The lgamma (and likewise lgammaf, lgammal) function wrongly sets the
signgam variable even when building for strict ISO C conformance
(-std=c99 / -std=c11), although the user may define such a variable
and it's only in the implementation namespace for POSIX with XSI
extensions enabled.
Following discussions starting at
<https://sourceware.org/ml/libc-alpha/2013-04/msg00767.html> and
<https://sourceware.org/ml/libc-alpha/2015-10/msg00844.html>, it seems
that the safest approach for fixing this particular issue is for
signgam to become a weak alias for a newly exported symbol __signgam,
with the library functions only setting __signgam, at which point
static linker magic will preserve the alias for newly linked binaries
that refer to the library's signgam rather than defining their own,
while breaking the alias for programs that define their own signgam,
with new symbol versions for lgamma functions and with compat symbols
for existing binaries that set both signgam and __signgam.
This patch implements that approach for the fix. signgam is made into
a weak alias. The four symbols __signgam, lgamma, lgammaf, lgammal
get new symbol versions at version GLIBC_2.23, with the existing
versions of lgamma, lgammaf and lgammal becoming compat symbols.
When the compat versions are built, gamma, gammaf and gammal are
aliases for the compat versions (i.e. always set signgam); this is OK
as they are not ISO C functions, and avoids adding new symbol versions
for them unnecessarily. When the compat versions are not built
(i.e. for static linking and for future glibc ports), gamma, gammaf
and gammal are aliases for the new versions that set __signgam. The
ldbl-opt versions are updated accordingly.
The lgamma wrappers are adjusted so that the same source files,
included from different files with different definitions of
USE_AS_COMPAT, can build either the new versions or the compat
versions. Similar changes are made to the ia64 versions (untested).
Tests are added that the lgamma functions do not interfere with a user
variable called signgam for ISO C, with various choices for the size
of that variable, whether it is initialized, and for static and
dynamic linking. The conformtest whitelist entry is removed as well.
Tested for x86_64, x86, mips64 and powerpc, including looking at
objdump --dynamic-syms output to make sure the expected sets of
symbols were aliases. Also spot-tested that a binary built with old
glibc works properly (i.e. gets signgam set) when run with new glibc.
[BZ #15421]
* sysdeps/ieee754/s_signgam.c (signgam): Rename to __signgam,
initialize with 0 and define as weak alias of __signgam.
* include/math.h [!_ISOMAC] (__signgam): Declare.
* math/Makefile (libm-calls): Add w_lgamma_compat.
(tests): Add test-signgam-uchar, test-signgam-uchar-init,
test-signgam-uint, test-signgam-uint-init, test-signgam-ullong and
test-signgam-ullong-init.
(tests-static): Add test-signgam-uchar-static,
test-signgam-uchar-init-static, test-signgam-uint-static,
test-signgam-uint-init-static, test-signgam-ullong-static and
test-signgam-ullong-init-static.
(CFLAGS-test-signgam-uchar.c): New variable.
(CFLAGS-test-signgam-uchar-init.c): Likewise.
(CFLAGS-test-signgam-uchar-static.c): Likewise.
(CFLAGS-test-signgam-uchar-init-static.c): Likewise.
(CFLAGS-test-signgam-uint.c): Likewise.
(CFLAGS-test-signgam-uint-init.c): Likewise.
(CFLAGS-test-signgam-uint-static.c): Likewise.
(CFLAGS-test-signgam-uint-init-static.c): Likewise.
(CFLAGS-test-signgam-ullong.c): Likewise.
(CFLAGS-test-signgam-ullong-init.c): Likewise.
(CFLAGS-test-signgam-ullong-static.c): Likewise.
(CFLAGS-test-signgam-ullong-init-static.c): Likewise.
* math/Versions (libm): Add GLIBC_2.23.
* math/lgamma-compat.h: New file.
* math/test-signgam-main.c: Likewise.
* math/test-signgam-uchar-init-static.c: Likewise.
* math/test-signgam-uchar-init.c: Likewise.
* math/test-signgam-uchar-static.c: Likewise.
* math/test-signgam-uchar.c: Likewise.
* math/test-signgam-uint-init-static.c: Likewise.
* math/test-signgam-uint-init.c: Likewise.
* math/test-signgam-uint-static.c: Likewise.
* math/test-signgam-uint.c: Likewise.
* math/test-signgam-ullong-init-static.c: Likewise.
* math/test-signgam-ullong-init.c: Likewise.
* math/test-signgam-ullong-static.c: Likewise.
* math/test-signgam-ullong.c: Likewise.
* math/w_lgamma.c: Rename to w_lgamma_main.c and replace by
wrapper of w_lgamma_main.c.
* math/w_lgamma_compat.c: New file.
* math/w_lgamma_compatf.c: Likewise.
* math/w_lgamma_compatl.c: Likewise.
* math/w_lgamma_main.c: New file. Based on w_lgamma.c. Include
<lgamma-compat.h>. Condition contents on [BUILD_LGAMMA]. Support
defining compatibility symbols.
(__lgamma): Change to LGFUNC (__lgamma). Use CALL_LGAMMA.
* math/w_lgammaf.c: Rename to w_lgammaf_main.c and replace by
wrapper of w_lgammaf_main.c.
* math/w_lgammaf_main.c: New file. Based on w_lgammaf.c. Include
<lgamma-compat.h>. Condition contents on [BUILD_LGAMMA]. Support
defining compatibility symbols.
(__lgammaf): Change to LGFUNC (__lgammaf). Use CALL_LGAMMA.
* math/w_lgammal.c: Rename to w_lgammal_main.c and replace by
wrapper of w_lgammal_main.c.
* math/w_lgammal_main.c: New file. Based on w_lgammal.c. Include
<lgamma-compat.h>. Condition contents on [BUILD_LGAMMA]. Support
defining compatibility symbols.
(__lgammal): Change to LGFUNC (__lgammal). Use CALL_LGAMMA.
* sysdeps/ia64/fpu/lgamma-compat.h: New file.
* sysdeps/ia64/fpu/w_lgamma.c: Move to ....
* sysdeps/ia64/fpu/w_lgamma_main.c: ...here. Include
<lgamma-compat.h>.
(__ieee754_lgamma): Change to LGFUNC (lgamma). Use CALL_LGAMMA.
(__ieee754_gamma): Define as alias.
* sysdeps/ia64/fpu/w_lgammaf.c: Move to ....
* sysdeps/ia64/fpu/w_lgammaf_main.c: ...here. Include
<lgamma-compat.h>.
(__ieee754_lgammaf): Change to LGFUNC (lgammaf). Use CALL_LGAMMA.
(__ieee754_gammaf): Define as alias.
* sysdeps/ia64/fpu/w_lgammal.c: Move to ....
* sysdeps/ia64/fpu/w_lgammal_main.c: ...here. Include
<lgamma-compat.h>.
(__ieee754_lgammal): Change to LGFUNC (lgammal). Use CALL_LGAMMA.
(__ieee754_gammal): Define as alias.
* sysdeps/ieee754/ldbl-opt/w_lgamma.c: Move to ....
* sysdeps/ieee754/ldbl-opt/w_lgamma_compat.c: ...here. Include
<math/w_lgamma_compat.c>.
[LONG_DOUBLE_COMPAT(libm, GLIBC_2_0)] (__lgammal_dbl_compat):
Define as alias of __lgamma_compat and use in defining lgammal.
* sysdeps/ieee754/ldbl-opt/w_lgammal.c: Move to ....
* sysdeps/ieee754/ldbl-opt/w_lgamma_compatl.c: ...here. Include
<math/lgamma-compat.h> and <math/w_lgamma_compatl.c>.
(USE_AS_COMPAT): New macro.
(LGAMMA_OLD_VER): Undefine and redefine.
(lgammal): Do not define here.
(gammal): Only define here if [GAMMA_ALIAS].
* conform/linknamespace.pl (@whitelist): Remove signgam.
* 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.
The new format lists the version on each line, as in:
VERSION SYMBOL TYPE [VALUE]
This makes it easier to process the files with line-oriented tools.
The abilist files were converted with this awk script:
/^[^ ]/ { version = $1 }
/^ / { print version, substr($0, 2) }
And sorted under the "C" locale with sort.
This patch added a new fmemopen version, for glibc 2.22, that aims to be
POSIX complaint. It fixes some long-stading glibc fmemopen issues, such
as:
* it changes the way fseek with SEEK_END works on fmemopen to seek
relative to buffer size instead of first '\0'. This is default mode and
'b' opening mode does not change internal behavior (bz#6544).
* fix apending opening mode to use as start position either first null
byte of len specified in function call (bz#13152 and #13151).
* remove binary option 'b' and internal different handling (bz#12836)
* fix seek/SEE_END with negative values (bz#14292).
A compatibility symbol is provided to with old behavior for older symbols
version (2.2.5).
* include/stdio.h (fmemopen): Remove hidden prototype.
(__fmemopen): Add new hidden prototype.
* libio/Makefile: Add oldfmemopen object.
* libio/Versions [GLIBC_2.22]: Add new fmemopen symbol.
* libio/fmemopen.c (__fmemopen): Function rewrite to be POSIX
compliance.
* libio/oldfmemopen.c: New file: old fmemopen implementation for
symbol compatibility.
* stdio-common/Makefile [tests]: Add new tst-fmemopen3.
* stdio-common/psiginfo.c [psiginfo]: Call __fmemopen instead of
fmemopen.
* stdio-common/tst-fmemopen3.c: New file: more fmemopen tests, focus
on append and read mode.
* sysdeps/unix/sysv/linux/aarch64/libc.abilist [GLIBC_2.22]: Add
fmemopen.
* sysdeps/unix/sysv/linux/alpha/libc.abilist [GLIBC_2.22]: Likewise.
* sysdeps/unix/sysv/linux/arm/libc.abilist [GLIBC_2.22]: Likewise.
* sysdeps/unix/sysv/linux/i386/libc.abilist [GLIBC_2.22]: Likewise.
* sysdeps/unix/sysv/linux/ia64/libc.abilist [GLIBC_2.22]:
Likewise.
* sysdeps/unix/sysv/linux/m68k/coldfire/libc.abilist
[GLIBC_2.22]: Likewise.
* sysdeps/unix/sysv/linux/m68k/m680x0/libc.abilist [GLIBC_2.22]:
Likewise.
* sysdeps/unix/sysv/linux/microblaze/libc.abilist [GLIBC_2.22]:
Likewise.
* sysdeps/unix/sysv/linux/mips/mips32/fpu/libc.abilist
[GLIBC_2.22]: Likewise.
* sysdeps/unix/sysv/linux/mips/mips32/nofpu/libc.abilist
[GLIBC_2.22]: Likewise.
* sysdeps/unix/sysv/linux/mips/mips64/n32/libc.abilist
[GLIBC_2.22]: Likewise.
* sysdeps/unix/sysv/linux/mips/mips64/n64/libc.abilist
[GLIBC_2.22]: Likewise.
* sysdeps/unix/sysv/linux/powerpc/powerpc32/fpu/libc.abilist
[GLIBC_2.22]: Likewise.
* sysdeps/unix/sysv/linux/powerpc/powerpc32/nofpu/libc.abilist
[GLIBC_2.22]: Likewise.
* sysdeps/unix/sysv/linux/powerpc/powerpc64/libc.abilist
[GLIBC_2.22]: Likewise.
* sysdeps/unix/sysv/linux/s390/s390-32/libc.abilist [GLIBC_2.22]:
Likewise.
* sysdeps/unix/sysv/linux/s390/s390-64/libc.abilist [GLIBC_2.22]:
Likewise.
* sysdeps/unix/sysv/linux/sh/libc.abilist [GLIBC_2.22]: Likewise.
* sysdeps/unix/sysv/linux/sparc/sparc32/libc.abilist
[GLIBC_2.22]: Likewise.
* sysdeps/unix/sysv/linux/sparc/sparc64/libc.abilist
[GLIBC_2.22]: Likewise.
* sysdeps/unix/sysv/linux/tile/tilegx/tilegx32/libc.abilist
[GLIBC_2.22]: Likewise.
* sysdeps/unix/sysv/linux/tile/tilegx/tilegx64/libc.abilist
[GLIBC_2.22]: Likewise.
* sysdeps/unix/sysv/linux/tile/tilepro/libc.abilist [GLIBC_2.22]:
Likewise.
* sysdeps/unix/sysv/linux/x86_64/64/libc.abilist [GLIBC_2.22]:
Likewise.
* sysdeps/unix/sysv/linux/x86_64/x32/libc.abilist [GLIBC_2.22]:
Likewise.
* sysdeps/unix/sysv/linux/hppa/libc.abilist [GLIBC_2.22]: Likewise.
* sysdeps/unix/sysv/linux/nios2/libc.abilist [GLIBC_2.22]: Likewise.
For maximum paranoia we run ld.so through the normal set
of tests for all of the shared libraries. This includes
running ld.so through check-localplt, check-textrel, and
check-execstack. While none of these should trigger any
failures given the way ld.so is built, it might possibly
fail if a developer does something wrong. This paranoia
was triggered by a discussion over the use of __strcpy
vs. strcpy [1] and if the symbol could leak and use the
libc.so version.
The check-localplt test fails right away because localplt.data
needs updating for all arches. By default we add 6 new symbols:
__tls_get_addr, __libc_memalign, malloc, calloc, realloc and
free. Other machines like i386, power, and s390 require some
different symbol sets e.g. ___tls_get_addr vs. __tls_get_addr
for i386.
Verified for i386
Verified for x86_64
Verified for ppc32
Verified for ppc64
Verified for ppc64le
Verified for arm
Verified for aarch64
Verified for s390
Verified for s390x
Guessed for alpha
Guessed for ia64
Guessed for m68k
Guessed for microblaze
Guessed for sparc32
Guessed for sparc64
Defaults for sh
Defaults for mips
Defaults for hppa
Defaults for tile
Machine manintainers notified to double check the data
used in localplt.data.
[1] https://sourceware.org/ml/libc-alpha/2014-10/msg00548.html
My recent changes that added libm_hidden_proto / libm_hidden_def for
fegetround had the side effect of removing the need for a
localplt.data entry for fegetround for powerpc-nofpu. This patch
removes that entry. Tested powerpc-nofpu.
* sysdeps/unix/sysv/linux/powerpc/powerpc32/nofpu/nptl/localplt.data:
Don't expect fegetround reference in libm.so.
Joseph Myers
Wilco Dijkstra
Florian Weimer
Mark Wielaard
Adhemerval Zanella
Carlos O'Donell
Roland McGrath
Allan McRae