MessagingArea *
MessagingArea::Create(sem_id lockSem, sem_id counterSem)
{
// allocate the object on the heap
MessagingArea *area = new(nothrow) MessagingArea;
if (!area)
return NULL;
// create the area
area->fID = create_area("messaging", (void**)&area->fHeader,
B_ANY_KERNEL_ADDRESS, kMessagingAreaSize, B_FULL_LOCK,
B_KERNEL_READ_AREA | B_KERNEL_WRITE_AREA | B_USER_CLONEABLE_AREA);
if (area->fID < 0) {
delete area;
return NULL;
}
// finish the initialization of the object
area->fSize = kMessagingAreaSize;
area->fLockSem = lockSem;
area->fCounterSem = counterSem;
area->fNextArea = NULL;
area->InitHeader();
return area;
}
status_t
MessagingService::UnregisterService()
{
// check, if the team calling this function is indeed the server team
thread_info threadInfo;
status_t error = get_thread_info(find_thread(NULL), &threadInfo);
if (error != B_OK)
return error;
if (threadInfo.team != fServerTeam)
return B_BAD_VALUE;
// delete all areas
while (fFirstArea) {
MessagingArea *area = fFirstArea;
fFirstArea = area->NextArea();
delete area;
}
fLastArea = NULL;
// unset the other members
fLockSem = -1;
fCounterSem = -1;
fServerTeam = -1;
return B_OK;
}
status_t
MessagingService::SendMessage(const void *message, int32 messageSize,
const messaging_target *targets, int32 targetCount)
{
PRINT(("MessagingService::SendMessage(%p, %ld, %p, %ld)\n", message,
messageSize, targets, targetCount));
if (!message || messageSize <= 0 || !targets || targetCount <= 0)
return B_BAD_VALUE;
int32 dataSize = sizeof(messaging_command_send_message)
+ targetCount * sizeof(messaging_target) + messageSize;
// allocate space for the command
MessagingArea *area;
void *data;
bool wasEmpty;
status_t error = _AllocateCommand(MESSAGING_COMMAND_SEND_MESSAGE, dataSize,
area, data, wasEmpty);
if (error != B_OK) {
PRINT(("MessagingService::SendMessage(): Failed to allocate space for "
"send message command.\n"));
return error;
}
PRINT((" Allocated space for send message command: area: %p, data: %p, "
"wasEmpty: %d\n", area, data, wasEmpty));
// prepare the command
messaging_command_send_message *command
= (messaging_command_send_message*)data;
command->message_size = messageSize;
command->target_count = targetCount;
memcpy(command->targets, targets, sizeof(messaging_target) * targetCount);
memcpy((char*)command + (dataSize - messageSize), message, messageSize);
// shoot
area->Unlock();
if (wasEmpty)
area->CommitCommand();
return B_OK;
}
// _CommandProcessor
int32
MessagingService::_CommandProcessor()
{
bool commandWaiting = false;
while (!fTerminating) {
// wait for the next command
if (!commandWaiting) {
status_t error = acquire_sem(fCounterSem);
if (error != B_OK)
continue;
} else
commandWaiting = false;
// get it from the first area
MessagingArea *area = fFirstArea;
area->Lock();
while (area->CountCommands() > 0) {
const messaging_command *command = area->PopCommand();
if (!command) {
// something's seriously wrong
ERROR("MessagingService::_CommandProcessor(): area %p (%"
B_PRId32 ") has command count %" B_PRId32 ", but doesn't "
"return any more commands.", area, area->ID(),
area->CountCommands());
break;
}
PRINT("MessagingService::_CommandProcessor(): got command %" B_PRIu32 "\n",
command->command);
// dispatch the command
MessagingCommandHandler *handler
= _GetCommandHandler(command->command);
if (handler) {
handler->HandleMessagingCommand(command->command, command->data,
command->size - sizeof(messaging_command));
} else {
WARNING("MessagingService::_CommandProcessor(): No handler "
"found for command %" B_PRIu32 "\n", command->command);
}
}
// there is a new area we don't know yet
if (!area->NextArea() && area->NextKernelAreaID() >= 0) {
// create it
MessagingArea *nextArea;
status_t error = MessagingArea::Create(area->NextKernelAreaID(),
fLockSem, fCounterSem, nextArea);
if (error == B_OK) {
area->SetNextArea(nextArea);
commandWaiting = true;
} else {
// Bad, but what can we do?
ERROR("MessagingService::_CommandProcessor(): Failed to clone "
"kernel area %" B_PRId32 ": %s\n", area->NextKernelAreaID(),
strerror(error));
}
}
// if the current area is empty and there is a next one, we discard the
// current one
if (area->NextArea() && area->CountCommands() == 0) {
fFirstArea = area->NextArea();
area->Discard();
area->Unlock();
delete area;
} else {
area->Unlock();
}
}
return 0;
}