serenity/AK/SharedBuffer.cpp

/*
 * 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.
 */

#include <AK/SharedBuffer.h>
#include <AK/kmalloc.h>
#include <Kernel/Syscall.h>
#include <stdio.h>
#include <unistd.h>

namespace AK {

RefPtr<SharedBuffer> SharedBuffer::create_with_size(int size)
{
    void* data;
    int shared_buffer_id = create_shared_buffer(size, &data);
    if (shared_buffer_id < 0) {
        perror("create_shared_buffer");
        return nullptr;
    }
    return adopt(*new SharedBuffer(shared_buffer_id, size, data));
}

bool SharedBuffer::share_with(pid_t peer)
{
    int ret = share_buffer_with(shared_buffer_id(), peer);
    if (ret < 0) {
        perror("share_buffer_with");
        return false;
    }
    return true;
}

bool SharedBuffer::share_globally()
{
    int ret = share_buffer_globally(shared_buffer_id());
    if (ret < 0) {
        perror("share_buffer_globally");
        return false;
    }
    return true;
}

RefPtr<SharedBuffer> SharedBuffer::create_from_shared_buffer_id(int shared_buffer_id)
{
    void* data = get_shared_buffer(shared_buffer_id);
    if (data == (void*)-1) {
        perror("get_shared_buffer");
        return nullptr;
    }
    int size = get_shared_buffer_size(shared_buffer_id);
    if (size < 0) {
        perror("get_shared_buffer_size");
        return nullptr;
    }
    return adopt(*new SharedBuffer(shared_buffer_id, size, data));
}

SharedBuffer::SharedBuffer(int shared_buffer_id, int size, void* data)
    : m_shared_buffer_id(shared_buffer_id)
    , m_size(size)
    , m_data(data)
{
}

SharedBuffer::~SharedBuffer()
{
    if (m_shared_buffer_id >= 0) {
        int rc = release_shared_buffer(m_shared_buffer_id);
        if (rc < 0) {
            perror("release_shared_buffer");
        }
    }
}

void SharedBuffer::seal()
{
    int rc = seal_shared_buffer(m_shared_buffer_id);
    if (rc < 0) {
        perror("seal_shared_buffer");
        ASSERT_NOT_REACHED();
    }
}

void SharedBuffer::set_volatile()
{
    u32 rc = syscall(SC_set_shared_buffer_volatile, m_shared_buffer_id, true);
    ASSERT(rc == 0);
}

bool SharedBuffer::set_nonvolatile()
{
    u32 rc = syscall(SC_set_shared_buffer_volatile, m_shared_buffer_id, false);
    if (rc == 0)
        return true;
    if (rc == 1)
        return false;
    ASSERT_NOT_REACHED();
}

}