libobjc/thr-mach.c

   1 /* GNU Objective C Runtime Thread Implementation
   2    Copyright (C) 1996, 1997, 2002, 2009 Free Software Foundation, Inc.
   3    Contributed by Galen C. Hunt (gchunt@cs.rochester.edu)
   4    Modified for Mach threads by Bill Bumgarner <bbum@friday.com>
   5    Condition functions added by Mircea Oancea <mircea@first.elcom.pub.ro>
   6
   7 This file is part of GCC.
   8
   9 GCC is free software; you can redistribute it and/or modify it under the
  10 terms of the GNU General Public License as published by the Free Software
  11 Foundation; either version 3, or (at your option) any later version.
  12
  13 GCC is distributed in the hope that it will be useful, but WITHOUT ANY
  14 WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS
  15 FOR A PARTICULAR PURPOSE.  See the GNU General Public License for more
  16 details.
  17
  18 Under Section 7 of GPL version 3, you are granted additional
  19 permissions described in the GCC Runtime Library Exception, version
  20 3.1, as published by the Free Software Foundation.
  21
  22 You should have received a copy of the GNU General Public License and
  23 a copy of the GCC Runtime Library Exception along with this program;
  24 see the files COPYING3 and COPYING.RUNTIME respectively.  If not, see
  25 <http://www.gnu.org/licenses/>.  */
  26
  27
  28 #include <mach/mach.h>
  29 #include <mach/cthreads.h>
  30 #include "objc/thr.h"
  31 #include "objc/runtime.h"
  32
  33 /*
  34   Obtain the maximum thread priority that can set for t.  Under the
  35   mach threading model, it is possible for the developer to adjust the
  36   maximum priority downward only-- cannot be raised without superuser
  37   privileges.  Once lowered, it cannot be raised.
  38   */
  39 static int
  40 __mach_get_max_thread_priority (cthread_t t, int *base)
  41 {
  42   thread_t threadP;
  43   kern_return_t error;
  44   struct thread_sched_info info;
  45   unsigned int info_count=THREAD_SCHED_INFO_COUNT;
  46
  47   if (t == NULL)
  48     return -1;
  49
  50   threadP  = cthread_thread (t);        /* get thread underlying */
  51
  52   error = thread_info (threadP, THREAD_SCHED_INFO,
  53                        (thread_info_t) &info, &info_count);
  54
  55   if (error != KERN_SUCCESS)
  56     return -1;
  57
  58   if (base != NULL)
  59     *base = info.base_priority;
  60
  61   return info.max_priority;
  62 }
  63
  64 /* Backend initialization functions */
  65
  66 /* Initialize the threads subsystem. */
  67 int
  68 __objc_init_thread_system (void)
  69 {
  70   return 0;
  71 }
  72
  73 /* Close the threads subsystem. */
  74 int
  75 __objc_close_thread_system (void)
  76 {
  77   return 0;
  78 }
  79
  80 /* Backend thread functions */
  81
  82 /* Create a new thread of execution. */
  83 objc_thread_t
  84 __objc_thread_detach (void (*func) (void *arg), void *arg)
  85 {
  86   objc_thread_t thread_id;
  87   cthread_t new_thread_handle;
  88
  89   /* create thread */
  90   new_thread_handle = cthread_fork ((cthread_fn_t) func, arg);
  91
  92   if (new_thread_handle)
  93     {
  94       /* this is not terribly portable */
  95       thread_id = *(objc_thread_t *) &new_thread_handle;
  96       cthread_detach (new_thread_handle);
  97     }
  98   else
  99     thread_id = NULL;
 100
 101   return thread_id;
 102 }
 103
 104 /* Set the current thread's priority. */
 105 int
 106 __objc_thread_set_priority (int priority)
 107 {
 108   objc_thread_t *t = objc_thread_id ();
 109   cthread_t cT = (cthread_t) t;
 110   int maxPriority = __mach_get_max_thread_priority (cT, NULL);
 111   int sys_priority = 0;
 112
 113   if (maxPriority == -1)
 114     return -1;
 115
 116   switch (priority)
 117     {
 118     case OBJC_THREAD_INTERACTIVE_PRIORITY:
 119       sys_priority = maxPriority;
 120       break;
 121     case OBJC_THREAD_BACKGROUND_PRIORITY:
 122       sys_priority = (maxPriority * 2) / 3;
 123       break;
 124     case OBJC_THREAD_LOW_PRIORITY:
 125       sys_priority = maxPriority / 3;
 126       break;
 127     default:
 128       return -1;
 129     }
 130
 131   if (sys_priority == 0)
 132     return -1;
 133
 134   /* Change the priority */
 135   if (cthread_priority (cT, sys_priority, 0) == KERN_SUCCESS)
 136     return 0;
 137   else
 138     return -1;
 139 }
 140
 141 /* Return the current thread's priority. */
 142 int
 143 __objc_thread_get_priority (void)
 144 {
 145   objc_thread_t *t = objc_thread_id ();
 146   cthread_t cT = (cthread_t) t; /* see objc_thread_id () */
 147   int basePriority;
 148   int maxPriority;
 149   int sys_priority = 0;
 150
 151   int interactiveT, backgroundT, lowT; /* thresholds */
 152
 153   maxPriority = __mach_get_max_thread_priority (cT, &basePriority);
 154
 155   if (maxPriority == -1)
 156     return -1;
 157
 158   if (basePriority > ( (maxPriority * 2) / 3))
 159     return OBJC_THREAD_INTERACTIVE_PRIORITY;
 160
 161   if (basePriority > ( maxPriority / 3))
 162     return OBJC_THREAD_BACKGROUND_PRIORITY;
 163
 164   return OBJC_THREAD_LOW_PRIORITY;
 165 }
 166
 167 /* Yield our process time to another thread. */
 168 void
 169 __objc_thread_yield (void)
 170 {
 171   cthread_yield ();
 172 }
 173
 174 /* Terminate the current thread. */
 175 int
 176 __objc_thread_exit (void)
 177 {
 178   /* exit the thread */
 179   cthread_exit (&__objc_thread_exit_status);
 180
 181   /* Failed if we reached here */
 182   return -1;
 183 }
 184
 185 /* Returns an integer value which uniquely describes a thread. */
 186 objc_thread_t
 187 __objc_thread_id (void)
 188 {
 189   cthread_t self = cthread_self ();
 190
 191   return *(objc_thread_t *) &self;
 192 }
 193
 194 /* Sets the thread's local storage pointer. */
 195 int
 196 __objc_thread_set_data (void *value)
 197 {
 198   cthread_set_data (cthread_self (), (any_t) value);
 199   return 0;
 200 }
 201
 202 /* Returns the thread's local storage pointer. */
 203 void *
 204 __objc_thread_get_data (void)
 205 {
 206   return (void *) cthread_data (cthread_self ());
 207 }
 208
 209 /* Backend mutex functions */
 210
 211 /* Allocate a mutex. */
 212 int
 213 __objc_mutex_allocate (objc_mutex_t mutex)
 214 {
 215   int err = 0;
 216   mutex->backend = objc_malloc (sizeof (struct mutex));
 217
 218   err = mutex_init ((mutex_t) (mutex->backend));
 219
 220   if (err != 0)
 221     {
 222       objc_free (mutex->backend);
 223       return -1;
 224     }
 225   else
 226     return 0;
 227 }
 228
 229 /* Deallocate a mutex. */
 230 int
 231 __objc_mutex_deallocate (objc_mutex_t mutex)
 232 {
 233   mutex_clear ((mutex_t) (mutex->backend));
 234
 235   objc_free (mutex->backend);
 236   mutex->backend = NULL;
 237   return 0;
 238 }
 239
 240 /* Grab a lock on a mutex. */
 241 int
 242 __objc_mutex_lock (objc_mutex_t mutex)
 243 {
 244   mutex_lock ((mutex_t) (mutex->backend));
 245   return 0;
 246 }
 247
 248 /* Try to grab a lock on a mutex. */
 249 int
 250 __objc_mutex_trylock (objc_mutex_t mutex)
 251 {
 252   if (mutex_try_lock ((mutex_t) (mutex->backend)) == 0)
 253     return -1;
 254   else
 255     return 0;
 256 }
 257
 258 /* Unlock the mutex */
 259 int
 260 __objc_mutex_unlock (objc_mutex_t mutex)
 261 {
 262   mutex_unlock ((mutex_t) (mutex->backend));
 263   return 0;
 264 }
 265
 266 /* Backend condition mutex functions */
 267
 268 /* Allocate a condition. */
 269 int
 270 __objc_condition_allocate (objc_condition_t condition)
 271 {
 272   condition->backend = objc_malloc (sizeof (struct condition));
 273   condition_init ((condition_t) (condition->backend));
 274   return 0;
 275 }
 276
 277 /* Deallocate a condition. */
 278 int
 279 __objc_condition_deallocate (objc_condition_t condition)
 280 {
 281   condition_clear ((condition_t) (condition->backend));
 282   objc_free (condition->backend);
 283   condition->backend = NULL;
 284   return 0;
 285 }
 286
 287 /* Wait on the condition */
 288 int
 289 __objc_condition_wait (objc_condition_t condition, objc_mutex_t mutex)
 290 {
 291   condition_wait ((condition_t) (condition->backend),
 292                   (mutex_t) (mutex->backend));
 293   return 0;
 294 }
 295
 296 /* Wake up all threads waiting on this condition. */
 297 int
 298 __objc_condition_broadcast (objc_condition_t condition)
 299 {
 300   condition_broadcast ((condition_t) (condition->backend));
 301   return 0;
 302 }
 303
 304 /* Wake up one thread waiting on this condition. */
 305 int
 306 __objc_condition_signal (objc_condition_t condition)
 307 {
 308   condition_signal ((condition_t) (condition->backend));
 309   return 0;
 310 }
 311
 312 /* End of File */