[ltt-dev] [UST PATCH] Fix libustctl_function_tests

[Nils Carlson]

On Wed, 23 Feb 2011, Mathieu Desnoyers wrote:

> * Nils Carlson (nils.carlson at ericsson.com) wrote:
>> On Wed, 23 Feb 2011, Yannick Brosseau wrote:
>>
>>> After discussions, we concluded that the enable a non existing marker is a valid case, so we
>>> move it to the working case section.
>>> While being there, check that the re-enable a marker set the right errno
>>>
>>
>> I don't really understand your reasoning. This is a question of libust
>> being broken and the test-case showing this. We should fix the test-case.
>> It should not be possible to enable a non-existent marker, the function
>> should return -1, not 0 as it currently does.
>
> Enabling a non-existent marker/tracepoint is a perfectly valid case. If
> the application later on loads a library with dlopen that contains this
> marker, it should be enabled as soon as the library is loaded. So this
> requires that the user can ask for enabling markers that do not appear
> in the marker list yet. I do that to handle module loading in LTTng
> (kernel).

Ok. So we can pre-activate a marker... Interesting. Then I agree we can 
change the test-case. Though maybe somebody should document this as it 
doesn't make a lot of sense unless you consider the library case. Also, 
I'm not really sure I like it. If a user expects a marker to be there
and the marker isn't it feels silly not to give any feedback. I could see 
a lot of users expecting ust to complain when you activate non-existent 
markers, following the rule of least-suprise I think that it should 
complain.

Have you considered adding a parameter for this? Like a FORCE_ACTIVATE 
flag or something?

/Nils

> Thanks,
>
> Mathieu
>
>>
>> /Nils
>>
>>> Signed-off-by: Yannick Brosseau <yannick.brosseau at gmail.com>
>>> ---
>>> .../libustctl_function_tests.c                     |   10 ++++++----
>>> 1 files changed, 6 insertions(+), 4 deletions(-)
>>>
>>> diff --git a/tests/libustctl_function_tests/libustctl_function_tests.c b/tests/libustctl_function_tests/libustctl_function_tests.c
>>> index 947028f..7c12695 100644
>>> --- a/tests/libustctl_function_tests/libustctl_function_tests.c
>>> +++ b/tests/libustctl_function_tests/libustctl_function_tests.c
>>> @@ -21,6 +21,7 @@
>>> #include <unistd.h>
>>> #include <sys/types.h>
>>> #include <sys/wait.h>
>>> +#include <errno.h>
>>>
>>> #include <ust/marker.h>
>>> #include <ust/ustctl.h>
>>> @@ -136,15 +137,16 @@ static void ustctl_function_tests(pid_t pid)
>>>
>>> 	tap_ok(!ustctl_destroy_trace(trace, pid), "ustctl_destroy_trace - without ever starting");
>>>
>>> +	tap_ok(ustctl_set_marker_state(trace, "ustl", "blar", 1, pid) == 0,
>>> +	       "Enable non-existent marker ustl blar");
>>>
>>> 	printf("##### Tests that definetly should work are completed #####\n");
>>> 	printf("############## Start expected failure cases ##############\n");
>>>
>>> 	tap_ok(ustctl_set_marker_state(trace, "ust","bar", 1, pid),
>>> 	       "Enable already enabled marker ust/bar");
>>> -
>>> -	tap_ok(ustctl_set_marker_state(trace, "ustl", "blar", 1, pid),
>>> -	       "Enable non-existent marker ustl blar");
>>> +	tap_ok(EEXIST == errno,
>>> +	       "Right error code for enabling an already enabled marker");
>>>
>>> 	tap_ok(ustctl_start_trace(trace, pid),
>>> 	       "Start a non-existent trace");
>>> @@ -161,7 +163,7 @@ int main(int argc, char **argv)
>>> 	int i, status;
>>> 	pid_t parent_pid, child_pid;
>>>
>>> -	tap_plan(27);
>>> +	tap_plan(28);
>>>
>>> 	printf("Function tests for ustctl\n");
>>>
>>> --
>>> 1.7.2.3
>>>
>>>
>>> _______________________________________________
>>> ltt-dev mailing list
>>> ltt-dev at lists.casi.polymtl.ca
>>> http://lists.casi.polymtl.ca/cgi-bin/mailman/listinfo/ltt-dev
>>>
>>
>> _______________________________________________
>> ltt-dev mailing list
>> ltt-dev at lists.casi.polymtl.ca
>> http://lists.casi.polymtl.ca/cgi-bin/mailman/listinfo/ltt-dev
>>
>
> -- 
> Mathieu Desnoyers
> Operating System Efficiency R&D Consultant
> EfficiOS Inc.
> http://www.efficios.com
>