public void LinkStatic(uint baseAddress, Dictionary <string, uint> externalSymbols)
{
_baseAddress = new Word(WordType.AbsoluteAddr, Mapper.Remap(baseAddress));
DoLink(externalSymbols);
}
public void LinkDynamic(Dictionary <String, uint> externalSymbols)
{
_baseAddress = new Word(WordType.RelativeAddr, 0);
DoLink(externalSymbols);
}
private string[] ParseSymbolTable(Elf elf, Elf.ElfSection symtab, Elf.ElfSection strtab, Dictionary <string, Symbol> locals)
{
if (symtab.sh_entsize != 16)
{
throw new InvalidDataException("Invalid symbol table format (sh_entsize != 16)");
}
if (strtab.sh_type != Elf.ElfSection.Type.SHT_STRTAB)
{
throw new InvalidDataException("String table does not have type SHT_STRTAB");
}
var symbolNames = new List <string>();
var reader = new BinaryReader(new MemoryStream(symtab.data));
int count = symtab.data.Length / 16;
// always ignore the first symbol
symbolNames.Add(null);
reader.BaseStream.Seek(16, SeekOrigin.Begin);
for (int i = 1; i < count; i++)
{
// Read info from the ELF
uint st_name = reader.ReadBigUInt32();
uint st_value = reader.ReadBigUInt32();
uint st_size = reader.ReadBigUInt32();
byte st_info = reader.ReadByte();
byte st_other = reader.ReadByte();
ushort st_shndx = reader.ReadBigUInt16();
Elf.SymBind bind = (Elf.SymBind)(st_info >> 4);
Elf.SymType type = (Elf.SymType)(st_info & 0xF);
string name = Util.ExtractNullTerminatedString(strtab.data, (int)st_name);
symbolNames.Add(name);
if (name.Length == 0 || st_shndx == 0)
{
continue;
}
// What location is this referencing?
Elf.ElfSection refSection;
if (st_shndx < 0xFF00)
{
refSection = elf.Sections[st_shndx];
}
else if (st_shndx == 0xFFF1) // absolute symbol
{
refSection = null;
}
else
{
throw new InvalidDataException("unknown section index found in symbol table");
}
Word addr;
if (st_shndx == 0xFFF1)
{
// Absolute symbol
addr = new Word(WordType.AbsoluteAddr, st_value);
}
else if (st_shndx < 0xFF00)
{
// Part of a section
var section = elf.Sections[st_shndx];
if (!_sectionBases.ContainsKey(section))
{
continue; // skips past symbols we don't care about, like DWARF junk
}
addr = _sectionBases[section] + st_value;
}
else
{
throw new NotImplementedException("unknown section index found in symbol table");
}
switch (bind)
{
case Elf.SymBind.STB_LOCAL:
if (locals.ContainsKey(name))
{
throw new InvalidDataException("redefinition of local symbol " + name);
}
locals[name] = new Symbol {
address = addr, size = st_size
};
_symbolSizes[addr] = st_size;
break;
case Elf.SymBind.STB_GLOBAL:
if (_globalSymbols.ContainsKey(name) && !_globalSymbols[name].isWeak)
{
throw new InvalidDataException("redefinition of global symbol " + name);
}
_globalSymbols[name] = new Symbol {
address = addr, size = st_size
};
_symbolSizes[addr] = st_size;
break;
case Elf.SymBind.STB_WEAK:
if (!_globalSymbols.ContainsKey(name))
{
_globalSymbols[name] = new Symbol {
address = addr, size = st_size, isWeak = true
};
_symbolSizes[addr] = st_size;
}
break;
}
}
return(symbolNames.ToArray());
}
private void WriteUInt32(Word addr, uint value)
{
Util.InjectUInt32(_memory, addr - _baseAddress, value);
}
private void WriteUInt16(Word addr, ushort value)
{
Util.InjectUInt16(_memory, addr - _baseAddress, value);
}
private uint ReadUInt32(Word addr)
{
return(Util.ExtractUInt32(_memory, addr - _baseAddress));
}
private ushort ReadUInt16(Word addr)
{
return(Util.ExtractUInt16(_memory, addr - _baseAddress));
}