[PATCH v6 3/3] Linux: Only generate 64 bit timestamps for 64 bit time_t recvmsg/recvmmsg

[Florian Weimer]

* Adhemerval Zanella:

> The timestamps created by __convert_scm_timestamps only make sense for
> 64 bit time_t programs, 32 bit time_t programs will ignore 64 bit time_t
> timestamps since SO_TIMESTAMP will be defined to old values (either by
> glibc or kernel headers).
>
> Worse, if the buffer is not suffice MSG_CTRUNC is set to indicate it
> (which breaks some programs [1]).
>
> This patch makes only 64 bit time_t recvmsg and recvmmsg to call
> __convert_scm_timestamps.  Also, the assumption to called it is changed
> from __ASSUME_TIME64_SYSCALLS to __TIMESIZE != 64 since the setsockopt
> might be called by libraries built without __TIME_BITS=64.  The
> MSG_CTRUNC is only set for the 64 bit symbols, it should happen only
> if 64 bit time_t programs run older kernels.
>
> Checked on x86_64-linux-gnu and i686-linux-gnu.
>
> [1] https://github.com/systemd/systemd/pull/20567
> ---
>  include/sys/socket.h                          |  10 +-
>  sysdeps/unix/sysv/linux/Makefile              |  10 +-
>  sysdeps/unix/sysv/linux/recvmmsg.c            |  45 ++-
>  sysdeps/unix/sysv/linux/recvmsg.c             |  34 ++-
>  .../tst-socket-timestamp-compat-time64.c      |   1 +
>  .../sysv/linux/tst-socket-timestamp-compat.c  | 265 ++++++++++++++++++
>  6 files changed, 336 insertions(+), 29 deletions(-)
>  create mode 100644 sysdeps/unix/sysv/linux/tst-socket-timestamp-compat-time64.c
>  create mode 100644 sysdeps/unix/sysv/linux/tst-socket-timestamp-compat.c

Looks okay.

Reviewed-by: Florian Weimer <fweimer@redhat.com>

Thanks,
Florian