tumbledemerald-legacy/tools/ramscrgen/elf.cpp
2022-05-19 17:14:13 +00:00

273 lines
7.6 KiB
C++

#include <cstdio>
#include <cstring>
#include <cstdint>
#include <map>
#include <vector>
#include <string>
#include "ramscrgen.h"
#include "elf.h"
#define SHN_COMMON 0xFFF2
static std::string s_elfPath;
static std::string s_archiveFilePath;
static std::string s_archiveObjectPath;
static FILE *s_file;
static std::uint32_t s_sectionHeaderOffset;
static int s_sectionHeaderEntrySize;
static int s_sectionCount;
static int s_shstrtabIndex;
static std::uint32_t s_symtabOffset;
static std::uint32_t s_strtabOffset;
static std::uint32_t s_symbolCount;
static std::uint32_t s_elfFileOffset;
struct Symbol
{
std::uint32_t nameOffset;
std::uint32_t size;
};
static void Seek(long offset)
{
if (std::fseek(s_file, s_elfFileOffset + offset, SEEK_SET) != 0)
FATAL_ERROR("error: failed to seek to %ld in \"%s\"", offset, s_elfPath.c_str());
}
static void Skip(long offset)
{
if (std::fseek(s_file, offset, SEEK_CUR) != 0)
FATAL_ERROR("error: failed to skip %ld bytes in \"%s\"", offset, s_elfPath.c_str());
}
static std::uint32_t ReadInt8()
{
int c = std::fgetc(s_file);
if (c < 0)
FATAL_ERROR("error: unexpected EOF when reading ELF file \"%s\"\n", s_elfPath.c_str());
return c;
}
static std::uint32_t ReadInt16()
{
std::uint32_t val = 0;
val |= ReadInt8();
val |= ReadInt8() << 8;
return val;
}
static std::uint32_t ReadInt32()
{
std::uint32_t val = 0;
val |= ReadInt8();
val |= ReadInt8() << 8;
val |= ReadInt8() << 16;
val |= ReadInt8() << 24;
return val;
}
static std::string ReadString()
{
std::string s;
char c;
while ((c = ReadInt8()) != 0)
s += c;
return s;
}
static void VerifyElfIdent()
{
char expectedMagic[4] = { 0x7F, 'E', 'L', 'F' };
char magic[4];
if (std::fread(magic, 4, 1, s_file) != 1)
FATAL_ERROR("error: failed to read ELF magic from \"%s\"\n", s_elfPath.c_str());
if (std::memcmp(magic, expectedMagic, 4) != 0)
FATAL_ERROR("error: ELF magic did not match in \"%s\"\n", s_elfPath.c_str());
if (std::fgetc(s_file) != 1)
FATAL_ERROR("error: \"%s\" not 32-bit ELF\n", s_elfPath.c_str());
if (std::fgetc(s_file) != 1)
FATAL_ERROR("error: \"%s\" not little-endian ELF\n", s_elfPath.c_str());
}
static void VerifyAr()
{
char expectedMagic[8] = {'!', '<', 'a', 'r', 'c', 'h', '>', '\n'};
char magic[8];
if (std::fread(magic, 8, 1, s_file) != 1)
FATAL_ERROR("error: failed to read AR magic from \"%s\"\n", s_archiveFilePath.c_str());
if (std::memcmp(magic, expectedMagic, 8) != 0)
FATAL_ERROR("error: AR magic did not match in \"%s\"\n", s_archiveFilePath.c_str());
}
static void ReadElfHeader()
{
Seek(0x20);
s_sectionHeaderOffset = ReadInt32();
Seek(0x2E);
s_sectionHeaderEntrySize = ReadInt16();
s_sectionCount = ReadInt16();
s_shstrtabIndex = ReadInt16();
}
static void FindArObj()
{
char file_ident[17] = {0};
char filesize_s[11] = {0};
char expectedEndMagic[2] = { 0x60, 0x0a };
char end_magic[2];
std::size_t filesize;
Seek(8);
while (!std::feof(s_file)) {
if (std::fread(file_ident, 16, 1, s_file) != 1)
FATAL_ERROR("error: failed to read file ident in \"%s\"\n", s_archiveFilePath.c_str());
Skip(32);
if (std::fread(filesize_s, 10, 1, s_file) != 1)
FATAL_ERROR("error: failed to read filesize in \"%s\"\n", s_archiveFilePath.c_str());
if (std::fread(end_magic, 2, 1, s_file) != 1)
FATAL_ERROR("error: failed to read end sentinel in \"%s\"\n", s_archiveFilePath.c_str());
if (std::memcmp(end_magic, expectedEndMagic, 2) != 0)
FATAL_ERROR("error: corrupted archive header in \"%s\" at \"%s\"\n", s_archiveFilePath.c_str(), file_ident);
char * ptr = std::strchr(file_ident, '/');
if (ptr != nullptr)
*ptr = 0;
filesize = std::strtoul(filesize_s, nullptr, 10);
if (std::strncmp(s_archiveObjectPath.c_str(), file_ident, 16) == 0) {
s_elfFileOffset = std::ftell(s_file);
return;
}
Skip(filesize);
}
FATAL_ERROR("error: could not find object \"%s\" in archive \"%s\"\n", s_archiveObjectPath.c_str(), s_archiveFilePath.c_str());
}
static std::string GetSectionName(std::uint32_t shstrtabOffset, int index)
{
Seek(s_sectionHeaderOffset + s_sectionHeaderEntrySize * index);
std::uint32_t nameOffset = ReadInt32();
Seek(shstrtabOffset + nameOffset);
return ReadString();
}
static void FindTableOffsets()
{
s_symtabOffset = 0;
s_strtabOffset = 0;
Seek(s_sectionHeaderOffset + s_sectionHeaderEntrySize * s_shstrtabIndex + 0x10);
std::uint32_t shstrtabOffset = ReadInt32();
for (int i = 0; i < s_sectionCount; i++)
{
std::string name = GetSectionName(shstrtabOffset, i);
if (name == ".symtab")
{
if (s_symtabOffset)
FATAL_ERROR("error: mutiple .symtab sections found in \"%s\"\n", s_elfPath.c_str());
Seek(s_sectionHeaderOffset + s_sectionHeaderEntrySize * i + 0x10);
s_symtabOffset = ReadInt32();
std::uint32_t size = ReadInt32();
s_symbolCount = size / 16;
}
else if (name == ".strtab")
{
if (s_strtabOffset)
FATAL_ERROR("error: mutiple .strtab sections found in \"%s\"\n", s_elfPath.c_str());
Seek(s_sectionHeaderOffset + s_sectionHeaderEntrySize * i + 0x10);
s_strtabOffset = ReadInt32();
}
}
if (!s_symtabOffset)
FATAL_ERROR("error: couldn't find .symtab section in \"%s\"\n", s_elfPath.c_str());
if (!s_strtabOffset)
FATAL_ERROR("error: couldn't find .strtab section in \"%s\"\n", s_elfPath.c_str());
}
static std::map<std::string, std::uint32_t> GetCommonSymbols_Shared()
{
VerifyElfIdent();
ReadElfHeader();
FindTableOffsets();
std::map<std::string, std::uint32_t> commonSymbols;
std::vector<Symbol> commonSymbolVec;
Seek(s_symtabOffset);
for (std::uint32_t i = 0; i < s_symbolCount; i++)
{
Symbol sym;
sym.nameOffset = ReadInt32();
Skip(4);
sym.size = ReadInt32();
Skip(2);
std::uint16_t sectionIndex = ReadInt16();
if (sectionIndex == SHN_COMMON)
commonSymbolVec.push_back(sym);
}
for (const Symbol& sym : commonSymbolVec)
{
Seek(s_strtabOffset + sym.nameOffset);
std::string name = ReadString();
commonSymbols[name] = sym.size;
}
return commonSymbols;
}
std::map<std::string, std::uint32_t> GetCommonSymbolsFromLib(std::string sourcePath, std::string libpath)
{
std::size_t colonPos = libpath.find(':');
if (colonPos == std::string::npos)
FATAL_ERROR("error: missing colon separator in libfile \"%s\"\n", s_elfPath.c_str());
s_archiveObjectPath = libpath.substr(colonPos + 1);
s_archiveFilePath = sourcePath + "/" + libpath.substr(1, colonPos - 1);
s_elfPath = sourcePath + "/" + libpath.substr(1);
s_file = std::fopen(s_archiveFilePath.c_str(), "rb");
if (s_file == NULL)
FATAL_ERROR("error: failed to open \"%s\" for reading\n", s_archiveFilePath.c_str());
VerifyAr();
FindArObj();
return GetCommonSymbols_Shared();
}
std::map<std::string, std::uint32_t> GetCommonSymbols(std::string sourcePath, std::string path)
{
s_elfFileOffset = 0;
if (path[0] == '*')
return GetCommonSymbolsFromLib(sourcePath, path);
s_elfPath = sourcePath + "/" + path;
s_file = std::fopen(s_elfPath.c_str(), "rb");
if (s_file == NULL)
FATAL_ERROR("error: failed to open \"%s\" for reading\n", path.c_str());
return GetCommonSymbols_Shared();
}