glibc/sysdeps/unix/sysv/linux/timer_create.c

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/* Copyright (C) 2003-2021 Free Software Foundation, Inc.
This file is part of the GNU C Library.
Contributed by Ulrich Drepper <drepper@redhat.com>, 2003.
The GNU C Library is free software; you can redistribute it and/or
modify it under the terms of the GNU Lesser General Public License as
published by the Free Software Foundation; either version 2.1 of the
License, or (at your option) any later version.
The GNU C Library is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
Lesser General Public License for more details.
You should have received a copy of the GNU Lesser General Public
License along with the GNU C Library; see the file COPYING.LIB. If
Prefer https to http for gnu.org and fsf.org URLs Also, change sources.redhat.com to sourceware.org. This patch was automatically generated by running the following shell script, which uses GNU sed, and which avoids modifying files imported from upstream: sed -ri ' s,(http|ftp)(://(.*\.)?(gnu|fsf|sourceware)\.org($|[^.]|\.[^a-z])),https\2,g s,(http|ftp)(://(.*\.)?)sources\.redhat\.com($|[^.]|\.[^a-z]),https\2sourceware.org\4,g ' \ $(find $(git ls-files) -prune -type f \ ! -name '*.po' \ ! -name 'ChangeLog*' \ ! -path COPYING ! -path COPYING.LIB \ ! -path manual/fdl-1.3.texi ! -path manual/lgpl-2.1.texi \ ! -path manual/texinfo.tex ! -path scripts/config.guess \ ! -path scripts/config.sub ! -path scripts/install-sh \ ! -path scripts/mkinstalldirs ! -path scripts/move-if-change \ ! -path INSTALL ! -path locale/programs/charmap-kw.h \ ! -path po/libc.pot ! -path sysdeps/gnu/errlist.c \ ! '(' -name configure \ -execdir test -f configure.ac -o -f configure.in ';' ')' \ ! '(' -name preconfigure \ -execdir test -f preconfigure.ac ';' ')' \ -print) and then by running 'make dist-prepare' to regenerate files built from the altered files, and then executing the following to cleanup: chmod a+x sysdeps/unix/sysv/linux/riscv/configure # Omit irrelevant whitespace and comment-only changes, # perhaps from a slightly-different Autoconf version. git checkout -f \ sysdeps/csky/configure \ sysdeps/hppa/configure \ sysdeps/riscv/configure \ sysdeps/unix/sysv/linux/csky/configure # Omit changes that caused a pre-commit check to fail like this: # remote: *** error: sysdeps/powerpc/powerpc64/ppc-mcount.S: trailing lines git checkout -f \ sysdeps/powerpc/powerpc64/ppc-mcount.S \ sysdeps/unix/sysv/linux/s390/s390-64/syscall.S # Omit change that caused a pre-commit check to fail like this: # remote: *** error: sysdeps/sparc/sparc64/multiarch/memcpy-ultra3.S: last line does not end in newline git checkout -f sysdeps/sparc/sparc64/multiarch/memcpy-ultra3.S
2019-09-07 05:40:42 +00:00
not, see <https://www.gnu.org/licenses/>. */
#include <errno.h>
#include <pthread.h>
#include <signal.h>
#include <stdlib.h>
#include <string.h>
#include <time.h>
#include <sysdep.h>
#include <internaltypes.h>
#include <pthreadP.h>
#include "kernel-posix-timers.h"
* rt/tst-cpuclock1.c: New file. * rt/tst-cpuclock2.c: New file. * rt/tst-cputimer1.c: New file. * rt/tst-cputimer2.c: New file. * rt/tst-cputimer3.c: New file. * rt/Makefile (tests): Add them. * sysdeps/unix/sysv/linux/kernel-posix-cpu-timers.h: New file. * sysdeps/unix/sysv/linux/clock_getcpuclockid.c: New file. * sysdeps/unix/sysv/linux/ia64/clock_getcpuclockid.c (HAS_CPUCLOCK): New macro. (clock_getcpuclockid): Function removed. #include the new linux file to define it instead. * sysdeps/unix/clock_gettime.c [HP_TIMING_AVAIL] (hp_timing_gettime): New function, broken out of ... (clock_gettime) [HP_TIMING_AVAIL]: ... here. Call it. (realtime_gettime): New function, broken out of ... (clock_gettime) [! HANDLED_REALTIME]: ... here. Call it. (clock_gettime) [SYSDEP_GETTIME_CPU]: Use new macro in default case. * sysdeps/unix/sysv/linux/clock_gettime.c (SYSCALL_GETTIME): New macro. (SYSDEP_GETTIME_CPUTIME): New macro. (SYSDEP_GETTIME): Use both. [! __ASSUME_POSIX_TIMERS] (maybe_syscall_gettime): New function, broken out of ... (SYSDEP_GETTIME): ... here. Use it. [__NR_clock_gettime] (HANDLED_CPUTIME): Define it. (SYSDEP_GETTIME_CPUTIME): New macro. Handle CPU timers by trying kernel support and falling back to hp-timing code. * sysdeps/posix/clock_getres.c [HP_TIMING_AVAIL] (hp_timing_getres): New function, broken out of ... (clock_getres) [HP_TIMING_AVAIL]: ... here. Call it. (realtime_getres): New function, broken out of ... (clock_getres) [! HANDLED_REALTIME]: ... here. Call it. (clock_getres) [SYSDEP_GETRES_CPU]: Use new macro in default case. * sysdeps/unix/sysv/linux/clock_getres.c (SYSCALL_GETRES): New macro. (SYSDEP_GETRES_CPUTIME): New macro. (SYSDEP_GETRES): Use both. [! __ASSUME_POSIX_TIMERS] (maybe_syscall_getres): New function, broken out of ... (SYSDEP_GETRES): ... here. Use it. [__NR_clock_getres] (HANDLED_CPUTIME): Define it. (SYSDEP_GETRES_CPUTIME): New macro. Handle CPU timers by trying kernel support and falling back to hp-timing code. * sysdeps/unix/sysv/linux/clock_nanosleep.c: Handle CLOCK_PROCESS_CPUTIME_ID and CLOCK_PROCESS_THREAD_ID specially, translating to the kernel clockid_t for our own process/thread clock.
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#include "kernel-posix-cpu-timers.h"
#include <shlib-compat.h>
int
___timer_create (clockid_t clock_id, struct sigevent *evp, timer_t *timerid)
{
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{
clockid_t syscall_clockid = (clock_id == CLOCK_PROCESS_CPUTIME_ID
? MAKE_PROCESS_CPUCLOCK (0, CPUCLOCK_SCHED)
: clock_id == CLOCK_THREAD_CPUTIME_ID
? MAKE_THREAD_CPUCLOCK (0, CPUCLOCK_SCHED)
: clock_id);
/* If the user wants notification via a thread we need to handle
this special. */
if (evp == NULL
|| __builtin_expect (evp->sigev_notify != SIGEV_THREAD, 1))
{
struct sigevent local_evp;
if (evp == NULL)
{
/* The kernel has to pass up the timer ID which is a
userlevel object. Therefore we cannot leave it up to
the kernel to determine it. */
local_evp.sigev_notify = SIGEV_SIGNAL;
local_evp.sigev_signo = SIGALRM;
posix: Fix -Warray-bounds instances building timer_create [BZ #26687] GCC 11 -Warray-bounds triggers invalid warnings when building Linux timer_create.c: ../sysdeps/unix/sysv/linux/timer_create.c: In function '__timer_create_new': ../sysdeps/unix/sysv/linux/timer_create.c:83:17: warning: array subscript 'struct timer[0]' is partly outside array bounds of 'unsigned char[8]' [-Warray-bounds] 83 | newp->sigev_notify = (evp != NULL | ^~ ../sysdeps/unix/sysv/linux/timer_create.c:59:47: note: referencing an object of size 8 allocated by 'malloc' 59 | struct timer *newp = (struct timer *) malloc (offsetof (struct timer, | ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ 60 | thrfunc)); | ~~~~~~~~~ The struct allocated for !SIGEV_THREAD timers only requires two 'int' fields (sigev_notify and ktimerid) and the offsetof trick tries minimize the memory usage by only allocation the required size. However, although the resulting size is suffice for !SIGEV_THREAD time, accessing the partially allocated object is error-prone and UB. This patch fixes both issues by embedding the information whether the timer if a SIGEV_THREAD in the returned 'timer_t'. For !SIGEV_THREAD, the resulting 'timer_t' is the returned kernel timer identifer (kernel_timer_t), while for SIGEV_THREAD it uses the fact malloc returns at least _Alignof (max_align_t) pointers plus that valid kernel_timer_t are always positive to set MSB bit of the returned 'timer_t' to indicate the timer handles a SIGEV_THREAD. It allows to remove the memory allocation for !SIGEV_THREAD and also remove the 'sigev_notify' field from 'struct timer'. Checked on x86_64-linux-gnu and i686-linux-gnu.
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local_evp.sigev_value.sival_ptr = NULL;
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evp = &local_evp;
}
kernel_timer_t ktimerid;
posix: Fix -Warray-bounds instances building timer_create [BZ #26687] GCC 11 -Warray-bounds triggers invalid warnings when building Linux timer_create.c: ../sysdeps/unix/sysv/linux/timer_create.c: In function '__timer_create_new': ../sysdeps/unix/sysv/linux/timer_create.c:83:17: warning: array subscript 'struct timer[0]' is partly outside array bounds of 'unsigned char[8]' [-Warray-bounds] 83 | newp->sigev_notify = (evp != NULL | ^~ ../sysdeps/unix/sysv/linux/timer_create.c:59:47: note: referencing an object of size 8 allocated by 'malloc' 59 | struct timer *newp = (struct timer *) malloc (offsetof (struct timer, | ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ 60 | thrfunc)); | ~~~~~~~~~ The struct allocated for !SIGEV_THREAD timers only requires two 'int' fields (sigev_notify and ktimerid) and the offsetof trick tries minimize the memory usage by only allocation the required size. However, although the resulting size is suffice for !SIGEV_THREAD time, accessing the partially allocated object is error-prone and UB. This patch fixes both issues by embedding the information whether the timer if a SIGEV_THREAD in the returned 'timer_t'. For !SIGEV_THREAD, the resulting 'timer_t' is the returned kernel timer identifer (kernel_timer_t), while for SIGEV_THREAD it uses the fact malloc returns at least _Alignof (max_align_t) pointers plus that valid kernel_timer_t are always positive to set MSB bit of the returned 'timer_t' to indicate the timer handles a SIGEV_THREAD. It allows to remove the memory allocation for !SIGEV_THREAD and also remove the 'sigev_notify' field from 'struct timer'. Checked on x86_64-linux-gnu and i686-linux-gnu.
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if (INLINE_SYSCALL_CALL (timer_create, syscall_clockid, evp,
&ktimerid) == -1)
return -1;
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posix: Fix -Warray-bounds instances building timer_create [BZ #26687] GCC 11 -Warray-bounds triggers invalid warnings when building Linux timer_create.c: ../sysdeps/unix/sysv/linux/timer_create.c: In function '__timer_create_new': ../sysdeps/unix/sysv/linux/timer_create.c:83:17: warning: array subscript 'struct timer[0]' is partly outside array bounds of 'unsigned char[8]' [-Warray-bounds] 83 | newp->sigev_notify = (evp != NULL | ^~ ../sysdeps/unix/sysv/linux/timer_create.c:59:47: note: referencing an object of size 8 allocated by 'malloc' 59 | struct timer *newp = (struct timer *) malloc (offsetof (struct timer, | ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ 60 | thrfunc)); | ~~~~~~~~~ The struct allocated for !SIGEV_THREAD timers only requires two 'int' fields (sigev_notify and ktimerid) and the offsetof trick tries minimize the memory usage by only allocation the required size. However, although the resulting size is suffice for !SIGEV_THREAD time, accessing the partially allocated object is error-prone and UB. This patch fixes both issues by embedding the information whether the timer if a SIGEV_THREAD in the returned 'timer_t'. For !SIGEV_THREAD, the resulting 'timer_t' is the returned kernel timer identifer (kernel_timer_t), while for SIGEV_THREAD it uses the fact malloc returns at least _Alignof (max_align_t) pointers plus that valid kernel_timer_t are always positive to set MSB bit of the returned 'timer_t' to indicate the timer handles a SIGEV_THREAD. It allows to remove the memory allocation for !SIGEV_THREAD and also remove the 'sigev_notify' field from 'struct timer'. Checked on x86_64-linux-gnu and i686-linux-gnu.
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*timerid = kernel_timer_to_timerid (ktimerid);
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}
else
{
/* Create the helper thread. */
__pthread_once (&__timer_helper_once, __timer_start_helper_thread);
if (__timer_helper_tid == 0)
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{
/* No resources to start the helper thread. */
__set_errno (EAGAIN);
return -1;
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}
posix: Fix -Warray-bounds instances building timer_create [BZ #26687] GCC 11 -Warray-bounds triggers invalid warnings when building Linux timer_create.c: ../sysdeps/unix/sysv/linux/timer_create.c: In function '__timer_create_new': ../sysdeps/unix/sysv/linux/timer_create.c:83:17: warning: array subscript 'struct timer[0]' is partly outside array bounds of 'unsigned char[8]' [-Warray-bounds] 83 | newp->sigev_notify = (evp != NULL | ^~ ../sysdeps/unix/sysv/linux/timer_create.c:59:47: note: referencing an object of size 8 allocated by 'malloc' 59 | struct timer *newp = (struct timer *) malloc (offsetof (struct timer, | ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ 60 | thrfunc)); | ~~~~~~~~~ The struct allocated for !SIGEV_THREAD timers only requires two 'int' fields (sigev_notify and ktimerid) and the offsetof trick tries minimize the memory usage by only allocation the required size. However, although the resulting size is suffice for !SIGEV_THREAD time, accessing the partially allocated object is error-prone and UB. This patch fixes both issues by embedding the information whether the timer if a SIGEV_THREAD in the returned 'timer_t'. For !SIGEV_THREAD, the resulting 'timer_t' is the returned kernel timer identifer (kernel_timer_t), while for SIGEV_THREAD it uses the fact malloc returns at least _Alignof (max_align_t) pointers plus that valid kernel_timer_t are always positive to set MSB bit of the returned 'timer_t' to indicate the timer handles a SIGEV_THREAD. It allows to remove the memory allocation for !SIGEV_THREAD and also remove the 'sigev_notify' field from 'struct timer'. Checked on x86_64-linux-gnu and i686-linux-gnu.
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struct timer *newp = malloc (sizeof (struct timer));
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if (newp == NULL)
return -1;
/* Copy the thread parameters the user provided. */
newp->sival = evp->sigev_value;
newp->thrfunc = evp->sigev_notify_function;
/* We cannot simply copy the thread attributes since the
implementation might keep internal information for
each instance. */
__pthread_attr_init (&newp->attr);
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if (evp->sigev_notify_attributes != NULL)
{
struct pthread_attr *nattr;
struct pthread_attr *oattr;
nattr = (struct pthread_attr *) &newp->attr;
oattr = (struct pthread_attr *) evp->sigev_notify_attributes;
nattr->schedparam = oattr->schedparam;
nattr->schedpolicy = oattr->schedpolicy;
nattr->flags = oattr->flags;
nattr->guardsize = oattr->guardsize;
nattr->stackaddr = oattr->stackaddr;
nattr->stacksize = oattr->stacksize;
}
/* In any case set the detach flag. */
__pthread_attr_setdetachstate (&newp->attr, PTHREAD_CREATE_DETACHED);
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/* Create the event structure for the kernel timer. */
struct sigevent sev =
{ .sigev_value.sival_ptr = newp,
.sigev_signo = SIGTIMER,
.sigev_notify = SIGEV_SIGNAL | SIGEV_THREAD_ID,
._sigev_un = { ._pad = { [0] = __timer_helper_tid } } };
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/* Create the timer. */
int res;
posix: Fix -Warray-bounds instances building timer_create [BZ #26687] GCC 11 -Warray-bounds triggers invalid warnings when building Linux timer_create.c: ../sysdeps/unix/sysv/linux/timer_create.c: In function '__timer_create_new': ../sysdeps/unix/sysv/linux/timer_create.c:83:17: warning: array subscript 'struct timer[0]' is partly outside array bounds of 'unsigned char[8]' [-Warray-bounds] 83 | newp->sigev_notify = (evp != NULL | ^~ ../sysdeps/unix/sysv/linux/timer_create.c:59:47: note: referencing an object of size 8 allocated by 'malloc' 59 | struct timer *newp = (struct timer *) malloc (offsetof (struct timer, | ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ 60 | thrfunc)); | ~~~~~~~~~ The struct allocated for !SIGEV_THREAD timers only requires two 'int' fields (sigev_notify and ktimerid) and the offsetof trick tries minimize the memory usage by only allocation the required size. However, although the resulting size is suffice for !SIGEV_THREAD time, accessing the partially allocated object is error-prone and UB. This patch fixes both issues by embedding the information whether the timer if a SIGEV_THREAD in the returned 'timer_t'. For !SIGEV_THREAD, the resulting 'timer_t' is the returned kernel timer identifer (kernel_timer_t), while for SIGEV_THREAD it uses the fact malloc returns at least _Alignof (max_align_t) pointers plus that valid kernel_timer_t are always positive to set MSB bit of the returned 'timer_t' to indicate the timer handles a SIGEV_THREAD. It allows to remove the memory allocation for !SIGEV_THREAD and also remove the 'sigev_notify' field from 'struct timer'. Checked on x86_64-linux-gnu and i686-linux-gnu.
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res = INTERNAL_SYSCALL_CALL (timer_create, syscall_clockid, &sev,
&newp->ktimerid);
if (INTERNAL_SYSCALL_ERROR_P (res))
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{
posix: Fix -Warray-bounds instances building timer_create [BZ #26687] GCC 11 -Warray-bounds triggers invalid warnings when building Linux timer_create.c: ../sysdeps/unix/sysv/linux/timer_create.c: In function '__timer_create_new': ../sysdeps/unix/sysv/linux/timer_create.c:83:17: warning: array subscript 'struct timer[0]' is partly outside array bounds of 'unsigned char[8]' [-Warray-bounds] 83 | newp->sigev_notify = (evp != NULL | ^~ ../sysdeps/unix/sysv/linux/timer_create.c:59:47: note: referencing an object of size 8 allocated by 'malloc' 59 | struct timer *newp = (struct timer *) malloc (offsetof (struct timer, | ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ 60 | thrfunc)); | ~~~~~~~~~ The struct allocated for !SIGEV_THREAD timers only requires two 'int' fields (sigev_notify and ktimerid) and the offsetof trick tries minimize the memory usage by only allocation the required size. However, although the resulting size is suffice for !SIGEV_THREAD time, accessing the partially allocated object is error-prone and UB. This patch fixes both issues by embedding the information whether the timer if a SIGEV_THREAD in the returned 'timer_t'. For !SIGEV_THREAD, the resulting 'timer_t' is the returned kernel timer identifer (kernel_timer_t), while for SIGEV_THREAD it uses the fact malloc returns at least _Alignof (max_align_t) pointers plus that valid kernel_timer_t are always positive to set MSB bit of the returned 'timer_t' to indicate the timer handles a SIGEV_THREAD. It allows to remove the memory allocation for !SIGEV_THREAD and also remove the 'sigev_notify' field from 'struct timer'. Checked on x86_64-linux-gnu and i686-linux-gnu.
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free (newp);
__set_errno (INTERNAL_SYSCALL_ERRNO (res));
return -1;
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}
posix: Fix -Warray-bounds instances building timer_create [BZ #26687] GCC 11 -Warray-bounds triggers invalid warnings when building Linux timer_create.c: ../sysdeps/unix/sysv/linux/timer_create.c: In function '__timer_create_new': ../sysdeps/unix/sysv/linux/timer_create.c:83:17: warning: array subscript 'struct timer[0]' is partly outside array bounds of 'unsigned char[8]' [-Warray-bounds] 83 | newp->sigev_notify = (evp != NULL | ^~ ../sysdeps/unix/sysv/linux/timer_create.c:59:47: note: referencing an object of size 8 allocated by 'malloc' 59 | struct timer *newp = (struct timer *) malloc (offsetof (struct timer, | ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ 60 | thrfunc)); | ~~~~~~~~~ The struct allocated for !SIGEV_THREAD timers only requires two 'int' fields (sigev_notify and ktimerid) and the offsetof trick tries minimize the memory usage by only allocation the required size. However, although the resulting size is suffice for !SIGEV_THREAD time, accessing the partially allocated object is error-prone and UB. This patch fixes both issues by embedding the information whether the timer if a SIGEV_THREAD in the returned 'timer_t'. For !SIGEV_THREAD, the resulting 'timer_t' is the returned kernel timer identifer (kernel_timer_t), while for SIGEV_THREAD it uses the fact malloc returns at least _Alignof (max_align_t) pointers plus that valid kernel_timer_t are always positive to set MSB bit of the returned 'timer_t' to indicate the timer handles a SIGEV_THREAD. It allows to remove the memory allocation for !SIGEV_THREAD and also remove the 'sigev_notify' field from 'struct timer'. Checked on x86_64-linux-gnu and i686-linux-gnu.
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/* Add to the queue of active timers with thread delivery. */
__pthread_mutex_lock (&__timer_active_sigev_thread_lock);
newp->next = __timer_active_sigev_thread;
__timer_active_sigev_thread = newp;
__pthread_mutex_unlock (&__timer_active_sigev_thread_lock);
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posix: Fix -Warray-bounds instances building timer_create [BZ #26687] GCC 11 -Warray-bounds triggers invalid warnings when building Linux timer_create.c: ../sysdeps/unix/sysv/linux/timer_create.c: In function '__timer_create_new': ../sysdeps/unix/sysv/linux/timer_create.c:83:17: warning: array subscript 'struct timer[0]' is partly outside array bounds of 'unsigned char[8]' [-Warray-bounds] 83 | newp->sigev_notify = (evp != NULL | ^~ ../sysdeps/unix/sysv/linux/timer_create.c:59:47: note: referencing an object of size 8 allocated by 'malloc' 59 | struct timer *newp = (struct timer *) malloc (offsetof (struct timer, | ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ 60 | thrfunc)); | ~~~~~~~~~ The struct allocated for !SIGEV_THREAD timers only requires two 'int' fields (sigev_notify and ktimerid) and the offsetof trick tries minimize the memory usage by only allocation the required size. However, although the resulting size is suffice for !SIGEV_THREAD time, accessing the partially allocated object is error-prone and UB. This patch fixes both issues by embedding the information whether the timer if a SIGEV_THREAD in the returned 'timer_t'. For !SIGEV_THREAD, the resulting 'timer_t' is the returned kernel timer identifer (kernel_timer_t), while for SIGEV_THREAD it uses the fact malloc returns at least _Alignof (max_align_t) pointers plus that valid kernel_timer_t are always positive to set MSB bit of the returned 'timer_t' to indicate the timer handles a SIGEV_THREAD. It allows to remove the memory allocation for !SIGEV_THREAD and also remove the 'sigev_notify' field from 'struct timer'. Checked on x86_64-linux-gnu and i686-linux-gnu.
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*timerid = timer_to_timerid (newp);
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}
}
posix: Fix -Warray-bounds instances building timer_create [BZ #26687] GCC 11 -Warray-bounds triggers invalid warnings when building Linux timer_create.c: ../sysdeps/unix/sysv/linux/timer_create.c: In function '__timer_create_new': ../sysdeps/unix/sysv/linux/timer_create.c:83:17: warning: array subscript 'struct timer[0]' is partly outside array bounds of 'unsigned char[8]' [-Warray-bounds] 83 | newp->sigev_notify = (evp != NULL | ^~ ../sysdeps/unix/sysv/linux/timer_create.c:59:47: note: referencing an object of size 8 allocated by 'malloc' 59 | struct timer *newp = (struct timer *) malloc (offsetof (struct timer, | ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ 60 | thrfunc)); | ~~~~~~~~~ The struct allocated for !SIGEV_THREAD timers only requires two 'int' fields (sigev_notify and ktimerid) and the offsetof trick tries minimize the memory usage by only allocation the required size. However, although the resulting size is suffice for !SIGEV_THREAD time, accessing the partially allocated object is error-prone and UB. This patch fixes both issues by embedding the information whether the timer if a SIGEV_THREAD in the returned 'timer_t'. For !SIGEV_THREAD, the resulting 'timer_t' is the returned kernel timer identifer (kernel_timer_t), while for SIGEV_THREAD it uses the fact malloc returns at least _Alignof (max_align_t) pointers plus that valid kernel_timer_t are always positive to set MSB bit of the returned 'timer_t' to indicate the timer handles a SIGEV_THREAD. It allows to remove the memory allocation for !SIGEV_THREAD and also remove the 'sigev_notify' field from 'struct timer'. Checked on x86_64-linux-gnu and i686-linux-gnu.
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return 0;
}
versioned_symbol (libc, ___timer_create, timer_create, GLIBC_2_34);
libc_hidden_ver (___timer_create, __timer_create)
#if TIMER_T_WAS_INT_COMPAT
# if OTHER_SHLIB_COMPAT (librt, GLIBC_2_3_3, GLIBC_2_34)
compat_symbol (librt, ___timer_create, timer_create, GLIBC_2_3_3);
# endif
# if OTHER_SHLIB_COMPAT (librt, GLIBC_2_2, GLIBC_2_3_3)
timer_t __timer_compat_list[OLD_TIMER_MAX];
int
__timer_create_old (clockid_t clock_id, struct sigevent *evp, int *timerid)
{
timer_t newp;
int res = __timer_create (clock_id, evp, &newp);
if (res == 0)
{
int i;
for (i = 0; i < OLD_TIMER_MAX; ++i)
if (__timer_compat_list[i] == NULL
&& ! atomic_compare_and_exchange_bool_acq (&__timer_compat_list[i],
newp, NULL))
{
*timerid = i;
break;
}
if (__glibc_unlikely (i == OLD_TIMER_MAX))
{
/* No free slot. */
__timer_delete (newp);
__set_errno (EINVAL);
res = -1;
}
}
return res;
}
compat_symbol (librt, __timer_create_old, timer_create, GLIBC_2_2);
# endif /* OTHER_SHLIB_COMPAT */
#else /* !TIMER_T_WAS_INT_COMPAT */
# if OTHER_SHLIB_COMPAT (librt, GLIBC_2_2, GLIBC_2_34)
compat_symbol (librt, ___timer_create, timer_create, GLIBC_2_2);
# endif
#endif /* !TIMER_T_WAS_INT_COMPAT */