mirror of
https://sourceware.org/git/glibc.git
synced 2024-11-26 15:00:06 +00:00
a1bdd81664
The main drive is to optimize the internal usage and required size when sigset_t is embedded in other data structures. On Linux, the current supported signal set requires up to 8 bytes (16 on mips), was lower than the user defined sigset_t (128 bytes). A new internal type internal_sigset_t is added, along with the functions to operate on it similar to the ones for sigset_t. The internal-signals.h is also refactored to remove unused functions Besides small stack usage on some functions (posix_spawn, abort) it lower the struct pthread by about 120 bytes (112 on mips). Checked on x86_64-linux-gnu. Reviewed-by: Arjun Shankar <arjun@redhat.com>
155 lines
4.0 KiB
C
155 lines
4.0 KiB
C
/* Copyright (C) 2003-2022 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
|
|
not, see <https://www.gnu.org/licenses/>. */
|
|
|
|
#include <errno.h>
|
|
#include <setjmp.h>
|
|
#include <signal.h>
|
|
#include <stdbool.h>
|
|
#include <sysdep-cancel.h>
|
|
#include <pthreadP.h>
|
|
#include "kernel-posix-timers.h"
|
|
|
|
|
|
/* List of active SIGEV_THREAD timers. */
|
|
struct timer *__timer_active_sigev_thread;
|
|
|
|
/* Lock for _timer_active_sigev_thread. */
|
|
pthread_mutex_t __timer_active_sigev_thread_lock = PTHREAD_MUTEX_INITIALIZER;
|
|
|
|
struct thread_start_data
|
|
{
|
|
void (*thrfunc) (sigval_t);
|
|
sigval_t sival;
|
|
};
|
|
|
|
|
|
/* Helper thread to call the user-provided function. */
|
|
static void *
|
|
timer_sigev_thread (void *arg)
|
|
{
|
|
signal_unblock_sigtimer ();
|
|
|
|
struct thread_start_data *td = (struct thread_start_data *) arg;
|
|
void (*thrfunc) (sigval_t) = td->thrfunc;
|
|
sigval_t sival = td->sival;
|
|
|
|
/* The TD object was allocated in timer_helper_thread. */
|
|
free (td);
|
|
|
|
/* Call the user-provided function. */
|
|
thrfunc (sival);
|
|
|
|
return NULL;
|
|
}
|
|
|
|
|
|
/* Helper function to support starting threads for SIGEV_THREAD. */
|
|
static _Noreturn void *
|
|
timer_helper_thread (void *arg)
|
|
{
|
|
/* Endless loop of waiting for signals. The loop is only ended when
|
|
the thread is canceled. */
|
|
while (1)
|
|
{
|
|
siginfo_t si;
|
|
|
|
while (__sigwaitinfo (&sigtimer_set, &si) < 0);
|
|
if (si.si_code == SI_TIMER)
|
|
{
|
|
struct timer *tk = (struct timer *) si.si_ptr;
|
|
|
|
/* Check the timer is still used and will not go away
|
|
while we are reading the values here. */
|
|
__pthread_mutex_lock (&__timer_active_sigev_thread_lock);
|
|
|
|
struct timer *runp = __timer_active_sigev_thread;
|
|
while (runp != NULL)
|
|
if (runp == tk)
|
|
break;
|
|
else
|
|
runp = runp->next;
|
|
|
|
if (runp != NULL)
|
|
{
|
|
struct thread_start_data *td = malloc (sizeof (*td));
|
|
|
|
/* There is not much we can do if the allocation fails. */
|
|
if (td != NULL)
|
|
{
|
|
/* This is the signal we are waiting for. */
|
|
td->thrfunc = tk->thrfunc;
|
|
td->sival = tk->sival;
|
|
|
|
pthread_t th;
|
|
__pthread_create (&th, &tk->attr, timer_sigev_thread, td);
|
|
}
|
|
}
|
|
|
|
__pthread_mutex_unlock (&__timer_active_sigev_thread_lock);
|
|
}
|
|
}
|
|
}
|
|
|
|
|
|
/* Control variable for helper thread creation. */
|
|
pthread_once_t __timer_helper_once = PTHREAD_ONCE_INIT;
|
|
|
|
|
|
/* TID of the helper thread. */
|
|
pid_t __timer_helper_tid;
|
|
|
|
|
|
/* Reset variables so that after a fork a new helper thread gets started. */
|
|
void
|
|
__timer_fork_subprocess (void)
|
|
{
|
|
__timer_helper_once = PTHREAD_ONCE_INIT;
|
|
__timer_helper_tid = 0;
|
|
}
|
|
|
|
|
|
void
|
|
__timer_start_helper_thread (void)
|
|
{
|
|
/* The helper thread needs only very little resources
|
|
and should go away automatically when canceled. */
|
|
pthread_attr_t attr;
|
|
__pthread_attr_init (&attr);
|
|
__pthread_attr_setstacksize (&attr, __pthread_get_minstack (&attr));
|
|
|
|
/* Block all signals in the helper thread but SIGSETXID. */
|
|
sigset_t ss;
|
|
__sigfillset (&ss);
|
|
__sigdelset (&ss, SIGSETXID);
|
|
int res = __pthread_attr_setsigmask_internal (&attr, &ss);
|
|
if (res != 0)
|
|
{
|
|
__pthread_attr_destroy (&attr);
|
|
return;
|
|
}
|
|
|
|
/* Create the helper thread for this timer. */
|
|
pthread_t th;
|
|
res = __pthread_create (&th, &attr, timer_helper_thread, NULL);
|
|
if (res == 0)
|
|
/* We managed to start the helper thread. */
|
|
__timer_helper_tid = ((struct pthread *) th)->tid;
|
|
|
|
/* No need for the attribute anymore. */
|
|
__pthread_attr_destroy (&attr);
|
|
}
|