RE: [PHP-DEV] Problem with ext/libxml RINIT/RSHUTDOWN

Hi, After looking into libxml sources I don't think this should be fixed. The code is right (libxml is thread-safe) and slowdown is really small. Thanks. Dmitry. > -----Original Message----- > From: Marcus Boerger [mailto:helly@php.net] > Sent: Saturday, March 18, 2006 1:57 AM > To: Dmitry Stogov > Cc: 'Wez Furlong'; 'Rob Richards'; internals@lists.php.net > Subject: Re: [PHP-DEV] Problem with ext/libxml RINIT/RSHUTDOWN > > > Hello Dmitry, > > which is the default.... > > however we could for optimization add some configure option > "--i-damn-know-what-the-fuck-i-am-doing" that would setup the > handlers only once. Obviously such a thing can only be used > if nothing else is using libxml2. > > marcus > > Friday, March 17, 2006, 2:58:33 PM, you wrote: > > > BTW: libxml can be compiled with LIBXML_THREAD_ENABLED. > > > Dmitry. > > >> -----Original Message----- > >> From: Wez Furlong [mailto:kingwez@gmail.com] > >> Sent: Friday, March 17, 2006 4:33 PM > >> To: Rob Richards > >> Cc: Dmitry Stogov; internals@lists.php.net > >> Subject: Re: [PHP-DEV] Problem with ext/libxml RINIT/RSHUTDOWN > >> > >> > >> Sounds like a nasty situation. > >> I don't think it's possible to sanely restore the handlers at > >> rshutdown in a threaded build without screwing up the other > >> threads that are currently executing. > >> > >> My suggestion is to not restore the handlers for threaded > >> builds, and if there is a library sharing/abuse issue, then > >> treat it as an installation/configuration problem for the > >> person deploying it (eg: don't do that!). There's not much > >> you can do about that without rewriting libxml2 to not use > >> globals for the callbacks. :-/ > >> > >> --Wez. > >> > >> On 3/17/06, Rob Richards <rrichards@ctindustries.net> wrote: > >> > Dmitry Stogov wrote: > >> > > Hi Wez, > >> > > > >> > > I found a bad code in ext/libxml. > >> > > > >> > > On each request startup/shutdown it changing some libxml > >> callbacks. > >> > > At first this slowdown each request, at second > multi-threaded PHP > >> > > may fail, because different threads may set/clean the > >> same callbacks > >> > > in the same time. > >> > > > >> > > May be it is possible to setup these callbacks forever in > >> > > MINIT/MSHUTDOWN, set some flag (somthing like > >> LIBXML(in_request)) in > >> > > RINIT/RSHUTDOWN, and check it in callbacks. > >> > > > >> > Which ones in particular? > >> > Each of the callbacks being utilized are thread safe. > >> > The reason why they need to be set per request is in > order to play > >> > nice with any other modules that might be loaded and use libxml2. > >> > > >> > for example: prior to how the current callbacks are > >> implemented it was > >> > possible to blow away PHP stream usage by any of the xml > extensions > >> > using mod_perl and its xsl module (could do this whether > or not PHP > >> > was running threaded). There are also many other ways to > screw with > >> > the libxml2 globals and effect PHP extensions based on > >> libxml2 as well > >> > using other modules so the only way to protect them is on each > >> > request. In short putting them into the MINIT/MSHUTDOWN > will open > >> > security holes. > >> > > >> > Rob > >> > > >> > >> > > > > > Best regards, > Marcus > > -- > PHP Internals - PHP Runtime Development Mailing List > To unsubscribe, visit: http://www.php.net/unsub.php > > >