diff options
Diffstat (limited to 'libpthread/nptl/sysdeps/unix/sysv/linux/timer_routines.c')
-rw-r--r-- | libpthread/nptl/sysdeps/unix/sysv/linux/timer_routines.c | 164 |
1 files changed, 164 insertions, 0 deletions
diff --git a/libpthread/nptl/sysdeps/unix/sysv/linux/timer_routines.c b/libpthread/nptl/sysdeps/unix/sysv/linux/timer_routines.c new file mode 100644 index 000000000..0ddfe8a51 --- /dev/null +++ b/libpthread/nptl/sysdeps/unix/sysv/linux/timer_routines.c @@ -0,0 +1,164 @@ +/* Copyright (C) 2003, 2004, 2005 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, + write to the Free Software Foundation, Inc., 59 Temple Place - Suite 330, + Boston, MA 02111-1307, USA. */ + +#include <errno.h> +#include <setjmp.h> +#include <signal.h> +#include <stdbool.h> +#include <sysdep.h> +#include <bits/kernel-features.h> +#include <pthreadP.h> +#include "kernel-posix-timers.h" + + +#ifdef __NR_timer_create +/* Helper thread to call the user-provided function. */ +static void * +timer_sigev_thread (void *arg) +{ + /* The parent thread has all signals blocked. This is a bit + surprising for user code, although valid. We unblock all + signals. */ + sigset_t ss; + sigemptyset (&ss); + INTERNAL_SYSCALL_DECL (err); + INTERNAL_SYSCALL (rt_sigprocmask, err, 4, SIG_SETMASK, &ss, NULL, _NSIG / 8); + + struct timer *tk = (struct timer *) arg; + + /* Call the user-provided function. */ + tk->thrfunc (tk->sival); + + return NULL; +} + + +/* Helper function to support starting threads for SIGEV_THREAD. */ +static void * +timer_helper_thread (void *arg) +{ + /* Wait for the SIGTIMER signal, allowing the setXid signal, and + none else. */ + sigset_t ss; + sigemptyset (&ss); + __sigaddset (&ss, SIGTIMER); +#ifdef SIGSETXID + __sigaddset (&ss, SIGSETXID); +#endif + + /* Endless loop of waiting for signals. The loop is only ended when + the thread is canceled. */ + while (1) + { + siginfo_t si; + + /* sigwaitinfo cannot be used here, since it deletes + SIGCANCEL == SIGTIMER from the set. */ + + int oldtype = LIBC_CANCEL_ASYNC (); + + /* XXX The size argument hopefully will have to be changed to the + real size of the user-level sigset_t. */ + int result = INLINE_SYSCALL (rt_sigtimedwait, 4, &ss, &si, NULL, + _NSIG / 8); + + LIBC_CANCEL_RESET (oldtype); + + if (result > 0) + { + if (si.si_code == SI_TIMER) + { + struct timer *tk = (struct timer *) si.si_ptr; + + /* That the signal we are waiting for. */ + pthread_t th; + (void) pthread_create (&th, &tk->attr, timer_sigev_thread, tk); + } + else if (si.si_code == SI_TKILL) + /* The thread is canceled. */ + pthread_exit (NULL); + } + } +} + + +/* Control variable for helper thread creation. */ +pthread_once_t __helper_once attribute_hidden; + + +/* TID of the helper thread. */ +pid_t __helper_tid attribute_hidden; + + +/* Reset variables so that after a fork a new helper thread gets started. */ +static void +reset_helper_control (void) +{ + __helper_once = PTHREAD_ONCE_INIT; + __helper_tid = 0; +} + + +void +attribute_hidden +__start_helper_thread (void) +{ + /* The helper thread needs only very little resources + and should go away automatically when canceled. */ + pthread_attr_t attr; + (void) pthread_attr_init (&attr); + (void) pthread_attr_setstacksize (&attr, PTHREAD_STACK_MIN); + + /* Block all signals in the helper thread but SIGSETXID. To do this + thoroughly we temporarily have to block all signals here. The + helper can lose wakeups if SIGCANCEL is not blocked throughout, + but sigfillset omits it. So, we add it back explicitly here. */ + sigset_t ss; + sigset_t oss; + sigfillset (&ss); + __sigaddset (&ss, SIGCANCEL); +#ifdef SIGSETXID + __sigdelset (&ss, SIGSETXID); +#endif + INTERNAL_SYSCALL_DECL (err); + INTERNAL_SYSCALL (rt_sigprocmask, err, 4, SIG_SETMASK, &ss, &oss, _NSIG / 8); + + /* Create the helper thread for this timer. */ + pthread_t th; + int res = pthread_create (&th, &attr, timer_helper_thread, NULL); + if (res == 0) + /* We managed to start the helper thread. */ + __helper_tid = ((struct pthread *) th)->tid; + + /* Restore the signal mask. */ + INTERNAL_SYSCALL (rt_sigprocmask, err, 4, SIG_SETMASK, &oss, NULL, + _NSIG / 8); + + /* No need for the attribute anymore. */ + (void) pthread_attr_destroy (&attr); + + /* We have to make sure that after fork()ing a new helper thread can + be created. */ + pthread_atfork (NULL, NULL, reset_helper_control); +} +#endif + +#ifndef __ASSUME_POSIX_TIMERS +# include <nptl/sysdeps/pthread/timer_routines.c> +#endif |