/* Copyright (C) 2006-2014 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; if not, see <http://www.gnu.org/licenses/>. */ /* We define a special synchronization primitive for AIO. POSIX conditional variables would be ideal but the pthread_cond_*wait operations do not return on EINTR. This is a requirement for correct aio_suspend and lio_listio implementations. */ #include <assert.h> #include <signal.h> #include <pthreadP.h> #include <lowlevellock.h> #define DONT_NEED_GAI_MISC_COND 1 #define GAI_MISC_NOTIFY(waitlist) \ do { \ if (*waitlist->counterp > 0 && --*waitlist->counterp == 0) \ lll_futex_wake (waitlist->counterp, 1, LLL_PRIVATE); \ } while (0) #define GAI_MISC_WAIT(result, futex, timeout, cancel) \ do { \ volatile int *futexaddr = &futex; \ int oldval = futex; \ \ if (oldval != 0) \ { \ pthread_mutex_unlock (&__gai_requests_mutex); \ \ int oldtype; \ if (cancel) \ oldtype = LIBC_CANCEL_ASYNC (); \ \ int status; \ do \ { \ status = lll_futex_timed_wait (futexaddr, oldval, timeout, \ LLL_PRIVATE); \ if (status != -EWOULDBLOCK) \ break; \ \ oldval = *futexaddr; \ } \ while (oldval != 0); \ \ if (cancel) \ LIBC_CANCEL_RESET (oldtype); \ \ if (status == -EINTR) \ result = EINTR; \ else if (status == -ETIMEDOUT) \ result = EAGAIN; \ else \ assert (status == 0 || status == -EWOULDBLOCK); \ \ pthread_mutex_lock (&__gai_requests_mutex); \ } \ } while (0) #define gai_start_notify_thread __gai_start_notify_thread #define gai_create_helper_thread __gai_create_helper_thread extern inline void __gai_start_notify_thread (void) { sigset_t ss; sigemptyset (&ss); INTERNAL_SYSCALL_DECL (err); INTERNAL_SYSCALL (rt_sigprocmask, err, 4, SIG_SETMASK, &ss, NULL, _NSIG / 8); } extern inline int __gai_create_helper_thread (pthread_t *threadp, void *(*tf) (void *), void *arg) { pthread_attr_t attr; /* Make sure the thread is created detached. */ pthread_attr_init (&attr); pthread_attr_setdetachstate (&attr, PTHREAD_CREATE_DETACHED); /* The helper thread needs only very little resources. */ (void) pthread_attr_setstacksize (&attr, __pthread_get_minstack (&attr) + 4 * PTHREAD_STACK_MIN); /* Block all signals in the helper thread. To do this thoroughly we temporarily have to block all signals here. */ sigset_t ss; sigset_t oss; sigfillset (&ss); INTERNAL_SYSCALL_DECL (err); INTERNAL_SYSCALL (rt_sigprocmask, err, 4, SIG_SETMASK, &ss, &oss, _NSIG / 8); int ret = pthread_create (threadp, &attr, tf, arg); /* Restore the signal mask. */ INTERNAL_SYSCALL (rt_sigprocmask, err, 4, SIG_SETMASK, &oss, NULL, _NSIG / 8); (void) pthread_attr_destroy (&attr); return ret; } #include_next <gai_misc.h>