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_configuration_parameters.h"
63 #include "fosa_mutexes_and_condvars.h"
65 #ifdef OMK_FOR_USER /* If compiled by OMK, use the config */
66 #include "fosa_config.h"
69 /*******************************************************
70 * Mutexes with priority/bandwidth inheritance
71 ******************************************************/
76 * Initialize a frsh mutex
78 * The mutex pointed to by mutex is initialized as a mutex using
79 * the priority ceiling protocol. A priority ceiling of prioceiling
80 * is assigned to this mutex.
82 * Returns 0 if successful; otherwise it returns an error code:
83 * EINVAL: the value of prioceiling is invalid
84 * EAGAIN: the system lacked the necessary resources to create the mutex
85 * ENOMEM: Insufficient memory exists to initialize the mutex
86 * EBUSY: The system has detected an attempt to reinitialize the mutex
88 int fosa_mutex_init(fosa_mutex_t *mutex, int prioceiling)
91 pthread_mutexattr_t attr;
93 ret = pthread_mutexattr_init(&attr);
94 if (ret) return errno;
96 #ifndef CONFIG_NO_PRIO_INHERIT /* Valgrind doesn't support this attribute */
97 ret = pthread_mutexattr_setprotocol(&attr, PTHREAD_PRIO_INHERIT);
98 if (ret) return errno;
101 ret = pthread_mutexattr_setpshared(&attr, PTHREAD_PROCESS_SHARED);
102 if (ret) return errno;
104 return pthread_mutex_init(mutex, &attr);
108 * fosa_mutex_destroy()
110 * Destroy a frsh mutex
112 * The mutex pointed to by mutex is destroyed
114 * Returns 0 if successful; otherwise it returns an error code:
115 * EINVAL: the value of mutex is invalid
116 * EBUSY: The mutex is in use (is locked)
118 int fosa_mutex_destroy(fosa_mutex_t *mutex)
120 return pthread_mutex_destroy(mutex);
124 * fosa_mutex_set_prioceiling()
126 * Dynamically set the priority ceiling of a mutex
128 * Since in this implementation we use BandWidth Inheritance defining the
129 * ceiling of a mutex is meaningless, and so the function always returns
132 int fosa_mutex_set_prioceiling(fosa_mutex_t *mutex,
140 * fosa_mutex_get_prioceiling()
142 * Dynamically get the priority ceiling of a mutex
144 * Since in this implementation we use BandWidth Inheritance defining the
145 * ceiling of a mutex is meaningless, and so the function always returns
148 int fosa_mutex_get_prioceiling(const fosa_mutex_t *mutex, int *ceiling)
158 * This function locks the mutex specified by mutex. If it is already
159 * locked, the calling thread blocks until the mutex becomes
160 * available. The operation returns with the mutex in the locked
161 * state, with the calling thread as its owner.
163 * Returns 0 if successful; otherwise it returns an error code:
164 * EINVAL: the value of mutex is invalid, or the priority of the
165 * calling thread is higher than the priority ceiling of the mutex
166 * EDEADLK: the current thread already owns this mutex
168 int fosa_mutex_lock(fosa_mutex_t *mutex)
170 return pthread_mutex_lock(mutex);
174 * fosa_mutex_trylock()
176 * Try locking a mutex
178 * This function is identical to fosa_mutex_lock() except that if the
179 * mutex is already locked the call returns immediately with an error
182 * Returns 0 if successful; otherwise it returns an error code:
183 * EINVAL: the value of mutex is invalid, or the priority of the
184 * calling thread is higher than the priority ceiling of the mutex
185 * EBUSY: the mutex was already locked
187 int fosa_mutex_trylock(fosa_mutex_t *mutex)
189 return pthread_mutex_trylock(mutex);
193 * fosa_mutex_unlock()
197 * This function must be called by the owner of the mutex referenced
198 * by mutex, to unlock it. If there are threads blocked on the mutex
199 * the mutex becomes available and the highest priority thread is
200 * awakened to acquire the mutex.
202 * Returns 0 if successful; otherwise it returns an error code:
203 * EINVAL: the value of mutex is invalid
204 * EPERM: the calling thread is not the owner of the mutex
206 int fosa_mutex_unlock(fosa_mutex_t *mutex)
208 return pthread_mutex_unlock(mutex);
211 /**********************
212 * Condition variables
213 *********************/
218 * Initiatize a condition variable
220 * The condition variable referenced by cond is initialized with
221 * the attributes required by the FOSA implementation.
223 * Returns 0 if successful; otherwise it returns an error code:
224 * EAGAIN: the system lacked the necessary resources to create the
226 * ENOMEM: Insufficient memory exists to initialize the condition variable
227 * EBUSY: The system has detected an attempt to reinitialize the
230 int fosa_cond_init(fosa_cond_t *cond)
233 pthread_condattr_t attr;
235 ret = pthread_condattr_init(&attr);
236 if (ret) return errno;
238 ret = pthread_condattr_setpshared(&attr, PTHREAD_PROCESS_SHARED);
239 if (ret) return errno;
241 return pthread_cond_init(cond, &attr);
245 * fosa_cond_destroy()
247 * Destroy a condition variable
249 * The condition variable pointed to by cond is destroyed
251 * Returns 0 if successful; otherwise it returns an error code:
252 * EINVAL: the value of cond is invalid
253 * EBUSY: The condition variable is in use (a thread is waiting on it)
255 int fosa_cond_destroy(fosa_cond_t *cond)
257 return pthread_cond_destroy(cond);
263 * Signal a condition variable
265 * This call unblocks at least one of the threads that are waiting on
266 * the condition variable referenced by cond. If there are no threads
267 * waiting, the function has no effect
269 * Returns 0 if successful; otherwise it returns an error code:
270 * EINVAL: the value of cond is invalid
272 int fosa_cond_signal(fosa_cond_t *cond)
274 return pthread_cond_signal(cond);
278 * fosa_cond_broadcast()
280 * Broadcast a condition variable
282 * This call unblocks all of the threads that are waiting on the
283 * condition variable referenced by cond. If there are no threads
284 * waiting, the function has no effect.
286 * Returns 0 if successful; otherwise it returns an error code:
287 * EINVAL: the value of cond is invalid
289 int fosa_cond_broadcast(fosa_cond_t *cond)
291 return pthread_cond_broadcast(cond);
297 * Wait at a condition variable
299 * This call is used to block on the condition variable referenced by
300 * cond. It shall be called with the mutex referenced by mutex
301 * locked. The function releases the mutex and blocks the calling
302 * thread until the condition is signalled by some other thread and
303 * the calling thread is awakened. Then it locks the mutex and
304 * returns with the mutex locked by the calling thread.
306 * Returns 0 if successful; otherwise it returns an error code:
307 * EINVAL: the value of cond or mutex 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
311 int fosa_cond_wait(fosa_cond_t *cond, fosa_mutex_t *mutex)
313 return pthread_cond_wait(cond, mutex);
317 * fosa_cond_timedwait()
319 * Wait at a condition variable, with a timeout
321 * This function is equal to fosa_cond_wait(), except that the maximum
322 * wait time is limited to the absolute time referenced by abstime, as
323 * measured by the FOSA_CLOCK_ABSOLUTE clock.
325 * Returns 0 if successful; otherwise it returns an error code:
326 * EINVAL: the value of cond or mutex or abstime is invalid, or different
327 * mutexes were used for concurrent wait operations on cond, or
328 * the mutex was not owned by the calling thread
329 * ETIMEDOUT: the timeout expired
331 int fosa_cond_timedwait(fosa_cond_t *cond,
333 const fosa_abs_time_t *abstime)
335 struct timespec abstime_tspec;
337 abstime_tspec = fosa_abs_time_to_timespec(*abstime);
338 return pthread_cond_timedwait(cond, mutex, &abstime_tspec);