php扩展实践zend_execute_ex层获取实参

其实在实现的 php 函数里面是很容易获取到的，参考 php 的 builtin 函数 func_get_args() 就可以知道了。

void **p;
int arg_count;
int i;
zend_execute_data *ex = EG(current_execute_data);

if (!ex || !ex->function_state.arguments) {
    RETURN_FALSE;
}

p = ex->function_state.arguments;
arg_count = (int)(zend_uintptr_t) *p;

for (i = 0; i < arg_count; i++) {
    zval *element, *arg;
    arg = *((zval **) (p - (arg_count - i)));
    php_var_dump(&arg, 1 TSRMLS_CC);
}

但是在 zend_execute_ex 中，是不能使用 function_state.arguments 来获取参数的，需要从 argument_stack 中获取调用函数的实参。

static void (*old_zend_execute_ex) (zend_execute_data *execute_data TSRMLS_DC);

ZEND_API void learn_execute_ex (zend_execute_data *execute_data TSRMLS_DC)
{
    php_printf("====== extension debug start ======\n");
    php_printf("function name: %s\n", get_active_function_name(TSRMLS_C));

    old_zend_execute_ex(execute_data TSRMLS_CC);

    int stacked = 0;
    void **top;
    void **bottom;
    zval *arguments;
    smart_str buf = {0};

    array_init(arguments);
    
    top = zend_vm_stack_top(TSRMLS_C) - 1;
    if (top) {
        stacked = (int)(zend_uintptr_t) *top; // argc
        if (stacked) {
            bottom = zend_vm_stack_top(TSRMLS_C);
            EG(argument_stack)->top = top + 1;
            if (zend_copy_parameters_array(stacked, arguments TSRMLS_CC) == SUCCESS) {
                php_json_encode(&buf, arguments, 0 TSRMLS_CC);
            }
            EG(argument_stack)->top = bottom;
        }
    }

    smart_str_0(&buf);

    php_printf("%s\n", buf.c);

    smart_str_free(&buf);
    zval_dtor(arguments);

    php_printf("====== extension debug end ======\n");
}

PHP_MINIT_FUNCTION(learn)
{
    old_zend_execute_ex = zend_execute_ex;
    zend_execute_ex = learn_execute_ex;

    return SUCCESS;
}

PHP_MSHUTDOWN_FUNCTION(learn)
{
    zend_execute_ex = old_zend_execute_ex;

    return SUCCESS;
}

2015-11-04 00:38 更新

后来看到，其实不用上面这中方法就可以实现, php 5.5之后要从 prev 里面去取

/**
 * php_var_dump defined in this head file.
 */
#include "ext/standard/php_var.h"

zend_execute_data *real_execute_data = execute_data->prev_execute_data;

void **p = real_execute_data->function_state.arguments;
int arg_count = (int) (zend_uintptr_t) * p;
zval *argument_element;
int i;
// zval *obj = real_execute_data->object;
unsigned long start = mach_absolute_time();
for (i = 0; i < arg_count; i++) {
    argument_element = *(p - (arg_count - i));
    php_var_dump(&argument_element, 1);
}