[xine-devel] calling mediamark_duplicate_alternates when mmk->alternates is NULL

[Stephen t. <st...@to...>]

==20234== Conditional jump or move depends on uninitialised value(s)
==20234==    at 0x806F7FA: mediamark_duplicate_alternates
(mediamark.c:250)
==20234==    by 0x805342F: gui_set_current_mmk (actions.c:1571)
==20234==    by 0x807C5E9: mrl_play (mrl_browser.c:437)
==20234==    by 0x80CDACF: mrlbrowser_select_mrl (mrlbrowser.c:843)

Looking at line 250 there is a problem that s_mmk->alternates is not
intialized. I agree that the intent of this is to say if the any of
these pointers are not set we do not do the "if" statement.

gdb) list
245           mmk->alternates = alt;
246
247       }
248     }
249     void mediamark_duplicate_alternates(mediamark_t *s_mmk,
mediamark_t *d_mmk) {
250       if(s_mmk && s_mmk->alternates && d_mmk) {
251         alternate_t *alt;
252
253         if((alt = s_mmk->alternates)) {
254           alternate_t *c_alt, *p_alt = NULL, *t_alt = NULL;

(gdb) print s_mmk
$1 = (mediamark_t *) 0x52bf9200

(gdb) print s_mmk->alternates
$2 = (alternate_t *) 0x0

(gdb) print d_mmk
$3 = (mediamark_t *) 0x1beab3c8

(gdb) info thread
(gdb) bt
#0  0x0806f7fa in mediamark_duplicate_alternates (s_mmk=0x52bf9200,
d_mmk=0x1beab3c8)
    at mediamark.c:250
#1  0x08053430 in gui_set_current_mmk (mmk=0x52bf9200) at actions.c:1571
#2  0x0807c5ea in mrl_play (w=0x0, data=0x8, mrl=0x1cd33e98) at
mrl_browser.c:437
#3  0x080cdad0 in mrlbrowser_select_mrl (private_data=0x208c5e78, j=8,
add_callback=0,
    play_callback=1) at mrlbrowser.c:843
#4  0x080cdb96 in mrlbrowser_play (w=0x1bed0f10, data=0x208c5e78) at
mrlbrowser.c:868
#5  0x080b1efc in notify_click_button (w=0x1bed0f10, button=1, bUp=1,
x=53, y=225) at button.c:184
#6  0x080b1fc2 in notify_event (w=0x1bed0f10, event=0x52bfa440,
result=0x52bfa438) at button.c:217
#7  0x080d6b94 in xitk_click_notify_widget_list (wl=0x1bf57400, x=53,
y=225, button=1, bUp=1)
    at widget.c:1100
#8  0x080e06d7 in xitk_xevent_notify (event=0x52bfa920) at xitk.c:1560
#9  0x080e1509 in xitk_run (cb=0x805b781 <on_start>, data=0x52bfbad8) at
xitk.c:1868
#10 0x0805bd6d in gui_run (session_opts=0x0) at event.c:1778
#11 0x0806f021 in main (argc=1, argv=0x52bfdeb4) at main.c:2276

In the code in actions.c at line 1562 we check to see if mmk is set that
we copy the values of mmk into gGui->mmk. Well we copy the
mmk->got_alternate value to gGui->mmk.got_alternate. What happens if
that is set to 0 why do we then call mediamark_duplicate_alternates
(mmk, &(gGui->mmk))?

By the way what are the acceptable values of mediamark_t got_alternate
integer?

-------- WORKAROUND ---------
action.c: after line 1570

    if (mmk->got_alternate == 1)
      {
        mediamark_duplicate_alternates(mmk, &(gGui->mmk));
      }
    else
      {
        gGui->mmk.alternates    = NULL;
        gGui->mmk.cur_alt       = NULL;
      }

Stephen
-- 
Email: st...@to...