ladybird/Kernel/Syscalls/alarm.cpp

48 lines
1.7 KiB
C++

/*
* Copyright (c) 2018-2020, Andreas Kling <kling@serenityos.org>
*
* SPDX-License-Identifier: BSD-2-Clause
*/
#include <Kernel/Tasks/Process.h>
#include <Kernel/Time/TimeManagement.h>
#include <Kernel/Time/TimerQueue.h>
namespace Kernel {
ErrorOr<FlatPtr> Process::sys$alarm(unsigned seconds)
{
VERIFY_NO_PROCESS_BIG_LOCK(this);
TRY(require_promise(Pledge::stdio));
return m_alarm_timer.with([&](auto& timer) -> ErrorOr<FlatPtr> {
unsigned previous_alarm_remaining = 0;
if (timer) {
bool was_in_use = false;
if (TimerQueue::the().cancel_timer(*timer, &was_in_use)) {
// The timer hasn't fired. Round up the remaining time (if any)
Duration remaining = timer->remaining() + Duration::from_nanoseconds(999'999'999);
previous_alarm_remaining = remaining.to_truncated_seconds();
}
// We had an existing alarm, must return a non-zero value here!
if (was_in_use && previous_alarm_remaining == 0)
previous_alarm_remaining = 1;
}
if (seconds > 0) {
auto deadline = TimeManagement::the().current_time(CLOCK_REALTIME_COARSE);
deadline = deadline + Duration::from_seconds(seconds);
if (!timer) {
timer = TRY(adopt_nonnull_ref_or_enomem(new (nothrow) Timer));
}
auto timer_was_added = TimerQueue::the().add_timer_without_id(*timer, CLOCK_REALTIME_COARSE, deadline, [this]() {
MUST(send_signal(SIGALRM, nullptr));
});
if (!timer_was_added)
return ENOMEM;
}
return previous_alarm_remaining;
});
}
}