[LTP] [PATCH 1/2] syscalls/pidfd_open01.c: Add check for close-on-exec flag

[Xiao Yang]

On 5/5/20 11:28 AM, Viresh Kumar wrote:
> On 04-05-20, 19:31, Xiao Yang wrote:
>> On 5/4/20 1:09 PM, Viresh Kumar wrote:
>>> On 30-04-20, 16:57, Xiao Yang wrote:
>>>> pidfd_open(2) will set close-on-exec flag on the file descriptor as it
>>>> manpage states, so check close-on-exec flag by fcntl(2).
>>>>
>>>> Also avoid compiler warning by replacing (long) TST_RET with (int) pidfd:
>>>> ------------------------------------------------------
>>>> In file included from pidfd_open01.c:9:
>>>> pidfd_open01.c: In function ‘run’:
>>>> ../../../../include/tst_test.h:76:41: warning: format ‘%i’ expects argument of type ‘int’, but argument 5 has type ‘long int’ [-Wformat=]
>>>>      76 |   tst_brk_(__FILE__, __LINE__, (ttype), (arg_fmt), ##__VA_ARGS__);\
>>>>         |                                         ^~~~~~~~~
>>>> ../../../../include/tst_safe_macros.h:224:5: note: in expansion of macro ‘tst_brk’
>>>>     224 |     tst_brk(TBROK | TERRNO,                          \
>>>>         |     ^~~~~~~
>>>> pidfd_open01.c:20:9: note: in expansion of macro ‘SAFE_FCNTL’
>>>>      20 |  flag = SAFE_FCNTL(TST_RET, F_GETFD);
>>> This log isn't useful as the warning started coming after your change
>>> only and not before.
>> Hi Viresh,
>>
>> Thanks for your review.
>>
>> Right，just add a hint why I use pidfd instead so I want to keep it.
>>
>> Of course，I will mention that my change introduces the compiler warning in
>> v2 patch.
> Even that isn't required really. You can add a variable if you like.

Hi Viresh,

Thanks a lot for your review.

I prefer to keep it :-).

>
>>>> ------------------------------------------------------
>>>>
>>>> Signed-off-by: Xiao Yang <yangx.jy@cn.fujitsu.com>
>>>> ---
>>>>    .../kernel/syscalls/pidfd_open/pidfd_open01.c  | 18 ++++++++++++++----
>>>>    1 file changed, 14 insertions(+), 4 deletions(-)
>>>>
>>>> diff --git a/testcases/kernel/syscalls/pidfd_open/pidfd_open01.c b/testcases/kernel/syscalls/pidfd_open/pidfd_open01.c
>>>> index 93bb86687..293e93b63 100644
>>>> --- a/testcases/kernel/syscalls/pidfd_open/pidfd_open01.c
>>>> +++ b/testcases/kernel/syscalls/pidfd_open/pidfd_open01.c
>>>> @@ -6,17 +6,27 @@
>>>>     * Basic pidfd_open() test, fetches the PID of the current process and tries to
>>>>     * get its file descriptor.
>>>>     */
>>>> +
>>>> +#include <sys/types.h>
>>>> +#include <unistd.h>
>>>> +#include <fcntl.h>
>>>>    #include "tst_test.h"
>>>>    #include "lapi/pidfd_open.h"
>>>>    static void run(void)
>>>>    {
>>>> -	TEST(pidfd_open(getpid(), 0));
>>>> +	int pidfd = 0, flag = 0;
>>> None of these need to be initialized.
>> Initialization or not initialization are both fine for me.
>>
>> Do you have any strong reason to drop Initialization?
> Initializations are only required if there is a chance of the variable
> getting used without being initialized, which isn't the case here.
> Whatever value you set to these variables, they will get overwritten
> anyway.

Right, they will get overwritten anyway.

As my previous reply said, either of them is OK for me so I can drop 
initializations as you suggested.

>
>>>> +
>>>> +	pidfd = pidfd_open(getpid(), 0);
>>>> +	if (pidfd == -1)
>>>> +		tst_brk(TFAIL | TERRNO, "pidfd_open(getpid(), 0) failed");
>>> This could have been written as:
>>>           TEST(pidfd = pidfd_open(getpid(), 0));
>> Why do you want to keep TEST()? I don't think it is necessary:
>>
>> 1) pidfd and TERRNO are enough to check return value and errno.
>>
>> 2) It is OK for testcase to not use TEST().
> As far as I have understood, that is the preferred way of doing it
> from LTP maintainers.
>
> Over that it was already there, why remove it now ? Just fix the
> problems you are trying to fix and that should be good.

Hi Cyril,

TEST() seems surplus after my change so I want to remove it directly.

I wonder if it is necessary to keep TEST()?

Thanks,

Xiao Yang

>