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/*
* 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 <AK/StringView.h>
#include <Kernel/PerformanceManager.h>
#include <Kernel/Process.h>
#include <Kernel/VM/MemoryManager.h>
#include <Kernel/VM/PageDirectory.h>
namespace Kernel {
KResultOr<int> Process::sys$create_thread(void* (*entry)(void*), Userspace<const Syscall::SC_create_thread_params*> user_params)
{
REQUIRE_PROMISE(thread);
Syscall::SC_create_thread_params params;
if (!copy_from_user(¶ms, user_params))
return EFAULT;
unsigned detach_state = params.m_detach_state;
int schedule_priority = params.m_schedule_priority;
unsigned stack_size = params.m_stack_size;
auto user_esp = Checked<FlatPtr>((FlatPtr)params.m_stack_location);
user_esp += stack_size;
if (user_esp.has_overflow())
return EOVERFLOW;
if (!MM.validate_user_stack(*this, VirtualAddress(user_esp.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_or_error = Thread::try_create(*this);
if (thread_or_error.is_error())
return thread_or_error.error();
auto& thread = thread_or_error.value();
// We know this thread is not the main_thread,
// So give it a unique name until the user calls $set_thread_name on it
// length + 4 to give space for our extra junk at the end
StringBuilder builder(m_name.length() + 4);
thread->set_name(String::formatted("{} [{}]", m_name, thread->tid().value()));
if (!is_thread_joinable)
thread->detach();
auto& tss = thread->tss();
tss.eip = (FlatPtr)entry;
tss.eflags = 0x0202;
tss.cr3 = space().page_directory().cr3();
tss.esp = user_esp.value();
auto tsr_result = thread->make_thread_specific_region({});
if (tsr_result.is_error())
return tsr_result.error();
PerformanceManager::add_thread_created_event(*thread);
ScopedSpinLock lock(g_scheduler_lock);
thread->set_priority(requested_thread_priority);
thread->set_state(Thread::State::Runnable);
return thread->tid().value();
}
void Process::sys$exit_thread(Userspace<void*> exit_value)
{
REQUIRE_PROMISE(thread);
if (this->thread_count() == 1) {
// If this is the last thread, instead kill the process.
this->sys$exit(0);
}
auto current_thread = Thread::current();
PerformanceManager::add_thread_exit_event(*current_thread);
current_thread->exit(reinterpret_cast<void*>(exit_value.ptr()));
VERIFY_NOT_REACHED();
}
KResultOr<int> Process::sys$detach_thread(pid_t tid)
{
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;
}
KResultOr<int> Process::sys$join_thread(pid_t tid, Userspace<void**> exit_value)
{
REQUIRE_PROMISE(thread);
auto thread = Thread::from_tid(tid);
if (!thread || thread->pid() != pid())
return ESRCH;
auto current_thread = Thread::current();
if (thread == current_thread)
return EDEADLK;
void* joinee_exit_value = nullptr;
// NOTE: pthread_join() cannot be interrupted by signals. Only by death.
for (;;) {
KResult try_join_result(KSuccess);
auto result = current_thread->block<Thread::JoinBlocker>({}, *thread, try_join_result, joinee_exit_value);
if (result == Thread::BlockResult::NotBlocked) {
if (try_join_result.is_error())
return try_join_result.error();
break;
}
if (result == Thread::BlockResult::InterruptedByDeath)
break;
dbgln("join_thread: retrying");
}
if (exit_value && !copy_to_user(exit_value, &joinee_exit_value))
return EFAULT;
return 0;
}
KResultOr<int> Process::sys$set_thread_name(pid_t tid, Userspace<const char*> user_name, size_t user_name_length)
{
REQUIRE_PROMISE(stdio);
auto name = copy_string_from_user(user_name, user_name_length);
if (name.is_null())
return EFAULT;
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;
}
KResultOr<int> Process::sys$get_thread_name(pid_t tid, Userspace<char*> buffer, size_t buffer_size)
{
REQUIRE_PROMISE(thread);
if (buffer_size == 0)
return EINVAL;
auto thread = Thread::from_tid(tid);
if (!thread || thread->pid() != pid())
return ESRCH;
// We must make a temporary copy here to avoid a race with sys$set_thread_name
auto thread_name = thread->name();
if (thread_name.length() + 1 > (size_t)buffer_size)
return ENAMETOOLONG;
if (!copy_to_user(buffer, thread_name.characters(), thread_name.length() + 1))
return EFAULT;
return 0;
}
KResultOr<int> Process::sys$gettid()
{
REQUIRE_PROMISE(stdio);
return Thread::current()->tid().value();
}
}
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