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

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/* Copyright (C) 2003-2024 Free Software Foundation, Inc.
This file is part of the GNU C Library.
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
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not, see <https://www.gnu.org/licenses/>. */
#include <errno.h>
#include <time.h>
#include <sysdep.h>
#include "kernel-posix-timers.h"
#include <shlib-compat.h>
int
___timer_getoverrun (timer_t timerid)
{
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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kernel_timer_t ktimerid = timerid_to_kernel_timer (timerid);
return INLINE_SYSCALL_CALL (timer_getoverrun, ktimerid);
}
versioned_symbol (libc, ___timer_getoverrun, timer_getoverrun, GLIBC_2_34);
libc_hidden_ver (___timer_getoverrun, __timer_getoverrun)
#if TIMER_T_WAS_INT_COMPAT
# if OTHER_SHLIB_COMPAT (librt, GLIBC_2_3_3, GLIBC_2_34)
compat_symbol (librt, ___timer_getoverrun, timer_getoverrun, GLIBC_2_3_3);
# endif
# if OTHER_SHLIB_COMPAT (librt, GLIBC_2_2, GLIBC_2_3_3)
int
__timer_getoverrun_old (int timerid)
{
return __timer_getoverrun (__timer_compat_list[timerid]);
}
compat_symbol (librt, __timer_getoverrun_old, timer_getoverrun, 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_getoverrun, timer_getoverrun, GLIBC_2_2);
# endif
#endif /* !TIMER_T_WAS_INT_COMPAT */