Re: Segfault when assigning a reference variable

Your extension will have its own peculiarities anyway, just because PHP itself is responsible for memory management as opposed to C/C++. Generally, a PHP extension can't have exactly the same API as a C/C++ library. (Especially, if it performs some kind of memory management.) I suppose you'll provide some docs for the extension. I guess a user will refer to _your_ docs, not the wxWidgets's C++ API. Then I can't find any purpose for making exact copy of C++ API here in PHP. On Sat, 08 Mar 2014 14:33:30 +0100 Johannes Schlüter <johannes@schlueters.de> wrote: > 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 > > > -- Ruslan Osmanov