1 // -----------------------------------------------------------------------
2 // Copyright (C) 2006 - 2007 FRESCOR consortium partners:
4 // Universidad de Cantabria, SPAIN
5 // University of York, UK
6 // Scuola Superiore Sant'Anna, ITALY
7 // Kaiserslautern University, GERMANY
8 // Univ. Politecnica Valencia, SPAIN
9 // Czech Technical University in Prague, CZECH REPUBLIC
11 // Thales Communication S.A. FRANCE
12 // Visual Tools S.A. SPAIN
13 // Rapita Systems Ltd UK
16 // See http://www.frescor.org for a link to partners' websites
18 // FRESCOR project (FP6/2005/IST/5-034026) is funded
19 // in part by the European Union Sixth Framework Programme
20 // The European Union is not liable of any use that may be
23 // This file is part of the FRSH implementation
25 // FRSH is free software; you can redistribute it and/or modify
26 // it under the terms of the GNU General Public License as published by
27 // the Free Software Foundation; either version 2, or (at your option)
30 // FRSH is distributed in the hope that it will be useful, but
31 // WITHOUT ANY WARRANTY; without even the implied warranty of
32 // MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
33 // General Public License for more details.
35 // You should have received a copy of the GNU General Public License
36 // distributed with FRSH; see file COPYING. If not, write to the
37 // Free Software Foundation, 59 Temple Place - Suite 330, Boston, MA
40 // As a special exception, if you include this header file into source
41 // files to be compiled, this header file does not by itself cause
42 // the resulting executable to be covered by the GNU General Public
43 // License. This exception does not however invalidate any other
44 // reasons why the executable file might be covered by the GNU General
46 // -----------------------------------------------------------------------
47 //fosa_mutexes_and_condvars.h
48 //==============================================
49 // ******** ****** ******** **********
50 // **///// /** ** **////// /** /**
51 // ** /** ** /** /** /**
52 // ******* /** ** /********* /**********
53 // **//// /** ** ////////** /**//////**
54 // ** /** ** /** /** /**
55 // ** /** ** ******** /** /**
56 // // /******/ //////// // //
58 // FOSA(Frescor Operating System Adaptation layer)
59 //================================================
61 #include "fosa_mutexes_and_condvars.h"
63 /*******************************************************
64 * Mutexes with priority/bandwidth inheritance
65 ******************************************************/
70 * Initialize a frsh mutex
72 * The mutex pointed to by mutex is initialized as a mutex using
73 * the priority ceiling protocol. A priority ceiling of prioceiling
74 * is assigned to this mutex.
76 * Returns 0 if successful; otherwise it returns an error code:
77 * EINVAL: the value of prioceiling is invalid
78 * EAGAIN: the system lacked the necessary resources to create the mutex
79 * ENOMEM: Insufficient memory exists to initialize the mutex
80 * EBUSY: The system has detected an attempt to reinitialize the mutex
82 int fosa_mutex_init(fosa_mutex_t *mutex, int prioceiling)
85 pthread_mutexattr_t attr;
87 if ((error = pthread_mutexattr_init(&attr)) != 0)
90 if ((error = pthread_mutexattr_setprotocol(&attr, PTHREAD_PRIO_INHERIT)) != 0)
93 return pthread_mutex_init(mutex, &attr);
97 * fosa_mutex_destroy()
99 * Destroy a frsh mutex
101 * The mutex pointed to by mutex is destroyed
103 * Returns 0 if successful; otherwise it returns an error code:
104 * EINVAL: the value of mutex is invalid
105 * EBUSY: The mutex is in use (is locked)
107 int fosa_mutex_destroy(fosa_mutex_t *mutex)
109 return pthread_mutex_destroy(mutex);
113 * fosa_mutex_set_prioceiling()
115 * Dynamically set the priority ceiling of a mutex
117 * Since in this implementation we use BandWidth Inheritance defining the
118 * ceiling of a mutex is meaningless, and so the function always returns
121 int fosa_mutex_set_prioceiling(fosa_mutex_t *mutex,
129 * fosa_mutex_get_prioceiling()
131 * Dynamically get the priority ceiling of a mutex
133 * Since in this implementation we use BandWidth Inheritance defining the
134 * ceiling of a mutex is meaningless, and so the function always returns
137 int fosa_mutex_get_prioceiling(const fosa_mutex_t *mutex, int *ceiling)
147 * This function locks the mutex specified by mutex. If it is already
148 * locked, the calling thread blocks until the mutex becomes
149 * available. The operation returns with the mutex in the locked
150 * state, with the calling thread as its owner.
152 * Returns 0 if successful; otherwise it returns an error code:
153 * EINVAL: the value of mutex is invalid, or the priority of the
154 * calling thread is higher than the priority ceiling of the mutex
155 * EDEADLK: the current thread already owns this mutex
157 int fosa_mutex_lock(fosa_mutex_t *mutex)
159 return pthread_mutex_lock(mutex);
163 * fosa_mutex_trylock()
165 * Try locking a mutex
167 * This function is identical to fosa_mutex_lock() except that if the
168 * mutex is already locked the call returns immediately with an error
171 * Returns 0 if successful; otherwise it returns an error code:
172 * EINVAL: the value of mutex is invalid, or the priority of the
173 * calling thread is higher than the priority ceiling of the mutex
174 * EBUSY: the mutex was already locked
176 int fosa_mutex_trylock(fosa_mutex_t *mutex)
178 return pthread_mutex_trylock(mutex);
182 * fosa_mutex_unlock()
186 * This function must be called by the owner of the mutex referenced
187 * by mutex, to unlock it. If there are threads blocked on the mutex
188 * the mutex becomes available and the highest priority thread is
189 * awakened to acquire the mutex.
191 * Returns 0 if successful; otherwise it returns an error code:
192 * EINVAL: the value of mutex is invalid
193 * EPERM: the calling thread is not the owner of the mutex
195 int fosa_mutex_unlock(fosa_mutex_t *mutex)
197 return pthread_mutex_unlock(mutex);
200 /**********************
201 * Condition variables
202 *********************/
207 * Initiatize a condition variable
209 * The condition variable referenced by cond is initialized with
210 * the attributes required by the FOSA implementation.
212 * Returns 0 if successful; otherwise it returns an error code:
213 * EAGAIN: the system lacked the necessary resources to create the
215 * ENOMEM: Insufficient memory exists to initialize the condition variable
216 * EBUSY: The system has detected an attempt to reinitialize the
219 int fosa_cond_init(fosa_cond_t *cond)
221 return pthread_cond_init(cond, NULL);
225 * fosa_cond_destroy()
227 * Destroy a condition variable
229 * The condition variable pointed to by cond is destroyed
231 * Returns 0 if successful; otherwise it returns an error code:
232 * EINVAL: the value of cond is invalid
233 * EBUSY: The condition variable is in use (a thread is waiting on it)
235 int fosa_cond_destroy(fosa_cond_t *cond)
237 return pthread_cond_destroy(cond);
243 * Signal a condition variable
245 * This call unblocks at least one of the threads that are waiting on
246 * the condition variable referenced by cond. If there are no threads
247 * waiting, the function has no effect
249 * Returns 0 if successful; otherwise it returns an error code:
250 * EINVAL: the value of cond is invalid
252 int fosa_cond_signal(fosa_cond_t *cond)
254 return pthread_cond_signal(cond);
258 * fosa_cond_broadcast()
260 * Broadcast a condition variable
262 * This call unblocks all of the threads that are waiting on the
263 * condition variable referenced by cond. If there are no threads
264 * waiting, the function has no effect.
266 * Returns 0 if successful; otherwise it returns an error code:
267 * EINVAL: the value of cond is invalid
269 int fosa_cond_broadcast(fosa_cond_t *cond)
271 return pthread_cond_broadcast(cond);
277 * Wait at a condition variable
279 * This call is used to block on the condition variable referenced by
280 * cond. It shall be called with the mutex referenced by mutex
281 * locked. The function releases the mutex and blocks the calling
282 * thread until the condition is signalled by some other thread and
283 * the calling thread is awakened. Then it locks the mutex and
284 * returns with the mutex locked by the calling thread.
286 * Returns 0 if successful; otherwise it returns an error code:
287 * EINVAL: the value of cond or mutex is invalid, or different
288 * mutexes were used for concurrent wait operations on cond, or
289 * the mutex was not owned by the calling thread
291 int fosa_cond_wait(fosa_cond_t *cond, fosa_mutex_t *mutex)
293 return pthread_cond_wait(cond, mutex);
297 * fosa_cond_timedwait()
299 * Wait at a condition variable, with a timeout
301 * This function is equal to fosa_cond_wait(), except that the maximum
302 * wait time is limited to the absolute time referenced by abstime, as
303 * measured by the FOSA_CLOCK_ABSOLUTE clock.
305 * Returns 0 if successful; otherwise it returns an error code:
306 * EINVAL: the value of cond or mutex or abstime is invalid, or different
307 * mutexes were used for concurrent wait operations on cond, or
308 * the mutex was not owned by the calling thread
309 * ETIMEDOUT: the timeout expired
311 int fosa_cond_timedwait(fosa_cond_t *cond,
313 const struct timespec *abstime)
315 return pthread_cond_timedwait(cond, mutex, abstime);