[Lldb-commits] [lldb] [lldb] Implement basic support for reverse-continue (PR #112079)

[Pavel Labath via lldb-commits]

================
@@ -0,0 +1,185 @@
+import logging
+import os
+import os.path
+import random
+
+import lldb
+from lldbsuite.test.lldbtest import *
+from lldbsuite.test.gdbclientutils import *
+import lldbgdbserverutils
+from lldbsuite.support import seven
+
+
+class GDBProxyTestBase(TestBase):
+    """
+    Base class for gdbserver proxy tests.
+
+    This class will setup and start a mock GDB server for the test to use.
+    It pases through requests to a regular lldb-server/debugserver and
+    forwards replies back to the LLDB under test.
+    """
+
+    """The gdbserver that we implement."""
+    server = None
+    """The inner lldb-server/debugserver process that we proxy requests into."""
+    monitor_server = None
+    monitor_sock = None
+
+    server_socket_class = TCPServerSocket
+
+    DEFAULT_TIMEOUT = 20 * (10 if ("ASAN_OPTIONS" in os.environ) else 1)
+
+    _verbose_log_handler = None
+    _log_formatter = logging.Formatter(fmt="%(asctime)-15s %(levelname)-8s %(message)s")
+    _validate_checksums = True
+
+    def setUpBaseLogging(self):
+        self.logger = logging.getLogger(__name__)
+
+        if len(self.logger.handlers) > 0:
+            return  # We have set up this handler already
+
+        self.logger.propagate = False
+        self.logger.setLevel(logging.DEBUG)
+
+        # log all warnings to stderr
+        handler = logging.StreamHandler()
+        handler.setLevel(logging.WARNING)
+        handler.setFormatter(self._log_formatter)
+        self.logger.addHandler(handler)
+
+    def setUp(self):
+        TestBase.setUp(self)
+
+        self.setUpBaseLogging()
+
+        if self.isVerboseLoggingRequested():
+            # If requested, full logs go to a log file
+            log_file_name = self.getLogBasenameForCurrentTest() + "-proxy.log"
+            self._verbose_log_handler = logging.FileHandler(log_file_name)
+            self._verbose_log_handler.setFormatter(self._log_formatter)
+            self._verbose_log_handler.setLevel(logging.DEBUG)
+            self.logger.addHandler(self._verbose_log_handler)
+
+        if lldbplatformutil.getPlatform() == "macosx":
+            self.debug_monitor_exe = lldbgdbserverutils.get_debugserver_exe()
+            self.debug_monitor_extra_args = []
+            # debugserver does not produce correct checksums
+            self._validate_checksums = False
+        else:
+            self.debug_monitor_exe = lldbgdbserverutils.get_lldb_server_exe()
+            self.debug_monitor_extra_args = ["gdbserver"]
+        self.assertIsNotNone(self.debug_monitor_exe)
+
+        self.server = MockGDBServer(self.server_socket_class())
+        self.server.responder = self
+
+    def tearDown(self):
+        # TestBase.tearDown will kill the process, but we need to kill it early
+        # so its client connection closes and we can stop the server before
+        # finally calling the base tearDown.
+        if self.process() is not None:
+            self.process().Kill()
+        self.server.stop()
+
+        self.logger.removeHandler(self._verbose_log_handler)
+        self._verbose_log_handler = None
+
+        TestBase.tearDown(self)
+
+    def isVerboseLoggingRequested(self):
+        # We will report our detailed logs if the user requested that the "gdb-remote" channel is
+        # logged.
+        return any(("gdb-remote" in channel) for channel in lldbtest_config.channels)
+
+    def connect(self, target):
+        """
+        Create a process by connecting to the mock GDB server.
+        """
+        self.prep_debug_monitor_and_inferior()
+        self.server.start()
+
+        listener = self.dbg.GetListener()
+        error = lldb.SBError()
+        process = target.ConnectRemote(
+            listener, self.server.get_connect_url(), "gdb-remote", error
+        )
+        self.assertTrue(error.Success(), error.description)
+        self.assertTrue(process, PROCESS_IS_VALID)
+        return process
+
+    def get_next_port(self):
+        return 12000 + random.randint(0, 3999)
+
+    def prep_debug_monitor_and_inferior(self):
+        inferior_exe_path = self.getBuildArtifact("a.out")
+        self.connect_to_debug_monitor([inferior_exe_path])
+        self.assertIsNotNone(self.monitor_server)
+        self.initial_handshake()
+
+    def initial_handshake(self):
+        self.monitor_server.send_packet(seven.bitcast_to_bytes("+"))
+        reply = seven.bitcast_to_string(self.monitor_server.get_normal_packet())
+        self.assertEqual(reply, "+")
+        self.monitor_server.send_packet(seven.bitcast_to_bytes("QStartNoAckMode"))
+        reply = seven.bitcast_to_string(self.monitor_server.get_normal_packet())
+        self.assertEqual(reply, "+")
+        reply = seven.bitcast_to_string(self.monitor_server.get_normal_packet())
+        self.assertEqual(reply, "OK")
+        self.monitor_server.send_packet(seven.bitcast_to_bytes("+"))
+        reply = seven.bitcast_to_string(self.monitor_server.get_normal_packet())
+        self.assertEqual(reply, "+")
+
+    def get_debug_monitor_command_line_args(self, connect_address, launch_args):
+        return (
+            self.debug_monitor_extra_args
+            + ["--reverse-connect", connect_address]
+            + launch_args
+        )
+
+    def launch_debug_monitor(self, launch_args):
+        family, type, proto, _, addr = socket.getaddrinfo(
+            "localhost", 0, proto=socket.IPPROTO_TCP
+        )[0]
+        sock = socket.socket(family, type, proto)
+        sock.settimeout(self.DEFAULT_TIMEOUT)
+        sock.bind(addr)
+        sock.listen(1)
+        addr = sock.getsockname()
+        connect_address = "[{}]:{}".format(*addr)
+
+        commandline_args = self.get_debug_monitor_command_line_args(
+            connect_address, launch_args
+        )
+
+        # Start the server.
+        self.logger.info(f"Spawning monitor {commandline_args}")
+        monitor_process = self.spawnSubprocess(
+            self.debug_monitor_exe, commandline_args, install_remote=False
+        )
+        self.assertIsNotNone(monitor_process)
+
+        self.monitor_sock = sock.accept()[0]
+        self.monitor_sock.settimeout(self.DEFAULT_TIMEOUT)
+        return monitor_process
+
+    def connect_to_debug_monitor(self, launch_args):
+        monitor_process = self.launch_debug_monitor(launch_args)
+        # Turn off checksum validation because debugserver does not produce
+        # correct checksums.
+        self.monitor_server = lldbgdbserverutils.Server(
+            self.monitor_sock,
+            monitor_process,
+            validate_checksums=self._validate_checksums,
----------------
labath wrote:

The way this works is that we don't require the server to compute the checksum in no-ack mode, so instead of a constructor property, I'd make this something that's settable at runtime, and then call it after you've received the `OK` QStartNoAckMode response. To simplify things, I think it'd be best to set it unconditionally rather than just on darwin/debugserver (I'm not sure whether we want to enforce that lldb-server always computes the checksum, but I'm pretty sure we don't want to do that here).

https://github.com/llvm/llvm-project/pull/112079