From 04fa59ce1d61681c425a70f8f196438cda2fdb68 Mon Sep 17 00:00:00 2001
From: Viktor Dragomiretskyy <Viktor.Dragomiretskyy@gmail.com>
Date: Sat, 11 Jul 2020 17:03:27 +1200
Subject: [PATCH] Add option to start service on a specific device identified
 by bus number and device address.

---
 dbus_service/dbus-service | 14 +++++++++++---
 validitysensor/init.py    | 10 +++++++---
 validitysensor/usb.py     | 19 +++++++++++++++----
 3 files changed, 33 insertions(+), 10 deletions(-)

diff --git a/dbus_service/dbus-service b/dbus_service/dbus-service
index c2ab89e..55332ec 100755
--- a/dbus_service/dbus-service
+++ b/dbus_service/dbus-service
@@ -1,6 +1,7 @@
 #!/usr/bin/env python3
 
 import argparse
+import re
 import dbus
 import dbus.mainloop.glib
 import dbus.service
@@ -150,15 +151,22 @@ class Device(dbus.service.Object):
 if __name__ == '__main__':
     parser = argparse.ArgumentParser('Open fprintd DBus service')
     parser.add_argument('--debug', help='Enable tracing', action='store_true')
+    parser.add_argument('--devpath', help='USB device path: usb-<busnum>-<address>')
     args = parser.parse_args()
 
     if args.debug:
         logging.basicConfig(level=logging.DEBUG)
+        usb.trace_enabled = True
+        tls.trace_enabled = True
 
-    init.open()
+    if args.devpath is None:
+        init.open()
+    else:
+        z = re.match('^usb-(\d+)-(\d+)$', args.devpath)
+        if not z:
+            parser.error('Option --devpath should look like this: usb-<busnum>-<address>')
 
-    usb.trace_enabled = True
-    tls.trace_enabled = True
+        init.open_devpath(*map(int, z.groups()))
 
     bus = dbus.SystemBus()
 
diff --git a/validitysensor/init.py b/validitysensor/init.py
index 7457f6e..65cb1dc 100644
--- a/validitysensor/init.py
+++ b/validitysensor/init.py
@@ -17,8 +17,7 @@ def close():
         finally:
             usb.close()
 
-def open():
-    usb.open()
+def open_common():
     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
@@ -29,5 +28,10 @@ def open():
 
     sensor.open()
 
+def open():
+    usb.open()
+    open_common()
 
-
+def open_devpath(busnum, address):
+    usb.open_devpath(busnum, address)
+    open_common()
diff --git a/validitysensor/usb.py b/validitysensor/usb.py
index 91c573d..db80f5d 100644
--- a/validitysensor/usb.py
+++ b/validitysensor/usb.py
@@ -15,9 +15,6 @@ supported_devices=[
 ]
 
 
-def custom_match(d):
-    return (d.idVendor, d.idProduct) in supported_devices
-
 class Usb():
     def __init__(self):
         self.interrupt_cb = None
@@ -29,11 +26,25 @@ class Usb():
         if vendor is not None and product is not None:
             dev = ucore.find(idVendor=vendor, idProduct=product)
         else:
-            dev = ucore.find(custom_match=custom_match)
+            def match(d):
+                return (d.idVendor, d.idProduct) in supported_devices
+
+            dev = ucore.find(custom_match=match)
+
+        self.open_dev(dev)
+
+    def open_devpath(self, busnum, address):
+        def match(d):
+            return d.bus == busnum and d.address == address
+            
+        dev = ucore.find(custom_match=match)
 
         self.open_dev(dev)
 
     def open_dev(self, dev):
+        if dev is None:
+            raise Exception('No matching devices found')
+
         self.dev = dev
         self.dev.default_timeout = 15000
         self.thread = Thread(target=lambda: self.int_thread())