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/*
* Copyright (c) 2018-2021, Andreas Kling <kling@serenityos.org>
*
* SPDX-License-Identifier: BSD-2-Clause
*/
#include <AK/Checked.h>
#include <Kernel/Memory/MemoryManager.h>
#include <Kernel/Tasks/PerformanceManager.h>
#include <Kernel/Tasks/Process.h>
#include <Kernel/Tasks/Scheduler.h>
namespace Kernel {
ErrorOr<FlatPtr> Process::sys$create_thread(void* (*entry)(void*), Userspace<Syscall::SC_create_thread_params const*> user_params)
{
VERIFY_PROCESS_BIG_LOCK_ACQUIRED(this);
TRY(require_promise(Pledge::thread));
auto params = TRY(copy_typed_from_user(user_params));
unsigned detach_state = params.detach_state;
int schedule_priority = params.schedule_priority;
unsigned stack_size = params.stack_size;
auto user_sp = Checked<FlatPtr>((FlatPtr)params.stack_location);
user_sp += stack_size;
if (user_sp.has_overflow())
return EOVERFLOW;
TRY(address_space().with([&](auto& space) -> ErrorOr<void> {
if (!MM.validate_user_stack(*space, VirtualAddress(user_sp.value() - 4)))
return EFAULT;
return {};
}));
// FIXME: return EAGAIN if Thread::all_threads().size() is greater than PTHREAD_THREADS_MAX
int requested_thread_priority = schedule_priority;
if (requested_thread_priority < THREAD_PRIORITY_MIN || requested_thread_priority > THREAD_PRIORITY_MAX)
return EINVAL;
bool is_thread_joinable = (0 == detach_state);
// FIXME: Do something with guard pages?
auto thread = TRY(Thread::create(*this));
// We know this thread is not the main_thread,
// So give it a unique name until the user calls $set_thread_name on it
auto new_thread_name = TRY(name().with([&](auto& process_name) {
return KString::formatted("{} [{}]", process_name->view(), thread->tid().value());
}));
thread->set_name(move(new_thread_name));
if (!is_thread_joinable)
thread->detach();
auto& regs = thread->regs();
regs.set_ip((FlatPtr)entry);
regs.set_sp(user_sp.value());
#if ARCH(X86_64)
regs.set_flags(0x0202);
regs.cr3 = address_space().with([](auto& space) { return space->page_directory().cr3(); });
// Set up the argument registers expected by pthread_create_helper.
regs.rdi = (FlatPtr)params.entry;
regs.rsi = (FlatPtr)params.entry_argument;
regs.rdx = (FlatPtr)params.stack_location;
regs.rcx = (FlatPtr)params.stack_size;
#elif ARCH(AARCH64)
regs.ttbr0_el1 = address_space().with([](auto& space) { return space->page_directory().ttbr0(); });
// Set up the argument registers expected by pthread_create_helper.
regs.x[0] = (FlatPtr)params.entry;
regs.x[1] = (FlatPtr)params.entry_argument;
regs.x[2] = (FlatPtr)params.stack_location;
regs.x[3] = (FlatPtr)params.stack_size;
#else
# error Unknown architecture
#endif
TRY(thread->make_thread_specific_region({}));
PerformanceManager::add_thread_created_event(*thread);
SpinlockLocker lock(g_scheduler_lock);
thread->set_priority(requested_thread_priority);
thread->set_state(Thread::State::Runnable);
return thread->tid().value();
}
void Process::sys$exit_thread(Userspace<void*> exit_value, Userspace<void*> stack_location, size_t stack_size)
{
VERIFY_PROCESS_BIG_LOCK_ACQUIRED(this);
auto result = require_promise(Pledge::thread);
if (result.is_error()) {
// Crash now, as we will never reach back to the syscall handler.
crash(SIGABRT, {});
}
if (this->thread_count() == 1) {
// If this is the last thread, instead kill the process.
this->sys$exit(0);
}
auto* current_thread = Thread::current();
current_thread->set_profiling_suppressed();
PerformanceManager::add_thread_exit_event(*current_thread);
if (stack_location) {
auto unmap_result = address_space().with([&](auto& space) {
return space->unmap_mmap_range(stack_location.vaddr(), stack_size);
});
if (unmap_result.is_error())
dbgln("Failed to unmap thread stack, terminating thread anyway. Error code: {}", unmap_result.error());
}
current_thread->exit(reinterpret_cast<void*>(exit_value.ptr()));
VERIFY_NOT_REACHED();
}
ErrorOr<FlatPtr> Process::sys$detach_thread(pid_t tid)
{
VERIFY_PROCESS_BIG_LOCK_ACQUIRED(this);
TRY(require_promise(Pledge::thread));
auto thread = Thread::from_tid(tid);
if (!thread || thread->pid() != pid())
return ESRCH;
if (!thread->is_joinable())
return EINVAL;
thread->detach();
return 0;
}
ErrorOr<FlatPtr> Process::sys$join_thread(pid_t tid, Userspace<void**> exit_value)
{
VERIFY_PROCESS_BIG_LOCK_ACQUIRED(this);
TRY(require_promise(Pledge::thread));
auto thread = Thread::from_tid(tid);
if (!thread || thread->pid() != pid())
return ESRCH;
auto* current_thread = Thread::current();
if (thread == current_thread)
return EDEADLK;
void* joinee_exit_value = nullptr;
// NOTE: pthread_join() cannot be interrupted by signals. Only by death.
for (;;) {
ErrorOr<void> try_join_result;
auto result = current_thread->block<Thread::JoinBlocker>({}, *thread, try_join_result, joinee_exit_value);
if (result == Thread::BlockResult::NotBlocked) {
if (try_join_result.is_error())
return try_join_result.release_error();
break;
}
if (result == Thread::BlockResult::InterruptedByDeath)
break;
dbgln("join_thread: retrying");
}
if (exit_value)
TRY(copy_to_user(exit_value, &joinee_exit_value));
return 0;
}
ErrorOr<FlatPtr> Process::sys$kill_thread(pid_t tid, int signal)
{
VERIFY_PROCESS_BIG_LOCK_ACQUIRED(this);
TRY(require_promise(Pledge::thread));
if (signal < 0 || signal >= NSIG)
return EINVAL;
auto thread = Thread::from_tid(tid);
if (!thread || thread->pid() != pid())
return ESRCH;
if (signal != 0)
thread->send_signal(signal, &Process::current());
return 0;
}
ErrorOr<FlatPtr> Process::sys$set_thread_name(pid_t tid, Userspace<char const*> user_name, size_t user_name_length)
{
VERIFY_NO_PROCESS_BIG_LOCK(this);
TRY(require_promise(Pledge::stdio));
auto name = TRY(try_copy_kstring_from_user(user_name, user_name_length));
const size_t max_thread_name_size = 64;
if (name->length() > max_thread_name_size)
return ENAMETOOLONG;
auto thread = Thread::from_tid(tid);
if (!thread || thread->pid() != pid())
return ESRCH;
thread->set_name(move(name));
return 0;
}
ErrorOr<FlatPtr> Process::sys$get_thread_name(pid_t tid, Userspace<char*> buffer, size_t buffer_size)
{
VERIFY_NO_PROCESS_BIG_LOCK(this);
TRY(require_promise(Pledge::thread));
if (buffer_size == 0)
return EINVAL;
auto thread = Thread::from_tid(tid);
if (!thread || thread->pid() != pid())
return ESRCH;
TRY(thread->name().with([&](auto& thread_name) -> ErrorOr<void> {
if (thread_name->view().is_null()) {
char null_terminator = '\0';
TRY(copy_to_user(buffer, &null_terminator, sizeof(null_terminator)));
return {};
}
if (thread_name->length() + 1 > buffer_size)
return ENAMETOOLONG;
return copy_to_user(buffer, thread_name->characters(), thread_name->length() + 1);
}));
return 0;
}
ErrorOr<FlatPtr> Process::sys$gettid()
{
VERIFY_NO_PROCESS_BIG_LOCK(this);
TRY(require_promise(Pledge::stdio));
return Thread::current()->tid().value();
}
}
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