As per Austin Group interpretation, "the object" wrt a
dangling symlink is the symlink itself, despite FTW_PHYS.

Reviewed-by: Tulio Magno Quites Machado Filho <tuliom@linux.ibm.com>

The kernel is evolving this interface (e.g., removal of the
restriction on cross-device copies), and keeping up with that
is difficult.  Applications which need the function should
run kernels which support the system call instead of relying on
the imperfect glibc emulation.

Reviewed-by: Adhemerval Zanella <adhemerval.zanella@linaro.org>

This will automatically import new STATX_* constants.  It also avoids
a conflict between <sys/stat.h> and <linux/stat.h>.

With internal fcntl64 internal (commit 06ab719d), it is possible to
consolidate lockf implementation by using the LFS fcntl interface
instead of using arch and system-specific implementations.

For Linux, the i386 implementation is used as generic implementation
by replacing the direct syscall with fcntl64 call.  The LFS symbol
alias for default LFS ABI (__OFF_T_MATCHES_OFF64_T) is used to avoid
the duplicate symbol (instead of overriding the implementation with an
empty file).

For Hurd lockf64 semantic is changed: previous generic lockf64
implementation returned EOVERFLOW if LEN input is larger than 32-bit
off_t.  However, Hurd fcntl64 implementation for F_GETLK64, F_SETLK64,
and F_SETLKW64 do accept off64_t inputs (__f_setlk accepts only off64_t
inputs).

Checked on i686-linux-gnu and x86_64-linux-gnu along with a i686-gnu
build.

	* io/Makefile (tests): Add tst-lockf.
	* io/lockf.c (lockf): Use __fcntl and only define for
	!__OFF_T_MATCHES_OFF64_T.
	* io/lockf64.c (__lockf64): Call __fcntl64 and alias to lockf for
	__OFF_T_MATCHES_OFF64_T case.
	* io/tst-lockf.c: New file.
	* sysdeps/unix/sysv/linux/i386/lockf64.c: Remove file.
	* sysdeps/unix/sysv/linux/arm/lockf64.c: Likewise.
	* sysdeps/unix/sysv/linux/m68k/lockf64.c: Likewise.
	* sysdeps/unix/sysv/linux/mips/mips32/lockf64.c: Likewise.
	* sysdeps/unix/sysv/linux/mips/mips64/n32/lockf64.c: Likewise.
	* sysdeps/unix/sysv/linux/powerpc/powerpc32/lockf64.c: Likewise.
	* sysdeps/unix/sysv/linux/s390/s390-32/lockf64.c: Likewise.
	* sysdeps/unix/sysv/linux/sh/lockf64.c: Likewise.
	* sysdeps/unix/sysv/linux/sparc/sparc32/lockf64.c: Likewise.

	* All files with FSF copyright notices: Update copyright dates
	using scripts/update-copyrights.
	* locale/programs/charmap-kw.h: Regenerated.
	* locale/programs/locfile-kw.h: Likewise.

This patch fixes the OFD ("file private") locks for architectures that
support non-LFS flock definition (__USE_FILE_OFFSET64 not defined). The
issue in this case is both F_OFD_{GETLK,SETLK,SETLKW} and
F_{SET,GET}L{W}K64 expects a flock64 argument and when using old
F_OFD_* flags with a non LFS flock argument the kernel might interpret
the underlying data wrongly.  Kernel idea originally was to avoid using
such flags in non-LFS syscall, but since GLIBC uses fcntl with LFS
semantic as default it is possible to provide the functionality and
avoid the bogus struct kernel passing by adjusting the struct manually
for the required flags.

The idea follows other LFS interfaces that provide two symbols:

  1. A new LFS fcntl64 is added on default ABI with the usual macros to
     select it for FILE_OFFSET_BITS=64.

  2. The Linux non-LFS fcntl use a stack allocated struct flock64 for
     F_OFD_{GETLK,SETLK,SETLKW} copy the results on the user provided
     struct.

  3. Keep a compat symbol with old broken semantic for architectures
     that do not define __OFF_T_MATCHES_OFF64_T.

So for architectures which defines __USE_FILE_OFFSET64, fcntl64 will
aliased to fcntl and no adjustment would be required.  So to actually
use F_OFD_* with LFS support the source must be built with LFS support
(_FILE_OFFSET_BITS=64).

Also F_OFD_SETLKW command is handled a cancellation point, as for
F_SETLKW{64}.

Checked on x86_64-linux-gnu and i686-linux-gnu.

	[BZ #20251]
	* NEWS: Mention fcntl64 addition.
	* csu/check_fds.c: Replace __fcntl_nocancel by __fcntl64_nocancel.
	* login/utmp_file.c: Likewise.
	* sysdeps/posix/fdopendir.c: Likewise.
	* sysdeps/posix/opendir.c: Likewise.
	* sysdeps/unix/pt-fcntl.c: Likewise.
	* include/fcntl.h (__libc_fcntl64, __fcntl64,
	__fcntl64_nocancel_adjusted): New prototype.
	(__fcntl_nocancel_adjusted): Remove prototype.
	* io/Makefile (routines): Add fcntl64.
	(CFLAGS-fcntl64.c): New rule.
	* io/Versions [GLIBC_2.28] (fcntl64): New symbol.
	[GLIBC_PRIVATE] (__libc_fcntl): Rename to __libc_fcntl64.
	* io/fcntl.h (fcntl64): Add prototype and redirect if
	__USE_FILE_OFFSET64 is defined.
	* io/fcntl64.c: New file.
	* manual/llio.text: Add a note for which commands fcntl acts a
	cancellation point.
	* nptl/Makefile (CFLAGS-fcntl64.c): New rule.
	* sysdeps/mach/hurd/fcntl.c: Alias fcntl to fcntl64 symbols.
	* sysdeps/mach/hurd/i386/libc.abilist [GLIBC_2.28] (fcntl, fcntl64):
	New symbols.
	* sysdeps/unix/sysv/linux/fcntl.c (__libc_fcntl): Fix F_GETLK64,
	F_OFD_GETLK, F_SETLK64, F_SETLKW64, F_OFD_SETLK, and F_OFD_SETLKW for
	non-LFS case.
	* sysdeps/unix/sysv/linux/fcntl64.c: New file.
	* sysdeps/unix/sysv/linux/fcntl_nocancel.c (__fcntl_nocancel): Rename
	to __fcntl64_nocancel.
	(__fcntl_nocancel_adjusted): Rename to __fcntl64_nocancel_adjusted.
	* sysdeps/unix/sysv/linux/not-cancel.h (__fcntl_nocancel): Rename
	to __fcntl64_nocancel.
	* sysdeps/unix/sysv/linux/tst-ofdlocks.c: New file.
	* sysdeps/unix/sysv/linux/tst-ofdlocks-compat.c: Likewise.
	* sysdeps/unix/sysv/linux/Makefile (tests): Add tst-ofdlocks.
	(tests-internal): Add tst-ofdlocks-compat.
	* sysdeps/unix/sysv/linux/aarch64/libc.abilist [GLIBC_2.28]
	(fcntl64): New symbol.
	* sysdeps/unix/sysv/linux/alpha/libc.abilist: Likewise.
	* sysdeps/unix/sysv/linux/ia64/libc.abilist: Likewise.
	* sysdeps/unix/sysv/linux/mips/mips64/n64/libc.abilist: Likewise.
	* sysdeps/unix/sysv/linux/powerpc/powerpc64/libc.abilist: Likewise.
	* sysdeps/unix/sysv/linux/powerpc/powerpc64/libc-le.abilist: Likewise.
	* sysdeps/unix/sysv/linux/riscv/rv64/libc.abilist: Likewise.
	* sysdeps/unix/sysv/linux/s390/s390-64/libc.abilist: Likewise.
	* sysdeps/unix/sysv/linux/sparc/sparc64/libc.abilist: Likewise.
	* sysdeps/unix/sysv/linux/x86_64/64/libc.abilist: Likewise.
	* sysdeps/unix/sysv/linux/x86_64/x32/libc.abilist: Likewise.
	* sysdeps/unix/sysv/linux/arm/libc.abilist [GLIBC_2.28] (fcntl,
	fcntl64): Likewise.
	* sysdeps/unix/sysv/linux/hppa/libc.abilist: Likewise.
	* sysdeps/unix/sysv/linux/i386/libc.abilis: Likewise.
	* sysdeps/unix/sysv/linux/m68k/coldfire/libc.abilist: Likewise.
	* sysdeps/unix/sysv/linux/m68k/m680x0/libc.abilist: Likewise.
	* sysdeps/unix/sysv/linux/microblaze/libc.abilist: Likewise.
	* sysdeps/unix/sysv/linux/mips/mips32/fpu/libc.abilist: Likewise.
	* sysdeps/unix/sysv/linux/mips/mips32/nofpu/libc.abilist: Likewise.
	* sysdeps/unix/sysv/linux/mips/mips64/n32/libc.abilist: Likewise.
	* sysdeps/unix/sysv/linux/nios2/libc.abilist: Likewise.
	* sysdeps/unix/sysv/linux/powerpc/powerpc32/fpu/libc.abilist:
	Likewise.
	* sysdeps/unix/sysv/linux/powerpc/powerpc32/nofpu/libc.abilist:
	Likewise.
	* sysdeps/unix/sysv/linux/s390/s390-32/libc.abilist: Likewise.
	* sysdeps/unix/sysv/linux/sh/libc.abilist: Likewise.
	* sysdeps/unix/sysv/linux/sparc/sparc32/libc.abilist: Likewise.

Currently getcwd(3) can succeed without returning an absolute path
because the underlying getcwd syscall, starting with linux commit
v2.6.36-rc1~96^2~2, may succeed without returning an absolute path.

This is a conformance issue because "The getcwd() function shall
place an absolute pathname of the current working directory
in the array pointed to by buf, and return buf".

This is also a security issue because a non-absolute path returned
by getcwd(3) causes a buffer underflow in realpath(3).

Fix this by checking the path returned by getcwd syscall and falling
back to generic_getcwd if the path is not absolute, effectively making
getcwd(3) fail with ENOENT.  The error code is chosen for consistency
with the case when the current directory is unlinked.

[BZ #22679]
CVE-2018-1000001
* sysdeps/unix/sysv/linux/getcwd.c (__getcwd): Fall back to
generic_getcwd if the path returned by getcwd syscall is not absolute.
* io/tst-getcwd-abspath.c: New test.
* io/Makefile (tests): Add tst-getcwd-abspath.

	* All files with FSF copyright notices: Update copyright dates
	using scripts/update-copyrights.
	* locale/programs/charmap-kw.h: Regenerated.
	* locale/programs/locfile-kw.h: Likewise.