[Alsa-devel] [PATCH] alsa-lib trampolines

[goodbyte]

Hi
I've been having issues with alsa-lib on a linux-grsecurity box
(www.grsecurity.net), since there is a trampoline call - code that is
executed on the stack in alsa-lib. I supply a patch that fixes this
problem, but it's not The Right Way way to do it. My suggestion is to
rewrite alsa-lib so snd_hctl_t::compare can be sent directly to qsort.
Comments?


-- 
Erik Månsson

Bender: Bite my shiny, metal ass!

diff -urN alsa-lib-0.9.0rc5/src/control/hcontrol.c 
alsa-lib-0.9.0rc5.new/src/control/hcontrol.c
--- alsa-lib-0.9.0rc5/src/control/hcontrol.c    2002-03-12 21:14:11.000000000 +0100
+++ alsa-lib-0.9.0rc5.new/src/control/hcontrol.c        2002-10-29 10:07:07.000000000 
++0100
@@ -382,17 +382,20 @@
        return 0;
 }
 
+static snd_hctl_t *compare_hctl;
+static int hctl_compare(const void *a, const void *b) {
+       return compare_hctl->compare(*(const snd_hctl_elem_t * const *) a,
+                            *(const snd_hctl_elem_t * const *) b);
+}
+
 static void snd_hctl_sort(snd_hctl_t *hctl)
 {
        unsigned int k;
-       int compar(const void *a, const void *b) {
-               return hctl->compare(*(const snd_hctl_elem_t * const *) a,
-                                    *(const snd_hctl_elem_t * const *) b);
-       }
        assert(hctl);
        assert(hctl->compare);
        INIT_LIST_HEAD(&hctl->elems);
-       qsort(hctl->pelems, hctl->count, sizeof(*hctl->pelems), compar);
+       compare_hctl = hctl;
+       qsort(hctl->pelems, hctl->count, sizeof(*hctl->pelems), hctl_compare);
        for (k = 0; k < hctl->count; k++)
                list_add_tail(&hctl->pelems[k]->list, &hctl->elems);
 }