WebSVN - shark - Blame - Rev 318 - /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	------------
318	giacomo	21	CVS : $Id: mutex.c,v 1.4 2003-11-05 15:05:12 giacomo Exp $
2	pj	22
		23	File: $File$
318	giacomo	24	Revision: $Revision: 1.4 $
		25	Last update: $Date: 2003-11-05 15:05:12 $
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;
318	giacomo	92	SYS_FLAGS f;
38	pj	93	int result;
2	pj	94
318	giacomo	95	f = kern_fsave();
2	pj	96	mutex->mutexlevel = -1;
		97	mutex->use = 0;
		98
		99	for (l=0; l<res_levels; l++) {
		100	if (resource_table[l]->rtype == MUTEX_RTYPE) {
		101	/* the cast to mutex_resource_des is legal */
		102	mutex_resource_des m = (mutex_resource_des )resource_table[l];
		103
		104	/* can the mutex level manage the mutexattr_t ? */
228	giacomo	105	if ((result = m->init(l, mutex, attr)) >=0) {
318	giacomo	106	kern_frestore(f);
38	pj	107	return result;
228	giacomo	108	}
2	pj	109	}
		110	}
318	giacomo	111	kern_frestore(f);
2	pj	112
38	pj	113	return EINVAL;
2	pj	114	}
		115
		116
		117	int mutex_destroy(mutex_t *mutex)
		118	{
		119	mutex_resource_des *m;
		120
		121	if (mutex->mutexlevel == -1)
		122	return (EINVAL);
		123
		124	if (mutex->use)
		125	return (EBUSY);
		126
		127	m = (mutex_resource_des *)resource_table[mutex->mutexlevel];
		128
		129	return m->destroy(mutex->mutexlevel, mutex);
		130	}
		131
		132	int mutex_lock(mutex_t *mutex)
		133	{
		134	mutex_resource_des *m;
		135
		136	if (mutex->mutexlevel == -1)
		137	return (EINVAL);
		138
		139	m = (mutex_resource_des *)resource_table[mutex->mutexlevel];
		140
		141	return m->lock(mutex->mutexlevel, mutex);
		142	}
		143
		144	int mutex_trylock(mutex_t *mutex)
		145	{
		146	mutex_resource_des *m;
		147
		148	if (mutex->mutexlevel == -1)
		149	return (EINVAL);
		150
		151	m = (mutex_resource_des *)resource_table[mutex->mutexlevel];
		152
		153	return m->trylock(mutex->mutexlevel, mutex);
		154	}
		155
		156	int mutex_unlock(mutex_t *mutex)
		157	{
		158	mutex_resource_des *m;
		159
		160	if (mutex->mutexlevel == -1)
		161	return (EINVAL);
		162
		163	m = (mutex_resource_des *)resource_table[mutex->mutexlevel];
		164
		165	return m->unlock(mutex->mutexlevel, mutex);
		166	}
		167

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