Files
eden/src/core/loader/nso.h
T
PavelBARABANOV 815325ccec [loader] add ZBIC (zstd variant) NSO decompression support for Switch 22.0+ (#4482)
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-------------------
A new NSO compression method was introduced in Switch 22.0.0. This is a
customized variant of zstd and is used when NSO flags have bit 7 set.

Key characteristics:
  - ZSTD_MAGICNUMBER is set to 0x4349425A (b'ZBIC') instead of 0xFD2FB528
  - ZSTD_LEGACY_SUPPORT is set to 0
  - ZSTD_TRACE is set to 1, zstd version used is 1.5.7 (10507)
  - FSE_readNCount is replaced with a BIC (Binary Interpolative Coding)
    version which improves compression of entropy tables significantly

Source: https://switchbrew.org/wiki/22.0.0

Implementation:
  - Detect ZBIC segments via NSO flag bit 7 (NsoFlags_UseZbicCompression)
    and/or ZBIC magic scan in nso.cpp
  - Fall back to LZ4 when ZBIC is not detected or returns unexpected size
  - Handle segment 0 alternate offset (0x100 vs 0x108) for both ZBIC and LZ4

References:
  - Atmosphère loader/strat zstd-zbic integration:
    https://github.com/Atmosphere-NX/Atmosphere/commit/082115187a0509cb6b8a757de639a4e4741b8712
  - nxdumptool ZBIC segment compression support:
    https://github.com/DarkMatterCore/nxdumptool/commit/441e5c0904f29427987433be4eb057a2843d222a
  - STORM_SWITCH ZBIC implementation:
    https://github.com/ReiKatari/STORM_SWITCH/commit/1e09eb82b760aaf340b810031400991c0740c091

Tested with firmware 23.0.0 and ZBIC-compressed NSOs.

Co-authored-by: xbzk <xbzk@eden-emu.dev>
Reviewed-on: https://git.eden-emu.dev/eden-emu/eden/pulls/4482
Reviewed-by: CamilleLaVey <camillelavey99@gmail.com>
Reviewed-by: lizzie <lizzie@eden-emu.dev>
Reviewed-by: Maufeat <sahyno1996@gmail.com>
2026-09-27 12:48:45 +02:00

114 lines
3.2 KiB
C++

// SPDX-FileCopyrightText: Copyright 2026 Eden Emulator Project
// SPDX-License-Identifier: GPL-3.0-or-later
// SPDX-FileCopyrightText: Copyright 2018 yuzu Emulator Project
// SPDX-License-Identifier: GPL-2.0-or-later
#pragma once
#include <array>
#include <optional>
#include <type_traits>
#include "common/common_types.h"
#include "common/swap.h"
#include "core/file_sys/patch_manager.h"
#include "core/loader/loader.h"
namespace Core {
class System;
}
namespace Core::NCE {
class Patcher;
}
namespace Kernel {
class KProcess;
}
namespace Loader {
struct NSOSegmentHeader {
u32_le offset;
u32_le location;
u32_le size;
union {
u32_le alignment;
u32_le bss_size;
};
};
static_assert(sizeof(NSOSegmentHeader) == 0x10, "NsoSegmentHeader has incorrect size.");
struct NSOHeader {
using SHA256Hash = std::array<u8, 0x20>;
struct RODataRelativeExtent {
u32_le data_offset;
u32_le size;
};
u32_le magic;
u32_le version;
u32 reserved;
u32_le flags;
std::array<NSOSegmentHeader, 3> segments; // Text, RoData, Data (in that order)
std::array<u8, 0x20> build_id;
std::array<u32_le, 3> segments_compressed_size;
std::array<u8, 0x1C> padding;
RODataRelativeExtent api_info_extent;
RODataRelativeExtent dynstr_extent;
RODataRelativeExtent dynsyn_extent;
std::array<SHA256Hash, 3> segment_hashes;
bool IsSegmentCompressed(size_t segment_num) const;
bool IsZBICCompressed() const {
return ((flags >> 7) & 1) != 0;
}
};
static_assert(sizeof(NSOHeader) == 0x100, "NSOHeader has incorrect size.");
static_assert(std::is_trivially_copyable_v<NSOHeader>, "NSOHeader must be trivially copyable.");
constexpr u32 NSO_ARGUMENT_DATA_ALLOCATION_SIZE = 0x9000;
struct NSOArgumentHeader {
u32_le allocated_size;
u32_le actual_size;
INSERT_PADDING_BYTES(0x18);
};
static_assert(sizeof(NSOArgumentHeader) == 0x20, "NSOArgumentHeader has incorrect size.");
/// Loads an NSO file
class AppLoader_NSO final : public AppLoader {
public:
explicit AppLoader_NSO(FileSys::VirtualFile file_);
/**
* Identifies whether or not the given file is a form of NSO file.
*
* @param in_file The file to be identified.
*
* @return FileType::NSO if found, or FileType::Error if some other type of file.
*/
static FileType IdentifyType(const FileSys::VirtualFile& in_file);
FileType GetFileType() const override {
return IdentifyType(file);
}
static std::optional<VAddr> LoadModule(Kernel::KProcess& process, Core::System& system,
const FileSys::VfsFile& nso_file, VAddr load_base,
bool should_pass_arguments, bool load_into_process,
std::optional<FileSys::PatchManager> pm = {},
std::vector<Core::NCE::Patcher>* patches = nullptr,
s32 patch_index = -1);
LoadResult Load(Kernel::KProcess& process, Core::System& system) override;
ResultStatus ReadNSOModules(Modules& out_modules) override;
private:
Modules modules;
};
} // namespace Loader