WebSVN - shark - Blame - Rev 228 - /shark/trunk/kernel/mutex.c

Rev	Author	Line No.	Line
2	pj	1	/*
		2	* Project: S.Ha.R.K.
		3	*
		4	* Coordinators:
		5	* Giorgio Buttazzo <giorgio@sssup.it>
		6	* Paolo Gai <pj@gandalf.sssup.it>
		7	*
		8	* Authors :
		9	* Paolo Gai <pj@gandalf.sssup.it>
		10	* (see the web pages for full authors list)
		11	*
		12	* ReTiS Lab (Scuola Superiore S.Anna - Pisa - Italy)
		13	*
		14	* http://www.sssup.it
		15	* http://retis.sssup.it
		16	* http://shark.sssup.it
		17	*/
		18
		19	/**
		20	------------
228	giacomo	21	CVS : $Id: mutex.c,v 1.3 2003-09-12 10:10:41 giacomo Exp $
2	pj	22
		23	File: $File$
228	giacomo	24	Revision: $Revision: 1.3 $
		25	Last update: $Date: 2003-09-12 10:10:41 $
2	pj	26	------------
		27
		28	This file contains the mutex and condition variables handling functions.
		29
		30
		31	The mutex init function try to find a resource level with
		32	rtype = MUTEX_RTYPE that can accept a mutex of the type of that
		33	contained in mutexattr_t.
		34
		35	when found, it simply calls the level mutex init function.
		36
		37	Note that a mutex attribute must be specificated, whereas the
		38	pthread_mutex_init accepts a pthread_mutexattr equal to NULL!!!
		39
		40
		41	returns an integer of value:
		42
		43	EAGAIN The system lacked the necessarty resources to initialize another mutex
		44	ENOMEM Insufficient memory exist to initialize the mutex
		45	EPERM The caller does not have the privilege to perform the operation
		46	EBUSY An init on a non-destroyed mutex is called
		47	EINVAL the value specified by attr parameter is invalid
		48	(no resource module found to handle the rtype...)
		49
		50
		51	The others functions simply call the module-dependent functions...
		52
		53	**/
		54
		55	/*
		56	* Copyright (C) 2000 Paolo Gai
		57	*
		58	* This program is free software; you can redistribute it and/or modify
		59	* it under the terms of the GNU General Public License as published by
		60	* the Free Software Foundation; either version 2 of the License, or
		61	* (at your option) any later version.
		62	*
		63	* This program is distributed in the hope that it will be useful,
		64	* but WITHOUT ANY WARRANTY; without even the implied warranty of
		65	* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
		66	* GNU General Public License for more details.
		67	*
		68	* You should have received a copy of the GNU General Public License
		69	* along with this program; if not, write to the Free Software
		70	* Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
		71	*
		72	*/
		73
		74
		75
		76	#include <kernel/const.h>
		77	#include <sys/types.h>
		78	#include <kernel/model.h>
		79	#include <kernel/descr.h>
		80	#include <kernel/var.h>
		81	#include <kernel/func.h>
		82	#include <errno.h>
		83
		84	/---------------------------------------------------------------------/
		85	/* Mutexes */
		86	/---------------------------------------------------------------------/
		87
		88
		89	int mutex_init(mutex_t mutex, const mutexattr_t attr)
		90	{
		91	RLEVEL l;
38	pj	92	int result;
2	pj	93
		94	kern_cli();
		95	mutex->mutexlevel = -1;
		96	mutex->use = 0;
		97
		98	for (l=0; l<res_levels; l++) {
		99	if (resource_table[l]->rtype == MUTEX_RTYPE) {
		100	/* the cast to mutex_resource_des is legal */
		101	mutex_resource_des m = (mutex_resource_des )resource_table[l];
		102
		103	/* can the mutex level manage the mutexattr_t ? */
228	giacomo	104	if ((result = m->init(l, mutex, attr)) >=0) {
		105	kern_sti();
38	pj	106	return result;
228	giacomo	107	}
2	pj	108	}
		109	}
		110	kern_sti();
		111
38	pj	112	return EINVAL;
2	pj	113	}
		114
		115
		116	int mutex_destroy(mutex_t *mutex)
		117	{
		118	mutex_resource_des *m;
		119
		120	if (mutex->mutexlevel == -1)
		121	return (EINVAL);
		122
		123	if (mutex->use)
		124	return (EBUSY);
		125
		126	m = (mutex_resource_des *)resource_table[mutex->mutexlevel];
		127
		128	return m->destroy(mutex->mutexlevel, mutex);
		129	}
		130
		131	int mutex_lock(mutex_t *mutex)
		132	{
		133	mutex_resource_des *m;
		134
		135	if (mutex->mutexlevel == -1)
		136	return (EINVAL);
		137
		138	m = (mutex_resource_des *)resource_table[mutex->mutexlevel];
		139
		140	return m->lock(mutex->mutexlevel, mutex);
		141	}
		142
		143	int mutex_trylock(mutex_t *mutex)
		144	{
		145	mutex_resource_des *m;
		146
		147	if (mutex->mutexlevel == -1)
		148	return (EINVAL);
		149
		150	m = (mutex_resource_des *)resource_table[mutex->mutexlevel];
		151
		152	return m->trylock(mutex->mutexlevel, mutex);
		153	}
		154
		155	int mutex_unlock(mutex_t *mutex)
		156	{
		157	mutex_resource_des *m;
		158
		159	if (mutex->mutexlevel == -1)
		160	return (EINVAL);
		161
		162	m = (mutex_resource_des *)resource_table[mutex->mutexlevel];
		163
		164	return m->unlock(mutex->mutexlevel, mutex);
		165	}
		166

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