1 /* GNU Objective C Runtime Thread Interface
2 Copyright (C) 1996 Free Software Foundation, Inc.
3 Contributed 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. */
35 * This structure represents a single mutual exclusion lock. Lock semantics
36 * are detailed with the subsequent functions. We use whatever lock is
37 * provided by the system. We augment it with depth and current owner id
38 * fields to implement and re-entrant lock.
42 volatile _objc_thread_t owner; /* Id of thread that owns. */
43 volatile int depth; /* # of acquires. */
44 mutex_t lock; /* System mutex. */
47 /*****************************************************************************
50 static thread_key_t __objc_thread_data_key; /* Data key for thread data.*/
53 * Initialize the threads subsystem. Returns 0 if successful, or -1 if no
54 * thread support is available.
57 __objc_init_thread_system(void)
59 DEBUG_PRINTF("__objc_init_thread_system\n");
61 if (thr_keycreate(&__objc_thread_data_key, NULL) == 0)
62 return 0; /* Yes, return success. */
64 return -1; /* Failed. */
68 __objc_fini_thread_system(void)
74 * Create a new thread of execution and return its id. Return -1 if fails.
75 * The new thread starts in "func" with the given argument.
78 objc_thread_create(void (*func)(void *arg), void *arg)
80 _objc_thread_t thread_id = NULL; /* Detached thread id. */
81 thread_t new_thread_id = 0; /* Solaris thread id type. */
84 objc_mutex_lock(__objc_runtime_mutex);
86 if (thr_create(NULL, 0, (void *)func, arg,
87 THR_DETACHED | THR_NEW_LWP,
88 &new_thread_id) == 0) { /* Created new thread? */
89 thread_id = (_objc_thread_t)new_thread_id; /* Yes, remember its id. */
90 __objc_runtime_threads_alive++;
93 objc_mutex_unlock(__objc_runtime_mutex);
99 * Set the current thread's priority.
102 objc_thread_set_priority(int priority)
104 int sys_priority = 0;
107 case OBJC_THREAD_INTERACTIVE_PRIORITY:
111 case OBJC_THREAD_BACKGROUND_PRIORITY:
114 case OBJC_THREAD_LOW_PRIORITY:
119 if (thr_setprio(thr_self(), sys_priority) == 0)
120 return 0; /* Changed priority. End. */
122 return -1; /* Failed. */
126 * Return the current thread's priority.
129 objc_thread_get_priority(void)
131 int sys_priority; /* Solaris thread priority. */
133 if (thr_getprio(thr_self(), &sys_priority) == 0) {
134 if (sys_priority >= 250)
135 return OBJC_THREAD_INTERACTIVE_PRIORITY;
136 else if (sys_priority >= 150)
137 return OBJC_THREAD_BACKGROUND_PRIORITY;
138 return OBJC_THREAD_LOW_PRIORITY;
141 return -1; /* Couldn't get priority. */
145 * Yield our process time to another thread. Any BUSY waiting that is done
146 * by a thread should use this function to make sure that other threads can
147 * make progress even on a lazy uniprocessor system.
150 objc_thread_yield(void)
152 thr_yield(); /* Yield to equal thread. */
156 * Terminate the current tread. Doesn't return anything. Doesn't return.
157 * Actually, if it failed returns -1.
160 objc_thread_exit(void)
162 objc_mutex_lock(__objc_runtime_mutex);
163 __objc_runtime_threads_alive++;
164 objc_mutex_unlock(__objc_runtime_mutex);
166 thr_exit(&__objc_thread_exit_status); /* Terminate thread. */
171 * Returns an integer value which uniquely describes a thread. Must not be
172 * NULL which is reserved as a marker for "no thread".
177 return (_objc_thread_t)thr_self();
181 * Sets the thread's local storage pointer. Returns 0 if successful or -1
185 objc_thread_set_data(void *value)
187 if (thr_setspecific(__objc_thread_data_key, value) == 0)
193 * Returns the thread's local storage pointer. Returns NULL on failure.
196 objc_thread_get_data(void)
200 if (thr_getspecific(__objc_thread_data_key, &value) == 0)
201 return value; /* Return thread data. */
207 * Allocate a mutex. Return the mutex pointer if successful or NULL if
208 * the allocation fails for any reason.
211 objc_mutex_allocate(void)
213 struct _objc_mutex *mutex;
216 if (!(mutex = (_objc_mutex_t)__objc_xmalloc(sizeof(struct _objc_mutex))))
217 return NULL; /* Abort if malloc failed. */
219 err = mutex_init(&mutex->lock, USYNC_THREAD, 0);
221 if (err != 0) { /* System init failed? */
222 free(mutex); /* Yes, free local memory. */
223 return NULL; /* Abort. */
225 mutex->owner = NULL; /* No owner. */
226 mutex->depth = 0; /* No locks. */
227 return mutex; /* Return mutex handle. */
231 * Deallocate a mutex. Note that this includes an implicit mutex_lock to
232 * insure that no one else is using the lock. It is legal to deallocate
233 * a lock if we have a lock on it, but illegal to deallotcate a lock held
235 * Returns the number of locks on the thread. (1 for deallocate).
238 objc_mutex_deallocate(_objc_mutex_t mutex)
240 int depth; /* # of locks on mutex. */
242 if (!mutex) /* Is argument bad? */
243 return -1; /* Yes, abort. */
244 depth = objc_mutex_lock(mutex); /* Must have lock. */
246 mutex_destroy(&mutex->lock); /* System deallocate. */
248 free(mutex); /* Free memory. */
249 return depth; /* Return last depth. */
253 * Grab a lock on a mutex. If this thread already has a lock on this mutex
254 * then we increment the lock count. If another thread has a lock on the
255 * mutex we block and wait for the thread to release the lock.
256 * Returns the lock count on the mutex held by this thread.
259 objc_mutex_lock(_objc_mutex_t mutex)
261 _objc_thread_t thread_id; /* Cache our thread id. */
263 if (!mutex) /* Is argument bad? */
264 return -1; /* Yes, abort. */
265 thread_id = objc_thread_id(); /* Get this thread's id. */
266 if (mutex->owner == thread_id) /* Already own lock? */
267 return ++mutex->depth; /* Yes, increment depth. */
269 if (mutex_lock(&mutex->lock) != 0) /* Did lock acquire fail? */
270 return -1; /* Yes, abort. */
272 mutex->owner = thread_id; /* Mark thread as owner. */
273 return mutex->depth = 1; /* Increment depth to end. */
277 * Try to grab a lock on a mutex. If this thread already has a lock on
278 * this mutex then we increment the lock count and return it. If another
279 * thread has a lock on the mutex returns -1.
282 objc_mutex_trylock(_objc_mutex_t mutex)
284 _objc_thread_t thread_id; /* Cache our thread id. */
286 if (!mutex) /* Is argument bad? */
287 return -1; /* Yes, abort. */
288 thread_id = objc_thread_id(); /* Get this thread's id. */
289 if (mutex->owner == thread_id) /* Already own lock? */
290 return ++mutex->depth; /* Yes, increment depth. */
292 if (mutex_trylock(&mutex->lock) != 0) /* Did lock acquire fail? */
293 return -1; /* Yes, abort. */
295 mutex->owner = thread_id; /* Mark thread as owner. */
296 return mutex->depth = 1; /* Increment depth to end. */
300 * Decrements the lock count on this mutex by one. If the lock count reaches
301 * zero, release the lock on the mutex. Returns the lock count on the mutex.
302 * It is an error to attempt to unlock a mutex which this thread doesn't hold
303 * in which case return -1 and the mutex is unaffected.
304 * Will also return -1 if the mutex free fails.
307 objc_mutex_unlock(_objc_mutex_t mutex)
309 _objc_thread_t thread_id; /* Cache our thread id. */
311 if (!mutex) /* Is argument bad? */
312 return -1; /* Yes, abort. */
313 thread_id = objc_thread_id(); /* Get this thread's id. */
314 if (mutex->owner != thread_id) /* Does some else own lock? */
315 return -1; /* Yes, abort. */
316 if (mutex->depth > 1) /* Released last lock? */
317 return --mutex->depth; /* No, Decrement depth, end.*/
318 mutex->depth = 0; /* Yes, reset depth to 0. */
319 mutex->owner = NULL; /* Set owner to "no thread".*/
321 if (mutex_unlock(&mutex->lock) != 0) /* Did lock release fail? */
322 return -1; /* Yes, return error value. */
324 return 0; /* No, return success. */