Re: [PATCH v5 3/3] Linux: Only generate 64 bit timestamps for 64 bit time_t recvmsg/recvmmsg

[Adhemerval Zanella <adhemerval.zanella@linaro.org>]

On 28/01/2022 11:02, Florian Weimer wrote:
> * Adhemerval Zanella:
> 
>> diff --git a/sysdeps/unix/sysv/linux/tst-socket-timestamp-compat.c b/sysdeps/unix/sysv/linux/tst-socket-timestamp-compat.c
> 
>> +/* Check if recvmsg create the additional 64 bit timestamp if only 32 bit
>> +   is enabled for 64 bit recvmsg symbol.  */
>> +static void
>> +do_test_large_buffer (bool mc)
>> +{
>> +  struct mmsghdr mmhdr = { 0 };
>> +  /* It should be large enought for either timeval/timespec and the
>> +     64 time type as well.  */
>> +  char msgbuf[512];
> 
> I think this needs a union with struct cmsgbuf to ensure alignment.
> Alternatively, use malloc.

Yeah, it does require to setup the alignment. I will change to use an union.

> 
> 
>> +static void
>> +do_test_small_buffer (bool mc)
>> +{
>> +  struct mmsghdr mmhdr = { 0 };
>> +
>> +  /* Enable 32 bit timeval precision and check if no 64 bit timeval stamp
>> +     is created.  */
>> +  {
>> +    char msgbuf[CMSG_SPACE (sizeof (struct timeval))];
> 
> Likewise.
> 
> Rest looks okay.  The kernel does not pass on whether a time32 or time64
> system call was used, so implementing time32 recvmsg with recvmsg_time64
> is fine in that regard.
> 
> Thanks,
> Florian
>