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Diffstat (limited to 'libevent/evthread-internal.h')
| -rw-r--r-- | libevent/evthread-internal.h | 406 |
1 files changed, 406 insertions, 0 deletions
diff --git a/libevent/evthread-internal.h b/libevent/evthread-internal.h new file mode 100644 index 0000000..83e409f --- /dev/null +++ b/libevent/evthread-internal.h @@ -0,0 +1,406 @@ +/* + * Copyright (c) 2008-2012 Niels Provos, Nick Mathewson + * + * Redistribution and use in source and binary forms, with or without + * modification, are permitted provided that the following conditions + * are met: + * 1. Redistributions of source code must retain the above copyright + * notice, this list of conditions and the following disclaimer. + * 2. Redistributions in binary form must reproduce the above copyright + * notice, this list of conditions and the following disclaimer in the + * documentation and/or other materials provided with the distribution. + * 3. The name of the author may not be used to endorse or promote products + * derived from this software without specific prior written permission. + * + * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR + * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES + * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. + * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, + * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT + * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, + * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY + * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT + * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF + * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. + */ +#ifndef EVTHREAD_INTERNAL_H_INCLUDED_ +#define EVTHREAD_INTERNAL_H_INCLUDED_ + +#ifdef __cplusplus +extern "C" { +#endif + +#include "event2/event-config.h" +#include "evconfig-private.h" + +#include "event2/thread.h" +#include "util-internal.h" + +struct event_base; + +#if !defined(_WIN32) && !defined(__CYGWIN__) +/* On Windows, the way we currently make DLLs, it's not allowed for us to + * have shared global structures. Thus, we only do the direct-call-to-function + * code path if we know that the local shared library system supports it. + */ +#define EVTHREAD_EXPOSE_STRUCTS +#endif + +#if ! defined(EVENT__DISABLE_THREAD_SUPPORT) && defined(EVTHREAD_EXPOSE_STRUCTS) +/* Global function pointers to lock-related functions. NULL if locking isn't + enabled. */ +EVENT2_EXPORT_SYMBOL +extern struct evthread_lock_callbacks evthread_lock_fns_; +EVENT2_EXPORT_SYMBOL +extern struct evthread_condition_callbacks evthread_cond_fns_; +extern unsigned long (*evthread_id_fn_)(void); +EVENT2_EXPORT_SYMBOL +extern int evthread_lock_debugging_enabled_; + +/** Return the ID of the current thread, or 1 if threading isn't enabled. */ +#define EVTHREAD_GET_ID() \ + (evthread_id_fn_ ? evthread_id_fn_() : 1) + +/** Return true iff we're in the thread that is currently (or most recently) + * running a given event_base's loop. Requires lock. */ +#define EVBASE_IN_THREAD(base) \ + (evthread_id_fn_ == NULL || \ + (base)->th_owner_id == evthread_id_fn_()) + +/** Return true iff we need to notify the base's main thread about changes to + * its state, because it's currently running the main loop in another + * thread. Requires lock. */ +#define EVBASE_NEED_NOTIFY(base) \ + (evthread_id_fn_ != NULL && \ + (base)->running_loop && \ + (base)->th_owner_id != evthread_id_fn_()) + +/** Allocate a new lock, and store it in lockvar, a void*. Sets lockvar to + NULL if locking is not enabled. */ +#define EVTHREAD_ALLOC_LOCK(lockvar, locktype) \ + ((lockvar) = evthread_lock_fns_.alloc ? \ + evthread_lock_fns_.alloc(locktype) : NULL) + +/** Free a given lock, if it is present and locking is enabled. */ +#define EVTHREAD_FREE_LOCK(lockvar, locktype) \ + do { \ + void *lock_tmp_ = (lockvar); \ + if (lock_tmp_ && evthread_lock_fns_.free) \ + evthread_lock_fns_.free(lock_tmp_, (locktype)); \ + } while (0) + +/** Acquire a lock. */ +#define EVLOCK_LOCK(lockvar,mode) \ + do { \ + if (lockvar) \ + evthread_lock_fns_.lock(mode, lockvar); \ + } while (0) + +/** Release a lock */ +#define EVLOCK_UNLOCK(lockvar,mode) \ + do { \ + if (lockvar) \ + evthread_lock_fns_.unlock(mode, lockvar); \ + } while (0) + +/** Helper: put lockvar1 and lockvar2 into pointerwise ascending order. */ +#define EVLOCK_SORTLOCKS_(lockvar1, lockvar2) \ + do { \ + if (lockvar1 && lockvar2 && lockvar1 > lockvar2) { \ + void *tmp = lockvar1; \ + lockvar1 = lockvar2; \ + lockvar2 = tmp; \ + } \ + } while (0) + +/** Lock an event_base, if it is set up for locking. Acquires the lock + in the base structure whose field is named 'lockvar'. */ +#define EVBASE_ACQUIRE_LOCK(base, lockvar) do { \ + EVLOCK_LOCK((base)->lockvar, 0); \ + } while (0) + +/** Unlock an event_base, if it is set up for locking. */ +#define EVBASE_RELEASE_LOCK(base, lockvar) do { \ + EVLOCK_UNLOCK((base)->lockvar, 0); \ + } while (0) + +/** If lock debugging is enabled, and lock is non-null, assert that 'lock' is + * locked and held by us. */ +#define EVLOCK_ASSERT_LOCKED(lock) \ + do { \ + if ((lock) && evthread_lock_debugging_enabled_) { \ + EVUTIL_ASSERT(evthread_is_debug_lock_held_(lock)); \ + } \ + } while (0) + +/** Try to grab the lock for 'lockvar' without blocking, and return 1 if we + * manage to get it. */ +static inline int EVLOCK_TRY_LOCK_(void *lock); +static inline int +EVLOCK_TRY_LOCK_(void *lock) +{ + if (lock && evthread_lock_fns_.lock) { + int r = evthread_lock_fns_.lock(EVTHREAD_TRY, lock); + return !r; + } else { + /* Locking is disabled either globally or for this thing; + * of course we count as having the lock. */ + return 1; + } +} + +/** Allocate a new condition variable and store it in the void *, condvar */ +#define EVTHREAD_ALLOC_COND(condvar) \ + do { \ + (condvar) = evthread_cond_fns_.alloc_condition ? \ + evthread_cond_fns_.alloc_condition(0) : NULL; \ + } while (0) +/** Deallocate and free a condition variable in condvar */ +#define EVTHREAD_FREE_COND(cond) \ + do { \ + if (cond) \ + evthread_cond_fns_.free_condition((cond)); \ + } while (0) +/** Signal one thread waiting on cond */ +#define EVTHREAD_COND_SIGNAL(cond) \ + ( (cond) ? evthread_cond_fns_.signal_condition((cond), 0) : 0 ) +/** Signal all threads waiting on cond */ +#define EVTHREAD_COND_BROADCAST(cond) \ + ( (cond) ? evthread_cond_fns_.signal_condition((cond), 1) : 0 ) +/** Wait until the condition 'cond' is signalled. Must be called while + * holding 'lock'. The lock will be released until the condition is + * signalled, at which point it will be acquired again. Returns 0 for + * success, -1 for failure. */ +#define EVTHREAD_COND_WAIT(cond, lock) \ + ( (cond) ? evthread_cond_fns_.wait_condition((cond), (lock), NULL) : 0 ) +/** As EVTHREAD_COND_WAIT, but gives up after 'tv' has elapsed. Returns 1 + * on timeout. */ +#define EVTHREAD_COND_WAIT_TIMED(cond, lock, tv) \ + ( (cond) ? evthread_cond_fns_.wait_condition((cond), (lock), (tv)) : 0 ) + +/** True iff locking functions have been configured. */ +#define EVTHREAD_LOCKING_ENABLED() \ + (evthread_lock_fns_.lock != NULL) + +#elif ! defined(EVENT__DISABLE_THREAD_SUPPORT) + +unsigned long evthreadimpl_get_id_(void); +EVENT2_EXPORT_SYMBOL +int evthreadimpl_is_lock_debugging_enabled_(void); +EVENT2_EXPORT_SYMBOL +void *evthreadimpl_lock_alloc_(unsigned locktype); +EVENT2_EXPORT_SYMBOL +void evthreadimpl_lock_free_(void *lock, unsigned locktype); +EVENT2_EXPORT_SYMBOL +int evthreadimpl_lock_lock_(unsigned mode, void *lock); +EVENT2_EXPORT_SYMBOL +int evthreadimpl_lock_unlock_(unsigned mode, void *lock); +EVENT2_EXPORT_SYMBOL +void *evthreadimpl_cond_alloc_(unsigned condtype); +EVENT2_EXPORT_SYMBOL +void evthreadimpl_cond_free_(void *cond); +EVENT2_EXPORT_SYMBOL +int evthreadimpl_cond_signal_(void *cond, int broadcast); +EVENT2_EXPORT_SYMBOL +int evthreadimpl_cond_wait_(void *cond, void *lock, const struct timeval *tv); +int evthreadimpl_locking_enabled_(void); + +#define EVTHREAD_GET_ID() evthreadimpl_get_id_() +#define EVBASE_IN_THREAD(base) \ + ((base)->th_owner_id == evthreadimpl_get_id_()) +#define EVBASE_NEED_NOTIFY(base) \ + ((base)->running_loop && \ + ((base)->th_owner_id != evthreadimpl_get_id_())) + +#define EVTHREAD_ALLOC_LOCK(lockvar, locktype) \ + ((lockvar) = evthreadimpl_lock_alloc_(locktype)) + +#define EVTHREAD_FREE_LOCK(lockvar, locktype) \ + do { \ + void *lock_tmp_ = (lockvar); \ + if (lock_tmp_) \ + evthreadimpl_lock_free_(lock_tmp_, (locktype)); \ + } while (0) + +/** Acquire a lock. */ +#define EVLOCK_LOCK(lockvar,mode) \ + do { \ + if (lockvar) \ + evthreadimpl_lock_lock_(mode, lockvar); \ + } while (0) + +/** Release a lock */ +#define EVLOCK_UNLOCK(lockvar,mode) \ + do { \ + if (lockvar) \ + evthreadimpl_lock_unlock_(mode, lockvar); \ + } while (0) + +/** Lock an event_base, if it is set up for locking. Acquires the lock + in the base structure whose field is named 'lockvar'. */ +#define EVBASE_ACQUIRE_LOCK(base, lockvar) do { \ + EVLOCK_LOCK((base)->lockvar, 0); \ + } while (0) + +/** Unlock an event_base, if it is set up for locking. */ +#define EVBASE_RELEASE_LOCK(base, lockvar) do { \ + EVLOCK_UNLOCK((base)->lockvar, 0); \ + } while (0) + +/** If lock debugging is enabled, and lock is non-null, assert that 'lock' is + * locked and held by us. */ +#define EVLOCK_ASSERT_LOCKED(lock) \ + do { \ + if ((lock) && evthreadimpl_is_lock_debugging_enabled_()) { \ + EVUTIL_ASSERT(evthread_is_debug_lock_held_(lock)); \ + } \ + } while (0) + +/** Try to grab the lock for 'lockvar' without blocking, and return 1 if we + * manage to get it. */ +static inline int EVLOCK_TRY_LOCK_(void *lock); +static inline int +EVLOCK_TRY_LOCK_(void *lock) +{ + if (lock) { + int r = evthreadimpl_lock_lock_(EVTHREAD_TRY, lock); + return !r; + } else { + /* Locking is disabled either globally or for this thing; + * of course we count as having the lock. */ + return 1; + } +} + +/** Allocate a new condition variable and store it in the void *, condvar */ +#define EVTHREAD_ALLOC_COND(condvar) \ + do { \ + (condvar) = evthreadimpl_cond_alloc_(0); \ + } while (0) +/** Deallocate and free a condition variable in condvar */ +#define EVTHREAD_FREE_COND(cond) \ + do { \ + if (cond) \ + evthreadimpl_cond_free_((cond)); \ + } while (0) +/** Signal one thread waiting on cond */ +#define EVTHREAD_COND_SIGNAL(cond) \ + ( (cond) ? evthreadimpl_cond_signal_((cond), 0) : 0 ) +/** Signal all threads waiting on cond */ +#define EVTHREAD_COND_BROADCAST(cond) \ + ( (cond) ? evthreadimpl_cond_signal_((cond), 1) : 0 ) +/** Wait until the condition 'cond' is signalled. Must be called while + * holding 'lock'. The lock will be released until the condition is + * signalled, at which point it will be acquired again. Returns 0 for + * success, -1 for failure. */ +#define EVTHREAD_COND_WAIT(cond, lock) \ + ( (cond) ? evthreadimpl_cond_wait_((cond), (lock), NULL) : 0 ) +/** As EVTHREAD_COND_WAIT, but gives up after 'tv' has elapsed. Returns 1 + * on timeout. */ +#define EVTHREAD_COND_WAIT_TIMED(cond, lock, tv) \ + ( (cond) ? evthreadimpl_cond_wait_((cond), (lock), (tv)) : 0 ) + +#define EVTHREAD_LOCKING_ENABLED() \ + (evthreadimpl_locking_enabled_()) + +#else /* EVENT__DISABLE_THREAD_SUPPORT */ + +#define EVTHREAD_GET_ID() 1 +#define EVTHREAD_ALLOC_LOCK(lockvar, locktype) EVUTIL_NIL_STMT_ +#define EVTHREAD_FREE_LOCK(lockvar, locktype) EVUTIL_NIL_STMT_ + +#define EVLOCK_LOCK(lockvar, mode) EVUTIL_NIL_STMT_ +#define EVLOCK_UNLOCK(lockvar, mode) EVUTIL_NIL_STMT_ +#define EVLOCK_LOCK2(lock1,lock2,mode1,mode2) EVUTIL_NIL_STMT_ +#define EVLOCK_UNLOCK2(lock1,lock2,mode1,mode2) EVUTIL_NIL_STMT_ + +#define EVBASE_IN_THREAD(base) 1 +#define EVBASE_NEED_NOTIFY(base) 0 +#define EVBASE_ACQUIRE_LOCK(base, lock) EVUTIL_NIL_STMT_ +#define EVBASE_RELEASE_LOCK(base, lock) EVUTIL_NIL_STMT_ +#define EVLOCK_ASSERT_LOCKED(lock) EVUTIL_NIL_STMT_ + +#define EVLOCK_TRY_LOCK_(lock) 1 + +#define EVTHREAD_ALLOC_COND(condvar) EVUTIL_NIL_STMT_ +#define EVTHREAD_FREE_COND(cond) EVUTIL_NIL_STMT_ +#define EVTHREAD_COND_SIGNAL(cond) EVUTIL_NIL_STMT_ +#define EVTHREAD_COND_BROADCAST(cond) EVUTIL_NIL_STMT_ +#define EVTHREAD_COND_WAIT(cond, lock) EVUTIL_NIL_STMT_ +#define EVTHREAD_COND_WAIT_TIMED(cond, lock, howlong) EVUTIL_NIL_STMT_ + +#define EVTHREAD_LOCKING_ENABLED() 0 + +#endif + +/* This code is shared between both lock impls */ +#if ! defined(EVENT__DISABLE_THREAD_SUPPORT) +/** Helper: put lockvar1 and lockvar2 into pointerwise ascending order. */ +#define EVLOCK_SORTLOCKS_(lockvar1, lockvar2) \ + do { \ + if (lockvar1 && lockvar2 && lockvar1 > lockvar2) { \ + void *tmp = lockvar1; \ + lockvar1 = lockvar2; \ + lockvar2 = tmp; \ + } \ + } while (0) + +/** Acquire both lock1 and lock2. Always allocates locks in the same order, + * so that two threads locking two locks with LOCK2 will not deadlock. */ +#define EVLOCK_LOCK2(lock1,lock2,mode1,mode2) \ + do { \ + void *lock1_tmplock_ = (lock1); \ + void *lock2_tmplock_ = (lock2); \ + EVLOCK_SORTLOCKS_(lock1_tmplock_,lock2_tmplock_); \ + EVLOCK_LOCK(lock1_tmplock_,mode1); \ + if (lock2_tmplock_ != lock1_tmplock_) \ + EVLOCK_LOCK(lock2_tmplock_,mode2); \ + } while (0) +/** Release both lock1 and lock2. */ +#define EVLOCK_UNLOCK2(lock1,lock2,mode1,mode2) \ + do { \ + void *lock1_tmplock_ = (lock1); \ + void *lock2_tmplock_ = (lock2); \ + EVLOCK_SORTLOCKS_(lock1_tmplock_,lock2_tmplock_); \ + if (lock2_tmplock_ != lock1_tmplock_) \ + EVLOCK_UNLOCK(lock2_tmplock_,mode2); \ + EVLOCK_UNLOCK(lock1_tmplock_,mode1); \ + } while (0) + +EVENT2_EXPORT_SYMBOL +int evthread_is_debug_lock_held_(void *lock); +void *evthread_debug_get_real_lock_(void *lock); + +void *evthread_setup_global_lock_(void *lock_, unsigned locktype, + int enable_locks); + +#define EVTHREAD_SETUP_GLOBAL_LOCK(lockvar, locktype) \ + do { \ + lockvar = evthread_setup_global_lock_(lockvar, \ + (locktype), enable_locks); \ + if (!lockvar) { \ + event_warn("Couldn't allocate %s", #lockvar); \ + return -1; \ + } \ + } while (0); + +int event_global_setup_locks_(const int enable_locks); +int evsig_global_setup_locks_(const int enable_locks); +int evutil_global_setup_locks_(const int enable_locks); +int evutil_secure_rng_global_setup_locks_(const int enable_locks); + +/** Return current evthread_lock_callbacks */ +EVENT2_EXPORT_SYMBOL +struct evthread_lock_callbacks *evthread_get_lock_callbacks(void); +/** Return current evthread_condition_callbacks */ +struct evthread_condition_callbacks *evthread_get_condition_callbacks(void); +/** Disable locking for internal usage (like global shutdown) */ +void evthreadimpl_disable_lock_debugging_(void); + +#endif + +#ifdef __cplusplus +} +#endif + +#endif /* EVTHREAD_INTERNAL_H_INCLUDED_ */ |