Commit Graph

40963 Commits

Author SHA1 Message Date
H.J. Lu
46c9997413 x86: Define MINIMUM_X86_ISA_LEVEL in config.h [BZ #31676]
Define MINIMUM_X86_ISA_LEVEL at configure time to avoid

/usr/bin/ld: …/build/elf/librtld.os: in function `init_cpu_features':
…/git/elf/../sysdeps/x86/cpu-features.c:1202: undefined reference to `_dl_runtime_resolve_fxsave'
/usr/bin/ld: …/build/elf/librtld.os: relocation R_X86_64_PC32 against undefined hidden symbol `_dl_runtime_resolve_fxsave' can not be used when making a shared object
/usr/bin/ld: final link failed: bad value
collect2: error: ld returned 1 exit status

when glibc is built with -march=x86-64-v3 and configured with
--with-rtld-early-cflags=-march=x86-64, which is used to allow ld.so to
print an error message on unsupported CPUs:

Fatal glibc error: CPU does not support x86-64-v3

This fixes BZ #31676.
Reviewed-by: Sunil K Pandey <skpgkp2@gmail.com>
2024-04-24 04:50:56 -07:00
caiyinyu
095067efdf LoongArch: Add glibc.cpu.hwcap support.
The current IFUNC selection is always using the most recent
features which are available via AT_HWCAP.  But in
some scenarios it is useful to adjust this selection.

The environment variable:

GLIBC_TUNABLES=glibc.cpu.hwcaps=-xxx,yyy,zzz,....

can be used to enable HWCAP feature yyy, disable HWCAP feature xxx,
where the feature name is case-sensitive and has to match the ones
used in sysdeps/loongarch/cpu-tunables.c.

Signed-off-by: caiyinyu <caiyinyu@loongson.cn>
2024-04-24 18:22:38 +08:00
Florian Weimer
f4724843ad nptl: Fix tst-cancel30 on kernels without ppoll_time64 support
Fall back to ppoll if ppoll_time64 fails with ENOSYS.
Fixes commit 370da8a121 ("nptl: Fix
tst-cancel30 on sparc64").

Reviewed-by: Adhemerval Zanella <adhemerval.zanella@linaro.org>
2024-04-23 21:16:32 +02:00
Samuel Thibault
16c8dfba14 Revert "Allow glibc to be compiled without EXEC_PAGESIZE"
This reverts commit 49aa652db8.

This is still being discussed.
2024-04-22 23:00:18 +02:00
Carlos O'Donell
684fbab755 locale: Handle loading a missing locale twice (Bug 14247)
Delay setting file->decided until the data has been successfully loaded
by _nl_load_locale().  If the function fails to load the data then we
must return and error and leave decided untouched to allow the caller to
attempt to load the data again at a later time.  We should not set
decided to 1 early in the function since doing so may prevent attempting
to load it again. We want to try loading it again because that allows an
open to fail and set errno correctly.

On the other side of this problem is that if we are called again with
the same inputs we will fetch the cached version of the object and carry
out no open syscalls and that fails to set errno so we must set errno to
ENOENT in that case.  There is a second code path that has to be handled
where the name of the locale matches but the codeset doesn't match.

These changes ensure that errno is correctly set on failure in all the
return paths in _nl_find_locale().

Adds tst-locale-loadlocale to cover the bug.

No regressions on x86_64.

Co-authored-by: Jeff Law <law@redhat.com>
Reviewed-by: Adhemerval Zanella  <adhemerval.zanella@linaro.org>
2024-04-22 16:03:00 -04:00
Adhemerval Zanella
25b191f6d3 elf: Do not check for loader mmap on tst-decorate-maps (BZ 31553)
On some architectures and depending on the page size, the loader can
also allocate some memory during dependencies loading and it will be
marked as 'loader malloc'.  However, if the system page size is
large enough, the initial data page will be enough for all required
allocation and there will be no extra loader mmap.  To avoid false
negatives, the test does not check for such pages.

Checked on powerpc64le-linux-gnu with 64k pagesize.
Reviewed-by: Simon Chopin <simon.chopin@canonical.com>
2024-04-22 15:39:48 -03:00
Joseph Myers
f6d18bea38 Use --enable-obsolete in build-many-glibcs.py for nios2-linux-gnu
Until GCC removes Nios II support (at which point we should do so as
well), this is now needed for GCC 14 / mainline to build for
nios2-linux-gnu target.

Tested with build-many-glibcs.py (GCC mainline) for nios2-linux-gnu.
2024-04-19 17:03:56 +00:00
Florian Weimer
5361ad3910 login: Use unsigned 32-bit types for seconds-since-epoch
These fields store timestamps when the system was running.  No Linux
systems existed before 1970, so these values are unused.  Switching
to unsigned types allows continued use of the existing struct layouts
beyond the year 2038.

The intent is to give distributions more time to switch to improved
interfaces that also avoid locking/data corruption issues.

Reviewed-by: Adhemerval Zanella  <adhemerval.zanella@linaro.org>
2024-04-19 14:38:17 +02:00
Florian Weimer
9abdae94c7 login: structs utmp, utmpx, lastlog _TIME_BITS independence (bug 30701)
These structs describe file formats under /var/log, and should not
depend on the definition of _TIME_BITS.  This is achieved by
defining __WORDSIZE_TIME64_COMPAT32 to 1 on 32-bit ports that
support 32-bit time_t values (where __time_t is 32 bits).

Reviewed-by: Adhemerval Zanella  <adhemerval.zanella@linaro.org>
2024-04-19 14:38:17 +02:00
Florian Weimer
4d4da5aab9 login: Check default sizes of structs utmp, utmpx, lastlog
The default <utmp-size.h> is for ports with a 64-bit time_t.
Ports with a 32-bit time_t or with __WORDSIZE_TIME64_COMPAT32=1
need to override it.

Reviewed-by: Adhemerval Zanella  <adhemerval.zanella@linaro.org>
2024-04-19 14:38:17 +02:00
Wilco Dijkstra
0997c3d0c8 benchtests: Add random() benchmark
Add a simple benchmark to measure the overhead of internal libc locks in
the random() implementation on both single- and multi-threaded cases.
This relies on the implementation of random using internal locks to
access shared global data, and that the runtime uses multi-threaded
locking once a thread has been created (even after it finishes).

Reviewed-by: Adhemerval Zanella  <adhemerval.zanella@linaro.org>
2024-04-18 14:30:21 +01:00
Siddhesh Poyarekar
05c3495296 advisories: Add Reported-By
Add a new tag to give credit to vulnerability discoverers.

Signed-off-by: Siddhesh Poyarekar <siddhesh@sourceware.org>
2024-04-18 08:52:46 -04:00
Adhemerval Zanella
0e53e7cdf5 Fix 'Reported-By' to use Camel Case for commit 6a98f4640e 2024-04-17 14:27:42 -03:00
Adhemerval Zanella
6a98f4640e Document CVE-2024-2961
This commit adds "advisories" entries for the above three CVEs.
2024-04-17 14:24:26 -03:00
Charles Fol
f9dc609e06 iconv: ISO-2022-CN-EXT: fix out-of-bound writes when writing escape sequence (CVE-2024-2961)
ISO-2022-CN-EXT uses escape sequences to indicate character set changes
(as specified by RFC 1922).  While the SOdesignation has the expected
bounds checks, neither SS2designation nor SS3designation have its;
allowing a write overflow of 1, 2, or 3 bytes with fixed values:
'$+I', '$+J', '$+K', '$+L', '$+M', or '$*H'.

Checked on aarch64-linux-gnu.

Co-authored-by: Adhemerval Zanella  <adhemerval.zanella@linaro.org>
Reviewed-by: Carlos O'Donell <carlos@redhat.com>
Tested-by: Carlos O'Donell <carlos@redhat.com>
2024-04-17 09:21:40 -03:00
Joe Simmons-Talbott
59974938fe elf/rtld: Count skipped environment variables for enable_secure
When using the glibc.rtld.enable_secure tunable we need to keep track of
the count of environment variables we skip due to __libc_enable_secure
being set and adjust the auxv section of the stack.  This fixes an
assertion when running ld.so directly with glibc.rtld.enable_secure set.
Add a testcase that ensures the assert is not hit.

elf/rtld.c:1324   assert (auxv == sp + 1);

Reviewed-by: Adhemerval Zanella  <adhemerval.zanella@linaro.org>
2024-04-16 20:32:10 +00:00
Florian Weimer
14e56bd4ce powerpc: Fix ld.so address determination for PCREL mode (bug 31640)
This seems to have stopped working with some GCC 14 versions,
which clobber r2.  With other compilers, the kernel-provided
r2 value is still available at this point.

Reviewed-by: Peter Bergner <bergner@linux.ibm.com>
2024-04-14 08:24:51 +02:00
Florian Weimer
aea52e3d2b Revert "x86_64: Suppress false positive valgrind error"
This reverts commit a1735e0aa8.

The test failure is a real valgrind bug that needs to be fixed before
valgrind is usable with a glibc that has been built with
CC="gcc -march=x86-64-v3".  The proposed valgrind patch teaches
valgrind to replace ld.so strcmp with an unoptimized scalar
implementation, thus avoiding any AVX2-related problems.

Valgrind bug: <https://bugs.kde.org/show_bug.cgi?id=485487>

Reviewed-by: H.J. Lu <hjl.tools@gmail.com>
2024-04-13 17:42:13 +02:00
Adhemerval Zanella
cf11e74b0d wcsmbs: Ensure wcstr worst-case linear execution time (BZ 23865)
It uses the same two-way algorithm used on strstr, strcasestr, and
memmem.  Different than strstr, neither the "shift table" optimization
nor the self-adapting filtering check is used because it would result in
a too-large shift table (and it also simplifies the implementation bit).

Checked on x86_64-linux-gnu and aarch64-linux-gnu.
Reviewed-by: DJ Delorie <dj@redhat.com>
2024-04-11 14:21:32 -03:00
Adhemerval Zanella
4b717562c4 wcsmbs: Add test-wcsstr
Parametrize test-strstr.c so it can be used to check wcsstr.

Checked on x86_64-linux-gnu and aarch64-linux-gnu.

Reviewed-by: DJ Delorie <dj@redhat.com>
2024-04-11 14:21:32 -03:00
Adhemerval Zanella
686d542025 posix: Sync tempname with gnulib
The gnulib version contains an important change (9ce573cde), which
fixes some problems with multithreading, entropy loss, and ASLR leak
nfo.  It also fixes an issue where getrandom is not being used
on some new files generation (only for __GT_NOCREATE on first try).

The 044bf893ac removed __path_search, which is now moved to another
gnulib shared files (stdio-common/tmpdir.{c,h}).  Tthis patch
also fixes direxists to use __stat64_time64 instead of __xstat64,
and move the include of pathmax.h for !_LIBC (since it is not used
by glibc).  The license is also changed from GPL 3.0 to 2.1, with
permission from the authors (Bruno Haible and Paul Eggert).

The sync also removed the clock fallback, since clock_gettime
with CLOCK_REALTIME is expected to always succeed.

It syncs with gnulib commit 323834962817af7b115187e8c9a833437f8d20ec.

Checked on x86_64-linux-gnu.

Co-authored-by: Bruno Haible <bruno@clisp.org>
Co-authored-by: Paul Eggert <eggert@cs.ucla.edu>
Reviewed-by: Bruno Haible <bruno@clisp.org>
2024-04-10 14:53:39 -03:00
Sergey Kolosov
3a83f79024 socket: Add new test for connect
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>
2024-04-10 18:10:22 +02:00
Sergey Kolosov
6687a6e3f9 libsupport: Add xgetpeername
The patch adds redirections for getpeername.

Reviewed-by: Arjun Shankar <arjun@redhat.com>
2024-04-10 18:10:22 +02:00
H.J. Lu
42e48e720c nptl: Add tst-pthread-key1-static for BZ #21777
Add a static pthread static tests to verify that BZ #21777 is fixed.

Reviewed-by: Florian Weimer <fweimer@redhat.com>
2024-04-09 05:27:03 -07:00
Florian Weimer
ae7468a7b0 elf: Add ld.so test with non-existing program name
None of the existing tests seem to cover the case where
_dl_signal_error is called without an active error handler.
The new elf/tst-rtld-does-not-exist test triggers such a
_dl_signal_error call from _dl_map_object.

Reviewed-by: H.J. Lu <hjl.tools@gmail.com>
2024-04-08 19:19:09 +02:00
H.J. Lu
1cce91d8ae elf: Check objname before calling fatal_error
_dl_signal_error may be called with objname == NULL.  _dl_exception_create
checks objname == NULL.  But fatal_error doesn't.  Check objname before
calling fatal_error.  This fixes BZ #31596.
Reviewed-by: Sunil K Pandey <skpgkp2@gmail.com>
2024-04-08 09:41:02 -07:00
H.J. Lu
727aacfd66 Use crtbeginT.o and crtend.o for non-PIE static executables
When static PIE is enabled by default, we shouldn't use crtbeginS.o and
crtendS.o for non-PIE static executables.  Check $($(@F)-no-pie) to use
crtbeginT.o and crtend.o to create non-PIE static executables.
Reviewed-by: Sunil K Pandey <skpgkp2@gmail.com>
2024-04-08 09:25:36 -07:00
Florian Weimer
f8d8b1b1e6 aarch64: Enhanced CPU diagnostics for ld.so
This prints some information from struct cpu_features, and the midr_el1
and dczid_el0 system register contents on every CPU.

Reviewed-by: Szabolcs Nagy <szabolcs.nagy@arm.com>
2024-04-08 16:48:55 +02:00
Florian Weimer
7a430f40c4 x86: Add generic CPUID data dumper to ld.so --list-diagnostics
This is surprisingly difficult to implement if the goal is to produce
reasonably sized output.  With the current approaches to output
compression (suppressing zeros and repeated results between CPUs,
folding ranges of identical subleaves, dealing with the %ecx
reflection issue), the output is less than 600 KiB even for systems
with 256 logical CPUs.

Reviewed-by: H.J. Lu <hjl.tools@gmail.com>
2024-04-08 16:48:55 +02:00
Florian Weimer
5653ccd847 elf: Add CPU iteration support for future use in ld.so diagnostics
Reviewed-by: Szabolcs Nagy <szabolcs.nagy@arm.com>
2024-04-08 16:48:55 +02:00
Paul Eggert
1f94147a79 timezone: sync to TZDB 2024a
Sync tzselect, zdump, zic to TZDB 2024a.
This patch incorporates the following TZDB source code changes,
listed roughly in descending order of importance.

  zic now supports links to links, needed for future tzdata
  zic now defaults to '-b slim'
  zic now updates output files atomically
  zic has new options -R, -l -, -p -
  zic -r now uses -00 for unspecified timestamps
  zdump now uses [lo,hi) for both -c and -t
  Fix several integer overflow bugs
  zic now checks input bytes more carefully
  Simplify and fix new TZDIR setup
  Default time_t to 64 bits on glibc 2.34+ 32-bit
  zic now generates TZ strings that conform to POSIX when all-year DST
  zic -v now shows extreme-int tm_year transitions
  Fix zic bug in last time type of Asia/Gaza etc.
  Fix zic bug with Palestine after 2075
  Fix bug uncovered by recent change to Iran history
  Fix 'zic -b fat' bug with Port Moresby 32-bit data
  Fix zic bug with -r @X where X is deduced from TZ
  Fix bug with zic -r cutoff before 1st transition
  Fix leap second expiry and truncation
  Fix zic bug on Linux 2.6.16 and 2.6.17
  Fix bug with 'zic -d /a/b/c' if /a is unwriteable
  Don't mistruncate TZif files at leap seconds
  Fix zdump undefined behavior if !USE_LTZ
  zdump -v reports localtime+gmtime failures better
  Fix zdump diagnostic for missing timezone
  Don't assume nonempty argv
  Port better to C23
  Do not assume negative >> behavior
  I18nize zdump a bit better
  Port zdump to right_only installations
  New tzselect menu option 'now'
  tzselect can now use current time to help choose
  Improve tzselect behavior for Turkey etc.
  tzselect: do not create temporary files
  tzselect: work around mawk bug with {2,}
  tzselect: Port to POSIX awk, which prohibits -v newlines
  Do not use empty RE in tzselect
  Don't set TZ in tzselect
  Avoid sed, expr in tzselect
  tzselect: Fix problems with spaces in TZDIR
  Improve tzselect diagnostics
  Remove zic workaround for Qt bug 53071
  Remove zic support for "min" in Rule lines
  Remove zic support for zic -y, Rule TYPEs, pacificnew
  Remove tzselect workaround for Bash 1.14.7 bug

* SHARED-FILES: Update to match current sync.
* config.h.in (HAVE_STRERROR): Remove; no longer needed.
* timezone/Makefile ($(objpfx)zic.o): Depend on tzdir.h.
($(objpfx)tzdir.h): New rule to build a placeholder.
* timezone/private.h, timezone/tzfile.h, timezone/version:
* timezone/zdump.c, timezone/zic.c: Copy verbatim from TZDB 2024a.
2024-04-07 13:35:48 -07:00
Paul Eggert
57581acd95 Fix bsearch, qsort doc to match POSIX better
* manual/search.texi (Array Search Function):
Correct the statement about lfind’s mean runtime:
it is proportional to a number (not that number),
and this is true only if random elements are searched for.
Relax the constraint on bsearch’s array argument:
POSIX says it need not be sorted, only partially sorted.
Say that the first arg passed to bsearch’s comparison function
is the key, and the second arg is an array element, as
POSIX requires.  For bsearch and qsort, say that the
comparison function should not alter the array, as POSIX
requires.  For qsort, say that the comparison function
must define a total order, as POSIX requires, that
it should not depend on element addresses, that
the original array index can be used for stable sorts,
and that if qsort still works if memory allocation fails.
Be more consistent in calling the array elements
“elements” rather than “objects”.

Co-authored-by: Zack Weinberg <zack@owlfolio.org>
2024-04-06 10:10:32 -07:00
H.J. Lu
9e1f4aef86 x86-64: Exclude FMA4 IFUNC functions for -mapxf
When -mapxf is used to build glibc, the resulting glibc will never run
on FMA4 machines.  Exclude FMA4 IFUNC functions when -mapxf is used.
This requires GCC which defines __APX_F__ for -mapxf with commit:

1df56719bd8 x86: Define __APX_F__ for -mapxf

Reviewed-by: Sunil K Pandey <skpgkp2@gmail.com>
2024-04-06 05:03:55 -07:00
Adhemerval Zanella
c27f8763cf Reinstate generic features-time64.h
The a4ed0471d7 removed the generic version which is included by
features.h and used by Hurd.

Checked by building i686-gnu and x86_64-gnu with build-many-glibc.py.
2024-04-05 09:02:36 -03:00
Adhemerval Zanella
460d9e2dfe Cleanup __tls_get_addr on alpha/microblaze localplt.data
They are not required.

Checked with a make check for both ABIs.
2024-04-04 17:20:33 -03:00
Adhemerval Zanella
95700e7998 arm: Remove ld.so __tls_get_addr plt usage
Use the hidden alias instead.

Checked on arm-linux-gnueabihf.
2024-04-04 17:03:32 -03:00
Adhemerval Zanella
50c2be2390 aarch64: Remove ld.so __tls_get_addr plt usage
Use the hidden alias instead.

Checked on aarch64-linux-gnu.
2024-04-04 17:02:32 -03:00
Adhemerval Zanella
44ccc2465c math: x86 trunc traps when FE_INEXACT is enabled (BZ 31603)
The implementations of trunc functions using x87 floating point (i386 and
x86_64 long double only) traps when FE_INEXACT is enabled.  Although
this is a GNU extension outside the scope of the C standard, other
architectures that also support traps do not show this behavior.

The fix moves the implementation to a common one that holds any
exceptions with a 'fnclex' (libc_feholdexcept_setround_387).

Checked on x86_64-linux-gnu and i686-linux-gnu.
Reviewed-by: H.J. Lu <hjl.tools@gmail.com>
2024-04-04 14:29:28 -03:00
Adhemerval Zanella
932544efa4 math: x86 floor traps when FE_INEXACT is enabled (BZ 31601)
The implementations of floor functions using x87 floating point (i386 and
86_64 long double only) traps when FE_INEXACT is enabled.  Although
this is a GNU extension outside the scope of the C standard, other
architectures that also support traps do not show this behavior.

The fix moves the implementation to a common one that holds any
exceptions with a 'fnclex' (libc_feholdexcept_setround_387).

Checked on x86_64-linux-gnu and i686-linux-gnu.
Reviewed-by: H.J. Lu <hjl.tools@gmail.com>
2024-04-04 14:29:28 -03:00
Adhemerval Zanella
637bfc392f math: x86 ceill traps when FE_INEXACT is enabled (BZ 31600)
The implementations of ceil functions using x87 floating point (i386 and
x86_64 long double only) traps when FE_INEXACT is enabled.  Although
this is a GNU extension outside the scope of the C standard, other
architectures that also support traps do not show this behavior.

The fix moves the implementation to a common one that holds any
exceptions with a 'fnclex' (libc_feholdexcept_setround_387).

Checked on x86_64-linux-gnu and i686-linux-gnu.
Reviewed-by: H.J. Lu <hjl.tools@gmail.com>
2024-04-04 14:29:28 -03:00
Joe Ramsay
87cb1dfcd6 aarch64/fpu: Add vector variants of erfc
Reviewed-by: Szabolcs Nagy <szabolcs.nagy@arm.com>
2024-04-04 10:33:24 +01:00
Joe Ramsay
3d3a4fb8e4 aarch64/fpu: Add vector variants of tanh
Reviewed-by: Szabolcs Nagy <szabolcs.nagy@arm.com>
2024-04-04 10:33:20 +01:00
Joe Ramsay
eedbbca0bf aarch64/fpu: Add vector variants of sinh
Reviewed-by: Szabolcs Nagy <szabolcs.nagy@arm.com>
2024-04-04 10:33:16 +01:00
Joe Ramsay
8b67920528 aarch64/fpu: Add vector variants of atanh
Reviewed-by: Szabolcs Nagy <szabolcs.nagy@arm.com>
2024-04-04 10:33:12 +01:00
Joe Ramsay
81406ea3c5 aarch64/fpu: Add vector variants of asinh
Reviewed-by: Szabolcs Nagy <szabolcs.nagy@arm.com>
2024-04-04 10:33:02 +01:00
Joe Ramsay
b09fee1d21 aarch64/fpu: Add vector variants of acosh
Reviewed-by: Szabolcs Nagy <szabolcs.nagy@arm.com>
2024-04-04 10:32:58 +01:00
Joe Ramsay
bdb5705b7b aarch64/fpu: Add vector variants of cosh
Reviewed-by: Szabolcs Nagy <szabolcs.nagy@arm.com>
2024-04-04 10:32:52 +01:00
Joe Ramsay
cb5d84f1f8 aarch64/fpu: Add vector variants of erf
Reviewed-by: Szabolcs Nagy <szabolcs.nagy@arm.com>
2024-04-04 10:32:48 +01:00
Stafford Horne
3db9d208dd misc: Add support for Linux uio.h RWF_NOAPPEND flag
In Linux 6.9 a new flag is added to allow for Per-io operations to
disable append mode even if a file was opened with the flag O_APPEND.
This is done with the new RWF_NOAPPEND flag.

This caused two test failures as these tests expected the flag 0x00000020
to be unused.  Adding the flag definition now fixes these tests on Linux
6.9 (v6.9-rc1).

  FAIL: misc/tst-preadvwritev2
  FAIL: misc/tst-preadvwritev64v2

This patch adds the flag, adjusts the test and adds details to
documentation.

Link: https://lore.kernel.org/all/20200831153207.GO3265@brightrain.aerifal.cx/
Reviewed-by: Adhemerval Zanella  <adhemerval.zanella@linaro.org>
2024-04-04 09:41:27 +01:00
Alejandro Colomar
95c70fd0d4 manual: significand() uses FLT_RADIX, not 2
It's implemented using scalb(), which uses FLT_RADIX, AFAIK.

Link: <https://lore.kernel.org/linux-man/ZeYKUOKYS7G90SaV@debian/T/#mf21ab57e16b92eb6be6c7df79dc0eb43d4454056>
Reported-by: Morten Welinder <mwelinder@gmail.com>
Cc: Adhemerval Zanella Netto <adhemerval.zanella@linaro.org>
Cc: Vincent Lefevre <vincent@vinc17.net>
Cc: DJ Delorie <dj@redhat.com>
Cc: Paul Zimmermann <Paul.Zimmermann@inria.fr>
Cc: Andreas Schwab <schwab@linux-m68k.org>
Signed-off-by: Alejandro Colomar <alx@kernel.org>
Reviewed-by: DJ Delorie <dj@redhat.com>
2024-04-03 09:16:22 -03:00