citra-shitamoto-network/src/core/loader/ncch.cpp

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// Copyright 2014 Citra Emulator Project
2014-12-17 11:08:14 +05:30
// Licensed under GPLv2 or any later version
// Refer to the license.txt file included.
#include <memory>
#include "core/loader/ncch.h"
#include "core/hle/kernel/kernel.h"
#include "core/mem_map.h"
////////////////////////////////////////////////////////////////////////////////////////////////////
// Loader namespace
namespace Loader {
static const int kMaxSections = 8; ///< Maximum number of sections (files) in an ExeFs
static const int kBlockSize = 0x200; ///< Size of ExeFS blocks (in bytes)
/**
* Get the decompressed size of an LZSS compressed ExeFS file
* @param buffer Buffer of compressed file
* @param size Size of compressed buffer
* @return Size of decompressed buffer
*/
static u32 LZSS_GetDecompressedSize(u8* buffer, u32 size) {
u32 offset_size = *(u32*)(buffer + size - 4);
return offset_size + size;
}
/**
* Decompress ExeFS file (compressed with LZSS)
* @param compressed Compressed buffer
* @param compressed_size Size of compressed buffer
* @param decompressed Decompressed buffer
* @param decompressed_size Size of decompressed buffer
* @return True on success, otherwise false
*/
static bool LZSS_Decompress(u8* compressed, u32 compressed_size, u8* decompressed, u32 decompressed_size) {
u8* footer = compressed + compressed_size - 8;
u32 buffer_top_and_bottom = *(u32*)footer;
u32 out = decompressed_size;
u32 index = compressed_size - ((buffer_top_and_bottom >> 24) & 0xFF);
u32 stop_index = compressed_size - (buffer_top_and_bottom & 0xFFFFFF);
memset(decompressed, 0, decompressed_size);
memcpy(decompressed, compressed, compressed_size);
while(index > stop_index) {
u8 control = compressed[--index];
for(u32 i = 0; i < 8; i++) {
if(index <= stop_index)
break;
if(index <= 0)
break;
if(out <= 0)
break;
if(control & 0x80) {
// Check if compression is out of bounds
if(index < 2) {
return false;
}
index -= 2;
u32 segment_offset = compressed[index] | (compressed[index + 1] << 8);
u32 segment_size = ((segment_offset >> 12) & 15) + 3;
segment_offset &= 0x0FFF;
segment_offset += 2;
// Check if compression is out of bounds
if(out < segment_size) {
return false;
}
for(u32 j = 0; j < segment_size; j++) {
// Check if compression is out of bounds
if(out + segment_offset >= decompressed_size) {
return false;
}
u8 data = decompressed[out + segment_offset];
decompressed[--out] = data;
}
} else {
// Check if compression is out of bounds
if(out < 1) {
return false;
}
decompressed[--out] = compressed[--index];
}
control <<= 1;
}
}
return true;
}
////////////////////////////////////////////////////////////////////////////////////////////////////
// AppLoader_NCCH class
ResultStatus AppLoader_NCCH::LoadExec() const {
if (!is_loaded)
return ResultStatus::ErrorNotLoaded;
std::vector<u8> code;
if (ResultStatus::Success == ReadCode(code)) {
Memory::WriteBlock(entry_point, &code[0], code.size());
Kernel::LoadExec(entry_point);
return ResultStatus::Success;
}
return ResultStatus::Error;
}
ResultStatus AppLoader_NCCH::LoadSectionExeFS(const char* name, std::vector<u8>& buffer) const {
// Iterate through the ExeFs archive until we find the .code file...
if (!file->IsOpen())
return ResultStatus::Error;
LOG_DEBUG(Loader, "%d sections:", kMaxSections);
for (int i = 0; i < kMaxSections; i++) {
// Load the specified section...
if (strcmp((const char*)exefs_header.section[i].name, name) == 0) {
LOG_DEBUG(Loader, "%d - offset: 0x%08X, size: 0x%08X, name: %s", i,
exefs_header.section[i].offset, exefs_header.section[i].size,
exefs_header.section[i].name);
s64 section_offset = (exefs_header.section[i].offset + exefs_offset +
sizeof(ExeFs_Header)+ncch_offset);
file->Seek(section_offset, 0);
// Section is compressed...
if (i == 0 && is_compressed) {
// Read compressed .code section...
std::unique_ptr<u8[]> temp_buffer;
try {
temp_buffer.reset(new u8[exefs_header.section[i].size]);
} catch (std::bad_alloc&) {
return ResultStatus::ErrorMemoryAllocationFailed;
}
file->ReadBytes(&temp_buffer[0], exefs_header.section[i].size);
// Decompress .code section...
u32 decompressed_size = LZSS_GetDecompressedSize(&temp_buffer[0],
exefs_header.section[i].size);
buffer.resize(decompressed_size);
if (!LZSS_Decompress(&temp_buffer[0], exefs_header.section[i].size, &buffer[0],
decompressed_size)) {
return ResultStatus::ErrorInvalidFormat;
}
// Section is uncompressed...
}
else {
buffer.resize(exefs_header.section[i].size);
file->ReadBytes(&buffer[0], exefs_header.section[i].size);
}
return ResultStatus::Success;
}
}
return ResultStatus::ErrorNotUsed;
}
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ResultStatus AppLoader_NCCH::Load() {
if (is_loaded)
return ResultStatus::ErrorAlreadyLoaded;
if (!file->IsOpen())
return ResultStatus::Error;
file->ReadBytes(&ncch_header, sizeof(NCCH_Header));
// Skip NCSD header and load first NCCH (NCSD is just a container of NCCH files)...
if (0 == memcmp(&ncch_header.magic, "NCSD", 4)) {
LOG_WARNING(Loader, "Only loading the first (bootable) NCCH within the NCSD file!");
ncch_offset = 0x4000;
file->Seek(ncch_offset, 0);
file->ReadBytes(&ncch_header, sizeof(NCCH_Header));
}
// Verify we are loading the correct file type...
if (0 != memcmp(&ncch_header.magic, "NCCH", 4))
return ResultStatus::ErrorInvalidFormat;
// Read ExHeader...
file->ReadBytes(&exheader_header, sizeof(ExHeader_Header));
is_compressed = (exheader_header.codeset_info.flags.flag & 1) == 1;
entry_point = exheader_header.codeset_info.text.address;
LOG_INFO(Loader, "Name: %s", exheader_header.codeset_info.name);
LOG_DEBUG(Loader, "Code compressed: %s", is_compressed ? "yes" : "no");
LOG_DEBUG(Loader, "Entry point: 0x%08X", entry_point);
// Read ExeFS...
exefs_offset = ncch_header.exefs_offset * kBlockSize;
u32 exefs_size = ncch_header.exefs_size * kBlockSize;
LOG_DEBUG(Loader, "ExeFS offset: 0x%08X", exefs_offset);
LOG_DEBUG(Loader, "ExeFS size: 0x%08X", exefs_size);
file->Seek(exefs_offset + ncch_offset, 0);
file->ReadBytes(&exefs_header, sizeof(ExeFs_Header));
LoadExec(); // Load the executable into memory for booting
is_loaded = true; // Set state to loaded
return ResultStatus::Success;
}
ResultStatus AppLoader_NCCH::ReadCode(std::vector<u8>& buffer) const {
return LoadSectionExeFS(".code", buffer);
}
ResultStatus AppLoader_NCCH::ReadIcon(std::vector<u8>& buffer) const {
return LoadSectionExeFS("icon", buffer);
}
ResultStatus AppLoader_NCCH::ReadBanner(std::vector<u8>& buffer) const {
return LoadSectionExeFS("banner", buffer);
}
ResultStatus AppLoader_NCCH::ReadLogo(std::vector<u8>& buffer) const {
return LoadSectionExeFS("logo", buffer);
}
ResultStatus AppLoader_NCCH::ReadRomFS(std::vector<u8>& buffer) const {
if (!file->IsOpen())
return ResultStatus::Error;
// Check if the NCCH has a RomFS...
if (ncch_header.romfs_offset != 0 && ncch_header.romfs_size != 0) {
u32 romfs_offset = ncch_offset + (ncch_header.romfs_offset * kBlockSize) + 0x1000;
u32 romfs_size = (ncch_header.romfs_size * kBlockSize) - 0x1000;
LOG_DEBUG(Loader, "RomFS offset: 0x%08X", romfs_offset);
LOG_DEBUG(Loader, "RomFS size: 0x%08X", romfs_size);
buffer.resize(romfs_size);
file->Seek(romfs_offset, 0);
file->ReadBytes(&buffer[0], romfs_size);
return ResultStatus::Success;
}
LOG_DEBUG(Loader, "NCCH has no RomFS");
return ResultStatus::ErrorNotUsed;
}
u64 AppLoader_NCCH::GetProgramId() const {
return *reinterpret_cast<u64 const*>(&ncch_header.program_id[0]);
}
} // namespace Loader