| Message ID | 20191214094526.8698-17-cohuck@redhat.com (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
| Series | [PULL,v2,01/16] vfio-ccw: Fix error message | expand |
On Sat, 14 Dec 2019 at 09:46, Cornelia Huck <cohuck@redhat.com> wrote: > > The Posix implementation of guest-set-time invokes hwclock to > set/retrieve the time to/from the hardware clock. If hwclock > is not available, the user is currently informed that "hwclock > failed to set hardware clock to system time", which is quite > misleading. This may happen e.g. on s390x, which has a different > timekeeping concept anyway. > > Let's check for the availability of the hwclock command and > return QERR_UNSUPPORTED for guest-set-time if it is not available. > > Reviewed-by: Laszlo Ersek <lersek@redhat.com> > Reviewed-by: Daniel P. Berrangé <berrange@redhat.com> > Reviewed-by: Michael Roth <mdroth@linux.vnet.ibm.com> > Message-Id: <20191205115350.18713-1-cohuck@redhat.com> > Reviewed-by: Philippe Mathieu-Daudé <philmd@redhat.com> > Signed-off-by: Cornelia Huck <cohuck@redhat.com> > --- > qga/commands-posix.c | 13 ++++++++++++- > 1 file changed, 12 insertions(+), 1 deletion(-) > > diff --git a/qga/commands-posix.c b/qga/commands-posix.c > index 1c1a165daed8..0be301a4ea77 100644 > --- a/qga/commands-posix.c > +++ b/qga/commands-posix.c > @@ -156,6 +156,17 @@ void qmp_guest_set_time(bool has_time, int64_t time_ns, Error **errp) > pid_t pid; > Error *local_err = NULL; > struct timeval tv; > + static const char hwclock_path[] = "/sbin/hwclock"; > + static int hwclock_available = -1; > + > + if (hwclock_available < 0) { > + hwclock_available = (access(hwclock_path, X_OK) == 0); > + } > + > + if (!hwclock_available) { > + error_setg(errp, QERR_UNSUPPORTED); > + return; > + } > > /* If user has passed a time, validate and set it. */ > if (has_time) { > @@ -195,7 +206,7 @@ void qmp_guest_set_time(bool has_time, int64_t time_ns, Error **errp) > > /* Use '/sbin/hwclock -w' to set RTC from the system time, > * or '/sbin/hwclock -s' to set the system time from RTC. */ > - execle("/sbin/hwclock", "hwclock", has_time ? "-w" : "-s", > + execle(hwclock_path, "hwclock", has_time ? "-w" : "-s", > NULL, environ); > _exit(EXIT_FAILURE); > } else if (pid < 0) { > -- FWIW, Coverity thought this might be a time-of-check-time-of-use bug based on our doing an access() check and then later doing an execle(). This seems like a false positive to me, so I've marked it as such (CID 1411029). thanks -- PMM
diff --git a/qga/commands-posix.c b/qga/commands-posix.c index 1c1a165daed8..0be301a4ea77 100644 --- a/qga/commands-posix.c +++ b/qga/commands-posix.c @@ -156,6 +156,17 @@ void qmp_guest_set_time(bool has_time, int64_t time_ns, Error **errp) pid_t pid; Error *local_err = NULL; struct timeval tv; + static const char hwclock_path[] = "/sbin/hwclock"; + static int hwclock_available = -1; + + if (hwclock_available < 0) { + hwclock_available = (access(hwclock_path, X_OK) == 0); + } + + if (!hwclock_available) { + error_setg(errp, QERR_UNSUPPORTED); + return; + } /* If user has passed a time, validate and set it. */ if (has_time) { @@ -195,7 +206,7 @@ void qmp_guest_set_time(bool has_time, int64_t time_ns, Error **errp) /* Use '/sbin/hwclock -w' to set RTC from the system time, * or '/sbin/hwclock -s' to set the system time from RTC. */ - execle("/sbin/hwclock", "hwclock", has_time ? "-w" : "-s", + execle(hwclock_path, "hwclock", has_time ? "-w" : "-s", NULL, environ); _exit(EXIT_FAILURE); } else if (pid < 0) {