X-Git-Url: https://git.saurik.com/apple/libpthread.git/blobdiff_plain/f1a1da6cf65a9d0e6858678f6c259025cf5d27fd..HEAD:/src/pthread_cancelable.c diff --git a/src/pthread_cancelable.c b/src/pthread_cancelable.c index c875451..171f86d 100644 --- a/src/pthread_cancelable.c +++ b/src/pthread_cancelable.c @@ -2,14 +2,14 @@ * Copyright (c) 2000-2013 Apple Inc. All rights reserved. * * @APPLE_LICENSE_HEADER_START@ - * + * * This file contains Original Code and/or Modifications of Original Code * as defined in and that are subject to the Apple Public Source License * Version 2.0 (the 'License'). You may not use this file except in * compliance with the License. Please obtain a copy of the License at * http://www.opensource.apple.com/apsl/ and read it before using this * file. - * + * * The Original Code and all software distributed under the License are * distributed on an 'AS IS' basis, WITHOUT WARRANTY OF ANY KIND, EITHER * EXPRESS OR IMPLIED, AND APPLE HEREBY DISCLAIMS ALL SUCH WARRANTIES, @@ -17,29 +17,29 @@ * FITNESS FOR A PARTICULAR PURPOSE, QUIET ENJOYMENT OR NON-INFRINGEMENT. * Please see the License for the specific language governing rights and * limitations under the License. - * + * * @APPLE_LICENSE_HEADER_END@ */ /* - * Copyright 1996 1995 by Open Software Foundation, Inc. 1997 1996 1995 1994 1993 1992 1991 - * All Rights Reserved - * - * Permission to use, copy, modify, and distribute this software and - * its documentation for any purpose and without fee is hereby granted, - * provided that the above copyright notice appears in all copies and - * that both the copyright notice and this permission notice appear in - * supporting documentation. - * - * OSF DISCLAIMS ALL WARRANTIES WITH REGARD TO THIS SOFTWARE - * INCLUDING ALL IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS - * FOR A PARTICULAR PURPOSE. - * - * IN NO EVENT SHALL OSF BE LIABLE FOR ANY SPECIAL, INDIRECT, OR - * CONSEQUENTIAL DAMAGES OR ANY DAMAGES WHATSOEVER RESULTING FROM - * LOSS OF USE, DATA OR PROFITS, WHETHER IN ACTION OF CONTRACT, - * NEGLIGENCE, OR OTHER TORTIOUS ACTION, ARISING OUT OF OR IN CONNECTION - * WITH THE USE OR PERFORMANCE OF THIS SOFTWARE. - * + * Copyright 1996 1995 by Open Software Foundation, Inc. 1997 1996 1995 1994 1993 1992 1991 + * All Rights Reserved + * + * Permission to use, copy, modify, and distribute this software and + * its documentation for any purpose and without fee is hereby granted, + * provided that the above copyright notice appears in all copies and + * that both the copyright notice and this permission notice appear in + * supporting documentation. + * + * OSF DISCLAIMS ALL WARRANTIES WITH REGARD TO THIS SOFTWARE + * INCLUDING ALL IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS + * FOR A PARTICULAR PURPOSE. + * + * IN NO EVENT SHALL OSF BE LIABLE FOR ANY SPECIAL, INDIRECT, OR + * CONSEQUENTIAL DAMAGES OR ANY DAMAGES WHATSOEVER RESULTING FROM + * LOSS OF USE, DATA OR PROFITS, WHETHER IN ACTION OF CONTRACT, + * NEGLIGENCE, OR OTHER TORTIOUS ACTION, ARISING OUT OF OR IN CONNECTION + * WITH THE USE OR PERFORMANCE OF THIS SOFTWARE. + * */ /* * MkLinux @@ -49,6 +49,7 @@ * POSIX Pthread Library */ +#include "resolver.h" #include "internal.h" #include /* For printf(). */ @@ -59,300 +60,399 @@ #include #include #include +#include #include #include -extern int __unix_conforming; -extern int _pthread_setcancelstate_internal(int state, int *oldstate, int conforming); -extern void _pthread_testcancel(pthread_t thread, int isconforming); -extern int _pthread_cond_wait(pthread_cond_t *cond, - pthread_mutex_t *mutex, - const struct timespec *abstime, - int isRelative, - int isconforming); -extern int __sigwait(const sigset_t *set, int *sig); -extern int __pthread_sigmask(int, const sigset_t *, sigset_t *); -extern int __pthread_markcancel(int); +#ifndef BUILDING_VARIANT /* [ */ -#ifdef VARIANT_CANCELABLE -extern int __semwait_signal(int cond_sem, int mutex_sem, int timeout, int relative, __int64_t tv_sec, __int32_t tv_nsec); -#else -extern int __semwait_signal(int cond_sem, int mutex_sem, int timeout, int relative, __int64_t tv_sec, __int32_t tv_nsec) __asm__("___semwait_signal_nocancel"); -#endif +OS_ALWAYS_INLINE +static inline int +_pthread_update_cancel_state(pthread_t thread, int mask, int state) +{ + uint16_t oldstate, newstate; + os_atomic_rmw_loop(&thread->cancel_state, oldstate, newstate, relaxed, { + newstate = oldstate; + newstate &= ~mask; + newstate |= state; + }); + return oldstate; +} -#ifndef VARIANT_CANCELABLE +/* When a thread exits set the cancellation state to DISABLE and DEFERRED */ +void +_pthread_setcancelstate_exit(pthread_t thread, void *value_ptr) +{ + _pthread_update_cancel_state(thread, + _PTHREAD_CANCEL_STATE_MASK | _PTHREAD_CANCEL_TYPE_MASK, + PTHREAD_CANCEL_DISABLE | PTHREAD_CANCEL_DEFERRED | + _PTHREAD_CANCEL_EXITING); +} /* * Cancel a thread */ +PTHREAD_NOEXPORT_VARIANT int pthread_cancel(pthread_t thread) { -#if __DARWIN_UNIX03 - if (__unix_conforming == 0) - __unix_conforming = 1; -#endif /* __DARWIN_UNIX03 */ - - if (_pthread_lookup_thread(thread, NULL, 0) != 0) + if (!_pthread_is_valid(thread, NULL)) { return(ESRCH); + } /* if the thread is a workqueue thread, then return error */ if (thread->wqthread != 0) { return(ENOTSUP); } -#if __DARWIN_UNIX03 - int state; - - LOCK(thread->lock); - state = thread->cancel_state |= _PTHREAD_CANCEL_PENDING; - UNLOCK(thread->lock); - if (state & PTHREAD_CANCEL_ENABLE) - __pthread_markcancel(_pthread_kernel_thread(thread)); -#else /* __DARWIN_UNIX03 */ - thread->cancel_state |= _PTHREAD_CANCEL_PENDING; -#endif /* __DARWIN_UNIX03 */ + int state = os_atomic_or(&thread->cancel_state, _PTHREAD_CANCEL_PENDING, relaxed); + if (state & PTHREAD_CANCEL_ENABLE) { + mach_port_t kport = _pthread_tsd_slot(thread, MACH_THREAD_SELF); + if (kport) __pthread_markcancel(kport); + } return (0); } -void -pthread_testcancel(void) -{ - pthread_t self = pthread_self(); - -#if __DARWIN_UNIX03 - if (__unix_conforming == 0) - __unix_conforming = 1; - _pthread_testcancel(self, 1); -#else /* __DARWIN_UNIX03 */ - _pthread_testcancel(self, 0); -#endif /* __DARWIN_UNIX03 */ -} - /* * Query/update the cancelability 'state' of a thread */ +PTHREAD_NOEXPORT_VARIANT int -pthread_setcancelstate(int state, int *oldstate) +pthread_setcancelstate(int state, int *oldstateptr) { -#if __DARWIN_UNIX03 - if (__unix_conforming == 0) { - __unix_conforming = 1; + pthread_t self = pthread_self(); + + _pthread_validate_signature(self); + + switch (state) { + case PTHREAD_CANCEL_ENABLE: + __pthread_canceled(1); + break; + case PTHREAD_CANCEL_DISABLE: + __pthread_canceled(2); + break; + default: + return EINVAL; } - return (_pthread_setcancelstate_internal(state, oldstate, 1)); -#else /* __DARWIN_UNIX03 */ - return (_pthread_setcancelstate_internal(state, oldstate, 0)); -#endif /* __DARWIN_UNIX03 */ + + int oldstate = _pthread_update_cancel_state(self, _PTHREAD_CANCEL_STATE_MASK, state); + if (oldstateptr) { + *oldstateptr = oldstate & _PTHREAD_CANCEL_STATE_MASK; + } + return 0; } /* * Query/update the cancelability 'type' of a thread */ +PTHREAD_NOEXPORT_VARIANT int pthread_setcanceltype(int type, int *oldtype) { - pthread_t self; + pthread_t self = pthread_self(); -#if __DARWIN_UNIX03 - if (__unix_conforming == 0) - __unix_conforming = 1; -#endif /* __DARWIN_UNIX03 */ + _pthread_validate_signature(self); if ((type != PTHREAD_CANCEL_DEFERRED) && (type != PTHREAD_CANCEL_ASYNCHRONOUS)) return EINVAL; - self = pthread_self(); - LOCK(self->lock); - if (oldtype) - *oldtype = self->cancel_state & _PTHREAD_CANCEL_TYPE_MASK; - self->cancel_state &= ~_PTHREAD_CANCEL_TYPE_MASK; - self->cancel_state |= type; - UNLOCK(self->lock); -#if !__DARWIN_UNIX03 - _pthread_testcancel(self, 0); /* See if we need to 'die' now... */ -#endif /* __DARWIN_UNIX03 */ + int oldstate = _pthread_update_cancel_state(self, _PTHREAD_CANCEL_TYPE_MASK, type); + if (oldtype) { + *oldtype = oldstate & _PTHREAD_CANCEL_TYPE_MASK; + } return (0); } + +OS_ALWAYS_INLINE +static inline bool +_pthread_is_canceled(pthread_t thread) +{ + const int flags = (PTHREAD_CANCEL_ENABLE|_PTHREAD_CANCEL_PENDING); + int state = os_atomic_load(&thread->cancel_state, seq_cst); + return (state & flags) == flags; +} + +OS_ALWAYS_INLINE +static inline void * +_pthread_get_exit_value(pthread_t thread) +{ + if (os_unlikely(_pthread_is_canceled(thread))) { + return PTHREAD_CANCELED; + } + return thread->tl_exit_value; +} + +void +pthread_testcancel(void) +{ + pthread_t self = pthread_self(); + if (os_unlikely(_pthread_is_canceled(self))) { + _pthread_validate_signature(self); + // 4597450: begin + self->canceled = true; + // 4597450: end + pthread_exit(PTHREAD_CANCELED); + } +} + +void +_pthread_markcancel_if_canceled(pthread_t thread, mach_port_t kport) +{ + if (os_unlikely(_pthread_is_canceled(thread))) { + __pthread_markcancel(kport); + } +} + +void +_pthread_exit_if_canceled(int error) +{ + if ((error & 0xff) == EINTR && __pthread_canceled(0) == 0) { + pthread_t self = pthread_self(); + + _pthread_validate_signature(self); + self->cancel_error = error; + self->canceled = true; + pthread_exit(PTHREAD_CANCELED); + } +} + int pthread_sigmask(int how, const sigset_t * set, sigset_t * oset) { -#if __DARWIN_UNIX03 int err = 0; if (__pthread_sigmask(how, set, oset) == -1) { err = errno; } return(err); -#else /* __DARWIN_UNIX03 */ - return(__pthread_sigmask(how, set, oset)); -#endif /* __DARWIN_UNIX03 */ } -#endif /* VARIANT_CANCELABLE */ - -#if __DARWIN_UNIX03 +// called with _pthread_list_lock held +semaphore_t +_pthread_joiner_prepost_wake(pthread_t thread) +{ + pthread_join_context_t ctx = thread->tl_join_ctx; + semaphore_t sema = MACH_PORT_NULL; + + if (thread->tl_joinable) { + sema = ctx->custom_stack_sema; + thread->tl_joinable = false; + } else { + ctx->detached = true; + thread->tl_join_ctx = NULL; + } + if (ctx->value_ptr) *ctx->value_ptr = _pthread_get_exit_value(thread); + return sema; +} -static void -__posix_join_cleanup(void *arg) +static inline bool +_pthread_joiner_abort_wait(pthread_t thread, pthread_join_context_t ctx) { - pthread_t thread = (pthread_t)arg; + bool aborted = false; - LOCK(thread->lock); - /* leave another thread to join */ - thread->joiner = (struct _pthread *)NULL; - UNLOCK(thread->lock); + _pthread_lock_lock(&_pthread_list_lock); + if (!ctx->detached && thread->tl_exit_gate != MACH_PORT_DEAD) { + /* + * _pthread_joiner_prepost_wake() didn't happen + * allow another thread to join + */ + PTHREAD_DEBUG_ASSERT(thread->tl_join_ctx == ctx); + thread->tl_join_ctx = NULL; + thread->tl_exit_gate = MACH_PORT_NULL; + aborted = true; + } + _pthread_lock_unlock(&_pthread_list_lock); + return aborted; } -#endif /* __DARWIN_UNIX03 */ - -/* - * Wait for a thread to terminate and obtain its exit value. - */ -int -pthread_join(pthread_t thread, - void **value_ptr) +static int +_pthread_joiner_wait(pthread_t thread, pthread_join_context_t ctx, + pthread_conformance_t conforming) { - int res = 0; - pthread_t self = pthread_self(); - mach_port_t kthport; - int conforming = 0; -#if !__DARWIN_UNIX03 - kern_return_t kern_res; -#endif + uint32_t *exit_gate = &thread->tl_exit_gate; + int ulock_op = UL_UNFAIR_LOCK | ULF_NO_ERRNO; + + if (conforming == PTHREAD_CONFORM_UNIX03_CANCELABLE) { + ulock_op |= ULF_WAIT_CANCEL_POINT; + } -#if __DARWIN_UNIX03 - if (__unix_conforming == 0) - __unix_conforming = 1; + for (;;) { + uint32_t cur = os_atomic_load(exit_gate, acquire); + if (cur == MACH_PORT_DEAD) { + break; + } + if (os_unlikely(cur != ctx->kport)) { + PTHREAD_CLIENT_CRASH(cur, "pthread_join() state corruption"); + } + int ret = __ulock_wait(ulock_op, exit_gate, ctx->kport, 0); + switch (-ret) { + case 0: + case EFAULT: + break; + case EINTR: + /* + * POSIX says: + * + * As specified, either the pthread_join() call is canceled, or it + * succeeds, but not both. The difference is obvious to the + * application, since either a cancellation handler is run or + * pthread_join() returns. + * + * When __ulock_wait() returns EINTR, we check if we have been + * canceled, and if we have, we try to abort the wait. + * + * If we can't, it means the other thread finished the join while we + * were being canceled and commited the waiter to return from + * pthread_join(). Returning from the join then takes precedence + * over the cancelation which will be acted upon at the next + * cancelation point. + */ + if (os_unlikely(conforming == PTHREAD_CONFORM_UNIX03_CANCELABLE && + _pthread_is_canceled(ctx->waiter))) { + if (_pthread_joiner_abort_wait(thread, ctx)) { + ctx->waiter->canceled = true; + pthread_exit(PTHREAD_CANCELED); + } + } + break; + } + } -#ifdef VARIANT_CANCELABLE - _pthread_testcancel(self, 1); -#endif /* VARIANT_CANCELABLE */ -#endif /* __DARWIN_UNIX03 */ + bool cleanup = false; - if ((res = _pthread_lookup_thread(thread, &kthport, 1)) != 0) - return(res); + _pthread_lock_lock(&_pthread_list_lock); + // If pthread_detach() was called, we can't safely dereference the thread, + // else, decide who gets to deallocate the thread (see _pthread_terminate). + if (!ctx->detached) { + PTHREAD_DEBUG_ASSERT(thread->tl_join_ctx == ctx); + thread->tl_join_ctx = NULL; + cleanup = thread->tl_joiner_cleans_up; + } + _pthread_lock_unlock(&_pthread_list_lock); + + if (cleanup) { + _pthread_deallocate(thread, false); + } + return 0; +} + +OS_NOINLINE +int +_pthread_join(pthread_t thread, void **value_ptr, pthread_conformance_t conforming) +{ + pthread_t self = pthread_self(); + pthread_join_context_s ctx = { + .waiter = self, + .value_ptr = value_ptr, + .kport = MACH_PORT_NULL, + .custom_stack_sema = MACH_PORT_NULL, + }; + int res = 0; + kern_return_t kr; - if (thread->sig == _PTHREAD_SIG) { - semaphore_t death = SEMAPHORE_NULL; /* in case we need it */ - semaphore_t joinsem = SEMAPHORE_NULL; + if (!_pthread_validate_thread_and_list_lock(thread)) { + return ESRCH; + } - if (thread->joiner_notify == SEMAPHORE_NULL) { - death = (semaphore_t)os_get_cached_semaphore(); + _pthread_validate_signature(self); + + if (!thread->tl_joinable || (thread->tl_join_ctx != NULL)) { + res = EINVAL; + } else if (thread == self || + (self->tl_join_ctx && self->tl_join_ctx->waiter == thread)) { + res = EDEADLK; + } else if (thread->tl_exit_gate == MACH_PORT_DEAD) { + TAILQ_REMOVE(&__pthread_head, thread, tl_plist); + PTHREAD_DEBUG_ASSERT(thread->tl_joiner_cleans_up); + thread->tl_joinable = false; + if (value_ptr) *value_ptr = _pthread_get_exit_value(thread); + } else { + ctx.kport = _pthread_tsd_slot(thread, MACH_THREAD_SELF); + thread->tl_exit_gate = ctx.kport; + thread->tl_join_ctx = &ctx; + if (thread->tl_has_custom_stack) { + ctx.custom_stack_sema = (semaphore_t)os_get_cached_semaphore(); } + } + _pthread_lock_unlock(&_pthread_list_lock); - LOCK(thread->lock); - if ((thread->detached & PTHREAD_CREATE_JOINABLE) && - (thread->joiner == NULL)) { - PTHREAD_ASSERT(_pthread_kernel_thread(thread) == kthport); - if (thread != self && (self == NULL || self->joiner != thread)) { - if (thread->joiner_notify == SEMAPHORE_NULL) { - thread->joiner_notify = death; - death = SEMAPHORE_NULL; - } - joinsem = thread->joiner_notify; - thread->joiner = self; - UNLOCK(thread->lock); - - if (death != SEMAPHORE_NULL) { - os_put_cached_semaphore((os_semaphore_t)death); - death = SEMAPHORE_NULL; - } -#if __DARWIN_UNIX03 - /* Wait for it to signal... */ - pthread_cleanup_push(__posix_join_cleanup, (void *)thread); - do { - res = __semwait_signal(joinsem, 0, 0, 0, (int64_t)0, (int32_t)0); - } while ((res < 0) && (errno == EINTR)); - pthread_cleanup_pop(0); -#else /* __DARWIN_UNIX03 */ - /* Wait for it to signal... */ - do { - kern_res = semaphore_wait(joinsem); - } while (kern_res != KERN_SUCCESS); -#endif /* __DARWIN_UNIX03 */ - - os_put_cached_semaphore((os_semaphore_t)joinsem); - res = _pthread_join_cleanup(thread, value_ptr, conforming); - } else { - UNLOCK(thread->lock); - res = EDEADLK; - } + if (res == 0) { + if (ctx.kport == MACH_PORT_NULL) { + _pthread_deallocate(thread, false); } else { - UNLOCK(thread->lock); - res = EINVAL; + res = _pthread_joiner_wait(thread, &ctx, conforming); } - if (death != SEMAPHORE_NULL) { - os_put_cached_semaphore((os_semaphore_t)death); - } - return res; } - return ESRCH; + if (res == 0 && ctx.custom_stack_sema && !ctx.detached) { + // threads with a custom stack need to make sure _pthread_terminate + // returned before the joiner is unblocked, the joiner may quickly + // deallocate the stack with rather dire consequences. + // + // When we reach this point we know the pthread_join has to succeed + // so this can't be a cancelation point. + do { + kr = __semwait_signal_nocancel(ctx.custom_stack_sema, 0, 0, 0, 0, 0); + } while (kr != KERN_SUCCESS); + } + if (ctx.custom_stack_sema) { + os_put_cached_semaphore(ctx.custom_stack_sema); + } + return res; } -int -pthread_cond_wait(pthread_cond_t *cond, - pthread_mutex_t *mutex) -{ - int conforming; -#if __DARWIN_UNIX03 - - if (__unix_conforming == 0) - __unix_conforming = 1; +#endif /* !BUILDING_VARIANT ] */ +static inline pthread_conformance_t +_pthread_conformance(void) +{ #ifdef VARIANT_CANCELABLE - conforming = 1; + return PTHREAD_CONFORM_UNIX03_CANCELABLE; #else /* !VARIANT_CANCELABLE */ - conforming = -1; -#endif /* VARIANT_CANCELABLE */ -#else /* __DARWIN_UNIX03 */ - conforming = 0; -#endif /* __DARWIN_UNIX03 */ - return (_pthread_cond_wait(cond, mutex, (struct timespec *)NULL, 0, conforming)); + return PTHREAD_CONFORM_UNIX03_NOCANCEL; +#endif } -int -pthread_cond_timedwait(pthread_cond_t *cond, - pthread_mutex_t *mutex, - const struct timespec *abstime) +static inline void +_pthread_testcancel_if_cancelable_variant(void) { - int conforming; -#if __DARWIN_UNIX03 - if (__unix_conforming == 0) - __unix_conforming = 1; - #ifdef VARIANT_CANCELABLE - conforming = 1; -#else /* !VARIANT_CANCELABLE */ - conforming = -1; -#endif /* VARIANT_CANCELABLE */ -#else /* __DARWIN_UNIX03 */ - conforming = 0; -#endif /* __DARWIN_UNIX03 */ + pthread_testcancel(); +#endif +} + +int +pthread_join(pthread_t thread, void **value_ptr) +{ + _pthread_testcancel_if_cancelable_variant(); + return _pthread_join(thread, value_ptr, _pthread_conformance()); +} + +int +pthread_cond_wait(pthread_cond_t *cond, pthread_mutex_t *mutex) +{ + return _pthread_cond_wait(cond, mutex, NULL, 0, _pthread_conformance()); +} - return (_pthread_cond_wait(cond, mutex, abstime, 0, conforming)); +int +pthread_cond_timedwait(pthread_cond_t *cond, pthread_mutex_t *mutex, + const struct timespec *abstime) +{ + return _pthread_cond_wait(cond, mutex, abstime, 0, _pthread_conformance()); } int sigwait(const sigset_t * set, int * sig) { -#if __DARWIN_UNIX03 int err = 0; - if (__unix_conforming == 0) - __unix_conforming = 1; - -#ifdef VARIANT_CANCELABLE - _pthread_testcancel(pthread_self(), 1); -#endif /* VARIANT_CANCELABLE */ + _pthread_testcancel_if_cancelable_variant(); if (__sigwait(set, sig) == -1) { err = errno; -#ifdef VARIANT_CANCELABLE - _pthread_testcancel(pthread_self(), 1); -#endif /* VARIANT_CANCELABLE */ - - /* + _pthread_testcancel_if_cancelable_variant(); + + /* * EINTR that isn't a result of pthread_cancel() * is translated to 0. */ @@ -361,17 +461,5 @@ sigwait(const sigset_t * set, int * sig) } } return(err); -#else /* __DARWIN_UNIX03 */ - if (__sigwait(set, sig) == -1) { - /* - * EINTR that isn't a result of pthread_cancel() - * is translated to 0. - */ - if (errno != EINTR) { - return -1; - } - } - - return 0; -#endif /* __DARWIN_UNIX03 */ } +