Experimental support for auto-reloading when switching threads

This is particularly important when switching threads in a coredump, when you can't just single-step to ensure everything gets reloaded.

pwndbg/__init__.py

@@ -111,8 +111,20 @@ for line in pre_commands.strip().splitlines():
 msg = "Loaded %i commands.  Type pwndbg for a list." % len(pwndbg.commands._Command.commands)
 print(pwndbg.color.red(msg))
 
-@pwndbg.memoize.reset_on_stop
+cur = (gdb.selected_inferior(), gdb.selected_thread())
+
 def prompt_hook(*a):
+    global cur
+    new = (gdb.selected_inferior(), gdb.selected_thread())
+
+    if cur != new:
+        pwndbg.events.after_reload()
+        cur = new
+
+    prompt_hook_on_stop(*a)
+
+@pwndbg.memoize.reset_on_stop
+def prompt_hook_on_stop(*a):
     with pwndbg.stdio.stdio:
         pwndbg.commands.context.context()
 

pwndbg/argv.py

@@ -1,3 +1,5 @@
+import gdb
+
 import pwndbg.arch
 import pwndbg.events
 import pwndbg.memory
@@ -21,7 +23,11 @@ def update():
     ptrsize = pwndbg.arch.ptrsize
     ptrbits  = 8 * ptrsize
 
-    argc = pwndbg.memory.u(sp, ptrbits)
+    try:
+        argc = pwndbg.memory.u(sp, ptrbits)
+    except:
+        return
+
     sp += ptrsize
 
     argv = sp

pwndbg/events.py

@@ -110,12 +110,13 @@ def stop(func):        return connect(func, gdb.events.stop, 'stop')
 def start(func):       return connect(func, gdb.events.start, 'start')
 
 def after_reload():
-    return
-    # if gdb.selected_inferior().pid:
-    #     for f in registered[gdb.events.new_objfile]:
-    #         f()
-    #     for f in registered[gdb.events.stop]:
-    #         f()
+    if gdb.selected_inferior().pid:
+        for f in registered[gdb.events.start]:
+            f()
+        for f in registered[gdb.events.new_objfile]:
+            f()
+        for f in registered[gdb.events.stop]:
+            f()
 
 def on_reload():
     for event, functions in registered.items():