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?
Jan
--
Siemens AG, Corporate Technology, CT RTC ITP SES-DE
Corporate Competence Center Embedded Linux
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