#4415: glibc-2.29
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Reporter: bdubbs | Owner: lfs-book
Type: task | Status: new
Priority: normal | Milestone: 8.4
Component: Book | Version: SVN
Severity: normal | Keywords:
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New minor version.
Major new features:
* The getcpu wrapper function has been added, which returns the currently
used CPU and NUMA node. This function is Linux-specific.
* A new convenience target has been added for distribution maintainers
to build and install all locales as directories with files. The new
target is run by issuing the following command in your build tree:
'make localedata/install-locale-files', with an optional DESTDIR
to set the install root if you wish to install into a non-default
configured location.
* Optimized generic exp, exp2, log, log2, pow, sinf, cosf, sincosf and
tanf.
* The reallocarray function is now declared under _DEFAULT_SOURCE, not
just
for _GNU_SOURCE, to match BSD environments.
* For powercp64le ABI, Transactional Lock Elision is now enabled iff
kernel
indicates that it will abort the transaction prior to entering the
kernel
(PPC_FEATURE2_HTM_NOSC on hwcap2). On older kernels the transaction is
suspended, and this caused some undefined side-effects issues by
aborting
transactions manually. Glibc avoided it by abort transactions manually
on
each syscall, but it lead to performance issues on newer kernels where
the
HTM state is saved and restore lazily (the state being saved even when
the
process actually does not use HTM).
* The functions posix_spawn_file_actions_addchdir_np and
posix_spawn_file_actions_addfchdir_np have been added, enabling
posix_spawn and posix_spawnp to run the new process in a different
directory. These functions are GNU extensions. The function
posix_spawn_file_actions_addchdir_np is similar to the Solaris function
of the same name.
* The popen and system do not run atfork handlers anymore (BZ#17490).
Although it is a possible POSIX violation, the POSIX rationale in
pthread_atfork documentation regarding atfork handlers is to handle
inconsistent mutex state after a fork call in a multi-threaded process.
In both popen and system there is no direct access to user-defined
mutexes.
* Support for the C-SKY ABIV2 running on Linux has been added. This port
requires at least binutils-2.32, gcc-9.0, and linux-4.20. Two ABIs are
supported:
- C-SKY ABIV2 soft-float little-endian
- C-SKY ABIV2 hard-float little-endian
* strftime's default formatting of a locale's alternative year (%Ey)
has been changed to zero-pad the year to a minimum of two digits,
like "%y". This improves the display of Japanese era years during
the first nine years of a new era, and is expected to be harmless
for all other locales (only Japanese locales regularly have
alternative year numbers less than 10). Zero-padding can be
overridden with the '_' or '-' flags (which are GNU extensions).
* As a GNU extension, the '_' and '-' flags can now be applied to
"%EY" to control how the year number is formatted; they have the
same effect that they would on "%Ey".
Deprecated and removed features, and other changes affecting
compatibility:
* The glibc.tune tunable namespace has been renamed to glibc.cpu and the
tunable glibc.tune.cpu has been renamed to glibc.cpu.name.
* The type of the pr_uid and pr_gid members of struct elf_prpsinfo,
defined
in <sys/procfs.h>, has been corrected to match the type actually used by
the Linux kernel. This affects the size and layout of that structure on
MicroBlaze, MIPS (n64 ABI only), Nios II and RISC-V.
* For the MIPS n32 ABI, the type of the pr_sigpend and pr_sighold members
of
struct elf_prstatus, and the pr_flag member of struct elf_prpsinfo,
defined in <sys/procfs.h>, has been corrected to match the type actually
used by the Linux kernel. This affects the size and layout of those
structures.
* An archaic GNU extension to scanf, under which '%as', '%aS', and
'%a[...]'
meant to scan a string and allocate space for it with malloc, is now
restricted to programs compiled in C89 or C++98 mode with _GNU_SOURCE
defined. This extension conflicts with C99's use of '%a' to scan a
hexadecimal floating-point number, which is now available to programs
compiled as C99 or C++11 or higher, regardless of _GNU_SOURCE.
POSIX.1-2008 includes the feature of allocating a buffer for string
input
with malloc, using the modifier letter 'm' instead. Programs using
'%as', '%aS', or '%a[...]' with the old GNU meaning should change to
'%ms', '%mS', or '%m[...]' respectively. Programs that wish to use the
C99 '%a' no longer need to avoid _GNU_SOURCE.
GCC's -Wformat warnings can detect most uses of this extension, as long
as all functions that call vscanf, vfscanf, or vsscanf are annotated
with
__attribute__ ((format (scanf, ...))).
Changes to build and runtime requirements:
* Python 3.4 or later is required to build the GNU C Library.
* On most architectures, GCC 5 or later is required to build the GNU C
Library. (On powerpc64le, GCC 6.2 or later is still required, as
before.)
Older GCC versions and non-GNU compilers are still supported when
compiling programs that use the GNU C Library.
Security related changes:
CVE-2018-19591: A file descriptor leak in if_nametoindex can lead to a
denial of service due to resource exhaustion when processing getaddrinfo
calls with crafted host names. Reported by Guido Vranken.
CVE-2019-6488: On x32, the size_t parameter may be passed in the lower
32 bits of a 64-bit register with with non-zero upper 32 bit. When it
happened, accessing the 32-bit size_t value as the full 64-bit register
in the assembly string/memory functions would cause a buffer overflow.
Reported by H.J. Lu.
CVE-2016-10739: The getaddrinfo function could successfully parse IPv4
addresses with arbitrary trailing characters, potentially leading to
data
or command injection issues in applications.
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