glibc/include
Joseph Myers d709042a6e Fix lgamma setting signgam for ISO C (bug 15421).
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.
2015-11-20 22:49:59 +00:00
..
arpa Fix resolver inet_* namespace (bug 17722). 2014-12-17 18:09:11 +00:00
bits Remove include/bits/ipc.h. 2015-06-18 23:08:15 +00:00
gnu Update copyright dates with scripts/update-copyrights. 2015-01-02 16:29:47 +00:00
net Fix resolver if_* namespace (bug 17717). 2014-12-16 18:18:49 +00:00
netinet Fix gethostbyaddr in6addr_any, in6addr_loopback namespace (bug 18532). 2015-06-17 20:08:22 +00:00
programs Update copyright dates with scripts/update-copyrights. 2015-01-02 16:29:47 +00:00
protocols
rpc Rename bits/libc-tsd.h to libc-tsd.h (bug 14912). 2015-09-03 20:33:46 +00:00
rpcsvc
sys Mark ld.so internel __fxstatat64 hidden 2015-10-19 12:01:48 -07:00
aio.h First steps to get conformtest fully working 2012-02-25 23:18:39 -05:00
aliases.h Remove pre-ISO C support 2012-01-07 23:57:22 -05:00
alloca.h alloca: fix buf interaction 2015-02-24 13:29:40 -05:00
argp.h
argz.h Remove use of INTDEF/INTUSE in intl 2012-05-24 23:08:18 +02:00
assert.h Remove NOT_IN_libc 2014-11-24 15:03:45 +05:30
atomic.h Move bits/atomic.h to atomic-machine.h (bug 14912). 2015-09-11 20:00:19 +00:00
byteswap.h
caller.h Update copyright dates with scripts/update-copyrights. 2015-01-02 16:29:47 +00:00
complex.h conformtest: Fix namespace testing. 2013-09-04 20:47:21 +00:00
cpio.h Add more headers to include/ for conform tests. 2014-12-11 21:41:30 +00:00
ctype.h Rename bits/libc-tsd.h to libc-tsd.h (bug 14912). 2015-09-03 20:33:46 +00:00
des.h
dirent.h Mark internal dirent functions hidden 2015-10-15 14:15:41 -07:00
dlfcn.h Mark _dl_catch_error hidden 2015-10-15 14:13:50 -07:00
elf.h Check supported DF_1_XXX bits 2012-11-21 06:33:19 -08:00
endian.h
envz.h
err.h
errno.h Remove NOT_IN_libc 2014-11-24 15:03:45 +05:30
error.h
execinfo.h Remove pre-ISO C support 2012-01-07 23:57:22 -05:00
fcntl.h Mark internal fcntl functions hidden 2015-10-15 14:16:41 -07:00
features.h Fix features.h for -Wundef (bug 19212). 2015-11-05 21:19:37 +00:00
fenv.h Mark fegetround pure (bug 16296). 2015-09-15 20:36:50 +00:00
fmtmsg.h Add more headers to include/ for conform tests. 2014-12-11 21:41:30 +00:00
fnmatch.h First steps to get conformtest fully working 2012-02-25 23:18:39 -05:00
fpu_control.h
ftw.h
gconv.h
getopt_int.h
getopt.h
glob.h First steps to get conformtest fully working 2012-02-25 23:18:39 -05:00
gmp.h
gnu-versions.h Update copyright dates with scripts/update-copyrights. 2015-01-02 16:29:47 +00:00
grp.h First steps to get conformtest fully working 2012-02-25 23:18:39 -05:00
gshadow.h [BZ #9955] 2009-04-23 18:29:30 +00:00
iconv.h
ifaddrs.h Remove IS_IN_nscd 2014-11-24 11:41:44 +05:30
ifunc-impl-list.h Update copyright dates with scripts/update-copyrights. 2015-01-02 16:29:47 +00:00
inline-hashtab.h Update copyright dates with scripts/update-copyrights. 2015-01-02 16:29:47 +00:00
langinfo.h Add first fixes for conformtest for POSIX2008 2012-02-26 21:32:56 -05:00
libc-internal.h Use max_align_t from <stddef.h>. 2015-10-29 12:46:22 +00:00
libc-symbols.h Remove .weak, .weakext configure tests. 2015-10-19 12:06:00 +00:00
libgen.h
libintl.h Remove use of INTDEF/INTUSE in intl 2012-05-24 23:08:18 +02:00
libio.h Rename bits/stdio-lock.h to stdio-lock.h (bug 14912). 2015-09-04 16:21:14 +00:00
limits.h Update copyright dates with scripts/update-copyrights. 2015-01-02 16:29:47 +00:00
link.h Move bits/libc-lock.h and bits/libc-lockP.h out of bits/ (bug 14912). 2015-09-08 21:11:03 +00:00
list.h Update copyright dates with scripts/update-copyrights. 2015-01-02 16:29:47 +00:00
locale.h First steps to get conformtest fully working 2012-02-25 23:18:39 -05:00
malloc.h * malloc/malloc.c (_int_free): Second argument is now mchunkptr. 2009-02-07 22:01:49 +00:00
math.h Fix lgamma setting signgam for ISO C (bug 15421). 2015-11-20 22:49:59 +00:00
mcheck.h
memory.h
mntent.h Remove use of INTUSE/INTDEF in misc. 2012-05-31 13:10:02 +02:00
monetary.h Add first fixes for conformtest for POSIX2008 2012-02-26 21:32:56 -05:00
mqueue.h Fix mq_receive, mq_send mq_timed* namespace (bug 18545). 2015-06-17 20:19:04 +00:00
netdb.h Fix h_errno namespace (bug 18520). 2015-06-12 10:10:18 +00:00
netgroup.h
nl_types.h
nss.h Harden putpwent, putgrent, putspent, putspent against injection [BZ #18724] 2015-10-02 11:34:13 +02:00
nsswitch.h
obstack.h
poll.h
printf.h
pthread.h Fix mq_notify pthread_barrier_* namespace (bug 18544). 2015-06-17 20:16:56 +00:00
pty.h
pwd.h Harden putpwent, putgrent, putspent, putspent against injection [BZ #18724] 2015-10-02 11:34:13 +02:00
regex.h First steps to get conformtest fully working 2012-02-25 23:18:39 -05:00
resolv.h Remove NOT_IN_libc 2014-11-24 15:03:45 +05:30
rounding-mode.h Update copyright dates with scripts/update-copyrights. 2015-01-02 16:29:47 +00:00
sched.h First steps to get conformtest fully working 2012-02-25 23:18:39 -05:00
scratch_buffer.h Use max_align_t from <stddef.h>. 2015-10-29 12:46:22 +00:00
search.h Fix sem_* tdelete, tfind, tsearch, twalk namespace (bug 18536). 2015-06-17 20:11:58 +00:00
set-hooks.h Update copyright dates with scripts/update-copyrights. 2015-01-02 16:29:47 +00:00
setjmp.h Mark internal setjmp functions hidden 2015-10-15 14:22:25 -07:00
sgtty.h
shadow.h Remove pre-ISO C support 2012-01-07 23:57:22 -05:00
shlib-compat.h Update copyright dates with scripts/update-copyrights. 2015-01-02 16:29:47 +00:00
signal.h Mark ld.so internel sigaction functions hidden 2015-10-15 14:23:31 -07:00
spawn.h
stab.h
stackinfo.h Update copyright dates with scripts/update-copyrights. 2015-01-02 16:29:47 +00:00
stap-probe.h include/stap-probe.h: Fix formatting. 2015-10-14 11:35:31 -04:00
stdc-predef.h Amendments to Unicode 7 update. 2015-02-23 11:35:24 -03:00
stdio_ext.h Remove use of INTDEF/INTUSE in libio 2012-05-24 23:06:20 +02:00
stdio.h Provide __libc_fatal for rtld. 2015-07-09 15:32:32 -07:00
stdlib.h Mark ld.so internel stdlib functions hidden 2015-10-15 14:24:35 -07:00
string.h Mark ld.so internel string functions hidden 2015-10-15 14:26:00 -07:00
strings.h
stropts.h First steps to get conformtest fully working 2012-02-25 23:18:39 -05:00
stubs-prologue.h
syscall.h
sysexits.h
syslog.h
tar.h
termios.h First steps to get conformtest fully working 2012-02-25 23:18:39 -05:00
tgmath.h
time.h Fix symbol definitions for __clock_* functions 2013-06-11 11:11:11 +05:30
ttyent.h Fix ttyslot namespace (bug 18547). 2015-06-17 20:21:19 +00:00
uchar.h First steps to get conformtest fully working 2012-02-25 23:18:39 -05:00
ucontext.h
ulimit.h First steps to get conformtest fully working 2012-02-25 23:18:39 -05:00
unistd.h Assume that SOCK_CLOEXEC is available and works 2015-10-17 12:02:37 +02:00
utime.h First steps to get conformtest fully working 2012-02-25 23:18:39 -05:00
utmp.h Remove pre-ISO C support 2012-01-07 23:57:22 -05:00
values.h Update copyright dates with scripts/update-copyrights. 2015-01-02 16:29:47 +00:00
wchar.h Fix swscanf vswscanf namespace (bug 18542). 2015-06-17 20:15:22 +00:00
wctype.h Fix regex wctype namespace (bug 18495). 2015-06-05 20:04:47 +00:00
wordexp.h First steps to get conformtest fully working 2012-02-25 23:18:39 -05:00
xlocale.h