[Lldb-commits] [lldb] [lldb] Use correct path for debugserver (PR #131609)

[Yuval Deutscher via lldb-commits]

https://github.com/yuvald-sweet-security updated https://github.com/llvm/llvm-project/pull/131609

>From 6f2d070facaced221295a5b0c48ccb3a41a5048d Mon Sep 17 00:00:00 2001
From: Yuval Deutscher <yuvald at sweet.security>
Date: Mon, 17 Mar 2025 14:37:26 +0200
Subject: [PATCH 1/2] [lldb] Use correct path for debugserver

---
 lldb/tools/lldb-server/SystemInitializerLLGS.h | 9 ++++++++-
 1 file changed, 8 insertions(+), 1 deletion(-)

diff --git a/lldb/tools/lldb-server/SystemInitializerLLGS.h b/lldb/tools/lldb-server/SystemInitializerLLGS.h
index 4469a8ba5f60a..c6020b0dd37da 100644
--- a/lldb/tools/lldb-server/SystemInitializerLLGS.h
+++ b/lldb/tools/lldb-server/SystemInitializerLLGS.h
@@ -11,10 +11,17 @@
 
 #include "lldb/Initialization/SystemInitializer.h"
 #include "lldb/Initialization/SystemInitializerCommon.h"
+#include "lldb/Utility/FileSpec.h"
 
 class SystemInitializerLLGS : public lldb_private::SystemInitializerCommon {
 public:
-  SystemInitializerLLGS() : SystemInitializerCommon(nullptr) {}
+  SystemInitializerLLGS()
+      : SystemInitializerCommon(
+            // Finding the shared libraries directory on lldb-server is broken
+            // since lldb-server isn't dynamically linked with liblldb.so.
+            // Clearing the filespec here causes GetShlibDir to fail and
+            // GetSupportExeDir to fall-back to using the binary path instead.
+            [](lldb_private::FileSpec &file) { file.Clear(); }) {}
 
   llvm::Error Initialize() override;
   void Terminate() override;

>From 1b04782c9db3647d1379346ce36009dc077dddfc Mon Sep 17 00:00:00 2001
From: Yuval Deutscher <yuvald at sweet.security>
Date: Thu, 3 Apr 2025 14:52:43 +0300
Subject: [PATCH 2/2] [lldb] Test running lldb-server through symlink

---
 .../TestPlatformLaunchGDBServer.py            | 51 +++++++++++++++++++
 1 file changed, 51 insertions(+)

diff --git a/lldb/test/API/commands/platform/launchgdbserver/TestPlatformLaunchGDBServer.py b/lldb/test/API/commands/platform/launchgdbserver/TestPlatformLaunchGDBServer.py
index c365bc993e338..e332035d0c767 100644
--- a/lldb/test/API/commands/platform/launchgdbserver/TestPlatformLaunchGDBServer.py
+++ b/lldb/test/API/commands/platform/launchgdbserver/TestPlatformLaunchGDBServer.py
@@ -58,3 +58,54 @@ def test_platform_process_launch_gdb_server(self):
 
         self.runCmd("target create {}".format(self.getBuildArtifact("a.out")))
         self.expect("run", substrs=["unable to launch a GDB server on"], error=True)
+
+    @skipIfRemote
+    # Windows cannot delete the executable while it is running.
+    # On Darwin we may be using debugserver.
+    @skipUnlessPlatform(["linux"])
+    @add_test_categories(["lldb-server"])
+    def test_platform_process_launch_gdb_server(self):
+        self.build()
+
+        hostname = socket.getaddrinfo("localhost", 0, proto=socket.IPPROTO_TCP)[0][4][0]
+        listen_url = "[%s]:0" % hostname
+
+        port_file = self.getBuildArtifact("port")
+        commandline_args = [
+            "platform",
+            "--listen",
+            listen_url,
+            "--socket-file",
+            port_file,
+            "--",
+            self.getBuildArtifact("a.out"),
+            "foo",
+        ]
+
+        # Run lldb-server from a symlink without any binary called "lldb-server" in the directory.
+        llgs_hiding_directory = self.getBuildArtifact("hiding-directory")
+        new_lldb_server_link = self.getBuildArtifact(
+            "lldb-server-with-an-unconventional-name"
+        )
+        new_lldb_server = os.path.join(llgs_hiding_directory, "lldb-server")
+        os.makedirs(llgs_hiding_directory)
+        shutil.copy(lldbgdbserverutils.get_lldb_server_exe(), new_lldb_server)
+        os.symlink(new_lldb_server, new_lldb_server_link)
+
+        self.spawnSubprocess(new_lldb_server_link, commandline_args)
+        socket_id = lldbutil.wait_for_file_on_target(self, port_file)
+
+        new_platform = lldb.SBPlatform("remote-" + self.getPlatform())
+        self.dbg.SetSelectedPlatform(new_platform)
+
+        connect_url = "connect://[%s]:%s" % (hostname, socket_id)
+        self.runCmd("platform connect %s" % connect_url)
+
+        # First connect to lldb-server which spawn a process to handle the connection.
+        # Then remove our new lldb-server so that when it tries to invoke itself as a
+        # gdbserver, it fails.
+        os.remove(new_lldb_server_link)
+        shutil.rmtree(llgs_hiding_directory)
+
+        self.runCmd("target create {}".format(self.getBuildArtifact("a.out")))
+        self.expect("run", substrs=["unable to launch a GDB server on"], error=True)