serenity/Kernel/Thread.cpp
Andreas Kling c1bbd40b9e Kernel: Rename "descriptor" to "description" where appropriate.
Now that FileDescription is called that, variables of that type should not
be called "descriptor". This is kinda wordy but we'll get used to it.
2019-06-13 22:03:04 +02:00

586 lines
17 KiB
C++

#include <Kernel/FileSystem/FileDescription.h>
#include <Kernel/Process.h>
#include <Kernel/Scheduler.h>
#include <Kernel/Thread.h>
#include <Kernel/VM/MemoryManager.h>
#include <LibC/signal_numbers.h>
//#define SIGNAL_DEBUG
HashTable<Thread*>& thread_table()
{
ASSERT_INTERRUPTS_DISABLED();
static HashTable<Thread*>* table;
if (!table)
table = new HashTable<Thread*>;
return *table;
}
InlineLinkedList<Thread>* g_runnable_threads;
InlineLinkedList<Thread>* g_nonrunnable_threads;
static const dword default_kernel_stack_size = 65536;
static const dword default_userspace_stack_size = 65536;
Thread::Thread(Process& process)
: m_process(process)
, m_tid(process.m_next_tid++)
{
dbgprintf("Thread{%p}: New thread TID=%u in %s(%u)\n", this, m_tid, process.name().characters(), process.pid());
set_default_signal_dispositions();
m_fpu_state = (FPUState*)kmalloc_aligned(sizeof(FPUState), 16);
memset(&m_tss, 0, sizeof(m_tss));
// Only IF is set when a process boots.
m_tss.eflags = 0x0202;
word cs, ds, ss;
if (m_process.is_ring0()) {
cs = 0x08;
ds = 0x10;
ss = 0x10;
} else {
cs = 0x1b;
ds = 0x23;
ss = 0x23;
}
m_tss.ds = ds;
m_tss.es = ds;
m_tss.fs = ds;
m_tss.gs = ds;
m_tss.ss = ss;
m_tss.cs = cs;
m_tss.cr3 = m_process.page_directory().cr3();
if (m_process.is_ring0()) {
// FIXME: This memory is leaked.
// But uh, there's also no kernel process termination, so I guess it's not technically leaked...
m_kernel_stack_base = (dword)kmalloc_eternal(default_kernel_stack_size);
m_tss.esp = (m_kernel_stack_base + default_kernel_stack_size) & 0xfffffff8u;
} else {
// Ring3 processes need a separate stack for Ring0.
m_kernel_stack_region = MM.allocate_kernel_region(default_kernel_stack_size, String::format("Kernel Stack (Thread %d)", m_tid));
m_kernel_stack_base = m_kernel_stack_region->vaddr().get();
m_tss.ss0 = 0x10;
m_tss.esp0 = m_kernel_stack_region->vaddr().offset(default_kernel_stack_size).get() & 0xfffffff8u;
}
// HACK: Ring2 SS in the TSS is the current PID.
m_tss.ss2 = m_process.pid();
m_far_ptr.offset = 0x98765432;
if (m_process.pid() != 0) {
InterruptDisabler disabler;
thread_table().set(this);
set_thread_list(g_nonrunnable_threads);
}
}
Thread::~Thread()
{
dbgprintf("~Thread{%p}\n", this);
kfree_aligned(m_fpu_state);
{
InterruptDisabler disabler;
if (m_thread_list)
m_thread_list->remove(this);
thread_table().remove(this);
}
if (g_last_fpu_thread == this)
g_last_fpu_thread = nullptr;
if (selector())
gdt_free_entry(selector());
}
void Thread::unblock()
{
m_blocked_description = nullptr;
if (current == this) {
set_state(Thread::Running);
return;
}
ASSERT(m_state != Thread::Runnable && m_state != Thread::Running);
set_state(Thread::Runnable);
}
void Thread::snooze_until(Alarm& alarm)
{
m_snoozing_alarm = &alarm;
block(Thread::BlockedSnoozing);
Scheduler::yield();
}
void Thread::block(Thread::State new_state)
{
bool did_unlock = process().big_lock().unlock_if_locked();
if (state() != Thread::Running) {
kprintf("Thread::block: %s(%u) block(%u/%s) with state=%u/%s\n", process().name().characters(), process().pid(), new_state, to_string(new_state), state(), to_string(state()));
}
ASSERT(state() == Thread::Running);
m_was_interrupted_while_blocked = false;
set_state(new_state);
Scheduler::yield();
if (did_unlock)
process().big_lock().lock();
}
void Thread::block(Thread::State new_state, FileDescription& description)
{
m_blocked_description = &description;
block(new_state);
}
void Thread::sleep(dword ticks)
{
ASSERT(state() == Thread::Running);
current->set_wakeup_time(g_uptime + ticks);
current->block(Thread::BlockedSleep);
}
const char* to_string(Thread::State state)
{
switch (state) {
case Thread::Invalid:
return "Invalid";
case Thread::Runnable:
return "Runnable";
case Thread::Running:
return "Running";
case Thread::Dying:
return "Dying";
case Thread::Dead:
return "Dead";
case Thread::Stopped:
return "Stopped";
case Thread::Skip1SchedulerPass:
return "Skip1";
case Thread::Skip0SchedulerPasses:
return "Skip0";
case Thread::BlockedSleep:
return "Sleep";
case Thread::BlockedWait:
return "Wait";
case Thread::BlockedRead:
return "Read";
case Thread::BlockedWrite:
return "Write";
case Thread::BlockedSignal:
return "Signal";
case Thread::BlockedSelect:
return "Select";
case Thread::BlockedLurking:
return "Lurking";
case Thread::BlockedConnect:
return "Connect";
case Thread::BlockedReceive:
return "Receive";
case Thread::BlockedSnoozing:
return "Snoozing";
}
kprintf("to_string(Thread::State): Invalid state: %u\n", state);
ASSERT_NOT_REACHED();
return nullptr;
}
void Thread::finalize()
{
dbgprintf("Finalizing Thread %u in %s(%u)\n", tid(), m_process.name().characters(), pid());
set_state(Thread::State::Dead);
m_blocked_description = nullptr;
if (this == &m_process.main_thread())
m_process.finalize();
}
void Thread::finalize_dying_threads()
{
Vector<Thread*, 32> dying_threads;
{
InterruptDisabler disabler;
for_each_in_state(Thread::State::Dying, [&](Thread& thread) {
dying_threads.append(&thread);
});
}
for (auto* thread : dying_threads)
thread->finalize();
}
bool Thread::tick()
{
++m_ticks;
if (tss().cs & 3)
++m_process.m_ticks_in_user;
else
++m_process.m_ticks_in_kernel;
return --m_ticks_left;
}
void Thread::send_signal(byte signal, Process* sender)
{
ASSERT(signal < 32);
if (sender)
dbgprintf("signal: %s(%u) sent %d to %s(%u)\n", sender->name().characters(), sender->pid(), signal, process().name().characters(), pid());
else
dbgprintf("signal: kernel sent %d to %s(%u)\n", signal, process().name().characters(), pid());
InterruptDisabler disabler;
m_pending_signals |= 1 << signal;
}
bool Thread::has_unmasked_pending_signals() const
{
return m_pending_signals & ~m_signal_mask;
}
ShouldUnblockThread Thread::dispatch_one_pending_signal()
{
ASSERT_INTERRUPTS_DISABLED();
dword signal_candidates = m_pending_signals & ~m_signal_mask;
ASSERT(signal_candidates);
byte signal = 0;
for (; signal < 32; ++signal) {
if (signal_candidates & (1 << signal)) {
break;
}
}
return dispatch_signal(signal);
}
enum class DefaultSignalAction {
Terminate,
Ignore,
DumpCore,
Stop,
Continue,
};
DefaultSignalAction default_signal_action(byte signal)
{
ASSERT(signal && signal < NSIG);
switch (signal) {
case SIGHUP:
case SIGINT:
case SIGKILL:
case SIGPIPE:
case SIGALRM:
case SIGUSR1:
case SIGUSR2:
case SIGVTALRM:
case SIGSTKFLT:
case SIGIO:
case SIGPROF:
case SIGTERM:
case SIGPWR:
return DefaultSignalAction::Terminate;
case SIGCHLD:
case SIGURG:
case SIGWINCH:
return DefaultSignalAction::Ignore;
case SIGQUIT:
case SIGILL:
case SIGTRAP:
case SIGABRT:
case SIGBUS:
case SIGFPE:
case SIGSEGV:
case SIGXCPU:
case SIGXFSZ:
case SIGSYS:
return DefaultSignalAction::DumpCore;
case SIGCONT:
return DefaultSignalAction::Continue;
case SIGSTOP:
case SIGTSTP:
case SIGTTIN:
case SIGTTOU:
return DefaultSignalAction::Stop;
}
ASSERT_NOT_REACHED();
}
ShouldUnblockThread Thread::dispatch_signal(byte signal)
{
ASSERT_INTERRUPTS_DISABLED();
ASSERT(signal < 32);
#ifdef SIGNAL_DEBUG
kprintf("dispatch_signal %s(%u) <- %u\n", process().name().characters(), pid(), signal);
#endif
auto& action = m_signal_action_data[signal];
// FIXME: Implement SA_SIGINFO signal handlers.
ASSERT(!(action.flags & SA_SIGINFO));
// Mark this signal as handled.
m_pending_signals &= ~(1 << signal);
if (signal == SIGSTOP) {
set_state(Stopped);
return ShouldUnblockThread::No;
}
if (signal == SIGCONT && state() == Stopped)
set_state(Runnable);
auto handler_vaddr = action.handler_or_sigaction;
if (handler_vaddr.is_null()) {
switch (default_signal_action(signal)) {
case DefaultSignalAction::Stop:
set_state(Stopped);
return ShouldUnblockThread::No;
case DefaultSignalAction::DumpCore:
case DefaultSignalAction::Terminate:
m_process.terminate_due_to_signal(signal);
return ShouldUnblockThread::No;
case DefaultSignalAction::Ignore:
if (state() == BlockedSignal)
set_state(Runnable);
return ShouldUnblockThread::No;
case DefaultSignalAction::Continue:
return ShouldUnblockThread::Yes;
}
ASSERT_NOT_REACHED();
}
if (handler_vaddr.as_ptr() == SIG_IGN) {
#ifdef SIGNAL_DEBUG
kprintf("%s(%u) ignored signal %u\n", process().name().characters(), pid(), signal);
#endif
return ShouldUnblockThread::Yes;
}
dword old_signal_mask = m_signal_mask;
dword new_signal_mask = action.mask;
if (action.flags & SA_NODEFER)
new_signal_mask &= ~(1 << signal);
else
new_signal_mask |= 1 << signal;
m_signal_mask |= new_signal_mask;
Scheduler::prepare_to_modify_tss(*this);
word ret_cs = m_tss.cs;
dword ret_eip = m_tss.eip;
dword ret_eflags = m_tss.eflags;
bool interrupting_in_kernel = (ret_cs & 3) == 0;
ProcessPagingScope paging_scope(m_process);
m_process.create_signal_trampolines_if_needed();
if (interrupting_in_kernel) {
#ifdef SIGNAL_DEBUG
kprintf("dispatch_signal to %s(%u) in state=%s with return to %w:%x\n", process().name().characters(), pid(), to_string(state()), ret_cs, ret_eip);
#endif
ASSERT(is_blocked());
m_tss_to_resume_kernel = make<TSS32>(m_tss);
#ifdef SIGNAL_DEBUG
kprintf("resume tss pc: %w:%x stack: %w:%x flags: %x cr3: %x\n", m_tss_to_resume_kernel->cs, m_tss_to_resume_kernel->eip, m_tss_to_resume_kernel->ss, m_tss_to_resume_kernel->esp, m_tss_to_resume_kernel->eflags, m_tss_to_resume_kernel->cr3);
#endif
if (!m_signal_stack_user_region) {
m_signal_stack_user_region = m_process.allocate_region(VirtualAddress(), default_userspace_stack_size, String::format("User Signal Stack (Thread %d)", m_tid));
ASSERT(m_signal_stack_user_region);
}
if (!m_kernel_stack_for_signal_handler_region)
m_kernel_stack_for_signal_handler_region = MM.allocate_kernel_region(default_kernel_stack_size, String::format("Kernel Signal Stack (Thread %d)", m_tid));
m_tss.ss = 0x23;
m_tss.esp = m_signal_stack_user_region->vaddr().offset(default_userspace_stack_size).get();
m_tss.ss0 = 0x10;
m_tss.esp0 = m_kernel_stack_for_signal_handler_region->vaddr().offset(default_kernel_stack_size).get();
push_value_on_stack(0);
} else {
push_value_on_stack(ret_eip);
push_value_on_stack(ret_eflags);
// PUSHA
dword old_esp = m_tss.esp;
push_value_on_stack(m_tss.eax);
push_value_on_stack(m_tss.ecx);
push_value_on_stack(m_tss.edx);
push_value_on_stack(m_tss.ebx);
push_value_on_stack(old_esp);
push_value_on_stack(m_tss.ebp);
push_value_on_stack(m_tss.esi);
push_value_on_stack(m_tss.edi);
// Align the stack.
m_tss.esp -= 12;
}
// PUSH old_signal_mask
push_value_on_stack(old_signal_mask);
m_tss.cs = 0x1b;
m_tss.ds = 0x23;
m_tss.es = 0x23;
m_tss.fs = 0x23;
m_tss.gs = 0x23;
m_tss.eip = handler_vaddr.get();
// FIXME: Should we worry about the stack being 16 byte aligned when entering a signal handler?
push_value_on_stack(signal);
if (interrupting_in_kernel)
push_value_on_stack(m_process.m_return_to_ring0_from_signal_trampoline.get());
else
push_value_on_stack(m_process.m_return_to_ring3_from_signal_trampoline.get());
ASSERT((m_tss.esp % 16) == 0);
// FIXME: This state is such a hack. It avoids trouble if 'current' is the process receiving a signal.
set_state(Skip1SchedulerPass);
#ifdef SIGNAL_DEBUG
kprintf("signal: Okay, %s(%u) {%s} has been primed with signal handler %w:%x\n", process().name().characters(), pid(), to_string(state()), m_tss.cs, m_tss.eip);
#endif
return ShouldUnblockThread::Yes;
}
void Thread::set_default_signal_dispositions()
{
// FIXME: Set up all the right default actions. See signal(7).
memset(&m_signal_action_data, 0, sizeof(m_signal_action_data));
m_signal_action_data[SIGCHLD].handler_or_sigaction = VirtualAddress((dword)SIG_IGN);
m_signal_action_data[SIGWINCH].handler_or_sigaction = VirtualAddress((dword)SIG_IGN);
}
void Thread::push_value_on_stack(dword value)
{
m_tss.esp -= 4;
dword* stack_ptr = (dword*)m_tss.esp;
*stack_ptr = value;
}
void Thread::make_userspace_stack_for_main_thread(Vector<String> arguments, Vector<String> environment)
{
auto* region = m_process.allocate_region(VirtualAddress(), default_userspace_stack_size, "Stack (Main thread)");
ASSERT(region);
m_tss.esp = region->vaddr().offset(default_userspace_stack_size).get();
char* stack_base = (char*)region->vaddr().get();
int argc = arguments.size();
char** argv = (char**)stack_base;
char** env = argv + arguments.size() + 1;
char* bufptr = stack_base + (sizeof(char*) * (arguments.size() + 1)) + (sizeof(char*) * (environment.size() + 1));
size_t total_blob_size = 0;
for (auto& a : arguments)
total_blob_size += a.length() + 1;
for (auto& e : environment)
total_blob_size += e.length() + 1;
size_t total_meta_size = sizeof(char*) * (arguments.size() + 1) + sizeof(char*) * (environment.size() + 1);
// FIXME: It would be better if this didn't make us panic.
ASSERT((total_blob_size + total_meta_size) < default_userspace_stack_size);
for (int i = 0; i < arguments.size(); ++i) {
argv[i] = bufptr;
memcpy(bufptr, arguments[i].characters(), arguments[i].length());
bufptr += arguments[i].length();
*(bufptr++) = '\0';
}
argv[arguments.size()] = nullptr;
for (int i = 0; i < environment.size(); ++i) {
env[i] = bufptr;
memcpy(bufptr, environment[i].characters(), environment[i].length());
bufptr += environment[i].length();
*(bufptr++) = '\0';
}
env[environment.size()] = nullptr;
// NOTE: The stack needs to be 16-byte aligned.
push_value_on_stack((dword)env);
push_value_on_stack((dword)argv);
push_value_on_stack((dword)argc);
push_value_on_stack(0);
}
void Thread::make_userspace_stack_for_secondary_thread(void* argument)
{
auto* region = m_process.allocate_region(VirtualAddress(), default_userspace_stack_size, String::format("Stack (Thread %d)", tid()));
ASSERT(region);
m_tss.esp = region->vaddr().offset(default_userspace_stack_size).get();
// NOTE: The stack needs to be 16-byte aligned.
push_value_on_stack((dword)argument);
push_value_on_stack(0);
}
Thread* Thread::clone(Process& process)
{
auto* clone = new Thread(process);
memcpy(clone->m_signal_action_data, m_signal_action_data, sizeof(m_signal_action_data));
clone->m_signal_mask = m_signal_mask;
clone->m_fpu_state = (FPUState*)kmalloc_aligned(sizeof(FPUState), 16);
memcpy(clone->m_fpu_state, m_fpu_state, sizeof(FPUState));
clone->m_has_used_fpu = m_has_used_fpu;
return clone;
}
KResult Thread::wait_for_connect(FileDescription& description)
{
ASSERT(description.is_socket());
auto& socket = *description.socket();
if (socket.is_connected())
return KSuccess;
block(Thread::State::BlockedConnect, description);
Scheduler::yield();
if (!socket.is_connected())
return KResult(-ECONNREFUSED);
return KSuccess;
}
void Thread::initialize()
{
g_runnable_threads = new InlineLinkedList<Thread>;
g_nonrunnable_threads = new InlineLinkedList<Thread>;
Scheduler::initialize();
}
Vector<Thread*> Thread::all_threads()
{
Vector<Thread*> threads;
InterruptDisabler disabler;
threads.ensure_capacity(thread_table().size());
for (auto* thread : thread_table())
threads.unchecked_append(thread);
return threads;
}
bool Thread::is_thread(void* ptr)
{
ASSERT_INTERRUPTS_DISABLED();
return thread_table().contains((Thread*)ptr);
}
void Thread::set_thread_list(InlineLinkedList<Thread>* thread_list)
{
ASSERT(pid() != 0);
if (m_thread_list == thread_list)
return;
if (m_thread_list)
m_thread_list->remove(this);
if (thread_list)
thread_list->append(this);
m_thread_list = thread_list;
}
void Thread::set_state(State new_state)
{
m_state = new_state;
if (m_process.pid() != 0)
set_thread_list(thread_list_for_state(new_state));
}