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 "common/common.h"
#include "common/symbols.h"
#include "core/mem_map.h"
#include "core/loader/elf.h"
//void bswap(Elf32_Word &w) {w = Common::swap32(w);}
//void bswap(Elf32_Half &w) {w = Common::swap16(w);}
#define bswap(w) w // Dirty bswap disable for now... 3DS is little endian, anyway
static void byteswapHeader(Elf32_Ehdr &ELF_H)
{
bswap(ELF_H.e_type);
bswap(ELF_H.e_machine);
bswap(ELF_H.e_ehsize);
bswap(ELF_H.e_phentsize);
bswap(ELF_H.e_phnum);
bswap(ELF_H.e_shentsize);
bswap(ELF_H.e_shnum);
bswap(ELF_H.e_shstrndx);
bswap(ELF_H.e_version);
bswap(ELF_H.e_entry);
bswap(ELF_H.e_phoff);
bswap(ELF_H.e_shoff);
bswap(ELF_H.e_flags);
}
static void byteswapSegment(Elf32_Phdr &sec)
{
bswap(sec.p_align);
bswap(sec.p_filesz);
bswap(sec.p_flags);
bswap(sec.p_memsz);
bswap(sec.p_offset);
bswap(sec.p_paddr);
bswap(sec.p_vaddr);
bswap(sec.p_type);
}
static void byteswapSection(Elf32_Shdr &sec)
{
bswap(sec.sh_addr);
bswap(sec.sh_addralign);
bswap(sec.sh_entsize);
bswap(sec.sh_flags);
bswap(sec.sh_info);
bswap(sec.sh_link);
bswap(sec.sh_name);
bswap(sec.sh_offset);
bswap(sec.sh_size);
bswap(sec.sh_type);
}
ElfReader::ElfReader(void *ptr)
{
base = (char*)ptr;
base32 = (u32 *)ptr;
header = (Elf32_Ehdr*)ptr;
byteswapHeader(*header);
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 nameOffset = sections[section].sh_name;
char *ptr = (char*)GetSectionDataPtr(header->e_shstrndx);
if (ptr)
return ptr + nameOffset;
else
return nullptr;
}
bool ElfReader::LoadInto(u32 vaddr)
{
DEBUG_LOG(MASTER_LOG, "String section: %i", header->e_shstrndx);
// Should we relocate?
bRelocate = (header->e_type != ET_EXEC);
if (bRelocate)
{
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 segmentVAddr[32];
u32 baseAddress = bRelocate ? 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)
{
segmentVAddr[i] = baseAddress + p->p_vaddr;
u32 writeAddr = segmentVAddr[i];
const u8 *src = GetSegmentPtr(i);
u8 *dst = Memory::GetPointer(writeAddr);
u32 srcSize = p->p_filesz;
u32 dstSize = p->p_memsz;
u32 *s = (u32*)src;
u32 *d = (u32*)dst;
for (int j = 0; j < (int)(srcSize + 3) / 4; j++)
{
*d++ = /*_byteswap_ulong*/(*s++);
}
if (srcSize < dstSize)
{
//memset(dst + srcSize, 0, dstSize-srcSize); //zero out bss
}
INFO_LOG(MASTER_LOG, "Loadable Segment Copied to %08x, size %08x", writeAddr, 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 bind = symtab[sym].st_info >> 4;
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;
}