[Lldb-commits] [PATCH] D45573: Report more precise error message when attach fails

[Pavel Labath via Phabricator via lldb-commits]

labath created this revision.
labath added reviewers: jingham, JDevlieghere.

If the remote stub sends a specific error message instead of just a E??
code, we can use this to display a more informative error message
instead of just the generic "unable to attach" message.

I write a test for this using the SB API.
On the console this will show up like:
(lldb) process attach ...
error: attach failed: <STUB-MESSAGE>

if the stub supports error messages, or:
error: attach failed: "Error ??"

if it doesn't.


https://reviews.llvm.org/D45573

Files:
  packages/Python/lldbsuite/test/functionalities/gdb_remote_client/TestGDBRemoteClient.py
  packages/Python/lldbsuite/test/functionalities/gdb_remote_client/gdbclientutils.py
  source/Plugins/Process/gdb-remote/ProcessGDBRemote.cpp


Index: source/Plugins/Process/gdb-remote/ProcessGDBRemote.cpp
===================================================================
--- source/Plugins/Process/gdb-remote/ProcessGDBRemote.cpp
+++ source/Plugins/Process/gdb-remote/ProcessGDBRemote.cpp
@@ -3808,8 +3808,8 @@
                 }
                 // E01 code from vAttach means that the attach failed
                 if (::strstr(continue_cstr, "vAttach") != NULL &&
-                    response.GetError() == 0x1) {
-                  process->SetExitStatus(-1, "unable to attach");
+                    response.GetStatus().Fail()) {
+                  process->SetExitStatus(-1, response.GetStatus().AsCString());
                 } else {
                   process->SetExitStatus(-1, "lost connection");
                 }
Index: packages/Python/lldbsuite/test/functionalities/gdb_remote_client/gdbclientutils.py
===================================================================
--- packages/Python/lldbsuite/test/functionalities/gdb_remote_client/gdbclientutils.py
+++ packages/Python/lldbsuite/test/functionalities/gdb_remote_client/gdbclientutils.py
@@ -126,6 +126,8 @@
             return self.qfThreadInfo()
         if packet == "qC":
             return self.qC()
+        if packet == "QEnableErrorStrings":
+            return self.QEnableErrorStrings()
         if packet == "?":
             return self.haltReason()
         if packet[0] == "H":
@@ -137,6 +139,9 @@
             if data is not None:
                 return self._qXferResponse(data, has_more)
             return ""
+        if packet.startswith("vAttach;"):
+            pid = packet.partition(';')[2]
+            return self.vAttach(int(pid, 16))
         if packet[0] == "Z":
             return self.setBreakpoint(packet)
         return self.other(packet)
@@ -177,6 +182,9 @@
     def qC(self):
         return "QC0"
 
+    def QEnableErrorStrings(self):
+        return "OK"
+
     def haltReason(self):
         # SIGINT is 2, return type is 2 digit hex string
         return "S02"
@@ -187,6 +195,9 @@
     def _qXferResponse(self, data, has_more):
         return "%s%s" % ("m" if has_more else "l", escape_binary(data))
 
+    def vAttach(self, pid):
+        raise self.UnexpectedPacketException()
+
     def selectThread(self, op, thread_id):
         return "OK"
 
Index: packages/Python/lldbsuite/test/functionalities/gdb_remote_client/TestGDBRemoteClient.py
===================================================================
--- packages/Python/lldbsuite/test/functionalities/gdb_remote_client/TestGDBRemoteClient.py
+++ packages/Python/lldbsuite/test/functionalities/gdb_remote_client/TestGDBRemoteClient.py
@@ -11,3 +11,28 @@
         target = self.createTarget("a.yaml")
         process = self.connect(target)
         self.assertPacketLogContains(["qProcessInfo", "qfThreadInfo"])
+
+    def test_attach_fail(self):
+        error_msg = "mock-error-msg"
+
+        class MyResponder(MockGDBServerResponder):
+            # Pretend we don't have any process during the initial queries.
+            def qC(self):
+                return "E42"
+
+            def qfThreadInfo(self):
+                return "OK" # No threads.
+
+            # Then, when we are asked to attach, error out.
+            def vAttach(self, pid):
+                return "E42;" + error_msg.encode("hex")
+
+        self.server.responder = MyResponder()
+
+        target = self.dbg.CreateTarget("")
+        process = self.connect(target)
+        lldbutil.expect_state_changes(self, self.dbg.GetListener(), process, [lldb.eStateConnected])
+
+        error = lldb.SBError()
+        target.AttachToProcessWithID(lldb.SBListener(), 47, error)
+        self.assertEquals(error_msg, error.GetCString())


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