mutex_attr.c

xenomai 很好的linux实时补丁

/*
 * Written by Gilles Chanteperdrix <[e-mail]>.
 *
 * This program is free software; you can redistribute it and/or
 * modify it under the terms of the GNU General Public License as
 * published by the Free Software Foundation; either version 2 of the
 * License, or (at your option) any later version.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program; if not, write to the Free Software
 * Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
 */

/**
 * @addtogroup posix_mutex
 *
 *@{*/

#include <posix/internal.h>

static const pthread_mutexattr_t default_mutex_attr = {
    magic: PSE51_MUTEX_ATTR_MAGIC,
    type: PTHREAD_MUTEX_RECURSIVE,
    protocol: PTHREAD_PRIO_INHERIT
};

/**
 * Initialize a mutex attributes object.
 *
 * This services initializes the mutex attributes object @a attr with default
 * values for all attributes. Default value are :
 * - for the @a type attribute, @a PTHREAD_MUTEX_RECURSIVE;
 * - for the @a protocol attribute, @a PTHREAD_PRIO_INHERIT.
 *
 * Note that the @a pshared attribute is not supported: mutexes created by
 * Xenomai POSIX skin may be shared by kernel-space modules and user-space
 * processes through shared memory.
 *
 * If this service is called specifying a mutex attributes object that was
 * already initialized, the attributes object is reinitialized.
 *
 * @param attr the mutex attributes object to be initialized.
 *
 * @return 0 on success;
 * @return an error number if:
 * - ENOMEM, the mutex attributes object pointer @a attr is @a NULL.
 *
 * @par Valid contexts:
 * - kernel module initialization or cleanup routine;
 * - Xenomai kernel-space real-time thread.
 *
 * @see http://www.opengroup.org/onlinepubs/000095399/functions/pthread_mutexattr_init.html
 * 
 */
int pthread_mutexattr_init (pthread_mutexattr_t *attr)

{
    if (!attr)
        return ENOMEM;

    *attr = default_mutex_attr;

    return 0;    
}

/**
 * Destroy a mutex attributes object.
 *
 * This service destroys the mutex attributes object @a attr. The object becomes
 * invalid for all mutex services (they all return EINVAL) except
 * pthread_mutexattr_init().
 *
 * @param attr the initialized mutex attributes object to be destroyed.
 *
 * @return 0 on success;
 * @return an error number if:
 * - EINVAL, the mutex attributes object @a attr is invalid.
 *
 * @par Valid contexts:
 * - kernel module initialization or cleanup routine;
 * - Xenomai kernel-space real-time thread.
 *
 * @see http://www.opengroup.org/onlinepubs/000095399/functions/pthread_mutexattr_destroy.html
 * 
 */
int pthread_mutexattr_destroy (pthread_mutexattr_t *attr)

{
    spl_t s;

    xnlock_get_irqsave(&nklock, s);

    if (!pse51_obj_active(attr, PSE51_MUTEX_ATTR_MAGIC, pthread_attr_t))
	{
        xnlock_put_irqrestore(&nklock, s);
        return EINVAL;
	}
    
    pse51_mark_deleted(attr);
    xnlock_put_irqrestore(&nklock, s);

    return 0;
}

/**
 * Get the mutex type attribute from a mutex attributes object.
 *
 * This service stores, at the address @a type, the value of the @a type
 * attribute in the mutex attributes object @a attr.
 *
 * See pthread_mutex_lock() and pthread_mutex_unlock() documentations for a
 * description of the values of the @a type attribute and their effect on a
 * mutex.
 *
 * @param attr an initialized mutex attributes object,
 *
 * @param type address where the @a type attribute value will be stored on
 * success.
 *
 * @return 0 on sucess,
 * @return an error number if:
 * - EINVAL, the @a type address is invalid;
 * - EINVAL, the mutex attributes object @a attr is invalid.
 *
 * @par Valid contexts:
 * - kernel module initialization or cleanup routine;
 * - Xenomai kernel-space real-time thread.
 *
 * @see http://www.opengroup.org/onlinepubs/000095399/functions/pthread_mutexattr_gettype.html
 * 
 */
int pthread_mutexattr_gettype (const pthread_mutexattr_t *attr, int *type)

{
    spl_t s;

    if (!type || !attr)
        return EINVAL;

    xnlock_get_irqsave(&nklock, s);

    if (!pse51_obj_active(attr, PSE51_MUTEX_ATTR_MAGIC, pthread_attr_t))
	{
        xnlock_put_irqrestore(&nklock, s);
        return EINVAL;
	}

    *type = attr->type;

    xnlock_put_irqrestore(&nklock, s);

    return 0;    
}

/**
 * Set the mutex type attribute of a mutex attributes object.
 *
 * This service set the @a type attribute of the mutex attributes object
 * @a attr.
 *
 * See pthread_mutex_lock() and pthread_mutex_unlock() documentations for a
 * description of the values of the @a type attribute and their effect on a
 * mutex.
 *
 * The @a PTHREAD_MUTEX_DEFAULT default @a type is the same as @a
 * PTHREAD_MUTEX_RECURSIVE. Note that using a Xenomai POSIX skin recursive mutex
 * with a Xenomai POSIX skin condition variable is safe (see pthread_cond_wait()
 * documentation).
 *
 * @param attr an initialized mutex attributes object,
 *
 * @param type value of the @a type attribute. 
 *
 * @return 0 on success,
 * @return an error number if:
 * - EINVAL, the mutex attributes object @a attr is invalid;
 * - EINVAL, the value of @a type is invalid for the @a type attribute.
 *
 * @par Valid contexts:
 * - kernel module initialization or cleanup routine;
 * - Xenomai kernel-space real-time thread.
 *
 * @see http://www.opengroup.org/onlinepubs/000095399/functions/pthread_mutexattr_settype.html
 * 
 */
int pthread_mutexattr_settype (pthread_mutexattr_t *attr, int type)

{
    spl_t s;

    if (!attr)
        return EINVAL;

    xnlock_get_irqsave(&nklock, s);

    if (!pse51_obj_active(attr, PSE51_MUTEX_ATTR_MAGIC, pthread_attr_t))
	{
        xnlock_put_irqrestore(&nklock, s);
        return EINVAL;
	}

    switch (type)
	{
	default:

	    xnlock_put_irqrestore(&nklock, s);
	    return EINVAL;

	case PTHREAD_MUTEX_DEFAULT:
	    type = PTHREAD_MUTEX_RECURSIVE;

	case PTHREAD_MUTEX_NORMAL:
	case PTHREAD_MUTEX_RECURSIVE:
	case PTHREAD_MUTEX_ERRORCHECK:
	    break;
    }
    
    attr->type = type;

    xnlock_put_irqrestore(&nklock, s);

    return 0;
}

/**
 * Get the protocol attribute from a mutex attributes object.
 *
 * This service stores, at the address @a proto, the value of the @a protocol
 * attribute in the mutex attributes object @a attr.
 *
 * The @a protcol attribute may only be one of @a PTHREAD_PRIO_NONE and @a
 * PTHREAD_PRIO_INHERIT.
 *
 * @param attr an initialized mutex attributes object;
 *
 * @param proto address where the value of the @a protocol attribute will be
 * stored on success.
 *
 * @return 0 on success,
 * @return an error number if:
 * - EINVAL, the @a proto address is invalid;
 * - EINVAL, the mutex attributes object @a attr is invalid.
 *
 * @par Valid contexts:
 * - kernel module initialization or cleanup routine;
 * - Xenomai kernel-space real-time thread.
 *
 * @see http://www.opengroup.org/onlinepubs/000095399/functions/pthread_mutexattr_getprotocol.html
 * 
 */
int pthread_mutexattr_getprotocol (const pthread_mutexattr_t *attr, int *proto)

{
    spl_t s;

    if (!proto || !attr)
        return EINVAL;
    
    xnlock_get_irqsave(&nklock, s);

    if (!pse51_obj_active(attr, PSE51_MUTEX_ATTR_MAGIC, pthread_attr_t))
	{
        xnlock_put_irqrestore(&nklock, s);
        return EINVAL;
	}

    *proto = attr->protocol;

    xnlock_put_irqrestore(&nklock, s);

    return 0;
}

/**
 * Set the protocol attribute of a mutex attributes object.
 *
 * This service set the @a type attribute of the mutex attributes object
 * @a attr.
 *
 * @param attr an initialized mutex attributes object,
 *
 * @param proto value of the @a protocol attribute, may be one of:
 * - PTHREAD_PRIO_NONE, meaning that a mutex created with the attributes object
 *   @a attr will not follow any priority protocol;
 * - PTHREAD_PRIO_INHERIT, meaning that a mutex created with the attributes
 *   object @a attr, will follow the priority inheritance protocol.
 *
 * The value PTHREAD_PRIO_PROTECT (priority ceiling protocol) is unsupported.
 *
 * @return 0 on success,
 * @return an error status if:
 * - EINVAL, the mutex attributes object @a attr is invalid;
 * - ENOTSUP, the value of @a proto is unsupported;
 * - EINVAL, the value of @a proto is invalid.
 *
 * @par Valid contexts:
 * - kernel module initialization or cleanup routine;
 * - Xenomai kernel-space real-time thread.
 *
 * @see http://www.opengroup.org/onlinepubs/000095399/functions/pthread_mutexattr_setprotocol.html
 * 
 */
int pthread_mutexattr_setprotocol (pthread_mutexattr_t *attr, int proto)

{
    spl_t s;

    if (!attr)
        return EINVAL;

    xnlock_get_irqsave(&nklock, s);

    if (!pse51_obj_active(attr, PSE51_MUTEX_ATTR_MAGIC, pthread_attr_t))
	{
        xnlock_put_irqrestore(&nklock, s);
        return EINVAL;
	}

    switch (proto)
	{
	default:

	    xnlock_put_irqrestore(&nklock, s);
	    return EINVAL;

	case PTHREAD_PRIO_PROTECT:

	    xnlock_put_irqrestore(&nklock, s);
	    return ENOTSUP;

	case PTHREAD_PRIO_NONE:
	case PTHREAD_PRIO_INHERIT:
	    break;
	}
    
    attr->protocol = proto;

    xnlock_put_irqrestore(&nklock, s);

    return 0;
}

/*@}*/

EXPORT_SYMBOL(pthread_mutexattr_init);
EXPORT_SYMBOL(pthread_mutexattr_destroy);
EXPORT_SYMBOL(pthread_mutexattr_gettype);
EXPORT_SYMBOL(pthread_mutexattr_settype);
EXPORT_SYMBOL(pthread_mutexattr_getprotocol);
EXPORT_SYMBOL(pthread_mutexattr_setprotocol);