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LibELF: Split do_relocation into do_{direct,plt}_relocation

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No functional changes intended. This is in preparation of a commit that
overhauls how IFUNCs are resolved.

This commit lets us move the implementation of PLT patching from
`DynamicObject` to `DynamicLoader` where all other relocation code
lives. For this, got[2] now stores the loader's address instead of the
object's.
This commit is contained in:
Daniel Bertalan 2023-04-22 11:44:02 +02:00 • committed by Andreas Kling
parent c4e0f5e5ee
commit cd45c2d295
4 changed files with 82 additions and 56 deletions
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27
Userland/Libraries/LibELF/DynamicObject.cpp
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@ -480,33 +480,6 @@ NonnullRefPtr<DynamicObject> DynamicObject::create(DeprecatedString const& filep
return adopt_ref(*new DynamicObject(filepath, base_address, dynamic_section_address));
}
// offset is in PLT relocation table
VirtualAddress DynamicObject::patch_plt_entry(u32 relocation_offset)
{
auto relocation = plt_relocation_section().relocation_at_offset(relocation_offset);
VERIFY(relocation.type() == R_X86_64_JUMP_SLOT || relocation.type() == R_AARCH64_JUMP_SLOT);
auto symbol = relocation.symbol();
auto relocation_address = (FlatPtr*)relocation.address().as_ptr();
VirtualAddress symbol_location;
auto result = DynamicLoader::lookup_symbol(symbol);
if (result.has_value()) {
symbol_location = result.value().address;
if (result.value().type == STT_GNU_IFUNC)
symbol_location = VirtualAddress { reinterpret_cast<IfuncResolver>(symbol_location.get())() };
} else if (symbol.bind() != STB_WEAK) {
dbgln("did not find symbol while doing relocations for library {}: {}", m_filepath, symbol.name());
VERIFY_NOT_REACHED();
}
dbgln_if(DYNAMIC_LOAD_DEBUG, "DynamicLoader: Jump slot relocation: putting {} ({}) into PLT at {}", symbol.name(), symbol_location, (void*)relocation_address);
*relocation_address = symbol_location.get();
return symbol_location;
}
u32 DynamicObject::HashSymbol::gnu_hash() const
{
if (!m_gnu_hash.has_value())