correct prefix in .policy

README.md

@@ -14,7 +14,7 @@ will likely work.
 # Running
 
 ```bash
-sudo python3 setup.py install --prefix /usr && sudo key-mapper-gtk -d
+sudo python3 setup.py install && sudo key-mapper-gtk -d
 ```
 
 You can also start it via your applications menu.

data/org.key-mapper.ubuntu.policy

@@ -0,0 +1,19 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<!DOCTYPE policyconfig PUBLIC
+    "-//freedesktop//DTD PolicyKit Policy Configuration 1.0//EN"
+    "http://www.freedesktop.org/standards/PolicyKit/1/policyconfig.dtd"
+>
+<policyconfig>
+    <icon_name>mouse</icon_name>
+    <action id="org.key-mapper">
+        <description>Run Key Mapper as root</description>
+        <message>Authentication is required to discover devices and write configs.</message>
+        <defaults>
+            <allow_any>no</allow_any>
+            <allow_inactive>auth_admin</allow_inactive>
+            <allow_active>auth_admin</allow_active>
+        </defaults>
+        <annotate key="org.freedesktop.policykit.exec.path">{executable}</annotate>
+        <annotate key="org.freedesktop.policykit.exec.allow_gui">true</annotate>
+    </action>
+</policyconfig>

setup.py

@@ -19,9 +19,38 @@
 # along with key-mapper.  If not, see <https://www.gnu.org/licenses/>.
 
 
+import os
+
 import DistUtilsExtra.auto
 
 
+class Install(DistUtilsExtra.auto.install_auto):
+    def run(self):
+        DistUtilsExtra.auto.install_auto.run(self)
+        self.ensure_polkit_prefix()
+
+    def ensure_polkit_prefix(self):
+        """Make sure the policy file uses the right prefix."""
+        policy_path = os.path.join(
+            self.install_data,
+            'share/polkit-1/actions/org.key-mapper.policy'
+        )
+
+        executable = os.path.join(self.install_data, 'bin/key-mapper-gtk')
+        assert os.path.exists(executable)
+
+        with open(policy_path, 'r') as f:
+            contents = f.read()
+            if not '{executable}':
+                # already done previously
+                return
+
+        with open(policy_path, 'w') as f:
+            f.write(contents.format(
+                executable=executable
+            ))
+
+
 DistUtilsExtra.auto.setup(
     name='key-mapper',
     version='0.1.0',
@@ -31,4 +60,7 @@ DistUtilsExtra.auto.setup(
         ('share/applications/', ['data/key-mapper.desktop']),
         ('share/polkit-1/actions/', ['data/org.key-mapper.policy']),
     ],
+    cmdclass={
+        'install': Install
+    }
 )