This code manages the mappings of the available databases in NSS
(i.e. passwd, hosts, netgroup, etc) with the actions that should
be taken to do a query on those databases.
This is the main API between query functions scattered throughout
glibc and the underlying code (actions, modules, etc).
Reviewed-by: Siddhesh Poyarekar <siddhesh@sourceware.org>
nss_action manages a set of lists of actions; these are the portions
of the lines in nsswitch.conf to the right of the colons, like
"dns [!UNAVAIL=return] files". Each permutation of actions and
conditionals is cached for reuse, which limits memory growth, and
refers to the static list of modules managed by nss_modules.
Reviewed-by: Siddhesh Poyarekar <siddhesh@sourceware.org>
This provides the struct nss_module type, which combines the old
struct service_library type with the known_function tree, by
statically allocating space for all function pointers.
struct nss_module is fairly large (536 bytes), but it will be
shared across NSS databases. The old known_function handling
had non-some per-function overhead (at least 32 bytes per looked-up
function, but more for long function anmes), so overall, this is not
too bad. Resolving all functions at load time simplifies locking,
and the repeated lookups should be fast because the caches are hot
at this point.
Reviewed-by: Siddhesh Poyarekar <siddhesh@sourceware.org>
Check HAS_CPU_FEATURE instead of CPU_FEATURE_USABLE for FSGSBASE, IBT,
LM, SHSTK and XSAVES since FSGSBASE requires kernel support, IBT/SHSTK/LM
require OS support and XSAVES is supervisor-mode only.
Following macros: lll_futex_timed_lock_pi, lll_futex_clock_wait_bitset,
lll_futex_wait_requeue_pi, lll_futex_timed_wait_requeue_pi are not
used anymore so are eligible for removal.
Build tests:
./src/scripts/build-many-glibcs.py glibcs
Reviewed-by: Adhemerval Zanella <adhemerval.zanella@linaro.org>
Reviewed-by: Alistair Francis <alistair.francis@wdc.com>
After gai_suspend and aio_suspend conversion to support 64 bit time and
hence rewriting the code to use only absolute variants of futex wait
functions (i.e. __futex_abstimed_wait64 and __futex_abstimed_wait_cancelable64)
futex_reltimed_wait{_cancelable} are not needed anymore and can be removed.
Build tests:
./src/scripts/build-many-glibcs.py glibcs
Reviewed-by: Adhemerval Zanella <adhemerval.zanella@linaro.org>
Reviewed-by: Alistair Francis <alistair.francis@wdc.com>
This change uses (in gai_misc.h):
- __futex_abstimed_wait64 (instead of futex_reltimed_wait)
- __futex_abstimed_wait_cancellable64
(instead of futex_reltimed_wait_cancellable)
from ./sysdeps/nptl/futex-helpers.h
The gai_suspend() accepts relative timeout, which then is converted to
absolute one.
The i686-gnu port (HURD) do not define DONT_NEED_GAI_MISC_COND and as it
doesn't (yet) support 64 bit time it uses not converted
pthread_cond_timedwait().
The __gai_suspend() is supposed to be run on ports with __TIMESIZE !=64 and
__WORDSIZE==32. It internally utilizes __gai_suspend_time64() and hence the
conversion from 32 bit struct timespec to 64 bit one is required.
For ports supporting 64 bit time the __gai_suspend_time64() will be used
either via alias (to __gai_suspend when __TIMESIZE==64) or redirection
(when -D_TIME_BITS=64 is passed).
Build tests:
./src/scripts/build-many-glibcs.py glibcs
Reviewed-by: Adhemerval Zanella <adhemerval.zanella@linaro.org>
Reviewed-by: Alistair Francis <alistair.francis@wdc.com>
The __gai_suspend_time64, which supports 64 bit time on ports with
__WORDSIZE == 32 && __TIMESIZE != 64, shall be exported from libanl
(the same library from which original gai_suspend is exported).
Up till now there were no defines for this library. This commit adds
them.
This recognizes the DL_CACHE_HWCAP_EXTENSION flag in cache entries,
and picks the supported cache entry with the highest priority.
The elf/tst-glibc-hwcaps-prepend-cache test documents a non-desired
aspect of the current cache implementation: If the cache selects a DSO
that does not exist on disk, _dl_map_object falls back to open_path,
which may or may not find an alternative implementation. This is an
existing limitation that also applies to the legacy hwcaps processing
for ld.so.cache.
Reviewed-by: Adhemerval Zanella <adhemerval.zanella@linaro.org>
Libraries from these subdirectories are added to the cache
with a special hwcap bit DL_CACHE_HWCAP_EXTENSION, so that
they are ignored by older dynamic loaders.
Reviewed-by: Adhemerval Zanella <adhemerval.zanella@linaro.org>
This simplifies the string table construction in elf/cache.c
because there is no more need to keep track of offsets explicitly;
the string table implementation does this internally.
This change slightly reduces the size of the cache on disk. The
file format does not change as a result. The strings are
null-terminated, without explicit length, so tail merging is
transparent to readers.
Reviewed-by: Adhemerval Zanella <adhemerval.zanella@linaro.org>
This will be used in ldconfig to reduce the ld.so.cache size slightly.
Tail merging is an optimization where a pointer points into another
string if the first string is a suffix of the second string.
The hash function FNV-1a was chosen because it is simple and achieves
good dispersion even for short strings (so that the hash table bucket
count can be a power of two). It is clearly superior to the hsearch
hash and the ELF hash in this regard.
The hash table uses chaining for collision resolution.
Reviewed-by: Adhemerval Zanella <adhemerval.zanella@linaro.org>
A previously unused new-format header field is used to record
the address of an extension directory.
This change adds a demo extension which records the version of
ldconfig which builds a file.
Reviewed-by: Adhemerval Zanella <adhemerval.zanella@linaro.org>
Use a reserved byte in the new format cache header to indicate whether
the file is in little endian or big endian format. Eventually, this
information could be used to provide a unified cache for qemu-user
and similiar scenarios.
Reviewed-by: Adhemerval Zanella <adhemerval.zanella@linaro.org>
This hacks non-power-set processing into _dl_important_hwcaps.
Once the legacy hwcaps handling goes away, the subdirectory
handling needs to be reworked, but it is premature to do this
while both approaches are still supported.
ld.so supports two new arguments, --glibc-hwcaps-prepend and
--glibc-hwcaps-mask. Each accepts a colon-separated list of
glibc-hwcaps subdirectory names. The prepend option adds additional
subdirectories that are searched first, in the specified order. The
mask option restricts the automatically selected subdirectories to
those listed in the option argument. For example, on systems where
/usr/lib64 is on the library search path,
--glibc-hwcaps-prepend=valgrind:debug causes the dynamic loader to
search the directories /usr/lib64/glibc-hwcaps/valgrind and
/usr/lib64/glibc-hwcaps/debug just before /usr/lib64 is searched.
Reviewed-by: Adhemerval Zanella <adhemerval.zanella@linaro.org>
The previous definition of THREAD_SELF did not tell the compiler
that %fs (or %gs) usage is invalid for the !DL_LOOKUP_GSCOPE_LOCK
case in _dl_lookup_symbol_x. As a result, ld.so could try to use the
TCB before it was initialized.
As the comment in tls.h explains, asm volatile is undesirable here.
Using the __seg_fs (or __seg_gs) namespace does not interfere with
optimization, and expresses that THREAD_SELF is potentially trapping.
This reverts commit 81b83ff61f to move
__xmknod{at} back to default symbols. ABIs with default symbol version
of 2.33 or newer (such as riscv32) continue to just provide the mknod*
symbols.
The idea is to not force static libraries built against old glibc
to update against new glibcs (since they reference the the
xmknod{at} symbols).
Checked on x86_64-linux-gnu and i686-linux-gnu.
This reverts commit 20b39d5946 to move
{f}xstat{at} back to default symbols. ABIs with default symbol version
of 2.33 or newer (such as riscv32) continue to just provide the stat
symbols.
The idea is to not force static libraries built against old glibc
to update against new glibcs (since they reference the old
{f}xstat{at} symbols).
Checked on x86_64-linux-gnu and i686-linux-gnu.
The earlier implementation of this, __lll_clocklock, calls lll_clockwait
that doesn't return the futex syscall error codes. It always tries again
if that fails.
However in the current implementation, when the futex returns EAGAIN,
__futex_clocklock64 will also return EGAIN, even if the futex is taken.
This patch fixes the EAGAIN issue and also adds a check for EINTR. As
futex syscall can return EINTR if the thread is interrupted by a signal.
In this case I'm assuming the function should continue trying to lock as
there is no mention to about it on POSIX. Also add a test for both
scenarios.
Reviewed-by: Adhemerval Zanella <adhemerval.zanella@linaro.org>
Programatically generate simple wrappers for interesting libm *f128
objects. Selected functions are transcendental functions or
those with trivial compiler builtins. This can result in a 2-3x
speedup (e.g logf128 and expf128).
A second set of implementation files are generated which include
the first implementation encountered along the search path. This
usually works, except when a wrapper is overriden and makefile
search order slightly diverges from include order. Likewise,
wrapper object files are created for each generated file. These
hold the ifunc selection routines which export ABI.
Next, several shared headers are intercepted to control renaming of
asm function redirects are used first, and sometimes macro renames
if the former is impractical.
Notably, if the request machine supports hardware IEEE128 (i.e POWER9
and newer) this ifunc machinery is disabled. Likewise existing
ifunc support for float128 is consolidated into this (e.g sqrtf128
and fmaf128).
Reviewed-by: Tulio Magno Quites Machado Filho <tuliom@linux.ibm.com>
The aio_suspend function has been converted to support 64 bit time.
This change uses (in aio_misc.h):
- __futex_abstimed_wait64 (instead of futex_reltimed_wait)
- __futex_abstimed_wait_cancellable64
(instead of futex_reltimed_wait_cancellable)
from ./sysdeps/nptl/futex-helpers.h
The aio_suspend() accepts relative timeout, which then is converted to
absolute one.
The i686-gnu port (HURD) do not define DONT_NEED_AIO_MISC_COND and as it
doesn't (yet) support 64 bit time it uses not converted
pthread_cond_timedwait().
The __aio_suspend() is supposed to be run on ports with __TIMESIZE !=64 and
__WORDSIZE==32. It internally utilizes __aio_suspend_time64() and hence the
conversion from 32 bit struct timespec to 64 bit one is required.
For ports supporting 64 bit time the __aio_suspend_time64() will be used
either via alias (to __aio_suspend when __TIMESIZE==64) or redirection
(when -D_TIME_BITS=64 is passed).
Build tests:
./src/scripts/build-many-glibcs.py glibcs
Reviewed-by: Alistair Francis <alistair.francis@wdc.com>
Reviewed-by: Adhemerval Zanella <adhemerval.zanella@linaro.org>
Some futex-internal calls require additional check for EOVERFLOW (as
indicated by [1] [2] [3]). For both mutex and rwlock code, EOVERFLOW is
handle as ETIMEDOUT; since it indicate to the caller that the blocking
operation could not be issued.
For mutex it avoids a possible issue where PTHREAD_MUTEX_ROBUST_* might
assume EOVERFLOW indicate futex has succeed, and for PTHREAD_MUTEX_PP_*
it avoid a potential busy infinite loop. For rwlock and semaphores, it
also avoids potential busy infinite loops.
Checked on x86_64-linux-gnu and i686-linux-gnu, although EOVERFLOW
won't be possible with current usage (since all timeouts on 32-bit
architectures with 32-bit time_t support will be in the range of
32-bit time_t).
[1] https://sourceware.org/pipermail/libc-alpha/2020-November/120079.html
[2] https://sourceware.org/pipermail/libc-alpha/2020-November/120080.html
[3] https://sourceware.org/pipermail/libc-alpha/2020-November/120127.html
The 878fe624d4 changed lll_futex_timed_wait, which expects a relative
timeout, with a __futex_abstimed_wait64, which expects an absolute
timeout. However the code still passes a relative timeout.
Also, the PTHREAD_PRIO_PROTECT support for clocks different than
CLOCK_REALTIME was broken since the inclusion of
pthread_mutex_clocklock (9d20e22e46) since lll_futex_timed_wait
always use CLOCK_REALTIME.
This patch fixes by removing the relative time calculation. It
also adds some xtests that tests both thread and inter-process
usage.
Checked on x86_64-linux-gnu.
The commit 605f38177d (sh: Split BE/LE abilist) did not take in
consideration the SH4 fpu support.
Checked with a build for sh4-linux-gnu and manually checked that
the implementations at sysdeps/sh/sh4/fpu/ are selected.
John Paul Adrian Glaubitz also confirmed it fixes the build issues
he encontered.
The nopenfd value is used as argument for the internal buffer on
ftw_statup, which is allocated with alloca and might trigger
a stack overflow for large values. This patch replaces the memory
allocation to use malloc instead.
Checked on x86_64-linux-gnu.
Reviewed-by: Adhemerval Zanella <adhemerval.zanella@linaro.org>
The align the GNU extension with the others one that accept specify
which clock to wait for (such as pthread_mutex_clocklock).
Check on x86_64-linux-gnu.
Reviewed-by: Lukasz Majewski <lukma@denx.de>
Linux futex FUTEX_LOCK_PI operation only supports CLOCK_REALTIME,
so pthread_mutex_clocklock operation with priority aware mutexes
may fail depending of the input timeout.
Also, it is not possible to convert a CLOCK_MONOTONIC to a
CLOCK_REALTIME due the possible wall clock time change which might
invalid the requested timeout.
Checked on x86_64-linux-gnu and i686-linux-gnu.
Reviewed-by: Lukasz Majewski <lukma@denx.de>
The idea is to make NPTL implementation to use on the functions
provided by futex-internal.h.
Checked on x86_64-linux-gnu and i686-linux-gnu.
Reviewed-by: Lukasz Majewski <lukma@denx.de>
The idea is to make NPTL implementation to use on the functions
provided by futex-internal.h.
Checked on x86_64-linux-gnu and i686-linux-gnu.
Reviewed-by: Lukasz Majewski <lukma@denx.de>
The idea is to make NPTL implementation to use on the functions
provided by futex-internal.h.
Checked on x86_64-linux-gnu and i686-linux-gnu.
Reviewed-by: Lukasz Majewski <lukma@denx.de>
For non null timeouts, the __futex_clocklock_wait64 creates an a
relative timeout by subtracting the current time from the input
argument. The same behavior can be obtained with FUTEX_WAIT_BITSET
without the need to calculate the relative timeout. Besides consolidate
the code it also avoid the possible relative timeout issues [1].
The __futex_abstimed_wait64 needs also to return EINVAL syscall
errors.
Checked on x86_64-linux-gnu and i686-linux-gnu.
[1] https://sourceware.org/pipermail/libc-alpha/2020-November/119881.html
Reviewed-by: Lukasz Majewski <lukma@denx.de>
And add a small optimization to avoid setting the operation for the
32-bit time fallback operation.
Checked on x86_64-linux-gnu and i686-linux-gnu.
Reviewed-by: Lukasz Majewski <lukma@denx.de>
