ladybird/Kernel/FileSystem/InodeWatcher.h
Andreas Kling 2cb32f8356 Kernel: Let InodeWatcher track child inode numbers instead of names
First of all, this fixes a dumb info leak where we'd write kernel heap
addresses (StringImpl*) into userspace memory when reading a watcher.

Instead of trying to pass names to userspace, we now simply pass the
child inode index. Nothing in userspace makes use of this yet anyway,
so it's not like we're breaking anything. We'll see how this evolves.
2020-09-19 16:39:52 +02:00

75 lines
2.8 KiB
C++

/*
* Copyright (c) 2018-2020, Andreas Kling <kling@serenityos.org>
* All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions are met:
*
* 1. Redistributions of source code must retain the above copyright notice, this
* list of conditions and the following disclaimer.
*
* 2. Redistributions in binary form must reproduce the above copyright notice,
* this list of conditions and the following disclaimer in the documentation
* and/or other materials provided with the distribution.
*
* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
* AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
* DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE LIABLE
* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR
* SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER
* CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
* OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
* OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
*/
#pragma once
#include <AK/Badge.h>
#include <AK/CircularQueue.h>
#include <AK/WeakPtr.h>
#include <Kernel/FileSystem/File.h>
#include <Kernel/Lock.h>
namespace Kernel {
class Inode;
class InodeWatcher final : public File {
public:
static NonnullRefPtr<InodeWatcher> create(Inode&);
virtual ~InodeWatcher() override;
struct Event {
enum class Type {
Invalid = 0,
Modified,
ChildAdded,
ChildRemoved,
};
Type type { Type::Invalid };
unsigned inode_index { 0 };
};
virtual bool can_read(const FileDescription&, size_t) const override;
virtual bool can_write(const FileDescription&, size_t) const override;
virtual KResultOr<size_t> read(FileDescription&, size_t, UserOrKernelBuffer&, size_t) override;
virtual KResultOr<size_t> write(FileDescription&, size_t, const UserOrKernelBuffer&, size_t) override;
virtual String absolute_path(const FileDescription&) const override;
virtual const char* class_name() const override { return "InodeWatcher"; };
void notify_inode_event(Badge<Inode>, Event::Type);
void notify_child_added(Badge<Inode>, const InodeIdentifier& child_id);
void notify_child_removed(Badge<Inode>, const InodeIdentifier& child_id);
private:
explicit InodeWatcher(Inode&);
Lock m_lock;
WeakPtr<Inode> m_inode;
CircularQueue<Event, 32> m_queue;
};
}