Disable agent when opcache is in reset pending state (#988) (#1000)

* Disable agent when opcache is in reset pending state (#988)
* Better handling of tracer state

Author: intuibase

src/ext/lifecycle.c

@@ -625,6 +625,8 @@ void elasticApmRequestInit()
 {
     requestCounter++;
 
+    tracerPhpPartOnRequestInitSetInitialTracerState();
+
     TimePoint requestInitStartTime;
     getCurrentTime( &requestInitStartTime );
 
@@ -652,6 +654,12 @@ void elasticApmRequestInit()
         ELASTIC_APM_SET_RESULT_CODE_AND_GOTO_FAILURE();
     }
 
+    if (detectOpcacheRestartPending()) {
+        ELASTIC_APM_LOG_ERROR("Detected that opcache reset is in a pending state. Instrumentation has been disabled for this request. There may be warnings or errors logged for this request.");
+        resultCode = resultSuccess;
+        goto finally;
+    }
+
     if ( ! config->enabled )
     {
         ELASTIC_APM_LOG_DEBUG( "Not enabled" );

src/ext/tracer_PHP_part.c

@@ -75,17 +75,23 @@ String tracerPhpPartStateToString( TracerPhpPartState value )
 
 static TracerPhpPartState g_tracerPhpPartState = numberOfTracerPhpPartState;
 
-void switchTracerPhpPartStateToFailed( String reason, String dbgCalledFromFunc )
+bool canInvokeTracerPhpPart() {
+    return g_tracerPhpPartState == tracerPhpPartState_after_bootstrap;
+}
+
+// returns true if state was changed or false it was same before
+bool switchTracerPhpPartStateToFailed( String reason, String dbgCalledFromFunc )
 {
     if ( g_tracerPhpPartState == tracerPhpPartState_failed )
     {
-        return;
+        return false;
     }
 
     ELASTIC_APM_LOG_ERROR( "Switching tracer PHP part state to failed; reason: %s, current state: %s, called from %s"
                            , reason, tracerPhpPartStateToString( g_tracerPhpPartState ), dbgCalledFromFunc );
 
     g_tracerPhpPartState = tracerPhpPartState_failed;
+    return true;
 }
 
 ResultCode bootstrapTracerPhpPart( const ConfigSnapshot* config, const TimePoint* requestInitStartTime )
@@ -201,10 +207,12 @@ bool tracerPhpPartInternalFuncCallPreHook( uint32_t interceptRegistrationId, zen
     ZVAL_UNDEF( &interceptRegistrationIdAsZval );
     zval phpPartArgs[ g_maxInterceptedCallArgsCount + 2 ];
 
-    if ( g_tracerPhpPartState != tracerPhpPartState_after_bootstrap )
-    {
-        switchTracerPhpPartStateToFailed( /* reason */ "Unexpected current tracer PHP part state", __FUNCTION__ );
-        ELASTIC_APM_SET_RESULT_CODE_AND_GOTO_FAILURE();
+    if (!canInvokeTracerPhpPart()) {
+        if (switchTracerPhpPartStateToFailed( /* reason */ "Unexpected current tracer PHP part state", __FUNCTION__ )) {
+            ELASTIC_APM_SET_RESULT_CODE_AND_GOTO_FAILURE();
+        } else {
+            ELASTIC_APM_SET_RESULT_CODE_TO_SUCCESS_AND_GOTO_FINALLY();
+        }
     }
 
     // The first argument to PHP part's interceptedCallPreHook() is $interceptRegistrationId
@@ -260,10 +268,12 @@ void tracerPhpPartInternalFuncCallPostHook( uint32_t dbgInterceptRegistrationId,
     ResultCode resultCode;
     zval phpPartArgs[ 2 ];
 
-    if ( g_tracerPhpPartState != tracerPhpPartState_after_bootstrap )
-    {
-        switchTracerPhpPartStateToFailed( /* reason */ "Unexpected current tracer PHP part state", __FUNCTION__ );
-        ELASTIC_APM_SET_RESULT_CODE_AND_GOTO_FAILURE();
+    if (!canInvokeTracerPhpPart()) {
+        if (switchTracerPhpPartStateToFailed( /* reason */ "Unexpected current tracer PHP part state", __FUNCTION__ )) {
+            ELASTIC_APM_SET_RESULT_CODE_AND_GOTO_FAILURE();
+        } else {
+            ELASTIC_APM_SET_RESULT_CODE_TO_SUCCESS_AND_GOTO_FINALLY();
+        }
     }
 
     // The first argument to PHP part's interceptedCallPostHook() is $hasExitedByException (bool)
@@ -301,10 +311,12 @@ void tracerPhpPartInterceptedCallEmptyMethod()
     zval phpPartDummyArgs[ 1 ];
     ZVAL_UNDEF( &( phpPartDummyArgs[ 0 ] ) );
 
-    if ( g_tracerPhpPartState != tracerPhpPartState_after_bootstrap )
-    {
-        switchTracerPhpPartStateToFailed( /* reason */ "Unexpected current tracer PHP part state", __FUNCTION__ );
-        ELASTIC_APM_SET_RESULT_CODE_AND_GOTO_FAILURE();
+    if (!canInvokeTracerPhpPart()) {
+        if (switchTracerPhpPartStateToFailed( /* reason */ "Unexpected current tracer PHP part state", __FUNCTION__ )) {
+            ELASTIC_APM_SET_RESULT_CODE_AND_GOTO_FAILURE();
+        } else {
+            ELASTIC_APM_SET_RESULT_CODE_TO_SUCCESS_AND_GOTO_FINALLY();
+        }
     }
 
     ELASTIC_APM_CALL_IF_FAILED_GOTO(
@@ -344,18 +356,22 @@ void tracerPhpPartLogArguments( LogLevel logLevel, uint32_t argsCount, zval args
 
 void tracerPhpPartForwardCall( StringView phpFuncName, zend_execute_data* execute_data, /* out */ zval* retVal, String dbgCalledFrom )
 {
-    ResultCode resultCode;
+    ResultCode resultCode = resultFailure;
+    ZVAL_NULL(retVal);
     uint32_t callArgsCount;
     zval callArgs[ g_maxInterceptedCallArgsCount ];
 
     ELASTIC_APM_LOG_TRACE_FUNCTION_ENTRY_MSG( "phpFuncName: %s, dbgCalledFrom: %s", phpFuncName.begin, dbgCalledFrom );
 
-    if ( g_tracerPhpPartState != tracerPhpPartState_after_bootstrap )
-    {
-        switchTracerPhpPartStateToFailed( /* reason */ "Unexpected current tracer PHP part state", __FUNCTION__ );
-        ELASTIC_APM_SET_RESULT_CODE_AND_GOTO_FAILURE();
+    if (!canInvokeTracerPhpPart()) {
+        if (switchTracerPhpPartStateToFailed( /* reason */ "Unexpected current tracer PHP part state", __FUNCTION__ )) {
+            ELASTIC_APM_SET_RESULT_CODE_AND_GOTO_FAILURE();
+        } else {
+            ELASTIC_APM_SET_RESULT_CODE_TO_SUCCESS_AND_GOTO_FINALLY();
+        }
     }
 
+
     getArgsFromZendExecuteData( execute_data, g_maxInterceptedCallArgsCount, &( callArgs[ 0 ] ), &callArgsCount );
     tracerPhpPartLogArguments( logLevel_trace, callArgsCount, callArgs );
 
@@ -385,9 +401,12 @@ void tracerPhpPartAstInstrumentationDirectCall( zend_execute_data* execute_data
     tracerPhpPartForwardCall( ELASTIC_APM_STRING_LITERAL_TO_VIEW( ELASTIC_APM_PHP_PART_AST_INSTRUMENTATION_DIRECT_CALL_FUNC ), execute_data, /* out */ &unusedRetVal, __FUNCTION__ );
 }
 
+void tracerPhpPartOnRequestInitSetInitialTracerState() {
+    g_tracerPhpPartState = tracerPhpPartState_before_bootstrap;
+}
+
 ResultCode tracerPhpPartOnRequestInit( const ConfigSnapshot* config, const TimePoint* requestInitStartTime )
 {
-    g_tracerPhpPartState = tracerPhpPartState_before_bootstrap;
     return bootstrapTracerPhpPart( config, requestInitStartTime );
 }
 

src/ext/tracer_PHP_part.h

@@ -34,3 +34,4 @@ void tracerPhpPartInterceptedCallEmptyMethod();
 
 void tracerPhpPartAstInstrumentationCallPreHook( zend_execute_data* execute_data, zval* return_value );
 void tracerPhpPartAstInstrumentationDirectCall( zend_execute_data* execute_data );
+void tracerPhpPartOnRequestInitSetInitialTracerState();

src/ext/util_for_PHP.c

@@ -274,6 +274,64 @@ bool isPhpRunningAsCliScript()
     return strcmp( sapi_module.name, "cli" ) == 0;
 }
 
+int call_internal_function(zval *object, const char *functionName, zval parameters[], int32_t parametersCount, zval *returnValue) {
+	zval funcName;
+	ZVAL_STRING(&funcName, functionName);
+
+	int result = resultFailure;
+	zend_try {
+#if PHP_VERSION_ID >= 80000
+		result = _call_user_function_impl(object, &funcName, returnValue, parametersCount, parameters, NULL);
+#else
+		result = _call_user_function_ex(object, &funcName, returnValue, parametersCount, parameters, 0);
+#endif
+	} zend_catch {
+        ELASTIC_APM_LOG_ERROR("Call of '%s' failed", functionName);
+	} zend_end_try();
+
+	zval_ptr_dtor(&funcName);
+	return result;
+}
+
+
+bool detectOpcacheRestartPending() {
+    bool opcacheEnabled = isPhpRunningAsCliScript() ? INI_BOOL("opcache.enable_cli") : INI_BOOL("opcache.enable");
+    if (!opcacheEnabled) {
+        return false;
+    }
+    if (EG(function_table) && !zend_hash_str_find_ptr(EG(function_table), ZEND_STRL("opcache_get_status"))) {
+        return false;
+    }
+
+	zval rv;
+    ZVAL_NULL(&rv);
+	zval parameters[1];
+	ZVAL_BOOL(&parameters[0], false);
+
+    int result = call_internal_function(NULL, "opcache_get_status", parameters, 1, &rv);
+    if (result == resultFailure) {
+        zval_ptr_dtor(&rv);
+        return false;
+    }
+
+    if (Z_TYPE(rv) != IS_ARRAY) {
+        zval_ptr_dtor(&rv);
+        return false;
+    }
+
+	zval *restartPending = zend_hash_str_find(Z_ARRVAL(rv), ZEND_STRL("restart_pending"));
+    if (restartPending && Z_TYPE_P(restartPending) == IS_TRUE) {
+        zval_ptr_dtor(&rv);
+        return true;
+    } else if (!restartPending || Z_TYPE_P(restartPending) != IS_FALSE) {
+        ELASTIC_APM_LOG_ERROR("opcache_get_status returned unexpected data ptr: %p t:%d", restartPending, restartPending ? Z_TYPE_P(restartPending) : -1);
+    }
+
+    zval_ptr_dtor(&rv);
+    return false;
+}
+
+
 bool detectOpcachePreload() {
     if (PHP_VERSION_ID < 70400) {
         return false;

src/ext/util_for_PHP.h

@@ -87,6 +87,7 @@ void getArgsFromZendExecuteData( zend_execute_data *execute_data, size_t dstArra
 
 bool isPhpRunningAsCliScript();
 bool detectOpcachePreload();
+bool detectOpcacheRestartPending();
 void enableAccessToServerGlobal();
 
 #define ELASTIC_APM_ZEND_ADD_ASSOC( map, key, valueType, value ) ELASTIC_APM_PP_CONCAT( ELASTIC_APM_PP_CONCAT( add_assoc_, valueType ), _ex)( (map), (key), sizeof( key ) - 1, (value) )