1 /* GNU Objective C Runtime Thread Interface
2 Copyright (C) 1996 Free Software Foundation, Inc.
3 Cobnrtibuted by Galen C. Hunt (gchunt@cs.rochester.edu)
5 This file is part of GNU CC.
7 GNU CC is free software; you can redistribute it and/or modify it under the
8 terms of the GNU General Public License as published by the Free Software
9 Foundation; either version 2, or (at your option) any later version.
11 GNU CC is distributed in the hope that it will be useful, but WITHOUT ANY
12 WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS
13 FOR A PARTICULAR PURPOSE. See the GNU General Public License for more
16 You should have received a copy of the GNU General Public License along with
17 GNU CC; see the file COPYING. If not, write to the Free Software
18 Foundation, 59 Temple Place - Suite 330,
19 Boston, MA 02111-1307, USA. */
21 /* As a special exception, if you link this library with files compiled with
22 GCC to produce an executable, this does not cause the resulting executable
23 to be covered by the GNU General Public License. This exception does not
24 however invalidate any other reasons why the executable file might be
25 covered by the GNU General Public License. */
34 * This structure represents a single mutual exclusion lock. Lock semantics
35 * are detailed with the subsequent functions. We use whatever lock is
36 * provided by the system. We augment it with depth and current owner id
37 * fields to implement and re-entrant lock.
41 volatile _objc_thread_t owner; /* Id of thread that owns. */
42 volatile int depth; /* # of acquires. */
43 mutex_t lock; /* System mutex. */
46 /*****************************************************************************
49 static thread_key_t __objc_thread_data_key; /* Data key for thread data.*/
52 * Initialize the threads subsystem. Returns 0 if successful, or -1 if no
53 * thread support is available.
56 __objc_init_thread_system(void)
58 DEBUG_PRINTF("__objc_init_thread_system\n");
60 if (thr_keycreate(&__objc_thread_data_key, NULL) == 0)
61 return 0; /* Yes, return success. */
63 return -1; /* Failed. */
67 __objc_fini_thread_system(void)
73 * Create a new thread of execution and return its id. Return -1 if fails.
74 * The new thread starts in "func" with the given argument.
77 objc_thread_create(void (*func)(void *arg), void *arg)
79 _objc_thread_t thread_id = NULL; /* Detached thread id. */
80 thread_t new_thread_id = 0; /* Solaris thread id type. */
83 objc_mutex_lock(__objc_runtime_mutex);
85 if (thr_create(NULL, 0, (void *)func, arg,
86 THR_DETACHED | THR_NEW_LWP,
87 &new_thread_id) == 0) { /* Created new thread? */
88 thread_id = (_objc_thread_t)new_thread_id; /* Yes, remember its id. */
89 __objc_runtime_threads_alive++;
92 objc_mutex_unlock(__objc_runtime_mutex);
98 * Set the current thread's priority.
101 objc_thread_set_priority(int priority)
103 int sys_priority = 0;
106 case OBJC_THREAD_INTERACTIVE_PRIORITY:
110 case OBJC_THREAD_BACKGROUND_PRIORITY:
113 case OBJC_THREAD_LOW_PRIORITY:
118 if (thr_setprio(thr_self(), sys_priority) == 0)
119 return 0; /* Changed priority. End. */
121 return -1; /* Failed. */
125 * Return the current thread's priority.
128 objc_thread_get_priority(void)
130 int sys_priority; /* Solaris thread priority. */
132 if (thr_getprio(thr_self(), &sys_priority) == 0) {
133 if (sys_priority >= 250)
134 return OBJC_THREAD_INTERACTIVE_PRIORITY;
135 else if (sys_priority >= 150)
136 return OBJC_THREAD_BACKGROUND_PRIORITY;
137 return OBJC_THREAD_LOW_PRIORITY;
140 return -1; /* Couldn't get priority. */
144 * Yield our process time to another thread. Any BUSY waiting that is done
145 * by a thread should use this function to make sure that other threads can
146 * make progress even on a lazy uniprocessor system.
149 objc_thread_yield(void)
151 thr_yield(); /* Yield to equal thread. */
155 * Terminate the current tread. Doesn't return anything. Doesn't return.
156 * Actually, if it failed returns -1.
159 objc_thread_exit(void)
161 objc_mutex_lock(__objc_runtime_mutex);
162 __objc_runtime_threads_alive++;
163 objc_mutex_unlock(__objc_runtime_mutex);
165 thr_exit(&__objc_thread_exit_status); /* Terminate thread. */
170 * Returns an integer value which uniquely describes a thread. Must not be
171 * NULL which is reserved as a marker for "no thread".
176 return (_objc_thread_t)thr_self();
180 * Sets the thread's local storage pointer. Returns 0 if successful or -1
184 objc_thread_set_data(void *value)
186 if (thr_setspecific(__objc_thread_data_key, value) == 0)
192 * Returns the thread's local storage pointer. Returns NULL on failure.
195 objc_thread_get_data(void)
199 if (thr_getspecific(__objc_thread_data_key, &value) == 0)
200 return value; /* Return thread data. */
206 * Allocate a mutex. Return the mutex pointer if successful or NULL if
207 * the allocation fails for any reason.
210 objc_mutex_allocate(void)
212 struct _objc_mutex *mutex;
215 if (!(mutex = (_objc_mutex_t)__objc_xmalloc(sizeof(struct _objc_mutex))))
216 return NULL; /* Abort if malloc failed. */
218 err = mutex_init(&mutex->lock, USYNC_THREAD, 0);
220 if (err != 0) { /* System init failed? */
221 free(mutex); /* Yes, free local memory. */
222 return NULL; /* Abort. */
224 mutex->owner = NULL; /* No owner. */
225 mutex->depth = 0; /* No locks. */
226 return mutex; /* Return mutex handle. */
230 * Deallocate a mutex. Note that this includes an implicit mutex_lock to
231 * insure that no one else is using the lock. It is legal to deallocate
232 * a lock if we have a lock on it, but illegal to deallotcate a lock held
234 * Returns the number of locks on the thread. (1 for deallocate).
237 objc_mutex_deallocate(_objc_mutex_t mutex)
239 int depth; /* # of locks on mutex. */
241 if (!mutex) /* Is argument bad? */
242 return -1; /* Yes, abort. */
243 depth = objc_mutex_lock(mutex); /* Must have lock. */
245 mutex_destroy(&mutex->lock); /* System deallocate. */
247 free(mutex); /* Free memory. */
248 return depth; /* Return last depth. */
252 * Grab a lock on a mutex. If this thread already has a lock on this mutex
253 * then we increment the lock count. If another thread has a lock on the
254 * mutex we block and wait for the thread to release the lock.
255 * Returns the lock count on the mutex held by this thread.
258 objc_mutex_lock(_objc_mutex_t mutex)
260 _objc_thread_t thread_id; /* Cache our thread id. */
262 if (!mutex) /* Is argument bad? */
263 return -1; /* Yes, abort. */
264 thread_id = objc_thread_id(); /* Get this thread's id. */
265 if (mutex->owner == thread_id) /* Already own lock? */
266 return ++mutex->depth; /* Yes, increment depth. */
268 if (mutex_lock(&mutex->lock) != 0) /* Did lock acquire fail? */
269 return -1; /* Yes, abort. */
271 mutex->owner = thread_id; /* Mark thread as owner. */
272 return mutex->depth = 1; /* Increment depth to end. */
276 * Try to grab a lock on a mutex. If this thread already has a lock on
277 * this mutex then we increment the lock count and return it. If another
278 * thread has a lock on the mutex returns -1.
281 objc_mutex_trylock(_objc_mutex_t mutex)
283 _objc_thread_t thread_id; /* Cache our thread id. */
285 if (!mutex) /* Is argument bad? */
286 return -1; /* Yes, abort. */
287 thread_id = objc_thread_id(); /* Get this thread's id. */
288 if (mutex->owner == thread_id) /* Already own lock? */
289 return ++mutex->depth; /* Yes, increment depth. */
291 if (mutex_trylock(&mutex->lock) != 0) /* Did lock acquire fail? */
292 return -1; /* Yes, abort. */
294 mutex->owner = thread_id; /* Mark thread as owner. */
295 return mutex->depth = 1; /* Increment depth to end. */
299 * Decrements the lock count on this mutex by one. If the lock count reaches
300 * zero, release the lock on the mutex. Returns the lock count on the mutex.
301 * It is an error to attempt to unlock a mutex which this thread doesn't hold
302 * in which case return -1 and the mutex is unaffected.
303 * Will also return -1 if the mutex free fails.
306 objc_mutex_unlock(_objc_mutex_t mutex)
308 _objc_thread_t thread_id; /* Cache our thread id. */
310 if (!mutex) /* Is argument bad? */
311 return -1; /* Yes, abort. */
312 thread_id = objc_thread_id(); /* Get this thread's id. */
313 if (mutex->owner != thread_id) /* Does some else own lock? */
314 return -1; /* Yes, abort. */
315 if (mutex->depth > 1) /* Released last lock? */
316 return --mutex->depth; /* No, Decrement depth, end.*/
317 mutex->depth = 0; /* Yes, reset depth to 0. */
318 mutex->owner = NULL; /* Set owner to "no thread".*/
320 if (mutex_unlock(&mutex->lock) != 0) /* Did lock release fail? */
321 return -1; /* Yes, return error value. */
323 return 0; /* No, return success. */