This patch simplifies the memory allocation code and uses the sched
routines instead of reimplement it. This still uses a stack
allocation buffer, so it can be used on malloc initialization code.
Linux currently supports at maximum of 4096 cpus for most architectures:
$ find -iname Kconfig | xargs git grep -A10 -w NR_CPUS | grep -w range
arch/alpha/Kconfig- range 2 32
arch/arc/Kconfig- range 2 4096
arch/arm/Kconfig- range 2 16 if DEBUG_KMAP_LOCAL
arch/arm/Kconfig- range 2 32 if !DEBUG_KMAP_LOCAL
arch/arm64/Kconfig- range 2 4096
arch/csky/Kconfig- range 2 32
arch/hexagon/Kconfig- range 2 6 if SMP
arch/ia64/Kconfig- range 2 4096
arch/mips/Kconfig- range 2 256
arch/openrisc/Kconfig- range 2 32
arch/parisc/Kconfig- range 2 32
arch/riscv/Kconfig- range 2 32
arch/s390/Kconfig- range 2 512
arch/sh/Kconfig- range 2 32
arch/sparc/Kconfig- range 2 32 if SPARC32
arch/sparc/Kconfig- range 2 4096 if SPARC64
arch/um/Kconfig- range 1 1
arch/x86/Kconfig-# [NR_CPUS_RANGE_BEGIN ... NR_CPUS_RANGE_END] range.
arch/x86/Kconfig- range NR_CPUS_RANGE_BEGIN NR_CPUS_RANGE_END
arch/xtensa/Kconfig- range 2 32
With x86 supporting 8192:
arch/x86/Kconfig
976 config NR_CPUS_RANGE_END
977 int
978 depends on X86_64
979 default 8192 if SMP && CPUMASK_OFFSTACK
980 default 512 if SMP && !CPUMASK_OFFSTACK
981 default 1 if !SMP
So using a maximum of 32k cpu should cover all cases (and I would
expect once we start to have many more CPUs that Linux would provide
a more straightforward way to query for such information).
A test is added to check if sched_getaffinity can successfully return
with large buffers.
This is an internal function meant to return the number of avaliable
processor where the process can scheduled, different than the
__get_nprocs which returns a the system available online CPU.
The Linux implementation currently only calls __get_nprocs(), which
in tuns calls sched_getaffinity.
Florian Weimer [Fri, 1 Oct 2021 16:16:41 +0000 (18:16 +0200)]
nptl: pthread_kill must send signals to a specific thread [BZ #28407]
The choice between the kill vs tgkill system calls is not just about
the TID reuse race, but also about whether the signal is sent to the
whole process (and any thread in it) or to a specific thread.
This was caught by the openposix test suite:
LTP: openposix test suite - FAIL: SIGUSR1 is member of new thread pendingset.
<https://gitlab.com/cki-project/kernel-tests/-/issues/764>
Reviewed-by: Carlos O'Donell <carlos@redhat.com> Tested-by: Carlos O'Donell <carlos@redhat.com>
(cherry picked from commit eae81d70574e923ce3c59078b8df857ae192efa6)
Florian Weimer [Fri, 1 Oct 2021 16:16:41 +0000 (18:16 +0200)]
support: Add check for TID zero in support_wait_for_thread_exit
Some kernel versions (observed with kernel 5.14 and earlier) can list
"0" entries in /proc/self/task. This happens when a thread exits
while the task list is being constructed. Treat this entry as not
present, like the proposed kernel patch does:
[PATCH] procfs: Do not list TID 0 in /proc/<pid>/task
<https://lore.kernel.org/all/8735pn5dx7.fsf@oldenburg.str.redhat.com/>
Reviewed-by: Carlos O'Donell <carlos@redhat.com> Tested-by: Carlos O'Donell <carlos@redhat.com>
(cherry picked from commit 176c88f5214d8107d330971cbbfbbba5186a111f)
nptl: Avoid setxid deadlock with blocked signals in thread exit [BZ #28361]
As part of the fix for bug 12889, signals are blocked during
thread exit, so that application code cannot run on the thread that
is about to exit. This would cause problems if the application
expected signals to be delivered after the signal handler revealed
the thread to still exist, despite pthread_kill can no longer be used
to send signals to it. However, glibc internally uses the SIGSETXID
signal in a way that is incompatible with signal blocking, due to the
way the setxid handshake delays thread exit until the setxid operation
has completed. With a blocked SIGSETXID, the handshake can never
complete, causing a deadlock.
As a band-aid, restore the previous handshake protocol by not blocking
SIGSETXID during thread exit.
The new test sysdeps/pthread/tst-pthread-setuid-loop.c is based on
a downstream test by Martin Osvald.
Reviewed-by: Carlos O'Donell <carlos@redhat.com> Tested-by: Carlos O'Donell <carlos@redhat.com>
(cherry picked from commit 2849e2f53311b66853cb5159b64cba2bddbfb854)
It returns a range of file descriptor referring to the '/dev/null'
pathname. The function takes care of restarting the open range
if a file descriptor is found within the specified range and
also increases RLIMIT_NOFILE if required.
nptl: Fix type of pthread_mutexattr_getrobust_np, pthread_mutexattr_setrobust_np (bug 28036)
Reviewed-by: Carlos O'Donell <carlos@redhat.com> Tested-by: Carlos O'Donell <carlos@redhat.com>
(cherry picked from commit f3e664563361dc17530113b3205998d1f19dc4d9)
nptl: pthread_kill needs to return ESRCH for old programs (bug 19193)
The fix for bug 19193 breaks some old applications which appear
to use pthread_kill to probe if a thread is still running, something
that is not supported by POSIX.
posix: Fix attribute access mode on getcwd [BZ #27476]
There is a GNU extension that allows to call getcwd(NULL, >0). It is
described in the documentation, but also directly in the unistd.h
header, just above the declaration.
Therefore the attribute access mode added in commit 06febd8c6705
is not correct. Drop it.
Joseph Myers [Tue, 14 Sep 2021 14:19:24 +0000 (14:19 +0000)]
Add MADV_POPULATE_READ and MADV_POPULATE_WRITE from Linux 5.14 to bits/mman-linux.h
Linux 5.14 adds constants MADV_POPULATE_READ and MADV_POPULATE_WRITE
(with the same values on all architectures). Add these to glibc's
bits/mman-linux.h.
Joseph Myers [Tue, 14 Sep 2021 13:51:58 +0000 (13:51 +0000)]
Update kernel version to 5.14 in tst-mman-consts.py
This patch updates the kernel version in the test tst-mman-consts.py
to 5.14. (There are no new MAP_* constants covered by this test in
5.14 that need any other header changes.)
Joseph Myers [Wed, 8 Sep 2021 12:42:06 +0000 (12:42 +0000)]
Update syscall lists for Linux 5.14
Linux 5.14 has two new syscalls, memfd_secret (on some architectures
only) and quotactl_fd. Update syscall-names.list and regenerate the
arch-syscall.h headers with build-many-glibcs.py update-syscalls.
Fix failing nss/tst-nss-files-hosts-long with local resolver
When a local resolver like unbound is listening on the IPv4 loopback
address 127.0.0.1, the nss/tst-nss-files-hosts-long test fails. This is
due to:
- the default resolver in the absence of resolv.conf being 127.0.0.1
- the default DNS NSS database configuration in the absence of
nsswitch.conf being 'hosts: dns [!UNAVAIL=return] file'
This causes the requests for 'test4' and 'test6' to first be sent to the
local resolver, which responds with NXDOMAIN in the likely case those
records do no exist. In turn that causes the access to /etc/hosts to be
skipped, which is the purpose of that test.
Fix that by providing a simple nsswitch.conf file forcing access to
/etc/hosts for that test. I have tested that the only changed result in
the testsuite is that test.
iconvconfig: Fix behaviour with --prefix [BZ #28199]
The consolidation of configuration parsing broke behaviour with
--prefix, where the prefix bled into the modules cache. Accept a
prefix which, when non-NULL, is prepended to the path when looking for
configuration files but only the original directory is added to the
modules cache.
This has no effect on the codegen of gconv_conf since it passes NULL.
Reported-by: Patrick McCarty <patrick.mccarty@intel.com> Reported-by: Michael Hudson-Doyle <michael.hudson@canonical.com> Reviewed-by: Andreas Schwab <schwab@linux-m68k.org>
(cherry picked from commit 43cea6d5652b6b9e61ac6ecc69419c909b504f47)
nptl: Fix race between pthread_kill and thread exit (bug 12889)
A new thread exit lock and flag are introduced. They are used to
detect that the thread is about to exit or has exited in
__pthread_kill_internal, and the signal is not sent in this case.
The test sysdeps/pthread/tst-pthread_cancel-select-loop.c is derived
from a downstream test originally written by Marek Polacek.
nptl: pthread_kill, pthread_cancel should not fail after exit (bug 19193)
This closes one remaining race condition related to bug 12889: if
the thread already exited on the kernel side, returning ESRCH
is not correct because that error is reserved for the thread IDs
(pthread_t values) whose lifetime has ended. In case of a
kernel-side exit and a valid thread ID, no signal needs to be sent
and cancellation does not have an effect, so just return 0.
sysdeps/pthread/tst-kill4.c triggers undefined behavior and is
removed with this commit.
Jiaxun Yang [Tue, 7 Sep 2021 05:31:42 +0000 (13:31 +0800)]
MIPS: Setup errno for {f,l,}xstat
{f,l,}xstat stub for MIPS is using INTERNAL_SYSCALL
to do xstat syscall for glibc ver, However it leaves
errno untouched and thus giving bad errno output.
Setup errno properly when syscall returns non-zero.
Signed-off-by: Jiaxun Yang <jiaxun.yang@flygoat.com> Reviewed-by: Adhemerval Zanella <adhemerval.zanella@linaro.org>
(cherry picked from commit 66016ec8aeefd40e016d7040d966484c764b0e9c)
Nikita Popov [Thu, 12 Aug 2021 10:39:50 +0000 (16:09 +0530)]
librt: add test (bug 28213)
This test implements following logic:
1) Create POSIX message queue.
Register a notification with mq_notify (using NULL attributes).
Then immediately unregister the notification with mq_notify.
Helper thread in a vulnerable version of glibc
should cause NULL pointer dereference after these steps.
2) Once again, register the same notification.
Try to send a dummy message.
Test is considered successfulif the dummy message
is successfully received by the callback function.
Nikita Popov [Mon, 9 Aug 2021 14:47:34 +0000 (20:17 +0530)]
librt: fix NULL pointer dereference (bug 28213)
Helper thread frees copied attribute on NOTIFY_REMOVED message
received from the OS kernel. Unfortunately, it fails to check whether
copied attribute actually exists (data.attr != NULL). This worked
earlier because free() checks passed pointer before actually
attempting to release corresponding memory. But
__pthread_attr_destroy assumes pointer is not NULL.
So passing NULL pointer to __pthread_attr_destroy will result in
segmentation fault. This scenario is possible if
notification->sigev_notify_attributes == NULL (which means default
thread attributes should be used).
Florian Weimer [Fri, 6 Aug 2021 07:51:38 +0000 (09:51 +0200)]
Linux: Fix fcntl, ioctl, prctl redirects for _TIME_BITS=64 (bug 28182)
__REDIRECT and __THROW are not compatible with C++ due to the ordering of the
__asm__ alias and the throw specifier. __REDIRECT_NTH has to be used
instead.
x86-64: Avoid rep movsb with short distance [BZ #27130]
introduced some regressions on Intel processors without Fast Short REP
MOV (FSRM). Add Avoid_Short_Distance_REP_MOVSB to avoid rep movsb with
short distance only on Intel processors with FSRM. bench-memmove-large
on Skylake server shows that cycles of __memmove_evex_unaligned_erms
improves for the following data size:
tests: use xmalloc to allocate implementation array
The benchmark and tests must fail in case of allocation failure in the
implementation array. Also annotate the x* allocators in support.h so
that the compiler has more information about them.
Tell the compiler that xmalloc family of allocators always return
non-NULL. xrealloc in locale/programs also always returns non-NULL,
but that conflicts with default realloc behaviour and that of xrealloc
in libsupport, so keep it as is for now and resolve the differences
later.
mcheck and malloc-check no longer work with static binaries, so drop
those tests.
Reported-by: Samuel Thibault <samuel.thibault@gnu.org> Tested-by: Samuel Thibault <samuel.thibault@gnu.org> Reviewed-by: Samuel Thibault <samuel.thibault@ens-lyon.org>
manual: Document unsupported cases for interposition
These functions call the core allocator functions (realloc and malloc
respectively) and are hence guaranteed to allocate memory using the
correct functions when multiple allocators are interposed. Having
these functions interposed in one allocator and not another may result
in confusion, hence discourage interposing them altogether.
H.J. Lu [Sat, 5 Jun 2021 13:42:20 +0000 (06:42 -0700)]
x86: Install <bits/platform/x86.h> [BZ #27958]
1. Install <bits/platform/x86.h> for <sys/platform/x86.h> which includes
<bits/platform/x86.h>.
2. Rename HAS_CPU_FEATURE to CPU_FEATURE_PRESENT which checks if the
processor has the feature.
3. Rename CPU_FEATURE_USABLE to CPU_FEATURE_ACTIVE which checks if the
feature is active. There may be other preconditions, like sufficient
stack space or further setup for AMX, which must be satisfied before the
feature can be used.
Samuel Thibault [Thu, 22 Jul 2021 18:29:57 +0000 (18:29 +0000)]
hurd: Fix glob lstat compatibility
84f7ce84474c ("posix: Add glob64 with 64-bit time_t support") replaced
GLOB_NO_LSTAT with defining GLOB_LSTAT and GLOB_LSTAT64, but the posix
and gnu versions of the change were missing in the commit.
Make malloc hooks symbols compat-only so that new applications cannot
link against them and remove the declarations from the API. Also
remove the unused malloc-hooks.h.
Finally, mark all symbols in libc_malloc_debug.so as compat so that
the library cannot be linked against.
Add a note about the deprecation in NEWS.
Reviewed-by: Carlos O'Donell <carlos@redhat.com> Tested-by: Carlos O'Donell <carlos@redhat.com>
These deprecated functions are only safe to call from
__malloc_initialize_hook and as a result, are not useful in the
general case. Move the implementations to libc_malloc_debug so that
existing binaries that need it will now have to preload the debug DSO
to work correctly.
This also allows simplification of the core malloc implementation by
dropping all the undumping support code that was added to make
malloc_set_state work.
One known breakage is that of ancient emacs binaries that depend on
this. They will now crash when running with this libc. With
LD_BIND_NOW=1, it will terminate immediately because of not being able
to find malloc_set_state but with lazy binding it will crash in
unpredictable ways. It will need a preloaded libc_malloc_debug.so so
that its initialization hook is executed to allow its malloc
implementation to work properly.
Reviewed-by: Carlos O'Donell <carlos@redhat.com> Tested-by: Carlos O'Donell <carlos@redhat.com>
The malloc-check debugging feature is tightly integrated into glibc
malloc, so thanks to an idea from Florian Weimer, much of the malloc
implementation has been moved into libc_malloc_debug.so to support
malloc-check. Due to this, glibc malloc and malloc-check can no
longer work together; they use altogether different (but identical)
structures for heap management. This should not make a difference
though since the malloc check hook is not disabled anywhere.
malloc_set_state does, but it does so early enough that it shouldn't
cause any problems.
The malloc check tunable is now in the debug DSO and has no effect
when the DSO is not preloaded.
Reviewed-by: Carlos O'Donell <carlos@redhat.com> Tested-by: Carlos O'Donell <carlos@redhat.com>
Wean mtrace away from the malloc hooks and move them into the debug
DSO. Split the API away from the implementation so that we can add
the API to libc.so as well as libc_malloc_debug.so, with the libc
implementations being empty.
Update localplt data since memalign no longer has any callers after
this change.
Reviewed-by: Carlos O'Donell <carlos@redhat.com> Tested-by: Carlos O'Donell <carlos@redhat.com>
Now that mcheck no longer needs to check __malloc_initialized (and no
other third party hook can since the symbol is not exported), make the
variable boolean and static so that it is used strictly within malloc.
Reviewed-by: Carlos O'Donell <carlos@redhat.com> Tested-by: Carlos O'Donell <carlos@redhat.com>
Split the mcheck implementation into the debugging hooks and API so
that the API can be replicated in libc and libc_malloc_debug.so. The
libc APIs always result in failure.
The mcheck implementation has also been moved entirely into
libc_malloc_debug.so and with it, all of the hook initialization code
can now be moved into the debug library. Now the initialization can
be done independently of libc internals.
With this patch, libc_malloc_debug.so can no longer be used with older
libcs, which is not its goal anyway. tst-vfork3 breaks due to this
since it spawns shell scripts, which in turn execute using the system
glibc. Move the test to tests-container so that only the built glibc
is used.
This move also fixes bugs in the mcheck version of memalign and
realloc, thus allowing removal of the tests from tests-mcheck
exclusion list.
Reviewed-by: Carlos O'Donell <carlos@redhat.com> Tested-by: Carlos O'Donell <carlos@redhat.com>
Remove all malloc hook uses from core malloc functions and move it
into a new library libc_malloc_debug.so. With this, the hooks now no
longer have any effect on the core library.
libc_malloc_debug.so is a malloc interposer that needs to be preloaded
to get hooks functionality back so that the debugging features that
depend on the hooks, i.e. malloc-check, mcheck and mtrace work again.
Without the preloaded DSO these debugging features will be nops.
These features will be ported away from hooks in subsequent patches.
Similarly, legacy applications that need hooks functionality need to
preload libc_malloc_debug.so.
The symbols exported by libc_malloc_debug.so are maintained at exactly
the same version as libc.so.
Finally, static binaries will no longer be able to use malloc
debugging features since they cannot preload the debugging DSO.
Reviewed-by: Carlos O'Donell <carlos@redhat.com> Tested-by: Carlos O'Donell <carlos@redhat.com>
Make the __morecore and __default_morecore symbols compat-only and
remove their declarations from the API. Also, include morecore.c
directly into malloc.c; this should ideally get merged into malloc in
a future cleanup.
Reviewed-by: Carlos O'Donell <carlos@redhat.com> Tested-by: Carlos O'Donell <carlos@redhat.com>
Remove __after_morecore_hook from the API and finalize the symbol so
that it can no longer be used in new applications. Old applications
using __after_morecore_hook will find that their hook is no longer
called.
Reviewed-by: Carlos O'Donell <carlos@redhat.com> Tested-by: Carlos O'Donell <carlos@redhat.com>
Make mcheck tests conditional on GLIBC_2.23 or earlier
Targets with base versions of 2.24 or later won't have
__malloc_initialize_hook because of which the tests will essentially
be the same as the regular malloc tests. Avoid running them instead
and save time.
Reviewed-by: Carlos O'Donell <carlos@redhat.com> Tested-by: Carlos O'Donell <carlos@redhat.com>
ARC: fp: (micro)optimize FPU_STATUS read by eliding FWE bit clearing
Any FPU_STATUS write needs setting the FWE bit (31) whcih just provides
a "control signal" to enable explicit write (vs. the side-effect of FPU
instructions). However this bit is RAZ and write-only, thus effectively
never stored in FPU_STATUS register. Thus when reading the register
there is no need to clear it. This shaves off a BCLR instruction from
the fe*exceptino family of functions and while no big deal still makes
sense to do.
This came up when debugging a race in math/test-fenv-tls [1]
elf: Fix tst-cpu-features-cpuinfo on some AMD systems (BZ #28090)
The SSBD feature is implemented in 2 different ways on AMD processors:
newer systems (Zen3) provides AMD_SSBD (function 8000_0008, EBX[24]),
while older system provides AMD_VIRT_SSBD (function 8000_0008, EBX[25]).
However for AMD_VIRT_SSBD, kernel shows both 'ssdb' and 'virt_ssdb' on
/proc/cpuinfo; while for AMD_SSBD only 'ssdb' is provided.
This now check is AMD_SSBD is set to check for 'ssbd', otherwise check
if AMD_VIRT_SSDB is set to check for 'virt_ssbd'.
nss: Directly load nss_dns, without going through dlsym/dlopen
This partially fixes static-only NSS support (bug 27959): The dns
module no longer needs dlopen. Support for disabling dlopen altogher
remains to be added.
This commit introduces module_load_builtin into nss/nss_module.c, which
handles the common parts of loading the built-in nss_files and nss_dns
modules.
Reviewed-by: Carlos O'Donell <carlos@redhat.com> Tested-by: Carlos O'Donell <carlos@redhat.com>
This switches to public symbols without __ prefixes, due to improved
namespace management in glibc.
The script was used with --no-new-version to move the symbols
__res_nquery, __res_nquerydomain, __res_nsearch, __res_query,
__res_querydomain, __res_search, res_query, res_querydomain,
res_search. The public symbols res_nquery, res_nquerydomain,
res_nsearch, res_ownok, res_query, res_querydomain, res_search
were added with make update-all-abi.
Reviewed-by: Carlos O'Donell <carlos@redhat.com> Tested-by: Carlos O'Donell <carlos@redhat.com>
This switches to public symbols without __ prefixes, due to improved
namespace management in glibc.
The symbols res_mkquery, __res_mkquery, __res_nmkquery were
moved with the script (using --no-new-version).
res_mkquery@@GLIBC_2.34, res_nmkquery@@GLIBC_2.34 were added using
make update-all-abi.
Reviewed-by: Carlos O'Donell <carlos@redhat.com> Tested-by: Carlos O'Donell <carlos@redhat.com>
Switch to public symbols without __ prefix (due to improved
namespace management).
__res_send, __res_nsend were moved using the script (with
--no-new-version). res_send@@GLIBC_2.34 and res_nsend@@GLIBC_2.34
were added using make update-all-abi.
resolv: Move res_nameinquery to its own file and into libc
And reformat to GNU style.
This deprecated function is used in the implementation of the stub
resolver (for now). Keep the public symbol in libresolv for now
(so that no new symbol version is needed), and add a forwarder to
libresolv.
Reviewed-by: Carlos O'Donell <carlos@redhat.com> Tested-by: Carlos O'Donell <carlos@redhat.com>
resolv: Move ns_samename into its own file, and into libc
But only as an internal symbol, __libc_ns_samename. The libresolv
ABI is preserved. This is because the function is deprecated, and
it does not make sense to add new symbol versions for deprecated
functions.
Also reformat the implementation to GNU style.
Reviewed-by: Carlos O'Donell <carlos@redhat.com> Tested-by: Carlos O'Donell <carlos@redhat.com>
resolv: Move ns_makecanon into its own file, and into libc
But only as an internal symbol, __libc_ns_makecanon. The libresolv
ABI is preserved. This is because the function is deprecated, and
it does not make sense to add new symbol versions for deprecated
functions.
Also reformat the implementation to GNU style.
Reviewed-by: Carlos O'Donell <carlos@redhat.com> Tested-by: Carlos O'Donell <carlos@redhat.com>
resolv: Move __res_get_nsaddr to its own file and into libc
Eliminate the use of the EXT macro from it because it does not
add clarity. The function was added to res_send.c in 2015, and
the copyright year reflects that.
Reviewed-by: Carlos O'Donell <carlos@redhat.com> Tested-by: Carlos O'Donell <carlos@redhat.com>
resolv: Rename res_comp.c to res-name-checking.c and move into libc
This reflects what the remaining functions in the file do.
The __res_dnok, __res_hnok, __res_mailok, __res_ownok were moved
with the script, using --no-new-version, and turned into compat
symbols. __libc_res_dnok@@GLIBC_PRIVATE and
__libc_res_hnok@@GLIBC_PRIVATE are added for internal use, to avoid
accidentally binding to compatibility symbols. The new public
symbols res_dnok, res_hnok, res_mailok, res_ownok were added using
make update-all-abi.
Reviewed-by: Carlos O'Donell <carlos@redhat.com> Tested-by: Carlos O'Donell <carlos@redhat.com>
resolv: Move dn_skipname to its own file and into libc
And reformat it to GNU style.
dn_skipname is used outside glibc, so do not deprecate it,
and export it as dn_skipname (not __dn_skipname). Due to internal
users, provide a __libc_dn_skipname alias, and keep __dn_skipname
as a pure compatibility symbol.
__dn_skipname@GLIBC_2.0 was moved using the script, and
dn_skipname@@GLIBC_2.34 was added using make update-all-abi.
Reviewed-by: Carlos O'Donell <carlos@redhat.com> Tested-by: Carlos O'Donell <carlos@redhat.com>
resolv: Move dn_comp to its own file and into libc
And reformat it to GNU style.
dn_comp is used in various programs, so keep it as a non-deprecated
symbol. Switch to dn_comp (not __dn_comp) for the ABI name. There
are no internal users, so interposition is not a problem.
The __dn_comp symbol was moved with scripts/move-symbol-to-libc.py
--no-new-version. dn_comp@@GLIBC_2.34 was added with
make update-all-abi.
Reviewed-by: Carlos O'Donell <carlos@redhat.com> Tested-by: Carlos O'Donell <carlos@redhat.com>
resolv: Move dn_expand to its own file and into libc
And reformat to GNU style.
This switches back to the dn_expand name for the ABI symbol and turns
__dn_expand into a compatibility symbol. With the improved namespace
management in current glibc, it is no longer necessary to use a
private namespace symbol. To avoid old code binding to a
GLIBC_PRIVATE symbol by accident, use __libc_dn_expand for the
internal symbol name.
The symbols dn_expand, __dnexpand were moved using
scripts/move-symbol-to-libc.py, followed by an adjustment to make
dn_expand the only GLIBC_2.34 symbol.
Reviewed-by: Carlos O'Donell <carlos@redhat.com> Tested-by: Carlos O'Donell <carlos@redhat.com>