thread.cc

cygwin, 著名的在win32下模拟unix操作系统的东东

    api_fatal ("doesn't understand PROCESS_SHARED semaphores variables");
  /* FIXME: duplicate code here and in the constructor. */
  this->win32_obj_id = ::CreateSemaphore (&sec_none_nih, currentvalue, LONG_MAX, NULL);
  if (!win32_obj_id)
    api_fatal ("failed to create new win32 semaphore");
}

verifyable_object::verifyable_object (long verifyer):
magic (verifyer)
{
}

verifyable_object::~verifyable_object ()
{
  magic = 0;
}

/* Generic memory acccess routine - where should it live ? */
int __stdcall
check_valid_pointer (void const *pointer)
{
  if (!pointer || IsBadWritePtr ((void *) pointer, sizeof (verifyable_object)))
    return EFAULT;
  return 0;
}

verifyable_object_state
verifyable_object_isvalid (void const * objectptr, long magic, void *static_ptr)
{
  verifyable_object **object = (verifyable_object **)objectptr;
  if (check_valid_pointer (object))
    return INVALID_OBJECT;
  if (static_ptr && *object == static_ptr)
    return VALID_STATIC_OBJECT;
  if (!*object)
    return INVALID_OBJECT;
  if (check_valid_pointer (*object))
    return INVALID_OBJECT;
  if ((*object)->magic != magic)
    return INVALID_OBJECT;
  return VALID_OBJECT;
}

verifyable_object_state
verifyable_object_isvalid (void const * objectptr, long magic)
{
  return verifyable_object_isvalid (objectptr, magic, NULL);
}

/* Pthreads */
void *
pthread::thread_init_wrapper (void *_arg)
{
  // Setup the local/global storage of this thread

  pthread *thread = (pthread *) _arg;
  struct __reent_t local_reent;
  struct _winsup_t local_winsup;
  struct _reent local_clib = _REENT_INIT (local_clib);

  struct sigaction _sigs[NSIG];
  sigset_t _sig_mask;		/* one set for everything to ignore. */
  LONG _sigtodo[NSIG + __SIGOFFSET];

  // setup signal structures
  thread->sigs = _sigs;
  thread->sigmask = &_sig_mask;
  thread->sigtodo = _sigtodo;

  memset (&local_winsup, 0, sizeof (struct _winsup_t));

  local_reent._clib = &local_clib;
  local_reent._winsup = &local_winsup;

  local_winsup._process_logmask = LOG_UPTO (LOG_DEBUG);

  MT_INTERFACE->reent_key.set (&local_reent);

  thread->setThreadIdtoCurrent ();
  setTlsSelfPointer (thread);

  thread->mutex.Lock ();
  // if thread is detached force cleanup on exit
  if (thread->attr.joinable == PTHREAD_CREATE_DETACHED && thread->joiner == NULL)
    thread->joiner = thread;
  thread->mutex.UnLock ();

#ifdef _CYG_THREAD_FAILSAFE
  if (_REENT == _impure_ptr)
    system_printf ("local storage for thread isn't setup correctly");
#endif

  thread_printf ("started thread %p %p %p %p %p %p", _arg, &local_clib,
		 _impure_ptr, thread, thread->function, thread->arg);

  // call the user's thread
  void *ret = thread->function (thread->arg);

  thread->exit (ret);

#if 0
// ??? This code only runs if the thread exits by returning.
// it's all now in __pthread_exit ();
#endif
  /* never reached */
  return 0;
}

bool
pthread::isGoodObject (pthread_t const *thread)
{
  if (verifyable_object_isvalid (thread, PTHREAD_MAGIC) != VALID_OBJECT)
    return false;
  return true;
}

unsigned long
pthread::getsequence_np ()
{
  return getThreadId ();
}

int
pthread::create (pthread_t *thread, const pthread_attr_t *attr,
		  void *(*start_routine) (void *), void *arg)
{
  DECLARE_TLS_STORAGE;
  if (attr && !pthread_attr::isGoodObject (attr))
    return EINVAL;

  *thread = new pthread ();
  (*thread)->create (start_routine, attr ? *attr : NULL, arg);
  if (!isGoodObject (thread))
    {
      delete (*thread);
      *thread = NULL;
      return EAGAIN;
    }

  return 0;
}

int
pthread::once (pthread_once_t *once_control, void (*init_routine) (void))
{
  // already done ?
  if (once_control->state)
    return 0;

  pthread_mutex_lock (&once_control->mutex);
  /* Here we must set a cancellation handler to unlock the mutex if needed */
  /* but a cancellation handler is not the right thing. We need this in the thread
   *cleanup routine. Assumption: a thread can only be in one pthread_once routine
   *at a time. Stote a mutex_t *in the pthread_structure. if that's non null unlock
   *on pthread_exit ();
   */
  if (!once_control->state)
    {
      init_routine ();
      once_control->state = 1;
    }
  /* Here we must remove our cancellation handler */
  pthread_mutex_unlock (&once_control->mutex);
  return 0;
}

int
pthread::cancel (pthread_t thread)
{
  if (!isGoodObject (&thread))
    return ESRCH;

  return thread->cancel ();
}

/* Races in pthread_atfork:
   We are race safe in that any additions to the lists are made via
   InterlockedExchangePointer.
   However, if the user application doesn't perform syncronisation of some sort
   It's not guaranteed that a near simultaneous call to pthread_atfork and fork
   will result in the new atfork handlers being calls.
   More rigorous internal syncronisation isn't needed as the user program isn't
   guaranteeing their own state.

   as far as multiple calls to pthread_atfork, the worst case is simultaneous calls
   will result in an indeterminate order for parent and child calls (what gets inserted
   first isn't guaranteed.)

   There is one potential race... Does the result of InterlockedExchangePointer
   get committed to the return location _before_ any context switches can occur?
   If yes, we're safe, if no, we're not.  */
void
pthread::atforkprepare (void)
{
  MT_INTERFACE->fixup_before_fork ();

  callback *cb = MT_INTERFACE->pthread_prepare;
  while (cb)
    {
      cb->cb ();
      cb = cb->next;
    }
}

void
pthread::atforkparent (void)
{
  callback *cb = MT_INTERFACE->pthread_parent;
  while (cb)
    {
      cb->cb ();
      cb = cb->next;
    }
}

void
pthread::atforkchild (void)
{
  MT_INTERFACE->fixup_after_fork ();

  callback *cb = MT_INTERFACE->pthread_child;
  while (cb)
    {
      cb->cb ();
      cb = cb->next;
    }
}

/* Register a set of functions to run before and after fork.
   prepare calls are called in LI-FC order.
   parent and child calls are called in FI-FC order.  */
int
pthread::atfork (void (*prepare)(void), void (*parent)(void), void (*child)(void))
{
  callback *prepcb = NULL, *parentcb = NULL, *childcb = NULL;
  if (prepare)
    {
      prepcb = new callback;
      if (!prepcb)
	return ENOMEM;
    }
  if (parent)
    {
      parentcb = new callback;
      if (!parentcb)
	{
	  if (prepcb)
	    delete prepcb;
	  return ENOMEM;
	}
    }
  if (child)
    {
      childcb = new callback;
      if (!childcb)
	{
	  if (prepcb)
	    delete prepcb;
	  if (parentcb)
	    delete parentcb;
	  return ENOMEM;
	}
    }

  if (prepcb)
  {
    prepcb->cb = prepare;
    prepcb->next = (callback *) InterlockedExchangePointer ((LONG *) &MT_INTERFACE->pthread_prepare, (long int) prepcb);
  }
  if (parentcb)
  {
    parentcb->cb = parent;
    callback **t = &MT_INTERFACE->pthread_parent;
    while (*t)
      t = &(*t)->next;
    /* t = pointer to last next in the list */
    parentcb->next = (callback *) InterlockedExchangePointer ((LONG *) t, (long int) parentcb);
  }
  if (childcb)
  {
    childcb->cb = child;
    callback **t = &MT_INTERFACE->pthread_child;
    while (*t)
      t = &(*t)->next;
    /* t = pointer to last next in the list */
    childcb->next = (callback *) InterlockedExchangePointer ((LONG *) t, (long int) childcb);
  }
  return 0;
}

int
__pthread_attr_init (pthread_attr_t *attr)
{
  if (check_valid_pointer (attr))
    return EINVAL;
  *attr = new pthread_attr;
  if (!pthread_attr::isGoodObject (attr))
    {
      delete (*attr);
      *attr = NULL;
      return EAGAIN;
    }
  return 0;
}

int
__pthread_attr_getinheritsched (const pthread_attr_t *attr,
				int *inheritsched)
{
  if (!pthread_attr::isGoodObject (attr))
    return EINVAL;
  *inheritsched = (*attr)->inheritsched;
  return 0;
}

int
__pthread_attr_getschedparam (const pthread_attr_t *attr,
			      struct sched_param *param)
{
  if (!pthread_attr::isGoodObject (attr))
    return EINVAL;
  *param = (*attr)->schedparam;
  return 0;
}

/* From a pure code point of view, this should call a helper in sched.cc,
   to allow for someone adding scheduler policy changes to win32 in the future.
   However that's extremely unlikely, so short and sweet will do us */
int
__pthread_attr_getschedpolicy (const pthread_attr_t *attr, int *policy)
{
  if (!pthread_attr::isGoodObject (attr))
    return EINVAL;
  *policy = SCHED_FIFO;
  return 0;
}


int
__pthread_attr_getscope (const pthread_attr_t *attr, int *contentionscope)
{
  if (!pthread_attr::isGoodObject (attr))
    return EINVAL;
  *contentionscope = (*attr)->contentionscope;
  return 0;
}

int
__pthread_attr_setdetachstate (pthread_attr_t *attr, int detachstate)
{
  if (!pthread_attr::isGoodObject (attr))
    return EINVAL;
  if (detachstate < 0 || detachstate > 1)
    return EINVAL;
  (*attr)->joinable = detachstate;
  return 0;
}

int
__pthread_attr_getdetachstate (const pthread_attr_t *attr, int *detachstate)
{
  if (!pthread_attr::isGoodObject (attr))
    return EINVAL;
  *detachstate = (*attr)->joinable;
  return 0;
}

int
__pthread_attr_setinheritsched (pthread_attr_t *attr, int inheritsched)
{
  if (!pthread_attr::isGoodObject (attr))
    return EINVAL;
  if (inheritsched != PTHREAD_INHERIT_SCHED
      && inheritsched != PTHREAD_EXPLICIT_SCHED)
    return ENOTSUP;
  (*attr)->inheritsched = inheritsched;
  return 0;
}

int
__pthread_attr_setschedparam (pthread_attr_t *attr,
			      const struct sched_param *param)
{
  if (!pthread_attr::isGoodObject (attr))
    return EINVAL;
  if (!valid_sched_parameters (param))
    return ENOTSUP;
  (*attr)->schedparam = *param;
  return 0;
}

/* See __pthread_attr_getschedpolicy for some notes */
int
__pthread_attr_setschedpolicy (pthread_attr_t *attr, int policy)
{
  if (!pthread_attr::isGoodObject (attr))
    return EINVAL;
  if (policy != SCHED_FIFO)
    return ENOTSUP;
  return 0;
}

int
__pthread_attr_setscope (pthread_attr_t *attr, int contentionscope)
{
  if (!pthread_attr::isGoodObject (attr))
    return EINVAL;
  if (contentionscope != PTHREAD_SCOPE_SYSTEM
      && contentionscope != PTHREAD_SCOPE_PROCESS)
    return EINVAL;
  /* In future, we may be able to support system scope by escalating the thread
     priority to exceed the priority class. For now we only support PROCESS scope. */
  if (contentionscope != PTHREAD_SCOPE_PROCESS)
    return ENOTSUP;
  (*attr)->contentionscope = contentionscope;
  return 0;
}

int
__pthread_attr_setstacksize (pthread_attr_t *attr, size_t size)
{
  if (!pthread_attr::isGoodObject (attr))
    return EINVAL;
  (*attr)->stacksize = size;
  return 0;
}

int
__pthread_attr_getstacksize (const pthread_attr_t *attr, size_t *size)
{
  if (!pthread_attr::isGoodObject (attr))
    return EINVAL;
  *size = (*attr)->stacksize;
  return 0;
}

int
__pthread_attr_destroy (pthread_attr_t *attr)
{
  if (!pthread_attr::isGoodObject (attr))
    return EINVAL;
  delete (*attr);
  *attr = NULL;
  return 0;
}

int
pthread::join (pthread_t *thread, void **return_val)
{
   pthread_t joiner = self ();

   if (!isGoodObject (&joiner))
     return EINVAL;

   // Initialize return val with NULL
   if (return_val)
     *return_val = NULL;

  /* FIXME: wait on the thread cancellation event as well - we are a cancellation point*/
  if (!isGoodObject (thread))
    return ESRCH;

  if (__pthread_equal (thread,&joiner))
    return EDEADLK;

  (*thread)->mutex.Lock ();

  if ((*thread)->attr.joinable == PTHREAD_CREATE_DETACHED)
    {
      (*thread)->mutex.UnLock ();
      return EINVAL;
    }
  else
    {
      (*thread)->joiner = joiner;
      (*thread)->attr.joinable = PTHREAD_CREATE_DETACHED;
      (*thread)->mutex.UnLock ();
      WaitForSingleObject ((*thread)->win32_obj_id, INFINITE);
      if (return_val)
	 *return_val = (*thread)->return_ptr;
      // cleanup
      delete (*thread);
    }	/* End if */

  pthread_testcancel ();

  return 0;
}

int
pthread::detach (pthread_t *thread)
{
  if (!isGoodObject (thread))
    return ESRCH;

  (*thread)->mutex.Lock ();
  if ((*thread)->attr.joinable == PTHREAD_CREATE_DETACHED)
    {
      (*thread)->mutex.UnLock ();
      return EINVAL;
    }

  // check if thread is still alive
  if (WAIT_TIMEOUT == WaitForSingleObject ((*thread)->win32_obj_id, 0))
    {
      // force cleanup on exit
      (*thread)->joiner = *thread;
      (*thread)->attr.joinable = PTHREAD_CREATE_DETACHED;
      (*thread)->mutex.UnLock ();
    }
  else
    {
      // thread has already terminated.
      (*thread)->mutex.UnLock ();
      delete (*thread);
    }

  return 0;
}

int
pthread::suspend (pthread_t *thread)
{
  if (!isGoodObject (thread))
    return ESRCH;

  if ((*thread)->suspended == false)
    {
      (*thread)->suspended = true;
      SuspendThread ((*thread)->win32_obj_id);
    }

  return 0;
}


int
pthread::resume (pthread_t *thread)
{
  if (!isGoodObject (thread))
    return ESRCH;

  if ((*thread)->suspended == true)
    ResumeThread ((*thread)->win32_obj_id);
  (*thread)->suspended = false;

  return 0;
}

/* provided for source level compatability.
   See http://www.opengroup.org/onlinepubs/007908799/xsh/pthread_getconcurrency.html
*/
int
__pthread_getconcurrency (void)
{
  return MT_INTERFACE->concurrency;
}

/* keep this in sync with sched.cc */
int
__pthread_getschedparam (pthread_t thread, int *policy,
			 struct sched_param *param)
{
  if (!pthread::isGoodObject (&thread))
    return ESRCH;
  *policy = SCHED_FIFO;
  /* we don't return the current effective priority, we return the current
     requested priority */
  *param = thread->attr.schedparam;
  return 0;
}

/* Thread SpecificData */
int
__pthread_key_create (pthread_key_t *key, void (*destructor) (void *))
{
  /* The opengroup docs don't define if we should check this or not,
     but creation is relatively rare.  */
  if (pthread_key::isGoodObject (key))
    return EBUSY;

  *key = new pthread_key (destructor);

  if (!pthread_key::isGoodObject (key))
    {
      delete (*key);
      *key = NULL;
      return EAGAIN;
    }
  return 0;
}

int
__pthread_key_delete (pthread_key_t key)
{
  if (!pthread_key::isGoodObject (&key))
    return EINVAL;

  delete (key);
  return 0;
}

/* provided for source level compatability.  See
http://www.opengroup.org/onlinepubs/007908799/xsh/pthread_getconcurrency.html
*/
int
__pthread_setconcurrency (int new_level)
{
  if (new_level < 0)
    return EINVAL;
  MT_INTERFACE->concurrency = new_level;
  return 0;
}

/* keep syncronised with sched.cc */
int
__pthread_setschedparam (pthread_t thread, int policy,
			 const struct sched_param *param)
{
  if (!pthread::isGoodObject (&thread))
    return ESRCH;
  if (policy != SCHED_FIFO)
    return ENOTSUP;
  if (!param)
    return EINVAL;
  int rv =
    sched_set_thread_priority (thread->win32_obj_id, param->sched_priority);
  if (!rv)
    thread->attr.schedparam.sched_priority = param->sched_priority;
  return rv;
}


int
__pthread_setspecific (pthread_key_t key, const void *value)
{
  if (!pthread_key::isGoodObject (&key))
    return EINVAL;
  (key)->set (value);
  return 0;
}

void *
__pthread_getspecific (pthread_key_t key)
{
  if (!pthread_key::isGoodObject (&key))
    return NULL;

  return (key)->get ();

}

/* Thread synchronisation */
bool
pthread_cond::isGoodObject (pthread_cond_t const *cond)
{
  if (verifyable_object_isvalid (cond, PTHREAD_COND_MAGIC) != VALID_OBJECT)
    return false;
  return true;
}

bool
pthread_cond::isGoodInitializer (pthread_cond_t const *cond)