[pulseaudio-discuss] [PATCH] module: Assign the index before calling init()

[Tanu Kaskinen]

On Mon, 2013-04-29 at 16:47 +0200, David Henningsson wrote:
> On 04/29/2013 03:46 PM, Tanu Kaskinen wrote:
> > Any code that runs inside the init() callback sees an invalid module
> > index. Sometimes init() does things that cause hooks to be fired. This
> > means that any code that uses hooks may see an invalid module index.
> > Fix this by assigning the module index before init() is called.
> >
> > There are no known issues in the upstream code base where an invalid
> > module index would be used, but an out-of-tree module
> > (module-murphy-ivi) had a problem with this.
> 
> I guess there could be a point that the module is not seen by the core 
> before it is completely loaded, but I don't mind either way. If it helps 
> you, go ahead (after fixing the comment below).
> 
> >
> > BugLink: https://bugs.freedesktop.org/show_bug.cgi?id=63923
> > ---
> >   src/pulsecore/module.c |    9 ++++++---
> >   1 file changed, 6 insertions(+), 3 deletions(-)
> >
> > diff --git a/src/pulsecore/module.c b/src/pulsecore/module.c
> > index 6f276bb..f30a3ce 100644
> > --- a/src/pulsecore/module.c
> > +++ b/src/pulsecore/module.c
> > @@ -113,14 +113,14 @@ pa_module* pa_module_load(pa_core *c, const char *name, const char *argument) {
> >       m->core = c;
> >       m->unload_requested = FALSE;
> >
> > +    pa_assert_se(pa_idxset_put(c->modules, m, &m->index) >= 0);
> > +    pa_assert(m->index != PA_IDXSET_INVALID);
> > +
> >       if (m->init(m) < 0) {
> >           pa_log_error("Failed to load module \"%s\" (argument: \"%s\"): initialization failed.", name, argument ? argument : "");
> >           goto fail;
> >       }
> >
> > -    pa_assert_se(pa_idxset_put(c->modules, m, &m->index) >= 0);
> > -    pa_assert(m->index != PA_IDXSET_INVALID);
> > -
> >       pa_log_info("Loaded \"%s\" (index: #%u; argument: \"%s\").", m->name, m->index, m->argument ? m->argument : "");
> >
> >       pa_subscription_post(c, PA_SUBSCRIPTION_EVENT_MODULE|PA_SUBSCRIPTION_EVENT_NEW, m->index);
> > @@ -144,6 +144,9 @@ pa_module* pa_module_load(pa_core *c, const char *name, const char *argument) {
> >   fail:
> >
> >       if (m) {
> > +        if (m->index != PA_IDXSET_INVALID)
> > +            pa_idxset_remove_by_index(c->modules, m->index);
> 
> m->index must be initialized to PA_IDXSET_INVALID, for jumps to "fail" 
> before pa_idxset_put to behave correctly.

That's already done by fd22c1 in "next". I would otherwise have merged
these two patches, but I pushed fd22c1 before I became convinced that
it's best to add the module to pa_core.modules before calling init().

-- 
Tanu

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