ladybird/Kernel/Syscalls/alarm.cpp
Brian Gianforcaro 9201a06027 Kernel: Annotate all syscalls with VERIFY_PROCESS_BIG_LOCK_ACQUIRED
Before we start disabling acquisition of the big process lock for
specific syscalls, make sure to document and assert that all the
lock is held during all syscalls.
2021-07-20 03:21:14 +02:00

46 lines
1.5 KiB
C++

/*
* Copyright (c) 2018-2020, Andreas Kling <kling@serenityos.org>
*
* SPDX-License-Identifier: BSD-2-Clause
*/
#include <Kernel/Process.h>
#include <Kernel/Time/TimeManagement.h>
namespace Kernel {
KResultOr<FlatPtr> Process::sys$alarm(unsigned seconds)
{
VERIFY_PROCESS_BIG_LOCK_ACQUIRED(this);
REQUIRE_PROMISE(stdio);
unsigned previous_alarm_remaining = 0;
if (m_alarm_timer) {
if (TimerQueue::the().cancel_timer(*m_alarm_timer)) {
// The timer hasn't fired. Round up the remaining time (if any)
Time remaining = m_alarm_timer->remaining() + Time::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 (previous_alarm_remaining == 0)
previous_alarm_remaining = 1;
}
if (seconds > 0) {
auto deadline = TimeManagement::the().current_time(CLOCK_REALTIME_COARSE);
deadline = deadline + Time::from_seconds(seconds);
if (!m_alarm_timer) {
m_alarm_timer = adopt_ref_if_nonnull(new (nothrow) Timer());
if (!m_alarm_timer)
return ENOMEM;
}
auto timer_was_added = TimerQueue::the().add_timer_without_id(*m_alarm_timer, CLOCK_REALTIME_COARSE, deadline, [this]() {
[[maybe_unused]] auto rc = send_signal(SIGALRM, nullptr);
});
if (!timer_was_added)
return ENOMEM;
}
return previous_alarm_remaining;
}
}