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Diffstat (limited to 'sysdeps/nptl/gai_misc.h')
| -rw-r--r-- | sysdeps/nptl/gai_misc.h | 121 |
1 files changed, 121 insertions, 0 deletions
diff --git a/sysdeps/nptl/gai_misc.h b/sysdeps/nptl/gai_misc.h new file mode 100644 index 0000000000..946275ed75 --- /dev/null +++ b/sysdeps/nptl/gai_misc.h @@ -0,0 +1,121 @@ +/* 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> |