On Mon, 16 Jan 2012 15:18:37 -0200
Luiz Capitulino <lcapitul...@redhat.com> wrote:
> On Mon, 16 Jan 2012 17:13:39 +0000
> "Daniel P. Berrange" <berra...@redhat.com> wrote:
>
> > On Mon, Jan 16, 2012 at 03:08:53PM -0200, Luiz Capitulino wrote:
> > > On Fri, 13 Jan 2012 14:48:04 -0700
> > > Eric Blake <ebl...@redhat.com> wrote:
> > >
> > > > > +
> > > > > + pid = fork();
> > > > > + if (!pid) {
> > > > > + char buf[32];
> > > > > + FILE *sysfile;
> > > > > + const char *arg;
> > > > > + const char *pmutils_bin = "pm-is-supported";
> > > > > +
> > > > > + if (strcmp(mode, "hibernate") == 0) {
> > > >
> > > > Strangely enough, POSIX doesn't include strcmp() in its list of
> > > > async-signal-safe functions (which is what you should be restricting
> > > > yourself to, if qemu-ga is multi-threaded), but in practice, I think
> > > > that is a bug of omission in POSIX, and not something you have to change
> > > > in your code.
> > >
> > > memset() ins't either... sigaction() either, which begins to get
> > > annoying.
> > >
> > > For those familiar with glib: isn't it possible to confirm it's using
> > > threads and/or acquire a global mutex or something?
Misread, sigaction() is there. The ones that aren't are strcmp(), strstr()
and memset(). Interestingly, they are all "string functions".
> >
> > The most that GLib says is
> >
> > "The GLib threading system used to be initialized with g_thread_init().
> > This is no longer necessary. Since version 2.32, the GLib threading
> > system is automatically initialized at the start of your program,
> > and all thread-creation functions and synchronization primitives
> > are available right away.
> >
> > Note that it is not safe to assume that your program has no threads
> > even if you don't call g_thread_new() yourself. GLib and GIO can
> > and will create threads for their own purposes in some cases, such
> > as when using g_unix_signal_source_new() or when using GDBus. "
> >
> > The latter paragraph is rather fuzzy, which is probably intentional.
> > So I think the only safe thing, in order to be future proof wrt later
> > GLib releases, is to just assume you have threads at all times.
>
> Yeah, and we do use GIO in qemu-ga...
>
> Thanks Daniel.
>
> >
> >
> > Daniel
>
