Things I learned last week (8)

Android devices

Murphy’s Law adapted for Android development: The udev rules of the computer you are currently using never contain the USB ID of the Android device under test. Probably because the list of Android devices is continuously growing, it is not possible to download a set of rules that stays up to date but, as Google provides a web page containing this list of USB IDs, it is easy to write a XSLT document to process the HTML table:

<!-- generate-rules.xslt -->
<?xml version="1.0" ?>

<xsl:stylesheet version="1.0" xmlns:xsl="http://www.w3.org/1999/XSL/Transform">
  <xsl:output method="text" />
  <xsl:template match="text() | comment()" />
  <xsl:template match="table">
# Generated by generate-rules.xslt
    <xsl:apply-templates />
  </xsl:template>
  <xsl:template match="tr[1]" />
  <xsl:template match="tr">
# <xsl:value-of select="td[1]" />
SUBSYSTEM=="usb", ATTR{idVendor}=="<xsl:value-of select="td[2]" />", MODE="0666", GROUP="plugdev"
  </xsl:template>
</xsl:stylesheet>

The rules file can then be automatically generated, for example in a cron job, with a command like this:

curl https://developer.android.com/tools/device.html | xsltproc --html generate-rules.xslt - >51-android.rules

You probably need to reload udev after this.

Installing CPN Tools under Linux

I recently upgraded CPN Tools to version 3.9.3 and unfortunately this time the instructions for the installation under Linux were missing some steps:

  • Download the JRE for Windows from “https://www.java.com/en/download/manual.jsp” and install it under Wine with “wine jre-7u25-windows-i586.exe”. Install the Linux simulator.
  • After this download the new version of CPN Tools and install with “wine cpntools_3.9.3.exe”
  • Go to the simulator direction (~/.wine/drive_c/Program Files/CPN Tools/cpnsim) and make the right files executable with “chmod 775 cpnmld.x86-linux run.x86-linux”
  • In the CPN Tools directory modify the default.xml file so the “enterss.ogpath” contains “statespacefiles/”

There is 2 background jobs to start before the GUI, first is the simulator. To keep an eye on the log, I run the following script in a console:

<#!/bin/bash

trap 'kill $pid; wait; exit' INT TERM
cd ~/.wine/drive_c/Program Files/CPN Tools/cpnsim
./cpnmld.x86-linux -d 2098 ./run.x86-linux cpnmld.log &
pid=%+
tail -F cpnmld.log

The second background job is the simulator extensions server that can be started with the following command:

java -jar ~/.wine/drive_c/Program Files/CPN Tools/extensions/SimulatorExtensions.jar &

The CPN Tools GUI can finally be started with the following command:

wine ~/.wine/drive_c/Program Files/CPN Tools/cpntools.exe

One thing that does not work is the Save state space report: For some reason the open syscall receives the Windows name of the file (“C:…”) instead of the equivalent Linux name. But the state space queries are working fine, so that’s not really a big issue.

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