skyline/app/src/main/cpp/skyline/kernel/types/KSharedMemory.h

// SPDX-License-Identifier: MPL-2.0
// Copyright © 2020 Skyline Team and Contributors (https://github.com/skyline-emu/)

#pragma once

#include "KMemory.h"

namespace skyline::kernel::type {
    /**
     * @brief KSharedMemory is used to retain two mappings of the same underlying memory, allowing sharing memory between two processes
     */
    class KSharedMemory : public KMemory {
      private:
        int fd; //!< A file descriptor to the underlying shared memory

      public:
        span<u8> host; //!< We also keep a host mirror of the underlying shared memory for host access, it is persistently mapped and should be used by anything accessing the memory on the host

        KSharedMemory(const DeviceState &state, size_t size, KType type = KType::KSharedMemory);

        /**
         * @note 'ptr' needs to be in guest-reserved address space
         */
        u8 *Map(span<u8> map, memory::Permission permission);

        /**
         * @note 'ptr' needs to be in guest-reserved address space
         */
        void Unmap(span<u8> map);

        /**
         * @brief The destructor of shared memory, it deallocates the memory from all processes
         */
        ~KSharedMemory();
    };
}