public override void Relocate(Program program)
{
DumpRel32(loader);
DumpRela32(loader);
foreach (var relSection in loader.Sections)
{
if (relSection.Type == SectionHeaderType.SHT_REL)
{
var sectionSymbols = loader.Symbols[relSection.LinkedSection];
var referringSection = relSection.RelocatedSection;
var rdr = loader.CreateReader(relSection.FileOffset);
for (uint i = 0; i < relSection.EntryCount(); ++i)
{
var rel = Elf32_Rel.Read(rdr);
var sym = sectionSymbols[(int)(rel.r_info >> 8)];
RelocateEntry(program, sym, referringSection, rel);
}
}
else if (relSection.Type == SectionHeaderType.SHT_RELA)
{
var sectionSymbols = loader.Symbols[relSection.LinkedSection];
var referringSection = relSection.RelocatedSection;
var rdr = loader.CreateReader(relSection.FileOffset);
for (uint i = 0; i < relSection.EntryCount(); ++i)
{
var rela = Elf32_Rela.Read(rdr);
var sym = sectionSymbols[(int)(rela.r_info >> 8)];
RelocateEntry(program, sym, referringSection, rela);
}
}
}
}
private void ApplyRelocation(Elf32_Rel rel)
{
// http://flint.cs.yale.edu/cs422/doc/ELF_Format.pdf
// this is probably mostly wrong
long val = 0;
long A = rel.Addend;
// since all symbols were moved by the same amount, just add _loadoffset here
long S = _symlist[rel.SymbolIdx].Value + _loadoffset;
long B = _loadoffset;
switch (rel.Type)
{
case 0: val = 0; break;
case 1: val = S + A; break;
case 2: throw new NotImplementedException();
case 3: throw new NotImplementedException();
case 4: throw new NotImplementedException();
case 5: val = 0; break;
case 6: val = S; break;
case 7: val = S; break;
case 8: val = B + A; break;
case 9: throw new NotImplementedException();
case 10: throw new NotImplementedException();
default: throw new InvalidOperationException();
}
byte[] tmp = new byte[4];
Marshal.Copy((IntPtr)(rel.Address + _loadoffset), tmp, 0, 4);
long currentVal = BitConverter.ToUInt32(tmp, 0);
tmp = BitConverter.GetBytes((uint)(currentVal + val));
Marshal.Copy(tmp, 0, (IntPtr)(rel.Address + _loadoffset), 4);
}
protected void DumpRel32(ElfLoader32 loader)
{
foreach (var section in loader.Sections.Where(s => s.Type == SectionHeaderType.SHT_REL))
{
Debug.Print("REL: offset {0:X} symbol section {1}, relocating in section {2}",
section.FileOffset,
section.LinkedSection.Name,
section.RelocatedSection.Name);
var symbols = loader.Symbols[section.LinkedSection.FileOffset];
var rdr = loader.CreateReader(section.FileOffset);
for (uint i = 0; i < section.EntryCount(); ++i)
{
var rel = Elf32_Rel.Read(rdr);
Debug.Print(" off:{0:X8} type:{1,-16} {3,3} {2}",
rel.r_offset,
RelocationTypeToString(rel.r_info & 0xFF),
symbols[(int)(rel.r_info >> 8)].Name,
(int)(rel.r_info >> 8));
}
}
}
protected void DumpRel32(ElfLoader32 loader)
{
foreach (var section in loader.Sections.Where(s => s.Type == SectionHeaderType.SHT_REL))
{
ElfImageLoader.trace.Inform("REL: offset {0:X} symbol section {1}, relocating in section {2}",
section.FileOffset,
section.LinkedSection.Name,
section.RelocatedSection.Name);
loader.Symbols.TryGetValue(section.LinkedSection.FileOffset, out var symbols);
var rdr = loader.CreateReader(section.FileOffset);
for (uint i = 0; i < section.EntryCount(); ++i)
{
var rel = Elf32_Rel.Read(rdr);
ElfImageLoader.trace.Verbose(
" off:{0:X8} type:{1,-16} {3,3} {2}",
rel.r_offset,
RelocationTypeToString(rel.r_info & 0xFF),
symbols != null ? symbols[(int)(rel.r_info >> 8)].Name : "<nosym>",
(int)(rel.r_info >> 8));
}
}
}
private void ApplyRelocation(Elf32_Rel rel)
{
// http://flint.cs.yale.edu/cs422/doc/ELF_Format.pdf
// this is probably mostly wrong
long val = 0;
long A = rel.Addend;
// since all symbols were moved by the same amount, just add _loadoffset here
long S = _symlist[rel.SymbolIdx].Value + _loadoffset;
long B = _loadoffset;
switch (rel.Type)
{
case 0: val = 0; break;
case 1: val = S + A; break;
case 2: throw new NotImplementedException();
case 3: throw new NotImplementedException();
case 4: throw new NotImplementedException();
case 5: val = 0; break;
case 6: val = S; break;
case 7: val = S; break;
case 8: val = B + A; break;
case 9: throw new NotImplementedException();
case 10: throw new NotImplementedException();
default: throw new InvalidOperationException();
}
byte[] tmp = new byte[4];
Marshal.Copy((IntPtr)(rel.Address + _loadoffset), tmp, 0, 4);
long currentVal = BitConverter.ToUInt32(tmp, 0);
tmp = BitConverter.GetBytes((uint)(currentVal + val));
Marshal.Copy(tmp, 0, (IntPtr)(rel.Address + _loadoffset), 4);
}
public override void RelocateEntry(Program program, ElfSymbol symbol, ElfSection referringSection, Elf32_Rel rel)
{
if (loader.Sections.Count <= symbol.SectionIndex)
{
return;
}
if (symbol.SectionIndex == 0)
{
return;
}
var symSection = loader.Sections[(int)symbol.SectionIndex];
var addr = referringSection.Address + rel.r_offset;
var S = symbol.Value;
uint P = (uint)addr.ToLinear();
uint PP = P;
var relR = program.CreateImageReader(addr);
var relW = program.CreateImageWriter(addr);
int sh = 0;
uint mask = 0;
uint A = 0;
switch ((MIPSrt)(rel.r_info & 0xFF))
{
case MIPSrt.R_MIPS_NONE: return;
case MIPSrt.R_MIPS_REL32:
break;
/*
* R_MIPS_NONE 0 none local none
* R_MIPS_16 1 V–half16 external S + sign–extend(A)
* 1 V–half16 local S + sign–extend(A)
* R_MIPS_32 2 T–word32 external S + A
* 2 T–word32 local S + A
* R_MIPS_REL32 3 T–word32 external A – EA + S
* R_MIPS_REL32 3 T–word32 local A – EA + S
* R_MIPS_26 4 T–targ26 local (((A << 2) | \
* (P & 0xf0000000) + S) >> 2
* 4 T–targ26 external (sign–extend(A < 2) + S) >> 2
* R_MIPS_HI16 5 T–hi16 external ((AHL + S) – \
* (short)(AHL + S)) >> 16
* 5 T–hi16 local ((AHL + S) – \
* (short)(AHL + S)) >> 16
* 5 V–hi16 _gp_disp (AHL + GP – P) – (short) \
* (AHL + GP – P)) >> 16
* R_MIPS_LO16 6 T–lo16 external AHL + S
* 6 T–lo16 local AHL + S
* 6 V–lo16 _gp_disp AHL + GP – P + 4
* R_MIPS_GPREL16 7 V–rel16 external sign–extend(A) + S + GP
* 7 V–rel16 local sign–extend(A) + S + GP0 – GP
* R_MIPS_LITERAL 8 V–lit16 local sign–extend(A) + L
* R_MIPS_GOT16 9 V–rel16 external G
* 9 V–rel16 local see below
* R_MIPS_PC16 10 V–pc16 external sign–extend(A) + S – P
* R_MIPS_CALL16 11 V–rel16 external G
* R_MIPS_GPREL32 12 T–word32 local A + S + GP0 – GP
* R_MIPS_GOTHI16 21 T-hi16 external (G - (short)G) >> 16 + A
* R_MIPS_GOTLO16 22 T-lo16 external G & 0xffff
* R_MIPS_CALLHI16 30 T-hi16 external (G - (short)G) >> 16 + A
* R_MIPS_CALLLO16 31 T-lo16 external G & 0xffff */
}
var w = relR.ReadUInt32();
w += ((uint)(S + A + P) >> sh) & mask;
relW.WriteUInt32(w);
}
public virtual void RelocateEntry(Program program, ElfSymbol symbol, ElfSection referringSection, Elf32_Rel rel)
{
}
