delta/glibc.git/string/string.h, branch release/2.25/master

Update copyright dates with scripts/update-copyrights.

2017-01-01T00:14:16+00:00

New string function explicit_bzero (from OpenBSD).

2016-12-16T21:21:54+00:00

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.

Correct comments in string.h re strcoll_l, strxfrm_l.

2016-11-16T19:18:32+00:00

	* string/string.h: Remove obsolete comment stating that
	strcoll_l and strxfrm_l have not yet been standardized.

Support __STDC_WANT_LIB_EXT2__ feature test macro.

2016-08-02T17:40:35+00:00

This patch implements support for the __STDC_WANT_LIB_EXT2__ feature
test macro from ISO/IEC TR 24731-2:2010, thereby implementing one
possible approach for supporting ISO C feature test macros.

Recall that, as described in
, these
macros work based on the definition when affected headers are
included, so cannot be handled once when the first system header is
included because that might not be one of the headers the particular
macro in question affects.
 expresses
views on possible approaches for implementation and
 follows
up on that.

This patch arranges things so that the relevant condition is
__GLIBC_USE (LIB_EXT2), following one of the suggestions given.
Headers using these macros include , which
in turn includes .  Headers must define
__GLIBC_INTERNAL_STARTING_HEADER_IMPLEMENTATION before including
, to discourage inclusion outside glibc as
requested.  __USE_GNU conditions on affected functions are changed to
__GLIBC_USE (LIB_EXT2), while it's added as an additional alternative
on the conditions for functions already enabled for some POSIX
versions.

It would be possible to convert existing __USE_* conditionals to
__GLIBC_USE (with the relevant __GLIBC_USE_* being defined in
 where __USE_* are presently defined), and so make them
typo-proof (given -Wundef -Werror in glibc builds) because __GLIBC_USE
is used with #if not #ifdef / #if defined.

No attempt is made to enforce the rule about diagnosing different
definitions of __STDC_WANT_LIB_EXT2__ when affected headers are
included; such a diagnostic is incompatible with multiple-include
guards on the affected headers, unless compiler extensions are added
to support it.

As previously noted, glibc does not implement all features from TR
24731-2:2010: the functions aswprintf vaswprintf getwdelim getwline
are not in glibc, although they would be appropriate to add if someone
wished to do so.  But I think it makes sense to support the feature
test macro if *any* of the controlled features are present in glibc.

Tested for x86_64 and x86 (testsuite, and that installed stripped
shared libraries are unchanged by the patch).

	* bits/libc-header-start.h: New file.
	* Makefile (headers): Add bits/libc-header-start.h.
	* include/features.h (__STDC_WANT_LIB_EXT2__): Document.
	(__GLIBC_USE): New macro.
	* libio/stdio.h: Define
	__GLIBC_INTERNAL_STARTING_HEADER_IMPLEMENTATION and include
	 instead of including .
	(fmemopen): Declare also if [__GLIBC_USE (LIB_EXT2)].
	(open_memstream): Likewise.
	(vasprintf): Declare if [__GLIBC_USE (LIB_EXT2)], not [__USE_GNU].
	(__asprintf): Likewise.
	(asprintf): Likewise.
	(__getdelim): Declare also if [__GLIBC_USE (LIB_EXT2)].
	(getdelim): Likewise.
	(getline): Likewise.
	* string/string.h: Define
	__GLIBC_INTERNAL_STARTING_HEADER_IMPLEMENTATION and include
	 instead of including .
	(strdup): Declare also if [__GLIBC_USE (LIB_EXT2)]
	(strndup): Likewise.
	* wcsmbs/wchar.h: Define
	__GLIBC_INTERNAL_STARTING_HEADER_IMPLEMENTATION and include
	 instead of including .
	(open_wmemstream): Declare also if [__GLIBC_USE (LIB_EXT2)].
	* manual/creature.texi (__STDC_WANT_LIB_EXT2__): Document macro.

Remove pre GCC3.2 optimizations from string/bits/string2.h.

2016-04-15T11:46:05+00:00

        * string/string.h: Use __GNUC_PREREQ(3,4) for bits/string2.h.
        * string/bits/string2.h (__STRING2_SMALL_GET16): Remove.
        (__STRING2_SMALL_GET32): Remove.
        (memset): Remove.
        (__memset_1): Remove.
        (__memset_gc): Remove.
        (__mempcpy): Remove.
        (mempcpy): Remove.
        (__mempcpy_args): Remove.
        (strchr): Remove.
        (strcpy): Remove.
        (strcpy_args): Remove.
        (__stpcpy_args): Remove.
        (__strcmp_cc): Remove.
        (__strcmp_gc): Remove.
        (strstr): Remove.

Update copyright dates with scripts/update-copyrights.

2016-01-04T16:05:18+00:00

Improve performance of mempcpy by inlining and using memcpy. Enable

2015-08-05T15:24:04+00:00

this for all targets except sparc which has an optimized mempcpy
implementation.

Don't define __CORRECT_ISO_CPP_STRING_H_PROTO for non-GCC compilers (bug 17631)

2015-03-04T10:52:55+00:00

The implementation of __CORRECT_ISO_CPP_STRING_H_PROTO requires
support for asm aliases.

Update copyright dates with scripts/update-copyrights.

2015-01-02T16:29:47+00:00

Complete _BSD_SOURCE / _SVID_source followup cleanup.

2014-02-21T21:45:26+00:00

This patch completes the headers cleanup consequent on removal of
_BSD_SOURCE and _SVID_SOURCE (apart from any subsequent deprecations):

* #endif conditionals that referred to BSD or SVID are updated.

* Redundant __USE_* tests in cases involving __USE_MISC are removed.
  This includes cases such as __USE_MISC || __USE_ISOC99, where
  __USE_MISC is redundant (because __USE_MISC is only ever defined in
  the default / _DEFAULT_SOURCE / _GNU_SOURCE case, when __USE_ISOC99
  is also defined; the same applies to the non-XSI-extended POSIX
  versions), and cases involving __USE_GNU, where __USE_GNU is
  redundant (because if __USE_GNU is defined, so are the other __USE_*
  macros).  There may well be other cases of __USE_FOO || __USE_BAR
  tests that could be simplified because one macro implies the other;
  this patch only addresses cases involving __USE_MISC.

Tested x86_64.

	* bits/fcntl.h [__USE_MISC]: Remove redundant conditionals.
	* bits/sigaction.h [__USE_MISC]: Likewise.
	* bits/waitstatus.h: Update #endif comments.
	* ctype/ctype.h: Likewise.
	* dirent/dirent.h: Likewise.
	[__USE_MISC]: Remove redundant conditionals.
	* grp/grp.h: Update #endif comments.
	[__USE_GNU]: Remove redundant conditionals.
	[__USE_MISC]: Likewise.
	* inet/netinet/in.h [__USE_GNU]: Likewise.
	* io/sys/stat.h [__USE_MISC]: Likewise.
	* libio/bits/stdio-ldbl.h [__USE_MISC]: Likewise.
	* libio/bits/stdio.h: Update #endif comments.
	[__USE_MISC]: Remove redundant conditionals.
	* libio/bits/stdio2.h [__USE_MISC]: Likewise.
	* libio/stdio.h: Update #endif comments.
	[__USE_MISC]: Remove redundant conditionals.
	* math/bits/math-finite.h [__USE_MISC]: Likewise.
	* math/bits/mathcalls.h [__USE_MISC]: Likewise.
	* math/math.h: Update #else and #endif comments.
	[__USE_MISC]: Remove redundant conditionals.
	* misc/sys/uio.h: Update #endif comments.
	* posix/bits/unistd.h [__USE_MISC]: Remove redundant conditionals.
	* posix/glob.h [__USE_MISC]: Likewise.
	* posix/sys/types.h: Update #endif comments.
	[__USE_MISC]: Remove redundant conditionals.
	* posix/sys/wait.h: Update #endif comments.
	[__USE_MISC]: Remove redundant conditionals.
	* posix/unistd.h: Update #endif comments.
	[__USE_MISC]: Remove redundant conditionals.
	* pwd/pwd.h [__USE_GNU]: Likewise.
	[__USE_MISC]: Likewise.
	* resolv/netdb.h [__USE_GNU]: Likewise.
	* signal/signal.h: Update #endif comments.
	[__USE_MISC]: Remove redundant conditionals.
	* stdlib/stdlib.h: Update #else and #endif comments.
	[__USE_MISC]: Remove redundant conditionals.
	[__USE_GNU]: Likewise.
	* string/bits/string2.h [__USE_MISC]: Likewise.
	* string/string.h: Update #endif comments.
	[__USE_MISC]: Remove redundant conditionals.
	* sysdeps/m68k/m680x0/fpu/bits/mathinline.h [__USE_MISC]:
	Likewise.
	* sysdeps/mach/hurd/bits/fcntl.h [__USE_MISC]: Likewise.
	* sysdeps/mach/hurd/bits/stat.h [__USE_MISC]: Likewise.
	* sysdeps/unix/sysv/linux/alpha/bits/sigaction.h [__USE_MISC]:
	Likewise.
	* sysdeps/unix/sysv/linux/alpha/bits/stat.h [__USE_MISC]:
	Likewise.
	* sysdeps/unix/sysv/linux/bits/fcntl-linux.h: Update #endif
	comments.
	[__USE_MISC]: Remove redundant conditionals.
	* sysdeps/unix/sysv/linux/bits/in.h [__USE_GNU]: Likewise.
	* sysdeps/unix/sysv/linux/bits/sigaction.h [__USE_MISC]: Likewise.
	* sysdeps/unix/sysv/linux/bits/socket.h [__USE_GNU]: Likewise.
	* sysdeps/unix/sysv/linux/bits/stat.h [__USE_MISC]: Likewise.
	* sysdeps/unix/sysv/linux/ia64/bits/sigaction.h [__USE_MISC]:
	Likewise.
	* sysdeps/unix/sysv/linux/m68k/bits/stat.h [__USE_MISC]: Likewise.
	* sysdeps/unix/sysv/linux/mips/bits/sigaction.h [__USE_MISC]:
	Likewise.
	* sysdeps/unix/sysv/linux/mips/bits/stat.h [__USE_MISC]: Likewise.
	* sysdeps/unix/sysv/linux/powerpc/bits/stat.h [__USE_MISC]:
	Likewise.
	* sysdeps/unix/sysv/linux/s390/bits/sigaction.h [__USE_MISC]:
	Likewise.
	* sysdeps/unix/sysv/linux/s390/bits/stat.h [__USE_MISC]: Likewise.
	* sysdeps/unix/sysv/linux/sparc/bits/sigaction.h [__USE_MISC]:
	Likewise.
	* sysdeps/unix/sysv/linux/sparc/bits/stat.h [__USE_MISC]:
	Likewise.
	* sysdeps/unix/sysv/linux/x86/bits/stat.h [__USE_MISC]: Likewise.
	* sysdeps/x86/bits/string.h: Update #endif comments.
	* sysdeps/x86/fpu/bits/mathinline.h [__USE_MISC]: Remove redundant
	conditionals.
	* time/sys/time.h: Update #endif comments.
	* time/time.h: Likewise.
	[__USE_MISC]: Remove redundant conditionals.