Re: [PATCH 29/51] tests/qtest: libqtest: Install signal handler via signal()

[Bin Meng]

On Wed, Aug 31, 2022 at 10:16 PM Marc-André Lureau
<marcandre.lureau@gmail.com> wrote:
>
> Hi
>
> On Wed, Aug 24, 2022 at 2:47 PM Bin Meng <bmeng.cn@gmail.com> wrote:
>>
>> From: Bin Meng <bin.meng@windriver.com>
>>
>> At present the codes uses sigaction() to install signal handler with
>> a flag SA_RESETHAND. Such usage can be covered by the signal() API
>> that is a simplified interface to the general sigaction() facility.
>>
>> Update to use signal() to install the signal handler, as it is
>> avaiable on Windows which we are going to support.
>>
>> Signed-off-by: Bin Meng <bin.meng@windriver.com>
>> ---
>>
>>  tests/qtest/libqtest.c | 14 +++-----------
>>  1 file changed, 3 insertions(+), 11 deletions(-)
>>
>> diff --git a/tests/qtest/libqtest.c b/tests/qtest/libqtest.c
>> index 1b24a4f1f7..70d7578740 100644
>> --- a/tests/qtest/libqtest.c
>> +++ b/tests/qtest/libqtest.c
>> @@ -68,7 +68,7 @@ struct QTestState
>>  QTestState *global_qtest;
>>
>>  static GHookList abrt_hooks;
>> -static struct sigaction sigact_old;
>> +static sighandler_t sighandler_old;
>>
>>  static int qtest_query_target_endianness(QTestState *s);
>>
>> @@ -181,20 +181,12 @@ static void sigabrt_handler(int signo)
>>
>>  static void setup_sigabrt_handler(void)
>>  {
>> -    struct sigaction sigact;
>> -
>> -    /* Catch SIGABRT to clean up on g_assert() failure */
>> -    sigact = (struct sigaction){
>> -        .sa_handler = sigabrt_handler,
>> -        .sa_flags = SA_RESETHAND,
>> -    };
>> -    sigemptyset(&sigact.sa_mask);
>> -    sigaction(SIGABRT, &sigact, &sigact_old);
>> +    sighandler_old = signal(SIGABRT, sigabrt_handler);
>>  }
>>
>>  static void cleanup_sigabrt_handler(void)
>>  {
>> -    sigaction(SIGABRT, &sigact_old, NULL);
>> +    signal(SIGABRT, sighandler_old);
>>  }
>>
>>  static bool hook_list_is_empty(GHookList *hook_list)
>> --
>
>
>
> We should keep the sigaction() version for !WIN32, it has notoriously less 
> issues, more modern etc. signal() only on win32.
>
> Although in this particular usage, I don't think that makes much difference...


Yes, as I mentioned in the commit message, the codes uses sigaction()
to install signal handler with a flag SA_RESETHAND, and such can be
replaced by the signal() API.

It is still a supported API in POSIX so we should be safe to use it to
simplify the code paths. Unless you are strongly against this?

Regards,
Bin