The computation was correct on Linux only by luck because the cmsghdr size
is already aligned there.

Rename the identifier sz to __sz everywhere.

Fixes: a643f60c53 ("Make sure that the fortified function conditionals are constant")

This commit adds shutdown test with SHUT_RD, SHUT_WR, SHUT_RDWR for an
UNIX socket connection.

Reviewed-by: DJ Delorie <dj@redhat.com>

This supports common coding patterns.  The GCC C front end before
version 7 rejects the may_alias attribute on a struct definition
if it was not present in a previous forward declaration, so this
attribute can only be conditionally applied.

This implements the spirit of the change in Austin Group issue 1641.

Suggested-by: Marek Polacek <polacek@redhat.com>
Suggested-by: Jakub Jelinek <jakub@redhat.com>
Reviewed-by: Sam James <sam@gentoo.org>
Reviewed-by: Carlos O'Donell <carlos@redhat.com>

This commit adds a simple bind/accept/connect test for an IPv4 TCP
connection to a local process via the loopback interface.

Reviewed-by: Arjun Shankar <arjun@redhat.com>

It was raised on libc-help [1] that some Linux kernel interfaces expect
the libc to define __USE_TIME_BITS64 to indicate the time_t size for the
kABI.  Different than defined by the initial y2038 design document [2],
the __USE_TIME_BITS64 is only defined for ABIs that support more than
one time_t size (by defining the _TIME_BITS for each module).

The 64 bit time_t redirects are now enabled using a different internal
define (__USE_TIME64_REDIRECTS). There is no expected change in semantic
or code generation.

Checked on x86_64-linux-gnu, i686-linux-gnu, aarch64-linux-gnu, and
arm-linux-gnueabi

[1] https://sourceware.org/pipermail/libc-help/2024-January/006557.html
[2] https://sourceware.org/glibc/wiki/Y2038ProofnessDesign

Reviewed-by: DJ Delorie <dj@redhat.com>

It improve fortify checks recv, recvfrom, poll, and ppoll.  The compile
and runtime hecks have similar coverage as with GCC.

Checked on aarch64, armhf, x86_64, and i686.
Reviewed-by: Carlos O'Donell <carlos@redhat.com>
Tested-by: Carlos O'Donell <carlos@redhat.com>

Since the _FORTIFY_SOURCE feature uses some routines of Glibc, they need to
be excluded from the fortification.

On top of that:
 - some tests explicitly verify that some level of fortification works
   appropriately, we therefore shouldn't modify the level set for them.
 - some objects need to be build with optimization disabled, which
   prevents _FORTIFY_SOURCE to be used for them.

Assembler files that implement architecture specific versions of the
fortified routines were not excluded from _FORTIFY_SOURCE as there is no
C header included that would impact their behavior.

Reviewed-by: Siddhesh Poyarekar <siddhesh@sourceware.org>