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Loader: Stabilize loader & Use shared libraries everywhere :^)

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The dynamic loader is now stable enough to be used everywhere in the
system - so this commit does just that.
No More .a Files, Long Live .so's!
This commit is contained in:
Itamar 2020-10-17 14:39:36 +03:00 • committed by Andreas Kling
parent c917fcbac4
commit efe4da57df
28 changed files with 401 additions and 173 deletions
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56
Libraries/LibELF/DynamicObject.cpp
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@ -32,6 +32,16 @@
#include <stdio.h>
#include <string.h>
// #define DYNAMIC_OBJECT_VERBOSE
#ifdef DYNAMIC_OBJECT_VERBOSE
# define VERBOSE(fmt, ...) dbgprintf(fmt, ##__VA_ARGS__)
#else
# define VERBOSE(fmt, ...) \
do { \
} while (0)
#endif
namespace ELF {
static const char* name_for_dtag(Elf32_Sword d_tag);
@ -63,8 +73,8 @@ void DynamicObject::dump() const
if (m_has_soname)
builder.appendf("DT_SONAME: %s\n", soname()); // FIXME: Valdidate that this string is null terminated?
dbgprintf("Dynamic section at address %p contains %zu entries:\n", m_dynamic_address.as_ptr(), num_dynamic_sections);
dbgprintf("%s", builder.to_string().characters());
VERBOSE("Dynamic section at address %p contains %zu entries:\n", m_dynamic_address.as_ptr(), num_dynamic_sections);
VERBOSE("%s", builder.to_string().characters());
}
void DynamicObject::parse()
@ -402,4 +412,46 @@ NonnullRefPtr<DynamicObject> DynamicObject::construct(VirtualAddress base_addres
return adopt(*new DynamicObject(base_address, dynamic_section_address));
}
// offset is in PLT relocation table
Elf32_Addr DynamicObject::patch_plt_entry(u32 relocation_offset)
{
auto relocation = plt_relocation_section().relocation_at_offset(relocation_offset);
ASSERT(relocation.type() == R_386_JMP_SLOT);
auto sym = relocation.symbol();
if (StringView { sym.name() } == "__cxa_demangle") {
dbgln("__cxa_demangle is currently not supported for shared objects");
// FIXME: Where is it defined?
ASSERT_NOT_REACHED();
}
u8* relocation_address = relocation.address().as_ptr();
auto res = lookup_symbol(sym);
if (!res.found) {
dbgln("did not find symbol: {} ", sym.name());
ASSERT_NOT_REACHED();
}
u32 symbol_location = res.address;
VERBOSE("DynamicLoader: Jump slot relocation: putting %s (%p) into PLT at %p\n", sym.name(), symbol_location, relocation_address);
*(u32*)relocation_address = symbol_location;
return symbol_location;
}
DynamicObject::SymbolLookupResult DynamicObject::lookup_symbol(const ELF::DynamicObject::Symbol& symbol) const
{
VERBOSE("looking up symbol: %s\n", symbol.name());
if (!symbol.is_undefined()) {
VERBOSE("symbol is defiend in its object\n");
return { true, symbol.value(), (FlatPtr)symbol.address().as_ptr(), &symbol.object() };
}
ASSERT(m_global_symbol_lookup_func);
return m_global_symbol_lookup_func(symbol.name());
}
} // end namespace ELF