bool
com_VFSFilter0::start(
__in IOService *provider
)
{
//__asm__ volatile( "int $0x3" );
VNodeMap::Init();
if( kIOReturnSuccess != VFSHookInit() ){
DBG_PRINT_ERROR( ( "VFSHookInit() failed\n" ) );
goto __exit_on_error;
}
if( ! QvrVnodeHooksHashTable::CreateStaticTableWithSize( 8, true ) ){
DBG_PRINT_ERROR( ( "QvrVnodeHooksHashTable::CreateStaticTableWithSize() failed\n" ) );
goto __exit_on_error;
}
//
// gSuperUserContext must have a valid thread and process pointer
// TO DO redesign this! Indefinit holding a thread or task object is a bad behaviour.
//
thread_reference( current_thread() );
task_reference( current_task() );
gSuperUserContext = vfs_context_create(NULL); // vfs_context_kernel()
//
// create an object for the vnodes KAuth callback and register the callback,
// the callback might be called immediatelly just after registration!
//
gVnodeGate = QvrIOKitKAuthVnodeGate::withCallbackRegistration( this );
assert( NULL != gVnodeGate );
if( NULL == gVnodeGate ){
DBG_PRINT_ERROR( ( "QvrIOKitKAuthVnodeGate::withDefaultSettings() failed\n" ) );
goto __exit_on_error;
}
Instance = this;
//
// register with IOKit to allow the class matching
//
registerService();
return true;
__exit_on_error:
//
// all cleanup will be done in stop() and free()
//
this->release();
return false;
}
void
processor_doaction(
processor_t processor)
{
thread_t this_thread;
spl_t s;
register processor_set_t pset;
#if MACH_HOST
register processor_set_t new_pset;
register thread_t thread;
register thread_t prev_thread = THREAD_NULL;
thread_act_t thr_act;
boolean_t have_pset_ref = FALSE;
#endif /* MACH_HOST */
/*
* Get onto the processor to shutdown
*/
this_thread = current_thread();
thread_bind(this_thread, processor);
thread_block((void (*)(void)) 0);
pset = processor->processor_set;
#if MACH_HOST
/*
* If this is the last processor in the processor_set,
* stop all the threads first.
*/
pset_lock(pset);
if (pset->processor_count == 1) {
thread = (thread_t) queue_first(&pset->threads);
prev_thread = THREAD_NULL;
pset->ref_count++;
have_pset_ref = TRUE;
pset->empty = TRUE;
/*
* loop through freezing the processor set assignment
* and reference counting the threads;
*/
while (!queue_end(&pset->threads, (queue_entry_t) thread)) {
thread_reference(thread);
pset_unlock(pset);
/*
* Freeze the thread on the processor set.
* If it's moved, just release the reference.
* Get the next thread in the processor set list
* from the last one which was frozen.
*/
if( thread_stop_freeze(thread, pset) )
prev_thread = thread;
else
thread_deallocate(thread);
pset_lock(pset);
if( prev_thread != THREAD_NULL )
thread = (thread_t)queue_next(&prev_thread->pset_threads);
else
thread = (thread_t) queue_first(&pset->threads);
}
/*
* Remove the processor from the set so that when the threads
* are unstopped below the ones blocked in the kernel don't
* start running again.
*/
s = splsched();
processor_lock(processor);
pset_remove_processor(pset, processor);
/*
* Prevent race with another processor being added to the set
* See code after Restart_pset:
* while(new_pset->empty && new_pset->processor_count > 0)
*
* ... it tests for the condition where a new processor is
* added to the set while the last one is still being removed.
*/
pset->processor_count++; /* block new processors being added */
assert( pset->processor_count == 1 );
/*
* Release the thread assignment locks, unstop the threads and
* release the thread references which were taken above.
*/
thread = (thread_t) queue_first(&pset->threads);
while( !queue_empty( &pset->threads) && (thread != THREAD_NULL) ) {
prev_thread = thread;
if( queue_end(&pset->threads, (queue_entry_t) thread) )
thread = THREAD_NULL;
else
thread = (thread_t) queue_next(&prev_thread->pset_threads);
pset_unlock(pset);
thread_unfreeze(prev_thread);
thread_unstop(prev_thread);
thread_deallocate(prev_thread);
pset_lock(pset);
}
/*
* allow a processor to be added to the empty pset
*/
pset->processor_count--;
}
else {
/* not last processor in set */
#endif /* MACH_HOST */
/*
* At this point, it is ok to rm the processor from the pset.
*/
s = splsched();
processor_lock(processor);
pset_remove_processor(pset, processor);
#if MACH_HOST
}
pset_unlock(pset);
/*
* Copy the next pset pointer into a local variable and clear
* it because we are taking over its reference.
*/
new_pset = processor->processor_set_next;
processor->processor_set_next = PROCESSOR_SET_NULL;
if (processor->state == PROCESSOR_ASSIGN) {
Restart_pset:
/*
* Nasty problem: we want to lock the target pset, but
* we have to enable interrupts to do that which requires
* dropping the processor lock. While the processor
* is unlocked, it could be reassigned or shutdown.
*/
processor_unlock(processor);
splx(s);
/*
* Lock target pset and handle remove last / assign first race.
* Only happens if there is more than one action thread.
*/
pset_lock(new_pset);
while (new_pset->empty && new_pset->processor_count > 0) {
pset_unlock(new_pset);
while (*(volatile boolean_t *)&new_pset->empty &&
*(volatile int *)&new_pset->processor_count > 0)
/* spin */;
pset_lock(new_pset);
}
/*
* Finally relock the processor and see if something changed.
* The only possibilities are assignment to a different pset
* and shutdown.
*/
s = splsched();
processor_lock(processor);
if (processor->state == PROCESSOR_SHUTDOWN) {
pset_unlock(new_pset);
goto shutdown; /* will release pset reference */
}
if (processor->processor_set_next != PROCESSOR_SET_NULL) {
/*
* Processor was reassigned. Drop the reference
* we have on the wrong new_pset, and get the
* right one. Involves lots of lock juggling.
*/
processor_unlock(processor);
splx(s);
pset_unlock(new_pset);
pset_deallocate(new_pset);
s = splsched();
processor_lock(processor);
new_pset = processor->processor_set_next;
processor->processor_set_next = PROCESSOR_SET_NULL;
goto Restart_pset;
}
/*
* If the pset has been deactivated since the operation
* was requested, redirect to the default pset.
*/
if (!(new_pset->active)) {
pset_unlock(new_pset);
pset_deallocate(new_pset);
new_pset = &default_pset;
pset_lock(new_pset);
new_pset->ref_count++;
}
/*
* Do assignment, then wakeup anyone waiting for it.
* Finally context switch to have it take effect.
*/
pset_add_processor(new_pset, processor);
if (new_pset->empty) {
/*
* Set all the threads loose
*/
thread = (thread_t) queue_first(&new_pset->threads);
while (!queue_end(&new_pset->threads,(queue_entry_t)thread)) {
thr_act = thread_lock_act(thread);
thread_release(thread->top_act);
act_unlock_thread(thr_act);
thread = (thread_t) queue_next(&thread->pset_threads);
}
new_pset->empty = FALSE;
}
processor->processor_set_next = PROCESSOR_SET_NULL;
processor->state = PROCESSOR_RUNNING;
thread_wakeup((event_t)processor);
processor_unlock(processor);
splx(s);
pset_unlock(new_pset);
/*
* Clean up dangling references, and release our binding.
*/
pset_deallocate(new_pset);
if (have_pset_ref)
pset_deallocate(pset);
if (prev_thread != THREAD_NULL)
thread_deallocate(prev_thread);
thread_bind(this_thread, PROCESSOR_NULL);
thread_block((void (*)(void)) 0);
return;
}
shutdown:
#endif /* MACH_HOST */
/*
* Do shutdown, make sure we live when processor dies.
*/
if (processor->state != PROCESSOR_SHUTDOWN) {
printf("state: %d\n", processor->state);
panic("action_thread -- bad processor state");
}
processor_unlock(processor);
/*
* Clean up dangling references, and release our binding.
*/
#if MACH_HOST
if (new_pset != PROCESSOR_SET_NULL)
pset_deallocate(new_pset);
if (have_pset_ref)
pset_deallocate(pset);
if (prev_thread != THREAD_NULL)
thread_deallocate(prev_thread);
#endif /* MACH_HOST */
thread_bind(this_thread, PROCESSOR_NULL);
switch_to_shutdown_context(this_thread,
processor_doshutdown,
processor);
splx(s);
}
/*
* task_swap_swapout_thread: [exported]
*
* Executes as a separate kernel thread.
* Its job is to swap out threads that have been halted by AST_SWAPOUT.
*/
void
task_swap_swapout_thread(void)
{
thread_act_t thr_act;
thread_t thread, nthread;
task_t task;
int s;
thread_swappable(current_act(), FALSE);
stack_privilege(current_thread());
spllo();
while (TRUE) {
task_swapper_lock();
while (! queue_empty(&swapout_thread_q)) {
queue_remove_first(&swapout_thread_q, thr_act,
thread_act_t, swap_queue);
/*
* If we're racing with task_swapin, we need
* to make it safe for it to do remque on the
* thread, so make its links point to itself.
* Allowing this ugliness is cheaper than
* making task_swapin search the entire queue.
*/
act_lock(thr_act);
queue_init((queue_t) &thr_act->swap_queue);
act_unlock(thr_act);
task_swapper_unlock();
/*
* Wait for thread's RUN bit to be deasserted.
*/
thread = act_lock_thread(thr_act);
if (thread == THREAD_NULL)
act_unlock_thread(thr_act);
else {
boolean_t r;
thread_reference(thread);
thread_hold(thr_act);
act_unlock_thread(thr_act);
r = thread_stop_wait(thread);
nthread = act_lock_thread(thr_act);
thread_release(thr_act);
thread_deallocate(thread);
act_unlock_thread(thr_act);
if (!r || nthread != thread) {
task_swapper_lock();
continue;
}
}
task = thr_act->task;
task_lock(task);
/*
* we can race with swapin, which would set the
* state to TASK_SW_IN.
*/
if ((task->swap_state != TASK_SW_OUT) &&
(task->swap_state != TASK_SW_GOING_OUT)) {
task_unlock(task);
task_swapper_lock();
TASK_STATS_INCR(task_sw_race_in_won);
if (thread != THREAD_NULL)
thread_unstop(thread);
continue;
}
nthread = act_lock_thread(thr_act);
if (nthread != thread || thr_act->active == FALSE) {
act_unlock_thread(thr_act);
task_unlock(task);
task_swapper_lock();
TASK_STATS_INCR(task_sw_act_inactive);
if (thread != THREAD_NULL)
thread_unstop(thread);
continue;
}
s = splsched();
if (thread != THREAD_NULL)
thread_lock(thread);
/*
* Thread cannot have been swapped out yet because
* TH_SW_TASK_SWAPPING was set in AST. If task_swapin
* beat us here, we either wouldn't have found it on
* the queue, or the task->swap_state would have
* changed. The synchronization is on the
* task's swap_state and the task_lock.
* The thread can't be swapped in any other way
* because its task has been swapped.
*/
assert(thr_act->swap_state & TH_SW_TASK_SWAPPING);
assert(thread == THREAD_NULL ||
!(thread->state & (TH_SWAPPED_OUT|TH_RUN)));
assert((thr_act->swap_state & TH_SW_STATE) == TH_SW_IN);
/* assert(thread->state & TH_HALTED); */
/* this also clears TH_SW_TASK_SWAPPING flag */
thr_act->swap_state = TH_SW_GOING_OUT;
if (thread != THREAD_NULL) {
if (thread->top_act == thr_act) {
thread->state |= TH_SWAPPED_OUT;
/*
* Once we unlock the task, things can happen
* to the thread, so make sure it's consistent
* for thread_swapout.
*/
}
thread->ref_count++;
thread_unlock(thread);
thread_unstop(thread);
}
splx(s);
act_locked_act_reference(thr_act);
act_unlock_thread(thr_act);
task_unlock(task);
thread_swapout(thr_act); /* do the work */
if (thread != THREAD_NULL)
thread_deallocate(thread);
act_deallocate(thr_act);
task_swapper_lock();
}
assert_wait((event_t)&swapout_thread_q, FALSE);
task_swapper_unlock();
thread_block((void (*)(void)) 0);
}
}
