ladybird/Kernel/Syscalls/thread.cpp
Andreas Kling 79fa9765ca Kernel: Replace KResult and KResultOr<T> with Error and ErrorOr<T>
We now use AK::Error and AK::ErrorOr<T> in both kernel and userspace!
This was a slightly tedious refactoring that took a long time, so it's
not unlikely that some bugs crept in.

Nevertheless, it does pass basic functionality testing, and it's just
real nice to finally see the same pattern in all contexts. :^)
2021-11-08 01:10:53 +01:00

225 lines
6.6 KiB
C++

/*
* Copyright (c) 2018-2021, Andreas Kling <kling@serenityos.org>
*
* SPDX-License-Identifier: BSD-2-Clause
*/
#include <AK/Checked.h>
#include <AK/String.h>
#include <AK/StringBuilder.h>
#include <Kernel/Memory/MemoryManager.h>
#include <Kernel/PerformanceManager.h>
#include <Kernel/Process.h>
namespace Kernel {
ErrorOr<FlatPtr> Process::sys$create_thread(void* (*entry)(void*), Userspace<const Syscall::SC_create_thread_params*> user_params)
{
VERIFY_PROCESS_BIG_LOCK_ACQUIRED(this)
REQUIRE_PROMISE(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;
if (!MM.validate_user_stack(this->address_space(), VirtualAddress(user_sp.value() - 4)))
return EFAULT;
// 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::try_create(*this));
// FIXME: Don't make a temporary String here
auto new_thread_name = TRY(KString::try_create(String::formatted("{} [{}]", m_name, thread->tid().value())));
// We know this thread is not the main_thread,
// So give it a unique name until the user calls $set_thread_name on it
// length + 4 to give space for our extra junk at the end
StringBuilder builder(m_name->length() + 4);
thread->set_name(move(new_thread_name));
if (!is_thread_joinable)
thread->detach();
auto& regs = thread->regs();
regs.set_ip((FlatPtr)entry);
regs.set_flags(0x0202);
regs.set_sp(user_sp.value());
#if ARCH(X86_64)
regs.rdi = params.rdi;
regs.rsi = params.rsi;
regs.rdx = params.rdx;
regs.rcx = params.rcx;
#endif
regs.cr3 = address_space().page_directory().cr3();
TRY(thread->make_thread_specific_region({}));
PerformanceManager::add_thread_created_event(*thread);
SpinlockLocker lock(g_scheduler_lock);
thread->set_priority(requested_thread_priority);
thread->set_state(Thread::State::Runnable);
return thread->tid().value();
}
void Process::sys$exit_thread(Userspace<void*> exit_value, Userspace<void*> stack_location, size_t stack_size)
{
VERIFY_PROCESS_BIG_LOCK_ACQUIRED(this)
REQUIRE_PROMISE(thread);
if (this->thread_count() == 1) {
// If this is the last thread, instead kill the process.
this->sys$exit(0);
}
auto current_thread = Thread::current();
current_thread->set_profiling_suppressed();
PerformanceManager::add_thread_exit_event(*current_thread);
if (stack_location) {
auto unmap_result = address_space().unmap_mmap_range(VirtualAddress { stack_location }, stack_size);
if (unmap_result.is_error())
dbgln("Failed to unmap thread stack, terminating thread anyway. Error code: {}", unmap_result.error());
}
current_thread->exit(reinterpret_cast<void*>(exit_value.ptr()));
VERIFY_NOT_REACHED();
}
ErrorOr<FlatPtr> Process::sys$detach_thread(pid_t tid)
{
VERIFY_PROCESS_BIG_LOCK_ACQUIRED(this)
REQUIRE_PROMISE(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$join_thread(pid_t tid, Userspace<void**> exit_value)
{
VERIFY_PROCESS_BIG_LOCK_ACQUIRED(this)
REQUIRE_PROMISE(thread);
auto thread = Thread::from_tid(tid);
if (!thread || thread->pid() != pid())
return ESRCH;
auto current_thread = Thread::current();
if (thread == current_thread)
return EDEADLK;
void* joinee_exit_value = nullptr;
// NOTE: pthread_join() cannot be interrupted by signals. Only by death.
for (;;) {
ErrorOr<void> try_join_result;
auto result = current_thread->block<Thread::JoinBlocker>({}, *thread, try_join_result, joinee_exit_value);
if (result == Thread::BlockResult::NotBlocked) {
if (try_join_result.is_error())
return try_join_result.release_error();
break;
}
if (result == Thread::BlockResult::InterruptedByDeath)
break;
dbgln("join_thread: retrying");
}
if (exit_value)
TRY(copy_to_user(exit_value, &joinee_exit_value));
return 0;
}
ErrorOr<FlatPtr> Process::sys$kill_thread(pid_t tid, int signal)
{
VERIFY_PROCESS_BIG_LOCK_ACQUIRED(this)
REQUIRE_PROMISE(thread);
if (signal < 0 || signal >= 32)
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$set_thread_name(pid_t tid, Userspace<const char*> user_name, size_t user_name_length)
{
VERIFY_PROCESS_BIG_LOCK_ACQUIRED(this)
REQUIRE_PROMISE(stdio);
auto name = TRY(try_copy_kstring_from_user(user_name, user_name_length));
const size_t max_thread_name_size = 64;
if (name->length() > max_thread_name_size)
return EINVAL;
auto thread = Thread::from_tid(tid);
if (!thread || thread->pid() != pid())
return ESRCH;
thread->set_name(move(name));
return 0;
}
ErrorOr<FlatPtr> Process::sys$get_thread_name(pid_t tid, Userspace<char*> buffer, size_t buffer_size)
{
VERIFY_PROCESS_BIG_LOCK_ACQUIRED(this)
REQUIRE_PROMISE(thread);
if (buffer_size == 0)
return EINVAL;
auto thread = Thread::from_tid(tid);
if (!thread || thread->pid() != pid())
return ESRCH;
SpinlockLocker locker(thread->get_lock());
auto thread_name = thread->name();
if (thread_name.is_null()) {
char null_terminator = '\0';
TRY(copy_to_user(buffer, &null_terminator, sizeof(null_terminator)));
return 0;
}
if (thread_name.length() + 1 > buffer_size)
return ENAMETOOLONG;
TRY(copy_to_user(buffer, thread_name.characters_without_null_termination(), thread_name.length() + 1));
return 0;
}
ErrorOr<FlatPtr> Process::sys$gettid()
{
VERIFY_NO_PROCESS_BIG_LOCK(this)
REQUIRE_PROMISE(stdio);
return Thread::current()->tid().value();
}
}