[RFC v3 04/23] sysdeps/clock_gettime: Use clock_gettime64 if avaliable

Arnd Bergmann arnd@arndb.de
Wed Jul 17 08:04:00 GMT 2019


On Wed, Jul 17, 2019 at 7:39 AM Florian Weimer <fweimer@redhat.com> wrote:
> > diff --git a/nptl/pthread_mutex_timedlock.c b/nptl/pthread_mutex_timedlock.c
> > index 52c258e33d..8d9cae7d87 100644
> > --- a/nptl/pthread_mutex_timedlock.c
> > +++ b/nptl/pthread_mutex_timedlock.c
> > @@ -402,10 +402,17 @@ __pthread_mutex_clocklock_common (pthread_mutex_t *mutex,
> >                   /* Delay the thread until the timeout is reached.
> >                      Then return ETIMEDOUT.  */
> >                   struct timespec reltime;
> > +#ifdef __NR_clock_gettime64
> > +                 struct __timespec64 now;
> > +
> > +                 INTERNAL_SYSCALL (clock_gettime64, __err, 2, CLOCK_REALTIME,
> > +                                   &now);
> > +#else
> >                   struct timespec now;
> >
> >                   INTERNAL_SYSCALL (clock_gettime, __err, 2, clockid,
> >                                     &now);
> > +#endif
> >                   reltime.tv_sec = abstime->tv_sec - now.tv_sec;
> >                   reltime.tv_nsec = abstime->tv_nsec - now.tv_nsec;
> >                   if (reltime.tv_nsec < 0)
>
> I believe this needs to be updated for correctness (truncation of
> tv_sec) if ever ported to architectures where __nanosleep_nocancel takes
> a 32-bit time_t argument.  I don't know what our plans are regarding to
> that.
>
> If you had
>
> #define __NR_clock_gettime64  __NR_clock_gettime
>
> in <sysdep.h>, you wouldn't need this change.

Could it be changed to just call internal __clock_gettime64() and
__nanosleep_nocancel_time64() functions that will then take care
of the architecture specifics like syscall number, vdso and
truncation?

        Arnd



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