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suyu/src/core/loader/elf.cpp

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// Copyright 2013 Dolphin Emulator Project
// Licensed under GPLv2
// Refer to the license.txt file included.
#include <string>
#include <memory>
#include "common/common.h"
#include "common/file_util.h"
#include "common/symbols.h"
#include "core/mem_map.h"
#include "core/loader/elf.h"
#include "core/hle/kernel/kernel.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
// Magic number
#define ELFMAG0 0x7F
#define ELFMAG1 'E'
#define ELFMAG2 'L'
#define ELFMAG3 'F'
// 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
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;
u32 entryPoint;
public:
ElfReader(void *ptr);
~ElfReader() { }
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); }
u32 GetEntryPoint() const { return entryPoint; }
u32 GetFlags() const { return (u32)(header->e_flags); }
bool LoadInto(u32 vaddr);
bool LoadSymbols();
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]; }
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() {
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;
LoadSymbols();
}
const char *ElfReader::GetSectionName(int section) const {
if (sections[section].sh_type == SHT_NULL)
return nullptr;
int name_offset = sections[section].sh_name;
char *ptr = (char*)GetSectionDataPtr(header->e_shstrndx);
if (ptr)
return ptr + name_offset;
return nullptr;
}
bool ElfReader::LoadInto(u32 vaddr) {
DEBUG_LOG(MASTER_LOG, "String section: %i", header->e_shstrndx);
// Should we relocate?
relocate = (header->e_type != ET_EXEC);
if (relocate) {
DEBUG_LOG(MASTER_LOG, "Relocatable module");
entryPoint += vaddr;
} else {
DEBUG_LOG(MASTER_LOG, "Prerelocated executable");
}
INFO_LOG(MASTER_LOG, "%i segments:", header->e_phnum);
// First pass : Get the bits into RAM
u32 segment_addr[32];
u32 base_addr = relocate ? vaddr : 0;
for (int i = 0; i < header->e_phnum; i++) {
Elf32_Phdr *p = segments + i;
INFO_LOG(MASTER_LOG, "Type: %i Vaddr: %08x Filesz: %i Memsz: %i ", p->p_type, p->p_vaddr,
p->p_filesz, p->p_memsz);
if (p->p_type == PT_LOAD) {
segment_addr[i] = base_addr + p->p_vaddr;
memcpy(Memory::GetPointer(segment_addr[i]), GetSegmentPtr(i), p->p_filesz);
INFO_LOG(MASTER_LOG, "Loadable Segment Copied to %08x, size %08x", segment_addr[i],
p->p_memsz);
}
}
INFO_LOG(MASTER_LOG, "Done loading.");
return true;
}
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;
}
bool ElfReader::LoadSymbols() {
bool hasSymbols = false;
SectionID sec = GetSectionByName(".symtab");
if (sec != -1) {
int stringSection = sections[sec].sh_link;
const char *stringBase = (const char *)GetSectionDataPtr(stringSection);
//We have a symbol table!
Elf32_Sym *symtab = (Elf32_Sym *)(GetSectionDataPtr(sec));
int numSymbols = sections[sec].sh_size / sizeof(Elf32_Sym);
for (int sym = 0; sym < numSymbols; sym++) {
int size = symtab[sym].st_size;
if (size == 0)
continue;
int type = symtab[sym].st_info & 0xF;
const char *name = stringBase + symtab[sym].st_name;
Symbols::Add(symtab[sym].st_value, name, size, type);
hasSymbols = true;
}
}
return hasSymbols;
}
////////////////////////////////////////////////////////////////////////////////////////////////////
// Loader namespace
namespace Loader {
/// AppLoader_ELF constructor
AppLoader_ELF::AppLoader_ELF(const std::string& filename) : is_loaded(false) {
this->filename = filename;
}
/// AppLoader_NCCH destructor
AppLoader_ELF::~AppLoader_ELF() {
}
/**
* Loads an NCCH file (e.g. from a CCI, or the first NCCH in a CXI)
* @param error_string Pointer to string to put error message if an error has occurred
* @todo Move NCSD parsing out of here and create a separate function for loading these
* @return True on success, otherwise false
*/
ResultStatus AppLoader_ELF::Load() {
INFO_LOG(LOADER, "Loading ELF file %s...", filename.c_str());
if (is_loaded)
return ResultStatus::ErrorAlreadyLoaded;
File::IOFile file(filename, "rb");
if (file.IsOpen()) {
u32 size = (u32)file.GetSize();
std::unique_ptr<u8[]> buffer(new u8[size]);
file.ReadBytes(&buffer[0], size);
ElfReader elf_reader(&buffer[0]);
elf_reader.LoadInto(0x00100000);
Kernel::LoadExec(elf_reader.GetEntryPoint());
} else {
return ResultStatus::Error;
}
return ResultStatus::Success;
}
} // namespace Loader
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