The current IFUNC selection is based on microbenchmarks in glibc. It
should give the best performance for most workloads. But other choices
may have better performance for a particular workload or on the hardware
which wasn't available at the selection was made. The environment
variable, GLIBC_TUNABLES=glibc.tune.ifunc=-xxx,yyy,-zzz...., can be used
to enable CPU/ARCH feature yyy, disable CPU/ARCH feature yyy and zzz,
where the feature name is case-sensitive and has to match the ones in
cpu-features.h. It can be used by glibc developers to override the
IFUNC selection to tune for a new processor or improve performance for
a particular workload. It isn't intended for normal end users.
NOTE: the IFUNC selection may change over time. Please check all
multiarch implementations when experimenting.
Also, GLIBC_TUNABLES=glibc.tune.x86_non_temporal_threshold=NUMBER is
provided to set threshold to use non temporal store to NUMBER,
GLIBC_TUNABLES=glibc.tune.x86_data_cache_size=NUMBER to set data cache
size, GLIBC_TUNABLES=glibc.tune.x86_shared_cache_size=NUMBER to set
shared cache size.
* elf/dl-tunables.list (tune): Add ifunc,
x86_non_temporal_threshold,
x86_data_cache_size and x86_shared_cache_size.
* manual/tunables.texi: Document glibc.tune.ifunc,
glibc.tune.x86_data_cache_size, glibc.tune.x86_shared_cache_size
and glibc.tune.x86_non_temporal_threshold.
* sysdeps/unix/sysv/linux/x86/dl-sysdep.c: New file.
* sysdeps/x86/cpu-tunables.c: Likewise.
* sysdeps/x86/cacheinfo.c
(init_cacheinfo): Check and get data cache size, shared cache
size and non temporal threshold from cpu_features.
* sysdeps/x86/cpu-features.c [HAVE_TUNABLES] (TUNABLE_NAMESPACE):
New.
[HAVE_TUNABLES] Include <unistd.h>.
[HAVE_TUNABLES] Include <elf/dl-tunables.h>.
[HAVE_TUNABLES] (TUNABLE_CALLBACK (set_ifunc)): Likewise.
[HAVE_TUNABLES] (init_cpu_features): Use TUNABLE_GET to set
IFUNC selection, data cache size, shared cache size and non
temporal threshold.
* sysdeps/x86/cpu-features.h (cpu_features): Add data_cache_size,
shared_cache_size and non_temporal_threshold.
This patch makes configure require GCC 4.9 or later for building
glibc, and documents that requirement. Requiring GCC 4.9 or later
allows use of _Generic (as in tzcode). It would allow <stdatomic.h>
and _Atomic to be used as well if desired, although we need to avoid
any libatomic dependencies on any platforms. This patch is explicitly
the minimum to implement a new version requirement, with any
consequent cleanups of conditional code (not in installed headers or
files shared with gnulib etc.) to be done separately.
Tested for x86_64.
* configure.ac (libc_cv_compiler_ok): Require GCC 4.9 or later.
* configure: Regenerated.
* manual/install.texi (Tools for Compilation): Document
requirement for GCC 4.9 or later.
* INSTALL: Regenerated.
The Summary is now generated from @standards, and syntax-checking is
performed. If invalid @standards syntax is detected, summary.pl will
fail, reporting all errors. Failure and error reporting is disabled
for now, however, since much of the manual is still incomplete
wrt. header and standards annotations.
Note that the sorting order of the Summary has changed; summary.pl
respects the locale, like summary.awk did, but the use of LC_ALL=C is
introduced in the Makefile. Other notable deviations are improved
detection of the annotated elements' names, which are used for
sorting, and improved detection of the @node used to reference into
the manual. The most noticeable difference in the rendered Summary is
that entries may now contain multiple lines, one for each header and
standard combination.
summary.pl accepts a `--help' option, which details the expected
syntax of @standards. If errors are reported, the user is directed to
this feature for further information.
* manual/Makefile: Generate summary.texi with summary.pl.
Force use of the C locale. Update Perl dependency comment.
* manual/header.texi: Update reference to summary.awk.
* manual/macros.texi: Refer authors to `summary.pl --help'.
* manual/summary.awk: Remove file.
* manual/summary.pl: New file. Generate summary.texi, and
check for @standards-related syntax errors.
* manual/argp.texi: Convert header and standards @comments to
@standards.
* manual/arith.texi: Likewise.
* manual/charset.texi: Likewise.
* manual/conf.texi: Likewise.
* manual/creature.texi: Likewise.
* manual/crypt.texi: Likewise.
* manual/ctype.texi: Likewise.
* manual/debug.texi: Likewise.
* manual/errno.texi: Likewise.
* manual/filesys.texi: Likewise.
* manual/getopt.texi: Likewise.
* manual/job.texi: Likewise.
* manual/lang.texi: Likewise.
* manual/llio.texi: Likewise.
* manual/locale.texi: Likewise.
* manual/math.texi: Likewise.
* manual/memory.texi: Likewise.
* manual/message.texi: Likewise.
* manual/pattern.texi: Likewise.
* manual/pipe.texi: Likewise.
* manual/process.texi: Likewise.
* manual/resource.texi: Likewise.
* manual/search.texi: Likewise.
* manual/setjmp.texi: Likewise.
* manual/signal.texi: Likewise.
* manual/socket.texi: Likewise.
* manual/startup.texi: Likewise.
* manual/stdio.texi: Likewise.
* manual/string.texi: Likewise.
* manual/sysinfo.texi: Likewise.
* manual/syslog.texi: Likewise.
* manual/terminal.texi: Likewise.
* manual/threads.texi: Likewise.
* manual/time.texi: Likewise.
* manual/users.texi: Likewise.
Header and standards annotations are slated for standardization,
including being rendered in the description of functions, variables,
etc. (elements), and eventually required. This commit adds @standards
dummy macros so we can convert all existing annotations to the new
framework while maintaining the rendered status quo.
There needs to be a way to disambiguate annotations in lists of @*x
elements, where a common description is shared but some elements may
have different headers or standards. The @standardsx macro fills this
role by accepting an additional parameter: the name of the annotated
element.
* manual/macros.texi (@standards): New macro. Provide
placeholder for header and standards annotations.
(@standardsx): New macro. Likewise, for lists of @*x
elements.
All of the major architectures are adopting tunables as a way to add
tuning to the library, from hwcap_mask for aarch64 to HLE for s390 and
ifunc and cache geometry for x86. Given this adoption and the fact
that we don't want additional tuning knobs to be added outside of
tunables, it makes sense to enable tunables by default using this
trivial patch.
Smoke tested on x86 to ensure that tunables code was built without
specifying it as a configure flag. I have kept it as --enabled and
not changed it to --disable since we want to still keep the option of
different kinds of front-ends for tunables.
* configure.ac(--enable-tunables): Enable by default.
* configure: Regenerate.
* NEWS: Mention change.
* manual/install.texi (enable-tunables): Adjust documentation.
* INSTALL: Regenerate.
* manual/math.texi (Mathematics): Add description for _FloatN and
_FloatNx types and mentions that they are not support in glibc for
any architecture, so far.
* manual/arith.texi (wcstof, wcstold): Replace the mention to
stdlib.h with wchar.h.
(Parsing of Floats): Add descriptions for strtofN and wcstofN.
(Printing of Floats): Add description for strfromfN.
Add LD_HWCAP_MASK to tunables in preparation of it being removed from
rtld.c. This allows us to read LD_HWCAP_MASK much earlier so that it
can influence IFUNC resolution in aarch64.
This patch does not actually do anything other than read the
LD_HWCAP_MASK variable and add the tunables way to set the
LD_HWCAP_MASK, i.e. via the glibc.tune.hwcap_mask tunable. In a
follow-up patch, the _dl_hwcap_mask will be replaced with
glibc.tune.hwcap_mask to complete the transition.
* elf/dl-tunables.list: Add glibc.tune.hwcap_mask.
* scripts/gen-tunables.awk: Include dl-procinfo.h.
* manual/tunables.texi: Document glibc.tune.hwcap_mask.
The @errno macro is extended to render the canonical error string in
every documented errno error. Redundant entries and "???" are
removed. Sixty-six errors now at least contain the error string as
the description, where no description (or "???") existed before.
* manual/errno.texi: Remove redundant error strings.
* manual/macros.texi (@errno): Render the error string in
every description.
This patch adds support of preadv2 and pwritev2 which are similar to
preadv/pwritev but with an extra flag argument. As for preadv/pwritev
both interfaces are added a non-standard GNU API.
For default 'posix' implementation trying to emulate the Linux supported
flags is troublesome:
* We can not temporary change the file state of the O_DSYNC and O_SYNC
flags to emulate RWF_{D}SYNC (attempts to change the state of using
fcntl are silently ignored).
* IOCB_HIPRI requires the file opened in O_DIRECT and uses an internal
semantic not provided by any other flag (O_NONBLOCK for instance).
So default sysdeps/posix implementations fails with EOPNOTSUPP for any non
supported flag (which are none currently) calls generic preadv/pwritev.
Basically this implementation supports only preadv2 called as preadv (with
flags sets to 0).
The Linux one uses the preadv2/pwritev2 syscall if defined, otherwise it
call preadv/writev. Instead of using the previous __ASSUME_* to
unconditionally issue the syscall (and avoid building the fallback routine),
it call pread/write if the preadv2/pwritev2 syscalls fails. The idea
is just avoid adding another __ASSUME_* and checking each architecture
on every kernel bump and simplify code conditionals.
Checked on x86_64-linux-gnu and on i686-linux-gnu and a check with
run-built-tests=no on aarch64-linux-gnu, alpha-linux-gnu, arm-linux-gnueabihf,
ia64-linux-gnu, m68k-linux-gnu, microblaze-linux-gnu, mips{64,64n32}-linux-gnu,
nios2-linux-gnu, powerpc{64,64le}-linux-gnu, s390{x}-linux-gnu,
sparc{64,v9}-linux-gnu, tile{gx,pro}-linux-gnu, and sh4-linux-gnu (all using
gcc 6.3).
* NEWS: Add note about pwritev2 and preadv2 inclusion.
* misc/Makefile (routines): Add preadv2, preadv64v2, pwritev2, and
pwritev64v2.
(tests): Add tst-preadvwritev2 and tst-preadvwritev64v2.
* misc/Versions (GLIBC_2.26): Add preadv2, preadv64v2, pwritev2, and
pwritev64v2.
* misc/preadv2.c: New file.
* misc/preadv64v2.c: Likewise.
* misc/pwritev2.c: Likewise.
* misc/pwritev64v2.c: Likewise.
* misc/tst-preadvwritev2.c: Likewise.
* misc/tst-preadvwritev64v2.c: Likewise.
* manual/llio.texi: Add preadv2 and pwritev2 documentation.
* misc/sys/uio.h [__USE_GNU && !__USE_FILE_OFFSET64] (preadv2): New
prototype.
[__USE_GNU && !__USE_FILE_OFFSET64] (pwritev2): Likewise.
[__USE_GNU && __USE_FILE_OFFSET64] (preadv64v2): Likewise.
[__USE_GNU && __USE_FILE_OFFSET64] (pwritev64v2): Likewise.
* misc/tst-preadvwritev-common.c (PREADV): Define if not defined.
(PWRITEV): Likewise.
(do_test_with_offset): Use PREADV and PWRITEV macros and check for
ENOSYS.
* nptl/tst-cancel4.c (tf_pwritev2): New test.
(tf_preadv2): Likewise.
(tf_fsync): Add tf_pwritev2 and tf_preadv2.
* sysdeps/posix/preadv2.c: Likewise.
* sysdeps/posix/preadv64v2.c: Likewise.
* sysdeps/posix/pwritev2.c: Likewise.
* sysdeps/posix/pwritev64v2.c: Likewise.
* sysdeps/unix/sysv/linux/kernel-features.h: Add comment for syscall
support in kernel.
* sysdeps/unix/sysv/linux/preadv2.c: Likewise.
* sysdeps/unix/sysv/linux/preadv64v2.c: Likewise.
* sysdeps/unix/sysv/linux/pwritev2.c: Likewise.
* sysdeps/unix/sysv/linux/pwritev64v2.c: Likewise.
* sysdeps/unix/sysv/linux/preadv.c (preadv): Add libc_hidden_def.
* sysdeps/unix/sysv/linux/preadv64.c (preadv64): Likewise.
* sysdeps/unix/sysv/linux/pwritev.c (pwritev): Likewise.
* sysdeps/unix/sysv/linux/pwritev64.c (pwritev64): Likewise.
* sysdeps/unix/sysv/linux/bits/uio.h: Add supported preadv2/pwritev2
support flags on Linux.
* sysdeps/unix/sysv/linux/aarch64/libc.abilist (GLIBC_2.26): Add
preadv2, preadv64v2, pwritev2, pwritev64v2.
* sysdeps/unix/sysv/linux/alpha/libc.abilist (GLIBC_2.26): Likewise.
* sysdeps/unix/sysv/linux/arm/libc.abilist (GLIBC_2.26): Likewise.
* sysdeps/unix/sysv/linux/hppa/libc.abilist (GLIBC_2.26): Likewise.
* sysdeps/unix/sysv/linux/i386/libc.abilist (GLIBC_2.26): Likewise.
* sysdeps/unix/sysv/linux/ia64/libc.abilist (GLIBC_2.26): Likewise.
* sysdeps/unix/sysv/linux/m68k/coldfire/libc.abilist (GLIBC_2.26):
Likewise.
* sysdeps/unix/sysv/linux/m68k/m680x0/libc.abilist (GLIBC_2.26):
Likewise.
* sysdeps/unix/sysv/linux/microblaze/libc.abilist (GLIBC_2.26):
Likewise.
* sysdeps/unix/sysv/linux/mips/mips32/fpu/libc.abilist (GLIBC_2.26):
Likewise.
* sysdeps/unix/sysv/linux/mips/mips32/nofpu/libc.abilist (GLIBC_2.26):
Likewise.
* sysdeps/unix/sysv/linux/mips/mips64/n32/libc.abilist (GLIBC_2.26):
Likewise.
* sysdeps/unix/sysv/linux/mips/mips64/n64/libc.abilist (GLIBC_2.26):
Likewise.
* sysdeps/unix/sysv/linux/nios2/libc.abilist (GLIBC_2.26): Likewise.
* sysdeps/unix/sysv/linux/powerpc/powerpc32/fpu/libc.abilist
(GLIBC_2.26): Likewise.
* sysdeps/unix/sysv/linux/powerpc/powerpc32/nofpu/libc.abilist
(GLIBC_2.26): Likewise.
* sysdeps/unix/sysv/linux/powerpc/powerpc64/libc.abilist (GLIBC_2.26):
Likewise.
* sysdeps/unix/sysv/linux/powerpc/powerpc64/libc-le.abilist
(GLIBC_2.26): Likewise.
* sysdeps/unix/sysv/linux/s390/s390-32/libc.abilist (GLIBC_2.26):
Likewise.
* sysdeps/unix/sysv/linux/s390/s390-64/libc.abilist (GLIBC_2.26):
Likewise.
* sysdeps/unix/sysv/linux/sh/libc.abilist (GLIBC_2.26): Likewise.
* sysdeps/unix/sysv/linux/sparc/sparc32/libc.abilist (GLIBC_2.26):
Likewise.
* sysdeps/unix/sysv/linux/sparc/sparc64/libc.abilist (GLIBC_2.26):
Likewise.
* sysdeps/sysv/linux/tile/tilegx/tilegx32/libc.abilist (GLIBC_2.26):
Likewise.
* sysdeps/sysv/linux/tile/tilegx/tilegx64/libc.abilist (GLIBC_2.26):
Likewise.
* sysdeps/unix/sysv/linux/tile/tilepro/libc.abilist (GLIBC_2.26):
Likewise.
* sysdeps/unix/sysv/linux/x86_64/64/libc.abilist (GLIBC_2.26):
Likewise.
* sysdeps/unix/sysv/linux/x86_64/x32/libc.abilist (GLIBC_2.26):
Likewise.
As described in BZ#21398 (close as dup of 21393) report current
freopen implementation fails when one tries to freopen STDIN_FILENO,
STDOUT_FILENO, or STDERR_FILENO. Although on bug report the
discussion leads to argue if a close followed by a freopen on the
standard file is a valid operation, the underlying issue is not
really the check for dup3 returned value, but rather calling it
if the returned file descriptor is equal as the input one.
So for a quality of implementation this patch avoid calling dup3
for the aforementioned case. It also adds a dup3 error case check
for the two possible failures, with one being Linux only: EINTR and
EBUSY. The EBUSY issue is better explained on this stackoverflow
thread [1], but in a short it is due the internal Linux
implementation which allows a race condition window for dup2 due
the logic dissociation of file descriptor allocation and actual
VFS 'install' operation. For both outliers failures all allocated
memory is freed and a NULL FILE* is returned.
With this patch the example on BZ#21398 is now actually possible
(I used as the testcase for the bug report). Checked on
x86_64-linux-gnu.
[BZ #21393]
* libio/freopen.c (freopen): Avoid dup already opened file descriptor
and add a check for dup3 failure.
* libio/freopen64.c (freopen64): Likewise.
* libio/tst-freopen.c (do_test): Rename to do_test_basic and use
libsupport.
(do_test_bz21398): New test.
* manual/stdio.texi (freopen): Add documentation of EBUSY failure.
[1] http://stackoverflow.com/questions/23440216/race-condition-when-using-dup2
errno.texi documents error macros, their values, and error strings in
Texinfo @comments, some of which are also used for @standards. The
purpose of this commit is to separate the standards from the error
strings so that both the @standards conversion script picks up clean
@standards and the errno documentation framework is improved.
The error names, values, and messages are consolidated in a new custom
macro, @errno. It is not clear that scripts within the sources rely
on the special Texinfo @comment-based format to generate files used
throughout the library, so the definition of @errno in macros.texi now
provides a comment indicating the dependency. The dependent scripts
are updated to use @errno, which also simplifies them a bit. The
files those scripts generate were verified to be unchanged.
The @errno macro is not visibly rendered in any way at this time, but
it does use an @cindex command to add the error string to the Concept
Index, to facilitate searching on error messages.
* manual/errno.texi: Convert @comment-based errno
documentation to @errno.
* manual/macros.texi (@errno): New macro. Consolidate errors,
their values, and messages, adding the error string to the
Concept Index. Provide a warning in the comment about
external (to the manual) dependencies.
* sysdeps/gnu/errlist.awk: Use @errno instead of @comments.
* sysdeps/mach/hurd/errnos.awk: Likewise.
The conversion script will convert these annotations, but the
replacement Summary-generation script won't catch them because @items
in @tables are not generally considered annotatable, causing them to
be skipped over (or cause errors). Using @vtable ensures their
continued presence in the Summary, with the added benefit that Texinfo
will also automatically include them in the Variable and Constant
Macro index now.
* manual/conf.texi: Convert @tables of annotated @items to
@vtables.
* manual/lang.texi: Likewise.
* manual/pattern.texi: Likewise.
* manual/resource.texi: Likewise.
* manual/socket.texi: Likewise.
This commit handles exceptional cases of invalid syntax for the
@standards conversion script.
* manual/crypt.texi: Move a comment out of an @*x list.
* manual/filesys.texi: Refactor some comments, one of which
looks like a standard. Fix incorrectly separated standards.
* manual/locale.texi: Invert an annotation.
* manual/resource.texi: Fix incorrectly separated standards.
* manual/time.texi: Refactor a @vtable that obscures an
annotation.
* manual/users.texi: Refactor multiple headers to occupy a
single @comment.
This macro is defined by TS 18661-3 for supporting the _FloatN and
_FloatNx types, as well as the functions suffixed with fN.
* bits/libc-header-start.h:
(__GLIBC_USE_IEC_60559_TYPES_EXT): New macro.
* include/features.h: Describe __STDC_WANT_IEC_60559_TYPES_EXT__.
* manual/creature.texi: Likewise.
Simplify the Linux accept4 implementation based on the assumption
that it is available in some way. __ASSUME_ACCEPT4_SOCKETCALL was
previously unused, so remove it.
For ia64, the accept4 system call (and socket call) were backported
in kernel version 3.2.18. Reflect this in the installation
instructions.
They only modify the state in the dirstream argument, and we
generally do not treat this as a reason to mark a function as
not thread-safe. For an example, see random_r, which is marked
as thread-safe even though the random state is not protected
by a lock.
glibc's implementation of getopt includes code to parse an environment
variable named _XXX_GNU_nonoption_argv_flags_ (where XXX is the
current process's PID in decimal); but all of it has been #ifdefed out
since 2001, with no official way to turn it back on.
According to commentary in our config.h.in, bash version 2.0 set this
environment variable to indicate argv elements that were the result of
glob expansion and therefore should not be treated as options, but the
feature was "disabled later" because "it caused problems". According
to bash's CHANGES file, "later" was release 2.01; it gives no more
detail about what the problems were.
Version 2.0 of bash was released on the last day of 1996, and version
2.01 in June of 1997. Twenty years later, I think it is safe to
assume that this environment variable isn't coming back.
* config.h.in (USE_NONOPTION_FLAGS): Remove.
* csu/init-first.c: Remove all #ifdef USE_NONOPTION_FLAGS blocks.
* sysdeps/mach/hurd/i386/init-first.c: Likewise.
* posix/getopt_int.h: Likewise.
* posix/getopt.c: Likewise. Also remove SWAP_FLAGS and the
__libc_argc and __libc_argv externs, which were only used by
#ifdef USE_NONOPTION_FLAGS blocks.
* posix/getopt_init.c: Remove file.
* posix/Makefile (routines): Remove getopt_init.
* include/getopt.h: Don't declare __getopt_initialize_environment.
* manual/getopt.texi: Remove mention of USE_NONOPTION_FLAGS in
a comment.
manual/libm-err-tab.pl contains a hardcoded list of libm functions for
which ulps are listed in the manual, and another hardcoded list in a
comment of functions deliberately excluded because of an expected lack
of ulps (and the two together are not in fact an exhaustive list of
libm functions tested through the libm-test machinery).
This patch removes these hardcoded lists, so eliminating this from the
places needing updating when a new libm function is added. Instead,
ulps are tabulated for functions for which they are seen in
libm-test-ulps files, in alphabetical order. The pseudo-function
names such as *_downward and *_vlen* are excluded since they are
excluded from the existing lists, and the description in the manual is
updated to explain how those entries are excluded and if a function is
not listed at all it does not have known errors.
Tested for x86_64.
* manual/libm-err-tab.pl (@all_functions): Change to
%all_functions. Initialize as empty.
(parse_ulps): Add to %all_functions based on functions found in
ulps files. Ignore results for non-default rounding modes and
vector functions.
(print_platforms): Use %all_platforms.
* manual/math.texi (Errors in Math Functions): Document omissions
from the table.
Create a new node for tunables documentation and add notes for the
malloc tunables.
* manual/tunables.texi: New chapter.
* manual/Makefile (chapters): Add it.
* manual/probes.texi (@node): Point to the Tunables chapter.
At the GNU Tools Cauldron 2016, the state of the current tunables
patchset was considered OK with the addition of a way to select the
frontend to be used for the tunables. That is, to avoid being locked
in to one type of frontend initially, it should be possible to build
tunables with a different frontend with something as simple as a
configure switch.
To that effect, this patch enhances the --enable-tunables option to
accept more values than just 'yes' or 'no'. The current frontend (and
default when enable-tunables is 'yes') is called 'valstring', to
select the frontend where a single environment variable is set to a
colon-separated value string. More such frontends can be added in
future.
* Makeconfig (have-tunables): Check for non-negative instead
of positive.
* configure.ac: Add 'valstring' as a valid value for
--enable-tunables.
* configure: Regenerate.
* elf/Makefile (have-tunables): Check for non-negative instead
of positive.
(CPPFLAGS-dl-tunables.c): Define TUNABLES_FRONTEND for
dl-tunables.c.
* elf/dl-tunables.c (GLIBC_TUNABLES): Define only when
TUNABLES_FRONTEND == TUNABLES_FRONTEND_valstring.
(tunables_strdup): Likewise.
(disable_tunables): Likewise.
(parse_tunables): Likewise.
(__tunables_init): Process GLIBC_TUNABLES envvar only when.
TUNABLES_FRONTEND == TUNABLES_FRONTEND_valstring.
* elf/dl-tunables.h (TUNABLES_FRONTEND_valstring): New macro.
(TUNABLES_FRONTEND_yes): New macro, define as
TUNABLES_FRONTEND_valstring by default.
* manual/install.texi: Document new acceptable values for
--enable-tunables.
* INSTALL: Regenerate.
The tunables framework allows us to uniformly manage and expose global
variables inside glibc as switches to users. tunables/README has
instructions for glibc developers to add new tunables.
Tunables support can be enabled by passing the --enable-tunables
configure flag to the configure script. This patch only adds a
framework and does not pose any limitations on how tunable values are
read from the user. It also adds environment variables used in malloc
behaviour tweaking to the tunables framework as a PoC of the
compatibility interface.
* manual/install.texi: Add --enable-tunables option.
* INSTALL: Regenerate.
* README.tunables: New file.
* Makeconfig (CPPFLAGS): Define TOP_NAMESPACE.
(before-compile): Generate dl-tunable-list.h early.
* config.h.in: Add HAVE_TUNABLES.
* config.make.in: Add have-tunables.
* configure.ac: Add --enable-tunables option.
* configure: Regenerate.
* csu/init-first.c (__libc_init_first): Move
__libc_init_secure earlier...
* csu/init-first.c (LIBC_START_MAIN):... to here.
Include dl-tunables.h, libc-internal.h.
(LIBC_START_MAIN) [!SHARED]: Initialize tunables for static
binaries.
* elf/Makefile (dl-routines): Add dl-tunables.
* elf/Versions (ld): Add __tunable_set_val to GLIBC_PRIVATE
namespace.
* elf/dl-support (_dl_nondynamic_init): Unset MALLOC_CHECK_
only when !HAVE_TUNABLES.
* elf/rtld.c (process_envvars): Likewise.
* elf/dl-sysdep.c [HAVE_TUNABLES]: Include dl-tunables.h
(_dl_sysdep_start): Call __tunables_init.
* elf/dl-tunable-types.h: New file.
* elf/dl-tunables.c: New file.
* elf/dl-tunables.h: New file.
* elf/dl-tunables.list: New file.
* malloc/tst-malloc-usable-static.c: New test case.
* malloc/Makefile (tests-static): Add it.
* malloc/arena.c [HAVE_TUNABLES]: Include dl-tunables.h.
Define TUNABLE_NAMESPACE.
(DL_TUNABLE_CALLBACK (set_mallopt_check)): New function.
(DL_TUNABLE_CALLBACK_FNDECL): New macro. Use it to define
callback functions.
(ptmalloc_init): Set tunable values.
* scripts/gen-tunables.awk: New file.
* sysdeps/mach/hurd/dl-sysdep.c: Include dl-tunables.h.
(_dl_sysdep_start): Call __tunables_init.
TS 18661-1 defines fromfp functions (fromfp, fromfpx, ufromfp,
ufromfpx, and float and long double variants) to convert from
floating-point to an integer type with any signedness and any given
width up to that of intmax_t, in any of the five IEEE rounding modes
(the usual four for binary floating point, plus rounding to nearest
with ties rounding away from zero), with control of whether in-range
non-integer values should result in the "inexact" exception being
raised. This patch implements these functions for glibc.
These implementations are (apart from raising exceptions) pure integer
implementations; it's entirely possible optimized versions could be
devised for some architectures. A common math/fromfp.h header
provides various common helper code that can readily be shared between
the implementations for different types. For each type, the bulk of
the implementation is also shared between the four functions, with
wrappers that define UNSIGNED and INEXACT macros appropriately before
including the main implementation.
As the functions return intmax_t and uintmax_t without math.h being
allowed to expose those typedef names, they are declared using
__intmax_t and __uintmax_t as obtained from <bits/types.h>.
The FP_INT_* rounding direction macros are defined as ascending
integers in the order the names are listed in the TS; I see no
significant value in allowing architectures to vary the values of
them.
The libm-test machinery is duly adapted to handle unsigned int
arguments, and intmax_t and uintmax_t results. Because each test
input is generally tested for four functions, five rounding modes and
several different widths, the libm-test.inc additions are very large.
Thus, the diffs in the body of this message exclude the libm-test.inc
changes, with the full patch being attached gzipped. The bulk of the
new tests were generated (expanded from a test input plus rounding
results and information about where it lies in the relevant interval
between integers, to libm-test tests for all relevant combinations of
function, rounding direction and width) by a script that's included in
the patch as math/gen-fromfp-tests.py (input data
math/gen-fromfp-tests-inputs); as an ad hoc script that's not really
expected to be rerun, it's not very polished, but it's at least
plausibly useful for adding any further tests for these functions in
future. I may split the libm-test tests up by function in future (so
both libm-test.inc and auto-libm-test-out are split into separate
files, and the tests for each function are also built and run
separately), but not for 2.25.
For no obvious reason, adding tgmath tests for the new functions
resulted in -Wuninitialized errors from test-tgmath.c about the
variable i being used uninitialized. Those errors were correct - the
variable is read by the frexp version in test-tgmath.c (where real
frexp would write through that pointer instead of reading it) - but I
don't know why this patch would result in the pre-existing issue being
newly detected. The patch initializes the variable to avoid those
errors.
With these changes, glibc 2.25 should have all the library features
from TS 18661-1 other than the functions that round result to narrower
type (and constant rounding directions, but I'm considering those
mainly a compiler feature not a library one).
Tested for x86_64, x86, mips64 and powerpc.
* math/bits/mathcalls.h [__GLIBC_USE (IEC_60559_BFP_EXT)]
(fromfp): New declaration.
[__GLIBC_USE (IEC_60559_BFP_EXT)] (fromfpx): Likewise.
[__GLIBC_USE (IEC_60559_BFP_EXT)] (ufromfp): Likewise.
[__GLIBC_USE (IEC_60559_BFP_EXT)] (ufromfpx): Likewise.
* math/tgmath.h (__TGMATH_TERNARY_FIRST_REAL_RET_ONLY): New macro.
[__GLIBC_USE (IEC_60559_BFP_EXT)] (fromfp): Likewise.
[__GLIBC_USE (IEC_60559_BFP_EXT)] (ufromfp): Likewise.
[__GLIBC_USE (IEC_60559_BFP_EXT)] (fromfpx): Likewise.
[__GLIBC_USE (IEC_60559_BFP_EXT)] (ufromfpx): Likewise.
* math/math.h: Include <bits/types.h>.
[__GLIBC_USE (IEC_60559_BFP_EXT)] (FP_INT_UPWARD): New enum
constant and macro.
(FP_INT_DOWNWARD): Likewise.
(FP_INT_TOWARDZERO): Likewise.
(FP_INT_TONEARESTFROMZERO): Likewise.
(FP_INT_TONEAREST): Likewise.
* math/Versions (fromfp): New libm symbol at version GLIBC_2.25.
(fromfpf): Likewise.
(fromfpl): Likewise.
(ufromfp): Likewise.
(ufromfpf): Likewise.
(ufromfpl): Likewise.
(fromfpx): Likewise.
(fromfpxf): Likewise.
(fromfpxl): Likewise.
(ufromfpx): Likewise.
(ufromfpxf): Likewise.
(ufromfpxl): Likewise.
* math/Makefile (libm-calls): Add s_fromfpF, s_ufromfpF,
s_fromfpxF and s_ufromfpxF.
* math/gen-fromfp-tests.py: New file.
* math/gen-fromfp-tests-inputs: Likewise.
* math/libm-test.inc: Include <stdint.h>
(check_intmax_t): New function.
(check_uintmax_t): Likewise.
(struct test_fiu_M_data): New type.
(struct test_fiu_U_data): Likewise.
(RUN_TEST_fiu_M): New macro.
(RUN_TEST_LOOP_fiu_M): Likewise.
(RUN_TEST_fiu_U): Likewise.
(RUN_TEST_LOOP_fiu_U): Likewise.
(fromfp_test_data): New array.
(fromfp_test): New function.
(fromfpx_test_data): New array.
(fromfpx_test): New function.
(ufromfp_test_data): New array.
(ufromfp_test): New function.
(ufromfpx_test_data): New array.
(ufromfpx_test): New function.
(main): Call fromfp_test, fromfpx_test, ufromfp_test and
ufromfpx_test.
* math/gen-libm-test.pl (parse_args): Handle u, M and U descriptor
characters.
* math/test-tgmath-ret.c: Include <stdint.h>.
(rm): New variable.
(width): Likewise.
(CHECK_RET_CONST_TYPE): Take extra arguments and pass them to
called function.
(CHECK_RET_CONST_FLOAT): Take extra arguments and pass them to
CHECK_RET_CONST_TYPE.
(CHECK_RET_CONST_DOUBLE): Likewise.
(CHECK_RET_CONST_LDOUBLE): Likewise.
(CHECK_RET_CONST): Take extra arguments and pass them to calls
macros.
(fromfp): New CHECK_RET_CONST call.
(ufromfp): Likewise.
(fromfpx): Likewise.
(ufromfpx): Likewise.
(do_test): Call check_return_fromfp, check_return_ufromfp,
check_return_fromfpx and check_return_ufromfpx.
* math/test-tgmath.c: Include <stdint.h>
(NCALLS): Increase to 138.
(F(compile_test)): Initialize i. Call fromfp functions.
(F(fromfp)): New function.
(F(fromfpx)): Likewise.
(F(ufromfp)): Likewise.
(F(ufromfpx)): Likewise.
* manual/arith.texi (Rounding Functions): Document FP_INT_UPWARD,
FP_INT_DOWNWARD, FP_INT_TOWARDZERO, FP_INT_TONEARESTFROMZERO,
FP_INT_TONEAREST, fromfp, fromfpf, fromfpl, ufromfp, ufromfpf,
ufromfpl, fromfpx, fromfpxf, fromfpxl, ufromfpx, ufromfpxf and
ufromfpxl.
* manual/libm-err-tab.pl (@all_functions): Add fromfp, fromfpx,
ufromfp and ufromfpx.
* math/fromfp.h: New file.
* sysdeps/ieee754/dbl-64/s_fromfp.c: Likewise.
* sysdeps/ieee754/dbl-64/s_fromfp_main.c: Likewise.
* sysdeps/ieee754/dbl-64/s_fromfpx.c: Likewise.
* sysdeps/ieee754/dbl-64/s_ufromfp.c: Likewise.
* sysdeps/ieee754/dbl-64/s_ufromfpx.c: Likewise.
* sysdeps/ieee754/flt-32/s_fromfpf.c: Likewise.
* sysdeps/ieee754/flt-32/s_fromfpf_main.c: Likewise.
* sysdeps/ieee754/flt-32/s_fromfpxf.c: Likewise.
* sysdeps/ieee754/flt-32/s_ufromfpf.c: Likewise.
* sysdeps/ieee754/flt-32/s_ufromfpxf.c: Likewise.
* sysdeps/ieee754/ldbl-128/s_fromfpl.c: Likewise.
* sysdeps/ieee754/ldbl-128/s_fromfpl_main.c: Likewise.
* sysdeps/ieee754/ldbl-128/s_fromfpxl.c: Likewise.
* sysdeps/ieee754/ldbl-128/s_ufromfpl.c: Likewise.
* sysdeps/ieee754/ldbl-128/s_ufromfpxl.c: Likewise.
* sysdeps/ieee754/ldbl-128ibm/s_fromfpl.c: Likewise.
* sysdeps/ieee754/ldbl-128ibm/s_fromfpl_main.c: Likewise.
* sysdeps/ieee754/ldbl-128ibm/s_fromfpxl.c: Likewise.
* sysdeps/ieee754/ldbl-128ibm/s_ufromfpl.c: Likewise.
* sysdeps/ieee754/ldbl-128ibm/s_ufromfpxl.c: Likewise.
* sysdeps/ieee754/ldbl-96/s_fromfpl.c: Likewise.
* sysdeps/ieee754/ldbl-96/s_fromfpl_main.c: Likewise.
* sysdeps/ieee754/ldbl-96/s_fromfpxl.c: Likewise.
* sysdeps/ieee754/ldbl-96/s_ufromfpl.c: Likewise.
* sysdeps/ieee754/ldbl-96/s_ufromfpxl.c: Likewise.
* sysdeps/ieee754/ldbl-opt/Makefile (libnldbl-calls): Add fromfp,
ufromfp, fromfpx and ufromfpx.
(CFLAGS-nldbl-fromfp.c): New variable.
(CFLAGS-nldbl-fromfpx.c): Likewise.
(CFLAGS-nldbl-ufromfp.c): Likewise.
(CFLAGS-nldbl-ufromfpx.c): Likewise.
* sysdeps/ieee754/ldbl-opt/nldbl-compat.h: Include <stdint.h>.
* sysdeps/ieee754/ldbl-opt/nldbl-fromfp.c: New file.
* sysdeps/ieee754/ldbl-opt/nldbl-fromfpx.c: Likewise.
* sysdeps/ieee754/ldbl-opt/nldbl-ufromfp.c: Likewise.
* sysdeps/ieee754/ldbl-opt/nldbl-ufromfpx.c: Likewise.
* sysdeps/nacl/libm.abilist: Update.
* sysdeps/unix/sysv/linux/aarch64/libm.abilist: Likewise.
* sysdeps/unix/sysv/linux/alpha/libm.abilist: Likewise.
* sysdeps/unix/sysv/linux/arm/libm.abilist: Likewise.
* sysdeps/unix/sysv/linux/hppa/libm.abilist: Likewise.
* sysdeps/unix/sysv/linux/i386/libm.abilist: Likewise.
* sysdeps/unix/sysv/linux/ia64/libm.abilist: Likewise.
* sysdeps/unix/sysv/linux/m68k/coldfire/libm.abilist: Likewise.
* sysdeps/unix/sysv/linux/m68k/m680x0/libm.abilist: Likewise.
* sysdeps/unix/sysv/linux/microblaze/libm.abilist: Likewise.
* sysdeps/unix/sysv/linux/mips/mips32/libm.abilist: Likewise.
* sysdeps/unix/sysv/linux/mips/mips64/libm.abilist: Likewise.
* sysdeps/unix/sysv/linux/nios2/libm.abilist: Likewise.
* sysdeps/unix/sysv/linux/powerpc/powerpc32/fpu/libm.abilist:
Likewise.
* sysdeps/unix/sysv/linux/powerpc/powerpc32/nofpu/libm.abilist:
Likewise.
* sysdeps/unix/sysv/linux/powerpc/powerpc64/libm-le.abilist:
Likewise.
* sysdeps/unix/sysv/linux/powerpc/powerpc64/libm.abilist:
Likewise.
* sysdeps/unix/sysv/linux/s390/s390-32/libm.abilist: Likewise.
* sysdeps/unix/sysv/linux/s390/s390-64/libm.abilist: Likewise.
* sysdeps/unix/sysv/linux/sh/libm.abilist: Likewise.
* sysdeps/unix/sysv/linux/sparc/sparc32/libm.abilist: Likewise.
* sysdeps/unix/sysv/linux/sparc/sparc64/libm.abilist: Likewise.
* sysdeps/unix/sysv/linux/tile/tilegx/tilegx32/libm.abilist:
Likewise.
* sysdeps/unix/sysv/linux/tile/tilegx/tilegx64/libm.abilist:
Likewise.
* sysdeps/unix/sysv/linux/tile/tilepro/libm.abilist: Likewise.
* sysdeps/unix/sysv/linux/x86_64/64/libm.abilist: Likewise.
* sysdeps/unix/sysv/linux/x86_64/x32/libm.abilist: Likewise.
This adds =all and =strong, with obvious semantics, defaulting to off.
We don't validate the value of the option yet: that's in a later patch.
Nor do we use it for anything at this stage.
We differentiate between 'the compiler understands -fstack-protector'
and 'the user wanted -fstack-protector' so that we can pass
-fno-stack-protector in appropriate places even if the user didn't want
to turn on -fstack-protector for other parts. (This helps us overcome
another existing limitation, that glibc doesn't work with GCCs hacked
to pass in -fstack-protector by default.)
We also arrange to set the STACK_PROTECTOR_LEVEL #define to a value
appropriate for the stack-protection level in use for each file in
particular.
This patch updates texinfo.tex and various miscellaneous scripts to
their latest upstream versions. (There may be another update in early
January to bring in 2017 copyright dates, if the upstream versions get
updated with such dates promptly.)
Tested for x86_64.
* manual/texinfo.tex: Update to version 2016-09-18.18 with
trailing whitespace removed.
* scripts/config.guess: Update to version 2016-10-02.
* scripts/config.sub: Update to version 2016-11-19.
* scripts/install-sh: Update to version 2016-01-11.22.
* scripts/mkinstalldirs: Update to version 2016-01-11.22.
* scripts/move-if-change: Update to version 2016-01-11 22:04.
Texinfo @vindex commands add entries to the Variable and Constant
Macro Index. Similarly, @items in @vtables are automatically indexed.
A number of @tables exist where all @items are @vindexed or all @items
are variables, but not indexed, suggesting an optimization by
converting such @tables to @vtables and dropping the @vindex.
Using a @vtable provides a context for processing @items whereby it
can be known the @items should have header and standards annotations.
This commit converts @tables of such @items to @vtables in order to
establish a framework for automated processing.
A pleasant consequence of these changes is that @items previously
lacking a @vindex are present in the Variable and Constant Macro Index
now. @vindex entries previously detected by summary.awk will still be
detected as @items with appropriate annotations.
The @vtable of the NSS databases is converted to a @table because 1)
those @items are not variables (and will no longer appear in the
Variable and Constant Macro Index) and 2) they do not need header and
standards annotations, so the incorrect context is fixed.
* manual/nss.texi: Change incorrect @vtable to @table.
* manual/arith.texi: Convert @tables of variables to @vtables
and remove unnecessary indexing.
* manual/filesys.texi: Likewise.
* manual/llio.texi: Likewise.
* manual/memory.texi: Likewise.
* manual/process.texi: Likewise.
* manual/resource.texi: Likewise.
* manual/search.texi: Likewise.
* manual/signal.texi: Likewise.
* manual/socket.texi: Likewise.
* manual/stdio.texi: Likewise.
* manual/sysinfo.texi: Likewise.
* manual/syslog.texi: Likewise.
* manual/terminal.texi: Likewise.
* manual/time.texi: Likewise.
* manual/users.texi: Likewise.
TS 18661-1 defines roundeven functions that round a floating-point
number to the nearest integer, in that floating-point type, with ties
rounding to even (whereas the round functions round ties away from
zero). As with other such functions, they raise no exceptions apart
from "invalid" for signaling NaNs. There was a previous user request
for this functionality in glibc in
<https://sourceware.org/ml/libc-help/2015-02/msg00005.html>.
This patch implements these functions for glibc. The implementations
use integer bit-manipulation (or roundeven on the high and low parts,
in the IBM long double case). It's possible that there may be faster
approaches on some architectures (in particular, on AArch64 the frintn
instruction should do exactly what's required); I'll leave it to
architecture maintainers or others interested to implement such
architecture-specific versions if desired. (Where architectures have
instructions to round to nearest integer in the current rounding mode,
implementations saving and restoring the rounding mode - and dealing
with exceptions if those instructions generate "inexact" - are also
possible, though their performance depends on the cost of manipulating
exceptions / rounding mode state.)
Tested for x86_64, x86, mips64 and powerpc.
* math/bits/mathcalls.h [__GLIBC_USE (IEC_60559_BFP_EXT)]
(roundeven): New declaration.
* math/tgmath.h [__GLIBC_USE (IEC_60559_BFP_EXT)] (roundeven): New
macro.
* math/Versions (roundeven): New libm symbol at version
GLIBC_2.25.
(roundevenf): Likewise.
(roundevenl): Likewise.
* math/Makefile (libm-calls): Add s_roundevenF.
* math/libm-test.inc (roundeven_test_data): New array.
(roundeven_test): New function.
(main): Call roundeven_test.
* math/test-tgmath.c (NCALLS): Increase to 134.
(F(compile_test)): Call roundeven.
(F(roundeven)): New function.
* manual/arith.texi (Rounding Functions): Document roundeven,
roundevenf and roundevenl.
* manual/libm-err-tab.pl (@all_functions): Add roundeven.
* include/math.h (roundeven): Use libm_hidden_proto.
* sysdeps/ieee754/dbl-64/s_roundeven.c: New file.
* sysdeps/ieee754/dbl-64/wordsize-64/s_roundeven.c: Likewise.
* sysdeps/ieee754/flt-32/s_roundevenf.c: Likewise.
* sysdeps/ieee754/ldbl-128/s_roundevenl.c: Likewise.
* sysdeps/ieee754/ldbl-128ibm/s_roundevenl.c: Likewise.
* sysdeps/ieee754/ldbl-96/s_roundevenl.c: Likewise.
* sysdeps/ieee754/ldbl-opt/Makefile (libnldbl-calls): Add
roundeven.
(CFLAGS-nldbl-roundeven.c): New variable.
* sysdeps/ieee754/ldbl-opt/nldbl-roundeven.c: New file.
* sysdeps/nacl/libm.abilist: Update.
* sysdeps/unix/sysv/linux/aarch64/libm.abilist: Likewise.
* sysdeps/unix/sysv/linux/alpha/libm.abilist: Likewise.
* sysdeps/unix/sysv/linux/arm/libm.abilist: Likewise.
* sysdeps/unix/sysv/linux/hppa/libm.abilist: Likewise.
* sysdeps/unix/sysv/linux/i386/libm.abilist: Likewise.
* sysdeps/unix/sysv/linux/ia64/libm.abilist: Likewise.
* sysdeps/unix/sysv/linux/m68k/coldfire/libm.abilist: Likewise.
* sysdeps/unix/sysv/linux/m68k/m680x0/libm.abilist: Likewise.
* sysdeps/unix/sysv/linux/microblaze/libm.abilist: Likewise.
* sysdeps/unix/sysv/linux/mips/mips32/libm.abilist: Likewise.
* sysdeps/unix/sysv/linux/mips/mips64/libm.abilist: Likewise.
* sysdeps/unix/sysv/linux/nios2/libm.abilist: Likewise.
* sysdeps/unix/sysv/linux/powerpc/powerpc32/fpu/libm.abilist:
Likewise.
* sysdeps/unix/sysv/linux/powerpc/powerpc32/nofpu/libm.abilist:
Likewise.
* sysdeps/unix/sysv/linux/powerpc/powerpc64/libm-le.abilist:
Likewise.
* sysdeps/unix/sysv/linux/powerpc/powerpc64/libm.abilist:
Likewise.
* sysdeps/unix/sysv/linux/s390/s390-32/libm.abilist: Likewise.
* sysdeps/unix/sysv/linux/s390/s390-64/libm.abilist: Likewise.
* sysdeps/unix/sysv/linux/sh/libm.abilist: Likewise.
* sysdeps/unix/sysv/linux/sparc/sparc32/libm.abilist: Likewise.
* sysdeps/unix/sysv/linux/sparc/sparc64/libm.abilist: Likewise.
* sysdeps/unix/sysv/linux/tile/tilegx/tilegx32/libm.abilist:
Likewise.
* sysdeps/unix/sysv/linux/tile/tilegx/tilegx64/libm.abilist:
Likewise.
* sysdeps/unix/sysv/linux/tile/tilepro/libm.abilist: Likewise.
* sysdeps/unix/sysv/linux/x86_64/64/libm.abilist: Likewise.
* sysdeps/unix/sysv/linux/x86_64/x32/libm.abilist: Likewise.
TS 18661-1 says that "Whether a signaling NaN input causes a domain
error is implementation-defined.". Considering it a domain error
would (given glibc's math_errhandling definition) mean setting errno
to EDOM. glibc consistently does not set errno for sNaN inputs
(unless it does so for qNaN as well, i.e. iseqsig), so this patch adds
documentation of the implementation-defined choice not to treat this
case as a domain error.
* manual/arith.texi (Math Error Reporting): Document that sNaN
arguments are not considered domain errors.
explicit_bzero(s, n) is the same as memset(s, 0, n), except that the
compiler is not allowed to delete a call to explicit_bzero even if the
memory pointed to by 's' is dead after the call. Right now, this effect
is achieved externally by having explicit_bzero be a function whose
semantics are unknown to the compiler, and internally, with a no-op
asm statement that clobbers memory. This does mean that small
explicit_bzero operations cannot be expanded inline as small memset
operations can, but on the other hand, small memset operations do get
deleted by the compiler. Hopefully full compiler support for
explicit_bzero will happen relatively soon.
There are two new tests: test-explicit_bzero.c verifies the
visible semantics in the same way as the existing test-bzero.c,
and tst-xbzero-opt.c verifies the not-being-optimized-out property.
The latter is conceptually based on a test written by Matthew Dempsky
for the OpenBSD regression suite.
The crypt() implementation has an immediate use for this new feature.
We avoid having to add a GLIBC_PRIVATE alias for explicit_bzero
by running all of libcrypt's calls through the fortified variant,
__explicit_bzero_chk, which is in the impl namespace anyway. Currently
I'm not aware of anything in libc proper that needs this, but the
glue is all in place if it does become necessary. The legacy DES
implementation wasn't bothering to clear its buffers, so I added that,
mostly for consistency's sake.
* string/explicit_bzero.c: New routine.
* string/test-explicit_bzero.c, string/tst-xbzero-opt.c: New tests.
* string/Makefile (routines, strop-tests, tests): Add them.
* string/test-memset.c: Add ifdeffage for testing explicit_bzero.
* string/string.h [__USE_MISC]: Declare explicit_bzero.
* debug/explicit_bzero_chk.c: New routine.
* debug/Makefile (routines): Add it.
* debug/tst-chk1.c: Test fortification of explicit_bzero.
* string/bits/string3.h: Fortify explicit_bzero.
* manual/string.texi: Document explicit_bzero.
* NEWS: Mention addition of explicit_bzero.
* crypt/crypt-entry.c (__crypt_r): Clear key-dependent intermediate
data before returning, using explicit_bzero.
* crypt/md5-crypt.c (__md5_crypt_r): Likewise.
* crypt/sha256-crypt.c (__sha256_crypt_r): Likewise.
* crypt/sha512-crypt.c (__sha512_crypt_r): Likewise.
* include/string.h: Redirect internal uses of explicit_bzero
to __explicit_bzero_chk[_internal].
* string/Versions [GLIBC_2.25]: Add explicit_bzero.
* debug/Versions [GLIBC_2.25]: Add __explicit_bzero_chk.
* sysdeps/arm/nacl/libc.abilist
* sysdeps/unix/sysv/linux/aarch64/libc.abilist
* sysdeps/unix/sysv/linux/alpha/libc.abilist
* sysdeps/unix/sysv/linux/arm/libc.abilist
* sysdeps/unix/sysv/linux/hppa/libc.abilist
* sysdeps/unix/sysv/linux/i386/libc.abilist
* sysdeps/unix/sysv/linux/ia64/libc.abilist
* sysdeps/unix/sysv/linux/m68k/coldfire/libc.abilist
* sysdeps/unix/sysv/linux/m68k/m680x0/libc.abilist
* sysdeps/unix/sysv/linux/microblaze/libc.abilist
* sysdeps/unix/sysv/linux/mips/mips32/fpu/libc.abilist
* sysdeps/unix/sysv/linux/mips/mips32/nofpu/libc.abilist
* sysdeps/unix/sysv/linux/mips/mips64/n32/libc.abilist
* sysdeps/unix/sysv/linux/mips/mips64/n64/libc.abilist
* sysdeps/unix/sysv/linux/nios2/libc.abilist
* sysdeps/unix/sysv/linux/powerpc/powerpc32/fpu/libc.abilist
* sysdeps/unix/sysv/linux/powerpc/powerpc32/nofpu/libc.abilist
* sysdeps/unix/sysv/linux/powerpc/powerpc64/libc-le.abilist
* sysdeps/unix/sysv/linux/powerpc/powerpc64/libc.abilist
* sysdeps/unix/sysv/linux/s390/s390-32/libc.abilist
* sysdeps/unix/sysv/linux/s390/s390-64/libc.abilist
* sysdeps/unix/sysv/linux/sh/libc.abilist
* sysdeps/unix/sysv/linux/sparc/sparc32/libc.abilist
* sysdeps/unix/sysv/linux/sparc/sparc64/libc.abilist
* sysdeps/unix/sysv/linux/tile/tilegx/tilegx32/libc.abilist
* sysdeps/unix/sysv/linux/tile/tilegx/tilegx64/libc.abilist
* sysdeps/unix/sysv/linux/tile/tilepro/libc.abilist
* sysdeps/unix/sysv/linux/x86_64/64/libc.abilist
* sysdeps/unix/sysv/linux/x86_64/x32/libc.abilist:
Add entries for explicit_bzero and __explicit_bzero_chk.
TS 18661-1 defines a macro FE_SNANS_ALWAYS_SIGNAL in <fenv.h>, to
indicate that the recommended practice regarding sNaNs (that
operations always produce a qNaN output with "invalid" exception, even
in the fmax / fmin / hypot / pow cases where a qNaN input would not
result in qNaN output) is followed.
Now that those functions with C99 special cases for NaNs have been
fixed not to apply those special cases to sNaN, only to qNaN, glibc
follows that recommended practice. This patch makes it define the
corresponding macro.
Since compiler optimizations may affect whether sNaNs behave as
expected and the macro relates to both language and library features,
it is only defined if __SUPPORT_SNAN__ is defined (which GCC defines
for -fsignaling-nans). It is also not defined if FE_INVALID is
undefined, since the recommended practice specifically refers to
raising the "invalid" exception, so it seems inappropriate to define
the macro for soft-float cases without support for exceptions.
(Further refinement would be possible in cases where bits/fenv.h is
shared by configurations both with and without exceptions support.)
Tested for x86_64 and x86, and also did compile-only testing for nios2
to cover the no-exceptions case.
* math/fenv.h
[__GLIBC_USE (IEC_60559_BFP_EXT) && FE_INVALID && __SUPPORT_SNAN__]
(FE_SNANS_ALWAYS_SIGNAL): New macro.
* math/test-fe-snans-always-signal.c: New file.
* math/Makefile (tests): Add test-fe-snans-always-signal.
(CFLAGS-test-fe-snans-always-signal.c): New variable.
* manual/arith.texi (Infinity and NaN): Document
FE_SNANS_ALWAYS_SIGNAL.
For many years, the only effect of these macros has been to make
unistd.h declare getlogin_r. _POSIX_C_SOURCE >= 199506L also causes
this function to be declared. However, people who don't carefully
read all the headers might be confused into thinking they need to
define _REENTRANT for any threaded code (as was indeed the case a long
time ago).
Therefore, remove __USE_REENTRANT, and make _REENTRANT and _THREAD_SAFE
into synonyms for _POSIX_C_SOURCE=199506L. This will only affect
programs that don't select a higher conformance level some other way.
For instance, -std=c89 -D_REENTRANT will see a change in visible
declarations, but -std=c99 -D_POSIX_C_SOURCE=200809L -D_REENTRANT won't,
and -D_REENTRANT all by itself also won't, because _DEFAULT_SOURCE
implies _POSIX_C_SOURCE > 199506.
* include/features.h: Remove __USE_REENTRANT. Treat _REENTRANT
and _THREAD_SAFE the same as _POSIX_C_SOURCE=199506L, if a higher
POSIX conformance level has not been selected by other macros.
* NEWS, manual/creature.texi: Document this change.
* posix/unistd.h, posix/bits/unistd.h: Don't check __USE_REENTRANT.
* include/libc-symbols.h: Don't define _REENTRANT.
* scripts/check-installed-headers.sh: Don't undefine _REENTRANT.
