Re: Segfault when assigning a reference variable

On Fri, 2014-03-07 at 16:16 -0400, JGM wrote: > I'm emulating the same behavior of wxWidgets since the code is being auto > generated and I want to keep compatibility as much as possible with how > wxWidgets works so people that comes from C++ world can use the extension > with the same knowledge as that of original implementation. wxPHP is almost > a 1 on 1 binding except for wxString which is a native php string and > wxDateTime which is just a timestamp on wxphp. Still PHP is a different language with other paradigms. See fread(): PHP for asic functions is a wrapper over C, by reading a C manual you can grasps many parts of PHP but still fread() uses a slightly different way. > It is strange that the first call works and assings the buffer reference > properly but second call fails. I haven't fully checked, but the suspicious part for me is ZVAL_STRING(arguments[0], (char*) buffer, 0); I assume that on $buffer = fread($this->image, $bufsize); $buffer tries to free its contents in order to be overwritten, but the buffer passed to wxInputStream_php::OnSysRead may not be freed by PHP. I assume simply passing a NULL zval to the function would be enough. Some other unrelated notes on things I saw: You are calling zend_call_function(). this is no ZEND_API so depending on compiler flags etc. it is not exported and not callable from the extensions .so/.dll file. The usage of static bool is_php_user_space_implemented is suspicious. Is there never a chance that the method at first does not exist and a user provides it lateron? In memcpy ((void*) buffer, (void*) Z_STRVAL_P(arguments[0]), Z_STRLEN_P(arguments[0])); you assume that the arguments[0] zval will still be a string, if it is passed y ref this is not guaranteed. The user might do $buffer = NULL; (or an object with a __toString()). Also you don't verify that the buffer is large enough (the user might ignore $bufsize). In return (size_t) Z_LVAL_P(return_value); you aren't verifying the type either. If the user by mistake returns a string with the contents this will misbehave. You also don't check whether the returned length matches the information from the return value. Thus the consumer of wxInputStream_php::OnSysRead can't rely on that size. johannes