| /* Copyright (C) 2006-2018 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 <nptl/pthreadP.h> |
| #include <futex-internal.h> |
| |
| #define DONT_NEED_GAI_MISC_COND 1 |
| |
| #define GAI_MISC_NOTIFY(waitlist) \ |
| do { \ |
| if (*waitlist->counterp > 0 && --*waitlist->counterp == 0) \ |
| futex_wake ((unsigned int *) waitlist->counterp, 1, FUTEX_PRIVATE); \ |
| } while (0) |
| |
| #define GAI_MISC_WAIT(result, futex, timeout, cancel) \ |
| do { \ |
| volatile unsigned int *futexaddr = &futex; \ |
| unsigned int oldval = futex; \ |
| \ |
| if (oldval != 0) \ |
| { \ |
| pthread_mutex_unlock (&__gai_requests_mutex); \ |
| \ |
| int oldtype; \ |
| if (cancel) \ |
| oldtype = LIBC_CANCEL_ASYNC (); \ |
| \ |
| int status; \ |
| do \ |
| { \ |
| status = futex_reltimed_wait ((unsigned int *) futexaddr, oldval, \ |
| timeout, FUTEX_PRIVATE); \ |
| if (status != EAGAIN) \ |
| 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 == EAGAIN); \ |
| \ |
| pthread_mutex_lock (&__gai_requests_mutex); \ |
| } \ |
| } while (0) |
| |
| |
| #define gai_start_notify_thread __gai_start_notify_thread |
| /* For some reason, with clang this define causes a linktime failure |
| building libanl.so. */ |
| #ifndef __clang__ |
| #define gai_create_helper_thread __gai_create_helper_thread |
| #endif |
| |
| extern inline void |
| __gai_start_notify_thread (void) |
| { |
| sigset_t ss; |
| sigemptyset (&ss); |
| int sigerr __attribute__ ((unused)); |
| sigerr = pthread_sigmask (SIG_SETMASK, &ss, NULL); |
| assert_perror (sigerr); |
| } |
| |
| 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); |
| int sigerr __attribute__ ((unused)); |
| sigerr = pthread_sigmask (SIG_SETMASK, &ss, &oss); |
| assert_perror (sigerr); |
| |
| int ret = pthread_create (threadp, &attr, tf, arg); |
| |
| /* Restore the signal mask. */ |
| sigerr = pthread_sigmask (SIG_SETMASK, &oss, NULL); |
| assert_perror (sigerr); |
| |
| (void) pthread_attr_destroy (&attr); |
| return ret; |
| } |
| |
| #include_next <gai_misc.h> |
