On 03.03.2026 11:50, Teddy Astie wrote:
> Le 02/03/2026 à 17:52, Jan Beulich a écrit :
>> On 27.02.2026 18:00, Teddy Astie wrote:
>>> @@ -1354,6 +1358,127 @@ void enable_turbo_mode(int argc, char *argv[])
>>> errno, strerror(errno));
>>> }
>>>
>>> +static int fetch_dts_temp(xc_interface *xch, uint32_t cpu, bool package,
>>> int *temp)
>>> +{
>>> + xc_resource_entry_t entries[] = {
>>> + { .idx = package ? MSR_PACKAGE_THERM_STATUS :
>>> MSR_IA32_THERM_STATUS },
>>> + { .idx = MSR_TEMPERATURE_TARGET },
>>> + };
>>> + struct xc_resource_op ops = {
>>> + .cpu = cpu,
>>> + .entries = entries,
>>> + .nr_entries = ARRAY_SIZE(entries),
>>> + };
>>> + int tjmax;
>>> +
>>> + int ret = xc_resource_op(xch, 1, &ops);
>>> +
>>> + switch ( ret )
>>> + {
>>> + case 0:
>>> + /* This CPU isn't online or can't query this MSR */
>>> + return -1;
>>
>> Further down at the callers of this function you assume errno is set whenever
>> an error indication is returned. As xc_resource_op() didn't fail, you will
>> need to synthesize an errno value here.
>>
>
> ah yes indeed
>
>>> +static void get_core_temp(int argc, char *argv[])
>>> +{
>>> + int temp = -1, cpu = -1;
>>> + unsigned int socket;
>>> + bool has_data = false;
>>> +
>>> + if ( argc > 0 )
>>> + parse_cpuid(argv[0], &cpu);
>>> +
>>> + if ( cpu != -1 )
>>> + {
>>> + if ( !fetch_dts_temp(xc_handle, cpu, false, &temp) )
>>> + printf("CPU%d: %d°C\n", cpu, temp);
>>> + else
>>> + {
>>> + fprintf(stderr, "Unable to fetch temperature (%d - %s)\n",
>>> + errno, strerror(errno));
>>> + printf("No data\n");
>>> + exit(ENODATA);
>>
>> In how far is using errno values as arguments to exit() a useful thing? (I
>> think you had it like this before, and I merely forgot to ask.) Yes, I can
>> see the tool using a number of exit(EINVAL), but I don't understand those
>> either. This way you can't even document easily what particular exit codes
>> mean, as the errno values may vary across OSes.
>>
>
> I reused the exit(...) pattern used in xenpm, but I'm also fine by
> returning simpler errors (like exit(1) or exit(EXIT_FAILURE)).
Anthony, can you please suggest which one better fits the toolstack as a
whole?
Jan
