Re: [PATCH] qga: do not attempt running hwclock(8) on BSD

[Roman Bogorodskiy <bogorodskiy@gmail.com>]

  Brad Smith wrote:

> On 2026-10-14 7:20 a.m., Roman Bogorodskiy wrote:
> > Currently, qmp_guest_set_time() sets system time using
> > the settimeofday(2) system call and then runs the hwclock(8)
> > util to set hardware time.
> > 
> > BSDs do not ship hwclock(8), so current implementation
> > always fails while trying to run it.
> > 
> > Update the code not to run it on BSD. The settimeofday(2)
> > call sets both system and hardware time on these systems.
> > For example, on FreeBSD settimeofday() calls settime()
> > which calls resettodr() [1] which updates RTC clock [2].
> > It is similar on OpenBSD and NetBSD, though implementations
> > differ a bit.
> > 
> > Additional detail: on FreeBSD RTC clock setting can be
> > disabled with the `machdep.disable_rtc_set` sysctl.
> > As we cannot do anything about it, do not handle that
> > case separately.
> > 
> > BSD systems do not provide a common utility equivalent
> > to hwclock -s, so report an unsupported operation when
> > no time is supplied.
> > 
> > 1: https://cgit.freebsd.org/src/tree/sys/kern/kern_time.c
> > 2: https://cgit.freebsd.org/src/tree/sys/kern/subr_rtc.c
> > 
> > Signed-off-by: Roman Bogorodskiy <bogorodskiy@gmail.com>
> > ---
> >   qga/commands-posix.c | 14 ++++++++++++++
> >   1 file changed, 14 insertions(+)
> > 
> > diff --git a/qga/commands-posix.c b/qga/commands-posix.c
> > index 837e285b6d..f3d18e6dcd 100644
> > --- a/qga/commands-posix.c
> > +++ b/qga/commands-posix.c
> > @@ -322,6 +322,20 @@ void qmp_guest_set_time(bool has_time, int64_t time_ns, Error **errp)
> >           }
> >       }
> > +#if defined(CONFIG_BSD)
> > +    /*
> > +     * BSDs (FreeBSD, OpenBSD, NetBSD) do not have the hwclock(8) tool.
> > +     * These systems update hardware clock when settimeofday() sets
> > +     * system time, so no additional actions are needed.
> > +     * Setting system time from RTC is not supported.
> > +     */
> > +    if (!has_time) {
> > +        error_setg(errp, "Setting system time from RTC is not supported");
> > +    }
> > +
> > +    return;
> > +#endif
> > +
> >       /* Now, if user has passed a time to set and the system time is set, we
> >        * just need to synchronize the hardware clock. However, if no time was
> >        * passed, user is requesting the opposite: set the system time from the
> 
> The command is Linux specific so it shouldn't be checking CONFIG_BSD. It
> should be
> using something like #ifndef CONFIG_LINUX.
> 

Updated in v2. Actually, I have started with that, but later changed to
CONFIG_BSD check because I tried to avoid testing this change on
Solaris. Anyway, just tried this change on OpenIndiana and it works as
expected.