PHP FFI Thread Safe patch

ffi.patch

diff --git a/ext/ffi/ffi.c b/ext/ffi/ffi.c
index 9be5ac3405..81ac091750 100644
--- a/ext/ffi/ffi.c
+++ b/ext/ffi/ffi.c
@@ -922,9 +922,11 @@ static void zend_ffi_callback_hash_dtor(zval *zv) /* {{{ */
 }
 /* }}} */
 
-static void zend_ffi_callback_trampoline(ffi_cif* cif, void* ret, void** args, void* data) /* {{{ */
-{
-	zend_ffi_callback_data *callback_data = (zend_ffi_callback_data*)data;
+static void (*orig_interrupt_function)(zend_execute_data *execute_data);
+
+static void zend_ffi_interrupt_function(zend_execute_data *execute_data){
+	
+	zend_ffi_callback_data *callback_data = FFI_G(callback_data).data;
 	zend_fcall_info fci;
 	zend_ffi_type *ret_type;
 	zval retval;
@@ -938,13 +940,14 @@ static void zend_ffi_callback_trampoline(ffi_cif* cif, void* ret, void** args, v
 	fci.param_count = callback_data->arg_count;
 	fci.named_params = NULL;
 
+
 	if (callback_data->type->func.args) {
 		int n = 0;
 		zend_ffi_type *arg_type;
 
 		ZEND_HASH_PACKED_FOREACH_PTR(callback_data->type->func.args, arg_type) {
 			arg_type = ZEND_FFI_TYPE(arg_type);
-			zend_ffi_cdata_to_zval(NULL, args[n], arg_type, BP_VAR_R, &fci.params[n], (zend_ffi_flags)(arg_type->attr & ZEND_FFI_ATTR_CONST), 0, 0);
+			zend_ffi_cdata_to_zval(NULL, FFI_G(callback_data).args[n], arg_type, BP_VAR_R, &fci.params[n], (zend_ffi_flags)(arg_type->attr & ZEND_FFI_ATTR_CONST), 0, 0);
 			n++;
 		} ZEND_HASH_FOREACH_END();
 	}
@@ -969,10 +972,40 @@ static void zend_ffi_callback_trampoline(ffi_cif* cif, void* ret, void** args, v
 
 	ret_type = ZEND_FFI_TYPE(callback_data->type->func.ret_type);
 	if (ret_type->kind != ZEND_FFI_TYPE_VOID) {
-		zend_ffi_zval_to_cdata(ret, ret_type, &retval);
+		zend_ffi_zval_to_cdata(FFI_G(callback_data).ret, ret_type, &retval);
 	}
 
 	zval_ptr_dtor(&retval);
+
+	if (orig_interrupt_function) {
+		orig_interrupt_function(execute_data);
+	}
+	zend_interrupt_function = orig_interrupt_function;
+
+	pthread_cond_signal(&FFI_G(vm_ack));
+	pthread_mutex_unlock(&FFI_G(vm_lock));
+}
+
+static void zend_ffi_callback_trampoline(ffi_cif* cif, void* ret, void** args, void* data) /* {{{ */
+{
+	// get lock, first
+	pthread_mutex_lock(&FFI_G(vm_lock));
+	zend_ffi_call_data call_data = {
+		.cif = cif,
+		.ret = ret,
+		.args = args,
+		.data = (zend_ffi_call_data *)data
+	};
+	FFI_G(callback_data) = call_data;
+	
+	/** post interrupt request */
+	orig_interrupt_function = zend_interrupt_function;
+	zend_interrupt_function = zend_ffi_interrupt_function;
+	zend_atomic_bool_store_ex(&EG(vm_interrupt), true);
+
+	pthread_mutex_lock(&FFI_G(vm_lock));
+	pthread_cond_wait(&FFI_G(vm_ack), &FFI_G(vm_lock));
+	pthread_mutex_unlock(&FFI_G(vm_lock));
 }
 /* }}} */
 
@@ -5447,6 +5480,9 @@ ZEND_MINIT_FUNCTION(ffi)
 		return zend_ffi_preload(FFI_G(preload));
 	}
 
+	pthread_mutex_init(&FFI_G(vm_lock), NULL);
+	pthread_cond_init(&FFI_G(vm_ack), NULL);
+
 	return SUCCESS;
 }
 /* }}} */
diff --git a/ext/ffi/php_ffi.h b/ext/ffi/php_ffi.h
index 02a241c6bb..e8f7f39b67 100644
--- a/ext/ffi/php_ffi.h
+++ b/ext/ffi/php_ffi.h
@@ -17,6 +17,9 @@
 #ifndef PHP_FFI_H
 #define PHP_FFI_H
 
+#include <ffi.h>
+#include <pthread.h>
+
 extern zend_module_entry ffi_module_entry;
 #define phpext_ffi_ptr &ffi_module_entry
 
@@ -27,6 +30,15 @@ typedef enum _zend_ffi_api_restriction {
 } zend_ffi_api_restriction;
 
 typedef struct _zend_ffi_type  zend_ffi_type;
+typedef struct _zend_ffi_callback_data zend_ffi_callback_data;
+
+
+typedef struct _zend_ffi_call_data {
+	ffi_cif* cif;
+	void* ret;
+	void** args;
+	zend_ffi_callback_data* data;
+} zend_ffi_call_data;
 
 ZEND_BEGIN_MODULE_GLOBALS(ffi)
 	zend_ffi_api_restriction restriction;
@@ -35,6 +47,10 @@ ZEND_BEGIN_MODULE_GLOBALS(ffi)
 	/* predefined ffi_types */
 	HashTable types;
 
+	pthread_mutex_t vm_lock;
+	pthread_cond_t vm_ack;
+	zend_ffi_call_data callback_data;
+
 	/* preloading */
 	char *preload;
 	HashTable *scopes;           /* list of preloaded scopes */

test.c

#include <pthread.h>
#include <stdint.h>

typedef int (*callback_t)(int);
typedef void *(*__start_routine)(void *);

void make_thread(callback_t cb, int arg){
	pthread_t tid;
	pthread_create(&tid, NULL, (__start_routine)cb, (void *)(uintptr_t)(arg));
	pthread_detach(tid);
}

test.php

<?php
$ffi = FFI::cdef(
	'void make_thread(int (*cb)(void *), int arg);',
	'./libtest.so'
);

$cb_func = function($arg){
	print("hi from thread\n");
	return 0;
};

for($i=0; $i<2000; $i++){
	$ffi->make_thread($cb_func, 0xBEEF);
}
print("-- survived\n");
sleep(100);