/*
* Mark this event as disabled. Any future attempts to add a hook for this event
* will result in an error.
*
* This function should not be called directly. It should be called through the hook interface
*
* Returns 0 on success, or non-zero if the event is already hooked or reserved
*/
static intptr_t
J9HookDisable(struct J9HookInterface **hookInterface, uintptr_t taggedEventNum)
{
J9CommonHookInterface *commonInterface = (J9CommonHookInterface *)hookInterface;
uintptr_t eventNum = taggedEventNum & J9HOOK_EVENT_NUM_MASK;
/* try to answer without using the lock, first */
if (HOOK_FLAGS(commonInterface, eventNum) & J9HOOK_FLAG_RESERVED) {
return -1;
} else if (HOOK_FLAGS(commonInterface, eventNum) & J9HOOK_FLAG_DISABLED) {
return 0;
} else {
intptr_t rc = 0;
omrthread_monitor_enter(commonInterface->lock);
if (HOOK_FLAGS(commonInterface, eventNum) & (J9HOOK_FLAG_RESERVED | J9HOOK_FLAG_HOOKED)) {
rc = -1;
} else {
HOOK_FLAGS(commonInterface, eventNum) |= J9HOOK_FLAG_DISABLED;
}
omrthread_monitor_exit(commonInterface->lock);
return rc;
}
}
/*
* Inform all registered listeners that the specified event has occurred. Details about the
* event should be available through eventData.
*
* If the J9HOOK_TAG_ONCE bit is set in the taggedEventNum, then the event is disabled
* before the listeners are informed. Any attempts to add listeners to a TAG_ONCE event
* once it has been reported will fail.
*
* This function should not be called directly. It should be called through the hook interface
*
*/
static void
J9HookDispatch(struct J9HookInterface **hookInterface, uintptr_t taggedEventNum, void *eventData)
{
uintptr_t eventNum = taggedEventNum & J9HOOK_EVENT_NUM_MASK;
J9CommonHookInterface *commonInterface = (J9CommonHookInterface *)hookInterface;
J9HookRecord *record = HOOK_RECORD(commonInterface, eventNum);
if (taggedEventNum & J9HOOK_TAG_ONCE) {
uint8_t oldFlags;
omrthread_monitor_enter(commonInterface->lock);
oldFlags = HOOK_FLAGS(commonInterface, eventNum);
/* clear the HOOKED and RESERVED flags and set the DISABLED flag */
HOOK_FLAGS(commonInterface, eventNum) = (oldFlags | J9HOOK_FLAG_DISABLED) & ~(J9HOOK_FLAG_RESERVED | J9HOOK_FLAG_HOOKED);
omrthread_monitor_exit(commonInterface->lock);
if (oldFlags & J9HOOK_FLAG_DISABLED) {
/* already reported */
return;
}
}
while (record) {
J9HookFunction function;
void *userData;
uintptr_t id;
/* ensure that the id is read before any other fields */
id = record->id;
if (HOOK_IS_VALID_ID(id)) {
VM_AtomicSupport::readBarrier();
function = record->function;
userData = record->userData;
/* now read the id again to make sure that nothing has changed */
VM_AtomicSupport::readBarrier();
if (record->id == id) {
function(hookInterface, eventNum, eventData, userData);
} else {
/* this record has been updated while we were reading it. Skip it. */
}
}
record = record->next;
}
}
/*
* Remove the specified function from the listeners for eventNum.
* If userData is NULL, all functions matching function are removed.
* If userData is non-NULL, only functions with matching userData are removed.
*
* This function should not be called directly. It should be called through the hook interface
*/
static void
J9HookUnregister(struct J9HookInterface **hookInterface, uintptr_t taggedEventNum, J9HookFunction function, void *userData)
{
J9CommonHookInterface *commonInterface = (J9CommonHookInterface *)hookInterface;
J9HookRecord *record;
J9HookRegistrationEvent eventStruct;
uintptr_t hooksRemaining = 0;
uintptr_t hooksRemoved = 0;
uintptr_t eventNum = taggedEventNum & J9HOOK_EVENT_NUM_MASK;
eventStruct.eventNum = eventNum;
eventStruct.function = function;
eventStruct.isRegistration = 0;
eventStruct.userData = NULL;
eventStruct.agentID = J9HOOK_AGENTID_DEFAULT;
omrthread_monitor_enter(commonInterface->lock);
record = HOOK_RECORD(commonInterface, eventNum);
while (record) {
if (record->function == function) {
if ((userData == NULL) || (record->userData == userData)) {
if (taggedEventNum & J9HOOK_TAG_COUNTED) {
if (--(record->count) != 0) {
omrthread_monitor_exit(commonInterface->lock);
return;
}
}
if (userData != NULL) {
/* copy data from the event record so that we can report it once we've released the mutex */
eventStruct.userData = record->userData;
eventStruct.agentID = record->agentID;
}
/* mark the record as invalid so that it can be recycled */
record->id = HOOK_INVALID_ID(record->id);
hooksRemoved++;
}
}
if (HOOK_IS_VALID_ID(record->id)) {
hooksRemaining++;
}
record = record->next;
}
if (hooksRemaining == 0) {
HOOK_FLAGS(commonInterface, eventNum) &= ~J9HOOK_FLAG_HOOKED;
}
omrthread_monitor_exit(commonInterface->lock);
if (hooksRemoved != 0) {
/* report the unregistration event */
(*hookInterface)->J9HookDispatch(hookInterface, J9HOOK_REGISTRATION_EVENT, &eventStruct);
}
}
/**
* Determine if the specified event has been disabled. This function does not modify the
* hook interface in any way. Note that there's no atomic protection of any kind -- just
* because the event wasn't disabled when you called this function doesn't mean that it
* won't be by the time you try to register for it.
*
* @return 0 (false) if the event is disabled, non-zero (true) if the event is not disabled.
*/
static intptr_t
J9HookIsEnabled(struct J9HookInterface **hookInterface, uintptr_t taggedEventNum)
{
J9CommonHookInterface *commonInterface = (J9CommonHookInterface *)hookInterface;
uintptr_t eventNum = taggedEventNum & J9HOOK_EVENT_NUM_MASK;
if (HOOK_FLAGS(commonInterface, eventNum) & J9HOOK_FLAG_DISABLED) {
return 0;
}
#if 0
/* at some point, we may wish to distinguish between 'not disabled' and reserved. */
if (HOOK_FLAGS(commonInterface, eventNum) & J9HOOK_FLAG_RESERVED) {
return 2;
}
#endif
return 1;
}
/*
* Use J9HookReserve to indicate your intention to hook an event in the future.
* Certain events must be reserved before the providing module initializes completely,
* or it may make decisions which make it impossible to add the hooks later.
* Once the point of no-return is reached, the providing module will disable the
* event if it has not been registered or reserved.
*
* This function should not be called directly. It should be called through the hook interface
*
* returns 0 on success
* non-zero if the event has been disabled
*/
static intptr_t
J9HookReserve(struct J9HookInterface **hookInterface, uintptr_t taggedEventNum)
{
J9CommonHookInterface *commonInterface = (J9CommonHookInterface *)hookInterface;
intptr_t rc = 0;
uintptr_t eventNum = taggedEventNum & J9HOOK_EVENT_NUM_MASK;
omrthread_monitor_enter(commonInterface->lock);
if (HOOK_FLAGS(commonInterface, eventNum) & J9HOOK_FLAG_DISABLED) {
rc = -1;
} else {
HOOK_FLAGS(commonInterface, eventNum) |= J9HOOK_FLAG_RESERVED;
}
omrthread_monitor_exit(commonInterface->lock);
return rc;
}
static intptr_t
J9HookRegisterWithCallSitePrivate(struct J9HookInterface **hookInterface, uintptr_t taggedEventNum, J9HookFunction function, const char *callsite, void *userData, uintptr_t agentID)
{
J9CommonHookInterface *commonInterface = (J9CommonHookInterface *)hookInterface;
J9HookRegistrationEvent eventStruct;
intptr_t rc = 0;
uintptr_t eventNum = taggedEventNum & J9HOOK_EVENT_NUM_MASK;
omrthread_monitor_enter(commonInterface->lock);
if (HOOK_FLAGS(commonInterface, eventNum) & J9HOOK_FLAG_DISABLED) {
rc = -1;
} else {
J9HookRecord *insertionPoint = NULL;
J9HookRecord *emptyRecord = NULL;
J9HookRecord *record = HOOK_RECORD(commonInterface, eventNum);
/* at the end of the loop, insertionPoint will point to the last record which should be triggered before the one we're adding */
while (record) {
if ((taggedEventNum & J9HOOK_TAG_REVERSE_ORDER) ? record->agentID >= agentID : record->agentID <= agentID) {
insertionPoint = record;
}
if (!HOOK_IS_VALID_ID(record->id)) {
if ((taggedEventNum & J9HOOK_TAG_REVERSE_ORDER) ? record->agentID >= agentID : record->agentID <= agentID) {
emptyRecord = record;
}
} else if ((record->function == function) && (record->userData == userData)) {
/* this listener is already registered */
++(record->count);
omrthread_monitor_exit(commonInterface->lock);
return 0;
}
record = record->next;
}
/*
* Re-use the empty record if it is in a legitimate position for the requested agent.
* (It is a legitimate position if all records before this position have the same or lower agent IDs (tested previously)
* and all records after this position have the same or higher IDs)
*/
if ((emptyRecord != NULL)
&& ((emptyRecord->next == NULL)
|| ((taggedEventNum & J9HOOK_TAG_REVERSE_ORDER) ?
(emptyRecord->next->agentID <= agentID) :
(emptyRecord->next->agentID >= agentID)))
) {
emptyRecord->function = function;
emptyRecord->callsite = callsite;
emptyRecord->userData = userData;
emptyRecord->count = 1;
emptyRecord->agentID = agentID;
VM_AtomicSupport::writeBarrier();
emptyRecord->id = HOOK_VALID_ID(emptyRecord->id);
HOOK_FLAGS(commonInterface, eventNum) |= J9HOOK_FLAG_HOOKED | J9HOOK_FLAG_RESERVED;
} else {
record = (J9HookRecord *)pool_newElement(commonInterface->pool);
if (record == NULL) {
rc = -1;
} else {
if (insertionPoint == NULL) {
record->next = HOOK_RECORD(commonInterface, eventNum);
} else {
record->next = insertionPoint->next;
}
record->function = function;
record->callsite = callsite;
record->userData = userData;
record->count = 1;
record->id = HOOK_INITIAL_ID;
record->agentID = agentID;
VM_AtomicSupport::writeBarrier();
if (insertionPoint == NULL) {
HOOK_RECORD(commonInterface, eventNum) = record;
} else {
insertionPoint->next = record;
}
HOOK_FLAGS(commonInterface, eventNum) |= J9HOOK_FLAG_HOOKED | J9HOOK_FLAG_RESERVED;
}
}
}
omrthread_monitor_exit(commonInterface->lock);
/* report the registration event */
eventStruct.eventNum = eventNum;
eventStruct.function = function;
eventStruct.userData = userData;
eventStruct.isRegistration = 1;
eventStruct.agentID = agentID;
(*hookInterface)->J9HookDispatch(hookInterface, J9HOOK_REGISTRATION_EVENT, &eventStruct);
return rc;
}
/*
* Inform all registered listeners that the specified event has occurred. Details about the
* event should be available through eventData.
*
* If the J9HOOK_TAG_ONCE bit is set in the taggedEventNum, then the event is disabled
* before the listeners are informed. Any attempts to add listeners to a TAG_ONCE event
* once it has been reported will fail.
*
* This function should not be called directly. It should be called through the hook interface
*
*/
static void
J9HookDispatch(struct J9HookInterface **hookInterface, uintptr_t taggedEventNum, void *eventData)
{
uintptr_t eventNum = taggedEventNum & J9HOOK_EVENT_NUM_MASK;
J9CommonHookInterface *commonInterface = (J9CommonHookInterface *)hookInterface;
J9HookRecord *record = HOOK_RECORD(commonInterface, eventNum);
OMREventInfo4Dump *eventDump = J9HOOK_DUMPINFO(commonInterface, eventNum);
uintptr_t samplingInterval = (taggedEventNum & J9HOOK_TAG_SAMPLING_MASK) >> 16;
bool sampling = false;
if (taggedEventNum & J9HOOK_TAG_ONCE) {
uint8_t oldFlags;
omrthread_monitor_enter(commonInterface->lock);
oldFlags = HOOK_FLAGS(commonInterface, eventNum);
/* clear the HOOKED and RESERVED flags and set the DISABLED flag */
HOOK_FLAGS(commonInterface, eventNum) = (oldFlags | J9HOOK_FLAG_DISABLED) & ~(J9HOOK_FLAG_RESERVED | J9HOOK_FLAG_HOOKED);
omrthread_monitor_exit(commonInterface->lock);
if (oldFlags & J9HOOK_FLAG_DISABLED) {
/* already reported */
return;
}
}
while (record) {
J9HookFunction function;
void *userData;
uintptr_t id;
/* ensure that the id is read before any other fields */
id = record->id;
if (HOOK_IS_VALID_ID(id)) {
VM_AtomicSupport::readBarrier();
function = record->function;
userData = record->userData;
/* now read the id again to make sure that nothing has changed */
VM_AtomicSupport::readBarrier();
if (record->id == id) {
uint64_t startTime = 0;
uintptr_t count = 0;
if (NULL != eventDump) {
count = VM_AtomicSupport::add((volatile uintptr_t *)&eventDump->count, 1);
sampling = (1 >= samplingInterval) || ((100 >= samplingInterval) && (0 == (count % samplingInterval)));
} else {
sampling = false;
}
OMRPORT_ACCESS_FROM_OMRPORT(commonInterface->portLib);
if (sampling) {
startTime = omrtime_current_time_millis();
}
function(hookInterface, eventNum, eventData, userData);
if (sampling) {
uint64_t timeDelta = omrtime_current_time_millis() - startTime;
eventDump->lastHook.startTime = startTime;
eventDump->lastHook.callsite = record->callsite;
eventDump->lastHook.func_ptr = (void *)record->function;
eventDump->lastHook.duration = timeDelta;
if ((eventDump->longestHook.duration < timeDelta) ||
(0 == eventDump->longestHook.startTime)) {
eventDump->longestHook.startTime = startTime;
eventDump->longestHook.callsite = record->callsite;
eventDump->longestHook.func_ptr = (void *)record->function;
eventDump->longestHook.duration = timeDelta;
}
if (commonInterface->threshold4Trace <= timeDelta) {
const char *callsite = "UNKNOWN";
char buffer[32];
if (NULL != record->callsite) {
callsite = record->callsite;
} else {
/* if the callsite info can not be retrieved, use callback function pointer instead */
omrstr_printf(buffer, sizeof(buffer), "0x%p", record->function);
callsite = buffer;
}
Trc_Hook_Dispatch_Exceed_Threshold_Event(callsite, timeDelta);
}
}
} else {
/* this record has been updated while we were reading it. Skip it. */
}
}
record = record->next;
}
}
