Since Linux 6.11 the kernel allows path to be NULL if flags &
AT_EMPTY_PATH.  Let's allow users to take the advantage if they don't
care running on old kernels.

Signed-off-by: Miao Wang <shankerwangmiao@gmail.com>
Signed-off-by: Xi Ruoyao <xry111@xry111.site>
Reviewed-by: Florian Weimer <fweimer@redhat.com>

This matches kernel behavior.  With this change, it is possible
to use utimensat as a replacement for the futimens interface,
similar to what glibc does internally.

Reviewed-by: Paul Eggert <eggert@cs.ucla.edu>

When building with e.g. -std=c99 and _ATFILE_SOURCE, stat.h was missing
including bits/types/struct_timespec.h to get the struct timespec
declaration for utimensat.

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>

This fixes a typo.
Reviewed-by: Adhemerval Zanella  <adhemerval.zanella@linaro.org>

I used these shell commands:

../glibc/scripts/update-copyrights $PWD/../gnulib/build-aux/update-copyright
(cd ../glibc && git commit -am"[this commit message]")

and then ignored the output, which consisted lines saying "FOO: warning:
copyright statement not found" for each of 7061 files FOO.

I then removed trailing white space from math/tgmath.h,
support/tst-support-open-dev-null-range.c, and
sysdeps/x86_64/multiarch/strlen-vec.S, to work around the following
obscure pre-commit check failure diagnostics from Savannah.  I don't
know why I run into these diagnostics whereas others evidently do not.

remote: *** 912-#endif
remote: *** 913:
remote: *** 914-
remote: *** error: lines with trailing whitespace found
...
remote: *** error: sysdeps/unix/sysv/linux/statx_cp.c: trailing lines

A new build flag, _TIME_BITS, enables the usage of the newer 64-bit
time symbols for legacy ABI (where 32-bit time_t is default).  The 64
bit time support is only enabled if LFS (_FILE_OFFSET_BITS=64) is
also used.

Different than LFS support, the y2038 symbols are added only for the
required ABIs (armhf, csky, hppa, i386, m68k, microblaze, mips32,
mips64-n32, nios2, powerpc32, sparc32, s390-32, and sh).  The ABIs with
64-bit time support are unchanged, both for symbol and types
redirection.

On Linux the full 64-bit time support requires a minimum of kernel
version v5.1.  Otherwise, the 32-bit fallbacks are used and might
results in error with overflow return code (EOVERFLOW).

The i686-gnu does not yet support 64-bit time.

This patch exports following rediretions to support 64-bit time:

  * libc:
    adjtime
    adjtimex
    clock_adjtime
    clock_getres
    clock_gettime
    clock_nanosleep
    clock_settime
    cnd_timedwait
    ctime
    ctime_r
    difftime
    fstat
    fstatat
    futimens
    futimes
    futimesat
    getitimer
    getrusage
    gettimeofday
    gmtime
    gmtime_r
    localtime
    localtime_r
    lstat_time
    lutimes
    mktime
    msgctl
    mtx_timedlock
    nanosleep
    nanosleep
    ntp_gettime
    ntp_gettimex
    ppoll
    pselec
    pselect
    pthread_clockjoin_np
    pthread_cond_clockwait
    pthread_cond_timedwait
    pthread_mutex_clocklock
    pthread_mutex_timedlock
    pthread_rwlock_clockrdlock
    pthread_rwlock_clockwrlock
    pthread_rwlock_timedrdlock
    pthread_rwlock_timedwrlock
    pthread_timedjoin_np
    recvmmsg
    sched_rr_get_interval
    select
    sem_clockwait
    semctl
    semtimedop
    sem_timedwait
    setitimer
    settimeofday
    shmctl
    sigtimedwait
    stat
    thrd_sleep
    time
    timegm
    timerfd_gettime
    timerfd_settime
    timespec_get
    utime
    utimensat
    utimes
    utimes
    wait3
    wait4

  * librt:
    aio_suspend
    mq_timedreceive
    mq_timedsend
    timer_gettime
    timer_settime

  * libanl:
    gai_suspend

Reviewed-by: Lukasz Majewski <lukma@denx.de>
Reviewed-by: Carlos O'Donell <carlos@redhat.com>
Tested-by: Carlos O'Donell <carlos@redhat.com>