CyanogenMod Updates and the firewall

Screenshot of the Update Tool
Screenshot of the Update Tool

I’m running CyanogenMod on my phone and I have the firewall AFWall+ installed.

Screenshot of the firewall with important rules
Screenshot of the firewall with important rules

To update the list of available updates the application CM Updater need to be able to connect to the internet. It will contact a website from within the google empire and ask for available images.

In order to download a new image the application Media Storage, Download Manager, Downloads needs internet access, as this app is in charge of downloading the actual image file.

To be remembered.

JavaDoc Cheat Sheet

  • The first sentence of each doc comment should be a summary sentence
  • Write the description to be implementation-independent, but specifying such dependencies where necessary. (what is required, what is allowed)
  • wrap keywords in <code>...</code>

typical meta annotations

  • @author is not critical, because it is not included when generating the API specification
  • @version SCCS string "%I%, %G%", which converts to something like “ 1.39, 02/28/97” (mm/dd/yy) when the file is checked out of SCCS
  • @since specify the product version when the Java name was added to the API specification (if different from the implementation)

typical method definition

  • @param parameter-name description
    • followed by the name (not data type) of the parameter, followed by a description of the parameter
    • the first noun in the description is the data type
  • @return description
    • omit for methods that return void and for constructors
    • include it for all other methods, even if its content is entirely redundant with the method description
  • @throws class-name description should be included for any checked exceptions (previously, it was @exception)

additional annotations

  • {@value package.class#field}
    • when {@value} is used (without any argument) in the doc comment of a static field, it displays the value of that constant: The value of this constant is {@value}.
    • otherwise it displays the value of the specified constant: Evaluates the script starting with {@value #SCRIPT_START}.
  • {@code text}
    • Equivalent to <code>{@literal}</code>.

linking

  • @see reference
    • Adds a "See Also" heading
    • reference is a string: Adds a text entry for string. No link is generated. The string is a book or other reference to information not available by URL.
    • reference is an <a href="URL#value">label</a>: Adds a link as defined by URL#value. The URL#value is a relative or absolute URL.
    • reference is an package.class#member label: Adds a link (with optional visible text label) that points to the documentation for the specified name in the Java Language that is referenced.
  • {@link package.class#member label}
    • in-line link with visible text label that points to the documentation for the specified package, class or member name of a referenced class
    • not necessary to add links for all API names in a doc comment
  • @serial (or @serialField or @serialData) for interoperability with alternative implementations of a Serializable class and to document class evolution

deprecation

  • @deprecated deprecated-text
    • the first sentence should at least tell the user when the API was deprecated and what to use as a replacement
    • a {@link} tag should be included that points to the replacement method

example

/**
 * The Class CombineArchive to create/read/manipulate/store etc.
 * CombineArchives.
 * <p>
 * We directly operate on the ZIP file, which will be kept open. Therefore, do
 * not forget to finally close the CombineArchive when you're finished.
 * 
 * @see <a href="https://sems.uni-rostock.de/projects/combinearchive/">
 *      sems.uni-rostock.de/projects/combinearchive</a>
 * @author martin scharm
 */
public class CombineArchive
    extends MetaDataHolder
    implements Closeable
{
    /* ... */

    /**
     * Gets the the first main entry of this archive, if defined. As of RC2 of the spec there may be more than one main entry, so you should use {@link #getMainEntries()} instead.
     * 
     * @return the first main entry, or <code>null</code> if there is no main entry
     * @deprecated as of version 0.8.2, replaced by {@link #getMainEntries()}
     */
    public ArchiveEntry getMainEntry ()
    {
        if (mainEntries == null)
            return null;
        return mainEntries.size () > 0 ? mainEntries.get (0) : null;
    }
    
    /**
     * Gets the main entries as defined in the archive.
     *
     * @return the main entries in this archive
     */
    public List<ArchiveEntry> getMainEntries ()
    {
        return mainEntries;
    }

    /**
     * Replace the file associated with a certain entry while keeping the meta
     * data.
     * 
     * @param toInsert
     *          the new file to insert
     * @param oldEntry
     *          the old entry whose file should be replaced
     * @return the new entry
     * @throws IOException If an input or output exception occurred
     */
    public ArchiveEntry replaceFile (File toInsert, ArchiveEntry oldEntry) throws IOException
    {
        addEntry (toInsert, oldEntry.getFilePath (), oldEntry.getFormat (), false);
        entries.put (oldEntry.getFilePath (), oldEntry);
        return oldEntry;
    }
}

References

Block URLs on phone using AdAway

List of hosts file resources for AdAway
List of hosts file resources for AdAway

Using AdAway on your Android phones it is very easy to block a set of URLs.

AdAway (available from F-Droid, source from GitHub) is an ad-blocker. The application basically maintains a list of resources containing lists to ad-servers, see figure for example, e.g.:

# dest ip   url
127.0.0.1   some.ad.server.com

This entry will redirect all traffic meant for some.ad.server.com to the server 127.0.0.1, which is your localhost. Entries from different resources are merged. Thus, all requests to typical ad-servers will fail → annoying advertisements won’t be delivered. It’s quite powerful and gives impressive results. However, I didn’t want to talk about ad-stuff. The cool thing is

AdAway allows for extensions with own hosts files!

You can simply add another link to a file containing further host entries. I created my own AdAway file, uploaded it to https://stuff.lesscomplex.org/adaway.txt and added it to AdAway, as you can see in the figure. The current version contains a few entries for:

  • facebook/yahoo/etc: I’m not using facebook or stuff, all these request shouldn’t leave my phone
  • captive portal detection: To detect captive portals the phone downloads a few bytes from a google server and checks if it is able to access the real internet or just a captive portal
  • swift key: I’m using swift key, but do not want it to communicate to the internet. Thus, I’m blocking a few URLs that swiftkey wants to talk to. As I’m already using a firewall this just adds another layer of privacy.

Feel free to use my “extension”, but I expect it to change over time. :)

Shortcomings

This method only works if applications load contents from URLs. As soon as the IPs are hard-coded the hosts file

Disable shutter sound on Cyanogenmod 12

Everyone knows that annoying shutter sound of the camera app on Android phones. It’s against the law to sell android phones which do not make sounds when taking pictures. And in general, it is a good feature as it improves other people privacies.

However, I still want to get rid of the sound. It’s a bit tricky, but having a rooted phone (with e.g. CyanogenMod) it’s very easy: Just delete the sound file /system/media/audio/ui/camera_click.ogg! :)

For the lazy: Get a root shell (eg. ssh or adb) and execute the following:

mount -o remount,rw /system
mv /system/media/audio/ui/camera_click.ogg /system/media/audio/ui/camera_click.ogg.backup
mv /system/media/audio/ui/camera_focus.ogg /system/media/audio/ui/camera_focus.ogg.backup
mount -o remount,ro /system

Problem solved.

Kile menu bar hides entries

Figure 1: Kile -- the menu as expected
Figure 1: Kile -- the menu as expected

Kile, KDE’s Integrated LaTeX Environment, has a weird bug: Every time I update something in the UI it recreates its config file and I loose some menu options, such as Settings -> Configure Kile where you used to configure your preferences..

In Figure 1 you can see the menu as expected. There are some entries to Configure Kile, t0 Configure Toolbars, to Configure Shortcuts and to switch to Full Screen Mode, etc. However, as soon as I update certain things in the user interface (UI), eg. if I add a new action icon to the toolbar to quickly get the \textbf{} environment for bold fonts, these entries get lost. In those cases Kile won’t be configureable anymore. The resulting toolbar is shown in Figure 2. You see, the number of entries significantly decreased..

Figure 2: Kile -- the unexpected menu
Figure 2: Kile -- the unexpected menu

However, I just discovered the reason: Kile in these cases rewrites its config in an unexpected manner… If you have a look at the configuration stored in ~/.kde/share/apps/kile/kileui.rc you’ll find an XML subtree such as:

...
<Menu noMerge="1" name="settings">
	<text>&amp;Settings</text>
	<Action name="Mode"/>
	<Separator/>
	<Action name="settings_perform_check"/>
	<Separator/>
	<Action append="show_merge" name="StructureView"/>
	<Action append="show_merge" name="MessageView"/>
</Menu>
...

No idea where it comes from, but the 1 in noMerge prevents the default menu entries to be merged into the minimal set of entries defined in that snippet. However, now that we know what’s wrong we can easily fix it! Just replace the 1 with a 0 and restart Kile. You might want to do the same for all other menus to discover that you’ve also been missing some entries in the Help menu ;-)

Food equivalents in Social Media

I’ve just been listening to a podcast from DRadio Wissen: Hörsaal (German podcast streaming lectures). I particularly like the podcast of DRadio. This time the lecture was held by Fabian Hemmert, a German design researcher, who was talking about the smartphones’ future. Quite interesting thought in there, but what I actually wanted to jot down was his comparison between food and social media. He tried to find food equivalents in media:

The equivalent of Fat is Fiction!

Invented/fictional things – easy to consume, but not a good base. And too much of it and you’ll often have unnecessary ballast at the end of the day.

The equivalent of Sugar is Approbation!

Everyone likes to hear approvals and confirmation, it’s music to your ears. But too much of it is also unhealthy.

The equivalent of Protein is Truth!

Not too easy to digest, but an important thing to base on.

We are very short on Attention

He also notes that attention is the scarcest resource. Everyone wants us to pay attention and we want everyone to pay attention..

I kind of like the idea! Any other equivalences you can think of?

Tunneling TinyTinyRSS traffic through a Proxy

TT-RSS screenshot
Screenshot of TinyTinyRSS

TinyTinyRSS (TT-RSS) is something that the Google reader always wanted and Feedly still wants to be. Just better! :)

TT-RSS is a free and open source feed aggregator, which can be deployed to your own machine. For example, my instance is running on a cubieboard in my living room. Thus, I’m independent of any company and their plans with my data :)

However, I don’t want to advertise TT-RSS too much, but I want to tell you how to fetch your feeds through a proxy, such as polipo or squid.

Configuring TT-RSS to use a Proxy

It’s apparently undocumented, but looking into the code it turns out that feeds are fetched using cURL:

$ grep -rn PROXY *
include/functions2.php:2257:            if (defined('_CURL_HTTP_PROXY')) {
include/functions2.php:2258:                    curl_setopt($curl, CURLOPT_PROXY, _CURL_HTTP_PROXY);
include/functions.php:389:                      if (defined('_CURL_HTTP_PROXY')) {
include/functions.php:390:                              curl_setopt($ch, CURLOPT_PROXY, _CURL_HTTP_PROXY);
plugins/af_unburn/init.php:41:                          if (defined('_CURL_HTTP_PROXY')) {
plugins/af_unburn/init.php:42:                                  curl_setopt($ch, CURLOPT_PROXY, _CURL_HTTP_PROXY);

And as you can see, the code already supports the usage of a proxy: if (defined('_CURL_HTTP_PROXY')).

I think that might be very interesting to many of you guys and I’ve no idea why it is not documented. However, you can simply define the variable _CURL_HTTP_PROXY in your config.php file. For example, to use a proxy at host 127.0.0.1 listening at port 8123 add the following:

define ('_CURL_HTTP_PROXY', '127.0.0.1:8123');

Now, the TT-RSS traffic will go through the proxy at :8123, which might tunnel everything through, e.g., TOR. Thus, the location of your living room will not be disclosed :)

BONUS: Cache all the Images in Feeds

By default, TT-RSS will not cache the images in feeds. That means, if there is an image in an article, you will be redirected to load the image from a foreign server. That’s obviously something I’d like to avoid, especially because there are plenty of ads or tracking pixels which shouldn’t know about my habits and surf times. But there is an alternative: TT-RSS is able to cache images. It will download the images to your server and deliver the cached versions instead of forwarding you to somewhere else.

Unfortunately, that is not the default. If you want that functionality you need to configure every single feed (Edit FeedOptionsCache images locally). And you must not forget to repeat that procedure for every new feed that will be added in 15+ months…

To avoid that you can simply open the database that TT-RSS uses (e.g. using phpMyAdmin), go to the table ttrss_feeds and modify the default value of the column cache_images from 0 to 1. If that is done, the images of every newly added feed will be cached by default.

If you’re too lazy to manually update the feeds that are already there you can simply run the following SQL query:

UPDATE `ttrss_feeds` SET `cache_images`=1 WHERE 1

Air Pollution makes Babies skinnier

Rich et. al. 2015
Differences in Birth Weight Associated with the 2008 Beijing Olympic Air Pollution Reduction: Results from a Natural Experiment

China radically reduced the air pollution in preparation of the Olympics in 2008 in Beijing. The authors of the publication Differences in Birth Weight Associated with the 2008 Beijing Olympic Air Pollution Reduction: Results from a Natural Experiment [Rich2015a] studied its affect on the weights of newborns. They evaluated how specific months of pregnancy with less air pollution correlate to the birth weights, compared to pregnancies during the same dates in 2007 or 2009. The records were created and maintained by the Beijing Obstetrics and Gynecology Hospital and for the study they just included singleton live births of infants who were 28 completed weeks of gestation or greater in one of four adjacent Beijing districts at the time of birth, which is a sample size of 140,298.

And indeed, they found a correlation:

Babies with their 8th month of pregnancy during the 2008 Olympics were, on average, 23g larger

Interestingly, there was apparently no correlation for months 1-7 of pregnancy!?

References

Organic Plastic

I guess I do not need to tell you anything about the problems with plastics. There is too much of our durable and water-insoluble waste, which is resistant to most natural processes of degradation. To increase our awareness of the amount of plastic we produce in our daily routines we tried to abstain from producing plastic waste during the last Lent. Wasn’t that easy, as you can probably imagine.

As soon as you try to avoid plastic it seems like everything is made of these organic polymers. I’m not talking about the plastic bags that you receive in supermarkets en passant, or the wrappings around frozen pizzas – those are luxuries and almost easy to avoid. But you will have a hard time to get cheese and meat, as they are almost always wrapped in plastic. Milk is then only available from bottles (significantly increasing the weight of your bag); fruits and vegetables are difficult to get – especially organic food: sellers seem to make sure organic food isn’t mixed with non-organic food and therefore apples, for instance, are neatly wrapped in plastic, often just four at a time. I think avoiding plastic is a superset of avoiding supermarkets, as there is almost nothing plastic-free you can buy at supermarkets. Thus, local marketplaces are the last resort. There you can bring own vessels to get them filled by the sellers.

However, that was just the easy part. For some things we did not find a good solution and we simply had to abstain from them or we needed to cheat (which really made us feel bad!):

  • Do you know these tiny plastic things that help you open wine bottles? -> Go for other brands with a screw-cap, for example.
  • Do you know Nutella? -> cap is plastic.
  • All the bathroom stuff. Soap or shower gel for example. You probably need to create your own brands.
  • Handkerchiefs? They always come in plastic wrappings. Only alternatives are these old-fashioned cotton made handkerchiefs. Not very hygienic in my eyes..
  • Same for toilet paper: always in plastic wrappings. I do not have a solution..
  • No IKEA, no Amazon, no non-local stuff in general.

Ah, and did i say no take-away? It is not allowed to go and get some Chinese food or a kebab, as that usually involves buying plastic. So… yes.. it’s been a hard time.

All the more I am happy that this issues already arrived at the higher layers and there are efforts to produce organic plastic, which is bio-degradable and made from renewable resources, such as starch, lignocellulose, or polylactic acid. For example, bottles from organic materials, some supermarkets already offer organic bags, and quite a bit of research is going on, e.g. the Fraunhofer Institute for Applied Polymer Research develops organic based foils and coatings that realise sophisticated barriers.

However, the bridge from the lab to the industry is of course challenging. We put high requirements on our products, especially in case of groceries. We do not want to see chemicals from the wrappings passing over to our food and, the other way around, flavours of our food shouldn’t leave the wrappings (just think of coffee!). There are other but equally high requirements for products in medicine and cosmetics.

Read more

Those who sleep longer die earlier.

Neurology-2015-Leng-1072-9.pdf
Sleep duration and risk of fatal and nonfatal stroke: A prospective study and meta-analysis

At least the risk for a stroke increases, according to a publication by Leng et al. in Neurology, 2015: Sleep duration and risk of fatal and nonfatal stroke: A prospective study and meta-analysis [Leng2015]. They studied the association between sleep duration and stroke incidence in a British population.

More than 9k study participants were asked about their habits of sleeping, afterwards the authors of the study recorded who of them had a stroke, for about 9 years.
This study showed, that participants who sleep more than 8 hours a day are 46% more likely to get a stroke than those who sleep 6-8 hours:

Those with short sleep had an 18% increased stroke risk (not statistically significant), while long sleep was associated with a 46% increase in stroke risk after adjustment for conventional cardiovascular disease (CVD) risk factors and comorbidities.

It’s not yet clear whether there is a causal connection or just a correlation, but I found that potentially interesting. Is a longer sleep already a sign for a bad health condition? Even worse, is sleep a reason for a stroke?

Also read: Is sleep duration a risk factor for stroke? [Ramos2015]

References