diff --git a/src/net.c b/src/net.c
index 4ece161..378f59e 100644
--- a/src/net.c
+++ b/src/net.c
@@ -335,14 +335,17 @@ static int hyper_remove_nic(char *device)
 {
 	char path[256], real[128];
 	int fd;
+	ssize_t size;
 
 	sprintf(path, "/sys/class/net/%s", device);
 
-	if (readlink(path, real, 128) < 0) {
+	size = readlink(path, real, 128);
+	if (size < 0 || size > 127) {
 		perror("fail to read link directory");
 		return -1;
 	}
 
+	real[size] = '\0';
 	sprintf(path, "/sys/%s/../../../remove", real + 5);
 
 	fprintf(stdout, "get net sys path %s\n", path);
@@ -869,7 +872,7 @@ void hyper_cleanup_dns(struct hyper_pod *pod)
 	int fd = open("/tmp/hyper/resolv.conf", O_WRONLY| O_TRUNC);
 
 	if (fd < 0) {
-		perror("open /tmp/resolv.conf failed");
+		perror("open /tmp/hyper/resolv.conf failed");
 		return;
 	}