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Version 2.35

Major new features:

* Unicode 14.0.0 Support: Character encoding, character type info, and
  transliteration tables are all updated to Unicode 14.0.0, using
  generator scripts contributed by Mike FABIAN (Red Hat).

* Bump r_version in the debugger interface to 2 and add a new field,
  r_next, support multiple namespaces.

* Support for the C.UTF-8 locale has been added to glibc.  The locale
  supports full code-point sorting for all valid Unicode code points.  A
  limitation in the framework for fnmatch, regexec, and regcomp requires
  a compromise to save space and only ASCII-based range expressions are
  supported for now (see bug 28255).  The full size of the locale is
  only ~400KiB, with 346KiB coming from LC_CTYPE information for
  Unicode.  This locale harmonizes downstream C.UTF-8 already shipping
  in various downstream distributions.  The locale is not built into
  glibc, and must be installed.

* <math.h> functions that round their results to a narrower type, and
  corresponding <tgmath.h> macros, are added from TS 18661-1:2014, TS
  18661-3:2015 and draft ISO C2X:

  - fsqrt, fsqrtl, dsqrtl and corresponding fMsqrtfN, fMsqrtfNx,
    fMxsqrtfN and fMxsqrtfNx functions.

  - ffma, ffmal, dfmal and corresponding fMfmafN, fMfmafNx, fMxfmafN and
    fMxfmafNx functions.

* <math.h> functions for floating-point maximum and minimum,
  corresponding to new operations in IEEE 754-2019, and corresponding
  <tgmath.h> macros, are added from draft ISO C2X: fmaximum,
  fmaximum_num, fmaximum_mag, fmaximum_mag_num, fminimum, fminimum_num,
  fminimum_mag, fminimum_mag_num and corresponding functions for float,
  long double, _FloatN and _FloatNx.

* <math.h> macros for single-precision float constants are added as a
  GNU extension: M_Ef, M_LOG2Ef, M_LOG10Ef, M_LN2f, M_LN10f, M_PIf,
  M_PI_2f, M_PI_4f, M_1_PIf, M_2_PIf, M_2_SQRTPIf, M_SQRT2f and
  M_SQRT1_2f.

* The __STDC_IEC_60559_BFP__ and __STDC_IEC_60559_COMPLEX__ macros are
  predefined as specified in TS 18661-1:2014.

* The exp10 functions in <math.h> now have a corresponding type-generic
  macro in <tgmath.h>.

* The ISO C2X macro _PRINTF_NAN_LEN_MAX has been added to <stdio.h>.

* printf-family functions now support the %b format for output of
  integers in binary, as specified in draft ISO C2X, and the %B variant
  of that format recommended by draft ISO C2X.

* A new DSO sorting algorithm has been added in the dynamic linker that uses
  topological sorting by depth-first search (DFS), solving performance issues
  of the existing sorting algorithm when encountering particular circular
  object dependency cases.

* A new tunable, glibc.rtld.dynamic_sort, can be used to select between
  the two DSO sorting algorithms.  The default setting of '2' uses the
  new DFS-based algorithm.  The setting '1' switches to the old
  algorithm used in glibc 2.33 and earlier.

* ABI support for a new function '__memcmpeq'. '__memcmpeq' is meant
  to be used by compilers for optimizing usage of 'memcmp' when its
  return value is only used for its boolean status.

* Support for automatically registering threads with the Linux rseq
  system call has been added.  This system call is implemented starting
  from Linux 4.18.  The Restartable Sequences ABI accelerates user-space
  operations on per-cpu data.  It allows user-space to perform updates
  on per-cpu data without requiring heavy-weight atomic operations.
  Automatically registering threads allows all libraries, including
  libc, to make immediate use of the rseq support by using the
  documented ABI, via the __rseq_flags, __rseq_offset, and __rseq_size
  variables.  The GNU C Library manual has details on integration of
  Restartable Sequences.

* A symbolic link to the dynamic linker is now installed under
  /usr/bin/ld.so (or more precisely, '${bindir}/ld.so').

* All programs and the testsuite in glibc are now built as position independent
  executables (PIE) by default on toolchains and architectures that support it.
  Further, if the toolchain and architecture supports it, even static programs
  are built as PIE and the resultant glibc can be used to build static PIE
  executables.  A new option --disable-default-pie has been added to disable
  this behavior and get a non-PIE build.  This option replaces
  --enable-static-pie, which no longer has any effect on the build
  configuration.

* On Linux, a new tunable, glibc.malloc.hugetlb, can be used to
  either make malloc issue madvise plus MADV_HUGEPAGE on mmap and sbrk
  or to use huge pages directly with mmap calls with the MAP_HUGETLB
  flags).  The former can improve performance when Transparent Huge Pages
  is set to 'madvise' mode while the latter uses the system reserved
  huge pages.

* The printf family of functions now handles the flagged %#m conversion
  specifier, printing errno as an error constant (similar to strerrorname_np).

* The function _dl_find_object has been added.  In-process unwinders
  can use it to efficiently locate unwinding information for a code
  address.

* Support for OpenRISC running on Linux has been added.  This port requires
  as least binutils 2.35, GCC 11, and Linux 5.4.  Currently only soft-float
  ABI is supported:

    - or1k-linux-gnu

  The OpenRISC ABI is 32-bit big-endian and uses 64-bit time (y2038 safe) and
  64-bit file offsets (LFS default).

* A new configure option, --with-rtld-early-cflags, can be used to
  specify additional compiler flags for building the early startup code
  of the dynamic linker.  On targets which have CPU compatibility
  checks, this can help to ensure that proper diagnostics are printed if
  the dynamic loader runs on an incompatible CPU.

* On Linux, the epoll_pwait2 function has been added.  It is similar to
  epoll_wait with the difference the timeout has nanoseconds resolution.

* The function posix_spawn_file_actions_addtcsetpgrp_np has been added,
  enabling posix_spawn and posix_spawnp to set the controlling terminal in
  the new process in a race free manner.  This function is a GNU extension.

* Source fortification (_FORTIFY_SOURCE) level 3 is now available for
  applications compiling with glibc and gcc 12 and later. Level 3 leverages
  the __builtin_dynamic_object_size function to deliver additional
  fortification balanced against additional runtime cost (checking non-constant
  bounds).

Deprecated and removed features, and other changes affecting compatibility:

* On x86-64, the LD_PREFER_MAP_32BIT_EXEC environment variable support
  has been removed since the first PT_LOAD segment is no longer executable
  due to defaulting to -z separate-code.

* The r_version update in the debugger interface makes the glibc binary
  incompatible with GDB binaries built without the following commits:

  c0154a4a21a gdb: Don't assume r_ldsomap when r_version > 1 on Linux
  4eb629d50d4 gdbserver: Check r_version < 1 for Linux debugger interface

  when audit modules or dlmopen are used.

* Intel MPX support (lazy PLT, ld.so profile, and LD_AUDIT) has been removed.

* The --enable-static-pie option is no longer available.  The glibc build
  configuration script now automatically detects static-pie support in the
  toolchain and architecture and enables it if available.

* The catchsegv script and associated libSegFault.so shared object have
  been removed.  There are widely-deployed out-of-process alternatives for
  catching coredumps and backtraces.

* Support for prelink will be removed in the next release; this includes
  removal of the LD_TRACE_PRELINKING, and LD_USE_LOAD_BIAS, environment
  variables and their functionality in the dynamic loader.

Changes to build and runtime requirements:

* The audit module interface version LAV_CURRENT is increased to enable
  proper bind-now support.  The loader now advertises via the la_symbind
  flags that PLT trace is not possible.  New audit modules require the
  new dynamic loader supporing the latest LAV_CURRENT version. Old audit
  modules are still loaded for all targets except aarch64.

* The audit interface on aarch64 is extended to support both the indirect
  result location register (x8) and NEON Q register.  Old audit modules are
  rejected by the loader.  Audit modules must be rebuilt to use the newer
  structure sizes and the latest module interface version for LAV_CURRENT.

Security related changes:

  CVE-2022-23219: Passing an overlong file name to the clnt_create
  legacy function could result in a stack-based buffer overflow when
  using the "unix" protocol.  Reported by Martin Sebor.

  CVE-2022-23218: Passing an overlong file name to the svcunix_create
  legacy function could result in a stack-based buffer overflow.

  CVE-2021-3998: Passing a path longer than PATH_MAX to the realpath
  function could result in a memory leak and potential access of
  uninitialized memory.  Reported by Qualys.

  CVE-2021-3999: Passing a buffer of size exactly 1 byte to the getcwd
  function may result in an off-by-one buffer underflow and overflow
  when the current working directory is longer than PATH_MAX and also
  corresponds to the / directory through an unprivileged mount
  namespace.  Reported by Qualys.

The following bugs are resolved with this release:

  [12889] nptl: Race condition in pthread_kill
  [14232] nptl: tst-cancel7 and tst-cancelx7 race condition
  [14913] libc: [mips] Clean up MIPS 64-bit register-dump.h output
  [15310] dynamic-link: _dl_sort_fini is O(n^3) causing slow exit when
    many dsos
  [15333] libc: Use 64-bit stat functions in installed programs
  [15533] dynamic-link: LD_AUDIT introduces an avoidable performance
    degradation
  [15971] dynamic-link: No interface for debugger access to libraries
    loaded with dlmopen
  [17318] locale: [RFE] Provide a C.UTF-8 locale by default
  [17645] dynamic-link: RFE: Improve performance of dynamic loader for
    deeply nested DSO dependencies.
  [19193] nptl: pthread_kill, pthread_cancel return ESRCH for a thread
    ID whose lifetime has not ended
  [22542] network: buffer overflow in sunrpc clnt_create
    (CVE-2022-23219)
  [22716] malloc: [PATCH] mtrace.pl: use TRACE_PRELINKING instead of
    TRACE_LOADED_OBJECTS
  [25947] malloc: memory leak in muntrace
  [26045] math: fmaxf(inf, nan) does not always work
  [26108] math: exp10() has problems with <tgmath.h>
  [26779] build: benign use after realloc at localealias.c:329
  [27609] dynamic-link: [2.32/2.33/2.34 Regression] In elf/dl-open.c
    (_dl_open) we might use __LM_ID_CALLER to index GL(dl_ns)[]
  [27945] build: build-many-glibcs.py doesn't configure GCC with
    --enable-initfini-array
  [27991] build: x86: sysdeps/x86/configure.ac breaks when
    libc_cv_include_x86_isa_level is loaded from cache
  [28036] nptl: Incorrect types for pthread_mutexattr_set/getrobust_np
    in __REDIRECT_NTH macro
  [28061] dynamic-link: A failing dlmopen called by an auditor crashed
  [28062] dynamic-link: Suppress audit calls when a (new) namespace is
    empty
  [28126] libc: nftw aborts for paths longer than PATH_MAX
  [28129] dynamic-link: Unnecessary check DT_DEBUG in ld.so
  [28153] libc: [test] gmon/tst-gmon-gprof* may have a f3 line when
    built with ld.lld
  [28182] libc: _TIME_BITS=64 in C++ has issues with fcntl, ioctl, prctl
  [28185] math: Inaccurate j0f function (again)
  [28199] locale: iconvconfig prefix flag behaves differently in glibc
    2.34
  [28203] dynamic-link: aarch64: elf_machine_{load_address,dynamic}
    should drop _GLOBAL_OFFSET_TABLE_[0] in favor of __ehdr_start for
    robustness
  [28213] librt: NULL pointer dereference in mq_notify (CVE-2021-38604)
  [28223] libc: mips: clone does not align stack
  [28253] dynamic-link: Missing colon in LD_SHOW_AUXV output after
    AT_MINSIGSTKSZ
  [28256] malloc: Conditional jump or move depends on uninitialised
    value(s) in __GI___tunables_init
  [28260] build: io/tst-closefrom, misc/tst-close_range, posix/tst-
    spawn5 fail if stray fds are open
  [28310] libc: Do not use affinity mask for sysconf
    (_SC_NPROCESSORS_CONF)
  [28338] time: undefined behavior in __tzfile_compute with oddball TZif
    file
  [28340] dynamic-link: ld.so crashes while loading a DSO with a read-
    only dynamic section
  [28349] libc: Segfault for ping -R on qemux86 caused by recvmsg()
  [28350] libc: ping receives SIGABRT on lib32-qemux86-64 caused by
    recvmsg()
  [28353] network: Race condition on __opensock
  [28357] dynamic-link: deadlock between pthread_create and ctors
  [28358] math: f64xdivf128 and f64xmulf128 spurious underflows
  [28361] nptl: Fix for bug 12889 causes setxid deadlock
  [28368] build: -Waddress instances in stdio-common/vfprintf-internal.c
  [28390] localedata: Update locale data to Unicode 14.0.0
  [28397] math: tgmath.h should not define fmaxmag, fminmag macros for
    C2X
  [28400] libc: [2.35 Regression] string/test-strncasecmp: cannot set
    locale "en_US.UTF-8"
  [28407] nptl: pthread_kill assumes that kill (getpid ()) is equivalent
    to tgkill (getpid (), gettid())
  [28455] dynamic-link: -Wl,--enable-new-dtags doesn't work
  [28457] dynamic-link: Missing reldepmod4.so dependency for
    globalmod1.so
  [28469] time: linux: struct timex is not correctly set for 32-bit
    systems with TIMESIZE=64
  [28470] regex: Buffer read overrun in regular expression searching
  [28475] string: Incorrect access attribute on memfrob
  [28524] libc: Conversion from ISO-2022-JP-3 with iconv may emit
    spurious NUL character on state reset
  [28532] libc: powerpc64[le]: CFI for assembly templated syscalls is
    incorrect
  [28550] dynamic-link: FAIL: tst-dso-
    ordering9_112-ecbda(GLIBC_TUNABLES=glibc.rtld.dynamic_sort=1)
    execution test
  [28554] build: Undefined generate-md5
  [28572] libc: Misaligned accesses in test-memcpy and test-mempcpy on
    hppa
  [28607] nptl: Masked signals are delivered on thread exit
  [28624] libc: openjdk 8/9 assume uni processor and gets stuck due to
    lack of cpu counting /proc fallback with glibc 2.34
  [28646] string: [2.35 Regression] mock -r fedora-36-x86_64
    /tmp/java-1.8.0-openjdk-1.8.0.312.b07-2.fc36.src.rpm& fails to build
  [28648] dynamic-link: Running ld.so on statically linked binaries
    crashes
  [28656] dynamic-link: LD_PREFER_MAP_32BIT_EXEC no longer works due to
    binutils changes
  [28676] dynamic-link: p_align on PT_LOAD segment in DSO isn't honored
  [28678] nptl: nptl/tst-create1 hangs sporadically
  [28688] dynamic-link: PT_LOAD p_align check is too strict
  [28700] nss: "dns [!UNAVAIL=return] files" default for hosts database
    is not useful
  [28707] time: assert in tzfile.c __tzfile_read striking with truncated
    timezones generated by tzcode-2021d and later
  [28713] math: GCC 12 miscompiles libm
  [28732] dynamic-link: FAIL: elf/tst-dl_find_object
  [28738] build: LIBC_LINKER_FEATURE doesn't work on linker -z option
  [28745] dynamic-link: _dl_find_object miscompilation on powerpc64le
  [28746] libc: _FORTIFY_SOURCE does not work for stpcpy
  [28749] libc: Inconsistency detected by ld.so: rtld.c: 1632: dl_main:
    Assertion `GL(dl_rtld_map).l_libname' failed!
  [28755] string: overflow bug in wcsncmp_avx2 and wcsncmp_evex
  [28757] nptl: GDB printer tests failed with new GDB
  [28765] math: x86_64 libmvec atan2 accuracy
  [28766] manual: Document libmvec accuracy
  [28768] network: Buffer overflow in svcunix_create with long pathnames
    (CVE-2022-23218)
  [28769] libc: Off-by-one buffer overflow/underflow in getcwd()
    (CVE-2021-3999)
  [28770] libc: Unexpected return value from realpath() for too long
    results (CVE-2021-3998)
  [28771] libc: %ebx optimization macros are incompatible with .altmacro
    in Systemtap probes
  [28780] build: --disable-default-pie doesn't work on static programs
  [28782] libc: x86-64 ISA level for glibc itself is always
    x86-64-baseline
  [28792] glob: possible wrong behaviour with patterns with double [
    with no closing ]
  [28837] libc: FAIL: socket/tst-socket-timestamp-compat
  [28847] locale: Empty mon_decimal_point in LC_MONETARY results in non-
    empty mon_decimal_point_wc


Version 2.34

Major new features:

* In order to support smoother in-place-upgrades and to simplify
  the implementation of the runtime all functionality formerly
  implemented in the libraries libpthread, libdl, libutil, libanl has
  been integrated into libc.  New applications do not need to link with
  -lpthread, -ldl, -lutil, -lanl anymore.  For backwards compatibility,
  empty static archives libpthread.a, libdl.a, libutil.a, libanl.a are
  provided, so that the linker options keep working.  Applications which
  have been linked against glibc 2.33 or earlier continue to load the
  corresponding shared objects (which are now empty).  The integration
  of those libraries into libc means that additional symbols become
  available by default.  This can cause applications that contain weak
  references to take unexpected code paths that would only have been
  used in previous glibc versions when e.g. preloading libpthread.so.0,
  potentially exposing application bugs.

* When _DYNAMIC_STACK_SIZE_SOURCE or _GNU_SOURCE are defined,
  PTHREAD_STACK_MIN is no longer constant and is redefined to
  sysconf(_SC_THREAD_STACK_MIN).  This supports dynamic sized register
  sets for modern architectural features like Arm SVE.

* Add _SC_MINSIGSTKSZ and _SC_SIGSTKSZ.  When _DYNAMIC_STACK_SIZE_SOURCE
  or _GNU_SOURCE are defined, MINSIGSTKSZ and SIGSTKSZ are no longer
  constant on Linux.  MINSIGSTKSZ is redefined to sysconf(_SC_MINSIGSTKSZ)
  and SIGSTKSZ is redefined to sysconf (_SC_SIGSTKSZ).  This supports
  dynamic sized register sets for modern architectural features like
  Arm SVE.

* The dynamic linker implements the --list-diagnostics option, printing
  a dump of information related to IFUNC resolver operation and
  glibc-hwcaps subdirectory selection.

* On Linux, the function execveat has been added.  It operates similar to
  execve and it is is already used to implement fexecve without requiring
  /proc to be mounted.  However, different than fexecve, if the syscall is not
  supported by the kernel an error is returned instead of trying a fallback.

* The ISO C2X function timespec_getres has been added.

* The feature test macro __STDC_WANT_IEC_60559_EXT__, from draft ISO
  C2X, is supported to enable declarations of functions defined in Annex F
  of C2X.  Those declarations are also enabled when
  __STDC_WANT_IEC_60559_BFP_EXT__, as specified in TS 18661-1, is
  defined, and when _GNU_SOURCE is defined.

* On powerpc64*, glibc can now be compiled without scv support using the
  --disable-scv configure option.

* Add support for 64-bit time_t on configurations like x86 where time_t
  is traditionally 32-bit.  Although time_t still defaults to 32-bit on
  these configurations, this default may change in future versions.
  This is enabled with the _TIME_BITS preprocessor macro set to 64 and is
  only supported when LFS (_FILE_OFFSET_BITS=64) is also enabled.  It is
  only enabled for Linux and the full support requires a minimum kernel
  version of 5.1.

* The main gconv-modules file in glibc now contains only a small set of
  essential converter modules and the rest have been moved into a supplementary
  configuration file gconv-modules-extra.conf in the gconv-modules.d directory
  in the same GCONV_PATH.  Similarly, external converter modules directories
  may have supplementary configuration files in a gconv-modules.d directory
  with names ending with .conf to logically classify the converter modules in
  that directory.

* On Linux, a new tunable, glibc.pthread.stack_cache_size, can be used
  to configure the size of the thread stack cache.

* The function _Fork has been added as an async-signal-safe fork replacement
  since Austin Group issue 62 droped the async-signal-safe requirement for
  fork (and it will be included in the future POSIX standard).  The new _Fork
  function does not run any atfork function neither resets any internal state
  or lock (such as the malloc one), and only sets up a minimal state required
  to call async-signal-safe functions (such as raise or execve).  This function
  is currently a GNU extension.

* On Linux, the close_range function has been added.  It allows efficiently
  closing a range of file descriptors on recent kernels (version 5.9).

* The function closefrom has been added.  It closes all file descriptors
  greater than or equal to a given integer.  This function is a GNU extension,
  although it is also present in other systems.

* The posix_spawn_file_actions_addclosefrom_np function has been added,
  enabling posix_spawn and posix_spawnp to close all file descriptors greater
  than or equal to a given integer.  This function is a GNU extension,
  although Solaris also provides a similar function.

* When invoked explicitly, the dynamic linker now uses the kernel to
  execute programs that do not have any dynamic dependency (that is,
  they are statically linked).  This feature is Linux-specific.

* The audit libraries will avoid unnecessary slowdown if it is not required
  PLT tracking (by not implementing the la_pltenter or la_pltexit callbacks).

Deprecated and removed features, and other changes affecting compatibility:

* The function pthread_mutex_consistent_np has been deprecated; programs
  should use the equivalent standard function pthread_mutex_consistent
  instead.

* The function pthread_mutexattr_getrobust_np has been deprecated;
  programs should use the equivalent standard function
  pthread_mutexattr_getrobust instead.

* The function pthread_mutexattr_setrobust_np has been deprecated;
  programs should use the equivalent standard function
  pthread_mutexattr_setrobust instead.

* The function pthread_yield has been deprecated; programs should use
  the equivalent standard function sched_yield instead.

* The function inet_neta declared in <arpa/inet.h> has been deprecated.

* Various rarely-used functions declared in <resolv.h> and
  <arpa/nameser.h> have been deprecated.  Applications are encouraged to
  use dedicated DNS processing libraries if applicable.  For <resolv.h>,
  this affects the functions dn_count_labels, fp_nquery, fp_query,
  fp_resstat, hostalias, loc_aton, loc_ntoa, p_cdname, p_cdnname,
  p_class, p_fqname, p_fqnname, p_option, p_query, p_rcode, p_time,
  p_type, putlong, putshort, res_hostalias, res_isourserver,
  res_nameinquery, res_queriesmatch, res_randomid, sym_ntop, sym_ntos,
  sym_ston.  For <arpa/nameser.h>, the functions ns_datetosecs,
  ns_format_ttl, ns_makecanon, ns_parse_ttl, ns_samedomain, ns_samename,
  ns_sprintrr, ns_sprintrrf, ns_subdomain have been deprecated.

* Various symbols previously defined in libresolv have been moved to libc
  in order to prepare for libresolv moving entirely into libc (see earlier
  entry for merging libraries into libc).  The symbols __dn_comp,
  __dn_expand, __dn_skipname, __res_dnok, __res_hnok, __res_mailok,
  __res_mkquery, __res_nmkquery, __res_nquery, __res_nquerydomain,
  __res_nsearch, __res_nsend, __res_ownok, __res_query, __res_querydomain,
  __res_search, __res_send formerly in libresolv have been renamed and no
  longer have a __ prefix.  They are now available in libc.

* The pthread cancellation handler is now installed with SA_RESTART and
  pthread_cancel will always send the internal SIGCANCEL on a cancellation
  request.  It should not be visible to applications since the cancellation
  handler should either act upon cancellation (if asynchronous cancellation
  is enabled) or ignore the cancellation internal signal.  However there are
  buggy kernel interfaces (for instance some CIFS versions) that could still
  see a spurious EINTR error when cancellation interrupts a blocking syscall.

* Previously, glibc installed its various shared objects under versioned
  file names such as libc-2.33.so.  The ABI sonames (e.g., libc.so.6)
  were provided as symbolic links.  Starting with glibc 2.34, the shared
  objects are installed under their ABI sonames directly, without
  symbolic links.  This increases compatibility with distribution
  package managers that delete removed files late during the package
  upgrade or downgrade process.

* The symbols mallwatch and tr_break are now deprecated and no longer used in
  mtrace.  Similar functionality can be achieved by using conditional
  breakpoints within mtrace functions from within gdb.

* The __morecore and __after_morecore_hook malloc hooks and the default
  implementation __default_morecore have been removed from the API.  Existing
  applications will continue to link against these symbols but the interfaces
  no longer have any effect on malloc.

* Debugging features in malloc such as the MALLOC_CHECK_ environment variable
  (or the glibc.malloc.check tunable), mtrace() and mcheck() have now been
  disabled by default in the main C library.  Users looking to use these
  features now need to preload a new debugging DSO libc_malloc_debug.so to get
  this functionality back.

* The deprecated functions malloc_get_state and malloc_set_state have been
  moved from the core C library into libc_malloc_debug.so.  Legacy applications
  that still use these functions will now need to preload libc_malloc_debug.so
  in their environment using the LD_PRELOAD environment variable.

* The deprecated memory allocation hooks __malloc_hook, __realloc_hook,
  __memalign_hook and __free_hook are now removed from the API.  Compatibility
  symbols are present to support legacy programs but new applications can no
  longer link to these symbols.  These hooks no longer have any effect on glibc
  functionality.  The malloc debugging DSO libc_malloc_debug.so currently
  supports hooks and can be preloaded to get this functionality back for older
  programs.  However this is a transitional measure and may be removed in a
  future release of the GNU C Library.  Users may port away from these hooks by
  writing and preloading their own malloc interposition library.

Changes to build and runtime requirements:

* On Linux, the shm_open, sem_open, and related functions now expect the
  file shared memory file system to be mounted at /dev/shm.  These functions
  no longer search among the system's mount points for a suitable
  replacement if /dev/shm is not available.

Security related changes:

  CVE-2021-27645: The nameserver caching daemon (nscd), when processing
  a request for netgroup lookup, may crash due to a double-free,
  potentially resulting in degraded service or Denial of Service on the
  local system.  Reported by Chris Schanzle.

  CVE-2021-33574: The mq_notify function has a potential use-after-free
  issue when using a notification type of SIGEV_THREAD and a thread
  attribute with a non-default affinity mask.

  CVE-2021-35942: The wordexp function may overflow the positional
  parameter number when processing the expansion resulting in a crash.
  Reported by Philippe Antoine.

The following bugs are resolved with this release:

  [4737] libc: fork is not async-signal-safe
  [5781] math: Slow dbl-64 sin/cos/sincos for special values
  [10353] libc: Methods for deleting all file descriptors greater than
    given integer (closefrom)
  [14185] glob: fnmatch() fails when '*' wildcard is applied on the file
    name containing multi-byte character(s)
  [14469] math: Inaccurate j0f function
  [14470] math: Inaccurate j1f function
  [14471] math: Inaccurate y0f function
  [14472] math: Inaccurate y1f function
  [14744] nptl: kill -32 $pid or kill -33 $pid on a process cancels a
    random thread
  [15271] dynamic-link: dlmopen()ed shared library with LM_ID_NEWLM
    crashes if it fails dlsym() twice
  [15648] nptl: multiple definition of `__lll_lock_wait_private'
  [16063] nptl: Provide a pthread_once variant in libc directly
  [17144] libc: syslog is not thread-safe if NO_SIGPIPE is not defined
  [17145] libc: syslog with LOG_CONS leaks console file descriptor
  [17183] manual: description of ENTRY struct in <search.h> in glibc
    manual is incorrect
  [18435] nptl: pthread_once hangs when init routine throws an exception
  [18524] nptl: Missing calloc error checking in
    __cxa_thread_atexit_impl
  [19329] dynamic-link: dl-tls.c assert failure at concurrent
    pthread_create and dlopen
  [19366] nptl: returning from a thread should disable cancellation
  [19511] nptl: 8MB memory leak in pthread_create in case of failure
    when non-root user changes priority
  [20802] dynamic-link: getauxval NULL pointer dereference after static
    dlopen
  [20813] nptl: pthread_exit is inconsistent between libc and libpthread
  [22057] malloc: malloc_usable_size is broken with mcheck
  [22668] locale: LC_COLLATE: the last character of ellipsis is not
    ordered correctly
  [23323] libc: [RFE] CSU startup hardening.
  [23328] malloc: Remove malloc hooks and ensure related APIs return no
    data.
  [23462] dynamic-link: Static binary with dynamic string tokens ($LIB,
    $PLATFORM, $ORIGIN) crashes
  [23489] libc: "gcc -lmcheck" aborts on free when using posix_memalign
  [23554] nptl: pthread_getattr_np reports wrong stack size with
    MULTI_PAGE_ALIASING
  [24106] libc: Bash interpreter in ldd script is taken from host
  [24773] dynamic-link: dlerror in an secondary namespace does not use
    the right free implementation
  [25036] localedata: Update collation order for Swedish
  [25383] libc: where_is_shmfs/__shm_directory/SHM_GET_NAME may cause
    shm_open to pick wrong directory
  [25680] dynamic-link: ifuncmain9picstatic and ifuncmain9picstatic
    crash in IFUNC resolver due to stack canary (--enable-stack-
    protector=all)
  [26874] build: -Warray-bounds in _IO_wdefault_doallocate
  [26983] math: [x86_64] x86_64 tgamma has too large ULP error
  [27111] dynamic-link: pthread_create and tls access use link_map
    objects that may be concurrently freed by dlclose
  [27132] malloc: memusagestat is linked to system librt, leading to
    undefined symbols on major version upgrade
  [27136] dynamic-link: dtv setup at thread creation may leave an entry
    uninitialized
  [27249] libc: libSegFault.so does not output signal number properly
  [27304] nptl: pthread_cond_destroy does not pass private flag to futex
    system calls
  [27318] dynamic-link: glibc fails to load binaries when built with
    -march=sandybridge:  CPU ISA level is lower than required
  [27343] nss: initgroups() SIGSEGVs when called on a system without
    nsswich.conf (in a chroot)
  [27346] dynamic-link: x86: PTWRITE feature check is missing
  [27389] network: NSS chroot hardening causes regressions in chroot
    deployments
  [27403] dynamic-link: aarch64: tlsdesc htab is not freed on dlclose
  [27444] libc: sysconf reports unsupported option (-1) for
    _SC_LEVEL1_ICACHE_LINESIZE on X86 since v2.33
  [27462] nscd: double-free in nscd (CVE-2021-27645)
  [27468] malloc: aarch64: realloc crash with heap tagging: FAIL:
    malloc/tst-malloc-thread-fail
  [27498] dynamic-link: __dl_iterate_phdr lacks unwinding information
  [27511] libc: S390 memmove assumes Vector Facility when MIE Facility 3
    is present
  [27522] glob: glob, glob64 incorrectly marked as __THROW
  [27555] dynamic-link: Static tests fail with --enable-stack-
    protector=all
  [27559] libc: fstat(AT_FDCWD) succeeds (it shouldn't) and returns
    information for the current directory
  [27577] dynamic-link: elf/ld.so --help doesn't work
  [27605] libc: tunables can't control xsave/xsavec selection in
    dl_runtime_resolve_*
  [27623] libc: powerpc: Missing registers in sc[v] clobbers list
  [27645] libc: [linux] sysconf(_SC_NPROCESSOR...) breaks down on
    containers
  [27646] dynamic-link: Linker error for non-existing NSS symbols (e.g.
    _nss_files_getcanonname_r) from within a dlmopen namespace.
  [27648] libc: FAIL: misc/tst-select
  [27650] stdio: vfscanf returns too early if a match is longer than
    INT_MAX
  [27651] libc: Performance regression after updating to 2.33
  [27655] string: Wrong size calculation in string/test-strnlen.c
  [27706] libc: select fails to update timeout on error
  [27709] libc: arm: FAIL: debug/tst-longjmp_chk2
  [27721] dynamic-link: x86: ld_audit ignores bind now for TLSDESC and
    tries resolving them lazily
  [27744] nptl: Support different libpthread/ld.so load orders in
    libthread_db
  [27749] libc: Data race __run_exit_handlers
  [27761] libc: getconf: Segmentation fault when passing '-vq' as
    argument
  [27832] nss: makedb.c:797:7: error: 'writev' specified size 4294967295
    exceeds maximum object size 2147483647
  [27870] malloc: MALLOC_CHECK_ causes realloc(valid_ptr, TOO_LARGE) to
    not set ENOMEM
  [27872] build: Obsolete configure option --enable-stackguard-
    randomization
  [27873] build: tst-cpu-features-cpuinfo fail when building on AMD cpu
  [27882] localedata: Use U+00AF MACRON in more EBCDIC charsets
  [27892] libc: powerpc: scv ABI error handling fails to check
    IS_ERR_VALUE
  [27896] nptl: mq_notify does not handle separately allocated thread
    attributes (CVE-2021-33574)
  [27901] libc: TEST_STACK_ALIGN doesn't work
  [27902] libc: The x86-64 clone wrapper fails to align child stack
  [27914] nptl: Install SIGSETXID handler with SA_ONSTACK
  [27939] libc: aarch64: clone does not align the stack
  [27968] libc: s390x: clone does not align the stack
  [28011] libc: Wild read in wordexp (parse_param) (CVE-2021-35942)
  [28024] string: s390(31bit): Wrong result of memchr (MEMCHR_Z900_G5)
    with n >= 0x80000000
  [28028] malloc: malloc: tcache shutdown sequence does not work if the
    thread never allocated anything
  [28033] libc: Need to check RTM_ALWAYS_ABORT for RTM
  [28064] string: x86_64:wcslen implementation list has wcsnlen
  [28067] libc: FAIL: posix/tst-spawn5
  [28068] malloc: FAIL: malloc/tst-mallocalign1-mcheck
  [28071] time: clock_gettime, gettimeofday, time lost vDSO acceleration
    on older kernels
  [28075] nis: Out-of-bounds static buffer read in nis_local_domain
  [28089] build: tst-tls20 fails when linker defaults to --as-needed
  [28090] build: elf/tst-cpu-features-cpuinfo-static fails on certain
    AMD64 cpus
  [28091] network: ns_name_skip may return 0 for domain names without
    terminator


Version 2.33

Major new features:

* The dynamic linker accepts the --list-tunables argument which prints
  all the supported tunables.  This option is disable if glibc is
  configured with tunables disabled (--enable-tunables=no).

* The dynamic linker accepts the --argv0 argument and provides opportunity
  to change argv[0] string.

* The dynamic linker loads optimized implementations of shared objects
  from subdirectories under the glibc-hwcaps directory on the library
  search path if the system's capabilities meet the requirements for
  that subdirectory.  Initially supported subdirectories include
  "power9" and "power10" for the powerpc64le-linux-gnu architecture,
  "z13", "z14", "z15" for s390x-linux-gnu, and "x86-64-v2", "x86-64-v3",
  "x86-64-v4" for x86_64-linux-gnu.  In the x86_64-linux-gnu case, the
  subdirectory names correspond to the vendor-independent x86-64
  microarchitecture levels defined in the x86-64 psABI supplement.

* The new --help option of the dynamic linker provides usage and
  information and library search path diagnostics.

* The mallinfo2 function is added to report statistics as per mallinfo,
  but with larger field widths to accurately report values that are
  larger than fit in an integer.

* Add <sys/platform/x86.h> to provide query macros for x86 CPU features.

* Support for the RISC-V ISA running on Linux has been expanded to run on
  32-bit hardware.  This is supported for the following ISA and ABI pairs:

    - rv32imac ilp32
    - rv32imafdc ilp32
    - rv32imafdc ilp32d

  The 32-bit RISC-V port requires at least Linux 5.4, GCC 7.1 and binutils
  2.28.

* A new fortification level _FORTIFY_SOURCE=3 is available.  At this level,
  glibc may use additional checks that may have an additional performance
  overhead.  At present these checks are available only on LLVM 9 and later.
  The latest GCC available at this time (10.2) does not support this level of
  fortification.

Deprecated and removed features, and other changes affecting compatibility:

* The mallinfo function is marked deprecated.  Callers should call
  mallinfo2 instead.

* When dlopen is used in statically linked programs, alternative library
  implementations from HWCAP subdirectories are no longer loaded.
  Instead, the default implementation is used.

* The deprecated <sys/vtimes.h> header and the function vtimes have been
  removed.  To support old binaries, the vtimes function continues to exist
  as a compatibility symbol.  Applications should use the getrlimit or
  prlimit.

* Following a change in the tzdata 2018a release upstream, the zdump
  program is now installed in the /usr/bin subdirectory.  Previously,
  the /usr/sbin subdirectory was used.

* On s390(x), the type float_t is now derived from the macro
  __FLT_EVAL_METHOD__ that is defined by the compiler, instead of being
  hardcoded to double.  This does not affect the ABI of any libraries
  that are part of the GNU C Library, but may affect the ABI of other
  libraries that use this type in their interfaces.  The new definition
  improves consistency with compiler behavior in many scenarios.

* A future version of glibc will stop loading shared objects from the
  "tls" subdirectories on the library search path, the subdirectory that
  corresponds to the AT_PLATFORM system name, and also stop employing
  the legacy AT_HWCAP search mechanism.  Applications should switch to
  the new glibc-hwcaps mechanism instead; if they do not do that, only
  the baseline version (directly from the search path directory) will be
  loaded.

Changes to build and runtime requirements:

* On Linux, the system administrator needs to configure /dev/pts with
  the intended access modes for pseudo-terminals.  glibc no longer
  attemps to adjust permissions of terminal devices.  The previous glibc
  defaults ("tty" group, user read/write and group write) already
  corresponded to what most systems used, so that grantpt did not
  perform any adjustments.

* On Linux, the posix_openpt and getpt functions no longer attempt to
  use legacy (BSD) pseudo-terminals and assume that if /dev/ptmx exists
  (and pseudo-terminals are supported), a devpts file system is mounted
  on /dev/pts.  Current systems already meet these requirements.

* s390x requires GCC 7.1 or newer.  See gcc Bug 98269.

Security related changes:

  CVE-2021-3326: An assertion failure during conversion from the
  ISO-20220-JP-3 character set using the iconv function has been fixed.
  This assertion was triggered by certain valid inputs in which the
  converted output contains a combined sequence of two wide characters
  crossing a buffer boundary.  Reported by Tavis Ormandy.

  CVE-2020-27618: An infinite loop has been fixed in the iconv program when
  invoked with input containing redundant shift sequences in the IBM1364,
  IBM1371, IBM1388, IBM1390, or IBM1399 character sets.

  CVE-2020-29562: An assertion failure has been fixed in the iconv function
  when invoked with UCS4 input containing an invalid character.

  CVE-2019-25013: A buffer overflow has been fixed in the iconv function when
  invoked with EUC-KR input containing invalid multibyte input sequences.

The following bugs are resolved with this release:

  [10635] libc: realpath portability patches
  [16124] dynamic-link: ld.so should allow to change argv[0]
  [17924] malloc: 'free' should not set errno
  [18683] libc: Linux faccessat implementation can incorrectly ignore
    AT_EACCESS
  [22899] libc: Use 64-bit readdir() in generic POSIX getcwd()
  [23091] hurd: missing waitid support
  [23249] libc: Epyc and other current AMD CPUs do not select the
    "haswell" platform subdirectory
  [24080] dynamic-link: Definition of "haswell" platform is inconsistent
    with GCC
  [24202] libc: m68k setjmp() saves incorrect 'a5' register in --enable-
    stack-protector=all
  [24941] libc: Make grantpt usable after multi-threaded fork in more
    cases
  [24970] libc: realpath mishandles EOVERFLOW; stat not needed anyway
  [24973] locale: iconv encounters segmentation fault when converting
    0x00 0xfe in EUC-KR to UTF-8 (CVE-2019-25013)
  [25399] string: undefined reference to `__warn_memset_zero_len' when
    changing gnuc version
  [25859] libc: glibc parser for /sys/devices/system/cpu/online is
    incorrect
  [25938] dynamic-link: ld.so.cache should store meaning of hwcap mask
    bits
  [25971] libc: s390 bits/hwcap.h out of sync with kernel
  [26053] libc: unlockpt fails with ENOTTY for non-ptmx descriptors
  [26100] libc: Race in syslog(3) with regards to tag printing.
  [26124] libc: Export <cpu-features.h>
  [26130] nscd: Inconsistent nscd cache during pruning
  [26203] libc: GLRO(dl_x86_cpu_features) may not be intialized
  [26224] locale: iconv hangs when converting some invalid inputs from
    several IBM character sets (CVE-2020-27618)
  [26341] libc: realpath cyclically call __alloca(path_max) to consume
    too much stack space
  [26343] manual: invalid documented return type for strerrorname_np(),
    strerrordesc_np(), sigdescr_np(), sigabbrev_np()
  [26376] libc: Namespace violation in stdio.h and sys/stat.h if build
    with optimization.
  [26383] locale: bind_textdomain_codeset doesn't accept //TRANSLIT
    anymore
  [26394] time: [2.33 Regression] FAIL: nptl/tst-join14
  [26534] math: libm.so 2.32 SIGILL in pow() due to FMA4 instruction on
    non-FMA4 system
  [26552] dynamic-link: CPU_FEATURE_USABLE_P should be more conservative
  [26553] libc: mtx_init allows type set to "mtx_recursive" only
  [26555] string: strerrorname_np does not return the documented value
  [26592] libc: pointer arithmetic overflows in realpath
  [26600] network: Transaction ID collisions cause slow DNS lookups in
    getaddrinfo
  [26606] libc: [2.33 Regression] pselect is broken on x32
  [26615] libc: powerpc: libc segfaults when LD_PRELOADed with libgcc
  [26620] glob: fnmatch with collating symbols results in segmentation
    fault
  [26625] libc: [2.33 Regression] CET is disabled
  [26636] libc: 32-bit shmctl(IPC_INFO) crashes when shminfo struct is
    at the end of a memory mapping
  [26637] libc: semctl SEM_STAT_ANY fails to pass the buffer specified
    by the caller to the kernel
  [26639] libc: msgctl IPC_INFO and MSG_INFO return garbage
  [26647] build: [-Werror=array-parameter=] due to different
    declarations for __sigsetjmp
  [26648] libc: mkstemp is likely to fail on systems with non-stricly-
    monotonic clocks
  [26649] stdio: printf should handle non-normal x86 long double numbers
    gracefully (CVE-2020-29573)
  [26686] build: -Warray-parameter instances building with GCC 11
  [26687] build: -Warray-bounds instances building with GCC 11
  [26690] stdio: Aliasing violation in __vfscanf_internal
  [26691] nptl: Use a minimum guard size of 64 KiB on aarch64
  [26726] build: GCC warning calling new_composite_name with an array of
    one element
  [26736] libc: FAIL: misc/tst-sysvshm-linux
  [26737] libc: Random FAIL: rt/tst-shm
  [26791] libc: Missing O_CLOEXEC in sysconf.c
  [26798] dynamic-link: aarch64: variant PCS symbols may be incorrectly
    lazy bound
  [26801] nptl: pthread_mutex_clocklock with CLOCK_MONOTONIC can fail on
    PI mutexes
  [26818] string: aarch64: string tests may run ifunc variants that are
    not safe
  [26821] libc: Memory leak test failures on Fedora 33
  [26824] libc: FAIL: elf/tst-cpu-features-supports with recent trunk:
    FSGSBASE/LM/RDRAND check failure
  [26833] time: adjtime() with delta == NULL segfaults on armv7 32bit
    platform
  [26853] libc: aarch64: Missing unwind information in statically linked
    startup code
  [26923] locale: Assertion failure in iconv when converting invalid
    UCS4 (CVE-2020-29562)
  [26926] dynamic-link: aarch64: library dependencies are not bti
    protected
  [26932] libc: sh: Multiple floating point functions defined as stubs
    only since 2.31
  [26964] nptl: pthread_mutex_timedlock returning EAGAIN after futex is
    locked
  [26988] dynamic-link: aarch64: BTI mprotect address is not page
    aligned
  [27002] build: libc_freeres_fn build failure with GCC 11
  [27004] dynamic-link: ld.so is miscompiled by GCC 11
  [27008] dynamic-link: ld.so.cache should have endianness markup
  [27042] libc: [alpha] anonymous union in struct stat confuses
    detection logic
  [27053] libc: Conformance regression in system(3) (and probably also
    pclose(3))
  [27072] dynamic-link: static pie ifunc resolvers run before hwcap is
    setup
  [27077] network: Do not reload /etc/nsswitch.conf from chroot
  [27083] libc: Unsafe unbounded alloca in addmntent
  [27104] dynamic-link: The COMMON_CPUID_INDEX_MAX handshake does not
    work
  [27130] string: "rep movsb" performance issue
  [27150] libc: alpha: wait4() is unavailable in static linking
  [27177] dynamic-link:
    GLIBC_TUNABLES=glibc.cpu.x86_ibt=on:glibc.cpu.x86_shstk=on doesn't
    work
  [27222] dynamic-link: Incorrect sysdeps/x86/tst-cpu-features-cpuinfo.c
  [27237] malloc: deadlock in malloc/tst-malloc-stats-cancellation
  [27256] locale: Assertion failure in ISO-2022-JP-3 gconv module
    related to combining characters (CVE-2021-3326)


Version 2.32

Major new features:

* Unicode 13.0.0 Support: Character encoding, character type info, and
  transliteration tables are all updated to Unicode 13.0.0, using
  generator scripts contributed by Mike FABIAN (Red Hat).

* New locale added: ckb_IQ (Kurdish/Sorani spoken in Iraq)

* Support for Synopsys ARC HS cores (ARCv2 ISA) running Linux has been
  added. This port requires at least binutils-2.32, gcc-8.3 and Linux-5.1.
  Three ABIs are supported:

     - arc-linux-gnu
     - arc-linux-gnuhf
     - arceb-linux-gnu

  The arc* ABIs are little-endian while arceb is big-endian.  All ABIs use
  64-bit time (y2038 safe) and 64-bit file offsets (LFS default).

* The GNU C Library now loads audit modules listed in the DT_AUDIT and
  DT_DEPAUDIT dynamic section entries of the main executable.

* powerpc64le supports IEEE128 long double libm/libc redirects when
  using -mabi=ieeelongdouble to compile C code on supported GCC
  toolchains.  It is recommended to use GCC 8 or newer when testing
  this option.

* To help detect buffer overflows and other out-of-bounds accesses
  several APIs have been annotated with GCC 'access' attribute.  This
  should help GCC 10 issue better warnings.

* On Linux, functions pthread_attr_setsigmask_np and
  pthread_attr_getsigmask_np have been added.  They allow applications
  to specify the signal mask of a thread created with pthread_create.

* The GNU C Library now provides the header file <sys/single_threaded.h>
  which declares the variable __libc_single_threaded.  Applications are
  encouraged to use this variable for single-thread optimizations,
  instead of weak references to symbols historically defined in
  libpthread.

* The functions sigabbrev_np and sigdescr_np have been added.  The
  sigabbrev_np function returns the abbreviated signal name (e.g. "HUP" for
  SIGHUP) while sigdescr_np returns a string describing the signal number
  (e.g "Hangup" for SIGHUP).  Different than strsignal, sigdescr_np does not
  attempt to translate the return description, both functions return
  NULL for an invalid signal number.

  They should be used instead of sys_siglist or sys_sigabbrev and they
  are both thread and async-signal safe.  These functions are GNU extensions.

* The functions strerrorname_np and strerrordesc_np have been added.  The
  strerroname_np function returns error number name (e.g. "EINVAL" for EINVAL)
  while strerrordesc_np returns a string describing the error number
  (e.g "Invalid argument" for EINVAL).  Different than strerror,
  strerrordesc_np does not attempt to translate the return description, both
  functions return NULL for an invalid error number.

  They should be used instead of sys_errlist and sys_nerr, both are
  thread and async-signal safe.  These functions are GNU extensions.

* AArch64 now supports standard branch protection security hardening
  in glibc when it is built with a GCC that is configured with
  --enable-standard-branch-protection (or if -mbranch-protection=standard
  flag is passed when building both GCC target libraries and glibc,
  in either case a custom GCC is needed).  This includes branch target
  identification (BTI) and pointer authentication for return addresses
  (PAC-RET).  They require armv8.5-a and armv8.3-a architecture
  extensions respectively for the protection to be effective,
  otherwise the used instructions are nops.  User code can use PAC-RET
  without libc support, but BTI requires a libc that is built with BTI
  support, otherwise runtime objects linked into user code will not be
  BTI compatible.

Deprecated and removed features, and other changes affecting compatibility:
