-/*
- * Copyright (c) 2000-2004,2011,2014 Apple Inc. All Rights Reserved.
- *
- * @APPLE_LICENSE_HEADER_START@
- *
- * This file contains Original Code and/or Modifications of Original Code
- * as defined in and that are subject to the Apple Public Source License
- * Version 2.0 (the 'License'). You may not use this file except in
- * compliance with the License. Please obtain a copy of the License at
- * http://www.opensource.apple.com/apsl/ and read it before using this
- * file.
- *
- * The Original Code and all software distributed under the License are
- * distributed on an 'AS IS' basis, WITHOUT WARRANTY OF ANY KIND, EITHER
- * EXPRESS OR IMPLIED, AND APPLE HEREBY DISCLAIMS ALL SUCH WARRANTIES,
- * INCLUDING WITHOUT LIMITATION, ANY WARRANTIES OF MERCHANTABILITY,
- * FITNESS FOR A PARTICULAR PURPOSE, QUIET ENJOYMENT OR NON-INFRINGEMENT.
- * Please see the License for the specific language governing rights and
- * limitations under the License.
- *
- * @APPLE_LICENSE_HEADER_END@
- */
-
-
-//
-// threading - multi-threading support
-//
-// Once upon a time, this file provided a system-independent abstraction layer
-// for various thread models. These times are long gone, and we might as well
-// admit that we're sitting on top of pthreads (plus certain other system facilities).
-//
-#ifndef _H_THREADING
-#define _H_THREADING
-
-#include <security_utilities/utilities.h>
-#include <security_utilities/errors.h>
-#include <security_utilities/debugging.h>
-# include <pthread.h>
-
-#include <security_utilities/threading_internal.h>
-
-
-namespace Security {
-
-
-//
-// Potentially, debug-logging all Mutex activity can really ruin your
-// performance day. We take some measures to reduce the impact, but if
-// you really can't stomach any overhead, define THREAD_NDEBUG to turn
-// (only) thread debug-logging off. NDEBUG will turn this on automatically.
-// On the other hand, throwing out all debug code will change the ABI of
-// Mutexi in incompatible ways. Thus, we still generate the debug-style out-of-line
-// code even with THREAD_NDEBUG, so that debug-style code will work with us.
-// If you want to ditch it completely, #define THREAD_CLEAN_NDEBUG.
-//
-#if defined(NDEBUG) || defined(THREAD_CLEAN_NDEBUG)
-# if !defined(THREAD_NDEBUG)
-# define THREAD_NDEBUG
-# endif
-#endif
-
-
-//
-// An abstraction of a per-thread untyped storage slot of pointer size.
-// Do not use this in ordinary code; this is for implementing other primitives only.
-// Use a PerThreadPointer or ThreadNexus.
-//
-class ThreadStoreSlot {
-public:
- typedef void Destructor(void *);
- ThreadStoreSlot(Destructor *destructor = NULL);
- ~ThreadStoreSlot();
-
- void *get() const { return pthread_getspecific(mKey); }
- operator void * () const { return get(); }
- void operator = (void *value) const
- {
- if (int err = pthread_setspecific(mKey, value))
- UnixError::throwMe(err);
- }
-
-private:
- pthread_key_t mKey;
-};
-
-
-//
-// Per-thread pointers are implemented using the pthread TLS (thread local storage)
-// facility.
-// Let's be clear on what gets destroyed when, here. Following the pthread lead,
-// when a thread dies its PerThreadPointer object(s) are properly destroyed.
-// However, if a PerThreadPointer itself is destroyed, NOTHING HAPPENS. Yes, there are
-// reasons for this. This is not (on its face) a bug, so don't yell. But be aware...
-//
-template <class T>
-class PerThreadPointer : public ThreadStoreSlot {
-public:
- PerThreadPointer(bool cleanup = true) : ThreadStoreSlot(cleanup ? destructor : NULL) { }
- operator bool() const { return get() != NULL; }
- operator T * () const { return reinterpret_cast<T *>(get()); }
- T *operator -> () const { return static_cast<T *>(*this); }
- T &operator * () const { return *static_cast<T *>(get()); }
- void operator = (T *t) { ThreadStoreSlot::operator = (t); }
-
-private:
- static void destructor(void *element)
- { delete reinterpret_cast<T *>(element); }
-};
-
-
-//
-// Pthread Synchronization primitives.
-// These have a common header, strictly for our convenience.
-//
-class LockingPrimitive {
-protected:
- LockingPrimitive() { }
-
- void check(int err) { if (err) UnixError::throwMe(err); }
-};
-
-
-//
-// Mutexi
-//
-class Mutex : public LockingPrimitive {
- NOCOPY(Mutex)
- friend class Condition;
-
-public:
- enum Type {
- normal,
- recursive
- };
-
- Mutex(); // normal
- Mutex(Type type); // recursive
- ~Mutex(); // destroy (must be unlocked)
- void lock(); // lock and wait
- bool tryLock(); // instantaneous lock (return false if busy)
- void unlock(); // unlock (must be locked)
-
-private:
- pthread_mutex_t me;
-};
-
-
-class RecursiveMutex : public Mutex
-{
-public:
- RecursiveMutex() : Mutex(recursive) {}
- ~RecursiveMutex() {}
-};
-
-//
-// Condition variables
-//
-class Condition : public LockingPrimitive {
- NOCOPY(Condition)
-
-public:
- Condition(Mutex &mutex); // create with specific Mutex
- ~Condition();
- void wait(); // wait for signal
- void signal(); // signal one
- void broadcast(); // signal all
-
- Mutex &mutex; // associated Mutex
-
-private:
- pthread_cond_t me;
-};
-
-
-//
-// A CountingMutex adds a counter to a Mutex.
-// NOTE: This is not officially a semaphore - it's an automatically managed
-// counter married to a Mutex.
-//
-class CountingMutex : public Mutex {
-public:
- CountingMutex() : mCount(0) { }
- ~CountingMutex() { assert(mCount == 0); }
-
- void enter(); // lock, add one, unlock
- bool tryEnter(); // enter or return false
- void exit(); // lock, subtract one, unlock
-
- // these methods do not lock - use only while you hold the lock
- unsigned int count() const { return mCount; }
- bool isIdle() const { return mCount == 0; }
-
- // convert Mutex lock to CountingMutex enter/exit. Expert use only
- void finishEnter(); // all but the initial lock
- void finishExit(); // all but the initial lock
-
-private:
- unsigned int mCount; // counter level
-};
-
-
-//
-// A guaranteed-unlocker stack-based class.
-// By default, this will use lock/unlock methods, but you can provide your own
-// alternates (to, e.g., use enter/exit, or some more specialized pair of operations).
-//
-// NOTE: StLock itself is not thread-safe. It is intended for use (usually on the stack)
-// by a single thread.
-//
-template <class Lock,
- void (Lock::*_lock)() = &Lock::lock,
- void (Lock::*_unlock)() = &Lock::unlock>
-class StLock {
-public:
- StLock(Lock &lck) : me(lck) { (me.*_lock)(); mActive = true; }
- StLock(Lock &lck, bool option) : me(lck), mActive(option) { }
- ~StLock() { if (mActive) (me.*_unlock)(); }
-
- bool isActive() const { return mActive; }
- void lock() { if(!mActive) { (me.*_lock)(); mActive = true; }}
- void unlock() { if(mActive) { (me.*_unlock)(); mActive = false; }}
- void release() { assert(mActive); mActive = false; }
-
- operator const Lock &() const { return me; }
-
-protected:
- Lock &me;
- bool mActive;
-};
-
-template <class TakeLock, class ReleaseLock,
- void (TakeLock::*_lock)() = &TakeLock::lock,
- void (TakeLock::*_unlock)() = &TakeLock::unlock,
- void (ReleaseLock::*_rlock)() = &ReleaseLock::lock,
- void (ReleaseLock::*_runlock)() = &ReleaseLock::unlock>
-class StSyncLock {
-public:
- StSyncLock(TakeLock &tlck, ReleaseLock &rlck) : taken(tlck), released(rlck) {
- (released.*_unlock)();
- (taken.*_lock)();
- mActive = true;
- }
- StSyncLock(TakeLock &tlck, ReleaseLock &rlck, bool option) : taken(tlck), released(rlck), mActive(option) { }
- ~StSyncLock() { if (mActive) { (taken.*_unlock)(); (released.*_rlock)(); }}
-
- bool isActive() const { return mActive; }
- void lock() { if(!mActive) { (released.*_runlock)(); (taken.*_lock)(); mActive = true; }}
- void unlock() { if(mActive) { (taken.*_unlock)(); (released.*_rlock)(); mActive = false; }}
- void release() { assert(mActive); mActive = false; }
-
-protected:
- TakeLock &taken;
- ReleaseLock &released;
- bool mActive;
-};
-
-
-//
-// Atomic increment/decrement operations.
-// The default implementation uses a Mutex. However, many architectures can do
-// much better than that.
-// Be very clear on the nature of AtomicCounter. It implies no memory barriers of
-// any kind. This means that (1) you cannot protect any other memory region with it
-// (use a Mutex for that), and (2) it may not enforce cross-processor ordering, which
-// means that you have no guarantee that you'll see modifications by other processors
-// made earlier (unless another mechanism provides the memory barrier).
-// On the other hand, if your compiler has brains, this is blindingly fast...
-//
-template <class Integer = uint32_t>
-class StaticAtomicCounter {
-protected:
- Integer mValue;
-
-public:
- operator Integer() const { return mValue; }
-
- // infix versions (primary)
- Integer operator ++ () { return Atomic<Integer>::increment(mValue); }
- Integer operator -- () { return Atomic<Integer>::decrement(mValue); }
-
- // postfix versions
- Integer operator ++ (int) { return Atomic<Integer>::increment(mValue) - 1; }
- Integer operator -- (int) { return Atomic<Integer>::decrement(mValue) + 1; }
-
- // generic offset
- Integer operator += (int delta) { return Atomic<Integer>::add(delta, mValue); }
-};
-
-
-template <class Integer = int>
-class AtomicCounter : public StaticAtomicCounter<Integer> {
-public:
- AtomicCounter(Integer init = 0) { StaticAtomicCounter<Integer>::mValue = init; }
-};
-
-
-//
-// A class implementing a separate thread of execution.
-// Do not expect many high-level semantics to be portable. If you can,
-// restrict yourself to expect parallel execution and little else.
-//
-class Thread {
- NOCOPY(Thread)
-public:
- class Identity {
- friend class Thread;
-
- Identity(pthread_t id) : mIdent(id) { }
- public:
- Identity() { }
-
- static Identity current() { return pthread_self(); }
-
- bool operator == (const Identity &other) const
- { return pthread_equal(mIdent, other.mIdent); }
-
- bool operator != (const Identity &other) const
- { return !(*this == other); }
-
- private:
- pthread_t mIdent;
- };
-
-public:
- Thread() { } // constructor
- virtual ~Thread(); // virtual destructor
- void run(); // begin running the thread
-
-public:
- static void yield(); // unstructured short-term processor yield
-
-protected:
- virtual void action() = 0; // the action to be performed
-
-private:
- Identity self; // my own identity (instance constant)
-
- static void *runner(void *); // argument to pthread_create
-};
-
-
-//
-// A "just run this function in a thread" variant of Thread
-//
-class ThreadRunner : public Thread {
- typedef void Action();
-public:
- ThreadRunner(Action *todo);
-
-private:
- void action();
- Action *mAction;
-};
-
-
-} // end namespace Security
-
-#endif //_H_THREADING
projects / apple / security.git / blobdiff