[LTP] [PATCH] shmget02: fix EPERM test when RLIMIT_MEMLOCK is large enough

[xuyang2018.jy@fujitsu.com <xuyang2018.jy@fujitsu.com>]

Hi!
Pushed with moving this into setup, thanks.

Best Regards
Yang Xu
> Hi Thadeu
>> shmget(..., SHM_HUGETLB) will not fail with EPERM if there is enough
>> space
>> for RLIMIT_MEMLOCK. If the limit is 0, it will fail with EPERM as
>> expected
>> when a not enough privileged user calls it.
>>
>> Set RLIMIT_MEMLOCK to 0 for all calls, as this is the only one which will
>> fail because of that limit, unless we are talking about very old kernels
>> (before 2.6.9).
>>
>> Fixes: 4dc493b44a85 ("syscalls/shmget*: Convert into new api")
>> Signed-off-by: Thadeu Lima de Souza Cascardo<cascardo@canonical.com>
> Thanks for the fix!
> Reviewed-by: Yang Xu <xuyang2018.jy@fujitsu.com>
>
> just a small nit: Since a child process created via fork(2) inherits its
> parent's resource limits. I prefer to move it to setup function, so we
> don't need to set it in each sub case.
>
> Best Regards
> Yang Xu
>> ---
>> testcases/kernel/syscalls/ipc/shmget/shmget02.c | 2 ++
>> 1 file changed, 2 insertions(+)
>>
>> diff --git a/testcases/kernel/syscalls/ipc/shmget/shmget02.c
>> b/testcases/kernel/syscalls/ipc/shmget/shmget02.c
>> index 6be8d8157999..8857207cfd3d 100644
>> --- a/testcases/kernel/syscalls/ipc/shmget/shmget02.c
>> +++ b/testcases/kernel/syscalls/ipc/shmget/shmget02.c
>> @@ -64,6 +64,7 @@ static void do_test(unsigned int n)
>> {
>> struct tcase *tc =&tcases[n];
>> pid_t pid;
>> + struct rlimit rl = { 0, 0 };
>>
>> if (tc->exp_user == 0&& tc->exp_group == 0) {
>> TST_EXP_FAIL2(shmget(*tc->shmkey, tc->size, tc->flags), tc->exp_err,
>> @@ -78,6 +79,7 @@ static void do_test(unsigned int n)
>> SAFE_SETGID(pw->pw_gid);
>> }
>> SAFE_SETUID(pw->pw_uid);
>> + SAFE_SETRLIMIT(RLIMIT_MEMLOCK,&rl);
>> TST_EXP_FAIL2(shmget(*tc->shmkey, tc->size, tc->flags), tc->exp_err,
>> "shmget(%i, %lu, %i)", *tc->shmkey, tc->size, tc->flags);
>> exit(0);