glibc/sysdeps/unix/sysv/linux/kernel-posix-timers.h

118 lines
3.5 KiB
C

/* 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
not, see <https://www.gnu.org/licenses/>. */
#include <pthread.h>
#include <setjmp.h>
#include <signal.h>
#include <sys/types.h>
/* Nonzero if the system calls are not available. */
extern int __no_posix_timers attribute_hidden;
/* Callback to start helper thread. */
extern void __timer_start_helper_thread (void) attribute_hidden;
/* Control variable for helper thread creation. */
extern pthread_once_t __timer_helper_once attribute_hidden;
/* Called from fork so that the new subprocess re-creates the
notification thread if necessary. */
void __timer_fork_subprocess (void) attribute_hidden;
/* TID of the helper thread. */
extern pid_t __timer_helper_tid attribute_hidden;
/* List of active SIGEV_THREAD timers. */
extern struct timer *__timer_active_sigev_thread attribute_hidden;
/* Lock for __timer_active_sigev_thread. */
extern pthread_mutex_t __timer_active_sigev_thread_lock attribute_hidden;
extern __typeof (timer_create) __timer_create;
libc_hidden_proto (__timer_create)
extern __typeof (timer_delete) __timer_delete;
libc_hidden_proto (__timer_delete)
extern __typeof (timer_getoverrun) __timer_getoverrun;
libc_hidden_proto (__timer_getoverrun)
/* Type of timers in the kernel. */
typedef int kernel_timer_t;
/* Internal representation of SIGEV_THREAD timer. */
struct timer
{
kernel_timer_t ktimerid;
void (*thrfunc) (sigval_t);
sigval_t sival;
pthread_attr_t attr;
/* Next element in list of active SIGEV_THREAD timers. */
struct timer *next;
};
/* 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 the MSB bit of the returned
'timer_t' to indicate the timer handles a SIGEV_THREAD. */
static inline timer_t
kernel_timer_to_timerid (kernel_timer_t ktimerid)
{
return (timer_t) ((intptr_t) ktimerid);
}
static inline timer_t
timer_to_timerid (struct timer *ptr)
{
return (timer_t) (INTPTR_MIN | (uintptr_t) ptr >> 1);
}
static inline bool
timer_is_sigev_thread (timer_t timerid)
{
return (intptr_t) timerid < 0;
}
static inline struct timer *
timerid_to_timer (timer_t timerid)
{
return (struct timer *)((uintptr_t) timerid << 1);
}
static inline kernel_timer_t
timerid_to_kernel_timer (timer_t timerid)
{
if (timer_is_sigev_thread (timerid))
return timerid_to_timer (timerid)->ktimerid;
else
return (kernel_timer_t) ((uintptr_t) timerid);
}
/* New targets use int instead of timer_t. The difference only
matters on 64-bit targets. */
#include <timer_t_was_int_compat.h>
#if TIMER_T_WAS_INT_COMPAT
# define OLD_TIMER_MAX 256
extern timer_t __timer_compat_list[OLD_TIMER_MAX];
#endif