private void LoadImportReferencesFromRelPlt(Dictionary <Address, ImportReference> importReferences)
{
var rel_plt = loader.GetSectionInfoByName(".rel.plt");
var symtab = rel_plt.LinkedSection;
var plt = loader.GetSectionInfoByName(".plt");
var relRdr = loader.CreateReader(rel_plt.FileOffset);
uint entries = rel_plt.EntryCount();
for (uint i = 0; i < entries; ++i)
{
uint offset;
if (!relRdr.TryReadUInt32(out offset))
{
return;
}
uint info;
if (!relRdr.TryReadUInt32(out info))
{
return;
}
uint sym = info >> 8;
string symStr = loader.GetSymbolName(symtab, sym);
var addr = plt.Address + (i + 1) * plt.EntrySize;
importReferences[addr] = new NamedImportReference(
addr, null, symStr);
}
}
/// <remarks>
/// According to the ELF PPC32 documentation, the .rela.plt and .plt tables
/// should contain the same number of entries, even if the individual entry
/// sizes are distinct. The entries in .real.plt refer to symbols while the
/// entries in .plt are (writeable) pointers. Any caller that jumps to one
/// of pointers in the .plt table is a "trampoline", and should be replaced
/// in the decompiled code with just a call to the symbol obtained from the
/// .real.plt section.
/// </remarks>
public override void Relocate(Program program)
{
base.Relocate(program);
var rela_plt = loader.GetSectionInfoByName(".rela.plt");
if (rela_plt == null)
{
return;
}
var plt = loader.GetSectionInfoByName(".plt");
var relaRdr = loader.CreateReader(rela_plt.FileOffset);
var pltRdr = loader.CreateReader(plt.FileOffset);
for (int i = 0; i < rela_plt.EntryCount(); ++i)
{
// Read the .rela.plt entry
uint offset;
if (!relaRdr.TryReadUInt32(out offset))
{
return;
}
uint info;
if (!relaRdr.TryReadUInt32(out info))
{
return;
}
int addend;
if (!relaRdr.TryReadInt32(out addend))
{
return;
}
// Read the .plt entry. We don't care about its contents,
// only its address. Anyone accessing that address is
// trying to access the symbol.
uint thunkAddress;
if (!pltRdr.TryReadUInt32(out thunkAddress))
{
break;
}
uint sym = info >> 8;
string symStr = loader.GetSymbolName(rela_plt.LinkedSection, sym);
var addr = plt.Address + (uint)i * 4;
program.ImportReferences.Add(
addr,
new NamedImportReference(addr, null, symStr));
}
}