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_time.h"
62 #include "fosa_mutexes_and_condvars.h"
64 /*******************************************************
65 * Mutexes with priority/bandwidth inheritance
66 ******************************************************/
71 * Initialize a frsh mutex
73 * The mutex pointed to by mutex is initialized as a mutex using
74 * the priority ceiling protocol. A priority ceiling of prioceiling
75 * is assigned to this mutex.
77 * Returns 0 if successful; otherwise it returns an error code:
78 * EINVAL: the value of prioceiling is invalid
79 * EAGAIN: the system lacked the necessary resources to create the mutex
80 * ENOMEM: Insufficient memory exists to initialize the mutex
81 * EBUSY: The system has detected an attempt to reinitialize the mutex
83 int fosa_mutex_init(fosa_mutex_t *mutex, int prioceiling)
86 pthread_mutexattr_t attr;
88 if ((error = pthread_mutexattr_init(&attr)) != 0)
91 if ((error = pthread_mutexattr_setprotocol(&attr, PTHREAD_PRIO_INHERIT)) != 0)
94 return pthread_mutex_init(mutex, &attr);
98 * fosa_mutex_destroy()
100 * Destroy a frsh mutex
102 * The mutex pointed to by mutex is destroyed
104 * Returns 0 if successful; otherwise it returns an error code:
105 * EINVAL: the value of mutex is invalid
106 * EBUSY: The mutex is in use (is locked)
108 int fosa_mutex_destroy(fosa_mutex_t *mutex)
110 return pthread_mutex_destroy(mutex);
114 * fosa_mutex_set_prioceiling()
116 * Dynamically set the priority ceiling of a mutex
118 * Since in this implementation we use BandWidth Inheritance defining the
119 * ceiling of a mutex is meaningless, and so the function always returns
122 int fosa_mutex_set_prioceiling(fosa_mutex_t *mutex,
130 * fosa_mutex_get_prioceiling()
132 * Dynamically get the priority ceiling of a mutex
134 * Since in this implementation we use BandWidth Inheritance defining the
135 * ceiling of a mutex is meaningless, and so the function always returns
138 int fosa_mutex_get_prioceiling(const fosa_mutex_t *mutex, int *ceiling)
148 * This function locks the mutex specified by mutex. If it is already
149 * locked, the calling thread blocks until the mutex becomes
150 * available. The operation returns with the mutex in the locked
151 * state, with the calling thread as its owner.
153 * Returns 0 if successful; otherwise it returns an error code:
154 * EINVAL: the value of mutex is invalid, or the priority of the
155 * calling thread is higher than the priority ceiling of the mutex
156 * EDEADLK: the current thread already owns this mutex
158 int fosa_mutex_lock(fosa_mutex_t *mutex)
160 return pthread_mutex_lock(mutex);
164 * fosa_mutex_trylock()
166 * Try locking a mutex
168 * This function is identical to fosa_mutex_lock() except that if the
169 * mutex is already locked the call returns immediately with an error
172 * Returns 0 if successful; otherwise it returns an error code:
173 * EINVAL: the value of mutex is invalid, or the priority of the
174 * calling thread is higher than the priority ceiling of the mutex
175 * EBUSY: the mutex was already locked
177 int fosa_mutex_trylock(fosa_mutex_t *mutex)
179 return pthread_mutex_trylock(mutex);
183 * fosa_mutex_unlock()
187 * This function must be called by the owner of the mutex referenced
188 * by mutex, to unlock it. If there are threads blocked on the mutex
189 * the mutex becomes available and the highest priority thread is
190 * awakened to acquire the mutex.
192 * Returns 0 if successful; otherwise it returns an error code:
193 * EINVAL: the value of mutex is invalid
194 * EPERM: the calling thread is not the owner of the mutex
196 int fosa_mutex_unlock(fosa_mutex_t *mutex)
198 return pthread_mutex_unlock(mutex);
201 /**********************
202 * Condition variables
203 *********************/
208 * Initiatize a condition variable
210 * The condition variable referenced by cond is initialized with
211 * the attributes required by the FOSA implementation.
213 * Returns 0 if successful; otherwise it returns an error code:
214 * EAGAIN: the system lacked the necessary resources to create the
216 * ENOMEM: Insufficient memory exists to initialize the condition variable
217 * EBUSY: The system has detected an attempt to reinitialize the
220 int fosa_cond_init(fosa_cond_t *cond)
222 return pthread_cond_init(cond, NULL);
226 * fosa_cond_destroy()
228 * Destroy a condition variable
230 * The condition variable pointed to by cond is destroyed
232 * Returns 0 if successful; otherwise it returns an error code:
233 * EINVAL: the value of cond is invalid
234 * EBUSY: The condition variable is in use (a thread is waiting on it)
236 int fosa_cond_destroy(fosa_cond_t *cond)
238 return pthread_cond_destroy(cond);
244 * Signal a condition variable
246 * This call unblocks at least one of the threads that are waiting on
247 * the condition variable referenced by cond. If there are no threads
248 * waiting, the function has no effect
250 * Returns 0 if successful; otherwise it returns an error code:
251 * EINVAL: the value of cond is invalid
253 int fosa_cond_signal(fosa_cond_t *cond)
255 return pthread_cond_signal(cond);
259 * fosa_cond_broadcast()
261 * Broadcast a condition variable
263 * This call unblocks all of the threads that are waiting on the
264 * condition variable referenced by cond. If there are no threads
265 * waiting, the function has no effect.
267 * Returns 0 if successful; otherwise it returns an error code:
268 * EINVAL: the value of cond is invalid
270 int fosa_cond_broadcast(fosa_cond_t *cond)
272 return pthread_cond_broadcast(cond);
278 * Wait at a condition variable
280 * This call is used to block on the condition variable referenced by
281 * cond. It shall be called with the mutex referenced by mutex
282 * locked. The function releases the mutex and blocks the calling
283 * thread until the condition is signalled by some other thread and
284 * the calling thread is awakened. Then it locks the mutex and
285 * returns with the mutex locked by the calling thread.
287 * Returns 0 if successful; otherwise it returns an error code:
288 * EINVAL: the value of cond or mutex is invalid, or different
289 * mutexes were used for concurrent wait operations on cond, or
290 * the mutex was not owned by the calling thread
292 int fosa_cond_wait(fosa_cond_t *cond, fosa_mutex_t *mutex)
294 return pthread_cond_wait(cond, mutex);
298 * fosa_cond_timedwait()
300 * Wait at a condition variable, with a timeout
302 * This function is equal to fosa_cond_wait(), except that the maximum
303 * wait time is limited to the absolute time referenced by abstime, as
304 * measured by the FOSA_CLOCK_ABSOLUTE clock.
306 * Returns 0 if successful; otherwise it returns an error code:
307 * EINVAL: the value of cond or mutex or abstime is invalid, or different
308 * mutexes were used for concurrent wait operations on cond, or
309 * the mutex was not owned by the calling thread
310 * ETIMEDOUT: the timeout expired
312 int fosa_cond_timedwait(fosa_cond_t *cond,
314 const fosa_abs_time_t *abstime)
316 struct timespec abstime_tspec;
318 abstime_tspec = fosa_abs_time_to_timespec(*abstime);
320 return pthread_cond_timedwait(cond, mutex, &abstime_tspec);