election_state *state, const struct et
 
 void awdl_election_run(struct awdl_election_state *state, const struct awdl_peer_state *peers);
 
-int awdl_election_tree_print(const struct awdl_election_state *state, char *str, size_t len);
+int awdl_election_tree_print(const struct awdl_election_state *state, char *str, int len);
 
 /* Util functions */
 int compare_ether_addr(const struct ether_addr *a, const struct ether_addr *b);

src/peers.c

@@ -142,29 +142,29 @@ enum peers_status awdl_peer_get(awdl_peers_t peers, const struct ether_addr *_ad
 	return PEERS_OK;
 }
 
-int awdl_peer_print(const struct awdl_peer *peer, char *str, size_t len) {
+int awdl_peer_print(const struct awdl_peer *peer, char *str, int len) {
 	char *cur = str, *const end = str + len;
 	if (strlen(peer->name))
-		cur += snprintf(cur, end - cur, "%s: ", peer->name);
+		cur += snprintf(cur, cur < end ? end - cur : 0, "%s: ", peer->name);
 	else
-		cur += snprintf(cur, end - cur, "<UNNAMED>: ");
-	cur += awdl_election_tree_print(&peer->election, cur, end - cur);
-	return end - cur;
+		cur += snprintf(cur, cur < end ? end - cur : 0, "<UNNAMED>: ");
+    cur += awdl_election_tree_print(&peer->election, cur, end - cur);
+	return cur - str;
 }
 
-int awdl_peers_print(awdl_peers_t peers, char *str, size_t len) {
+int awdl_peers_print(awdl_peers_t peers, char *str, int len) {
 	char *cur = str, *const end = str + len;
 	map_t map = (map_t) peers;
 	map_it_t it = hashmap_it_new(map);
 	struct awdl_peer *peer;
 
 	while (hashmap_it_next(it, NULL, (any_t *) &peer) == MAP_OK) {
-		cur += awdl_peer_print(peer, cur, end - cur);
-		cur += snprintf(cur, end - cur, "\n");
-	}
+        cur += awdl_peer_print(peer, cur, end - cur);
+        cur += snprintf(cur, cur < end ? end - cur : 0, "\n");
+    }
 
 	hashmap_it_free(it);
-	return end - cur;
+	return cur - str;
 }
 
 void awdl_peers_remove(awdl_peers_t peers, uint64_t before, awdl_peer_cb cb, void *arg) {

src/peers.h

@@ -76,7 +76,7 @@ enum peers_status awdl_peer_remove(awdl_peers_t peers, const struct ether_addr *
 
 enum peers_status awdl_peer_get(awdl_peers_t peers, const struct ether_addr *addr, struct awdl_peer **peer);
 
-int awdl_peer_print(const struct awdl_peer *peer, char *str, size_t len);
+int awdl_peer_print(const struct awdl_peer *peer, char *str, int len);
 
 /**
  * Apply callback to and then remove all peers matching a filter
@@ -87,7 +87,7 @@ int awdl_peer_print(const struct awdl_peer *peer, char *str, size_t len);
  */
 void awdl_peers_remove(awdl_peers_t peers, uint64_t before, awdl_peer_cb cb, void *arg);
 
-int awdl_peers_print(awdl_peers_t peers, char *str, size_t len);
+int awdl_peers_print(awdl_peers_t peers, char *str, int len);
 
 /* Iterator functions */
 typedef void *awdl_peers_it_t;

tests/test_awdl_peers.cpp

@@ -23,8 +23,10 @@ extern "C" {
 
 #include "gtest/gtest.h"
 
-static const struct ether_addr TEST_ADDR = {{ 0xc0, 0xff, 0xee,  0xc0, 0xff, 0xee }};
-static const struct ether_addr TEST_ADDR2 = {{ 0xc0, 0xff, 0xff, 0xc0, 0xff, 0xff }};
+#define TEST_ADDR(i) static const struct ether_addr TEST_ADDR##i = {{ i, i, i, i, i, i }}
+
+TEST_ADDR(0);
+TEST_ADDR(1);
 
 TEST(awdl_peers, init_free) {
 	awdl_peers_t p = awdl_peers_init();
@@ -36,7 +38,7 @@ TEST(awdl_peers, init_free) {
 TEST(awdl_peers, add) {
 	int s;
 	awdl_peers_t p = awdl_peers_init();
-	s = awdl_peer_add(p, &TEST_ADDR, 0, NULL, NULL);
+	s = awdl_peer_add(p, &TEST_ADDR0, 0, NULL, NULL);
 	EXPECT_EQ(s, PEERS_OK);
 	EXPECT_EQ(awdl_peers_length(p), 1);
 	awdl_peers_free(p);
@@ -45,10 +47,10 @@ TEST(awdl_peers, add) {
 TEST(awdl_peers, add_two) {
 	int s;
 	awdl_peers_t p = awdl_peers_init();
-	s = awdl_peer_add(p, &TEST_ADDR, 0, NULL, NULL);
+	s = awdl_peer_add(p, &TEST_ADDR0, 0, NULL, NULL);
 	EXPECT_EQ(s, PEERS_OK);
 	EXPECT_EQ(awdl_peers_length(p), 1);
-	s = awdl_peer_add(p, &TEST_ADDR2, 0, NULL, NULL);
+	s = awdl_peer_add(p, &TEST_ADDR1, 0, NULL, NULL);
 	EXPECT_EQ(s, PEERS_OK);
 	EXPECT_EQ(awdl_peers_length(p), 2);
 	awdl_peers_free(p);
@@ -57,10 +59,10 @@ TEST(awdl_peers, add_two) {
 TEST(awdl_peers, add_same) {
 	int s;
 	awdl_peers_t p = awdl_peers_init();
-	s = awdl_peer_add(p, &TEST_ADDR, 0, NULL, NULL);
+	s = awdl_peer_add(p, &TEST_ADDR0, 0, NULL, NULL);
 	EXPECT_EQ(s, PEERS_OK);
 	EXPECT_EQ(awdl_peers_length(p), 1);
-	s = awdl_peer_add(p, &TEST_ADDR, 0, NULL, NULL);
+	s = awdl_peer_add(p, &TEST_ADDR0, 0, NULL, NULL);
 	EXPECT_EQ(s, PEERS_UPDATE);
 	EXPECT_EQ(awdl_peers_length(p), 1);
 	awdl_peers_free(p);
@@ -69,8 +71,8 @@ TEST(awdl_peers, add_same) {
 TEST(awdl_peers, remove) {
 	int s;
 	awdl_peers_t p = awdl_peers_init();
-	awdl_peer_add(p, &TEST_ADDR, 0, NULL, NULL);
-	s = awdl_peer_remove(p, &TEST_ADDR, NULL, NULL);
+	awdl_peer_add(p, &TEST_ADDR0, 0, NULL, NULL);
+	s = awdl_peer_remove(p, &TEST_ADDR0, NULL, NULL);
 	EXPECT_EQ(s, PEERS_OK);
 	EXPECT_EQ(awdl_peers_length(p), 0);
 	awdl_peers_free(p);
@@ -79,7 +81,7 @@ TEST(awdl_peers, remove) {
 TEST(awdl_peers, remove_empty) {
 	int s;
 	awdl_peers_t p = awdl_peers_init();
-	s = awdl_peer_remove(p, &TEST_ADDR, NULL, NULL);
+	s = awdl_peer_remove(p, &TEST_ADDR0, NULL, NULL);
 	EXPECT_EQ(s, PEERS_MISSING);
 	EXPECT_EQ(awdl_peers_length(p), 0);
 	awdl_peers_free(p);
@@ -88,9 +90,9 @@ TEST(awdl_peers, remove_empty) {
 TEST(awdl_peers, remove_twice) {
 	int s;
 	awdl_peers_t p = awdl_peers_init();
-	awdl_peer_add(p, &TEST_ADDR, 0, NULL, NULL);
-	awdl_peer_remove(p, &TEST_ADDR, NULL, NULL);
-	s = awdl_peer_remove(p, &TEST_ADDR, NULL, NULL);
+	awdl_peer_add(p, &TEST_ADDR0, 0, NULL, NULL);
+	awdl_peer_remove(p, &TEST_ADDR0, NULL, NULL);
+	s = awdl_peer_remove(p, &TEST_ADDR0, NULL, NULL);
 	EXPECT_EQ(s, PEERS_MISSING);
 	EXPECT_EQ(awdl_peers_length(p), 0);
 	awdl_peers_free(p);
@@ -101,15 +103,15 @@ static int count_cb = 0;
 static void test_cb(struct awdl_peer *p, void *ignore) {
 	(void) ignore;
 	count_cb++;
-	EXPECT_TRUE(!memcmp(&TEST_ADDR, &p->addr, sizeof(struct ether_addr)));
+	EXPECT_TRUE(!memcmp(&TEST_ADDR0, &p->addr, sizeof(struct ether_addr)));
 }
 
 TEST(awdl_peers, remove_timedout) {
 	struct awdl_peer *peer = NULL;
 	uint64_t now = 0;
 	awdl_peers_t p = awdl_peers_init();
-	awdl_peer_add(p, &TEST_ADDR, now, NULL, NULL);
-	awdl_peer_get(p, &TEST_ADDR, &peer);
+	awdl_peer_add(p, &TEST_ADDR0, now, NULL, NULL);
+	awdl_peer_get(p, &TEST_ADDR0, &peer);
 	peer->is_valid = 1;
 	EXPECT_EQ(awdl_peers_length(p), 1);
 	awdl_peers_remove(p, now, test_cb, NULL);
@@ -121,3 +123,25 @@ TEST(awdl_peers, remove_timedout) {
 	EXPECT_EQ(count_cb, 1);
 	awdl_peers_free(p);
 }
+
+TEST(awdl_peers, print) {
+	char buf[1000]; // Buffer is large enough
+	awdl_peers_t p = awdl_peers_init();
+	awdl_peer_add(p, &TEST_ADDR0, 0, NULL, NULL);
+	awdl_peer_add(p, &TEST_ADDR1, 0, NULL, NULL);
+	int len = awdl_peers_print(p, buf, sizeof(buf));
+	EXPECT_EQ(len, strlen(buf));
+	EXPECT_STREQ(buf, "<UNNAMED>: 0:0:0:0:0:0 (met 60, ctr 0)\n"
+	                  "<UNNAMED>: 1:1:1:1:1:1 (met 60, ctr 0)\n");
+}
+
+TEST(awdl_peers, print_overflow) {
+	char buf[30]; // Buffer is too small
+	awdl_peers_t p = awdl_peers_init();
+	awdl_peer_add(p, &TEST_ADDR0, 0, NULL, NULL);
+	awdl_peer_add(p, &TEST_ADDR1, 0, NULL, NULL);
+	int len = awdl_peers_print(p, buf, sizeof(buf));
+	EXPECT_GT(len, strlen(buf)); // would have written more
+	EXPECT_EQ(strlen(buf), sizeof(buf) - 1); // buffer is full
+    EXPECT_STREQ(buf, "<UNNAMED>: 0:0:0:0:0:0 (met 6");
+}