add shutdown functions

Author: ZNeumann

agent/php_mysqli.c

@@ -688,3 +688,28 @@ const char* nr_php_mysqli_strip_persistent_prefix(const char* host) {
 
   return host;
 }
+
+void nr_mysqli_rshutdown() {
+  /*
+   * This frees mysqli metadata stored in the transaction.
+   *
+   * `mysqli_queries` contains duplicates of zvals. If
+   * `nr_php_txn_end` is called from the post-deactivate callback, request
+   * shutdown functions have already been called; and the Zend VM has already
+   * forcefully freed all dangling zvals that are not referenced by the global
+   * scope (regardless of their reference count), thus leaving the zvals stored
+   * in the mysqli_queries metadata in an "undefined" state. Consequently,
+   * freeing the zvals in `nr_php_txn_end` at this stage can result in undefined
+   * behavior.
+   *
+   * Calling this function during the RSHUTDOWN phase ensures that the zvals in
+   * `mysqli_queries` are cleaned up before Zend winds down the VM and
+   * forcefully frees zvals.
+   *
+   * If `nr_php_txn_end` is called outside the post-deactivate callback,
+   * it frees `mysqli_queries` by itself.
+   */
+  if (nrlikely(NRPRG(txn))) {
+    nr_hashmap_destroy(&NRTXNGLOBAL(mysqli_queries));
+  }
+}

agent/php_mysqli.h

@@ -163,4 +163,10 @@ extern nr_datastore_instance_t* nr_php_mysqli_retrieve_datastore_instance(
 extern void nr_php_mysqli_remove_datastore_instance(
     const zval* mysqli_obj TSRMLS_DC);
 
+/*
+ * Purpose : Frees reference incremented, transaction global zvals
+ *           that must be cleaned up prior to postdeactivate
+ */
+extern void nr_mysqli_rshutdown();
+
 #endif /* PHP_MYSQLI_HDR */

agent/php_pdo.c

@@ -642,3 +642,28 @@ zval* nr_php_pdo_disable_persistence(const zval* options TSRMLS_DC) {
   nr_php_zval_free(&persistent);
   return result;
 }
+
+void nr_pdo_rshutdown() {
+  /*
+   * This frees pdo metadata stored in the transaction.
+   *
+   * `pdo_link_options` contains duplicates of zvals. If
+   * `nr_php_txn_end` is called from the post-deactivate callback, request
+   * shutdown functions have already been called; and the Zend VM has already
+   * forcefully freed all dangling zvals that are not referenced by the global
+   * scope (regardless of their reference count), thus leaving the zvals stored
+   * in the pdo_link_options metadata in an "undefined" state. Consequently,
+   * freeing the zvals in `nr_php_txn_end` at this stage can result in undefined
+   * behavior.
+   *
+   * Calling this function during the RSHUTDOWN phase ensures that the zvals in
+   * `pdo_link_options` are cleaned up before Zend winds down the VM and
+   * forcefully frees zvals.
+   *
+   * If `nr_php_txn_end` is called outside the post-deactivate callback,
+   * it frees `pdo_link_options` by itself.
+   */
+  if (nrlikely(NRPRG(txn))) {
+    nr_hashmap_destroy(&NRTXNGLOBAL(pdo_link_options));
+  }
+}

agent/php_pdo.h

@@ -161,4 +161,9 @@ extern nr_status_t nr_php_pdo_parse_data_source(
 extern void nr_php_pdo_free_data_sources(struct pdo_data_src_parser* parsed,
                                          size_t nparams);
 
+/*
+ * Purpose : Frees reference incremented, transaction global zvals
+ *           that must be cleaned up prior to postdeactivate
+ */
+extern void nr_pdo_rshutdown();
 #endif

agent/php_rshutdown.c

@@ -49,6 +49,8 @@ PHP_RSHUTDOWN_FUNCTION(newrelic) {
 
   nr_guzzle4_rshutdown(TSRMLS_C);
   nr_curl_rshutdown(TSRMLS_C);
+  nr_pdo_rshutdown();
+  nr_mysqli_rshutdown();
 
   nrl_verbosedebug(NRL_INIT, "RSHUTDOWN processing done");