On 10/16/2015 05:57 PM, Jan Kiszka wrote: > On 2015-10-16 17:31, Philippe Gerum wrote: >> On 10/16/2015 05:28 PM, Jan Kiszka wrote: >>> On 2015-10-16 17:22, Philippe Gerum wrote: >>>> On 10/16/2015 04:56 PM, Jan Kiszka wrote: >>>>> On 2015-10-16 16:49, Jan Kiszka wrote: >>>>>> Hi, >>>>>> >>>>>> kill() is currently handled by libcobalt such that PIDs <= 0 are >>>>>> forwarded to Linux and PIDs > 0 are considered to target only Xenomai >>>>>> threads. But what if the user wants to address a regular Linux task from >>>>>> within a Xenomai application? Shouldn't we retry kill via the Linux path >>>>>> if Xenomai's syscall reports ESRCH? >>>>>> >>>>> >>>>> IOW: >>>>> >>>>> diff --git a/lib/cobalt/signal.c b/lib/cobalt/signal.c >>>>> index aac4059..7e03301 100644 >>>>> --- a/lib/cobalt/signal.c >>>>> +++ b/lib/cobalt/signal.c >>>>> @@ -99,6 +99,10 @@ COBALT_IMPL(int, kill, (pid_t pid, int sig)) >>>>> >>>>> ret = XENOMAI_SYSCALL2(sc_cobalt_kill, pid, sig); >>>>> if (ret) { >>>>> + /* Retry with regular kill is no RT target was found. */ >>>>> + if (ret == -ESRCH) >>>>> + return __STD(kill(pid, sig)); >>>>> + >>>>> errno = -ret; >>>>> return -1; >>>>> } >>>>> >>>>> Jan >>>>> >>>> >>>> This may break code that sends signal 0 to detect whether a rt thread >>>> exists (like copperplate does), which is the reason for the lack of >>>> forwarding IIRC. (ret == -ESRCH && sig) would be required to forward >>>> without breaking such assumption. >>> >>> That still breaks POSIX (what if the user wants to test for a non-rt >>> thread, like this is possible under regular Linux?). Can't copperplate >>> be changed to bypass the wrapper? >>> >> >> Probably, yes. >> > > Looking at cluster_probe, I wonder if there is actually a problem. > Doesn't that code also run over mercury? Then kill(pid, 0) also targets > the whole system, not just a set of Xenomai applications.
Over mercury, the whole system is the rt domain. Or do we need > to ensure that the caller is not migrated to Linux needlessly under > cobalt? IOW: can that probing happen under RT constraints? > It does with clusters. In general, no restriction on the calling domain should exist for this low level interface. > The same applies for me to the other users of the kill-based probing > pattern (copperplate/heapobj-pshared.c and copperplate/regd/fs-common.c). > > Jan > -- Philippe. _______________________________________________ Xenomai mailing list Xenomai@xenomai.org http://xenomai.org/mailman/listinfo/xenomai