[LTP] Do we have some simple way to get the current cgroup.procs path?

[xuyang2018.jy@fujitsu.com]

Hi Li
> Hi Xu,
> 
> On Thu, Jul 14, 2022 at 2:02 PM xuyang2018.jy@fujitsu.com 
> <mailto:xuyang2018.jy@fujitsu.com> <xuyang2018.jy@fujitsu.com 
> <mailto:xuyang2018.jy@fujitsu.com>> wrote:
> 
>     Hi Richard, LI
> 
>     I am writting a simple regression test[1]that refer to kernel
>     selftest cgroup test_core[2]. I may name it as memcontrol05.c.
> 
>     It tests cgroup migration permission check should be performed based
>     on the credentials at the time of open instead of write.
> 
>     I have used ltp cgroup framework, but ltp cgroup only use
>     SAFE_CGROUP_PRINTF to write value.
> 
>     How can get the cgroup root_dir ltp_dir path? So I can open this fd
>     and change/save effective uid between open and write?
> 
> Not sure if I fully understand your requirements.
> Can we achieve this test by creating a two-layer subdirectory?

I think yes.

> 
> Does only the root/ltp_dir mandatory for completing your test?

It also need gettid subdirectory and cgroup name.
> If yes, I think tst_cg_print_config() maybe fits your purpose,
> but that would need additional function help extracting that.
> 
> Take a reference to see how Luke gets the root path (in shell):
> https://lists.linux.it/pipermail/ltp/2022-April/028772.html
> <https://lists.linux.it/pipermail/ltp/2022-April/028772.html>

Thanks, I prefer to use c api and will think about it continuely.

Best Regards
Yang Xu
> 
> 
> -- 
> Regards,
> Li Wang