GP-6541: post-review

GP-6541: tests working
GP-6541: docs
GP-6541: basic errors

Ghidra/Debug/Debugger-agent-drgn/data/debugger-launchers/local-drgn.sh

@@ -26,7 +26,7 @@
 #@icon icon.debugger
 #@help drgn#attach
 #@depends Debugger-rmi-trace
-#@env OPT_TARGET_PID:int=44068 "PID" "The target's process id"
+#@env OPT_TARGET_PID:int=-1 "PID" "The target's process id"
 
 export OPT_TARGET_KIND="user" 
 # sudo -E drgn -p "$OPT_TARGET_PID" ../support/local-drgn.py

Ghidra/Debug/Debugger-agent-drgn/src/main/help/help/topics/drgn/drgn.html

@@ -66,8 +66,19 @@ echo 0 > /proc/sys/kernel/yama/ptrace_scope
 
     <H3>Setup</H3>
 
-    <P>You must have Meta's <B>drgn</B> installed on the local system. No other setup is required.
-    Note: requires root access - you will be prompted for a password in the Terminal.</P>
+    <P>You must have Meta's <B>drgn</B> installed on the local system. Symbols for the running kernel
+	should also be installed, as described in the <B>drgn</B> documentation, e.g. using:</P>
+	    <UL style="list-style-type: none">
+	      <LI>
+<PRE>
+sudo dnf debuginfo-install kernel-$(uname -r)
+</PRE>
+	      </LI>
+	    </UL>
+
+    <P>Note: this launcher requires root access - you will be prompted for a password in the Terminal. 
+	Also note: running <B>drgn</B> as root may leave artifacts in the active python cache with root
+    permissions, which may need to be deleted manually when rebuilding.</P>
 
     <H3>Options</H3>
 

Ghidra/Debug/Debugger-agent-drgn/src/main/py/src/ghidradrgn/commands.py

@@ -266,16 +266,17 @@ def ghidra_trace_create(start_trace: bool = True) -> None:
 
     global prog
     prog = Program()
+
     kind = os.getenv('OPT_TARGET_KIND')
     if kind == "kernel":
         prog.set_kernel()
+        util.selected_pid = 0
     elif kind == "coredump":
         img = os.getenv('OPT_TARGET_IMG')
         if img is None:
             return
         prog.set_core_dump(img)
-        if '/' in img:
-            img = img[img.rindex('/')+1:]
+        util.selected_pid = 0
     else:
         pid = os.getenv('OPT_TARGET_PID')
         if pid is not None:
@@ -288,18 +289,34 @@ def ghidra_trace_create(start_trace: bool = True) -> None:
     except drgn.MissingDebugInfoError as e:
         print(e)
 
-    if hasattr(drgn, 'Module') or kind == "coredump":
-        if kind == "kernel":
-            img = prog.main_module().name  # type: ignore
-            util.selected_tid = next(prog.threads()).tid
-        elif kind == "coredump":
-            util.selected_tid = prog.crashed_thread().tid
-        else:
-            img = prog.main_module().name  # type: ignore
-            util.selected_tid = prog.main_thread().tid
+    # Set display name and active thread
+    display = "noname"
+    if kind == "kernel":
+        display = "kernel"
+        if hasattr(prog, "main_module"):
+            if hasattr(prog.main_module(), "name"):
+                display = prog.main_module().name  # type: ignore
+        try:
+            threads = prog.threads()
+        except Exception as e:
+            print(f"ERROR: {e}")
+            return
+        util.selected_tid = next(prog.threads()).tid
+    elif kind == "coredump":
+        display = img
+        if '/' in display:
+            display = display[display.rindex('/')+1:]
+        util.selected_tid = prog.crashed_thread().tid
+    else:
+        display = str(pid)
+        if hasattr(prog, "main_thread"):
+            if hasattr(prog.main_thread(), "name"):
+                display = prog.main_thread().name
+        util.selected_tid = prog.main_thread().tid
+    util.selected_level = 0
 
     if start_trace:
-        ghidra_trace_start(img)
+        ghidra_trace_start(display)
 
     PROGRAMS[util.selected_pid] = prog
 
@@ -1108,7 +1125,11 @@ def put_threads(running: bool = False) -> None:
     trace = STATE.require_trace()
     keys = []
     # Set running=True to avoid thread changes, even while stopped
-    threads = prog.threads()
+    try:
+        threads = prog.threads()
+    except Exception as e:
+        print(f"ERROR: {e}")
+        return
     for i, t in enumerate(threads):
         nthrd = t.tid
         tpath = THREAD_PATTERN.format(procnum=nproc, tnum=nthrd)