use a different mechanism to validate value retrieved from ZEND_OP_ARRAY_EXTENSION

Author: lavarou

agent/php_rinit.c

@@ -63,9 +63,9 @@ PHP_RINIT_FUNCTION(newrelic) {
   NRPRG(drupal_http_request_depth) = 0;
 #endif
 #else
+  NRPRG(pid) = nr_getpid();
   NRPRG(user_function_wrappers) = nr_vector_create(64, NULL, NULL);
 #endif
-  NRPRG(pid) = nr_getpid();
 
   if ((0 == NR_PHP_PROCESS_GLOBALS(enabled)) || (0 == NRINI(enabled))) {
     return SUCCESS;

agent/php_user_instrument.c

@@ -164,7 +164,13 @@ static inline nruserfn_t* nr_php_wraprec_lookup_get(zend_function* zf) {
   if (NULL != RUN_TIME_CACHE(&zf->op_array)) {
     wraprec = ZEND_OP_ARRAY_EXTENSION(&zf->op_array, NR_PHP_PROCESS_GLOBALS(op_array_extension_handle));
   }
-  if (NULL != wraprec && NRPRG(pid) != wraprec->pid) {
+  if (NULL != wraprec && wraprec->magic != NR_USERFN_T_MAGIC) {
+    if (nrl_should_print(NRL_VERBOSEDEBUG, NRL_INSTRUMENT)) {
+      char* name = nr_php_function_debug_name(zf);
+      nrl_verbosedebug(NRL_INSTRUMENT, "%s - wraprec for {%s} is invalid",
+                       __func__, name);
+      nr_free(name);
+    }
     wraprec = NULL;
   }
   return wraprec;
@@ -346,9 +352,7 @@ static void nr_php_wrap_user_function_internal(nruserfn_t* wraprec TSRMLS_DC) {
 
 nruserfn_t* nr_php_user_wraprec_create(void) {
   nruserfn_t* wr = (nruserfn_t*)nr_zalloc(sizeof(nruserfn_t));
-  /* NRPRG(pid) is set in rinit but it's sometimes needed before rinit,
-  *  i.e. when wraprec is added via INI */
-  wr->pid = (0 != NRPRG(pid) ? NRPRG(pid) : nr_getpid());
+  wr->magic = NR_USERFN_T_MAGIC;
   return wr;
 }
 

agent/php_user_instrument.h

@@ -14,6 +14,7 @@
 #include "php_user_instrument_hashmap_key.h"
 
 struct _nruserfn_t;
+#define NR_USERFN_T_MAGIC 0x6e72757372666e74ULL /* "nrusrfnt" */
 
 /*
  * This is an unused structure that is used to ensure that a bare return won't
@@ -35,6 +36,7 @@ typedef void (*nruserfn_declared_t)(TSRMLS_D);
  * and so the strings must be discarded in nr_php_user_wraprec_destroy;
  */
 typedef struct _nruserfn_t {
+  uint64_t magic; /* memory marker */
   struct _nruserfn_t* next; /* singly linked list next pointer */
 
 #if ZEND_MODULE_API_NO == ZEND_7_4_X_API_NO
@@ -108,7 +110,6 @@ typedef struct _nruserfn_t {
 #if ZEND_MODULE_API_NO >= ZEND_7_4_X_API_NO
   char* wordpress_plugin_theme;
 #endif
-  int pid; /* pid of a process that created this wraprec */
 } nruserfn_t;
 
 #if ZEND_MODULE_API_NO >= ZEND_8_0_X_API_NO