155 lines
4.4 KiB
C
155 lines
4.4 KiB
C
/* Copyright (C) 2003, 2004 Free Software Foundation, Inc.
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This file is part of the GNU C Library.
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Contributed by Ulrich Drepper <drepper@redhat.com>, 2003.
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The GNU C Library is free software; you can redistribute it and/or
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modify it under the terms of the GNU Lesser General Public License as
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published by the Free Software Foundation; either version 2.1 of the
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License, or (at your option) any later version.
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The GNU C Library is distributed in the hope that it will be useful,
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but WITHOUT ANY WARRANTY; without even the implied warranty of
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MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
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Lesser General Public License for more details.
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You should have received a copy of the GNU Lesser General Public
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License along with the GNU C Library; see the file COPYING.LIB. If not,
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write to the Free Software Foundation, Inc., 59 Temple Place - Suite 330,
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Boston, MA 02111-1307, USA. */
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#include <errno.h>
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#include <setjmp.h>
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#include <signal.h>
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#include <stdbool.h>
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#include <sysdep.h>
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#include <kernel-features.h>
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#include <nptl/pthreadP.h>
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#include "kernel-posix-timers.h"
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#ifdef __NR_timer_create
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/* Helper thread to call the user-provided function. */
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static void *
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timer_sigev_thread (void *arg)
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{
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/* The parent thread has all signals blocked. This is a bit
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surprising for user code, although valid. We unblock all
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signals. */
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sigset_t ss;
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sigemptyset (&ss);
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INTERNAL_SYSCALL_DECL (err);
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INTERNAL_SYSCALL (rt_sigprocmask, err, 4, SIG_SETMASK, &ss, NULL, _NSIG / 8);
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struct timer *tk = (struct timer *) arg;
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/* Call the user-provided function. */
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tk->thrfunc (tk->sival);
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return NULL;
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}
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/* Helper function to support starting threads for SIGEV_THREAD. */
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static void *
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timer_helper_thread (void *arg)
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{
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/* Wait for the SIGTIMER signal and none else. */
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sigset_t ss;
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sigemptyset (&ss);
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sigaddset (&ss, SIGTIMER);
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/* Endless loop of waiting for signals. The loop is only ended when
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the thread is canceled. */
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while (1)
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{
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siginfo_t si;
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/* sigwaitinfo cannot be used here, since it deletes
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SIGCANCEL == SIGTIMER from the set. */
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int oldtype = LIBC_CANCEL_ASYNC ();
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/* XXX The size argument hopefully will have to be changed to the
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real size of the user-level sigset_t. */
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int result = INLINE_SYSCALL (rt_sigtimedwait, 4, &ss, &si, NULL,
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_NSIG / 8);
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LIBC_CANCEL_RESET (oldtype);
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if (result > 0)
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{
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if (si.si_code == SI_TIMER)
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{
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struct timer *tk = (struct timer *) si.si_ptr;
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/* That the signal we are waiting for. */
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pthread_t th;
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(void) pthread_create (&th, &tk->attr, timer_sigev_thread, tk);
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}
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else if (si.si_code == SI_TKILL)
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/* The thread is canceled. */
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pthread_exit (NULL);
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}
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}
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}
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/* Control variable for helper thread creation. */
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pthread_once_t __helper_once attribute_hidden;
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/* TID of the helper thread. */
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pid_t __helper_tid attribute_hidden;
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/* Reset variables so that after a fork a new helper thread gets started. */
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static void
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reset_helper_control (void)
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{
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__helper_once = PTHREAD_ONCE_INIT;
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__helper_tid = 0;
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}
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void
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attribute_hidden
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__start_helper_thread (void)
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{
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/* The helper thread needs only very little resources
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and should go away automatically when canceled. */
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pthread_attr_t attr;
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(void) pthread_attr_init (&attr);
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(void) pthread_attr_setstacksize (&attr, PTHREAD_STACK_MIN);
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/* Block all signals in the helper thread. To do this thoroughly we
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temporarily have to block all signals here. */
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sigset_t ss;
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sigset_t oss;
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sigfillset (&ss);
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INTERNAL_SYSCALL_DECL (err);
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INTERNAL_SYSCALL (rt_sigprocmask, err, 4, SIG_SETMASK, &ss, &oss, _NSIG / 8);
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/* Create the helper thread for this timer. */
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pthread_t th;
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int res = pthread_create (&th, &attr, timer_helper_thread, NULL);
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if (res == 0)
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/* We managed to start the helper thread. */
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__helper_tid = ((struct pthread *) th)->tid;
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/* Restore the signal mask. */
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INTERNAL_SYSCALL (rt_sigprocmask, err, 4, SIG_SETMASK, &oss, NULL,
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_NSIG / 8);
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/* No need for the attribute anymore. */
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(void) pthread_attr_destroy (&attr);
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/* We have to make sure that after fork()ing a new helper thread can
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be created. */
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pthread_atfork (NULL, NULL, reset_helper_control);
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}
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#endif
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#ifndef __ASSUME_POSIX_TIMERS
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# include <nptl/sysdeps/pthread/timer_routines.c>
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#endif
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