RE: [PHP-DEV] Memory leak and possible cause of bug #15333

Gotcha. Guess I missed that there was another copy somewhere. I'm trying to track down a problem with ISAPI that causes php to die and take down everything with it. Thought I might have a handle on it. Thanks for the clarification. Joseph > -----Original Message----- > From: brad lafountain [mailto:rodif_bl@yahoo.com] > Sent: Monday, April 08, 2002 4:25 PM > To: Joseph Tate; Php-Dev List > Subject: RE: [PHP-DEV] Memory leak and possible cause of bug #15333 > > > hmm > ok > > zend_constant *c, *b; > char *sname = "myname"; > > c->name = name; // the c->name is just a pointer to the sname > //c->name = strdup(sname); // c->name would have it's own memory > > b = c; //now b->name points to sname > > free(b->name); // would try and free b->name which can't be done, > segfault! > > so now you do this: > > zend_constant *c, *b; > char *sname = "myname"; > c->name = strdup(sname); // c->name would have it's own memory > > b = c; //now b->name points to a copy of sname > copy_zend_constant(b); //now b->name has its own memory > > free(b->name); // now this will work no segfaults here > > and if you look where copy_zend_constant it is only called when > you want to > copy constants from one hash to another. > > > - Brad > --- Joseph Tate <jtate@mi-corporation.com> wrote: > > I don't follow you. Why does it need to be copied? c->name already > > contains the value. Old? New? c is c is c. Commenting out the code > > causes other problems elsewhere (or seems to). I just don't > understand why > > it has to be done. > > > > > -----Original Message----- > > > --- Joseph Tate <jtate@mi-corporation.com> wrote: > > > > in the copy_zend_constant function it reads: > > > > > > > > void copy_zend_constant(zend_constant *c) > > > > { > > > > c->name = zend_strndup(c->name, c->name_len); > > > > if (!(c->flags & CONST_PERSISTENT)) { > > > > zval_copy_ctor(&c->value); > > > > if (c->flags & CONST_EFREE_PERSISTENT) { /* > > > persist_alloc()'d data */ > > > > persist_alloc(&c->value); > > > > } > > > > } > > > > } > > > > > > > > I draw your attention to the first line in the function: > > > > c->name = zend_strndup(c->name, c->name_len); > > > > > > > > First of all, why is this string duplicated only to store > it to the same > > > > location? Secondly, is c->name freed somewhere else? Cause I > > > can't see it > > > > being freed. Seems like this line can be removed... > > > > > > > > > > So c points to the "old" value and you need to copy the name and > > > the value to > > > the "new" one, name and value. and the way hashes and emalloc > > > works the memory > > > will be freed automatically. > > > > > > > > > > > __________________________________________________ > Do You Yahoo!? > Yahoo! Tax Center - online filing with TurboTax > http://taxes.yahoo.com/ > > -- > PHP Development Mailing List <http://www.php.net/> > To unsubscribe, visit: http://www.php.net/unsub.php