When adding some of the TS 18661 narrowing functions for glibc 2.28, I
deferred adding corresponding <tgmath.h> support because of unresolved
questions about the specification for those type-generic macros,
especially in relation to _FloatN and _FloatNx types.
Those issues are now clarified in the response to Clarification
Request 13 to TS 18661-3, and this patch adds the deferred tgmath.h
support. As with other tgmath.h macros, there are fairly
straightforward implementations based on __builtin_tgmath for GCC 8
and later, which result in exactly the right function being called in
each case, and more complicated implementations for GCC 7 and earlier,
which generally result in a function being called whose arguments have
the right format (i.e. an alias for the right function), but which
might not be exactly the function name specified by TS 18661.
In one case with older compilers (f32x* macros, where the type
_Float64x exists and all the arguments have type _Float32 or
_Float32x), there is a further relaxation and the function called may
have arguments narrower than the one specified by the TS, but still
wide enough to represent the arguments exactly, so the result of the
call is unchanged (as this does not affect any case where rounding of
integer arguments might be involved). With GCC 6 or before this is
inherently unavoidable (but still harmless and not detectable by how
the compiled program behaves, unless it redefines the functions in
question like the testcases do) because _Float32x and _Float64 are
both typedefs for double in that case but the specified semantics
result in different functions, with different argument formats, being
called for those two argument types.
Tests for the new macros are handled through gen-tgmath-tests.py,
which deals with the special-case handling for older GCC.
Tested as follows: with the full glibc testsuite on x86_64 and x86
(with GCC 6, 7 and 8); with the math/ tests on aarch64 and arm (with
GCC 6, 7 and 8); with build-many-glibcs.py (with GCC 6, 7 and 9).
* math/tgmath.h [__HAVE_FLOAT128X]: Give error.
[(__HAVE_FLOAT64X && !__HAVE_FLOAT128)
|| (__HAVE_FLOAT128 && !__HAVE_FLOAT64X)]: Likewise.
(__TGMATH_2_NARROW_F): Likewise.
(__TGMATH_2_NARROW_D): New macro.
(__TGMATH_2_NARROW_F16): Likewise.
(__TGMATH_2_NARROW_F32): Likewise.
(__TGMATH_2_NARROW_F64): Likewise.
(__TGMATH_2_NARROW_F32X): Likewise.
(__TGMATH_2_NARROW_F64X): Likewise.
[__HAVE_BUILTIN_TGMATH] (__TGMATH_NARROW_FUNCS_F): Likewise.
[__HAVE_BUILTIN_TGMATH] (__TGMATH_NARROW_FUNCS_F16): Likewise.
[__HAVE_BUILTIN_TGMATH] (__TGMATH_NARROW_FUNCS_F32): Likewise.
[__HAVE_BUILTIN_TGMATH] (__TGMATH_NARROW_FUNCS_F64): Likewise.
[__HAVE_BUILTIN_TGMATH] (__TGMATH_NARROW_FUNCS_F32X): Likewise.
[__GLIBC_USE (IEC_60559_BFP_EXT_C2X)] (fadd): Likewise.
[__GLIBC_USE (IEC_60559_BFP_EXT_C2X)] (dadd): Likewise.
[__GLIBC_USE (IEC_60559_BFP_EXT_C2X)] (fdiv): Likewise.
[__GLIBC_USE (IEC_60559_BFP_EXT_C2X)] (ddiv): Likewise.
[__GLIBC_USE (IEC_60559_BFP_EXT_C2X)] (fmul): Likewise.
[__GLIBC_USE (IEC_60559_BFP_EXT_C2X)] (dmul): Likewise.
[__GLIBC_USE (IEC_60559_BFP_EXT_C2X)] (fsub): Likewise.
[__GLIBC_USE (IEC_60559_BFP_EXT_C2X)] (dsub): Likewise.
[__GLIBC_USE (IEC_60559_TYPES_EXT) && __HAVE_FLOAT16] (f16add):
Likewise.
[__GLIBC_USE (IEC_60559_TYPES_EXT) && __HAVE_FLOAT16] (f16div):
Likewise.
[__GLIBC_USE (IEC_60559_TYPES_EXT) && __HAVE_FLOAT16] (f16mul):
Likewise.
[__GLIBC_USE (IEC_60559_TYPES_EXT) && __HAVE_FLOAT16] (f16sub):
Likewise.
[__GLIBC_USE (IEC_60559_TYPES_EXT) && __HAVE_FLOAT32] (f32add):
Likewise.
[__GLIBC_USE (IEC_60559_TYPES_EXT) && __HAVE_FLOAT32] (f32div):
Likewise.
[__GLIBC_USE (IEC_60559_TYPES_EXT) && __HAVE_FLOAT32] (f32mul):
Likewise.
[__GLIBC_USE (IEC_60559_TYPES_EXT) && __HAVE_FLOAT32] (f32sub):
Likewise.
[__GLIBC_USE (IEC_60559_TYPES_EXT) && __HAVE_FLOAT64
&& (__HAVE_FLOAT64X || __HAVE_FLOAT128)] (f64add): Likewise.
[__GLIBC_USE (IEC_60559_TYPES_EXT) && __HAVE_FLOAT64
&& (__HAVE_FLOAT64X || __HAVE_FLOAT128)] (f64div): Likewise.
[__GLIBC_USE (IEC_60559_TYPES_EXT) && __HAVE_FLOAT64
&& (__HAVE_FLOAT64X || __HAVE_FLOAT128)] (f64mul): Likewise.
[__GLIBC_USE (IEC_60559_TYPES_EXT) && __HAVE_FLOAT64
&& (__HAVE_FLOAT64X || __HAVE_FLOAT128)] (f64sub): Likewise.
[__GLIBC_USE (IEC_60559_TYPES_EXT) && __HAVE_FLOAT32X] (f32xadd):
Likewise.
[__GLIBC_USE (IEC_60559_TYPES_EXT) && __HAVE_FLOAT32X] (f32xdiv):
Likewise.
[__GLIBC_USE (IEC_60559_TYPES_EXT) && __HAVE_FLOAT32X] (f32xmul):
Likewise.
[__GLIBC_USE (IEC_60559_TYPES_EXT) && __HAVE_FLOAT32X] (f32xsub):
Likewise.
[__GLIBC_USE (IEC_60559_TYPES_EXT) && __HAVE_FLOAT64X
&& (__HAVE_FLOAT128X || __HAVE_FLOAT128)] (f64xadd): Likewise.
[__GLIBC_USE (IEC_60559_TYPES_EXT) && __HAVE_FLOAT64X
&& (__HAVE_FLOAT128X || __HAVE_FLOAT128)] (f64xdiv): Likewise.
[__GLIBC_USE (IEC_60559_TYPES_EXT) && __HAVE_FLOAT64X
&& (__HAVE_FLOAT128X || __HAVE_FLOAT128)] (f64xmul): Likewise.
[__GLIBC_USE (IEC_60559_TYPES_EXT) && __HAVE_FLOAT64X
&& (__HAVE_FLOAT128X || __HAVE_FLOAT128)] (f64xsub): Likewise.
* math/gen-tgmath-tests.py (Type): Add members
non_standard_real_argument_types_list, long_double_type,
complex_float64_type and float32x_ext_type.
(Type.__init__): Set the new members.
(Type.floating_type): Add new argument floatn.
(Type.real_floating_type): Likewise.
(Type.can_combine_types): Likewise.
(Type.combine_types): Likewise.
(Type.init_types): Create internal Float32x_ext type.
(Tests.__init__): Define Float32x_ext in generated C code.
(Tests.add_tests): Handle narrowing functions.
(Tests.add_all_tests): Likewise.
(Tests.tests_text): Allow variation in mant_dig for narrowing
functions with compilers before GCC 8.
* math/Makefile (tgmath3-narrow-types): New variable.
(tgmath3-narrow-macros): Likewise.
(tgmath3-macros): Add $(tgmath3-narrow-macros).
The resolution of C floating-point Clarification Request 25
<http://www.open-std.org/jtc1/sc22/wg14/www/docs/n2397.htm#dr_25> is
that the totalorder and totalordermag functions should take pointer
arguments, and this has been adopted in C2X (with const added; note
that the integration of this change into C2X is present in the C
standard git repository but postdates the most recent public PDF
draft).
This patch updates glibc accordingly. As a defect resolution, the API
is changed unconditionally rather than supporting any sort of TS
18661-1 mode for compilation with the old version of the API. There
are compat symbols for existing binaries that pass floating-point
arguments directly. As a consequence of changing to pointer
arguments, there are no longer type-generic macros in tgmath.h for
these functions.
Because of the fairly complicated logic for creating libm function
aliases and determining the set of aliases to create in a given glibc
configuration, rather than duplicating all that in individual source
files to create the versioned and compat symbols, the source files for
the various versions of totalorder functions are set up to redefine
weak_alias before using libm_alias_* macros to create the symbols
required. In turn, this requires creating a separate alias for each
symbol version pointing to the same implementation (see binutils bug
<https://sourceware.org/bugzilla/show_bug.cgi?id=23840>), which is
done automatically using __COUNTER__. (As I noted in
<https://sourceware.org/ml/libc-alpha/2018-10/msg00631.html>, it might
well make sense for glibc's symbol versioning macros to do that alias
creation with __COUNTER__ themselves, which would somewhat simplify
the logic in the totalorder source files.)
It is of course desirable to test the compat symbols. I did this with
the generic libm-test machinery, but didn't wish to duplicate the
actual tables of test inputs and outputs, and thought it risky to
attempt to have a single object file refer to both default and compat
versions of the same function in order to test them together. Thus, I
created libm-test-compat_totalorder.inc and
libm-test-compat_totalordermag.inc which include the generated .c
files (with the processed version of those tables of inputs) from the
non-compat tests, and added appropriate dependencies. I think this
provides sufficient test coverage for the compat symbols without also
needing to make the special ldbl-96 and ldbl-128ibm tests (of
peculiarities relating to the representations of those formats that
can't be covered in the generic tests) run for the compat symbols.
Tests of compat symbols need to be internal tests, meaning _ISOMAC is
not defined. Making some libm-test tests into internal tests showed
up two other issues. GCC diagnoses duplicate macro definitions of
__STDC_* macros, including __STDC_WANT_IEC_60559_TYPES_EXT__; I added
an appropriate conditional and filed
<https://gcc.gnu.org/bugzilla/show_bug.cgi?id=91451> for this issue.
On ia64, include/setjmp.h ends up getting included indirectly from
libm-symbols.h, resulting in conflicting definitions of the STR macro
(also defined in libm-test-driver.c); I renamed the macros in
include/setjmp.h. (It's arguable that we should have common internal
headers used everywhere for stringizing and concatenation macros.)
Tested for x86_64 and x86, and with build-many-glibcs.py.
* math/bits/mathcalls.h
[__GLIBC_USE (IEC_60559_BFP_EXT) || __MATH_DECLARING_FLOATN]
(totalorder): Take pointer arguments.
[__GLIBC_USE (IEC_60559_BFP_EXT) || __MATH_DECLARING_FLOATN]
(totalordermag): Likewise.
* manual/arith.texi (totalorder): Likewise.
(totalorderf): Likewise.
(totalorderl): Likewise.
(totalorderfN): Likewise.
(totalorderfNx): Likewise.
(totalordermag): Likewise.
(totalordermagf): Likewise.
(totalordermagl): Likewise.
(totalordermagfN): Likewise.
(totalordermagfNx): Likewise.
* math/tgmath.h (__TGMATH_BINARY_REAL_RET_ONLY): Remove macro.
[__GLIBC_USE (IEC_60559_BFP_EXT)] (totalorder): Likewise.
[__GLIBC_USE (IEC_60559_BFP_EXT)] (totalordermag): Likewise.
* math/Versions (GLIBC_2.31): Add totalorder, totalorderf,
totalorderl, totalordermag, totalordermagf, totalordermagl,
totalorderf32, totalorderf64, totalorderf32x, totalordermagf32,
totalordermagf64, totalordermagf32x, totalorderf64x,
totalordermagf64x, totalorderf128 and totalordermagf128.
* math/Makefile (libm-test-funcs-noauto): Add compat_totalorder
and compat_totalordermag.
(libm-test-funcs-compat): New variable.
(libm-tests-compat): Likewise.
(tests): Do not include compat tests.
(tests-internal): Add compat tests.
($(foreach t,$(libm-tests-base),
$(objpfx)$(t)-compat_totalorder.o)): Depend
on $(objpfx)libm-test-totalorder.c.
($(foreach t,$(libm-tests-base),
$(objpfx)$(t)-compat_totalordermag.o): Depend on
$(objpfx)libm-test-totalordermag.c.
(tgmath3-macros): Remove totalorder and totalordermag.
* math/libm-test-compat_totalorder.inc: New file.
* math/libm-test-compat_totalordermag.inc: Likewise.
* math/libm-test-driver.c (struct test_ff_i_data): Update comment.
(RUN_TEST_fpfp_b): New macro.
(RUN_TEST_LOOP_fpfp_b): Likewise.
* math/libm-test-totalorder.inc (totalorder_test_data): Use
TEST_fpfp_b.
(totalorder_test): Condition on [!COMPAT_TEST].
(do_test): Likewise.
* math/libm-test-totalordermag.inc (totalordermag_test_data): Use
TEST_fpfp_b.
(totalordermag_test): Condition on [!COMPAT_TEST].
(do_test): Likewise.
* math/gen-tgmath-tests.py (Tests.add_all_tests): Remove
totalorder and totalordermag.
* math/test-tgmath.c (NCALLS): Change to 132.
(F(compile_test)): Do not call totalorder or totalordermag.
(F(totalorder)): Remove.
(F(totalordermag)): Likewise.
* include/float.h (__STDC_WANT_IEC_60559_TYPES_EXT__): Do not
define if [__STDC_WANT_IEC_60559_TYPES_EXT__].
* include/setjmp.h [!_ISOMAC] (STR_HELPER): Rename to
SJSTR_HELPER.
[!_ISOMAC] (STR): Rename to SJSTR. Update call to STR_HELPER.
[!_ISOMAC] (TEST_SIZE): Update call to STR.
[!_ISOMAC] (TEST_ALIGN): Likewise.
[!_ISOMAC] (TEST_OFFSET): Likewise.
* sysdeps/ieee754/dbl-64/s_totalorder.c: Include <shlib-compat.h>
and <first-versions.h>.
(__totalorder): Take pointer arguments. Add symbol versions and
compat symbols.
* sysdeps/ieee754/dbl-64/s_totalordermag.c: Include
<shlib-compat.h> and <first-versions.h>.
(__totalordermag): Take pointer arguments. Add symbol versions
and compat symbols.
* sysdeps/ieee754/dbl-64/wordsize-64/s_totalorder.c: Include
<shlib-compat.h> and <first-versions.h>.
(__totalorder): Take pointer arguments. Add symbol versions and
compat symbols.
* sysdeps/ieee754/dbl-64/wordsize-64/s_totalordermag.c: Include
<shlib-compat.h> and <first-versions.h>.
(__totalordermag): Take pointer arguments. Add symbol versions
and compat symbols.
* sysdeps/ieee754/float128/float128_private.h
(__totalorder_compatl): New macro.
(__totalordermag_compatl): Likewise.
* sysdeps/ieee754/flt-32/s_totalorderf.c: Include <shlib-compat.h>
and <first-versions.h>.
(__totalorderf): Take pointer arguments. Add symbol versions and
compat symbols.
* sysdeps/ieee754/flt-32/s_totalordermagf.c: Include
<shlib-compat.h> and <first-versions.h>.
(__totalordermagf): Take pointer arguments. Add symbol versions
and compat symbols.
* sysdeps/ieee754/ldbl-128/s_totalorderl.c: Include
<shlib-compat.h> and <first-versions.h>.
(__totalorderl): Take pointer arguments. Add symbol versions and
compat symbols.
* sysdeps/ieee754/ldbl-128/s_totalordermagl.c: Include
<shlib-compat.h> and <first-versions.h>.
(__totalordermagl): Take pointer arguments. Add symbol versions
and compat symbols.
* sysdeps/ieee754/ldbl-128ibm/s_totalorderl.c: Include
<shlib-compat.h>.
(__totalorderl): Take pointer arguments. Add symbol versions and
compat symbols.
* sysdeps/ieee754/ldbl-128ibm/s_totalordermagl.c: Include
<shlib-compat.h>.
(__totalordermagl): Take pointer arguments. Add symbol versions
and compat symbols.
* sysdeps/ieee754/ldbl-96/s_totalorderl.c: Include
<shlib-compat.h> and <first-versions.h>.
(__totalorderl): Take pointer arguments. Add symbol versions and
compat symbols.
* sysdeps/ieee754/ldbl-96/s_totalordermagl.c: Include
<shlib-compat.h> and <first-versions.h>.
(__totalordermagl): Take pointer arguments. Add symbol versions
and compat symbols.
* sysdeps/ieee754/ldbl-opt/nldbl-totalorder.c (totalorderl): Take
pointer arguments.
* sysdeps/ieee754/ldbl-opt/nldbl-totalordermag.c (totalordermagl):
Likewise.
* sysdeps/ieee754/ldbl-128ibm/test-totalorderl-ldbl-128ibm.c
(do_test): Update calls to totalorderl and totalordermagl.
* sysdeps/ieee754/ldbl-96/test-totalorderl-ldbl-96.c (do_test):
Update calls to totalorderl and totalordermagl.
* sysdeps/mach/hurd/i386/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/csky/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/be/libm.abilist:
Likewise.
* sysdeps/unix/sysv/linux/powerpc/powerpc64/le/libm.abilist:
Likewise.
* sysdeps/unix/sysv/linux/riscv/rv64/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/x86_64/64/libm.abilist: Likewise.
* sysdeps/unix/sysv/linux/x86_64/x32/libm.abilist: Likewise.
This patch starts preparation for C2X support in glibc headers by
adding a feature test macro _ISOC2X_SOURCE and corresponding
__GLIBC_USE (ISOC2X). (I chose to use the newer __GLIBC_USE style for
this rather than the older __USE_* macros tested with #ifdef.) As
with other such macros, C2X features are also enabled by compiling for
a standard newer than C17, or by using _GNU_SOURCE.
This patch does not itself enable anything new in the headers for C2X;
that is to be done in followup patches. (For example, most of the TS
18661-1 functions should be declared for C2X without any
__STDC_WANT_IEC_60559_BFP_EXT__ being needed, but the ones that
18661-1 adds to Annex F because of their close relation to IEEE 754
formats do still need the WANT macro in C2X.)
Once C2X becomes an actual standard we'll presumably move to using the
actual year in the feature test macro and __GLIBC_USE, with some
period when both macro spellings are accepted, as was done with
_ISOC9X_SOURCE.
Tested for x86_64.
* include/features.h (_ISOC2X_SOURCE): New feature test macro.
Undefine and define to 1 if [_GNU_SOURCE].
(__GLIBC_USE_ISOC2X): New macro. Undefine and redefine depending
on [_ISOC2X_SOURCE] and [__STDC_VERSION__ > 201710L].
(__USE_ISOC11): Also define to 1 if [_ISOC2X_SOURCE].
(__USE_ISOC99): Likewise.
(__USE_ISOC95): Likewise.
* manual/creature.texi (_ISOC2X_SOURCE): Document.
The new IFUNC resolver call ABI was introduced in
commit 2b8a3c86e7
Commit: Szabolcs Nagy <szabolcs.nagy@arm.com>
CommitDate: 2019-07-04 11:13:32 +0100
aarch64: new ifunc resolver ABI
See the commit log and the comments in sys/ifunc.h for details.
This change should be fully backwards-compatible because the old
code aborted the load if a soname mismatch was encountered
(instead of searching further for a matching symbol). This means
that no different symbols are found.
The soname check was explicitly disabled for the skip_map != NULL
case. However, this only happens with dl(v)sym and RTLD_NEXT,
and those lookups do not come with a verneed entry that could be used
for the check.
The error check was already explicitly disabled for the skip_map !=
NULL case, that is, when dl(v)sym was called with RTLD_NEXT. But
_dl_vsym always sets filename in the struct r_found_version argument
to NULL, so the check was not active anyway. This means that
symbol lookup results for the skip_map != NULL case do not change,
either.
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>
Now that there are no internal users of __sysctl left, it is possible
to add an unconditional deprecation warning to <sys/sysctl.h>.
To avoid a test failure due this warning in check-install-headers,
skip the test for sys/sysctl.h.
Reviewed-by: Adhemerval Zanella <adhemerval.zanella@linaro.org>
No 32-bit system call wrapper is added because the interface
is problematic because it cannot deal with 64-bit inode numbers
and 64-bit directory hashes.
A future commit will deprecate the undocumented getdirentries
and getdirentries64 functions.
Reviewed-by: Carlos O'Donell <carlos@redhat.com>
Linux only supports the required ISA sysctls on StrongARM devices,
which are armv4 and no longer tested during glibc development
and probably bit-rotted by this point. (No reported test results,
and the last discussion of armv4 support was in the glibc 2.19
release notes.)
GCC 9 dropped support for the SPE extensions to PowerPC, which means
powerpc*-*-*gnuspe* configurations are no longer buildable with that
compiler. This ISA extension was peculiar to the “e500” line of
embedded PowerPC chips, which, as far as I can tell, are no longer
being manufactured, so I think we should follow suit.
This patch was developed by grepping for “e500”, “__SPE__”, and
“__NO_FPRS__”, and may not eliminate every vestige of SPE support.
Most uses of __NO_FPRS__ are left alone, as they are relevant to
normal embedded PowerPC with soft-float.
* sysdeps/powerpc/preconfigure: Error out on powerpc-*-*gnuspe*
host type.
* scripts/build-many-glibcs.py: Remove powerpc-*-linux-gnuspe
and powerpc-*-linux-gnuspe-e500v1 from list of build configurations.
* sysdeps/powerpc/powerpc32/e500: Recursively delete.
* sysdeps/unix/sysv/linux/powerpc/powerpc32/e500: Recursively delete.
* sysdeps/unix/sysv/linux/powerpc/powerpc32/nofpu/context-e500.h:
Delete.
* sysdeps/powerpc/fpu_control.h: Remove SPE variant.
Issue an #error if used with a compiler in SPE-float mode.
* sysdeps/powerpc/powerpc32/__longjmp_common.S
* sysdeps/powerpc/powerpc32/setjmp_common.S
* sysdeps/unix/sysv/linux/powerpc/powerpc32/getcontext-common.S
* sysdeps/unix/sysv/linux/powerpc/powerpc32/nofpu/getcontext.S
* sysdeps/unix/sysv/linux/powerpc/powerpc32/nofpu/setcontext.S
* sysdeps/unix/sysv/linux/powerpc/powerpc32/nofpu/swapcontext.S
* sysdeps/unix/sysv/linux/powerpc/powerpc32/setcontext-common.S
* sysdeps/unix/sysv/linux/powerpc/powerpc32/swapcontext-common.S:
Remove code to preserve SPE register state.
* sysdeps/unix/sysv/linux/powerpc/elision-lock.c
* sysdeps/unix/sysv/linux/powerpc/elision-trylock.c
* sysdeps/unix/sysv/linux/powerpc/elision-unlock.c
Remove __SPE__ ifndefs.
The tgkill function is sometimes used in crash handlers.
<bits/signal_ext.h> follows the same approach as <bits/unistd_ext.h>
(which was added for the gettid system call wrapper).
Reviewed-by: Carlos O'Donell <carlos@redhat.com>
Unicode 12.1.0 Support: Character encoding, character type info, and
transliteration tables are all updated to Unicode 12.1.0, using
the generator scripts contributed by Mike FABIAN (Red Hat).
Some info about the number of characters added or changed:
Total added characters in newly generated CHARMAP: 1
added: <U32FF> /xe3/x8b/xbf SQUARE ERA NAME REIWA
Total added characters in newly generated WIDTH: 1
added: <U32FF> 2 : eaw=W category=So bidi=L name=SQUARE ERA NAME REIWA
graph: Added 1 characters in new ctype which were not in old ctype
graph: Added: ㋿ U+32FF SQUARE ERA NAME REIWA
print: Added 1 characters in new ctype which were not in old ctype
print: Added: ㋿ U+32FF SQUARE ERA NAME REIWA
punct: Added 1 characters in new ctype which were not in old ctype
punct: Added: ㋿ U+32FF SQUARE ERA NAME REIWA
The twalk function is very difficult to use in a multi-threaded
program because there is no way to pass external state to the
iterator function.
Reviewed-by: Carlos O'Donell <carlos@redhat.com>
Reviewed-by: Adhemerval Zanella <adhemerval.zanella@linaro.org>
Commit 2d6ab5df3b ("Document and fix
--enable-bind-now [BZ #21015]") extended BIND_NOW to all installed
shared objects. This change also covers installed programs.
Reviewed-by: Carlos O'Donell <carlos@redhat.com>
As discussed previously on libc-alpha [1], this patch follows up the idea
and add both the __attribute_alloc_size__ on malloc functions (malloc,
calloc, realloc, reallocarray, valloc, pvalloc, and memalign) and limit
maximum requested allocation size to up PTRDIFF_MAX (taking into
consideration internal padding and alignment).
This aligns glibc with gcc expected size defined by default warning
-Walloc-size-larger-than value which warns for allocation larger than
PTRDIFF_MAX. It also aligns with gcc expectation regarding libc and
expected size, such as described in PR#67999 [2] and previously discussed
ISO C11 issues [3] on libc-alpha.
From the RFC thread [4] and previous discussion, it seems that consensus
is only to limit such requested size for malloc functions, not the system
allocation one (mmap, sbrk, etc.).
The implementation changes checked_request2size to check for both overflow
and maximum object size up to PTRDIFF_MAX. No additional checks are done
on sysmalloc, so it can still issue mmap with values larger than
PTRDIFF_T depending on the requested size.
The __attribute_alloc_size__ is for functions that return a pointer only,
which means it cannot be applied to posix_memalign (see remarks in GCC
PR#87683 [5]). The runtimes checks to limit maximum requested allocation
size does applies to posix_memalign.
Checked on x86_64-linux-gnu and i686-linux-gnu.
[1] https://sourceware.org/ml/libc-alpha/2018-11/msg00223.html
[2] https://gcc.gnu.org/bugzilla//show_bug.cgi?id=67999
[3] https://sourceware.org/ml/libc-alpha/2011-12/msg00066.html
[4] https://sourceware.org/ml/libc-alpha/2018-11/msg00224.html
[5] https://gcc.gnu.org/bugzilla/show_bug.cgi?id=87683
[BZ #23741]
* malloc/hooks.c (malloc_check, realloc_check): Use
__builtin_add_overflow on overflow check and adapt to
checked_request2size change.
* malloc/malloc.c (__libc_malloc, __libc_realloc, _mid_memalign,
__libc_pvalloc, __libc_calloc, _int_memalign): Limit maximum
allocation size to PTRDIFF_MAX.
(REQUEST_OUT_OF_RANGE): Remove macro.
(checked_request2size): Change to inline function and limit maximum
requested size to PTRDIFF_MAX.
(__libc_malloc, __libc_realloc, _int_malloc, _int_memalign): Limit
maximum allocation size to PTRDIFF_MAX.
(_mid_memalign): Use _int_memalign call for overflow check.
(__libc_pvalloc): Use __builtin_add_overflow on overflow check.
(__libc_calloc): Use __builtin_mul_overflow for overflow check and
limit maximum requested size to PTRDIFF_MAX.
* malloc/malloc.h (malloc, calloc, realloc, reallocarray, memalign,
valloc, pvalloc): Add __attribute_alloc_size__.
* stdlib/stdlib.h (malloc, realloc, reallocarray, valloc): Likewise.
* malloc/tst-malloc-too-large.c (do_test): Add check for allocation
larger than PTRDIFF_MAX.
* malloc/tst-memalign.c (do_test): Disable -Walloc-size-larger-than=
around tests of malloc with negative sizes.
* malloc/tst-posix_memalign.c (do_test): Likewise.
* malloc/tst-pvalloc.c (do_test): Likewise.
* malloc/tst-valloc.c (do_test): Likewise.
* malloc/tst-reallocarray.c (do_test): Replace call to reallocarray
with resulting size allocation larger than PTRDIFF_MAX with
reallocarray_nowarn.
(reallocarray_nowarn): New function.
* NEWS: Mention the malloc function semantic change.
This functionality was deprecated in glibc 2.25.
This commit only includes the core changes to remove the
functionality. It does not remove the RES_USE_INET6 handling in the
individual NSS service modules and the res_use_inet6 function.
These changes will happen in future commits.
The Japanese era name will be changed on May 1, 2019. The Japanese
government made a preliminary announcement on April 1, 2019.
The glibc ja_JP locale must be updated to include the new era name for
strftime's alternative year format support.
Checked on x86_64-linux-gnu.
Reviewed-by: Carlos O'Donell <carlos@redhat.com>
ChangeLog:
[BZ #22964]
* localedata/locales/ja_JP (LC_TIME): Add entry for the new Japanese
era.
* time/tst-strftime2.c (dates): Add 2019-04-30 and 2019-05-01.
(mkreftable): Add rules for the new Japanese era and the new dates.
The stub implementations are turned into compat symbols.
Linux actually has two reserved system call numbers (for getpmsg
and putpmsg), but these system calls have never been implemented,
and there are no plans to implement them, so this patch replaces
the wrappers with the generic stubs.
According to <https://bugzilla.redhat.com/show_bug.cgi?id=436349>,
the presence of the XSI STREAMS declarations is a minor portability
hazard because they are not actually implemented.
This commit does not change the TIRPC support code in
sunrpc/rpc_svcout.c. It uses additional XTI functionality and
therefore never worked with glibc.
Reviewed-by: Carlos O'Donell <carlos@redhat.com>
Unicode 12.0.0 Support: Character encoding, character type info, and
transliteration tables are all updated to Unicode 12.0.0, using
the generator scripts contributed by Mike FABIAN (Red Hat).
Some info about the number of characters added or changed:
Total added characters in newly generated CHARMAP: 554
Total added characters in newly generated WIDTH: 106
alpha: Missing 8 characters of old ctype in new ctype
(These are combining marks, apparently they were removed from alpha
on purpose)
alpha: Added 295 characters in new ctype which were not in old ctype
combining: Missing 2 characters of old ctype in new ctype
(U+1CF2 VEDIC SIGN ARDHAVISARGA and U+1CF3 VEDIC SIGN ROTATED ARDHAVISARGA,
these are now "Alphabetic" in Unicode 12.0.0)
combining: Added 37 characters in new ctype which were not in old ctype
combining_level3: Missing 2 characters of old ctype in new ctype
(U+1CF2 VEDIC SIGN ARDHAVISARGA and U+1CF3 VEDIC SIGN ROTATED ARDHAVISARGA,
these are now "Alphabetic" in Unicode 12.0.0)
combining_level3: Added 26 characters in new ctype which were not in old ctype
graph: Added 554 characters in new ctype which were not in old ctype
lower: Added 6 characters in new ctype which were not in old ctype
print: Added 554 characters in new ctype which were not in old ctype
punct: Missing 29 characters of old ctype in new ctype
(These characters have all become "Alphabetic" in Unicode 12.0.0.
Therefore, they are not in "punct" anymore (see: is_punct() in unicode_utils.py))
punct: Added 296 characters in new ctype which were not in old ctype
tolower: Added 7 characters in new ctype which were not in old ctype
totitle: Added 7 characters in new ctype which were not in old ctype
toupper: Added 7 characters in new ctype which were not in old ctype
upper: Added 7 characters in new ctype which were not in old ctype
[BZ #24307]
* localedata/unicode-gen/Makefile (UNICODE_VERSION): Set to 12.0.0.
* localedata/unicode-gen/DerivedCoreProperties.txt: Update to Unicode 12.0.0.
* localedata/unicode-gen/EastAsianWidth.txt: Likewise.
* localedata/unicode-gen/PropList.txt: Likewise.
* localedata/unicode-gen/UnicodeData.txt: Likewise.
* localedata/unicode-gen/ctype_compatibility_test_cases.py: U+108D became
"Alphabetic" in Unicode 12.0.0. Adapt test case.
* localedata/charmaps/UTF-8: Regenerate.
* localedata/locales/i18n_ctype: Likewise.
* localedata/locales/tr_TR: Likewise.
* localedata/locales/translit_circle: Likewise.
* localedata/locales/translit_cjk_compat: Likewise.
* localedata/locales/translit_combining: Likewise.
* localedata/locales/translit_compat: Likewise.
* localedata/locales/translit_font: Likewise.
* localedata/locales/translit_fraction: Likewise.
This commit adds gettid to <unistd.h> on Linux, and not to the
kernel-independent GNU API.
gettid is now supportable on Linux because too many things assume a
1:1 mapping between libpthread threads and kernel threads.
Reviewed-by: Carlos O'Donell <carlos@redhat.com>
As the result of commit 6e6249d0b4
("BZ#14743: Move clock_* symbols from librt to libc."), in glibc 2.17,
clock_gettime, clock_getres, clock_settime, clock_getcpuclockid,
clock_nanosleep were added to libc, and the file rt/clock-compat.c
was added with forwarders to the actual implementations in libc.
These forwarders were wrapped in
#if SHLIB_COMPAT (librt, GLIBC_2_2, GLIBC_2_17)
so that they are not present for newer architectures (such as
powerpc64le) with a 2.17 or later ABI baseline. But the forwarders
were not marked as compatibility symbols. As a result, on older
architectures, historic configure checks such as
AC_CHECK_LIB(rt, clock_gettime)
still cause linking against librt, even though this is completely
unnecessary. It also creates a needless porting hazard because
architectures behave differently when it comes to symbol availability.
Reviewed-by: Carlos O'Donell <carlos@redhat.com>
Since the size argument is unsigned. we should use unsigned Jcc
instructions, instead of signed, to check size.
Tested on x86-64 and x32, with and without --disable-multi-arch.
[BZ #24155]
CVE-2019-7309
* NEWS: Updated for CVE-2019-7309.
* sysdeps/x86_64/memcmp.S: Use RDX_LP for size. Clear the
upper 32 bits of RDX register for x32. Use unsigned Jcc
instructions, instead of signed.
* sysdeps/x86_64/x32/Makefile (tests): Add tst-size_t-memcmp-2.
* sysdeps/x86_64/x32/tst-size_t-memcmp-2.c: New test.
As discussed during development for glibc 2.29, when we increased the
required minimum GCC version for building glibc to GCC 5, working
purely based on the times at which such requirements have been
increased in the past it would be appropriate for glibc 2.30 to
require GCC 6 (matching GCC 4.9 having been required for glibc 2.26).
Naming 6.2 specifically as the minimum version then means a separate
version requirement no longer needs to be specified for powerpc64le.
Thus, this patch increases the minimum to 6.2, removing the
documentation of the separate requirement for powerpc64le. It does
not remove the powerpc64le configure test, or any __GNUC_PREREQ that
could be removed as not being in installed headers or files shared
with gnulib; I think such cleanups are best done separately.
Tested for x86_64.
* configure.ac (libc_cv_compiler_ok): Require GCC 6.2 or later.
* configure: Regenerated.
* manual/install.texi (Tools for Compilation): Update minimum GCC
version.
* INSTALL: Regenerated.
* NEWS: Add the list of bugs fixed in 2.29.
* manual/contrib.texi: Update contributors list with some more
names.
* manual/install.texi: Update latest versions of packages
tested.
* INSTALL: Regenerated.
The full representation of the alternative calendar year (%EY)
typically includes an internal use of "%Ey". As a GNU extension,
apply any flags on "%EY" (e.g. "%_EY", "%-EY") to the internal "%Ey",
allowing users of "%EY" to control how the year is padded.
Reviewed-by: Rafal Luzynski <digitalfreak@lingonborough.com>
Reviewed-by: Zack Weinberg <zackw@panix.com>
ChangeLog:
[BZ #24096]
* manual/time.texi (strftime): Document "%EC" and "%EY".
* time/Makefile (tests): Add tst-strftime2.
(LOCALES): Add ja_JP.UTF-8, lo_LA.UTF-8, and th_TH.UTF-8.
* time/strftime_l.c (__strftime_internal): Add argument yr_spec to
override padding for "%Ey".
If an optional flag ('_' or '-') is specified to "%EY", interpret the
"%Ey" in the subformat as if decorated with that flag.
* time/tst-strftime2.c: New file.
In Japanese locales, strftime's alternative year format (%Ey) produces
a year numbered within a time period called an _era_. A new era
typically begins when a new emperor is enthroned. The result of "%Ey"
is therefore usually a one- or two-digit number.
Many programs that display Japanese era dates assume that the era year
is two digits wide. To improve how these programs display dates
during the first nine years of a new era, change "%Ey" to pad one-
digit numbers on the left with a zero. This change applies to all
locales. It is expected to be harmless for other locales that use the
alternative year format (e.g. lo_LA and th_TH, in which "%Ey" produces
the year of the Buddhist calendar) as those calendars' year numbers
are already more than two digits wide, and this is not expected to
change.
This change needs to be in place before 2019-05-01 CE, as a new era is
scheduled to begin on that date.
Reviewed-by: Zack Weinberg <zackw@panix.com>
Reviewed-by: Rafal Luzynski <digitalfreak@lingonborough.com>
ChangeLog:
[BZ #23758]
* manual/time.texi (strftime): Document "%Ey".
* time/strftime_l.c (__strftime_internal): Set the default width
padding with zero of "%Ey" to 2.
The IPv4 address parser in the getaddrinfo function is changed so that
it does not ignore trailing whitespace and all characters after it.
For backwards compatibility, the getaddrinfo function still recognizes
legacy name syntax, such as 192.000.002.010 interpreted as 192.0.2.8
(octal).
This commit does not change the behavior of inet_addr and inet_aton.
gethostbyname already had additional sanity checks (but is switched
over to the new __inet_aton_exact function for completeness as well).
To avoid sending the problematic query names over DNS, commit
6ca53a2453 ("resolv: Do not send queries
for non-host-names in nss_dns [BZ #24112]") is needed.
On x32, the size_t parameter may be passed in the lower 32 bits of a
64-bit register with the non-zero upper 32 bits. The string/memory
functions written in assembly can only use the lower 32 bits of a
64-bit register as length or must clear the upper 32 bits before using
the full 64-bit register for length.
This pach fixes memchr/wmemchr for x32. Tested on x86-64 and x32. On
x86-64, libc.so is the same with and withou the fix.
[BZ# 24097]
CVE-2019-6488
* sysdeps/x86_64/memchr.S: Use RDX_LP for length. Clear the
upper 32 bits of RDX register.
* sysdeps/x86_64/multiarch/memchr-avx2.S: Likewise.
* sysdeps/x86_64/x32/Makefile (tests): Add tst-size_t-memchr and
tst-size_t-wmemchr.
* sysdeps/x86_64/x32/test-size_t.h: New file.
* sysdeps/x86_64/x32/tst-size_t-memchr.c: Likewise.
* sysdeps/x86_64/x32/tst-size_t-wmemchr.c: Likewise.
The only difference between noncompliant and C99-compliant scanf is
that the former accepts the archaic GNU extension '%as' (also %aS and
%a[...]) meaning to allocate space for the input string with malloc.
This extension conflicts with C99's use of %a as a format _type_
meaning to read a floating-point number; POSIX.1-2008 standardized
equivalent functionality using the modifier letter 'm' instead (%ms,
%mS, %m[...]).
The extension was already disabled in most conformance modes:
specifically, any mode that doesn't involve _GNU_SOURCE and _does_
involve either strict conformance to C99 or loose conformance to both
C99 and POSIX.1-2001 would get the C99-compliant scanf. With
compilers new enough to use -std=gnu11 instead of -std=gnu89, or
equivalent, that includes the default mode.
With this patch, we now provide C99-compliant scanf in all
configurations except when _GNU_SOURCE is defined *and*
__STDC_VERSION__ or __cplusplus (whichever is relevant) indicates
C89/C++98. This leaves the old scanf available under e.g. -std=c89
-D_GNU_SOURCE, but removes it from e.g. -std=gnu11 -D_GNU_SOURCE (it
was already not present under -std=gnu11 without -D_GNU_SOURCE) and
from -std=gnu89 without -D_GNU_SOURCE.
There needs to be an internal override so we can compile the
noncompliant scanf itself. This is the same problem we had when we
removed 'gets' from _GNU_SOURCE and it's dealt with the same way:
there's a new __GLIBC_USE symbol, DEPRECATED_SCANF, which defaults to
off under the appropriate conditions for external code, but can be
overridden by individual files within stdio.
We also run into problems with PLT bypass for internal uses of sscanf,
because libc_hidden_proto uses __REDIRECT and so does the logic in
stdio.h for choosing which implementation of scanf to use; __REDIRECT
isn't transitive, so include/stdio.h needs to bridge the gap with a
macro. As far as I can tell, sscanf is the only function in this
family that's internally called by unrelated code.
Finally, there are several tests in stdio-common that use the
extension. bug21.c is a regression test for a crash; it still
exercises the relevant code when changed to use %ms instead of %as.
scanf14.c through scanf17.c are more complicated since they are
actually testing the subtleties of the extension - under what
circumstances is 'a' treated as a modifier letter, etc. I changed all
of them to use %ms instead of %as as well, but duplicated scanf14.c
and scanf16.c as scanf14a.c and scanf16a.c. These still use %as and
are compiled with -std=gnu89 to access the old extension. A bunch of
diagnostic overrides and manual workarounds for the old stdio.h
behavior become unnecessary. Yay!
* include/features.h (__GLIBC_USE_DEPRECATED_SCANF): New __GLIBC_USE
parameter. Only use deprecated scanf when __USE_GNU is defined
and __STDC_VERSION__ is less than 199901L or __cplusplus is less
than 201103L, whichever is relevant for the language being compiled.
* libio/stdio.h, libio/bits/stdio-ldbl.h: Decide whether to redirect
scanf, fscanf, sscanf, vscanf, vfscanf, and vsscanf to their
__isoc99_ variants based only on __GLIBC_USE (DEPRECATED_SCANF).
* wcsmbs/wchar.h: wcsmbs/bits/wchar-ldbl.h: Likewise for
wscanf, fwscanf, swscanf, vwscanf, vfwscanf, and vswscanf.
* libio/iovsscanf.c
* libio/fwscanf.c
* libio/iovswscanf.c
* libio/swscanf.c
* libio/vscanf.c
* libio/vwscanf.c
* libio/wscanf.c
* stdio-common/fscanf.c
* stdio-common/scanf.c
* stdio-common/vfscanf.c
* stdio-common/vfwscanf.c
* sysdeps/ieee754/ldbl-opt/nldbl-compat.c
* sysdeps/ieee754/ldbl-opt/nldbl-fscanf.c
* sysdeps/ieee754/ldbl-opt/nldbl-fwscanf.c
* sysdeps/ieee754/ldbl-opt/nldbl-iovfscanf.c
* sysdeps/ieee754/ldbl-opt/nldbl-scanf.c
* sysdeps/ieee754/ldbl-opt/nldbl-sscanf.c
* sysdeps/ieee754/ldbl-opt/nldbl-swscanf.c
* sysdeps/ieee754/ldbl-opt/nldbl-vfscanf.c
* sysdeps/ieee754/ldbl-opt/nldbl-vfwscanf.c
* sysdeps/ieee754/ldbl-opt/nldbl-vscanf.c
* sysdeps/ieee754/ldbl-opt/nldbl-vsscanf.c
* sysdeps/ieee754/ldbl-opt/nldbl-vswscanf.c
* sysdeps/ieee754/ldbl-opt/nldbl-vwscanf.c
* sysdeps/ieee754/ldbl-opt/nldbl-wscanf.c:
Override __GLIBC_USE_DEPRECATED_SCANF to 1.
* stdio-common/sscanf.c: Likewise. Remove ldbl_hidden_def for __sscanf.
* stdio-common/isoc99_sscanf.c: Add libc_hidden_def for __isoc99_sscanf.
* include/stdio.h: Provide libc_hidden_proto for __isoc99_sscanf,
not sscanf.
[!__GLIBC_USE (DEPRECATED_SCANF)]: Define sscanf as __isoc99_scanf
with a preprocessor macro.
* stdio-common/bug21.c, stdio-common/scanf14.c:
Use %ms instead of %as, %mS instead of %aS, %m[] instead of %a[];
remove DIAG_IGNORE_NEEDS_COMMENT for -Wformat.
* stdio-common/scanf16.c: Likewise. Add __attribute__ ((format (scanf)))
to xscanf, xfscanf, xsscanf.
* stdio-common/scanf14a.c: New copy of scanf14.c which still uses
%as, %aS, %a[]. Remove DIAG_IGNORE_NEEDS_COMMENT for -Wformat.
* stdio-common/scanf16a.c: New copy of scanf16.c which still uses
%as, %aS, %a[]. Add __attribute__ ((format (scanf))) to xscanf,
xfscanf, xsscanf.
* stdio-common/scanf15.c, stdio-common/scanf17.c: No need to
override feature selection macros or provide definitions of u_char etc.
* stdio-common/Makefile (tests): Add scanf14a and scanf16a.
(CFLAGS-scanf15.c, CFLAGS-scanf17.c): Remove.
(CFLAGS-scanf14a.c, CFLAGS-scanf16a.c): New. Compile these files
with -std=gnu89.
We know that building glibc with GCC 4.9 is broken on various
platforms (bug 23993). As it's more than a year since we last
increased the minimum GCC version to build glibc, this patch changes
the requirement to be GCC 5 or later (indeed, based on 4.9 having been
required for building 2.26, it would be consistent in terms of timing
to require GCC 6 or later from the 2.30 release onwards). It
deliberately just updates the configure test and corresponding
documentation, leaving removal of no-longer-needed __GNUC_PREREQ tests
for a separate patch.
In the NEWS entry, the requirement for a newer GCC version for
powerpc64le is reiterated (as in the entry for the 4.9 requirement in
2.26) to avoid suggesting the version requirement there has gone down.
(If that version goes up further as part of support for binary128 long
double, of course the wording would change at that time.)
Tested for x86_64.
[BZ #23993]
* configure.ac (libc_cv_compiler_ok): Require GCC 5 or later.
* configure: Regenerated.
* manual/install.texi (Tools for Compilation): Update minimum GCC
version.
* INSTALL: Regenerated.
Along with posix_spawn_file_actions_addchdir,
posix_spawn_file_actions_addfchdir is the subject of a change proposal
for POSIX: <http://austingroupbugs.net/view.php?id=1208>
This patch uses posix_spawn on popen instead of fork and execl. On Linux
this has the advantage of much lower memory consumption (usually 32 Kb
minimum for the mmap stack area).
Two issues are also fixed with this change:
* BZ#17490: although POSIX pthread_atfork description only list 'fork'
as the function that should execute the atfork handlers, popen
description states that:
'[...] shall be *as if* a child process were created within the popen()
call using the fork() function [...]'
Other libc/system seems to follow the idea atfork handlers should not be
executed for popen:
libc/system | run atfork handles | notes
------------|----------------------|---------------------------------------
Freebsd | no | uses vfork
Solaris 11 | no |
MacOSX 11 | no | implemented through posix_spawn syscall
------------|----------------------|----------------------------------------
Similar to posix_spawn and system, popen idea is to spawn a different
binary so all the POSIX rationale to run the atfork handlers to avoid
internal process inconsistency is not really required and in some cases
might be unsafe.
* BZ#22834: the described scenario, where the forked process might access
invalid memory due an inconsistent state in multithreaded environment,
should not happen because posix_spawn does not access the affected
data structure (proc_file_chain).
Checked on x86_64-linux-gnu and i686-linux-gnu.
[BZ #22834]
[BZ #17490]
* NEWS: Add new semantic for atfork with popen and system.
* libio/iopopen.c (_IO_new_proc_open): use posix_spawn instead of
fork and execl.
