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| -rw-r--r-- | NEWS | 279 |
1 files changed, 144 insertions, 135 deletions
@@ -7,142 +7,64 @@ using `glibc' in the "product" field. Version 2.26 +Major new features: + * 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). -* 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. - -* The rpcgen, librpcsvc and related headers will only be built and - installed when glibc is configured with --enable-obsolete-rpc. - This allows alternative RPC implementations, like TIRPC, to be used - by default. Applications needing features missing from TIRPC should - consider the rpcsvc-proto project developed by Thorsten Kukuk (SUSE). - -* The NIS(+) name service modules, libnss_nis, libnss_nisplus, and - libnss_compat, are deprecated, and will not be built or installed by - default. Replacement implementations based on TIRPC, which - additionally support IPv6, are available from - <https://github.com/thkukuk/libnss_{compat,nis,nisplus}>. - -* The NIS(+) support library, libnsl, is 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. - A replacement implementation based on TIRPC is available from - <https://github.com/thkukuk/libnsl>. Like the replacement NIS(+) - name service modules, the replacement supports IPv6, and it can be - coinstalled with the compatibility shared library from glibc. - -* New configure option --enable-obsolete-nsl will cause libnsl's - headers, and the NIS(+) name service modules, to be built and - installed. This option may be removed in a future release. - -* Extensive new collation tests for Hungarian locales based on - "The Rules of Hungarian Orthography, 12th edition" and the work of - Egmont Koblinger (Bug 18934). - -* 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 legacy cfree function has been removed. Applications should use the - free function instead. +* Collation of Hungarian has been overhauled and is now consistent with "The + Rules of Hungarian Orthography, 12th edition" (Bug 18934). Contributed by + Egmont Koblinger. -* posix_spawnattr_setflags now supports POSIX_SPAWN_SETSID flag to create a - new session ID for the posix_spawn and posix_spawnp. It is scheduled to - be added on next major revision of POSIX, so current support is enabled - with _GNU_SOURCE. +* Improvements to the DNS stub resolver, contributed by Florian Weimer: -* The minimum Linux kernel version that this version of the GNU C Library - can be used with on i[4567]86 and x86_64 is 3.2. A Linux 3.2 or later - kernel was already required on all other architectures. - -* The obsolete <sys/ultrasound.h> header file has been removed. + - glibc 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 port to Native Client running on ARMv7-A (--host=arm-nacl) has been - removed. + - glibc 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. -* <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 talk to us. - -* The obsolete signal constant SIGUNUSED is no longer defined by <signal.h>. - -* The reallocarray function has been added to libc. It is a realloc - replacement with a check for integer overflow when calculating total - allocation size. - -* New preadv2 and pwritev2 has been added. They are Linux extensions to - preadv and pwritev with an additional flag argument where it is possible - to set high priority or use O_DSYNC or O_SYNC for a specific IO operation. - For complete support it requires Linux kernel version 4.6, otherwise a - compat implementation will be used (which refuses all flags and routes it - to preadv or pwritev). - -* 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. - -* 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. This ensures correct synchronization - for the spin lock's operations and critical sections protected by a spin - lock. 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). + - When the “rotate” (RES_ROTATE) resolver option is active, glibc 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 to tweak behavior of the GNU C Library using the GLIBC_TUNABLES environment variable. -* The s390 specific ptrace requests are adjusted to the kernel ones. Request 12 - is now used for PTRACE_SINGLEBLOCK instead of PTRACE_GETREGS. The requests - PTRACE_GETREGS, PTRACE_SETREGS, PTRACE_GETFPREGS and PTRACE_SETFPREGS were - removed as those are not supported by the s390 kernel. The requests - 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 were added as those are supported - by the s390 kernel. +* 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. -* The minimum GCC version that can be used to build this version of the GNU - C Library is GCC 4.9. Older GCC versions, and non-GNU compilers, can - still be used to compile programs using the GNU C Library. +* 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. -* The minimum GNU Binutils version that can be used to build this version of - the GNU C Library is Binutils 2.25. +* On ia64, powerpc64le, x86-32, and x86-64, the math library now implements + 128-bit floating point as defined by IEEE 60559:2011 and ISO/IEC TS + 18661-3:2015. Support for more architectures will be added in future + releases. Contributed by Paul E. Murphy, Gabriel F. T. Gomes, and Tulio + Magno Quites Machado Filho. -* Support is added, on powerpc64le, x86_64, x86 and ia64, for interfaces - supporting the _Float128 type from ISO/IEC TS 18661-3:2015. Most of the - interfaces are taken from TS 18661-3. The type-generic macros in <math.h> - and <tgmath.h> support this type. The GNU C Library now requires GCC 6.2 - or later to build for powerpc64le. When used with GCC versions before GCC - 7, these interfaces may be used with the type under the non-standard name - __float128. + 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 prior to + version 7). New <stdlib.h> functions from ISO/IEC TS 18661-3: @@ -230,24 +152,111 @@ Version 2.26 - Exponential and Logarithmic Function: clog10f128. -* When the “rotate” (RES_ROTATE) DNS stub resolver option is active, glibc - will now randomly pick a name server from the configuration as a starting - point. (Previously, the second name server was always used.) +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 glibc 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, glibc 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. -* The glibc DNS stub resolver now supports an arbitary number of search - domains (configured using the “search” directive in /etc/resolv.conf). - Most applications will automatically benefit from this change, but for - backwards compatibility reasons, applications which directly modify _res - objects (which contain the resolver state, including the search list - array, which is limited to six entries) will only use the first six search - domains, as before. - -* The glibc DNS stub resolver now automatically reloads /etc/resolv.conf, - to pick up changed configuration settings. The new “no-reload” - (RES_NORELOAD) resolver option disables this behavior. +* <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 glibc. + +* On most architectures, GCC 4.9 or later is required to build glibc. On + powerpc64le, GCC 6.2 or later is required. + + Older GCC versions and non-GNU compilers are still supported when + compiling programs that use glibc. (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: |