mirror of
https://github.com/SerenityOS/serenity
synced 2024-09-06 17:06:31 +00:00
e8aff0c1c8
This commit updates the lock function from Spinlock and RecursiveSpinlock to return the InterruptsState of the processor, instead of the processor flags. The unlock functions would only look at the interrupt flag of the processor flags, so we now use the InterruptsState enum to clarify the intent, and such that we can use the same Spinlock code for the aarch64 build. To not break the build, all the call sites are updated aswell.
859 lines
27 KiB
C++
859 lines
27 KiB
C++
/*
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* Copyright (c) 2020, the SerenityOS developers.
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* Copyright (c) 2022, Idan Horowitz <idan.horowitz@serenityos.org>
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*
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* SPDX-License-Identifier: BSD-2-Clause
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*/
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#include <AK/BuiltinWrappers.h>
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#include <Kernel/Debug.h>
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#include <Kernel/FileSystem/OpenFileDescription.h>
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#include <Kernel/Net/Socket.h>
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#include <Kernel/Process.h>
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#include <Kernel/Scheduler.h>
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#include <Kernel/Thread.h>
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namespace Kernel {
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Thread::BlockTimeout::BlockTimeout(bool is_absolute, Time const* time, Time const* start_time, clockid_t clock_id)
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: m_clock_id(clock_id)
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, m_infinite(!time)
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{
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if (m_infinite)
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return;
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if (*time > Time::zero())
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m_time = *time;
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m_start_time = start_time ? *start_time : TimeManagement::the().current_time(clock_id);
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if (!is_absolute)
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m_time += m_start_time;
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}
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bool Thread::Blocker::add_to_blocker_set(Thread::BlockerSet& blocker_set, void* data)
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{
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VERIFY(!m_blocker_set);
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if (blocker_set.add_blocker(*this, data)) {
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m_blocker_set = &blocker_set;
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return true;
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}
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return false;
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}
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Thread::Blocker::~Blocker() = default;
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void Thread::Blocker::finalize()
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{
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if (m_blocker_set)
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m_blocker_set->remove_blocker(*this);
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}
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bool Thread::Blocker::setup_blocker()
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{
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return true;
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}
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void Thread::Blocker::begin_blocking(Badge<Thread>)
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{
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SpinlockLocker lock(m_lock);
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VERIFY(!m_is_blocking);
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m_is_blocking = true;
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}
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auto Thread::Blocker::end_blocking(Badge<Thread>, bool did_timeout) -> BlockResult
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{
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SpinlockLocker lock(m_lock);
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// if m_is_blocking is false here, some thread forced to
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// unblock us when we get here. This is only called from the
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// thread that was blocked.
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VERIFY(Thread::current() == m_thread);
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m_is_blocking = false;
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was_unblocked(did_timeout);
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return block_result();
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}
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Thread::JoinBlocker::JoinBlocker(Thread& joinee, ErrorOr<void>& try_join_result, void*& joinee_exit_value)
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: m_joinee(joinee)
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, m_joinee_exit_value(joinee_exit_value)
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, m_try_join_result(try_join_result)
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{
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}
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bool Thread::JoinBlocker::setup_blocker()
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{
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// We need to hold our lock to avoid a race where try_join succeeds
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// but the joinee is joining immediately
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SpinlockLocker lock(m_lock);
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bool should_block = true;
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m_try_join_result = m_joinee->try_join([&]() {
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if (!add_to_blocker_set(m_joinee->m_join_blocker_set))
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should_block = false;
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});
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if (m_try_join_result.is_error())
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return false;
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return should_block;
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}
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void Thread::JoinBlocker::will_unblock_immediately_without_blocking(UnblockImmediatelyReason reason)
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{
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// If we should have blocked but got here it must have been that the
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// timeout was already in the past. So we need to ask the BlockerSet
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// to supply us the information. We cannot hold the lock as unblock
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// could be called by the BlockerSet at any time!
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if (reason == UnblockImmediatelyReason::TimeoutInThePast) {
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m_joinee->m_join_blocker_set.try_unblock(*this);
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}
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}
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bool Thread::JoinBlocker::unblock(void* value, bool from_add_blocker)
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{
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{
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SpinlockLocker lock(m_lock);
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if (m_did_unblock)
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return false;
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m_did_unblock = true;
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m_joinee_exit_value = value;
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do_set_interrupted_by_death();
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}
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if (!from_add_blocker)
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unblock_from_blocker();
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return true;
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}
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Thread::WaitQueueBlocker::WaitQueueBlocker(WaitQueue& wait_queue, StringView block_reason)
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: m_wait_queue(wait_queue)
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, m_block_reason(block_reason)
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{
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}
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bool Thread::WaitQueueBlocker::setup_blocker()
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{
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return add_to_blocker_set(m_wait_queue);
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}
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Thread::WaitQueueBlocker::~WaitQueueBlocker() = default;
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bool Thread::WaitQueueBlocker::unblock()
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{
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{
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SpinlockLocker lock(m_lock);
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if (m_did_unblock)
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return false;
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m_did_unblock = true;
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}
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unblock_from_blocker();
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return true;
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}
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Thread::FutexBlocker::FutexBlocker(FutexQueue& futex_queue, u32 bitset)
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: m_futex_queue(futex_queue)
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, m_bitset(bitset)
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{
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}
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bool Thread::FutexBlocker::setup_blocker()
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{
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return add_to_blocker_set(m_futex_queue);
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}
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Thread::FutexBlocker::~FutexBlocker() = default;
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void Thread::FutexBlocker::finish_requeue(FutexQueue& futex_queue)
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{
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VERIFY(m_lock.is_locked_by_current_processor());
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set_blocker_set_raw_locked(&futex_queue);
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// We can now release the lock
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m_lock.unlock(m_previous_interrupts_state);
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}
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bool Thread::FutexBlocker::unblock_bitset(u32 bitset)
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{
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{
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SpinlockLocker lock(m_lock);
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if (m_did_unblock || (bitset != FUTEX_BITSET_MATCH_ANY && (m_bitset & bitset) == 0))
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return false;
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m_did_unblock = true;
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}
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unblock_from_blocker();
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return true;
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}
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bool Thread::FutexBlocker::unblock(bool force)
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{
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{
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SpinlockLocker lock(m_lock);
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if (m_did_unblock)
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return force;
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m_did_unblock = true;
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}
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unblock_from_blocker();
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return true;
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}
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Thread::OpenFileDescriptionBlocker::OpenFileDescriptionBlocker(OpenFileDescription& description, BlockFlags flags, BlockFlags& unblocked_flags)
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: m_blocked_description(description)
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, m_flags(flags)
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, m_unblocked_flags(unblocked_flags)
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{
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}
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bool Thread::OpenFileDescriptionBlocker::setup_blocker()
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{
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m_unblocked_flags = BlockFlags::None;
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return add_to_blocker_set(m_blocked_description->blocker_set());
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}
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bool Thread::OpenFileDescriptionBlocker::unblock_if_conditions_are_met(bool from_add_blocker, void*)
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{
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auto unblock_flags = m_blocked_description->should_unblock(m_flags);
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if (unblock_flags == BlockFlags::None)
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return false;
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{
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SpinlockLocker lock(m_lock);
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if (m_did_unblock)
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return false;
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m_did_unblock = true;
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m_unblocked_flags = unblock_flags;
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}
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if (!from_add_blocker)
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unblock_from_blocker();
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return true;
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}
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void Thread::OpenFileDescriptionBlocker::will_unblock_immediately_without_blocking(UnblockImmediatelyReason reason)
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{
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if (reason == UnblockImmediatelyReason::UnblockConditionAlreadyMet)
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return;
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// If we should have blocked but got here it must have been that the
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// timeout was already in the past. So we need to ask the BlockerSet
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// to supply us the information. We cannot hold the lock as unblock
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// could be called by the BlockerSet at any time!
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VERIFY(reason == UnblockImmediatelyReason::TimeoutInThePast);
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// Just call unblock_if_conditions_are_met here because we will query the file description
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// for the data and don't need any input from the FileBlockerSet.
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// However, it's possible that if timeout_in_past is true then FileBlockerSet
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// may call us at any given time, so our call to unblock here may fail.
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// Either way, unblock will be called at least once, which provides
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// all the data we need.
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unblock_if_conditions_are_met(false, nullptr);
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}
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OpenFileDescription const& Thread::OpenFileDescriptionBlocker::blocked_description() const
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{
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return m_blocked_description;
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}
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Thread::AcceptBlocker::AcceptBlocker(OpenFileDescription& description, BlockFlags& unblocked_flags)
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: OpenFileDescriptionBlocker(description, BlockFlags::Accept | BlockFlags::Exception, unblocked_flags)
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{
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}
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Thread::ConnectBlocker::ConnectBlocker(OpenFileDescription& description, BlockFlags& unblocked_flags)
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: OpenFileDescriptionBlocker(description, BlockFlags::Connect | BlockFlags::Exception, unblocked_flags)
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{
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}
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Thread::WriteBlocker::WriteBlocker(OpenFileDescription& description, BlockFlags& unblocked_flags)
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: OpenFileDescriptionBlocker(description, BlockFlags::Write | BlockFlags::Exception, unblocked_flags)
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{
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}
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auto Thread::WriteBlocker::override_timeout(BlockTimeout const& timeout) -> BlockTimeout const&
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{
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auto const& description = blocked_description();
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if (description.is_socket()) {
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auto const& socket = *description.socket();
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if (socket.has_send_timeout()) {
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Time send_timeout = socket.send_timeout();
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m_timeout = BlockTimeout(false, &send_timeout, timeout.start_time(), timeout.clock_id());
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if (timeout.is_infinite() || (!m_timeout.is_infinite() && m_timeout.absolute_time() < timeout.absolute_time()))
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return m_timeout;
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}
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}
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return timeout;
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}
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Thread::ReadBlocker::ReadBlocker(OpenFileDescription& description, BlockFlags& unblocked_flags)
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: OpenFileDescriptionBlocker(description, BlockFlags::Read | BlockFlags::Exception, unblocked_flags)
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{
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}
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auto Thread::ReadBlocker::override_timeout(BlockTimeout const& timeout) -> BlockTimeout const&
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{
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auto const& description = blocked_description();
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if (description.is_socket()) {
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auto const& socket = *description.socket();
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if (socket.has_receive_timeout()) {
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Time receive_timeout = socket.receive_timeout();
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m_timeout = BlockTimeout(false, &receive_timeout, timeout.start_time(), timeout.clock_id());
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if (timeout.is_infinite() || (!m_timeout.is_infinite() && m_timeout.absolute_time() < timeout.absolute_time()))
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return m_timeout;
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}
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}
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return timeout;
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}
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Thread::SleepBlocker::SleepBlocker(BlockTimeout const& deadline, Time* remaining)
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: m_deadline(deadline)
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, m_remaining(remaining)
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{
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}
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auto Thread::SleepBlocker::override_timeout(BlockTimeout const& timeout) -> BlockTimeout const&
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{
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VERIFY(timeout.is_infinite()); // A timeout should not be provided
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// To simplify things only use the sleep deadline.
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return m_deadline;
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}
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void Thread::SleepBlocker::will_unblock_immediately_without_blocking(UnblockImmediatelyReason reason)
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{
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// SleepBlocker::should_block should always return true, so timeout
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// in the past is the only valid case when this function is called
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VERIFY(reason == UnblockImmediatelyReason::TimeoutInThePast);
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calculate_remaining();
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}
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void Thread::SleepBlocker::was_unblocked(bool did_timeout)
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{
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Blocker::was_unblocked(did_timeout);
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calculate_remaining();
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}
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void Thread::SleepBlocker::calculate_remaining()
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{
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if (!m_remaining)
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return;
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auto time_now = TimeManagement::the().current_time(m_deadline.clock_id());
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if (time_now < m_deadline.absolute_time())
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*m_remaining = m_deadline.absolute_time() - time_now;
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else
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*m_remaining = {};
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}
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Thread::BlockResult Thread::SleepBlocker::block_result()
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{
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auto result = Blocker::block_result();
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if (result == Thread::BlockResult::InterruptedByTimeout)
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return Thread::BlockResult::WokeNormally;
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return result;
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}
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Thread::SelectBlocker::SelectBlocker(FDVector& fds)
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: m_fds(fds)
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{
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}
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bool Thread::SelectBlocker::setup_blocker()
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{
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bool should_block = true;
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for (auto& fd_entry : m_fds) {
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fd_entry.unblocked_flags = FileBlocker::BlockFlags::None;
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if (!should_block)
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continue;
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if (!fd_entry.description) {
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should_block = false;
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continue;
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}
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if (!fd_entry.description->blocker_set().add_blocker(*this, &fd_entry))
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should_block = false;
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}
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return should_block;
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}
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Thread::SelectBlocker::~SelectBlocker() = default;
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void Thread::SelectBlocker::finalize()
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{
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Thread::FileBlocker::finalize();
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for (auto& fd_entry : m_fds) {
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if (fd_entry.description)
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fd_entry.description->blocker_set().remove_blocker(*this);
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}
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}
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void Thread::SelectBlocker::will_unblock_immediately_without_blocking(UnblockImmediatelyReason reason)
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{
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SpinlockLocker lock(m_lock);
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if (m_did_unblock)
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return;
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m_did_unblock = true;
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if (reason == UnblockImmediatelyReason::UnblockConditionAlreadyMet) {
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auto count = collect_unblocked_flags();
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VERIFY(count > 0);
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}
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}
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bool Thread::SelectBlocker::unblock_if_conditions_are_met(bool from_add_blocker, void* data)
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{
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VERIFY(data); // data is a pointer to an entry in the m_fds vector
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auto& fd_info = *static_cast<FDInfo*>(data);
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{
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SpinlockLocker lock(m_lock);
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if (m_did_unblock)
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return false;
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VERIFY(fd_info.description);
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auto unblock_flags = fd_info.description->should_unblock(fd_info.block_flags);
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if (unblock_flags == BlockFlags::None)
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return false;
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m_did_unblock = true;
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// We need to store unblock_flags here, otherwise someone else
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// affecting this file descriptor could change the information
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// between now and when was_unblocked is called!
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fd_info.unblocked_flags = unblock_flags;
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}
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// Only do this once for the first one
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if (!from_add_blocker)
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unblock_from_blocker();
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return true;
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}
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size_t Thread::SelectBlocker::collect_unblocked_flags()
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{
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size_t count = 0;
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for (auto& fd_entry : m_fds) {
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VERIFY(fd_entry.block_flags != FileBlocker::BlockFlags::None);
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if (!fd_entry.description) {
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count++;
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continue;
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}
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// unblock will have set at least the first descriptor's unblock
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// flags that triggered the unblock. Make sure we don't discard that
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// information as it may have changed by now!
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if (fd_entry.unblocked_flags == FileBlocker::BlockFlags::None)
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fd_entry.unblocked_flags = fd_entry.description->should_unblock(fd_entry.block_flags);
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if (fd_entry.unblocked_flags != FileBlocker::BlockFlags::None)
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count++;
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}
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return count;
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}
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void Thread::SelectBlocker::was_unblocked(bool did_timeout)
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{
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Blocker::was_unblocked(did_timeout);
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if (!did_timeout && !was_interrupted()) {
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{
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SpinlockLocker lock(m_lock);
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VERIFY(m_did_unblock);
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}
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size_t count = collect_unblocked_flags();
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// If we were blocked and didn't time out, we should have at least one unblocked fd!
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VERIFY(count > 0);
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}
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}
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Thread::SignalBlocker::SignalBlocker(sigset_t pending_set, siginfo_t& result)
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: m_pending_set(pending_set)
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, m_result(result)
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{
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}
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void Thread::SignalBlocker::will_unblock_immediately_without_blocking(UnblockImmediatelyReason unblock_immediately_reason)
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{
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if (unblock_immediately_reason != UnblockImmediatelyReason::TimeoutInThePast)
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return;
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// If the specified timeout is 0 the caller is simply trying to poll once for pending signals,
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// so simply calling check_pending_signals should populate the requested information.
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check_pending_signals(false);
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}
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bool Thread::SignalBlocker::setup_blocker()
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{
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return add_to_blocker_set(thread().m_signal_blocker_set);
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}
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bool Thread::SignalBlocker::check_pending_signals(bool from_add_blocker)
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{
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{
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SpinlockLocker lock(m_lock);
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if (m_did_unblock)
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return false;
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auto pending_signals = thread().pending_signals() & m_pending_set;
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// Also unblock if we have just "handled" that signal and are in the procecss
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// of running their signal handler (i.e. we just unmarked the signal as pending).
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if (thread().m_currently_handled_signal)
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pending_signals |= (1 << (thread().m_currently_handled_signal - 1)) & m_pending_set;
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auto matching_pending_signal = bit_scan_forward(pending_signals);
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if (matching_pending_signal == 0)
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return false;
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m_did_unblock = true;
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m_result = {};
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m_result.si_signo = matching_pending_signal;
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m_result.si_code = 0; // FIXME: How can we determine this?
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}
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if (!from_add_blocker)
|
|
unblock_from_blocker();
|
|
return true;
|
|
}
|
|
|
|
Thread::WaitBlockerSet::ProcessBlockInfo::ProcessBlockInfo(NonnullLockRefPtr<Process>&& process, WaitBlocker::UnblockFlags flags, u8 signal)
|
|
: process(move(process))
|
|
, flags(flags)
|
|
, signal(signal)
|
|
{
|
|
}
|
|
|
|
Thread::WaitBlockerSet::ProcessBlockInfo::~ProcessBlockInfo() = default;
|
|
|
|
void Thread::WaitBlockerSet::try_unblock(Thread::WaitBlocker& blocker)
|
|
{
|
|
SpinlockLocker lock(m_lock);
|
|
// We if we have any processes pending
|
|
for (size_t i = 0; i < m_processes.size(); i++) {
|
|
auto& info = m_processes[i];
|
|
// We need to call unblock as if we were called from add_blocker
|
|
// so that we don't trigger a context switch by yielding!
|
|
if (info.was_waited && blocker.is_wait())
|
|
continue; // This state was already waited on, do not unblock
|
|
if (blocker.unblock(info.process, info.flags, info.signal, true)) {
|
|
if (blocker.is_wait()) {
|
|
if (info.flags == Thread::WaitBlocker::UnblockFlags::Terminated) {
|
|
m_processes.remove(i);
|
|
dbgln_if(WAITBLOCK_DEBUG, "WaitBlockerSet[{}] terminated, remove {}", m_process, *info.process);
|
|
} else {
|
|
dbgln_if(WAITBLOCK_DEBUG, "WaitBlockerSet[{}] terminated, mark as waited {}", m_process, *info.process);
|
|
info.was_waited = true;
|
|
}
|
|
}
|
|
break;
|
|
}
|
|
}
|
|
}
|
|
|
|
void Thread::WaitBlockerSet::disowned_by_waiter(Process& process)
|
|
{
|
|
SpinlockLocker lock(m_lock);
|
|
if (m_finalized)
|
|
return;
|
|
for (size_t i = 0; i < m_processes.size();) {
|
|
auto& info = m_processes[i];
|
|
if (info.process == &process) {
|
|
unblock_all_blockers_whose_conditions_are_met_locked([&](Blocker& b, void*, bool&) {
|
|
VERIFY(b.blocker_type() == Blocker::Type::Wait);
|
|
auto& blocker = static_cast<WaitBlocker&>(b);
|
|
bool did_unblock = blocker.unblock(info.process, WaitBlocker::UnblockFlags::Disowned, 0, false);
|
|
VERIFY(did_unblock); // disowning must unblock everyone
|
|
return true;
|
|
});
|
|
dbgln_if(WAITBLOCK_DEBUG, "WaitBlockerSet[{}] disowned {}", m_process, *info.process);
|
|
m_processes.remove(i);
|
|
continue;
|
|
}
|
|
|
|
i++;
|
|
}
|
|
}
|
|
|
|
bool Thread::WaitBlockerSet::unblock(Process& process, WaitBlocker::UnblockFlags flags, u8 signal)
|
|
{
|
|
VERIFY(flags != WaitBlocker::UnblockFlags::Disowned);
|
|
|
|
bool did_unblock_any = false;
|
|
bool did_wait = false;
|
|
bool was_waited_already = false;
|
|
|
|
SpinlockLocker lock(m_lock);
|
|
if (m_finalized)
|
|
return false;
|
|
if (flags != WaitBlocker::UnblockFlags::Terminated) {
|
|
// First check if this state was already waited on
|
|
for (auto& info : m_processes) {
|
|
if (info.process == &process) {
|
|
was_waited_already = info.was_waited;
|
|
break;
|
|
}
|
|
}
|
|
}
|
|
|
|
unblock_all_blockers_whose_conditions_are_met_locked([&](Blocker& b, void*, bool&) {
|
|
VERIFY(b.blocker_type() == Blocker::Type::Wait);
|
|
auto& blocker = static_cast<WaitBlocker&>(b);
|
|
if (was_waited_already && blocker.is_wait())
|
|
return false; // This state was already waited on, do not unblock
|
|
if (blocker.unblock(process, flags, signal, false)) {
|
|
did_wait |= blocker.is_wait(); // anyone requesting a wait
|
|
did_unblock_any = true;
|
|
return true;
|
|
}
|
|
return false;
|
|
});
|
|
|
|
// If no one has waited (yet), or this wasn't a wait, or if it's anything other than
|
|
// UnblockFlags::Terminated then add it to your list
|
|
if (!did_unblock_any || !did_wait || flags != WaitBlocker::UnblockFlags::Terminated) {
|
|
bool updated_existing = false;
|
|
for (auto& info : m_processes) {
|
|
if (info.process == &process) {
|
|
VERIFY(info.flags != WaitBlocker::UnblockFlags::Terminated);
|
|
info.flags = flags;
|
|
info.signal = signal;
|
|
info.was_waited = did_wait;
|
|
dbgln_if(WAITBLOCK_DEBUG, "WaitBlockerSet[{}] update {} flags={}, waited={}", m_process, process, (int)flags, info.was_waited);
|
|
updated_existing = true;
|
|
break;
|
|
}
|
|
}
|
|
if (!updated_existing) {
|
|
dbgln_if(WAITBLOCK_DEBUG, "WaitBlockerSet[{}] add {} flags: {}", m_process, process, (int)flags);
|
|
m_processes.append(ProcessBlockInfo(process, flags, signal));
|
|
}
|
|
}
|
|
return did_unblock_any;
|
|
}
|
|
|
|
bool Thread::WaitBlockerSet::should_add_blocker(Blocker& b, void*)
|
|
{
|
|
// NOTE: m_lock is held already!
|
|
if (m_finalized)
|
|
return false;
|
|
VERIFY(b.blocker_type() == Blocker::Type::Wait);
|
|
auto& blocker = static_cast<WaitBlocker&>(b);
|
|
// See if we can match any process immediately
|
|
for (size_t i = 0; i < m_processes.size(); i++) {
|
|
auto& info = m_processes[i];
|
|
if (blocker.unblock(info.process, info.flags, info.signal, true)) {
|
|
// Only remove the entry if UnblockFlags::Terminated
|
|
if (info.flags == Thread::WaitBlocker::UnblockFlags::Terminated && blocker.is_wait())
|
|
m_processes.remove(i);
|
|
return false;
|
|
}
|
|
}
|
|
return true;
|
|
}
|
|
|
|
void Thread::WaitBlockerSet::finalize()
|
|
{
|
|
SpinlockLocker lock(m_lock);
|
|
VERIFY(!m_finalized);
|
|
m_finalized = true;
|
|
|
|
// Clear the list of threads here so we can drop the references to them
|
|
m_processes.clear();
|
|
|
|
// NOTE: Kernel processes don't have a leaked ref on them.
|
|
if (!m_process.is_kernel_process()) {
|
|
// No more waiters, drop the last reference immediately. This may
|
|
// cause us to be destructed ourselves!
|
|
VERIFY(m_process.ref_count() > 0);
|
|
m_process.unref();
|
|
}
|
|
}
|
|
|
|
Thread::WaitBlocker::WaitBlocker(int wait_options, Variant<Empty, NonnullLockRefPtr<Process>, NonnullLockRefPtr<ProcessGroup>> waitee, ErrorOr<siginfo_t>& result)
|
|
: m_wait_options(wait_options)
|
|
, m_result(result)
|
|
, m_waitee(move(waitee))
|
|
{
|
|
}
|
|
|
|
bool Thread::WaitBlocker::setup_blocker()
|
|
{
|
|
if (m_wait_options & WNOHANG)
|
|
return false;
|
|
return add_to_blocker_set(Process::current().wait_blocker_set());
|
|
}
|
|
|
|
void Thread::WaitBlocker::will_unblock_immediately_without_blocking(UnblockImmediatelyReason)
|
|
{
|
|
Process::current().wait_blocker_set().try_unblock(*this);
|
|
}
|
|
|
|
void Thread::WaitBlocker::was_unblocked(bool)
|
|
{
|
|
bool got_sigchld, try_unblock;
|
|
{
|
|
SpinlockLocker lock(m_lock);
|
|
try_unblock = !m_did_unblock;
|
|
got_sigchld = m_got_sigchild;
|
|
}
|
|
|
|
if (try_unblock)
|
|
Process::current().wait_blocker_set().try_unblock(*this);
|
|
|
|
// If we were interrupted by SIGCHLD (which gets special handling
|
|
// here) we're not going to return with EINTR. But we're going to
|
|
// deliver SIGCHLD (only) here.
|
|
auto* current_thread = Thread::current();
|
|
if (got_sigchld && current_thread->state() != State::Stopped)
|
|
current_thread->try_dispatch_one_pending_signal(SIGCHLD);
|
|
}
|
|
|
|
void Thread::WaitBlocker::do_was_disowned()
|
|
{
|
|
VERIFY(!m_did_unblock);
|
|
m_did_unblock = true;
|
|
m_result = ECHILD;
|
|
}
|
|
|
|
void Thread::WaitBlocker::do_set_result(siginfo_t const& result)
|
|
{
|
|
VERIFY(!m_did_unblock);
|
|
m_did_unblock = true;
|
|
m_result = result;
|
|
|
|
if (do_get_interrupted_by_signal() == SIGCHLD) {
|
|
// This makes it so that wait() will return normally despite the
|
|
// fact that SIGCHLD was delivered. Calling do_clear_interrupted_by_signal
|
|
// will disable dispatching signals in Thread::block and prevent
|
|
// it from returning with EINTR. We will then manually dispatch
|
|
// SIGCHLD (and only SIGCHLD) in was_unblocked.
|
|
m_got_sigchild = true;
|
|
do_clear_interrupted_by_signal();
|
|
}
|
|
}
|
|
|
|
bool Thread::WaitBlocker::unblock(Process& process, UnblockFlags flags, u8 signal, bool from_add_blocker)
|
|
{
|
|
VERIFY(flags != UnblockFlags::Terminated || signal == 0); // signal argument should be ignored for Terminated
|
|
|
|
bool do_not_unblock = m_waitee.visit(
|
|
[&](NonnullLockRefPtr<Process> const& waitee_process) {
|
|
return &process != waitee_process;
|
|
},
|
|
[&](NonnullLockRefPtr<ProcessGroup> const& waitee_process_group) {
|
|
return waitee_process_group->pgid() != process.pgid();
|
|
},
|
|
[&](Empty const&) {
|
|
// Generic waiter won't be unblocked by disown
|
|
return flags == UnblockFlags::Disowned;
|
|
});
|
|
|
|
if (do_not_unblock)
|
|
return false;
|
|
|
|
switch (flags) {
|
|
case UnblockFlags::Terminated:
|
|
if (!(m_wait_options & WEXITED))
|
|
return false;
|
|
break;
|
|
case UnblockFlags::Stopped:
|
|
if (!(m_wait_options & WSTOPPED))
|
|
return false;
|
|
if (!(m_wait_options & WUNTRACED) && !process.is_traced())
|
|
return false;
|
|
break;
|
|
case UnblockFlags::Continued:
|
|
if (!(m_wait_options & WCONTINUED))
|
|
return false;
|
|
if (!(m_wait_options & WUNTRACED) && !process.is_traced())
|
|
return false;
|
|
break;
|
|
case UnblockFlags::Disowned:
|
|
SpinlockLocker lock(m_lock);
|
|
// Disowning must unblock anyone waiting for this process explicitly
|
|
if (!m_did_unblock)
|
|
do_was_disowned();
|
|
return true;
|
|
}
|
|
|
|
if (flags == UnblockFlags::Terminated) {
|
|
VERIFY(process.is_dead());
|
|
|
|
SpinlockLocker lock(m_lock);
|
|
if (m_did_unblock)
|
|
return false;
|
|
// Up until this point, this function may have been called
|
|
// more than once!
|
|
do_set_result(process.wait_info());
|
|
} else {
|
|
siginfo_t siginfo {};
|
|
{
|
|
SpinlockLocker lock(g_scheduler_lock);
|
|
auto credentials = process.credentials();
|
|
// We need to gather the information before we release the scheduler lock!
|
|
siginfo.si_signo = SIGCHLD;
|
|
siginfo.si_pid = process.pid().value();
|
|
siginfo.si_uid = credentials->uid().value();
|
|
siginfo.si_status = signal;
|
|
|
|
switch (flags) {
|
|
case UnblockFlags::Terminated:
|
|
case UnblockFlags::Disowned:
|
|
VERIFY_NOT_REACHED();
|
|
case UnblockFlags::Stopped:
|
|
siginfo.si_code = CLD_STOPPED;
|
|
break;
|
|
case UnblockFlags::Continued:
|
|
siginfo.si_code = CLD_CONTINUED;
|
|
break;
|
|
}
|
|
}
|
|
|
|
SpinlockLocker lock(m_lock);
|
|
if (m_did_unblock)
|
|
return false;
|
|
// Up until this point, this function may have been called
|
|
// more than once!
|
|
do_set_result(siginfo);
|
|
}
|
|
|
|
if (!from_add_blocker) {
|
|
// Only call unblock if we weren't called from within add_to_blocker_set!
|
|
VERIFY(flags != UnblockFlags::Disowned);
|
|
unblock_from_blocker();
|
|
}
|
|
// Because this may be called from add_blocker, in which case we should
|
|
// not be actually trying to unblock the thread (because it hasn't actually
|
|
// been blocked yet), we need to return true anyway
|
|
return true;
|
|
}
|
|
|
|
Thread::FlockBlocker::FlockBlocker(NonnullLockRefPtr<Inode> inode, flock const& flock)
|
|
: m_inode(move(inode))
|
|
, m_flock(flock)
|
|
{
|
|
}
|
|
|
|
void Thread::FlockBlocker::will_unblock_immediately_without_blocking(UnblockImmediatelyReason reason)
|
|
{
|
|
VERIFY(reason == UnblockImmediatelyReason::UnblockConditionAlreadyMet);
|
|
}
|
|
|
|
bool Thread::FlockBlocker::setup_blocker()
|
|
{
|
|
return add_to_blocker_set(m_inode->flock_blocker_set());
|
|
}
|
|
|
|
bool Thread::FlockBlocker::try_unblock(bool from_add_blocker)
|
|
{
|
|
if (!m_inode->can_apply_flock(m_flock))
|
|
return false;
|
|
|
|
{
|
|
SpinlockLocker lock(m_lock);
|
|
if (m_did_unblock)
|
|
return false;
|
|
m_did_unblock = true;
|
|
}
|
|
|
|
if (!from_add_blocker)
|
|
unblock_from_blocker();
|
|
return true;
|
|
}
|
|
|
|
}
|