kc3-lang/libevent/evthread-internal.h

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• Hash : 648af99a
  Author :
  Date : 2022-07-09T17:20:26
  

  Fix EVBASE_ACQUIRE_LOCK/EVBASE_RELEASE_LOCK for EVENT__DISABLE_THREAD_SUPPORT
  

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• evthread-internal.h

• /*
   * 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) (void)(base)
  #define EVBASE_RELEASE_LOCK(base, lock) (void)(base)
  #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_ */
  

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