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/*
* Copyright (c) 2020, Itamar S. <itamar8910@gmail.com>
*
* SPDX-License-Identifier: BSD-2-Clause
*/
#include <AK/Assertions.h>
#include <AK/HashMap.h>
#include <AK/NonnullOwnPtr.h>
#include <AK/StringBuilder.h>
#include <LibC/sys/arch/i386/regs.h>
#include <LibCore/ArgsParser.h>
#include <LibCore/File.h>
#include <LibDebug/DebugSession.h>
#include <LibELF/Image.h>
#include <LibX86/Disassembler.h>
#include <LibX86/Instruction.h>
#include <signal.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <syscall.h>
#include <unistd.h>
static OwnPtr<Debug::DebugSession> g_debug_session;
static bool g_should_output_color = false;
static void handle_sigint(int)
{
outln("Debugger: SIGINT");
// The destructor of DebugSession takes care of detaching
g_debug_session = nullptr;
}
static void print_function_call(String function_name, size_t depth)
{
for (size_t i = 0; i < depth; ++i) {
out(" ");
}
outln("=> {}", function_name);
}
static void print_syscall(PtraceRegisters& regs, size_t depth)
{
for (size_t i = 0; i < depth; ++i) {
out(" ");
}
const char* begin_color = g_should_output_color ? "\033[34;1m" : "";
const char* end_color = g_should_output_color ? "\033[0m" : "";
#if ARCH(I386)
outln("=> {}SC_{}({:#x}, {:#x}, {:#x}){}",
begin_color,
Syscall::to_string((Syscall::Function)regs.eax),
regs.edx,
regs.ecx,
regs.ebx,
end_color);
#else
outln("=> {}SC_{}({:#x}, {:#x}, {:#x}){}",
begin_color,
Syscall::to_string((Syscall::Function)regs.rax),
regs.rdx,
regs.rcx,
regs.rbx,
end_color);
#endif
}
static NonnullOwnPtr<HashMap<void*, X86::Instruction>> instrument_code()
{
auto instrumented = make<HashMap<void*, X86::Instruction>>();
g_debug_session->for_each_loaded_library([&](const Debug::DebugSession::LoadedLibrary& lib) {
lib.debug_info->elf().for_each_section_of_type(SHT_PROGBITS, [&](const ELF::Image::Section& section) {
if (section.name() != ".text")
return IterationDecision::Continue;
X86::SimpleInstructionStream stream((const u8*)((uintptr_t)lib.file->data() + section.offset()), section.size());
X86::Disassembler disassembler(stream);
for (;;) {
auto offset = stream.offset();
void* instruction_address = (void*)(section.address() + offset + lib.base_address);
auto insn = disassembler.next();
if (!insn.has_value())
break;
if (insn.value().mnemonic() == "RET" || insn.value().mnemonic() == "CALL") {
g_debug_session->insert_breakpoint(instruction_address);
instrumented->set(instruction_address, insn.value());
}
}
return IterationDecision::Continue;
});
return IterationDecision::Continue;
});
return instrumented;
}
int main(int argc, char** argv)
{
if (pledge("stdio proc exec rpath sigaction ptrace", nullptr) < 0) {
perror("pledge");
return 1;
}
if (isatty(STDOUT_FILENO))
g_should_output_color = true;
const char* command = nullptr;
Core::ArgsParser args_parser;
args_parser.add_positional_argument(command,
"The program to be traced, along with its arguments",
"program", Core::ArgsParser::Required::Yes);
args_parser.parse(argc, argv);
auto result = Debug::DebugSession::exec_and_attach(command);
if (!result) {
warnln("Failed to start debugging session for: \"{}\"", command);
exit(1);
}
g_debug_session = result.release_nonnull();
auto instrumented = instrument_code();
struct sigaction sa;
memset(&sa, 0, sizeof(struct sigaction));
sa.sa_handler = handle_sigint;
sigaction(SIGINT, &sa, nullptr);
size_t depth = 0;
bool new_function = true;
g_debug_session->run(Debug::DebugSession::DesiredInitialDebugeeState::Running, [&](Debug::DebugSession::DebugBreakReason reason, Optional<PtraceRegisters> regs) {
if (reason == Debug::DebugSession::DebugBreakReason::Exited) {
outln("Program exited.");
return Debug::DebugSession::DebugDecision::Detach;
}
if (reason == Debug::DebugSession::DebugBreakReason::Syscall) {
print_syscall(regs.value(), depth + 1);
return Debug::DebugSession::DebugDecision::ContinueBreakAtSyscall;
}
#if ARCH(I386)
const FlatPtr ip = regs.value().eip;
#else
const FlatPtr ip = regs.value().rip;
#endif
if (new_function) {
auto function_name = g_debug_session->symbolicate(ip);
print_function_call(function_name.value().symbol, depth);
new_function = false;
return Debug::DebugSession::ContinueBreakAtSyscall;
}
auto instruction = instrumented->get((void*)ip).value();
if (instruction.mnemonic() == "RET") {
if (depth != 0)
--depth;
return Debug::DebugSession::ContinueBreakAtSyscall;
}
// FIXME: we could miss some leaf functions that were called with a jump
VERIFY(instruction.mnemonic() == "CALL");
++depth;
new_function = true;
return Debug::DebugSession::DebugDecision::SingleStep;
});
}
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