/*
* Copyright (c) 2020, Andreas Kling <kling@serenityos.org>
*
* SPDX-License-Identifier: BSD-2-Clause
*/
#include <AK/Debug.h>
#include <AK/Demangle.h>
#include <AK/OwnPtr.h>
#include <AK/QuickSort.h>
#include <AK/Vector.h>
#include <LibCore/ArgsParser.h>
#include <LibCore/MappedFile.h>
#include <LibCore/System.h>
#include <LibELF/Image.h>
#include <LibMain/Main.h>
#include <LibX86/Disassembler.h>
#include <LibX86/ELFSymbolProvider.h>
#include <string.h>
ErrorOr<int> serenity_main(Main::Arguments args)
{
StringView path {};
Core::ArgsParser args_parser;
args_parser.set_general_help(
"Disassemble an executable, and show human-readable "
"assembly code for each function.");
args_parser.add_positional_argument(path, "Path to i386 binary file", "path");
args_parser.parse(args);
RefPtr<Core::MappedFile> file;
u8 const* asm_data = nullptr;
size_t asm_size = 0;
if ((TRY(Core::System::stat(path))).st_size > 0) {
file = TRY(Core::MappedFile::map(path));
asm_data = static_cast<u8 const*>(file->data());
asm_size = file->size();
}
struct Symbol {
size_t value;
size_t size;
StringView name;
size_t address() const { return value; }
size_t address_end() const { return value + size; }
bool contains(size_t virtual_address) { return address() <= virtual_address && virtual_address < address_end(); }
};
Vector<Symbol> symbols;
size_t file_offset = 0;
Vector<Symbol>::Iterator current_symbol = symbols.begin();
OwnPtr<X86::ELFSymbolProvider> symbol_provider; // nullptr for non-ELF disassembly.
OwnPtr<ELF::Image> elf;
if (asm_size >= 4 && strncmp(reinterpret_cast<char const*>(asm_data), "\u007fELF", 4) == 0) {
elf = make<ELF::Image>(asm_data, asm_size);
if (elf->is_valid()) {
symbol_provider = make<X86::ELFSymbolProvider>(*elf);
elf->for_each_section_of_type(SHT_PROGBITS, [&](ELF::Image::Section const& section) {
// FIXME: Disassemble all SHT_PROGBITS sections, not just .text.
if (section.name() != ".text")
return IterationDecision::Continue;
asm_data = reinterpret_cast<u8 const*>(section.raw_data());
asm_size = section.size();
file_offset = section.address();
return IterationDecision::Break;
});
symbols.ensure_capacity(elf->symbol_count() + 1);
symbols.append({ 0, 0, StringView() }); // Sentinel.
elf->for_each_symbol([&](ELF::Image::Symbol const& symbol) {
symbols.append({ symbol.value(), symbol.size(), symbol.name() });
return IterationDecision::Continue;
});
quick_sort(symbols, [](auto& a, auto& b) {
if (a.value != b.value)
return a.value < b.value;
if (a.size != b.size)
return a.size < b.size;
return a.name < b.name;
});
if constexpr (DISASM_DUMP_DEBUG) {
for (size_t i = 0; i < symbols.size(); ++i)
dbgln("{}: {:p}, {}", symbols[i].name, symbols[i].value, symbols[i].size);
}
}
}
X86::SimpleInstructionStream stream(asm_data, asm_size);
X86::Disassembler disassembler(stream);
bool is_first_symbol = true;
bool current_instruction_is_in_symbol = false;
for (;;) {
auto offset = stream.offset();
auto insn = disassembler.next();
if (!insn.has_value())
break;
// Prefix regions of instructions belonging to a symbol with the symbol's name.
// Separate regions of instructions belonging to distinct symbols with newlines,
// and separate regions of instructions not belonging to symbols from regions belonging to symbols with newlines.
// Interesting cases:
// - More than 1 symbol covering a region of instructions (ICF, D1/D2)
// - Symbols of size 0 that don't cover any instructions but are at an address (want to print them, separated from instructions both before and after)
// Invariant: current_symbol is the largest instruction containing insn, or it is the largest instruction that has an address less than the instruction's address.
size_t virtual_offset = file_offset + offset;
if (current_symbol < symbols.end() && !current_symbol->contains(virtual_offset)) {
if (!is_first_symbol && current_instruction_is_in_symbol) {
// The previous instruction was part of a symbol that doesn't cover the current instruction, so separate it from the current instruction with a newline.
outln();
current_instruction_is_in_symbol = (current_symbol + 1 < symbols.end() && (current_symbol + 1)->contains(virtual_offset));
}
// Try to find symbol covering current instruction, if one exists.
while (current_symbol + 1 < symbols.end() && !(current_symbol + 1)->contains(virtual_offset) && (current_symbol + 1)->address() <= virtual_offset) {
++current_symbol;
if (!is_first_symbol)
outln("\n({} ({:p}-{:p}))\n", demangle(current_symbol->name), current_symbol->address(), current_symbol->address_end());
}
while (current_symbol + 1 < symbols.end() && (current_symbol + 1)->contains(virtual_offset)) {
if (!is_first_symbol && !current_instruction_is_in_symbol)
outln();
++current_symbol;
current_instruction_is_in_symbol = true;
outln("{} ({:p}-{:p}):", demangle(current_symbol->name), current_symbol->address(), current_symbol->address_end());
}
is_first_symbol = false;
}
size_t length = insn.value().length();
StringBuilder builder;
builder.appendff("{:p} ", virtual_offset);
for (size_t i = 0; i < 7; i++) {
if (i < length)
builder.appendff("{:02x} ", asm_data[offset + i]);
else
builder.append(" "sv);
}
builder.append(" "sv);
builder.append(insn.value().to_deprecated_string(virtual_offset, symbol_provider));
outln("{}", builder.string_view());
for (size_t bytes_printed = 7; bytes_printed < length; bytes_printed += 7) {
builder.clear();
builder.appendff("{:p} ", virtual_offset + bytes_printed);
for (size_t i = bytes_printed; i < bytes_printed + 7 && i < length; i++)
builder.appendff(" {:02x}", asm_data[offset + i]);
outln("{}", builder.string_view());
}
}
return 0;
}