From 7598c4225e619363dfb5277a8f282d55f924d1a2 Mon Sep 17 00:00:00 2001
From: Xusheng <xusheng@vector35.com>
Date: Mon, 26 Dec 2022 12:19:05 +0800
Subject: [PATCH] Fix LLDB launch failure when an ELF binary has no dynamic
 loader. Fix https://github.com/Vector35/debugger/issues/407

---
 core/adapters/lldbadapter.cpp | 18 +++++++++++++++++-
 core/adapters/lldbadapter.h   |  5 +++++
 test/debugger_test.py         |  6 ------
 3 files changed, 22 insertions(+), 7 deletions(-)

diff --git a/core/adapters/lldbadapter.cpp b/core/adapters/lldbadapter.cpp
index 37a00ff7..e90cab1c 100644
--- a/core/adapters/lldbadapter.cpp
+++ b/core/adapters/lldbadapter.cpp
@@ -45,6 +45,8 @@ LldbAdapter::LldbAdapter(BinaryView* data) : DebugAdapter(data)
 	if (!m_debugger.IsValid())
 		LogWarn("Invalid debugger");
 
+	m_isElFWithoutDynamicLoader = IsELFWithoutDynamicLoader(data);
+
 	// Set auto-confirm to true so operations that ask for confirmation will proceed automatically.
 	// Otherwise, the confirmation prompt will be sent to the terminal that BN is launched from, which is a very
 	// confusing behavior.
@@ -132,6 +134,20 @@ void LldbAdapter::ApplyBreakpoints()
 }
 
 
+bool LldbAdapter::IsELFWithoutDynamicLoader(BinaryView* data)
+{
+	if (!data)
+		return false;
+
+	auto name = data->GetTypeName();
+	if (name != "ELF")
+		return false;
+
+	auto syms = data->GetSymbolsByName("__elf_interp");
+	return syms.empty();
+}
+
+
 bool LldbAdapter::Execute(const std::string& path, const LaunchConfigurations& configs)
 {
 	return ExecuteWithArgs(path, "", "", configs);
@@ -189,7 +205,7 @@ bool LldbAdapter::ExecuteWithArgs(const std::string& path, const std::string& ar
 		AddBreakpoint(ModuleNameAndOffset(path, m_entryPoint - m_start));
 
 	std::string launchCommand = "process launch";
-	if (Settings::Instance()->Get<bool>("debugger.stopAtSystemEntryPoint"))
+	if (Settings::Instance()->Get<bool>("debugger.stopAtSystemEntryPoint") || m_isElFWithoutDynamicLoader)
 		launchCommand += " --stop-at-entry";
 
 	if (configs.requestTerminalEmulator)
diff --git a/core/adapters/lldbadapter.h b/core/adapters/lldbadapter.h
index fc25248c..a6f54bd9 100644
--- a/core/adapters/lldbadapter.h
+++ b/core/adapters/lldbadapter.h
@@ -36,6 +36,11 @@ namespace BinaryNinjaDebugger {
 		bool m_targetActive;
 		std::vector<ModuleNameAndOffset> m_pendingBreakpoints {};
 
+		// To launch an ELF without dynamic loader, we must set `debugger.stopAtSystemEntryPoint`.
+		// Otherwise, the process will run freely on its own and not stop.
+		bool m_isElFWithoutDynamicLoader = false;
+		bool IsELFWithoutDynamicLoader(BinaryView* data);
+
 	public:
 		LldbAdapter(BinaryView* data);
 		virtual ~LldbAdapter();
diff --git a/test/debugger_test.py b/test/debugger_test.py
index 70a7a946..0bf57f70 100644
--- a/test/debugger_test.py
+++ b/test/debugger_test.py
@@ -264,13 +264,7 @@ def test_assembly_code(self):
             fpath = name_to_fpath('asmtest', 'x86_64')
             bv = BinaryViewType.get_view_of_file(fpath)
             dbg = DebuggerController(bv)
-            if platform.system() == 'Linux':
-                Settings().set_bool('debugger.stopAtSystemEntryPoint', True)
-
             self.assertTrue(dbg.launch())
-            if platform.system() == 'Linux':
-                Settings().set_bool('debugger.stopAtSystemEntryPoint', False)
-
             entry = dbg.live_view.entry_point
             self.assertEqual(dbg.ip, entry)