Index: lib/sanitizer_common/sanitizer_common_interceptors.inc
===================================================================
--- lib/sanitizer_common/sanitizer_common_interceptors.inc
+++ lib/sanitizer_common/sanitizer_common_interceptors.inc
@@ -2157,6 +2157,14 @@
 #endif
 
 #if SANITIZER_INTERCEPT_READDIR
+// On FreeBSD opendir() relies on strlen() so we have to intercept it.
+INTERCEPTOR(__sanitizer_dirent *, opendir, const char *filename) {
+  void *ctx;
+  COMMON_INTERCEPTOR_ENTER(ctx, opendir, filename);
+  COMMON_INTERCEPTOR_READ_RANGE(ctx, filename, REAL(strlen)(filename) + 1);
+  return REAL(opendir)(filename);
+}
+
 INTERCEPTOR(__sanitizer_dirent *, readdir, void *dirp) {
   void *ctx;
   COMMON_INTERCEPTOR_ENTER(ctx, readdir, dirp);
@@ -2185,6 +2193,7 @@
 }
 
 #define INIT_READDIR                  \
+  COMMON_INTERCEPT_FUNCTION(opendir); \
   COMMON_INTERCEPT_FUNCTION(readdir); \
   COMMON_INTERCEPT_FUNCTION(readdir_r);
 #else