Fetch the function return value in PHP extension C++

Question

I have created an php extension in c++ which tracks the call graph of each request(centos7-64 bit,PHP5.6).And now,I want to get the function return value of each function. It can be done by using zend_excute_data structure(original_return_value).

 zend_execute_data *data;
 data = EG(current_execute_data);
 if(data->original_return_value)
 {
        zval *rvalue = *(data->original_return_value);    // crashing here
    switch (Z_TYPE(argument_element))
        {
        ..
        .. 
        ..
    }
 }

Here, while assigning the original_return_value to rvalue,my php extension getting crash. Is this correct way to do? or anything else.

I tried with EG(return_value_ptr_ptr) global also,still i didn't get. — Durai
– Durai, Commented Nov 23, 2018 at 12:42

darune · Accepted Answer · 2018-11-20 13:34:22Z

0

zval *rvalue = *(data->original_return_value);    // crashing here

Its because of the last deref of original_return_value. Either the data object or original_return_value is uninitialized or corrupted memory.

answered Nov 20, 2018 at 13:34

darune

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1 Comment

Durai Over a year ago

The data object has the value.May be original_return_value points the corrupted memory. Other than this,how can i get the function return value?

Durai · Accepted Answer · 2018-11-29 13:36:08Z

0

Finally I got it.

zval **return_value_ptr = &EX_TMP_VAR(execute_data, execute_data->opline->result.var)->var.ptr;

return_value_ptr is has the return value of currently executed function.

answered Nov 29, 2018 at 13:36

Durai

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