mirror of
https://github.com/RGBCube/serenity
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3e30d9bc99
This closes two race windows: - ProcessGroup removed itself from the "all process groups" list in its destructor. It was possible to walk the list between the last unref() and the destructor invocation, and grab a pointer to a ProcessGroup that was about to get deleted. - sys$setsid() could end up creating a process group that already existed, as there was a race window between checking if the PGID is used, and actually creating a ProcessGroup with that PGID.
59 lines
1.8 KiB
C++
59 lines
1.8 KiB
C++
/*
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* Copyright (c) 2020, the SerenityOS developers.
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* Copyright (c) 2021-2023, Andreas Kling <kling@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/Singleton.h>
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#include <Kernel/ProcessGroup.h>
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namespace Kernel {
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static Singleton<SpinlockProtected<ProcessGroup::AllInstancesList, LockRank::None>> s_all_instances;
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SpinlockProtected<ProcessGroup::AllInstancesList, LockRank::None>& ProcessGroup::all_instances()
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{
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return s_all_instances;
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}
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ProcessGroup::~ProcessGroup() = default;
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ErrorOr<NonnullRefPtr<ProcessGroup>> ProcessGroup::create_if_unused_pgid(ProcessGroupID pgid)
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{
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return all_instances().with([&](auto& all_instances) -> ErrorOr<NonnullRefPtr<ProcessGroup>> {
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for (auto& process_group : all_instances) {
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if (process_group.pgid() == pgid)
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return EPERM;
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}
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auto process_group = TRY(adopt_nonnull_ref_or_enomem(new (nothrow) ProcessGroup(pgid)));
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all_instances.prepend(*process_group);
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return process_group;
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});
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}
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ErrorOr<NonnullRefPtr<ProcessGroup>> ProcessGroup::find_or_create(ProcessGroupID pgid)
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{
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return all_instances().with([&](auto& all_instances) -> ErrorOr<NonnullRefPtr<ProcessGroup>> {
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for (auto& group : all_instances) {
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if (group.pgid() == pgid)
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return group;
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}
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auto process_group = TRY(adopt_nonnull_ref_or_enomem(new (nothrow) ProcessGroup(pgid)));
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all_instances.prepend(*process_group);
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return process_group;
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});
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}
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RefPtr<ProcessGroup> ProcessGroup::from_pgid(ProcessGroupID pgid)
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{
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return all_instances().with([&](auto& groups) -> RefPtr<ProcessGroup> {
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for (auto& group : groups) {
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if (group.pgid() == pgid)
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return &group;
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}
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return nullptr;
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});
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}
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}
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