OSX/libsecurity_utilities/lib/threading.cpp

   1 /*
   2  * Copyright (c) 2000-2004,2011-2012,2014 Apple Inc. All Rights Reserved.
   3  *
   4  * @APPLE_LICENSE_HEADER_START@
   5  *
   6  * This file contains Original Code and/or Modifications of Original Code
   7  * as defined in and that are subject to the Apple Public Source License
   8  * Version 2.0 (the 'License'). You may not use this file except in
   9  * compliance with the License. Please obtain a copy of the License at
  10  * http://www.opensource.apple.com/apsl/ and read it before using this
  11  * file.
  12  *
  13  * The Original Code and all software distributed under the License are
  14  * distributed on an 'AS IS' basis, WITHOUT WARRANTY OF ANY KIND, EITHER
  15  * EXPRESS OR IMPLIED, AND APPLE HEREBY DISCLAIMS ALL SUCH WARRANTIES,
  16  * INCLUDING WITHOUT LIMITATION, ANY WARRANTIES OF MERCHANTABILITY,
  17  * FITNESS FOR A PARTICULAR PURPOSE, QUIET ENJOYMENT OR NON-INFRINGEMENT.
  18  * Please see the License for the specific language governing rights and
  19  * limitations under the License.
  20  *
  21  * @APPLE_LICENSE_HEADER_END@
  22  */
  23
  24
  25 //
  26 // threading - generic thread support
  27 //
  28 #include <security_utilities/threading.h>
  29 #include <security_utilities/globalizer.h>
  30 #include <security_utilities/memutils.h>
  31 #include <utilities/debugging.h>
  32
  33 #include <unistd.h>     // WWDC 2007 thread-crash workaround
  34 #include <syslog.h>     // WWDC 2007 thread-crash workaround
  35
  36 //
  37 // Thread-local storage primitive
  38 //
  39 ThreadStoreSlot::ThreadStoreSlot(Destructor *destructor)
  40 {
  41     if (int err = pthread_key_create(&mKey, destructor))
  42         UnixError::throwMe(err);
  43 }
  44
  45 ThreadStoreSlot::~ThreadStoreSlot()
  46 {
  47     //@@@ if we wanted to dispose of pending task objects, we'd have
  48     //@@@ to keep a set of them and delete them explicitly here
  49     pthread_key_delete(mKey);
  50 }
  51
  52
  53 //
  54 // Mutex implementation
  55 //
  56 struct MutexAttributes {
  57         pthread_mutexattr_t recursive;
  58         pthread_mutexattr_t checking;
  59
  60         MutexAttributes()
  61         {
  62                 pthread_mutexattr_init(&recursive);
  63                 pthread_mutexattr_settype(&recursive, PTHREAD_MUTEX_RECURSIVE);
  64 #if !defined(NDEBUG)
  65                 pthread_mutexattr_init(&checking);
  66                 pthread_mutexattr_settype(&checking, PTHREAD_MUTEX_ERRORCHECK);
  67 #endif //NDEBUG
  68         }
  69 };
  70
  71 static ModuleNexus<MutexAttributes> mutexAttrs;
  72
  73
  74 Mutex::Mutex()
  75 {
  76         check(pthread_mutex_init(&me, NULL));
  77 }
  78
  79 Mutex::Mutex(Type type)
  80 {
  81         switch (type) {
  82         case normal:
  83                 check(pthread_mutex_init(&me, IFELSEDEBUG(&mutexAttrs().checking, NULL)));
  84                 break;
  85         case recursive:         // requested recursive (is also checking, always)
  86                 check(pthread_mutex_init(&me, &mutexAttrs().recursive));
  87                 break;
  88         };
  89 }
  90
  91
  92 Mutex::~Mutex()
  93 {
  94     int result = pthread_mutex_destroy(&me);
  95     if(result) {
  96         secerror("Probable bug: error destroying Mutex: %d", result);
  97     }
  98         check(result);
  99 }
 100
 101
 102 void Mutex::lock()
 103 {
 104         check(pthread_mutex_lock(&me));
 105 }
 106
 107
 108 bool Mutex::tryLock()
 109 {
 110         if (int err = pthread_mutex_trylock(&me)) {
 111                 if (err != EBUSY)
 112                         UnixError::throwMe(err);
 113                 return false;
 114         }
 115
 116         return true;
 117 }
 118
 119
 120 void Mutex::unlock()
 121 {
 122     int result = pthread_mutex_unlock(&me);
 123         check(result);
 124 }
 125
 126
 127 //
 128 // Condition variables
 129 //
 130 Condition::Condition(Mutex &lock) : mutex(lock)
 131 {
 132     check(pthread_cond_init(&me, NULL));
 133 }
 134
 135 Condition::~Condition()
 136 {
 137         check(pthread_cond_destroy(&me));
 138 }
 139
 140 void Condition::wait()
 141 {
 142     check(pthread_cond_wait(&me, &mutex.me));
 143 }
 144
 145 void Condition::signal()
 146 {
 147     check(pthread_cond_signal(&me));
 148 }
 149
 150 void Condition::broadcast()
 151 {
 152     check(pthread_cond_broadcast(&me));
 153 }
 154
 155
 156 //
 157 // CountingMutex implementation.
 158 //
 159 void CountingMutex::enter()
 160 {
 161     lock();
 162     mCount++;
 163     unlock();
 164 }
 165
 166 bool CountingMutex::tryEnter()
 167 {
 168     if (!tryLock())
 169         return false;
 170     mCount++;
 171     unlock();
 172     return true;
 173 }
 174
 175 void CountingMutex::exit()
 176 {
 177     lock();
 178     assert(mCount > 0);
 179     mCount--;
 180     unlock();
 181 }
 182
 183 void CountingMutex::finishEnter()
 184 {
 185     mCount++;
 186     unlock();
 187 }
 188
 189 void CountingMutex::finishExit()
 190 {
 191     assert(mCount > 0);
 192     mCount--;
 193     unlock();
 194 }
 195
 196 //
 197 // ReadWriteLock implementation
 198 //
 199 ReadWriteLock::ReadWriteLock() {
 200     check(pthread_rwlock_init(&mLock, NULL));
 201 }
 202
 203 bool ReadWriteLock::lock() {
 204     check(pthread_rwlock_rdlock(&mLock));
 205     return true;
 206 }
 207
 208 bool ReadWriteLock::tryLock() {
 209     return (pthread_rwlock_tryrdlock(&mLock) == 0);
 210 }
 211
 212 bool ReadWriteLock::writeLock() {
 213     check(pthread_rwlock_wrlock(&mLock));
 214     return true;
 215 }
 216
 217 bool ReadWriteLock::tryWriteLock() {
 218     return (pthread_rwlock_trywrlock(&mLock) == 0);
 219 }
 220
 221 void ReadWriteLock::unlock() {
 222     check(pthread_rwlock_unlock(&mLock));
 223 }
 224
 225 //
 226 // StReadWriteLock implementation
 227 //
 228 bool StReadWriteLock::lock() {
 229     switch(mType) {
 230         case Read:     mIsLocked = mRWLock.lock(); break;
 231         case TryRead:  mIsLocked = mRWLock.tryLock(); break;
 232         case Write:    mIsLocked = mRWLock.writeLock(); break;
 233         case TryWrite: mIsLocked = mRWLock.tryWriteLock(); break;
 234     }
 235     return mIsLocked;
 236 }
 237
 238 void StReadWriteLock::unlock() {
 239     mRWLock.unlock();
 240     mIsLocked = false;
 241 }
 242
 243 bool StReadWriteLock::isLocked() {
 244     return mIsLocked;
 245 }
 246
 247
 248
 249 //
 250 // Threads implementation
 251 //
 252 Thread::~Thread()
 253 {
 254 }
 255
 256 void Thread::run()
 257 {
 258     pthread_attr_t ptattrs;
 259     int err, ntries = 10;       // 10 is arbitrary
 260
 261     if ((err = pthread_attr_init(&ptattrs)) ||
 262         (err = pthread_attr_setdetachstate(&ptattrs, PTHREAD_CREATE_DETACHED)))
 263     {
 264         syslog(LOG_ERR, "error %d setting thread detach state", err);
 265     }
 266     while ((err = pthread_create(&self.mIdent, &ptattrs, runner, this) &&
 267            --ntries))
 268     {
 269         syslog(LOG_ERR, "pthread_create() error %d", err);
 270         usleep(50000);          // 50 ms is arbitrary
 271     }
 272     if (err)
 273     {
 274         syslog(LOG_ERR, "too many failed pthread_create() attempts");
 275     }
 276     else
 277         secinfo("thread", "%p created", self.mIdent);
 278 }
 279
 280 void *Thread::runner(void *arg)
 281 {
 282     try // the top level of any running thread of execution must have a try/catch around it,
 283         // otherwise it will crash if something underneath throws.
 284     {
 285         Thread *me = static_cast<Thread *>(arg);
 286         secinfo("thread", "%p starting", me->self.mIdent);
 287         me->action();
 288         secinfo("thread", "%p terminating", me->self.mIdent);
 289         delete me;
 290         return NULL;
 291     }
 292     catch (...)
 293     {
 294         return NULL;
 295     }
 296 }
 297
 298 void Thread::yield()
 299 {
 300         ::sched_yield();
 301 }
 302
 303
 304 //
 305 // ThreadRunner implementation
 306 //
 307 ThreadRunner::ThreadRunner(Action *todo)
 308 {
 309     mAction = todo;
 310     run();
 311 }
 312
 313 void ThreadRunner::action()
 314 {
 315     mAction();
 316 }