Properly handle shutdown sequence in both prototype and dbus service.

dbus-service.py

@@ -159,10 +159,6 @@ usb.trace_enabled = True
 tls.trace_enabled = True
 
 svc = Device()
-try:
-    loop.run()
-finally:
-    reboot()
-    raise
+loop.run()
 
 print("Normal exit")

proto9x/init.py

@@ -1,16 +1,33 @@
 
+import atexit
+
 from proto9x.usb import usb
 from proto9x.tls import tls
 from proto9x.sensor import sensor
+from proto9x.sensor import reboot
 from proto9x.flash import read_tls_flash
-from usb import core as usb_core
 
+def close():
+    if usb.dev is not None:
+        # Send the reboot command before closing the device.
+        # Without it the sensor seems to keep creating new TLS sessions and eventually runs out of memory.
+        # The reboot command may fail if we're shutting down because the device is already gone.
+        try:
+            reboot()
+        finally:
+            usb.close()
 
 def open():
     usb.open()
     usb.send_init()
+    # We must register atexit only after we opened usb device, 
+    # so that our handler is called before pyusb's one and we can still talk to the device
+    atexit.register(close)
 
     tls.parseTlsFlash(read_tls_flash())
     tls.open()
 
     sensor.open()
+
+
+

proto9x/usb.py

@@ -39,6 +39,14 @@ class Usb():
         self.thread.daemon = True
         self.thread.start()
 
+    def close(self):
+        if self.dev is not None:
+            try:
+                self.dev.reset()
+                self.dev = None
+            finally:
+                self.thread.join()
+
     def usb_dev(self):
         return self.dev
 

prototype.py

@@ -1,4 +1,3 @@
-
 from proto9x.tls import tls
 from proto9x.usb import usb
 from proto9x.db import db
@@ -80,17 +79,3 @@ def enroll(sid, finger):
 
     print('Created a finger record with dbid %d' % recid)
 
-# can't use atexit as it conflicts with atexit installed by libusb
-class Blah:
-    def __init__(self):
-        self.tls=tls
-
-    def __del__(self):
-        if usb.dev is not None:
-            print('Rebooting device...')
-            try:
-                reboot()
-            except:
-                pass
-
-blah=Blah()