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The GNU C Library version 2.26 is now available

• From: Siddhesh Poyarekar <siddhesh at sourceware dot org>
• To: "libc-alpha at sourceware dot org" <libc-alpha at sourceware dot org>
• Date: Wed, 2 Aug 2017 19:44:15 +0530
• Subject: The GNU C Library version 2.26 is now available
• Authentication-results: sourceware.org; auth=none
• Reply-to: siddhesh at sourceware dot org

The GNU C Library=================The GNU C Library version 2.26 is now available.The GNU C Library is used as *the* C library in the GNU system andin GNU/Linux systems, as well as many other systems that use Linuxas the kernel.The GNU C Library is primarily designed to be a portableand high performance C library.  It follows all relevantstandards including ISO C11 and POSIX.1-2008.  It is alsointernationalized and has one of the most completeinternationalization interfaces known.The GNU C Library webpage is athttp://www.gnu.org/software/libc/Packages for the 2.26 release may be downloaded from:http://ftpmirror.gnu.org/libc/http://ftp.gnu.org/gnu/libc/The mirror list is athttp://www.gnu.org/order/ftp.htmlNEWS for version 2.26=====================Major new features:* A per-thread cache has been added to malloc. Access to the cache requires  no locks and therefore significantly accelerates the fast path to allocate  and free small amounts of memory. Refilling an empty cache requireslocking  the underlying arena. Performance measurements show significant gains in a  wide variety of user workloads. Workloads were captured using a special  instrumented malloc and analyzed with a malloc simulator. Contributed by  DJ Delorie with the help of Florian Weimer, and Carlos O'Donell.* Unicode 10.0.0 Support: Character encoding, character type info, and  transliteration tables are all updated to Unicode 10.0.0, using  generator scripts contributed by Mike FABIAN (Red Hat).  These updates cause user visible changes, especially the changes in  wcwidth for many emoji characters cause problems when emoji sequences  are rendered with pango, see for example:https://bugzilla.gnome.org/show_bug.cgi?id=780669#c5* Collation of Hungarian has been overhauled and is now consistent with "The  Rules of Hungarian Orthography, 12th edition" (Bug 18934).  Contributed by  Egmont Koblinger.* Improvements to the DNS stub resolver, contributed by Florian Weimer:  - The GNU C Library will now detect when /etc/resolv.conf has been    modified and reload the changed configuration.  The new resolver option    “no-reload” (RES_NORELOAD) disables this behavior.  - The GNU C Library now supports an arbitrary number of search domains    (configured using the “search” directive in /etc/resolv.conf);    previously, there was a hard limit of six domains.  For backward    compatibility, applications that directly modify the ‘_res’ global    object are still limited to six search domains.  - When the “rotate” (RES_ROTATE) resolver option is active, the GNU C    Library will now randomly pick a name server from the configuration as a    starting point.  (Previously, the second name server was always used.)* The tunables feature is now enabled by default.  This allows users totweak  behavior of the GNU C Library using the GLIBC_TUNABLES environmentvariable.* New function reallocarray, which resizes an allocated block (like realloc)  to the product of two sizes, with a guaranteed clean failure upon integer  overflow in the multiplication.  Originally from OpenBSD, contributed by  Dennis Wölfing and Rüdiger Sonderfeld.* New wrappers for the Linux-specific system calls preadv2 and pwritev2.  These are extended versions of preadv and pwritev, respectively, taking an  additional flags argument.  The set of supported flags depends on the  running kernel; full support currently requires kernel 4.7 or later.* posix_spawnattr_setflags now supports the flag POSIX_SPAWN_SETSID, to  create a new session ID for the spawned process.  This feature is  scheduled to be added to the next major revision of POSIX; for the time  being, it is available under _GNU_SOURCE.* errno.h is now safe to use from C-preprocessed assembly language on all  supported operating systems.  In this context, it will only define the  Exxxx constants, as preprocessor macros expanding to integer literals.* On ia64, powerpc64le, x86-32, and x86-64, the math library now implements  128-bit floating point as defined by ISO/IEC/IEEE 60559:2011 (IEEE  754-2008) and ISO/IEC TS 18661-3:2015.  Contributed by Paul E. Murphy,  Gabriel F. T. Gomes, Tulio Magno Quites Machado Filho, and Joseph Myers.  To compile programs that use this feature, the compiler must support  128-bit floating point with the type name _Float128 (as defined by TS  18661-3) or __float128 (the nonstandard name used by GCC for C++, and for  C prior to version 7).  _GNU_SOURCE or __STDC_WANT_IEC_60559_TYPES_EXT__  must be defined to make the new interfaces visible.  The new functions and macros correspond to those present for other  floating-point types (except for a few obsolescent interfaces not  supported for the new type), with F128 or f128 suffixes; for example,  strtof128, HUGE_VAL_F128 and cosf128.  Following TS 18661-3, there are no  printf or scanf formats for the new type; the strfromf128 and strtof128  interfaces should be used instead.Deprecated and removed features, and other changes affecting compatibility:* The synchronization that pthread_spin_unlock performs has been changed to  now be equivalent to a C11 atomic store with release memory order to the  spin lock's memory location.  Previously, several (but not all)  architectures used stronger synchronization (e.g., containing what is  often called a full barrier).  This change can improve performance, but  may affect odd fringe uses of spin locks that depend on the previous  behavior (e.g., using spin locks as atomic variables to try to implement  Dekker's mutual exclusion algorithm).* The port to Native Client running on ARMv7-A (--host=arm-nacl) has been  removed.* Sun RPC is deprecated.  The rpcgen program, librpcsvc, and Sun RPC headers  will only be built and installed when the GNU C Library is configured with  --enable-obsolete-rpc.  This allows alternative RPC implementations, such  as TIRPC or rpcsvc-proto, to be used.* The NIS(+) name service modules, libnss_nis, libnss_nisplus, and  libnss_compat, are deprecated, and will not be built or installed by  default.  The NIS(+) support library, libnsl, is also deprecated.  By default, a  compatibility shared library will be built and installed, but not headers  or development libraries. Only a few NIS-related programs require this  library.  (In particular, the GNU C Library has never required programs  that use 'gethostbyname' to be linked with libnsl.)  Replacement implementations based on TIRPC, which additionally support  IPv6, are available from <https://github.com/thkukuk/>.  The configure  option --enable-obsolete-nsl will cause libnsl's headers, and the NIS(+)  name service modules, to be built and installed.* The DNS stub resolver no longer performs EDNS fallback.  If EDNS or DNSSEC  support is enabled, the configured recursive resolver must support EDNS.  (Responding to EDNS-enabled queries with responses which are not  EDNS-enabled is fine, but FORMERR responses are not.)* res_mkquery and res_nmkquery no longer support the IQUERY opcode.  DNS  servers have not supported this opcode for a long time.* The _res_opcodes variable has been removed from libresolv.  It had been  exported by accident.* <string.h> no longer includes inline versions of any string functions,  as this kind of optimization is better done by the compiler.  The macros  __USE_STRING_INLINES and __NO_STRING_INLINES no longer have any effect.* The nonstandard header <xlocale.h> has been removed.  Most programs should  use <locale.h> instead.  If you have a specific need for the definition of  locale_t with no other declarations, please contact  libc-alpha@sourceware.org and explain.* The obsolete header <sys/ultrasound.h> has been removed.* The obsolete signal constant SIGUNUSED is no longer defined by <signal.h>.* The obsolete function cfree has been removed.  Applications should use  free instead.* The stack_t type no longer has the name struct sigaltstack.  This changes  the C++ name mangling for interfaces involving this type.* The ucontext_t type no longer has the name struct ucontext.  This changes  the C++ name mangling for interfaces involving this type.* On M68k GNU/Linux and MIPS GNU/Linux, the fpregset_t type no longer has  the name struct fpregset.  On Nios II GNU/Linux, the mcontext_t type no  longer has the name struct mcontext.  On SPARC GNU/Linux, the struct  mc_fq, struct rwindow, struct fpq and struct fq types are no longer  defined in sys/ucontext.h, the mc_fpu_t type no longer has the name struct  mc_fpu, the gwindows_t type no longer has the name struct gwindows and the  fpregset_t type no longer has the name struct fpu.  This changes the C++  name mangling for interfaces involving those types.* On S/390 GNU/Linux, the constants defined by <sys/ptrace.h> have been  synced with the kernel:    - PTRACE_GETREGS, PTRACE_SETREGS, PTRACE_GETFPREGS and PTRACE_SETFPREGS      are not supported on this architecture and have been removed.    - PTRACE_SINGLEBLOCK, PTRACE_SECCOMP_GET_FILTER, PTRACE_PEEKUSR_AREA,      PTRACE_POKEUSR_AREA, PTRACE_GET_LAST_BREAK, PTRACE_ENABLE_TE,      PTRACE_DISABLE_TE and PTRACE_TE_ABORT_RAND have been added.  Programs that assume the GET/SETREGS ptrace requests are universally  available will now fail to build, instead of malfunctioning at runtime.Changes to build and runtime requirements:* Linux kernel 3.2 or later is required at runtime, on all architectures  supported by that kernel.  (This is a change from version 2.25 only for  x86-32 and x86-64.)* GNU Binutils 2.25 or later is now required to build the GNU C Library.* On most architectures, GCC 4.9 or later is required to build the GNU C  Library.  On powerpc64le, GCC 6.2 or later is required.  Older GCC versions and non-GNU compilers are still supported when  compiling programs that use the GNU C Library.  (We do not know exactly  how old, and some GNU extensions to C may be _de facto_ required.  If you  are interested in helping us make this statement less vague, please  contact libc-alpha@sourceware.org.)Security related changes:* The DNS stub resolver limits the advertised UDP buffer size to 1200 bytes,  to avoid fragmentation-based spoofing attacks (CVE-2017-12132).* LD_LIBRARY_PATH is now ignored in binaries running in privileged AT_SECURE  mode to guard against local privilege escalation attacks(CVE-2017-1000366).* Avoid printing a backtrace from the __stack_chk_fail function since it is  called on a corrupt stack and a backtrace is unreliable on a corrupt stack  (CVE-2010-3192).* A use-after-free vulnerability in clntudp_call in the Sun RPC systemhas been  fixed (CVE-2017-12133).Contributors============This release was made possible by the contributions of many people.The maintainers are grateful to everyone who has contributedchanges or bug reports.  These include:Adhemerval ZanellaAkhilesh KumarAlan ModraAlexey NeymanAndreas SchwabArjun ShankarBenjamin CamaCarlos O'DonellChris LeonardChristian BorntraegerChristian BraunerChristopher ChittleboroughChung-Lin TangDJ DelorieDennis WölfingDmitry BilunovDmitry V. LevinEgmont KoblingerEyolf ØstremFlorian WeimerGabriel F. T. GomesGordana CmiljanovicH.J. LuIhar HrachyshkaIvo RaisrJiong WangJohn David AnglinJoseph MyersJustus WinterKir KolyshkinMarko MyllynenMassimeddu CiredduMatthew KrupcaleMike FABIANMike FrysingerMousa MoradiNathan RossiPaul ClarkePaul E. MurphyPaul EggertPeng WuPhil BlundellPrakhar BahugunaRabin VincentRafal LuzynskiRajalakshmi SrinivasaraghavanRical JasanRogerio A. CardosoSamuel ThibaultSanthosh ThottingalSiddhesh PoyarekarSlava BarinovStefan LieblerSteve EllceySunyeop LeeSzabolcs NagyThorsten KukukTulio Magno Quites Machado FilhoUros BizjakVladimir MezentsevWainer dos Santos MoschettaWilco DijkstraWladimir J. van der LaanYury NorovZack Weinberg