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#include "RelModule.h"
#include "BlockReader.h"
#include <cstdlib>
#include <cstring>
#include <stdexcept>
extern "C" {
#include <libyaz0/yaz0.h>
}
namespace GC {
static constexpr uint32_t REL_HEADER_V1_SIZE = 0x40;
RelModule::RelModule(std::vector<uint8_t> data) : mData(std::move(data)) {
if (mData.size() < REL_HEADER_V1_SIZE) {
throw std::runtime_error("REL: file too small");
}
const uint8_t* h = mData.data();
mId = ReadBE32(h + 0x00);
const uint32_t numSections = ReadBE32(h + 0x0C);
const uint32_t sectionInfoOffset = ReadBE32(h + 0x10);
mVersion = ReadBE32(h + 0x1C);
mBssSize = ReadBE32(h + 0x20);
mRelOffset = ReadBE32(h + 0x24);
mImpOffset = ReadBE32(h + 0x28);
mImpSize = ReadBE32(h + 0x2C);
if (static_cast<uint64_t>(sectionInfoOffset) + numSections * 8ULL > mData.size()) {
throw std::runtime_error("REL: section table out of range");
}
for (uint32_t i = 0; i < numSections; i++) {
const uint8_t* s = h + sectionInfoOffset + i * 8;
const uint32_t raw = ReadBE32(s);
RelSectionInfo info = { raw & ~1u, ReadBE32(s + 4), (raw & 1) != 0 };
if (info.offset != 0 && static_cast<uint64_t>(info.offset) + info.size > mData.size()) {
throw std::runtime_error("REL: section " + std::to_string(i) + " out of range");
}
mSections.push_back(info);
}
if (static_cast<uint64_t>(mImpOffset) + mImpSize > mData.size()) {
throw std::runtime_error("REL: import table out of range");
}
for (uint32_t off = 0; off + 8 <= mImpSize; off += 8) {
mImports.push_back({ ReadBE32(h + mImpOffset + off), ReadBE32(h + mImpOffset + off + 4) });
}
}
std::vector<uint8_t> RelModule::Decompress(const std::vector<uint8_t>& data) {
if (data.size() < 16 || std::memcmp(data.data(), "Yaz0", 4) != 0) {
return data;
}
uint32_t size = 0;
uint8_t* decoded = yaz0_decode(data.data(), &size);
if (decoded == nullptr) {
throw std::runtime_error("Failed to decode Yaz0");
}
std::vector<uint8_t> out(decoded, decoded + size);
free(decoded);
return out;
}
std::vector<RelRelocation> RelModule::GetRelocations(const RelImport& imp) const {
std::vector<RelRelocation> out;
for (uint64_t off = imp.offset; off + 8 <= mData.size(); off += 8) {
const uint8_t* r = mData.data() + off;
RelRelocation rel = { ReadBE16(r), r[2], r[3], ReadBE32(r + 4) };
out.push_back(rel);
if (rel.type == R_DOLPHIN_END) {
return out;
}
}
throw std::runtime_error("REL: relocation list without R_DOLPHIN_END");
}
std::vector<std::string> RelModule::GetSectionNames() const {
static const char* standard[] = { "", ".text", ".ctors", ".dtors", ".rodata", ".data", ".bss" };
std::vector<std::string> names(mSections.size());
const bool isStandard = mSections.size() == 7 && mSections[1].exec && !mSections[6].exec &&
(mSections[6].IsBss() || mSections[6].size == 0);
if (isStandard) {
for (size_t i = 0; i < names.size(); i++) {
names[i] = standard[i];
}
return names;
}
std::vector<size_t> data;
int texts = 0;
for (size_t i = 0; i < mSections.size(); i++) {
const auto& s = mSections[i];
if (s.offset == 0 && s.size == 0) {
continue;
}
if (s.IsBss()) {
names[i] = ".bss";
} else if (s.exec) {
names[i] = texts++ == 0 ? ".text" : ".text" + std::to_string(texts - 1);
} else {
data.push_back(i);
}
}
static const char* dataNames[] = { ".ctors", ".dtors", ".rodata", ".data" };
for (size_t j = 0; j < data.size(); j++) {
names[data[j]] = data.size() == 4 ? dataNames[j] : ".data" + std::to_string(j);
}
return names;
}
std::optional<uint32_t> RelModule::FindSection(const std::string& name) const {
const auto names = GetSectionNames();
for (size_t i = 0; i < names.size(); i++) {
if (names[i] == name) {
return static_cast<uint32_t>(i);
}
}
char* end = nullptr;
const unsigned long index = std::strtoul(name.c_str(), &end, 0);
if (!name.empty() && end != nullptr && *end == '\0' && index < mSections.size()) {
return static_cast<uint32_t>(index);
}
return std::nullopt;
}
std::vector<std::vector<uint8_t>> RelModule::GetSectionData() const {
std::vector<std::vector<uint8_t>> out;
for (const auto& s : mSections) {
if (s.offset == 0) {
out.emplace_back(s.size, 0);
} else {
out.emplace_back(mData.begin() + s.offset, mData.begin() + s.offset + s.size);
}
}
return out;
}
RelLinkStats RelModule::Link(const std::vector<std::optional<uint32_t>>& bases,
std::vector<std::vector<uint8_t>>& sections) const {
RelLinkStats stats;
for (const auto& imp : this->mImports) {
const bool self = imp.moduleId == this->mId;
if (!self && imp.moduleId != 0) {
for (const auto& rel : GetRelocations(imp)) {
if (rel.type < R_DOLPHIN_NOP) {
stats.unknownModule++;
}
}
continue;
}
std::optional<uint32_t> section;
uint32_t cursor = 0;
for (const auto& rel : GetRelocations(imp)) {
cursor += rel.offset;
if (rel.type == R_DOLPHIN_END) {
break;
}
if (rel.type == R_DOLPHIN_NOP) {
continue;
}
if (rel.type == R_DOLPHIN_SECTION) {
section = rel.section;
cursor = 0;
continue;
}
if (rel.type == R_PPC_NONE) {
continue;
}
if (!section.has_value() || section.value() >= sections.size() || section.value() >= bases.size() ||
!bases[section.value()].has_value()) {
stats.skippedUnplaced++;
continue;
}
uint32_t offset = 0;
if (self) {
if (rel.section >= bases.size() || !bases[rel.section].has_value()) {
stats.unresolvedTarget++;
stats.unresolved.push_back({ section.value(), cursor, rel.type, rel.section, rel.addend });
continue;
}
offset = bases[rel.section].value();
}
auto& data = sections[section.value()];
const uint32_t width = rel.type == R_PPC_ADDR32 || rel.type == R_PPC_ADDR24 ||
rel.type == R_PPC_REL24 || rel.type == R_PPC_ADDR14 ||
rel.type == R_PPC_ADDR14_BRTAKEN || rel.type == R_PPC_ADDR14_BRNTAKEN ||
rel.type == R_PPC_REL14 || rel.type == R_PPC_REL14_BRTAKEN ||
rel.type == R_PPC_REL14_BRNTAKEN
? 4
: 2;
if (static_cast<uint64_t>(cursor) + width > data.size()) {
throw std::runtime_error("REL: relocation writes past the end of section " +
std::to_string(section.value()));
}
uint8_t* p = data.data() + cursor;
const uint32_t where = bases[section.value()].value() + cursor;
const uint32_t x = offset + rel.addend;
switch (rel.type) {
case R_PPC_ADDR32:
WriteBE32(p, x);
break;
case R_PPC_ADDR24:
WriteBE32(p, (ReadBE32(p) & ~0x03FFFFFCu) | (x & 0x03FFFFFCu));
break;
case R_PPC_ADDR16:
case R_PPC_ADDR16_LO:
WriteBE16(p, x & 0xFFFF);
break;
case R_PPC_ADDR16_HI:
WriteBE16(p, (x >> 16) & 0xFFFF);
break;
case R_PPC_ADDR16_HA:
WriteBE16(p, ((x >> 16) + ((x & 0x8000) ? 1 : 0)) & 0xFFFF);
break;
case R_PPC_REL24:
WriteBE32(p, (ReadBE32(p) & ~0x03FFFFFCu) | ((x - where) & 0x03FFFFFCu));
break;
case R_PPC_ADDR14:
case R_PPC_ADDR14_BRTAKEN:
case R_PPC_ADDR14_BRNTAKEN:
WriteBE32(p, (ReadBE32(p) & ~0xFFFCu) | (x & 0xFFFCu));
break;
case R_PPC_REL14:
case R_PPC_REL14_BRTAKEN:
case R_PPC_REL14_BRNTAKEN:
WriteBE32(p, (ReadBE32(p) & ~0xFFFCu) | ((x - where) & 0xFFFCu));
break;
default:
stats.unknownType++;
continue;
}
stats.applied++;
stats.byType[rel.type]++;
}
}
return stats;
}
} // namespace GC
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