From b1e00359ba663d8fd9d931833e162e5a9f604166 Mon Sep 17 00:00:00 2001
From: Dmitry Volyntsev <xeioex@nginx.com>
Date: Mon, 11 Nov 2019 15:37:08 +0300
Subject: [PATCH] Fixed sharing of externals between main and cloned VMs.

The issue was introduced in 7e7d0dac4572.

This closes #245 issue on Github.
---
 src/njs_extern.c         | 17 ++++++++++++++---
 src/test/njs_unit_test.c |  3 +++
 2 files changed, 17 insertions(+), 3 deletions(-)

diff --git a/src/njs_extern.c b/src/njs_extern.c
index af33d7cb..83dc3c53 100644
--- a/src/njs_extern.c
+++ b/src/njs_extern.c
@@ -172,22 +172,33 @@ njs_vm_external_create(njs_vm_t *vm, njs_value_t *ext_val,
     const njs_extern_t *proto, njs_external_ptr_t object)
 {
     void       *obj;
+    uint32_t   n;
     njs_arr_t  *externals;
 
     if (njs_slow_path(proto == NULL)) {
         return NJS_ERROR;
     }
 
-    if (njs_slow_path(vm->external_objects == NULL)) {
-        externals = njs_arr_create(vm->mem_pool, 4, sizeof(void *));
+    if (vm->external_objects->mem_pool != vm->mem_pool) {
+
+        /* Making a local copy of externals in shared VM. */
+
+        n = vm->external_objects->items;
+
+        externals = njs_arr_create(vm->mem_pool, n + 4, sizeof(void *));
         if (njs_slow_path(externals == NULL)) {
             return NJS_ERROR;
         }
 
+        if (n > 0) {
+            memcpy(externals->start, vm->external_objects->start,
+                   n * sizeof(void *));
+            externals->items = n;
+        }
+
         vm->external_objects = externals;
     }
 
-
     obj = njs_arr_add(vm->external_objects);
     if (njs_slow_path(obj == NULL)) {
         return NJS_ERROR;
diff --git a/src/test/njs_unit_test.c b/src/test/njs_unit_test.c
index 5c29adfd..40c86a36 100644
--- a/src/test/njs_unit_test.c
+++ b/src/test/njs_unit_test.c
@@ -14694,6 +14694,9 @@ static njs_unit_test_t  njs_shared_test[] =
 
     { njs_str("isNaN(function(){})"),
       njs_str("true") },
+
+    { njs_str("var r; for (var i = 0; i < 2**10; i++) {r = $r.create('XXX').uri;}"),
+      njs_str("undefined") },
 };
 
 
-- 
2.47.3