Simplify sys-usb udev rules/actions

By using a single matching strategy in the udev rules, we can simplify
this down to one rule and one script for attaching export devices, as
the device paths passed to the script for either storage or printer
devices will be at equivalent depths.

dom0/sys-usb.sls

@@ -32,18 +32,10 @@ sd-rc-local-udev-rules:
     - require:
       - file: sd-rc-local-udev-rules
 
-sd-attach-export-disk:
+sd-attach-export-device:
   file.managed:
-    - name: /usr/local/bin/sd-attach-export-disk
-    - source: salt://sd/sys-usb/sd-attach-export-disk
-    - user: root
-    - group: root
-    - mode: 0555
-
-sd-attach-export-printer:
-  file.managed:
-    - name: /usr/local/bin/sd-attach-export-printer
-    - source: salt://sd/sys-usb/sd-attach-export-printer
+    - name: /usr/local/bin/sd-attach-export-device
+    - source: salt://sd/sys-usb/sd-attach-export-device
     - user: root
     - group: root
     - mode: 0555

sys-usb/99-sd-export-usb.rules

@@ -1,2 +1,6 @@
-ACTION=="add", SUBSYSTEM=="usb", DRIVER=="usb-storage", RUN+="/usr/local/bin/sd-attach-export-disk"
-ACTION=="add", SUBSYSTEM=="usb", ENV{DEVTYPE}=="usb_device", ENV{ID_USB_INTERFACES}=="*:0701??:*", RUN+="/usr/local/bin/sd-attach-export-printer"
+# Class 08 == storage, subclass 06 == SCSI
+# Class 07 == printer, subclass 01 == printer
+# https://www.usb.org/defined-class-codes
+# https://www.usb.org/document-library/mass-storage-class-specification-overview-14
+# https://www.usb.org/document-library/printer-device-class-document-11
+ACTION=="add", SUBSYSTEM=="usb", ENV{DEVTYPE}=="usb_device", ENV{ID_USB_INTERFACES}=="*:0806??:*|*:0701??:*", RUN+="/usr/local/bin/sd-attach-export-device"

sys-usb/sd-attach-export-device

@@ -0,0 +1,6 @@
+#!/bin/bash
+
+# udev action for attaching USB export devices to sd-export-usb
+
+QDEVNAME="$(basename $DEVPATH)"
+echo sys-usb "$QDEVNAME" | qrexec-client-vm sd-export-usb qubes.USBAttach

tests/test_sys_usb.py

@@ -11,8 +11,7 @@ def setUp(self):
 
     def test_files_are_properly_copied(self):
         self.assertTrue(self._fileExists("/etc/udev/rules.d/99-sd-export-usb.rules"))
-        self.assertTrue(self._fileExists("/usr/local/bin/sd-attach-export-disk"))
-        self.assertTrue(self._fileExists("/usr/local/bin/sd-attach-export-printer"))
+        self.assertTrue(self._fileExists("/usr/local/bin/sd-attach-export-device"))
 
 
 def load_tests(loader, tests, pattern):