Merge pull request llvm#11790 from swiftlang/jdevlieghere/radar/156111423

[lldb] Correctly detach (rather than kill) when connecting with gdb-remote

Author: JDevlieghere

lldb/packages/Python/lldbsuite/test/gdbclientutils.py

@@ -4,7 +4,9 @@
 import threading
 import socket
 import traceback
+from enum import Enum
 from lldbsuite.support import seven
+from typing import Optional, List, Tuple, Union, Sequence
 
 
 def checksum(message):
@@ -74,6 +76,35 @@ def hex_decode_bytes(hex_bytes):
     return out
 
 
+class PacketDirection(Enum):
+    RECV = "recv"
+    SEND = "send"
+
+
+class PacketLog:
+    def __init__(self):
+        self._packets: list[tuple[PacketDirection, str]] = []
+
+    def add_sent(self, packet: str):
+        self._packets.append((PacketDirection.SEND, packet))
+
+    def add_received(self, packet: str):
+        self._packets.append((PacketDirection.RECV, packet))
+
+    def get_sent(self):
+        return [
+            pkt for direction, pkt in self._packets if direction == PacketDirection.SEND
+        ]
+
+    def get_received(self):
+        return [
+            pkt for direction, pkt in self._packets if direction == PacketDirection.RECV
+        ]
+
+    def __iter__(self):
+        return iter(self._packets)
+
+
 class MockGDBServerResponder:
     """
     A base class for handling client packets and issuing server responses for
@@ -89,21 +120,33 @@ class MockGDBServerResponder:
     registerCount = 40
     packetLog = None
 
-    class RESPONSE_DISCONNECT:
-        pass
+    class SpecialResponse(Enum):
+        RESPONSE_DISCONNECT = 0
+        RESPONSE_NONE = 1
 
-    class RESPONSE_NONE:
-        pass
+    RESPONSE_DISCONNECT = SpecialResponse.RESPONSE_DISCONNECT
+    RESPONSE_NONE = SpecialResponse.RESPONSE_NONE
+    Response = Union[str, SpecialResponse]
 
     def __init__(self):
-        self.packetLog = []
+        self.packetLog = PacketLog()
 
-    def respond(self, packet):
+    def respond(self, packet: str) -> Sequence[Response]:
         """
         Return the unframed packet data that the server should issue in response
         to the given packet received from the client.
         """
-        self.packetLog.append(packet)
+        self.packetLog.add_received(packet)
+        response = self._respond_impl(packet)
+        if not isinstance(response, list):
+            response = [response]
+        for part in response:
+            if isinstance(part, self.SpecialResponse):
+                continue
+            self.packetLog.add_sent(part)
+        return response
+
+    def _respond_impl(self, packet) -> Union[Response, List[Response]]:
         if packet is MockGDBServer.PACKET_INTERRUPT:
             return self.interrupt()
         if packet == "c":
@@ -649,24 +692,28 @@ def _handlePacket(self, packet):
             # adding validation code to make sure the client only sends ACKs
             # when it's supposed to.
             return
-        response = ""
+        response = [""]
         # We'll handle the ack stuff here since it's not something any of the
         # tests will be concerned about, and it'll get turned off quickly anyway.
         if self._shouldSendAck:
             self._socket.sendall(seven.bitcast_to_bytes("+"))
         if packet == "QStartNoAckMode":
             self._shouldSendAck = False
-            response = "OK"
+            response = ["OK"]
         elif self.responder is not None:
             # Delegate everything else to our responder
             response = self.responder.respond(packet)
+        # MockGDBServerResponder no longer returns non-lists but others like
+        # ReverseTestBase still do
         if not isinstance(response, list):
             response = [response]
         for part in response:
             if part is MockGDBServerResponder.RESPONSE_NONE:
                 continue
             if part is MockGDBServerResponder.RESPONSE_DISCONNECT:
                 raise self.TerminateConnectionException()
+            # Should have handled the non-str's above
+            assert isinstance(part, str)
             self._sendPacket(part)
 
     PACKET_ACK = object()

lldb/packages/Python/lldbsuite/test/lldbgdbclient.py

@@ -10,7 +10,7 @@ class GDBRemoteTestBase(TestBase):
     Base class for GDB client tests.
 
     This class will setup and start a mock GDB server for the test to use.
-    It also provides assertPacketLogContains, which simplifies the checking
+    It also provides assertPacketLogReceived, which simplifies the checking
     of packets sent by the client.
     """
 
@@ -60,30 +60,32 @@ def connect(self, target, plugin="gdb-remote"):
         self.assertTrue(process, PROCESS_IS_VALID)
         return process
 
-    def assertPacketLogContains(self, packets, log=None):
+    def assertPacketLogReceived(self, packets, log: PacketLog = None):
         """
-        Assert that the mock server's packet log contains the given packets.
+        Assert that the mock server's packet log received the given packets.
 
         The packet log includes all packets sent by the client and received
-        by the server.  This fuction makes it easy to verify that the client
+        by the server.  This function makes it easy to verify that the client
         sent the expected packets to the server.
 
         The check does not require that the packets be consecutive, but does
         require that they are ordered in the log as they ordered in the arg.
         """
         if log is None:
-            log = self.server.responder.packetLog
+            received = self.server.responder.packetLog.get_received()
+        else:
+            received = log.get_received()
         i = 0
         j = 0
 
-        while i < len(packets) and j < len(log):
-            if log[j] == packets[i]:
+        while i < len(packets) and j < len(received):
+            if received[j] == packets[i]:
                 i += 1
             j += 1
         if i < len(packets):
             self.fail(
                 "Did not receive: %s\nLast 10 packets:\n\t%s"
-                % (packets[i], "\n\t".join(log))
+                % (packets[i], "\n\t".join(received))
             )
 
 

lldb/source/Target/Process.cpp

@@ -3441,6 +3441,7 @@ Status Process::ConnectRemote(llvm::StringRef remote_url) {
       if (state == eStateStopped || state == eStateCrashed) {
         // If we attached and actually have a process on the other end, then
         // this ended up being the equivalent of an attach.
+        SetShouldDetach(true);
         CompleteAttach();
 
         // This delays passing the stopped event to listeners till

lldb/test/API/functionalities/gdb_remote_client/TestConnectRemoteDetach.py

@@ -0,0 +1,67 @@
+"""
+Test that ConnectRemote sets ShouldDetach flag correctly.
+
+When connecting to a remote process that stops after connection,
+the process should be marked for detach (not kill) on destruction.
+"""
+
+import lldb
+from lldbsuite.test.lldbtest import *
+from lldbsuite.test.decorators import *
+from lldbsuite.test.gdbclientutils import *
+from lldbsuite.test.lldbgdbclient import GDBRemoteTestBase
+from lldbsuite.test import lldbutil
+
+
+class TestConnectRemoteDetach(GDBRemoteTestBase):
+    """Test that ConnectRemote properly sets ShouldDetach flag."""
+
+    class StoppedResponder(MockGDBServerResponder):
+        """A responder that returns a stopped process."""
+
+        def qfThreadInfo(self):
+            return "m1"
+
+        def qsThreadInfo(self):
+            return "l"
+
+        def qC(self):
+            return "QC1"
+
+        def haltReason(self):
+            # Return that we're stopped
+            return "T05thread:1;"
+
+        def cont(self):
+            # Stay stopped
+            return "T05thread:1;"
+
+        def D(self):
+            # Detach packet: this is what we want to verify gets called.
+            return "OK"
+
+        def k(self):
+            # Kill packet: this is what we want to verify doesn't get called.
+            raise RuntimeError("should not receive k(ill) packet")
+
+    def test_connect_remote_sets_detach(self):
+        """Test that ConnectRemote to a stopped process sets ShouldDetach."""
+        self.server.responder = self.StoppedResponder()
+
+        target = self.createTarget("a.yaml")
+        process = self.connect(target)
+
+        # Wait for the process to be in stopped state after connecting.
+        # When ConnectRemote connects to a remote process that is stopped,
+        # it should call SetShouldDetach(true) before CompleteAttach().
+        lldbutil.expect_state_changes(
+            self, self.dbg.GetListener(), process, [lldb.eStateStopped]
+        )
+
+        # Now destroy the process. Because ShouldDetach was set to true
+        # during ConnectRemote, this should send a 'D' (detach) packet
+        # rather than a 'k' (kill) packet when the process is destroyed.
+        process.Destroy()
+
+        # Verify that the (D)etach packet was sent.
+        self.assertPacketLogReceived(["D"])

lldb/test/API/functionalities/gdb_remote_client/TestContinue.py

@@ -41,7 +41,7 @@ def qfThreadInfo(self):
         lldbutil.expect_state_changes(
             self, self.dbg.GetListener(), process, [lldb.eStateExited]
         )
-        self.assertPacketLogContains(["vCont;C13:401"])
+        self.assertPacketLogReceived(["vCont;C13:401"])
 
     def test_continue_no_vCont(self):
         class MyResponder(self.BaseResponder):
@@ -61,7 +61,7 @@ def other(self, packet):
         lldbutil.expect_state_changes(
             self, self.dbg.GetListener(), process, [lldb.eStateExited]
         )
-        self.assertPacketLogContains(["Hc401", "C13"])
+        self.assertPacketLogReceived(["Hc401", "C13"])
 
     def test_continue_multiprocess(self):
         class MyResponder(self.BaseResponder):
@@ -74,4 +74,4 @@ class MyResponder(self.BaseResponder):
         lldbutil.expect_state_changes(
             self, self.dbg.GetListener(), process, [lldb.eStateExited]
         )
-        self.assertPacketLogContains(["vCont;C13:p400.401"])
+        self.assertPacketLogReceived(["vCont;C13:p400.401"])