yuzu-android/src/core/loader/elf.cpp

264 lines
7.8 KiB
C++

// SPDX-FileCopyrightText: 2013 Dolphin Emulator Project
// SPDX-FileCopyrightText: 2014 Citra Emulator Project
// SPDX-License-Identifier: GPL-2.0-or-later
#include <cstring>
#include <memory>
#include "common/common_funcs.h"
#include "common/common_types.h"
#include "common/elf.h"
#include "common/logging/log.h"
#include "core/hle/kernel/code_set.h"
#include "core/hle/kernel/k_page_table.h"
#include "core/hle/kernel/k_process.h"
#include "core/loader/elf.h"
#include "core/memory.h"
using namespace Common::ELF;
////////////////////////////////////////////////////////////////////////////////////////////////////
// ElfReader class
typedef int SectionID;
class ElfReader {
private:
char* base;
u32* base32;
Elf32_Ehdr* header;
Elf32_Phdr* segments;
Elf32_Shdr* sections;
u32* sectionAddrs;
bool relocate;
VAddr entryPoint;
public:
explicit ElfReader(void* ptr);
u32 Read32(int off) const {
return base32[off >> 2];
}
// Quick accessors
u16 GetType() const {
return header->e_type;
}
u16 GetMachine() const {
return header->e_machine;
}
VAddr GetEntryPoint() const {
return entryPoint;
}
u32 GetFlags() const {
return (u32)(header->e_flags);
}
Kernel::CodeSet LoadInto(VAddr vaddr);
int GetNumSegments() const {
return (int)(header->e_phnum);
}
int GetNumSections() const {
return (int)(header->e_shnum);
}
const u8* GetPtr(int offset) const {
return (u8*)base + offset;
}
const char* GetSectionName(int section) const;
const u8* GetSectionDataPtr(int section) const {
if (section < 0 || section >= header->e_shnum)
return nullptr;
if (sections[section].sh_type != ElfShtNobits)
return GetPtr(sections[section].sh_offset);
else
return nullptr;
}
bool IsCodeSection(int section) const {
return sections[section].sh_type == ElfShtProgBits;
}
const u8* GetSegmentPtr(int segment) {
return GetPtr(segments[segment].p_offset);
}
u32 GetSectionAddr(SectionID section) const {
return sectionAddrs[section];
}
unsigned int GetSectionSize(SectionID section) const {
return sections[section].sh_size;
}
SectionID GetSectionByName(const char* name, int firstSection = 0) const; //-1 for not found
bool DidRelocate() const {
return relocate;
}
};
ElfReader::ElfReader(void* ptr) {
base = (char*)ptr;
base32 = (u32*)ptr;
header = (Elf32_Ehdr*)ptr;
segments = (Elf32_Phdr*)(base + header->e_phoff);
sections = (Elf32_Shdr*)(base + header->e_shoff);
entryPoint = header->e_entry;
}
const char* ElfReader::GetSectionName(int section) const {
if (sections[section].sh_type == ElfShtNull)
return nullptr;
int name_offset = sections[section].sh_name;
const char* ptr = reinterpret_cast<const char*>(GetSectionDataPtr(header->e_shstrndx));
if (ptr)
return ptr + name_offset;
return nullptr;
}
Kernel::CodeSet ElfReader::LoadInto(VAddr vaddr) {
LOG_DEBUG(Loader, "String section: {}", header->e_shstrndx);
// Should we relocate?
relocate = (header->e_type != ElfTypeExec);
if (relocate) {
LOG_DEBUG(Loader, "Relocatable module");
entryPoint += vaddr;
} else {
LOG_DEBUG(Loader, "Prerelocated executable");
}
LOG_DEBUG(Loader, "{} segments:", header->e_phnum);
// First pass : Get the bits into RAM
const VAddr base_addr = relocate ? vaddr : 0;
u64 total_image_size = 0;
for (unsigned int i = 0; i < header->e_phnum; ++i) {
const Elf32_Phdr* p = &segments[i];
if (p->p_type == ElfPtLoad) {
total_image_size += (p->p_memsz + 0xFFF) & ~0xFFF;
}
}
Kernel::PhysicalMemory program_image(total_image_size);
std::size_t current_image_position = 0;
Kernel::CodeSet codeset;
for (unsigned int i = 0; i < header->e_phnum; ++i) {
const Elf32_Phdr* p = &segments[i];
LOG_DEBUG(Loader, "Type: {} Vaddr: {:08X} Filesz: {:08X} Memsz: {:08X} ", p->p_type,
p->p_vaddr, p->p_filesz, p->p_memsz);
if (p->p_type == ElfPtLoad) {
Kernel::CodeSet::Segment* codeset_segment;
u32 permission_flags = p->p_flags & (ElfPfRead | ElfPfWrite | ElfPfExec);
if (permission_flags == (ElfPfRead | ElfPfExec)) {
codeset_segment = &codeset.CodeSegment();
} else if (permission_flags == (ElfPfRead)) {
codeset_segment = &codeset.RODataSegment();
} else if (permission_flags == (ElfPfRead | ElfPfWrite)) {
codeset_segment = &codeset.DataSegment();
} else {
LOG_ERROR(Loader, "Unexpected ELF PT_LOAD segment id {} with flags {:X}", i,
p->p_flags);
continue;
}
if (codeset_segment->size != 0) {
LOG_ERROR(Loader,
"ELF has more than one segment of the same type. Skipping extra "
"segment (id {})",
i);
continue;
}
const VAddr segment_addr = base_addr + p->p_vaddr;
const u32 aligned_size = (p->p_memsz + 0xFFF) & ~0xFFF;
codeset_segment->offset = current_image_position;
codeset_segment->addr = segment_addr;
codeset_segment->size = aligned_size;
std::memcpy(program_image.data() + current_image_position, GetSegmentPtr(i),
p->p_filesz);
current_image_position += aligned_size;
}
}
codeset.entrypoint = base_addr + header->e_entry;
codeset.memory = std::move(program_image);
LOG_DEBUG(Loader, "Done loading.");
return codeset;
}
SectionID ElfReader::GetSectionByName(const char* name, int firstSection) const {
for (int i = firstSection; i < header->e_shnum; i++) {
const char* secname = GetSectionName(i);
if (secname != nullptr && strcmp(name, secname) == 0)
return i;
}
return -1;
}
////////////////////////////////////////////////////////////////////////////////////////////////////
// Loader namespace
namespace Loader {
AppLoader_ELF::AppLoader_ELF(FileSys::VirtualFile file_) : AppLoader(std::move(file_)) {}
FileType AppLoader_ELF::IdentifyType(const FileSys::VirtualFile& elf_file) {
static constexpr u16 ELF_MACHINE_ARM{0x28};
u32 magic = 0;
if (4 != elf_file->ReadObject(&magic)) {
return FileType::Error;
}
u16 machine = 0;
if (2 != elf_file->ReadObject(&machine, 18)) {
return FileType::Error;
}
if (Common::MakeMagic('\x7f', 'E', 'L', 'F') == magic && ELF_MACHINE_ARM == machine) {
return FileType::ELF;
}
return FileType::Error;
}
AppLoader_ELF::LoadResult AppLoader_ELF::Load(Kernel::KProcess& process,
[[maybe_unused]] Core::System& system) {
if (is_loaded) {
return {ResultStatus::ErrorAlreadyLoaded, {}};
}
std::vector<u8> buffer = file->ReadAllBytes();
if (buffer.size() != file->GetSize()) {
return {ResultStatus::ErrorIncorrectELFFileSize, {}};
}
const VAddr base_address = process.PageTable().GetCodeRegionStart();
ElfReader elf_reader(&buffer[0]);
Kernel::CodeSet codeset = elf_reader.LoadInto(base_address);
const VAddr entry_point = codeset.entrypoint;
// Setup the process code layout
if (process.LoadFromMetadata(FileSys::ProgramMetadata::GetDefault(), buffer.size()).IsError()) {
return {ResultStatus::ErrorNotInitialized, {}};
}
process.LoadModule(std::move(codeset), entry_point);
is_loaded = true;
return {ResultStatus::Success, LoadParameters{48, Core::Memory::DEFAULT_STACK_SIZE}};
}
} // namespace Loader