| /* |
| ****************************************************************************** |
| * |
| * Copyright (C) 1997-2009, International Business Machines |
| * Corporation and others. All Rights Reserved. |
| * |
| ****************************************************************************** |
| * |
| * File umutex.c |
| * |
| * Modification History: |
| * |
| * Date Name Description |
| * 04/02/97 aliu Creation. |
| * 04/07/99 srl updated |
| * 05/13/99 stephen Changed to umutex (from cmutex). |
| * 11/22/99 aliu Make non-global mutex autoinitialize [j151] |
| ****************************************************************************** |
| */ |
| |
| #include "unicode/utypes.h" |
| #include "uassert.h" |
| #include "ucln_cmn.h" |
| |
| /* |
| * ICU Mutex wrappers. Wrap operating system mutexes, giving the rest of ICU a |
| * platform independent set of mutex operations. For internal ICU use only. |
| */ |
| |
| #if defined(U_DARWIN) |
| #include <AvailabilityMacros.h> |
| #if (ICU_USE_THREADS == 1) && defined(MAC_OS_X_VERSION_10_4) && defined(MAC_OS_X_VERSION_MIN_REQUIRED) && (MAC_OS_X_VERSION_MIN_REQUIRED >= MAC_OS_X_VERSION_10_4) |
| #if defined(__STRICT_ANSI__) |
| #define UPRV_REMAP_INLINE |
| #define inline |
| #endif |
| #include <libkern/OSAtomic.h> |
| #define USE_MAC_OS_ATOMIC_INCREMENT 1 |
| #if defined(UPRV_REMAP_INLINE) |
| #undef inline |
| #undef UPRV_REMAP_INLINE |
| #endif |
| #endif |
| #endif |
| |
| /* Assume POSIX, and modify as necessary below */ |
| #define POSIX |
| |
| #if defined(U_WINDOWS) |
| #undef POSIX |
| #endif |
| #if defined(macintosh) |
| #undef POSIX |
| #endif |
| #if defined(OS2) |
| #undef POSIX |
| #endif |
| |
| #if defined(POSIX) && (ICU_USE_THREADS==1) |
| # include <pthread.h> /* must be first, so that we get the multithread versions of things. */ |
| |
| #endif /* POSIX && (ICU_USE_THREADS==1) */ |
| |
| #ifdef U_WINDOWS |
| # define WIN32_LEAN_AND_MEAN |
| # define VC_EXTRALEAN |
| # define NOUSER |
| # define NOSERVICE |
| # define NOIME |
| # define NOMCX |
| # include <windows.h> |
| #endif |
| |
| #include "umutex.h" |
| #include "cmemory.h" |
| |
| /* |
| * A note on ICU Mutex Initialization and ICU startup: |
| * |
| * ICU mutexes, as used through the rest of the ICU code, are self-initializing. |
| * To make this work, ICU uses the _ICU GLobal Mutex_ to synchronize the lazy init |
| * of other ICU mutexes. For the global mutex itself, we need some other mechanism |
| * to safely initialize it on first use. This becomes important when two or more |
| * threads are more or less simultaenously the first to use ICU in a process, and |
| * are racing into the mutex initialization code. |
| * |
| * |
| * The solution for the global mutex init is platform dependent. |
| * On POSIX systems, plain C-style initialization can be used on a mutex, with the |
| * macro PTHREAD_MUTEX_INITIALIZER. The mutex is then ready for use, without |
| * first calling pthread_mutex_init(). |
| * |
| * Windows has no equivalent statically initialized mutex or CRITICAL SECION. |
| * InitializeCriticalSection() must be called. If the global mutex does not |
| * appear to be initialized, a thread will create and initialize a new |
| * CRITICAL_SECTION, then use a Windows InterlockedCompareAndExchange to |
| * swap it in as the global mutex while avoid problems with race conditions. |
| */ |
| |
| /* On WIN32 mutexes are reentrant. On POSIX platforms they are not, and a deadlock |
| * will occur if a thread attempts to acquire a mutex it already has locked. |
| * ICU mutexes (in debug builds) include checking code that will cause an assertion |
| * failure if a mutex is reentered. If you are having deadlock problems |
| * on a POSIX machine, debugging may be easier on Windows. |
| */ |
| |
| |
| #if (ICU_USE_THREADS == 0) |
| #define MUTEX_TYPE void * |
| #define PLATFORM_MUTEX_INIT(m) |
| #define PLATFORM_MUTEX_LOCK(m) |
| #define PLATFORM_MUTEX_UNLOCK(m) |
| #define PLATFORM_MUTEX_DESTROY(m) |
| #define PLATFORM_MUTEX_INITIALIZER NULL |
| #define SYNC_COMPARE_AND_SWAP(dest, oldval, newval) \ |
| mutexed_compare_and_swap(dest, newval, oldval) |
| |
| |
| #elif defined(U_WINDOWS) |
| #define MUTEX_TYPE CRITICAL_SECTION |
| #define PLATFORM_MUTEX_INIT(m) InitializeCriticalSection(m) |
| #define PLATFORM_MUTEX_LOCK(m) EnterCriticalSection(m) |
| #define PLATFORM_MUTEX_UNLOCK(m) LeaveCriticalSection(m) |
| #define PLATFORM_MUTEX_DESTROY(m) DeleteCriticalSection(m) |
| #define SYNC_COMPARE_AND_SWAP(dest, oldval, newval) \ |
| InterlockedCompareExchangePointer(dest, newval, oldval) |
| |
| |
| #elif defined(POSIX) |
| #define MUTEX_TYPE pthread_mutex_t |
| #define PLATFORM_MUTEX_INIT(m) pthread_mutex_init(m, NULL) |
| #define PLATFORM_MUTEX_LOCK(m) pthread_mutex_lock(m) |
| #define PLATFORM_MUTEX_UNLOCK(m) pthread_mutex_unlock(m) |
| #define PLATFORM_MUTEX_DESTROY(m) pthread_mutex_destroy(m) |
| #define PLATFORM_MUTEX_INITIALIZER PTHREAD_MUTEX_INITIALIZER |
| #if (U_HAVE_GCC_ATOMICS == 1) |
| #define SYNC_COMPARE_AND_SWAP(dest, oldval, newval) \ |
| __sync_val_compare_and_swap(dest, oldval, newval) |
| #else |
| #define SYNC_COMPARE_AND_SWAP(dest, oldval, newval) \ |
| mutexed_compare_and_swap(dest, newval, oldval) |
| #endif |
| |
| |
| #else |
| /* Unknown platform. Note that user can still set mutex functions at run time. */ |
| #define MUTEX_TYPE void * |
| #define PLATFORM_MUTEX_INIT(m) |
| #define PLATFORM_MUTEX_LOCK(m) |
| #define PLATFORM_MUTEX_UNLOCK(m) |
| #define PLATFORM_MUTEX_DESTROY(m) |
| #define SYNC_COMPARE_AND_SWAP(dest, oldval, newval) \ |
| mutexed_compare_and_swap(dest, newval, oldval) |
| |
| #endif |
| |
| /* Forward declarations */ |
| static void *mutexed_compare_and_swap(void **dest, void *newval, void *oldval); |
| typedef struct ICUMutex ICUMutex; |
| |
| /* |
| * ICUMutex One of these is set up for each UMTX that is used by other ICU code. |
| * The opaque UMTX points to the corresponding ICUMutex struct. |
| * |
| * Because the total number of ICU mutexes is quite small, no effort has |
| * been made to squeeze every byte out of this struct. |
| */ |
| struct ICUMutex { |
| UMTX *owner; /* Points back to the UMTX corrsponding to this */ |
| /* ICUMutex object. */ |
| |
| UBool heapAllocated; /* Set if this ICUMutex is heap allocated, and */ |
| /* will need to be deleted. The global mutex */ |
| /* is static on POSIX platforms; all others */ |
| /* will be heap allocated. */ |
| |
| ICUMutex *next; /* All ICUMutexes are chained into a list so that */ |
| /* they can be found and deleted by u_cleanup(). */ |
| |
| int32_t recursionCount; /* For debugging, detect recursive mutex locks. */ |
| |
| MUTEX_TYPE platformMutex; /* The underlying OS mutex being wrapped. */ |
| |
| UMTX userMutex; /* For use with u_setMutexFunctions operations, */ |
| /* corresponds to platformMutex. */ |
| }; |
| |
| |
| /* The global ICU mutex. |
| * For POSIX platforms, it gets a C style initialization, and is ready to use |
| * at program startup. |
| * For Windows, it will be lazily instantiated on first use. |
| */ |
| |
| #if defined(POSIX) |
| static UMTX globalUMTX; |
| static ICUMutex globalMutex = {&globalUMTX, FALSE, NULL, 0, PLATFORM_MUTEX_INITIALIZER, NULL}; |
| static UMTX globalUMTX = &globalMutex; |
| #else |
| static UMTX globalUMTX = NULL; |
| #endif |
| |
| /* Head of the list of all ICU mutexes. |
| * Linked list is through ICUMutex::next |
| * Modifications to the list are synchronized with the global mutex. |
| * The list is used by u_cleanup(), which needs to dispose of all of the ICU mutexes. |
| * |
| * The statically initialized global mutex on POSIX platforms does not get added to this |
| * mutex list, but that's not a problem - the global mutex gets special handling |
| * during u_cleanup(). |
| */ |
| static ICUMutex *mutexListHead; |
| |
| |
| /* |
| * User mutex implementation functions. If non-null, call back to these rather than |
| * directly using the system (Posix or Windows) APIs. See u_setMutexFunctions(). |
| * (declarations are in uclean.h) |
| */ |
| static UMtxInitFn *pMutexInitFn = NULL; |
| static UMtxFn *pMutexDestroyFn = NULL; |
| static UMtxFn *pMutexLockFn = NULL; |
| static UMtxFn *pMutexUnlockFn = NULL; |
| static const void *gMutexContext = NULL; |
| |
| |
| /* |
| * umtx_lock |
| */ |
| U_CAPI void U_EXPORT2 |
| umtx_lock(UMTX *mutex) |
| { |
| ICUMutex *m; |
| |
| if (mutex == NULL) { |
| mutex = &globalUMTX; |
| } |
| m = (ICUMutex *)*mutex; |
| if (m == NULL) { |
| /* See note on lazy initialization, above. We can get away with it here, with mutexes, |
| * where we couldn't with normal user level data. |
| */ |
| umtx_init(mutex); |
| m = (ICUMutex *)*mutex; |
| } |
| U_ASSERT(m->owner == mutex); |
| |
| if (pMutexLockFn != NULL) { |
| (*pMutexLockFn)(gMutexContext, &m->userMutex); |
| } else { |
| PLATFORM_MUTEX_LOCK(&m->platformMutex); |
| } |
| |
| #if defined(U_DEBUG) |
| m->recursionCount++; /* Recursion causes deadlock on Unixes. */ |
| U_ASSERT(m->recursionCount == 1); /* Recursion detection works on Windows. */ |
| /* Assertion failure on non-Windows indicates a */ |
| /* problem with the mutex implementation itself. */ |
| #endif |
| } |
| |
| |
| |
| /* |
| * umtx_unlock |
| */ |
| U_CAPI void U_EXPORT2 |
| umtx_unlock(UMTX* mutex) |
| { |
| ICUMutex *m; |
| if(mutex == NULL) { |
| mutex = &globalUMTX; |
| } |
| m = (ICUMutex *)*mutex; |
| if (m == NULL) { |
| U_ASSERT(FALSE); /* This mutex is not initialized. */ |
| return; |
| } |
| U_ASSERT(m->owner == mutex); |
| |
| #if defined (U_DEBUG) |
| m->recursionCount--; |
| U_ASSERT(m->recursionCount == 0); /* Detect unlock of an already unlocked mutex */ |
| #endif |
| |
| if (pMutexUnlockFn) { |
| (*pMutexUnlockFn)(gMutexContext, &m->userMutex); |
| } else { |
| PLATFORM_MUTEX_UNLOCK(&m->platformMutex); |
| } |
| } |
| |
| |
| /* umtx_ct Allocate and initialize a new ICUMutex. |
| * If a non-null pointer is supplied, initialize an existing ICU Mutex. |
| */ |
| static ICUMutex *umtx_ct(ICUMutex *m) { |
| if (m == NULL) { |
| m = (ICUMutex *)uprv_malloc(sizeof(ICUMutex)); |
| m->heapAllocated = TRUE; |
| } |
| m->next = NULL; /* List of mutexes is maintained at a higher level. */ |
| m->recursionCount = 0; |
| m->userMutex = NULL; |
| if (pMutexInitFn != NULL) { |
| UErrorCode status = U_ZERO_ERROR; |
| (*pMutexInitFn)(gMutexContext, &m->userMutex, &status); |
| U_ASSERT(U_SUCCESS(status)); |
| } else { |
| PLATFORM_MUTEX_INIT(&m->platformMutex); |
| } |
| return m; |
| } |
| |
| |
| /* umtx_dt Delete a ICUMutex. Destroy the underlying OS Platform mutex. |
| * Does not touch the linked list of ICU Mutexes. |
| */ |
| static void umtx_dt(ICUMutex *m) { |
| if (pMutexDestroyFn != NULL) { |
| (*pMutexDestroyFn)(gMutexContext, &m->userMutex); |
| m->userMutex = NULL; |
| } else { |
| PLATFORM_MUTEX_DESTROY(&m->platformMutex); |
| } |
| |
| if (m->heapAllocated) { |
| uprv_free(m); |
| } |
| } |
| |
| |
| U_CAPI void U_EXPORT2 |
| umtx_init(UMTX *mutex) { |
| ICUMutex *m = NULL; |
| void *originalValue; |
| |
| if (*mutex != NULL) { |
| /* Mutex is already initialized. |
| * Multiple umtx_init()s of a UMTX by other ICU code are explicitly permitted. |
| */ |
| return; |
| } |
| #if defined(POSIX) |
| if (mutex == &globalUMTX) { |
| m = &globalMutex; |
| } |
| #endif |
| |
| m = umtx_ct(m); |
| originalValue = SYNC_COMPARE_AND_SWAP(mutex, NULL, m); |
| if (originalValue != NULL) { |
| umtx_dt(m); |
| return; |
| } |
| |
| m->owner = mutex; |
| |
| /* Hook the new mutex into the list of all ICU mutexes, so that we can find and |
| * delete it for u_cleanup(). |
| */ |
| |
| umtx_lock(NULL); |
| m->next = mutexListHead; |
| mutexListHead = m; |
| umtx_unlock(NULL); |
| return; |
| } |
| |
| |
| /* |
| * umtx_destroy. Un-initialize a mutex, releasing any underlying resources |
| * that it may be holding. Destroying an already destroyed |
| * mutex has no effect. Unlike umtx_init(), this function |
| * is not thread safe; two threads must not concurrently try to |
| * destroy the same mutex. |
| */ |
| U_CAPI void U_EXPORT2 |
| umtx_destroy(UMTX *mutex) { |
| ICUMutex *m; |
| |
| /* No one should be deleting the global ICU mutex. |
| * (u_cleanup() does delete it, but does so explicitly, not by passing NULL) |
| */ |
| U_ASSERT(mutex != NULL); |
| if (mutex == NULL) { |
| return; |
| } |
| |
| m = (ICUMutex *)*mutex; |
| if (m == NULL) { /* Mutex not initialized, or already destroyed. */ |
| return; |
| } |
| |
| U_ASSERT(m->owner == mutex); |
| if (m->owner != mutex) { |
| return; |
| } |
| |
| /* Remove this mutex from the linked list of mutexes. */ |
| umtx_lock(NULL); |
| if (mutexListHead == m) { |
| mutexListHead = m->next; |
| } else { |
| ICUMutex *prev; |
| for (prev = mutexListHead; prev!=NULL && prev->next!=m; prev = prev->next); |
| /* Empty for loop body */ |
| if (prev != NULL) { |
| prev->next = m->next; |
| } |
| } |
| umtx_unlock(NULL); |
| |
| umtx_dt(m); /* Delete the internal ICUMutex */ |
| *mutex = NULL; /* Clear the caller's UMTX */ |
| } |
| |
| |
| |
| U_CAPI void U_EXPORT2 |
| u_setMutexFunctions(const void *context, UMtxInitFn *i, UMtxFn *d, UMtxFn *l, UMtxFn *u, |
| UErrorCode *status) { |
| if (U_FAILURE(*status)) { |
| return; |
| } |
| |
| /* Can not set a mutex function to a NULL value */ |
| if (i==NULL || d==NULL || l==NULL || u==NULL) { |
| *status = U_ILLEGAL_ARGUMENT_ERROR; |
| return; |
| } |
| |
| /* If ICU is not in an initial state, disallow this operation. */ |
| if (cmemory_inUse()) { |
| *status = U_INVALID_STATE_ERROR; |
| return; |
| } |
| |
| /* Kill any existing global mutex. POSIX platforms have a global mutex |
| * even before any other part of ICU is initialized. |
| */ |
| umtx_destroy(&globalUMTX); |
| |
| /* Swap in the mutex function pointers. */ |
| pMutexInitFn = i; |
| pMutexDestroyFn = d; |
| pMutexLockFn = l; |
| pMutexUnlockFn = u; |
| gMutexContext = context; |
| |
| #if defined (POSIX) |
| /* POSIX platforms must have a pre-initialized global mutex |
| * to allow other mutexes to initialize safely. */ |
| umtx_init(&globalUMTX); |
| #endif |
| } |
| |
| |
| /* synchronized compare and swap function, for use when OS or compiler built-in |
| * equivalents aren't available. |
| * |
| * This operation relies on the ICU global mutex for synchronization. |
| * |
| * There are two cases where this function can be entered when the global mutex is not |
| * yet initialized - at the end u_cleanup(), and at the end of u_setMutexFunctions, both |
| * of which re-init the global mutex. But neither function is thread-safe, so the lack of |
| * synchronization at these points doesn't matter. |
| */ |
| static void *mutexed_compare_and_swap(void **dest, void *newval, void *oldval) { |
| void *temp; |
| UBool needUnlock = FALSE; |
| |
| if (globalUMTX != NULL) { |
| umtx_lock(&globalUMTX); |
| needUnlock = TRUE; |
| } |
| |
| temp = *dest; |
| if (temp == oldval) { |
| *dest = newval; |
| } |
| |
| if (needUnlock) { |
| umtx_unlock(&globalUMTX); |
| } |
| return temp; |
| } |
| |
| |
| |
| /*----------------------------------------------------------------- |
| * |
| * Atomic Increment and Decrement |
| * umtx_atomic_inc |
| * umtx_atomic_dec |
| * |
| *----------------------------------------------------------------*/ |
| |
| /* Pointers to user-supplied inc/dec functions. Null if no funcs have been set. */ |
| static UMtxAtomicFn *pIncFn = NULL; |
| static UMtxAtomicFn *pDecFn = NULL; |
| static const void *gIncDecContext = NULL; |
| |
| static UMTX gIncDecMutex = NULL; |
| |
| U_CAPI int32_t U_EXPORT2 |
| umtx_atomic_inc(int32_t *p) { |
| int32_t retVal; |
| if (pIncFn) { |
| retVal = (*pIncFn)(gIncDecContext, p); |
| } else { |
| #if defined (U_WINDOWS) && ICU_USE_THREADS == 1 |
| retVal = InterlockedIncrement((LONG*)p); |
| #elif defined(USE_MAC_OS_ATOMIC_INCREMENT) |
| retVal = OSAtomicIncrement32Barrier(p); |
| #elif (U_HAVE_GCC_ATOMICS == 1) |
| retVal = __sync_add_and_fetch(p, 1); |
| #elif defined (POSIX) && ICU_USE_THREADS == 1 |
| umtx_lock(&gIncDecMutex); |
| retVal = ++(*p); |
| umtx_unlock(&gIncDecMutex); |
| #else |
| /* Unknown Platform, or ICU thread support compiled out. */ |
| retVal = ++(*p); |
| #endif |
| } |
| return retVal; |
| } |
| |
| U_CAPI int32_t U_EXPORT2 |
| umtx_atomic_dec(int32_t *p) { |
| int32_t retVal; |
| if (pDecFn) { |
| retVal = (*pDecFn)(gIncDecContext, p); |
| } else { |
| #if defined (U_WINDOWS) && ICU_USE_THREADS == 1 |
| retVal = InterlockedDecrement((LONG*)p); |
| #elif defined(USE_MAC_OS_ATOMIC_INCREMENT) |
| retVal = OSAtomicDecrement32Barrier(p); |
| #elif (U_HAVE_GCC_ATOMICS == 1) |
| retVal = __sync_sub_and_fetch(p, 1); |
| #elif defined (POSIX) && ICU_USE_THREADS == 1 |
| umtx_lock(&gIncDecMutex); |
| retVal = --(*p); |
| umtx_unlock(&gIncDecMutex); |
| #else |
| /* Unknown Platform, or ICU thread support compiled out. */ |
| retVal = --(*p); |
| #endif |
| } |
| return retVal; |
| } |
| |
| |
| |
| U_CAPI void U_EXPORT2 |
| u_setAtomicIncDecFunctions(const void *context, UMtxAtomicFn *ip, UMtxAtomicFn *dp, |
| UErrorCode *status) { |
| if (U_FAILURE(*status)) { |
| return; |
| } |
| /* Can not set a mutex function to a NULL value */ |
| if (ip==NULL || dp==NULL) { |
| *status = U_ILLEGAL_ARGUMENT_ERROR; |
| return; |
| } |
| /* If ICU is not in an initial state, disallow this operation. */ |
| if (cmemory_inUse()) { |
| *status = U_INVALID_STATE_ERROR; |
| return; |
| } |
| |
| pIncFn = ip; |
| pDecFn = dp; |
| gIncDecContext = context; |
| |
| #if !U_RELEASE |
| { |
| int32_t testInt = 0; |
| U_ASSERT(umtx_atomic_inc(&testInt) == 1); /* Sanity Check. Do the functions work at all? */ |
| U_ASSERT(testInt == 1); |
| U_ASSERT(umtx_atomic_dec(&testInt) == 0); |
| U_ASSERT(testInt == 0); |
| } |
| #endif |
| } |
| |
| |
| |
| /* |
| * Mutex Cleanup Function |
| * |
| * Destroy the global mutex(es), and reset the mutex function callback pointers. |
| */ |
| U_CFUNC UBool umtx_cleanup(void) { |
| ICUMutex *thisMutex = NULL; |
| ICUMutex *nextMutex = NULL; |
| |
| /* Extra, do-nothing function call to suppress compiler warnings on platforms where |
| * mutexed_compare_and_swap is not otherwise used. */ |
| mutexed_compare_and_swap(&globalUMTX, NULL, NULL); |
| |
| /* Delete all of the ICU mutexes. Do the global mutex last because it is used during |
| * the umtx_destroy operation of other mutexes. |
| */ |
| for (thisMutex=mutexListHead; thisMutex!=NULL; thisMutex=nextMutex) { |
| UMTX *umtx = thisMutex->owner; |
| nextMutex = thisMutex->next; |
| U_ASSERT(*umtx = (void *)thisMutex); |
| if (umtx != &globalUMTX) { |
| umtx_destroy(umtx); |
| } |
| } |
| umtx_destroy(&globalUMTX); |
| |
| pMutexInitFn = NULL; |
| pMutexDestroyFn = NULL; |
| pMutexLockFn = NULL; |
| pMutexUnlockFn = NULL; |
| gMutexContext = NULL; |
| pIncFn = NULL; |
| pDecFn = NULL; |
| gIncDecContext = NULL; |
| gIncDecMutex = NULL; |
| |
| #if defined (POSIX) |
| /* POSIX platforms must come out of u_cleanup() with a functioning global mutex |
| * to permit the safe resumption of use of ICU in multi-threaded environments. |
| */ |
| umtx_init(&globalUMTX); |
| #endif |
| return TRUE; |
| } |
| |
| |
