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suyu/src/core/loader/elf.cpp
Lioncash 1b6bd9d6df kernel: Move CodeSet structure to its own source files 
Given this is utilized by the loaders, this allows avoiding inclusion of
the kernel process definitions where avoidable.

This also keeps the loading format for all executable data separate from
the kernel objects.
2019-03-20 13:07:04 -04:00

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// Copyright 2013 Dolphin Emulator Project / 2014 Citra Emulator Project
// Licensed under GPLv2 or any later version
// Refer to the license.txt file included.
#include <cstring>
#include <memory>
#include <string>
#include "common/common_funcs.h"
#include "common/common_types.h"
#include "common/file_util.h"
#include "common/logging/log.h"
#include "core/hle/kernel/code_set.h"
#include "core/hle/kernel/process.h"
#include "core/hle/kernel/vm_manager.h"
#include "core/loader/elf.h"
#include "core/memory.h"
////////////////////////////////////////////////////////////////////////////////////////////////////
// ELF Header Constants
// File type
enum ElfType {
ET_NONE = 0,
ET_REL = 1,
ET_EXEC = 2,
ET_DYN = 3,
ET_CORE = 4,
ET_LOPROC = 0xFF00,
ET_HIPROC = 0xFFFF,
};
// Machine/Architecture
enum ElfMachine {
EM_NONE = 0,
EM_M32 = 1,
EM_SPARC = 2,
EM_386 = 3,
EM_68K = 4,
EM_88K = 5,
EM_860 = 7,
EM_MIPS = 8
};
// File version
#define EV_NONE 0
#define EV_CURRENT 1
// Identification index
#define EI_MAG0 0
#define EI_MAG1 1
#define EI_MAG2 2
#define EI_MAG3 3
#define EI_CLASS 4
#define EI_DATA 5
#define EI_VERSION 6
#define EI_PAD 7
#define EI_NIDENT 16
// Sections constants
// Section types
#define SHT_NULL 0
#define SHT_PROGBITS 1
#define SHT_SYMTAB 2
#define SHT_STRTAB 3
#define SHT_RELA 4
#define SHT_HASH 5
#define SHT_DYNAMIC 6
#define SHT_NOTE 7
#define SHT_NOBITS 8
#define SHT_REL 9
#define SHT_SHLIB 10
#define SHT_DYNSYM 11
#define SHT_LOPROC 0x70000000
#define SHT_HIPROC 0x7FFFFFFF
#define SHT_LOUSER 0x80000000
#define SHT_HIUSER 0xFFFFFFFF
// Section flags
enum ElfSectionFlags {
SHF_WRITE = 0x1,
SHF_ALLOC = 0x2,
SHF_EXECINSTR = 0x4,
SHF_MASKPROC = 0xF0000000,
};
// Segment types
#define PT_NULL 0
#define PT_LOAD 1
#define PT_DYNAMIC 2
#define PT_INTERP 3
#define PT_NOTE 4
#define PT_SHLIB 5
#define PT_PHDR 6
#define PT_LOPROC 0x70000000
#define PT_HIPROC 0x7FFFFFFF
// Segment flags
#define PF_X 0x1
#define PF_W 0x2
#define PF_R 0x4
#define PF_MASKPROC 0xF0000000
typedef unsigned int Elf32_Addr;
typedef unsigned short Elf32_Half;
typedef unsigned int Elf32_Off;
typedef signed int Elf32_Sword;
typedef unsigned int Elf32_Word;
////////////////////////////////////////////////////////////////////////////////////////////////////
// ELF file header
struct Elf32_Ehdr {
unsigned char e_ident[EI_NIDENT];
Elf32_Half e_type;
Elf32_Half e_machine;
Elf32_Word e_version;
Elf32_Addr e_entry;
Elf32_Off e_phoff;
Elf32_Off e_shoff;
Elf32_Word e_flags;
Elf32_Half e_ehsize;
Elf32_Half e_phentsize;
Elf32_Half e_phnum;
Elf32_Half e_shentsize;
Elf32_Half e_shnum;
Elf32_Half e_shstrndx;
};
// Section header
struct Elf32_Shdr {
Elf32_Word sh_name;
Elf32_Word sh_type;
Elf32_Word sh_flags;
Elf32_Addr sh_addr;
Elf32_Off sh_offset;
Elf32_Word sh_size;
Elf32_Word sh_link;
Elf32_Word sh_info;
Elf32_Word sh_addralign;
Elf32_Word sh_entsize;
};
// Segment header
struct Elf32_Phdr {
Elf32_Word p_type;
Elf32_Off p_offset;
Elf32_Addr p_vaddr;
Elf32_Addr p_paddr;
Elf32_Word p_filesz;
Elf32_Word p_memsz;
Elf32_Word p_flags;
Elf32_Word p_align;
};
// Symbol table entry
struct Elf32_Sym {
Elf32_Word st_name;
Elf32_Addr st_value;
Elf32_Word st_size;
unsigned char st_info;
unsigned char st_other;
Elf32_Half st_shndx;
};
// Relocation entries
struct Elf32_Rel {
Elf32_Addr r_offset;
Elf32_Word r_info;
};
////////////////////////////////////////////////////////////////////////////////////////////////////
// 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
ElfType GetType() const {
return (ElfType)(header->e_type);
}
ElfMachine GetMachine() const {
return (ElfMachine)(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 != SHT_NOBITS)
return GetPtr(sections[section].sh_offset);
else
return nullptr;
}
bool IsCodeSection(int section) const {
return sections[section].sh_type == SHT_PROGBITS;
}
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 == SHT_NULL)
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 != ET_EXEC);
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 == PT_LOAD) {
total_image_size += (p->p_memsz + 0xFFF) & ~0xFFF;
}
}
std::vector<u8> 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 == PT_LOAD) {
Kernel::CodeSet::Segment* codeset_segment;
u32 permission_flags = p->p_flags & (PF_R | PF_W | PF_X);
if (permission_flags == (PF_R | PF_X)) {
codeset_segment = &codeset.CodeSegment();
} else if (permission_flags == (PF_R)) {
codeset_segment = &codeset.RODataSegment();
} else if (permission_flags == (PF_R | PF_W)) {
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;
memcpy(&program_image[current_image_position], GetSegmentPtr(i), p->p_filesz);
current_image_position += aligned_size;
}
}
codeset.entrypoint = base_addr + header->e_entry;
codeset.memory = std::make_shared<std::vector<u8>>(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& file) {
static constexpr u16 ELF_MACHINE_ARM{0x28};
u32 magic = 0;
if (4 != file->ReadObject(&magic))
return FileType::Error;
u16 machine = 0;
if (2 != 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;
}
ResultStatus AppLoader_ELF::Load(Kernel::Process& process) {
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.VMManager().GetCodeRegionBaseAddress();
ElfReader elf_reader(&buffer[0]);
Kernel::CodeSet codeset = elf_reader.LoadInto(base_address);
const VAddr entry_point = codeset.entrypoint;
process.LoadModule(std::move(codeset), entry_point);
process.Run(entry_point, 48, Memory::DEFAULT_STACK_SIZE);
is_loaded = true;
return ResultStatus::Success;
}
} // namespace Loader
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