semevent-posix.cpp revision 660fd430a3a8cfa16505d04c7c577acf89d45a40
/* $Id$ */
/** @file
* IPRT - Event Semaphore, POSIX.
*/
/*
* Copyright (C) 2006-2007 Sun Microsystems, Inc.
*
* This file is part of VirtualBox Open Source Edition (OSE), as
* available from http://www.virtualbox.org. This file is free software;
* General Public License (GPL) as published by the Free Software
* Foundation, in version 2 as it comes in the "COPYING" file of the
* VirtualBox OSE distribution. VirtualBox OSE is distributed in the
* hope that it will be useful, but WITHOUT ANY WARRANTY of any kind.
*
* The contents of this file may alternatively be used under the terms
* of the Common Development and Distribution License Version 1.0
* (CDDL) only, as it comes in the "COPYING.CDDL" file of the
* VirtualBox OSE distribution, in which case the provisions of the
* CDDL are applicable instead of those of the GPL.
*
* You may elect to license modified versions of this file under the
* terms and conditions of either the GPL or the CDDL or both.
*
* Please contact Sun Microsystems, Inc., 4150 Network Circle, Santa
* Clara, CA 95054 USA or visit http://www.sun.com if you need
* additional information or have any questions.
*/
/*******************************************************************************
* Header Files *
*******************************************************************************/
#include <iprt/semaphore.h>
#include <errno.h>
#include <pthread.h>
#include <unistd.h>
#ifdef RT_OS_DARWIN
# define pthread_yield() pthread_yield_np()
#endif
#ifdef RT_OS_SOLARIS
# include <sched.h>
# define pthread_yield() sched_yield()
#endif
/*******************************************************************************
* Structures and Typedefs *
*******************************************************************************/
/** Internal representation of the POSIX implementation of an Event semaphore.
* The POSIX implementation uses a mutex and a condition variable to implement
* the automatic reset event semaphore semantics.
*/
struct RTSEMEVENTINTERNAL
{
/** pthread condition. */
/** pthread mutex which protects the condition and the event state. */
/** The state of the semaphore.
* This is operated while owning mutex and using atomic updating. */
/** Number of waiters. */
};
/** The valus of the u32State variable in a RTSEMEVENTINTERNAL.
* @{ */
/** The object isn't initialized. */
#define EVENT_STATE_UNINITIALIZED 0
/** The semaphore is is signaled. */
#define EVENT_STATE_SIGNALED 0xff00ff00
/** The semaphore is not signaled. */
#define EVENT_STATE_NOT_SIGNALED 0x00ff00ff
/** @} */
/**
* Validate an Event semaphore handle passed to one of the interface.
*
* @returns true if valid.
* @returns false if invalid.
* @param pIntEventSem Pointer to the event semaphore to validate.
*/
{
return false;
uint32_t u32 = pIntEventSem->u32State; /* this is volatile, so a explicit read like this is needed. */
if ( u32 != EVENT_STATE_NOT_SIGNALED
&& u32 != EVENT_STATE_SIGNALED)
return false;
return true;
}
{
int rc;
/*
* Allocate semaphore handle.
*/
struct RTSEMEVENTINTERNAL *pIntEventSem = (struct RTSEMEVENTINTERNAL *)RTMemAlloc(sizeof(struct RTSEMEVENTINTERNAL));
if (pIntEventSem)
{
/*
* Create the condition variable.
*/
if (!rc)
{
if (!rc)
{
/*
* Create the semaphore.
*/
if (!rc)
{
if (!rc)
{
return VINF_SUCCESS;
}
}
}
}
}
else
rc = VERR_NO_MEMORY;
return rc;
}
{
/*
* Validate handle.
*/
return VERR_INVALID_HANDLE;
if (!rtsemEventValid(EventSem))
{
return VERR_INVALID_HANDLE;
}
/*
* Abort all waiters forcing them to return failure.
*
*/
int rc;
for (int i = 30; i > 0; i--)
{
break;
usleep(1000);
if (rc)
{
return RTErrConvertFromErrno(rc);
}
/*
* Destroy the semaphore
* If it's busy we'll wait a bit to give the threads a chance to be scheduled.
*/
for (int i = 30; i > 0; i--)
{
break;
usleep(1000);
}
if (rc)
{
return RTErrConvertFromErrno(rc);
}
/*
* Free the semaphore memory and be gone.
*/
return VINF_SUCCESS;
}
{
/*
* Validate input.
*/
if (!rtsemEventValid(EventSem))
{
return VERR_INVALID_HANDLE;
}
/*
* Lock the mutex semaphore.
*/
if (rc)
{
return RTErrConvertFromErrno(rc);
}
/*
* Check the state.
*/
{
}
{
}
else
/*
* Release the mutex and return.
*/
if (rc)
return RTErrConvertFromErrno(rc);
if (rc2)
return RTErrConvertFromErrno(rc2);
return VINF_SUCCESS;
}
{
/*
* Validate input.
*/
if (!rtsemEventValid(EventSem))
{
return VERR_INVALID_HANDLE;
}
/*
* Timed or indefinite wait?
*/
if (cMillies == RT_INDEFINITE_WAIT)
{
/* for fairness, yield before going to sleep. */
/* take mutex */
if (rc)
{
return RTErrConvertFromErrno(rc);
}
for (;;)
{
/* check state. */
{
return VINF_SUCCESS;
}
{
return VERR_SEM_DESTROYED;
}
/* wait */
if (rc)
{
return RTErrConvertFromErrno(rc);
}
}
}
else
{
/*
* Get current time and calc end of wait time.
*/
#ifdef RT_OS_DARWIN
#else
#endif
if (cMillies != 0)
{
{
}
}
/* for fairness, yield before going to sleep. */
/* take mutex */
#ifdef RT_OS_DARWIN
#else
#endif
if (rc)
{
return RTErrConvertFromErrno(rc);
}
for (;;)
{
/* check state. */
{
return VINF_SUCCESS;
}
{
return VERR_SEM_DESTROYED;
}
/* wait */
if (rc && (rc != EINTR || !fAutoResume)) /* according to SuS this function shall not return EINTR, but linux man page says differently. */
{
return RTErrConvertFromErrno(rc);
}
} /* for (;;) */
}
}
{
return rc;
}
{
}