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citra/src/core/file_sys/ncch_container.cpp

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// Copyright 2017 Citra Emulator Project
// Licensed under GPLv2 or any later version
// Refer to the license.txt file included.
#include <cinttypes>
#include <cstring>
#include <memory>
#include "common/common_types.h"
#include "common/logging/log.h"
#include "core/core.h"
#include "core/file_sys/ncch_container.h"
#include "core/loader/loader.h"
////////////////////////////////////////////////////////////////////////////////////////////////////
// FileSys namespace
namespace FileSys {
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(const 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(const u8* compressed, u32 compressed_size, u8* decompressed,
u32 decompressed_size) {
const u8* footer = compressed + compressed_size - 8;
u32 buffer_top_and_bottom = *reinterpret_cast<const 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 (unsigned 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 (unsigned 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;
}
NCCHContainer::NCCHContainer(const std::string& filepath) : filepath(filepath) {
file = FileUtil::IOFile(filepath, "rb");
}
Loader::ResultStatus NCCHContainer::OpenFile(const std::string& filepath) {
this->filepath = filepath;
file = FileUtil::IOFile(filepath, "rb");
if (!file.IsOpen()) {
LOG_WARNING(Service_FS, "Failed to open %s", filepath.c_str());
return Loader::ResultStatus::Error;
}
LOG_DEBUG(Service_FS, "Opened %s", filepath.c_str());
return Loader::ResultStatus::Success;
}
Loader::ResultStatus NCCHContainer::Load() {
if (is_loaded)
return Loader::ResultStatus::Success;
if (file.IsOpen()) {
// Reset read pointer in case this file has been read before.
file.Seek(0, SEEK_SET);
if (file.ReadBytes(&ncch_header, sizeof(NCCH_Header)) != sizeof(NCCH_Header))
return Loader::ResultStatus::Error;
// Skip NCSD header and load first NCCH (NCSD is just a container of NCCH files)...
if (Loader::MakeMagic('N', 'C', 'S', 'D') == ncch_header.magic) {
LOG_DEBUG(Service_FS, "Only loading the first (bootable) NCCH within the NCSD file!");
ncch_offset = 0x4000;
file.Seek(ncch_offset, SEEK_SET);
file.ReadBytes(&ncch_header, sizeof(NCCH_Header));
}
// Verify we are loading the correct file type...
if (Loader::MakeMagic('N', 'C', 'C', 'H') != ncch_header.magic)
return Loader::ResultStatus::ErrorInvalidFormat;
has_header = true;
// System archives and DLC don't have an extended header but have RomFS
if (ncch_header.extended_header_size) {
if (file.ReadBytes(&exheader_header, sizeof(ExHeader_Header)) !=
sizeof(ExHeader_Header))
return Loader::ResultStatus::Error;
is_compressed = (exheader_header.codeset_info.flags.flag & 1) == 1;
u32 entry_point = exheader_header.codeset_info.text.address;
u32 code_size = exheader_header.codeset_info.text.code_size;
u32 stack_size = exheader_header.codeset_info.stack_size;
u32 bss_size = exheader_header.codeset_info.bss_size;
u32 core_version = exheader_header.arm11_system_local_caps.core_version;
u8 priority = exheader_header.arm11_system_local_caps.priority;
u8 resource_limit_category =
exheader_header.arm11_system_local_caps.resource_limit_category;
LOG_DEBUG(Service_FS, "Name: %s",
exheader_header.codeset_info.name);
LOG_DEBUG(Service_FS, "Program ID: %016" PRIX64,
ncch_header.program_id);
LOG_DEBUG(Service_FS, "Code compressed: %s", is_compressed ? "yes" : "no");
LOG_DEBUG(Service_FS, "Entry point: 0x%08X", entry_point);
LOG_DEBUG(Service_FS, "Code size: 0x%08X", code_size);
LOG_DEBUG(Service_FS, "Stack size: 0x%08X", stack_size);
LOG_DEBUG(Service_FS, "Bss size: 0x%08X", bss_size);
LOG_DEBUG(Service_FS, "Core version: %d", core_version);
LOG_DEBUG(Service_FS, "Thread priority: 0x%X", priority);
LOG_DEBUG(Service_FS, "Resource limit category: %d", resource_limit_category);
LOG_DEBUG(Service_FS, "System Mode: %d",
static_cast<int>(exheader_header.arm11_system_local_caps.system_mode));
if (exheader_header.system_info.jump_id != ncch_header.program_id) {
LOG_ERROR(Service_FS,
"ExHeader Program ID mismatch: the ROM is probably encrypted.");
return Loader::ResultStatus::ErrorEncrypted;
}
has_exheader = true;
}
// DLC can have an ExeFS and a RomFS but no extended header
if (ncch_header.exefs_size) {
exefs_offset = ncch_header.exefs_offset * kBlockSize;
u32 exefs_size = ncch_header.exefs_size * kBlockSize;
LOG_DEBUG(Service_FS, "ExeFS offset: 0x%08X", exefs_offset);
LOG_DEBUG(Service_FS, "ExeFS size: 0x%08X", exefs_size);
file.Seek(exefs_offset + ncch_offset, SEEK_SET);
if (file.ReadBytes(&exefs_header, sizeof(ExeFs_Header)) != sizeof(ExeFs_Header))
return Loader::ResultStatus::Error;
exefs_file = FileUtil::IOFile(filepath, "rb");
has_exefs = true;
}
if (ncch_header.romfs_offset != 0 && ncch_header.romfs_size != 0)
has_romfs = true;
}
LoadOverrides();
// We need at least one of these or overrides, practically
if (!(has_exefs || has_romfs || is_tainted))
return Loader::ResultStatus::Error;
is_loaded = true;
return Loader::ResultStatus::Success;
}
Loader::ResultStatus NCCHContainer::LoadOverrides() {
// Check for split-off files, mark the archive as tainted if we will use them
std::string romfs_override = filepath + ".romfs";
if (FileUtil::Exists(romfs_override)) {
is_tainted = true;
}
// If we have a split-off exefs file/folder, it takes priority
std::string exefs_override = filepath + ".exefs";
std::string exefsdir_override = filepath + ".exefsdir/";
if (FileUtil::Exists(exefs_override)) {
exefs_file = FileUtil::IOFile(exefs_override, "rb");
if (exefs_file.ReadBytes(&exefs_header, sizeof(ExeFs_Header)) == sizeof(ExeFs_Header)) {
LOG_DEBUG(Service_FS, "Loading ExeFS section from %s", exefs_override.c_str());
exefs_offset = 0;
is_tainted = true;
has_exefs = true;
} else {
exefs_file = FileUtil::IOFile(filepath, "rb");
}
} else if (FileUtil::Exists(exefsdir_override) && FileUtil::IsDirectory(exefsdir_override)) {
is_tainted = true;
}
if (is_tainted)
LOG_WARNING(Service_FS,
"Loaded NCCH %s is tainted, application behavior may not be as expected!",
filepath.c_str());
return Loader::ResultStatus::Success;
}
Loader::ResultStatus NCCHContainer::LoadSectionExeFS(const char* name, std::vector<u8>& buffer) {
Loader::ResultStatus result = Load();
if (result != Loader::ResultStatus::Success)
return result;
// Check if we have files that can drop-in and replace
result = LoadOverrideExeFSSection(name, buffer);
if (result == Loader::ResultStatus::Success || !has_exefs)
return result;
// If we don't have any separate files, we'll need a full ExeFS
if (!exefs_file.IsOpen())
return Loader::ResultStatus::Error;
LOG_DEBUG(Service_FS, "%d sections:", kMaxSections);
// Iterate through the ExeFs archive until we find a section with the specified name...
for (unsigned section_number = 0; section_number < kMaxSections; section_number++) {
const auto& section = exefs_header.section[section_number];
// Load the specified section...
if (strcmp(section.name, name) == 0) {
LOG_DEBUG(Service_FS, "%d - offset: 0x%08X, size: 0x%08X, name: %s", section_number,
section.offset, section.size, section.name);
s64 section_offset =
(section.offset + exefs_offset + sizeof(ExeFs_Header) + ncch_offset);
exefs_file.Seek(section_offset, SEEK_SET);
if (strcmp(section.name, ".code") == 0 && is_compressed) {
// Section is compressed, read compressed .code section...
std::unique_ptr<u8[]> temp_buffer;
try {
temp_buffer.reset(new u8[section.size]);
} catch (std::bad_alloc&) {
return Loader::ResultStatus::ErrorMemoryAllocationFailed;
}
if (exefs_file.ReadBytes(&temp_buffer[0], section.size) != section.size)
return Loader::ResultStatus::Error;
// Decompress .code section...
u32 decompressed_size = LZSS_GetDecompressedSize(&temp_buffer[0], section.size);
buffer.resize(decompressed_size);
if (!LZSS_Decompress(&temp_buffer[0], section.size, &buffer[0], decompressed_size))
return Loader::ResultStatus::ErrorInvalidFormat;
} else {
// Section is uncompressed...
buffer.resize(section.size);
if (exefs_file.ReadBytes(&buffer[0], section.size) != section.size)
return Loader::ResultStatus::Error;
}
return Loader::ResultStatus::Success;
}
}
return Loader::ResultStatus::ErrorNotUsed;
}
Loader::ResultStatus NCCHContainer::LoadOverrideExeFSSection(const char* name,
std::vector<u8>& buffer) {
std::string override_name;
// Map our section name to the extracted equivalent
if (!strcmp(name, ".code"))
override_name = "code.bin";
else if (!strcmp(name, "icon"))
override_name = "code.bin";
else if (!strcmp(name, "banner"))
override_name = "banner.bnr";
else if (!strcmp(name, "logo"))
override_name = "logo.bcma.lz";
else
return Loader::ResultStatus::Error;
std::string section_override = filepath + ".exefsdir/" + override_name;
FileUtil::IOFile section_file(section_override, "rb");
if (section_file.IsOpen()) {
auto section_size = section_file.GetSize();
buffer.resize(section_size);
section_file.Seek(0, SEEK_SET);
if (section_file.ReadBytes(&buffer[0], section_size) == section_size) {
LOG_WARNING(Service_FS, "File %s overriding built-in ExeFS file",
section_override.c_str());
return Loader::ResultStatus::Success;
}
}
return Loader::ResultStatus::ErrorNotUsed;
}
Loader::ResultStatus NCCHContainer::ReadRomFS(std::shared_ptr<FileUtil::IOFile>& romfs_file,
u64& offset, u64& size) {
Loader::ResultStatus result = Load();
if (result != Loader::ResultStatus::Success)
return result;
if (ReadOverrideRomFS(romfs_file, offset, size) == Loader::ResultStatus::Success)
return Loader::ResultStatus::Success;
if (!has_romfs) {
LOG_DEBUG(Service_FS, "RomFS requested from NCCH which has no RomFS");
return Loader::ResultStatus::ErrorNotUsed;
}
if (!file.IsOpen())
return Loader::ResultStatus::Error;
u32 romfs_offset = ncch_offset + (ncch_header.romfs_offset * kBlockSize) + 0x1000;
u32 romfs_size = (ncch_header.romfs_size * kBlockSize) - 0x1000;
LOG_DEBUG(Service_FS, "RomFS offset: 0x%08X", romfs_offset);
LOG_DEBUG(Service_FS, "RomFS size: 0x%08X", romfs_size);
if (file.GetSize() < romfs_offset + romfs_size)
return Loader::ResultStatus::Error;
// We reopen the file, to allow its position to be independent from file's
romfs_file = std::make_shared<FileUtil::IOFile>(filepath, "rb");
if (!romfs_file->IsOpen())
return Loader::ResultStatus::Error;
offset = romfs_offset;
size = romfs_size;
return Loader::ResultStatus::Success;
}
Loader::ResultStatus NCCHContainer::ReadOverrideRomFS(std::shared_ptr<FileUtil::IOFile>& romfs_file,
u64& offset, u64& size) {
// Check for RomFS overrides
std::string split_filepath = filepath + ".romfs";
if (FileUtil::Exists(split_filepath)) {
romfs_file = std::make_shared<FileUtil::IOFile>(split_filepath, "rb");
if (romfs_file->IsOpen()) {
LOG_WARNING(Service_FS, "File %s overriding built-in RomFS", split_filepath.c_str());
offset = 0;
size = romfs_file->GetSize();
return Loader::ResultStatus::Success;
}
}
return Loader::ResultStatus::ErrorNotUsed;
}
Loader::ResultStatus NCCHContainer::ReadProgramId(u64_le& program_id) {
Loader::ResultStatus result = Load();
if (result != Loader::ResultStatus::Success)
return result;
if (!has_header)
return Loader::ResultStatus::ErrorNotUsed;
program_id = ncch_header.program_id;
return Loader::ResultStatus::Success;
}
bool NCCHContainer::HasExeFS() {
Loader::ResultStatus result = Load();
if (result != Loader::ResultStatus::Success)
return false;
return has_exefs;
}
bool NCCHContainer::HasRomFS() {
Loader::ResultStatus result = Load();
if (result != Loader::ResultStatus::Success)
return false;
return has_romfs;
}
bool NCCHContainer::HasExHeader() {
Loader::ResultStatus result = Load();
if (result != Loader::ResultStatus::Success)
return false;
return has_exheader;
}
} // namespace FileSys
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