Applications: Move to Userland/Applications/

Userland/Applications/Debugger/main.cpp

@@ -0,0 +1,313 @@
+/*
+ * Copyright (c) 2020, Itamar S. <itamar8910@gmail.com>
+ * All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions are met:
+ *
+ * 1. Redistributions of source code must retain the above copyright notice, this
+ *    list of conditions and the following disclaimer.
+ *
+ * 2. Redistributions in binary form must reproduce the above copyright notice,
+ *    this list of conditions and the following disclaimer in the documentation
+ *    and/or other materials provided with the distribution.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
+ * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+ * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
+ * DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE LIABLE
+ * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
+ * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR
+ * SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER
+ * CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
+ * OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+ * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+ */
+
+#include <AK/Assertions.h>
+#include <AK/ByteBuffer.h>
+#include <AK/Demangle.h>
+#include <AK/LogStream.h>
+#include <AK/StringBuilder.h>
+#include <AK/kmalloc.h>
+#include <LibC/sys/arch/i386/regs.h>
+#include <LibCore/ArgsParser.h>
+#include <LibCore/File.h>
+#include <LibDebug/DebugInfo.h>
+#include <LibDebug/DebugSession.h>
+#include <LibLine/Editor.h>
+#include <LibX86/Disassembler.h>
+#include <LibX86/Instruction.h>
+#include <signal.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include <unistd.h>
+
+RefPtr<Line::Editor> editor;
+
+OwnPtr<Debug::DebugSession> g_debug_session;
+
+static void handle_sigint(int)
+{
+    outln("Debugger: SIGINT");
+
+    // The destructor of DebugSession takes care of detaching
+    g_debug_session = nullptr;
+}
+
+static void handle_print_registers(const PtraceRegisters& regs)
+{
+    outln("eax={:08x} ebx={:08x} ecx={:08x} edx={:08x}", regs.eax, regs.ebx, regs.ecx, regs.edx);
+    outln("esp={:08x} ebp={:08x} esi={:08x} edi={:08x}", regs.esp, regs.ebp, regs.esi, regs.edi);
+    outln("eip={:08x} eflags={:08x}", regs.eip, regs.eflags);
+}
+
+static bool handle_disassemble_command(const String& command, void* first_instruction)
+{
+    auto parts = command.split(' ');
+    size_t number_of_instructions_to_disassemble = 5;
+    if (parts.size() == 2) {
+        auto number = parts[1].to_uint();
+        if (!number.has_value())
+            return false;
+        number_of_instructions_to_disassemble = number.value();
+    }
+
+    // FIXME: Instead of using a fixed "dump_size",
+    //        we can feed instructions to the disassembler one by one
+    constexpr size_t dump_size = 0x100;
+    ByteBuffer code;
+    for (size_t i = 0; i < dump_size / sizeof(u32); ++i) {
+        auto value = g_debug_session->peek(reinterpret_cast<u32*>(first_instruction) + i);
+        if (!value.has_value())
+            break;
+        code.append(&value, sizeof(u32));
+    }
+
+    X86::SimpleInstructionStream stream(code.data(), code.size());
+    X86::Disassembler disassembler(stream);
+
+    for (size_t i = 0; i < number_of_instructions_to_disassemble; ++i) {
+        auto offset = stream.offset();
+        auto insn = disassembler.next();
+        if (!insn.has_value())
+            break;
+
+        outln("    {:p} <+{}>:\t{}", offset + reinterpret_cast<size_t>(first_instruction), offset, insn.value().to_string(offset));
+    }
+
+    return true;
+}
+
+static bool insert_breakpoint_at_address(FlatPtr address)
+{
+    return g_debug_session->insert_breakpoint((void*)address);
+}
+
+static bool insert_breakpoint_at_source_position(const String& file, size_t line)
+{
+    auto result = g_debug_session->insert_breakpoint(file, line);
+    if (!result.has_value()) {
+        warnln("Could not insert breakpoint at {}:{}", file, line);
+        return false;
+    }
+    outln("Breakpoint inserted [{}:{} ({}:{:p})]", result.value().file_name, result.value().line_number, result.value().library_name, result.value().address);
+    return true;
+}
+
+static bool insert_breakpoint_at_symbol(const String& symbol)
+{
+    auto result = g_debug_session->insert_breakpoint(symbol);
+    if (!result.has_value()) {
+        warnln("Could not insert breakpoint at symbol: {}", symbol);
+        return false;
+    }
+    outln("Breakpoint inserted [{}:{:p}]", result.value().library_name, result.value().address);
+    return true;
+}
+
+static bool handle_breakpoint_command(const String& command)
+{
+    auto parts = command.split(' ');
+    if (parts.size() != 2)
+        return false;
+
+    auto argument = parts[1];
+    if (argument.is_empty())
+        return false;
+
+    if (argument.contains(":")) {
+        auto source_arguments = argument.split(':');
+        if (source_arguments.size() != 2)
+            return false;
+        auto line = source_arguments[1].to_uint();
+        if (!line.has_value())
+            return false;
+        auto file = source_arguments[0];
+        return insert_breakpoint_at_source_position(file, line.value());
+    }
+    if ((argument.starts_with("0x"))) {
+        return insert_breakpoint_at_address(strtoul(argument.characters() + 2, nullptr, 16));
+    }
+
+    return insert_breakpoint_at_symbol(argument);
+}
+
+static bool handle_examine_command(const String& command)
+{
+    auto parts = command.split(' ');
+    if (parts.size() != 2)
+        return false;
+
+    auto argument = parts[1];
+    if (argument.is_empty())
+        return false;
+
+    if (!(argument.starts_with("0x"))) {
+        return false;
+    }
+    u32 address = strtoul(argument.characters() + 2, nullptr, 16);
+    auto res = g_debug_session->peek((u32*)address);
+    if (!res.has_value()) {
+        printf("could not examine memory at address 0x%x\n", address);
+        return true;
+    }
+    printf("0x%x\n", res.value());
+    return true;
+}
+
+static void print_help()
+{
+    out("Options:\n"
+        "cont - Continue execution\n"
+        "si - step to the next instruction\n"
+        "sl - step to the next source line\n"
+        "line - show the position of the current instruction in the source code\n"
+        "regs - Print registers\n"
+        "dis [number of instructions] - Print disassembly\n"
+        "bp <address/symbol/file:line> - Insert a breakpoint\n"
+        "x <address> - examine dword in memory\n");
+}
+
+int main(int argc, char** argv)
+{
+    editor = Line::Editor::construct();
+
+    if (pledge("stdio proc ptrace exec rpath tty sigaction cpath unix fattr", nullptr) < 0) {
+        perror("pledge");
+        return 1;
+    }
+
+    const char* command = nullptr;
+    Core::ArgsParser args_parser;
+    args_parser.add_positional_argument(command,
+        "The program to be debugged, 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();
+
+    struct sigaction sa;
+    memset(&sa, 0, sizeof(struct sigaction));
+    sa.sa_handler = handle_sigint;
+    sigaction(SIGINT, &sa, nullptr);
+
+    Debug::DebugInfo::SourcePosition previous_source_position;
+    bool in_step_line = false;
+
+    g_debug_session->run(Debug::DebugSession::DesiredInitialDebugeeState::Stopped, [&](Debug::DebugSession::DebugBreakReason reason, Optional<PtraceRegisters> optional_regs) {
+        if (reason == Debug::DebugSession::DebugBreakReason::Exited) {
+            outln("Program exited.");
+            return Debug::DebugSession::DebugDecision::Detach;
+        }
+
+        ASSERT(optional_regs.has_value());
+        const PtraceRegisters& regs = optional_regs.value();
+
+        auto symbol_at_ip = g_debug_session->symbolicate(regs.eip);
+
+        auto source_position = g_debug_session->get_source_position(regs.eip);
+
+        if (in_step_line) {
+            bool no_source_info = !source_position.has_value();
+            if (no_source_info || source_position.value() != previous_source_position) {
+                if (no_source_info)
+                    outln("No source information for current instruction! stoppoing.");
+                in_step_line = false;
+            } else {
+                return Debug::DebugSession::DebugDecision::SingleStep;
+            }
+        }
+
+        if (symbol_at_ip.has_value())
+            outln("Program is stopped at: {:p} ({}:{})", regs.eip, symbol_at_ip.value().library_name, symbol_at_ip.value().symbol);
+        else
+            outln("Program is stopped at: {:p}", regs.eip);
+
+        if (source_position.has_value()) {
+            previous_source_position = source_position.value();
+            outln("Source location: {}:{}", source_position.value().file_path, source_position.value().line_number);
+        } else {
+            outln("(No source location information for the current instruction)");
+        }
+
+        for (;;) {
+            auto command_result = editor->get_line("(sdb) ");
+
+            if (command_result.is_error())
+                return Debug::DebugSession::DebugDecision::Detach;
+
+            auto& command = command_result.value();
+
+            bool success = false;
+            Optional<Debug::DebugSession::DebugDecision> decision;
+
+            if (command.is_empty() && !editor->history().is_empty()) {
+                command = editor->history().last().entry;
+            }
+            if (command == "cont") {
+                decision = Debug::DebugSession::DebugDecision::Continue;
+                success = true;
+            } else if (command == "si") {
+                decision = Debug::DebugSession::DebugDecision::SingleStep;
+                success = true;
+            } else if (command == "sl") {
+                if (source_position.has_value()) {
+                    decision = Debug::DebugSession::DebugDecision::SingleStep;
+                    in_step_line = true;
+                    success = true;
+                } else {
+                    outln("No source location information for the current instruction");
+                }
+            } else if (command == "regs") {
+                handle_print_registers(regs);
+                success = true;
+
+            } else if (command.starts_with("dis")) {
+                success = handle_disassemble_command(command, reinterpret_cast<void*>(regs.eip));
+
+            } else if (command.starts_with("bp")) {
+                success = handle_breakpoint_command(command);
+            } else if (command.starts_with("x")) {
+                success = handle_examine_command(command);
+            }
+
+            if (success && !command.is_empty()) {
+                // Don't add repeated commands to history
+                if (editor->history().is_empty() || editor->history().last().entry != command)
+                    editor->add_to_history(command);
+            }
+            if (!success) {
+                print_help();
+            }
+            if (decision.has_value())
+                return decision.value();
+        }
+    });
+}