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Adding GTK+ 3 support and building CoreGTK using GObject Introspection

May 3rd, 2015 No comments

It has been a while since I made any mention of my side project CoreGTK. I’m sure many people can relate that with life generally being very busy it is often hard to find time to work on hobby projects like this. Thankfully while that certainly has slowed the pace of development it hasn’t stopped it outright and now I am just about ready to show off the next update for CoreGTK.

First off thank you to everyone who took a look at the previous release. I received quite a few nice comments as well as some excellent feedback and hope to address quite a bit of that here. The feedback plus my own ideas of where I wanted to take the project defined the goal for the next release that I am currently working toward.

Goals for this release:

  • Move from GTK+ 2 to GTK+ 3
  • Prefer the use of glib data types over boxed OpenStep/Cocoa objects (i.e. gint vs NSNumber)
  • Base code generation on GObject Introspection instead of a mix of automated source parsing and manual correction

In order to explain the rationale behind these goals I figured I would address each point in more detail.

Move from GTK+ 2 to GTK+ 3

This one was pretty much a no-brainer. GTK+ 3 is now the current supported widget toolkit and has been since February 2011. Previously my choice to use GTK+ 2 was simply due to the fact that I wanted to make it as cross-platform as possible and at the time of release GTK+ 3 was not supported on Windows. Now that this has changed it only makes sense to continue forward using the current standard.

Additionally this allows for a natural break in compatibility with the previous release of CoreGTK. What that means for the end user is that I currently don’t have any plans on going back and applying any of these new ideas/changes to the old GTK+ 2 version of the code base, instead focusing my time and effort on GTK+ 3.

Prefer the use of glib data types over boxed OpenStep/Cocoa objects (i.e. gint vs NSNumber)

When originally designing CoreGTK I decided to put a stake in the ground and simply always favour OpenStep/Cocoa objects where possible. The hope was that this would allow for easier integration with existing Objective-C code bases. Unfortunately good intentions don’t always work out in the best way. One of the major pieces of feedback I got was to take a less strict approach on this and drop the use of some classes where it makes sense. Specifically keep using NSString instead of C strings but stop using NSNumber in place of primitives like gint (which itself is really just a C int). The net result of this change is far less boilerplate code and faster performance.

So instead of writing this:

/* Sets the border width of the window */
[window setBorderWidth: [NSNumber numberWithInt:10]];

you can now simply write this:

/* Sets the border width of the window */
[window setBorderWidth: 10];

Base code generation on GObject Introspection instead of a mix of automated source parsing and manual correction

The previous version of CoreGTK was, shall we say, hand crafted. I had written some code to parse header files and generate a basic structure for the Objective-C output but there was still quite a bit of manual work involved to clean up this output and make it what it was. Other than the significant investment in time required to make this happen it was also prone to errors and would require starting back at square one with every new release of GTK+. This time around the output is generated using GObject Introspection, specifically by parsing the generated GIR file for that library. Currently, and I must stress that there is still quite a bit of room for improvement, this allows me to generate CoreGTK bindings from scratch within an hour or so. With some of the final touches I have in mind the time required for this should hopefully be down to minutes (the auto-generation itself only takes seconds but it isn’t 100% yet). Better still once this process is perfected it should be relatively easy to adapt it to support other GObject Introspection supported libraries like Pango, Gdk, GStreamer, etc.

So where is this new release?

I am getting closer to showing off this new code but first I have to do a bit of cleanup on it. This hopefully won’t take too much longer and to show you how close I am here is a screenshot of CoreGTK running using GTK+ 3.

coregtk-3

This post originally appeared on my personal website here.




I am currently running a variety of distributions, primarily Linux Mint 17.
Previously I was running KDE 4.3.3 on top of Fedora 11 (for the first experiment) and KDE 4.6.5 on top of Gentoo (for the second experiment).

How to easily forward Firefox (PC & Android) traffic through an SSH tunnel

March 29th, 2015 No comments

Say you are travelling, or are at a neighbourhood coffee shop, using whatever unsecured WiFi network they make available. You could either:

  1. trust that no one is sniffing your web traffic, capturing passwords, e-mails, IMs, etc.
  2. trust that no one is using more sophisticated methods to trick you into thinking that you are secure (i.e. man in the middle attack)
  3. route your Internet traffic through a secure tunnel to your home PC before going out onto the web, protecting you from everyone at your current location

which would you choose?

VPNs and SSH tunnels are actually a relatively easy means for you to be more secure while browsing the Internet from potentially dangerous locations.

Making use of an SSH tunnel on your PC

There are many, many different ways for you to do this but I find using a Linux PC that is running on your home network to be the easiest.

Step 1: Install SSH Server

Configure your home Linux PC. Install ssh (and sshd if it is separate). If you are using Ubuntu this is as easy as running the following command: sudo apt-get install ssh

Step 2: Make it easy to connect

Sign up for a free dynamic DNS service like DynDNS or No-IP so that you know of a web address that always points to your home Internet connection. To do this follow the instructions at the service you choose.

Step 3: Connect to tunnel

On your laptop (that you have taken with you to the hotel or coffee shop) connect to your home PC’s ssh server. If you are on Windows you will need to get a program like PuTTY. See their documentation on how to forward ports. On Linux you can simply use the ssh command. The goal is to forward a dynamic port to the remote ssh server. For instance if you are using a Linux laptop and ssh then the command would look something like: ssh -D [dynamic port] [user]@[home server] -p [external port number – if not 22]. An example of one would be ssh -D 4096 user@example.com -p 4000

Step 4: Configure browser to use SSH tunnel proxy

In your browser open the networking options window. This will allow you to tell the browser to forward all of its traffic to a proxy, which in this case, will be our dynamic port that we set up in step 3. Here is an example of my configuration for the example above.
If you don’t feel awesome enough doing the above graphically you can also browse to “about:config” (without quotes) and set the following values:

  • network.proxy.proxy_over_tls
    • true
  • network.proxy.socks
    • Change to “127.0.0.1” with no quotes
  • network.proxy.socks_port
    • Change to the SSH Tunnel Local Port set above (4096)
  • network.proxy.socks_remote_dns
    • Change to true
    • Note: you cannot actually set this setting graphically but it is highly recommended to configure this as well!
  • network.proxy.socks_version
    • Change to 5
  • network.proxy.type
      Change to 1

Step 5: Test and use

Browse normally – you are now browsing the Internet by routing all of your traffic (in Firefox) securely through your home PC. Note that this doesn’t actually make web browsing any more secure beyond protecting you from people in your immediate vicinity (i.e. connected to the same insecure WiFi network).


What about Android?

Just like the PC you can also do it on Android even without root access. Please note that while I’m sure there are a few ways to accomplish this, the following is just one way that has worked for me. I’m also assuming that you already have an SSH server to tunnel your traffic through.

Step 1: Install SSH Tunnel

The first thing you’ll want to do is install an application that will actually create the SSH tunnel for you. One such application is the aptly named SSH Tunnel which can be found on the Google Play Store here.

Step 2: Configure SSH Tunnel

Next you’ll want to launch the application and configure it.

  • Set the Host address (either a real domain name, dynamic DNS redirector or IP address of your SSH server) and port to connect on.
  • You’ll also want to configure the User and Password / Passphrase.
  • Check the box that says Use socks proxy.
  • Configure the Local Port that you’ll connect to your tunnel on (perhaps 1984 for the paranoid?)
  • I would recommend checking Auto Reconnect as well, especially if you are on a really poor WiFi connection like at a hotel or something.
  • Finally check Enable DNS Proxy.

Step 3: Connect SSH Tunnel

To start the SSH tunnel simply check the box that says Tunnel Switch.

Step 4: Install Firefox

While you may have a preference for Google Chrome, Firefox is the browser I’m going to recommend setting up the tunnel with. Additionally this way if you do normally use Chrome you can simply leave Firefox configured to always use the SSH tunnel and only switch to it when you want the additional privacy. Firefox can be found on the Google Play store here.

Step 5: Configure Firefox to use SSH Tunnel

In order to make Firefox connect via the SSH tunnel you’ll need to modify some settings. Once you are finished the browser will only work if the SSH tunnel is connected.

  • In the Firefox address bar browse to “about:config” with no quotes.
  • In the page that loads search and modify the following values:
    • network.proxy.proxy_over_tls
      • true
    • network.proxy.socks
      • Change to “127.0.0.1” with no quotes
    • network.proxy.socks_port
      • Change to the SSH Tunnel Local Port set above (1984?)
    • network.proxy.socks_remote_dns
      • Change to true
    • network.proxy.socks_version
      • Change to 5
    • network.proxy.type
        Change to 1

Step 6: Test and browse normally

Now that you have configured the above you should be able to browse via the tunnel. How can you check if it is working? Simply turn off the SSH Tunnel and try browsing – you should get an error message. Or if you are on a different WiFi you could try using a service to find your IP address and make sure it is different from where you are. For example if you configured Firefox to work via the SSH tunnel but left Chrome as is then visiting a site like http://www.whatismyip.com/ should show different information in each browser.

This post is a complication of two posts which originally appeared on my personal website here.




I am currently running a variety of distributions, primarily Linux Mint 17.
Previously I was running KDE 4.3.3 on top of Fedora 11 (for the first experiment) and KDE 4.6.5 on top of Gentoo (for the second experiment).

Applying updates to Docker and the Plex container

December 7th, 2014 No comments

In my last post, I discussed several Docker containers that I’m using for my home media streaming solution. Since then, Plex Media Server has updated to 0.9.11.4 for non-Plex Pass users, and there’s another update if you happen to pay for a subscription. As the Docker container I used (timhaak/plex) was version 0.9.11.1 at the time, I figured I’d take the opportunity to describe how to

  • update Docker itself to the latest version
  • run a shell inside the container as another process, to review configuration and run commands directly
  • update Plex to the latest version, and describe how not to do this
  • perform leet hax: commit the container to your local system, manually update the package, and re-commit and run Plex

Updating Docker

I alluded to the latest version of Docker having features that make it easier to troubleshoot inside containers. Switching to the latest version was pretty simple: following the instructions to add the Docker repository to my system, then running

sudo apt-get update
sudo apt-get install lxc-docker

upgraded Docker to version 1.3.1 without any trouble or need to manually uninstall the previous Ubuntu package.

Run a shell using docker exec

Let’s take a look inside the plex container. Using the following command will start a bash process so that we can review the filesystem on the container:

docker exec -t -i plex /bin/bash

You will be dropped into a root prompt inside the plex container. Check out the filesystem: there will be a /config and a /data directory pointing to “real” filesystem locations. You can also use ps aux to review the running processes, or even netstat -anp to see active connections and their associated programs. To exit the shell, use Ctrl+C – but the container will still be running when you use docker ps -a from the host system.

Updating Plex in-place: My failed attempt

Different Docker containers will have different methods of performing software updates. In this case, looking at the Dockerfile for timhaak/plex, we see that a separate repository was added for the Plex package – so we should be able to confirm that the latest version is available. This also means that if you destroy your existing container, pull the latest image, then launch a new copy, the latest version of Plex will be installed (generally good practice.)

But wait – the upstream repository at http://shell.ninthgate.se/packages/debian/pool/main/p/plexmediaserver/ does contain the latest .deb packages for Plex, so can’t we just run an apt-get update && apt-get upgrade?

Well, not exactly. If you do this, the initial process used to run Plex Media Server inside the Docker container (start.sh) gets terminated, and Docker takes down the entire plex container when the initial process terminates. Worse, if you then decide to re-launch things with docker start plex, the new version is incompletely installed (dpkg partial configuration).

So the moral of the story: if you’re trying this at home, the easiest way to upgrade is to recreate your Plex container with the following commands:

docker stop plex

docker rm plex

# The 'pull' process may take a while - it depends on the original repository and any dependencies in the Dockerfile. In this case it has to pull the new version of Plex.
docker pull timhaak/plex

# Customize this command with your config and data directories.
docker run -d -h plex --name="plex" -v /etc/docker/plex:/config -v /mnt/nas:/data -p 32400:32400 timhaak/plex

Once the container is up and running, access http://yourserver:32400/web/ to confirm that Plex Media Server is running. You can check the version number by clicking the gear icon next to your server in the left navigation panel, then selecting Settings.

Hacking the container: commit it and manually update Plex from upstream

If you’re more interested in hacking the current setup, there’s a way to commit your existing Plex image, manually perform the upgrade, and restart the container.

First, make sure the plex container is running (docker start plex) and then commit the container to your local filesystem (replacing username with your preferred username):

docker commit plex username/plex:latest

Then we can stop the container, and start a new instance where bash is the first process:

docker stop plex

docker rm plex

# Replace username with the username you selected above.
docker run -t -i --name="plex" -h plex username/plex:latest /bin/bash

Once inside the new plex container, let’s grab the latest Plex Media Server package and force installation:

curl -O https://downloads.plex.tv/plex-media-server/0.9.11.4.739-a4e710f/plexmediaserver_0.9.11.4.739-a4e710f_amd64.deb

dpkg -i plexmediaserver_0.9.11.4.739-a4e710f_amd64.deb

# When prompted, select Y to install the package maintainer's versions of files. In my instance, this updated the init script as well as the upstream repository.

Now, we can re-commit the image with the new Plex package. Hit Ctrl+D to exit the bash process, then run:

docker commit plex username/plex:latest

docker rm plex

# Customize this command with your config and data directories.
docker run -d -h plex --name="plex" -v /etc/docker/plex:/config -v /mnt/nas:/data -p 32400:32400 username/plex /start.sh

# Commit the image again so it will run start.sh if ever relaunched:
docker commit plex username/plex:latest

You’ll also need to adjust your /etc/init/plex.conf upstart script to point to username/plex.

The downside of this method is now that you’ve forked the original Plex image locally and will have to do this again for updates. But hey, wasn’t playing around with Docker interesting?




I am currently running Ubuntu 14.04 LTS for a home server, with a mix of Windows, OS X and Linux clients for both work and personal use.
I prefer Ubuntu LTS releases without Unity - XFCE is much more my style of desktop interface.
Check out my profile for more information.
Categories: Docker, Jake B, Plex, Ubuntu Tags:

Running a containerized media server with Ubuntu 14.04, Docker, and Plex

November 23rd, 2014 No comments

I recently took it upon myself to rebuild a general-purpose home server – installing a new Intel 530 240GB solid-state drive to replace a “spinning rust” drive, and installing a fresh copy of Ubuntu 14.04 now that 14.04.1 has released and there is much less complaining online.

The “new hotness” that I’d like to discuss has been the use of Docker to containerize various processes. Docker gets a lot of press these days, but the way I see it is a way to ensure that your special snowflake applications and services don’t get the opportunity to conflict with one another. In my setup, I have four containers running:

I like the following things about Docker:

  • Since it’s new, there are a lot of repositories and configuration instructions online for reference.
  • I can make sure that applications like Sonarr/NZBDrone get the right version of Mono that won’t conflict with my base system.
  • As a network administrator, I can ensure that only the necessary ports for a service get forwarded outside the container.
  • If an application state gets messed up, it won’t impact the rest of the system as much – I can destroy and recreate the individual container by itself.

There are some drawbacks though:

  • Because a lot of the images and Dockerfiles out there are community-based, there are some that don’t follow best practices or fall out of an update cycle.
  • Software updates can become trickier if the application is unable to upgrade itself in-place; you may have to pull a new Dockerfile and hope that your existing configuration works with a new image.
  • From a security standpoint, it’s best to verify exactly what an image or Dockerfile does before running it – for example, that it pulls content from official repositories (the docker-plex configuration is guilty of using a third-party repo, for example.)

To get started, on Ubuntu 14.04 you can install a stable version of Docker following these instructions, although the latest version has some additional features like docker exec that make “getting inside” containers to troubleshoot much easier. I was able to get all these containers running properly with the current stable version (1.0.1~dfsg1-0ubuntu1~ubuntu0.14.04.1). Once Docker is installed, you can grab each of the containers above with a combination of docker search and docker pull, then list the downloaded containers with docker images.

There are some quirks to remember. On the first run, you’ll need to docker run most of these containers and provide a hostname, box name, ports to forward and shared directories (known as volumes). On all subsequent runs, you can just use docker start $container_name – but I’ll describe a cheap and easy way of turning that command into an upstart service later. I generally save the start commands as shell scripts in /usr/local/bin/docker-start/*.sh so that I can reference them or adjust them later. The start commands I’ve used look like:

Plex
docker run -d -h plex --name="plex" -v /etc/docker/plex:/config -v /mnt/nas:/data -p 32400:32400 timhaak/plex
SABnzbd+
docker run -d -h sabnzbd --name="sabnzbd" -v /etc/docker/sabnzbd:/config -v /mnt/nas:/data -p 8080:8080 -p 9090:9090 timhaak/sabnzbd
Sonarr
docker run -d -h sonarr --name="sonarr" -v /etc/docker/sonarr:/config -v /mnt/nas:/data -p 8989:8989 tuxeh/sonarr
CouchPotato
docker run -d -h couchpotato --name="couchpotato" -e EDGE=1 -v /etc/docker/couchpotato:/config -v /mnt/nas:/data -v /etc/localtime:/etc/localtime:ro -p 5050:5050 needo/couchpotato
These applications have a “/config” and a “/data” shared volume defined. /data points to “/mnt/nas”, which is a CIFS share to a network attached storage appliance mounted on the host. /config points to a directory structure I created for each application on the host in /etc/docker/$container_name. I generally apply “chmod 777” permissions to each configuration directory until I find out what user ID the container is writing as, then lock it down from there.

For each initial start command, I choose to run the service as a daemon with -d. I also set a hostname with the “-h” parameter, as well as a friendly container name with “–name”; otherwise Docker likes to reference containers with wild adjectives combined with scientists, like “drunk_heisenberg”.

Each of these containers generally has a set of instructions to get up and running, whether it be on Github, the developer’s own site or the Docker Hub. Some, like SABnzbd+, just require that you go to http://yourserverip:8080/ and complete the setup wizard. Plex required an additional set of configuration steps described at the original repository:

  • Once Plex starts up on port 32400, access http://yourserverip:32400/web/ and confirm that the interface loads.
  • Switch back to your host machine, and find the place where the /config directory was mounted (in the example above, it’s /etc/docker/plex). Enter the Library/Application Support/Plex Media Server directory and edit the Preferences.xml file. In the <Preferences> tag, add the following attribute: allowedNetworks=”192.168.1.0/255.255.255.0″ where the IP address range matches that of your home network. In my case, the entire file looked like:

    <?xml version="1.0" encoding="utf-8"?>
    <Preferences MachineIdentifier="(guid)" ProcessedMachineIdentifier="(another_guid)" allowedNetworks="192.168.1.0/255.255.255.0" />

  • Run docker stop plex && docker start plex to restart the container, then load http://yourserverip:32400/web/ again. You should be prompted to accept the EULA and can now add library locations to the server.

Sonarr needed to be updated (from the NZBDrone branding) as well. From the GitHub README, you can enable in-container upgrades:

[C]onfigure Sonarr to use the update script in /etc/service/sonarr/update.sh. This is configured under Settings > (show advanced) > General > Updates > change Mechanism to Script.

To automatically ensure these containers start on reboot, you can either use restart policies (Docker 1.2+) or write an upstart script to start and stop the appropriate container. I’ve modified the example from the Docker website slightly to stop the container as well:

description "SABnzbd Docker container"
author "Jake"
start on filesystem and started docker
stop on runlevel [!2345]
respawn
script
/usr/bin/docker start -a sabnzbd
end script
pre-stop exec /usr/bin/docker stop sabnzbd

Copy this script to /etc/init/sabnzbd.conf; you can then copy it to plex, couchpotato, and sonarr.conf and change the name of the container and title in each. You can then test it by rebooting your system and running “docker ps -a” to ensure that all containers come up cleanly, or running “docker stop $container; service $container start”. If you run into trouble, the upstart logs are in /var/log/upstart/$container_name.conf.

Hopefully this introduction to a media server with Docker containers was thought-provoking; I hope to have further updates down the line for other applications, best practices and how this setup continues to operate in its lifetime.




I am currently running Ubuntu 14.04 LTS for a home server, with a mix of Windows, OS X and Linux clients for both work and personal use.
I prefer Ubuntu LTS releases without Unity - XFCE is much more my style of desktop interface.
Check out my profile for more information.
Categories: Docker, Jake B, Plex, Ubuntu Tags:

Cloud software for a Synology NAS and setting up OwnCloud

November 8th, 2014 No comments

Recently the Kitchener Waterloo Linux Users Group held a couple of presentations on setting up your own personally hosted cloud. With their permission we are pleased to also present it below:

Read more…




I am currently running a variety of distributions, primarily Linux Mint 17.
Previously I was running KDE 4.3.3 on top of Fedora 11 (for the first experiment) and KDE 4.6.5 on top of Gentoo (for the second experiment).

Big distributions, little RAM 7

October 13th, 2014 4 comments

It’s been a while but once again here is the latest instalment of the series of posts where I install the major, full desktop, distributions into a limited hardware machine and report on how they perform. Once again, and like before, I’ve decided to re-run my previous tests this time using the following distributions:

  • Debian 7.6 (GNOME)
  • Elementary OS 0.2 (Luna)
  • Fedora 20 (GNOME)
  • Kubuntu 14.04 (KDE)
  • Linux Mint 17 (Cinnamon)
  • Linux Mint 17 (MATE)
  • Mageia 4.1 (GNOME)
  • Mageia 4.1 (KDE)
  • OpenSUSE 13.1 (GNOME)
  • OpenSUSE 13.1 (KDE)
  • Ubuntu 14.04 (Unity)
  • Xubuntu 14.04 (Xfce)

I also attempted to try and install Fedora 20 (KDE) but it just wouldn’t go.

All of the tests were done within VirtualBox on ‘machines’ with the following specifications:

  • Total RAM: 512MB
  • Hard drive: 8GB
  • CPU type: x86 with PAE/NX
  • Graphics: 3D Acceleration enabled

The tests were all done using VirtualBox 4.3.12, and I did not install VirtualBox tools (although some distributions may have shipped with them). I also left the screen resolution at the default (whatever the distribution chose) and accepted the installation defaults. All tests were run between October 6th, 2014 and October 13th, 2014 so your results may not be identical.

Results

Just as before I have compiled a series of bar graphs to show you how each installation stacks up against one another. Measurements were taken using the free -m command for memory and the df -h command for disk usage.

Like before I have provided the results file as a download so you can see exactly what the numbers were or create your own custom comparisons (see below for link).

Things to know before looking at the graphs

First off if your distribution of choice didn’t appear in the list above its probably not reasonably possible to be installed (i.e. I don’t have hours to compile Gentoo) or I didn’t feel it was mainstream enough (pretty much anything with LXDE). As always feel free to run your own tests and link them in the comments for everyone to see.

First boot memory (RAM) usage

This test was measured on the first startup after finishing a fresh install.

 

All Data Points

All Data Points

RAM

RAM

Buffers/Cache

Buffers/Cache

RAM - Buffers/Cache

RAM – Buffers/Cache

Swap Usage

Swap Usage

RAM - Buffers/Cache + Swap

RAM – Buffers/Cache + Swap

Memory (RAM) usage after updates

This test was performed after all updates were installed and a reboot was performed.

All Data Points

All Data Points

RAM

RAM

Buffers/Cache

Buffers/Cache

RAM - Buffers/Cache

RAM – Buffers/Cache

Swap Usage

Swap Usage

RAM - Buffers/Cache + Swap

RAM – Buffers/Cache + Swap

Memory (RAM) usage change after updates

The net growth or decline in RAM usage after applying all of the updates.

All Data Points

All Data Points

RAM

RAM

Buffers/Cache

Buffers/Cache

RAM - Buffers/Cache

RAM – Buffers/Cache

Swap Usage

Swap Usage

RAM - Buffers/Cache + Swap

RAM – Buffers/Cache + Swap

Install size after updates

The hard drive space used by the distribution after applying all of the updates.

Install Size

Install Size

Conclusion

Once again I will leave the conclusions to you. Source data provided below.

Source Data




I am currently running a variety of distributions, primarily Linux Mint 17.
Previously I was running KDE 4.3.3 on top of Fedora 11 (for the first experiment) and KDE 4.6.5 on top of Gentoo (for the second experiment).

How to set a static IP address on Ubuntu 14.04 server (and others)

September 16th, 2014 No comments

This assumes you want to set a static IP address on the network device eth0.

Open up the interfaces file

sudo nano /etc/network/interfaces

and remove or comment out the line that says

iface eth0 inet dhcp

then add the following lines in its place:

iface eth0 inet static
address [static IP address, i.e. 192.168.1.123]
netmask [i.e. 255.255.255.0]
network [i.e. 192.168.1.0]
broadcast [i.e. 192.168.1.255]
gateway [i.e. 192.168.1.1]
dns-nameservers [i.e. 8.8.8.8]

Save the file and reboot the server. On some systems you may also need to update /etc/resolv.conf and /etc/hosts




I am currently running a variety of distributions, primarily Linux Mint 17.
Previously I was running KDE 4.3.3 on top of Fedora 11 (for the first experiment) and KDE 4.6.5 on top of Gentoo (for the second experiment).

CoreGTK 2.24.0 Released!

August 4th, 2014 No comments

The initial version of CoreGTK, version 2.24.0, has been tagged for release today.

Features include:

  • Targets GTK+ 2.24
  • Support for GtkBuilder
  • Can be used on Linux, Mac and Windows

CoreGTK is an Objective-C language binding for the GTK+ widget toolkit. Like other “core” Objective-C libraries, CoreGTK is designed to be a thin wrapper. CoreGTK is free software, licensed under the GNU LGPL.

You can find more information about the project here and the release itself here.

This post originally appeared on my personal website here.




I am currently running a variety of distributions, primarily Linux Mint 17.
Previously I was running KDE 4.3.3 on top of Fedora 11 (for the first experiment) and KDE 4.6.5 on top of Gentoo (for the second experiment).

Linux alternatives: Mp3tag → EasyTAG

August 4th, 2014 1 comment

A big part of my move from Windows to Linux has been finding replacements for the applications that I had previously used day-to-day that are not available on Linux. For the major applications like my web browser (Firefox), e-mail client (Thunderbird), password manager (KeePass2) this hasn’t been a problem because they are all available on Linux as well. Heck you can even install Microsoft Office with the latest version of wine if you wanted to.

Unfortunately there still remains some programs that will simply not run under Linux. Thankfully this isn’t a huge deal because Linux has plenty of alternative applications that fill in all of the gaps – the trick is just finding the one that is right for you.

Mp3tag is an excellent Windows application that lets you edit the meta data (i.e. artist, album, track, etc.) inside of an MP3, OGG or similar file.

Mp3tag on Windows

Mp3tag on Windows

As a Linux alternative to this excellent program I’ve found a very similar application called EasyTAG that offers at least all of the features that I used to use in Mp3tag (and possibly even more).

EasyTAG on Linux

EasyTAG on Linux

For anyone looking for a good meta data editor I would highly recommend trying this one out.




I am currently running a variety of distributions, primarily Linux Mint 17.
Previously I was running KDE 4.3.3 on top of Fedora 11 (for the first experiment) and KDE 4.6.5 on top of Gentoo (for the second experiment).

How to migrate from TrueCrypt to LUKS file containers

June 15th, 2014 2 comments

With the recent questions surrounding the security of TrueCrypt there has been a big push to move away from that program and switch to alternatives. One such alternative, on Linux anyway, is the Linux Unified Key Setup (or LUKS) which allows you to encrypt disk volumes. This guide will show you how to create encrypted file volumes, just like you could using TrueCrypt.

The Differences

There are a number of major differences between TrueCrypt and LUKS that you may want to be aware of:

  • TrueCrypt supported the concept of hidden volumes, LUKS does not.
  • TrueCrypt allowed you to encrypt a volume in-place, without losing data, LUKS does not.
  • TrueCrypt supports cipher cascades where the data is encrypted using multiple different algorithms just in case one of them is broken at some point in the future. As I understand it this is being talked about for the LUKS 2.0 spec but is currently not a feature.

If you are familiar with the terminology in TrueCrypt you can think of LUKS as offering both full disk encryption and standard file containers.

How to create an encrypted LUKS file container

The following steps borrow heavily from a previous post so you should go read that if you want more details on some of the commands below. Also note that while LUKS offers a lot of options in terms of cipher/digest/key size/etc, this guide will try to keep it simple and just use the defaults.

Step 1: Create a file to house your encrypted volume

The easiest way is to run the following commands which will create the file and then fill it with random noise:

# fallocate -l <size> <file to create>
# dd if=/dev/urandom of=<file to create> bs=1M count=<size>

For example let’s say you wanted a 500MiB file container called MySecrets.img, just run this command:

# fallocate -l 500M MySecrets.img
# dd if=/dev/urandom of=MySecrets.img bs=1M count=500

Here is a handy script that you can use to slightly automate this process:

#!/bin/bash
NUM_ARGS=$#

if [ $NUM_ARGS -ne 2 ] ; then
    echo Wrong number of arguments.
    echo Usage: [size in MiB] [file to create]

else

    SIZE=$1
    FILE=$2

    echo Creating $FILE with a size of ${SIZE}MB

    # create file
    fallocate -l ${SIZE}M $FILE

    #randomize file contents
    dd if=/dev/urandom of=$FILE bs=1M count=$SIZE

fi

Just save the above script to a file, say “create-randomized-file-volume.sh”, mark it as executable and run it like this:

# ./create-randomized-file-volume.sh 500 MySecrets.img

Step 2: Format the file using LUKS + ext4

There are ways to do this in the terminal but for the purpose of this guide I’ll be showing how to do it all within gnome-disk-utility. From the menu in Disks, select Disks -> Attach Disk Image and browse to your newly created file (i.e. MySecrets.img).

Don't forget to uncheck the box!

Don’t forget to uncheck the box!

Be sure to uncheck “Set up read-only loop device”. If you leave this checked you won’t be able to format or write anything to the volume. Select the file and click Attach.

This will attach the file, as if it were a real hard drive, to your computer:

attachedindisksNext we need to format the volume. Press the little button with two gears right below the attached volume and click Format. Make sure you do this for the correct ‘drive’ so that you don’t accidentally format your real hard drive!

Please use a better password

Please use a better password

From this popup you can select the filesystem type and even name the drive. In the image above the settings will format the drive to LUKS and then create an ext4 filesystem within the encrypted LUKS one. Click Format, confirm the action and you’re done. Disks will format the file and even auto-mount it for you. You can now copy files to your mounted virtual drive. When you’re done simply eject the drive like normal or (with the LUKS partition highlighted) press the lock button in Disks. To use that same volume again in the future just re-attach the disk image using the steps above, enter your password to unlock the encrypted partition and you’re all set.

But I don’t even trust TrueCrypt enough to unlock my already encrypted files!

If you’re just using TrueCrypt to open an existing file container so that you can copy your files out of there and into your newly created LUKS container I think you’ll be OK. That said there is a way for you to still use your existing TrueCrypt file containers without actually using the TrueCrypt application.

First install an application called tc-play. This program works with the TrueCrypt format but doesn’t share any of its code. To install it simply run:

# sudo apt-get install tcplay

Next we need to mount your existing TrueCrypt file container. For the sake of this example we’ll assume your file container is called TOPSECRET.tc.

We need to use a loop device but before doing that we need to first find a free one. Running the following command

# sudo losetup -f

should return the first free loop device. For example it may print out

/dev/loop0

Next you want to associate the loop device with your TrueCrypt file container. You can do this by running the following command (sub in your loop device if it differs from mine):

# sudo losetup /dev/loop0 TOPSECRET.tc

Now that our loop device is associated we need to actually unlock the TrueCrypt container:

# sudo tcplay -m TOPSECRET.tc -d /dev/loop0

Finally we need to mount the unlocked TrueCrypt container to a directory so we can actually use it. Let’s say you wanted to mount the TrueCrypt container to a folder in the current directory called SecretStuff:

# sudo mount -o nosuid,uid=1000,gid=100 /dev/mapper/TOPSECRET.tc SecretStuff/

Note that you should swap your own uid and gid in the above command if they aren’t 1000 and 100 respectively. You should now be able to view your TrueCrypt files in your SecretStuff directory. For completeness sake here is how you unmount and re-lock the same TrueCrypt file container when you are done:

# sudo umount SecretStuff/
# sudo dmsetup remove TOPSECRET.tc
# sudo losetup -d /dev/loop0

This post originally appeared on my personal website here.




I am currently running a variety of distributions, primarily Linux Mint 17.
Previously I was running KDE 4.3.3 on top of Fedora 11 (for the first experiment) and KDE 4.6.5 on top of Gentoo (for the second experiment).

Create a virtual hard drive volume within a file in Linux

June 15th, 2014 5 comments

If you are not familiar with the concept of virtual hard drive volumes, sometimes called file containers, they are basically regular looking files that can be used by your computer as if they were real hard drives. So for example you could have a file called MyDrive.img on your computer and with a few quick actions it would appear as though you had just plugged in an external USB stick or hard drive into your computer. It acts just like a normal, physical, drive but whenever you copy anything to that location the copied files are actually being written to the MyDrive.img file behind the scenes. This is not unlike the dmg files you would find on a Mac or even something akin to TrueCrypt file containers.

Why would I want this?

There are a number of reasons why you may be interested in creating virtual volumes. From adding additional swap space to your computer (i.e. something similar to a page file on Windows without needing to create a new hard drive partition) to creating portable virtual disk drives to back up files to, or even just doing it because this is Linux and it’s kind of a neat thing to do.

What are the steps to creating a file container?

The process seems a bit strange but it’s actually really straight forward.

  1. Create a new file to hold the virtual drive volume
      (Optional) Initialize it by filling it with data
  2. Format the volume
  3. Mount the volume and use it

Create a new file to hold the virtual drive volume

There are probably a million different ways to do this but I think the most simple way is to run the following command from a terminal:

fallocate -l <size> <file to create>

So let’s say you wanted to create a virtual volume in a file called MyDrive.img in the current directory with a size of 500MiB. You would simply run the following command:

fallocate -l 500M MyDrive.img

You may notice that this command finishes almost instantly. That’s because while the system created a 500MiB file it didn’t actually write 500MiB worth of data to the file.

This is where the optional step of ‘initializing’ the file comes into play. To be clear you do not need to do this step at all but it can be good practice if you want to clean out the contents of the allocated space. For instance if you wanted to prevent someone from easily noticing when you write data to that file you may pre-fill the space with random data to make it more difficult to see or you may simply want to zero out that part of the hard drive first.

Anyway if you choose to pre-fill the file with data the easiest method is to use the dd command. PLEASE BE CAREFUL – dd is often nicknamed disk destroyer because it will happily overwrite any data you tell it to, including the stuff you wanted to keep if you make a mistake typing the command!

To fill the file with all zeros simply run this command:

dd if=/dev/zero of=<your file> bs=1M count=<your file size in MiB>

So for the above file you would run:

dd if=/dev/zero of=MyDrive.img bs=1M count=500

If you want to fill it with random data instead just swap /dev/zero for /dev/urandom or /dev/random in the command:

dd if=/dev/urandom of=MyDrive.img bs=1M count=500

Format and mount the virtual volume

Next up we need to give the volume a filesystem. You can either do this via the command line or using a graphical tool. I’ll show you an example of both.

From the terminal you would run the appropriate mkfs command on the file. As an example this will format the file above using the ext3 filesystem:

mkfs -t ext3 MyDrive.img

You may get a warning that looks like this

MyDrive.img is not a block special device.
Proceed anyway? (y,n)

Simply type the letter ‘y’ and press Enter. With any luck you’ll see a bunch of text telling you exactly what happened and you now have a file that is formatted with ext3!

If you would rather do things the graphical way you could use a tool like Disks (gnome-disk-utility) to format the file.

From the menu in Disks, select Disks -> Attach Disk Image and browse to your newly created file (i.e. MyDrive.img).

Don't forget to uncheck the box!

Don’t forget to uncheck the box!

Be sure to uncheck “Set up read-only loop device”. If you leave this checked you won’t be able to format or write anything to the volume. Select the file and click Attach.

This will attach the file, as if it were a real hard drive, to your computer:

MyDriveAttached

Next we need to format the volume. Press the little button with two gears right below the attached volume and click Format. Make sure you do this for the correct ‘drive’ so that you don’t accidentally format your real hard drive!

Make sure you're formatting the correct drive!

Make sure you’re formatting the correct drive!

From this popup you can select the filesystem type and even name the drive. You may also use the “Erase” option to write zeros to the file if you wanted to do it here instead of via the terminal as shown previously. In the image above the settings will format the drive using the ext4 filesystem. Click Format, confirm the action and you’re done. Disks will format the file and even auto-mount it for you. You can now copy files to your mounted virtual drive. When you’re done simply eject the drive like normal or press the square Stop button in Disks. To use that same volume again in the future just re-attach the disk image using the steps above.

To mount the formatted file from the terminal you will need to first create a folder to mount it to. Let’s say we wanted to mount it to the folder /media/MyDrive. First create the folder there:

sudo mkdir /media/MyDrive

Next mount the file to the folder:

sudo mount -t auto -o loop MyDrive.img /media/MyDrive/

Now you can copy files to the drive just like before. When you’re finished unmount the volume by running this command:

sudo umount /media/MyDrive/

And there you have it. Now you know how to create virtual volume files that you can use for just about anything and easily move from computer to computer.

This post originally appeared on my personal website here.




I am currently running a variety of distributions, primarily Linux Mint 17.
Previously I was running KDE 4.3.3 on top of Fedora 11 (for the first experiment) and KDE 4.6.5 on top of Gentoo (for the second experiment).

Set up KeePass Auto-Type on Linux

June 8th, 2014 3 comments

If you’ve used KeePass on Windows you may be very attached to its auto-type feature, where with a single key-combo press the application with magically type your user name and password into the website or application you’re trying to use. This is super handy and something that is sadly missing by default on Linux. Thankfully its also very easy to make work on Linux.

1. Start by installing the xdotool package

On Debian/Ubuntu/etc simply run:

sudo apt-get install xdotool

2. Next find out where the keepass2 executable is installed on your system

The easiest way to do this is to run:

which keepass2

On my system this returns /usr/bin/keepass2. This file is actually not the program itself but a script that bootstraps the program. So to find out where the real executable run:

cat /usr/bin/keepass2

On my system this returns

#!/bin/sh
exec /usr/bin/cli /usr/lib/keepass2/KeePass.exe "$@"

So the program itself is actually located at /usr/lib/keepass2/KeePass.exe.

3. Create a custom keyboard shortcut

linuxmintkeyboardshortcut

The process for this will differ depending on which distribution you’re running but it’s usually under the Keyboard settings. For the command enter the following:

mono /usr/lib/keepass2/KeePass.exe --auto-type

Now whenever you key in your shortcut keyboard combo it will tell KeePass to auto-type your configured username/password/whatever you setup in KeePass. The only catch is that you must first open KeePass and unlock your database.




I am currently running a variety of distributions, primarily Linux Mint 17.
Previously I was running KDE 4.3.3 on top of Fedora 11 (for the first experiment) and KDE 4.6.5 on top of Gentoo (for the second experiment).
Categories: Linux, Tyler B Tags:

Force Thunderbird/Enigmail to use a specific signing (hash) algorithm

June 8th, 2014 No comments

If you’ve had issues trying to get Thunderbird to send your PGP signed e-mail using anything other than SHA-1 there is a quick and easy fix that will let you pick whichever hash you prefer.

1) Open up Thunderbird’s preferences

2) On the Advanced Tab, under General click Config Editor

3) In the about:config window search for “extensions.enigmail.mimeHashAlgorithm” without quotes. Double click on this and enter a value. The value will determine which hash algorithm is used for signing.

The values are as follows:

0: Automatic selection, let GnuPG choose (note that while this may be the default it may also be the one that doesn’t work depending on your configuration).
1: SHA-1
2: RIPEMD-160
3: SHA-256
4: SHA-384
5: SHA-512
6: SHA-224

This post originally appeared on my personal website here.




I am currently running a variety of distributions, primarily Linux Mint 17.
Previously I was running KDE 4.3.3 on top of Fedora 11 (for the first experiment) and KDE 4.6.5 on top of Gentoo (for the second experiment).

How to mount a Windows share on startup

April 28th, 2014 2 comments

I recently invested in a NAS device to add a little bit of redundancy to my personal files. With this particular NAS the most convenient way to use the files it stores is via the Windows share protocol (also known a SMB or CIFS). Linux has supported these protocols for a while now so that’s great but I wanted it to automatically map the shared directory on the NAS to a directory on my Linux computer on startup. Thankfully there is a very easy way to do just that.

1) First install cifs-utils

sudo apt-get install cifs-utils

2) Next edit the fstab file and add the share(s)

To do this you’ll need to add a new line to the end of the file. You can easily open the file using nano in the terminal by running the command:

sudo nano /etc/fstab

Then use the arrow keys to scroll all the way to the bottom and add the share in the following format:

//<path to server>/<share name>     <path to local directory>     cifs     guest,uid=<user id to mount files as>,iocharset=utf8     0     0

Breaking it down a little bit:

  • <path to server>: This is the network name or IP address of the computer hosting the share (in my case the NAS). For example it could be something like “192.168.1.1” or something like “MyNas”
  • <share name>: This is the name of the share on that computer. For example I set up my NAS to share different directories one of which was called “Files”
  • <path to local directory>: This is where you want the remote files to appear locally. For example if you want them to appear in a folder under /media you could do something like “/media/NAS”. Just make sure that the directory exists (create it if you need to).
  • <user id to mount files as>: This defines the permissions to give the files. On Ubuntu the first user you create is usually give uid 1000 so you could put “1000” here. To find out the uid of any random user use the command “id <user>” without quotes.

So for example my added line in fstab was

//192.168.3.25/Files     /media/NAS     cifs     guest,uid=1000,iocharset=utf8     0     0

Then save the file “Ctrl+O” and then Enter in nano.

3) Mount the remote share

Run this command to test the share:

sudo mount -a

If that works you should see the files appear in your local directory path. When you restart the computer it will also attempt to connect to the share and place the files in that location as well. Keep in mind that anything you do to the files there also changes them on the share!




I am currently running a variety of distributions, primarily Linux Mint 17.
Previously I was running KDE 4.3.3 on top of Fedora 11 (for the first experiment) and KDE 4.6.5 on top of Gentoo (for the second experiment).
Categories: Linux, Tyler B Tags: , , , , ,

Ubuntu 14.04 VNC woes? Try this!

April 28th, 2014 No comments

If, like me, you’ve recently upgraded to Ubuntu 14.04 only to find out that for whatever reason you can no longer VNC to that machine anymore (either from Windows or even an existing Linux install) have no fear because I’ve got the fix for you!

Simply open up a terminal and run the following line:

gsettings set org.gnome.Vino require-encryption false

Obviously if you use VNC encryption you may not want to do this but if you’re like me and just use VNC on the local network it should be safe enough to disable.




I am currently running a variety of distributions, primarily Linux Mint 17.
Previously I was running KDE 4.3.3 on top of Fedora 11 (for the first experiment) and KDE 4.6.5 on top of Gentoo (for the second experiment).

Cloud Saves for Minecraft

February 21st, 2014 No comments

I’ve recently become addicted to Minecraft. I realize that I’m late to this game, having only recently discovered it despite its popularity over the past couple of years. As readers know, I typically switch between a few different machines throughout my day, and indeed between a few different operating systems. Luckily, Minecraft is portable and can be played on any platform – but how to go about transferring saved games?

By default, Minecraft puts your user data and game saves in a hidden folder within your home folder. In particular, save game data is stored at ~/.minecraft/saves/. My solution to the cloud save problem was to create a minecraft folder in my DropBox, and then symlink the default save folder to this location.

Start by creating a folder in your DropBox (or other cloud share platform) folder:

jonf@UBUNTU:~$ mkdir ~/Dropbox/minecraft
jonf@UBUNTU:~$ mkdir ~/Dropbox/minecraft/saves

Next, back up your existing save games folder. We’ll restore these once the symlink has been created.

jonf@UBUNTU:~$ mv ~/.minecraft/saves/ ~/.minecraft/saves.old

Now create the symlink between the new DropBox folder and the save game location:

jonf@UBUNTU:~$ ln -s ~/Dropbox/minecraft/saves/ ~/.minecraft/saves
jonf@UBUNTU:~$ ls -la ~/.minecraft
total 24
drwxrwxr-x  3 jonf jonf  4096 Feb 21 08:58 .
drwx------ 43 jonf jonf 12288 Feb 21 08:55 ..
lrwxrwxrwx  1 jonf jonf    38 Feb 21 08:58 saves -> /home/jonf/Dropbox/minecraft/saves/
drwxrwxr-x  2 jonf jonf  4096 Feb 21 08:55 saves.old

As you can see, the saves folder under the .minecraft folder now points to the saves folder that we created inside of our DropBox folder. This means that if we put anything inside of that folder, it will be automatically written to the DropBox folder, which will be synced to all of my other computers.

Finally, let’s restore the existing saved games folder into the new shared folder:

jonf@UBUNTU:~$ mv ~/.minecraft/saves.old/ ~/.minecraft/saves

If I take the same steps on my other machines, then I can play Minecraft from any of my machines with my saved games always available, no matter where I am. Keep in mind that the ln syntax for Mac OSX is slightly different than the example above. The steps remain the same, but you’ll want to check the docs if you’re trying to adopt these steps for a different platform.




On my Laptop, I am running Linux Mint 12.
On my home media server, I am running Ubuntu 12.04
Check out my profile for more information.

Extend the life of your SSD on linux

February 9th, 2014 2 comments

This past year I purchased a laptop that came with two drives, a small 24GB SSD and a larger 1TB HDD. My configuration has placed the root filesystem (i.e. /) on the SSD and my home directory (i.e. /home) on the HDD so that I benefit from very fast system booting and application loading but still have loads of space for my personal files. The only downside to this configuration is that linux is sometimes not the best at ensuring your SSD lives a long life.

Unlike HDDs, SSDs have a finite number of write operations before they are guaranteed to fail (although you could argue HDDs aren’t all that great either…). Quite a few linux distributions have not yet been updated to detect and configure SSDs in such a way as to extend their life. Luckily for us it isn’t all that difficult to make the changes ourselves.

Change #1 – noatime

The first change that I do is to configure my system so that it no longer updates each files access time on the SSD partition. By default Linux records information about when files were created and last modified as well as when it was last accessed. There is a cost associated with recording the last access time and including this option can not only significantly reduce the number of writes to the drive but also give you a slight performance improvement as well. Note that if you care about access times (for example if you like to perform filesystem audits or something like that) then obviously disabling this may not be an option for you.

Open /etc/fstab as root. For example I used nano so I ran:

sudo nano /etc/fstab

Find the SSD partition(s) (remember mine is just the root, /, partition) and add noatime to the mounting options:

UUID=<some hex string> /               ext4    noatime,errors=remount-ro

Change #2 – discard

UPDATE: Starting with 14.04 you no longer need to add discard to your fstab file. It is now handled automatically for you through a different system mechanism.

TRIM is a technology that allows a filesystem to immediately notify the SSD when a file is deleted so that it can more efficiently manage the underlying storage and improve the lifespan of the drive. Not all filesystems support TRIM but if you are like most people and use ext4 then you can safely enable this feature. Note that some people have actually had drastic write performance decreases when enabling this option but personally I’d rather have that than a dead drive.

To enable TRIM support start by again opening /etc/fstab as root and find the SSD partition(s). This time add discard to the mounting options:

UUID=<some hex string> /               ext4    noatime,errors=remount-ro,discard

Change #3 – tmpfs

If you have enough RAM you can also dedicate some of it to mounting specific partitions via tmpfs. Tmpfs essentially makes a fake hard drive, known as a RAM disk, that exists only in your computer’s RAM memory while it is running. You could use this to store commonly written to temporary filesystems like /tmp or log file locations such as /var/logs.

This has a number of consequences. For one anything that gets written to tmpfs will not be there the second you restart or turn the computer off – it never gets written back to a real hard drive. This means that while you can save your SSD all of those log file writes you also won’t be able to debug a problem using those log files on a computer crash or something of the like. Also being a RAM disk means that it will slowly(?) eat up your RAM growing larger and larger the more you write to it between restarts. There are options for putting limits on how large a tmpfs partition can grow but I’ll leave you to search for those.

To set this up open /etc/fstab as root. This time add new tmpfs lines using the following format:

tmpfs   /tmp    tmpfs   defaults  0       0

You can lock it down even more by adding some additional options like noexec (disallows execution of binaries on the filesystem) and nosuid (block the operation of suid, and sgid bits). Some other locations you may consider adding are /var/log, /var/cache/apt etc. Please read up on each of these before applying them as YMMV.

Categories: Hardware, Tyler B Tags: , , , , ,

Change the default sort order in Nautilus

February 9th, 2014 1 comment

The default sort order in Nautilus has been changed to sorting alphabetically by name and the option to change this seems to be broken. For example I prefer my files to be sorted by type so I ran

dconf-editor

and browsed to org/gnome/nautilus/preferences. From there you should be able to change the value by using the drop down:

 

Seems easy enough

Seems easy enough

Unfortunately the only option available is modification time. Once you change it to that you can’t even go back to name. This also appears to be a problem when trying to set the value using the command line interface like this:

dconf write /org/gnome/nautilus/preferences/default-sort-order type

I received an “error: 0-4:unknown keyword” message when I tried to run that.

Thanks to the folks over on the Ask Ubuntu forum I was finally able to get it to change by issuing this command instead:

gsettings set org.gnome.nautilus.preferences default-sort-order type

where type could be swapped out for whatever you prefer it to be ordered by.

Great Success!

Great Success!

CoreGTK

January 28th, 2014 2 comments

A while back I made it my goal to put together an open source project as my way of contributing back to the community. Well fast forward a couple of months and my hobby project is finally ready to be shown the light of day. I give you… CoreGTK

CoreGTK is an Objective-C binding for the GTK+ library which wraps all objects descending from GtkWidget (plus a few others here and there). Like other “core” Objective-C libraries it is designed to be a very thin wrapper, so that anyone familiar with the C version of GTK+ should be able to pick it up easily.

However the real goal of CoreGTK is not to replace the C implementation for every day use but instead to allow developers to more easily code GTK+ interfaces using Objective-C. This could be especially useful if a developer already has a program, say one they are developing for the Mac, and they want to port it to Linux or Windows. With a little bit of MVC a savvy developer would only need to re-write the GUI portion of their application in CoreGTK.

So what does a CoreGTK application look like? Pretty much like a normal Objective-C program:

/*
 * Objective-C imports
 */
#import <Foundation/Foundation.h>
#import "CGTK.h"
#import "CGTKButton.h"
#import "CGTKSignalConnector.h"
#import "CGTKWindow.h"

/*
 * C imports
 */
#import <gtk/gtk.h>

@interface HelloWorld : NSObject
/* This is a callback function. The data arguments are ignored
 * in this example. More callbacks below. */
+(void)hello;

/* Another callback */
+(void)destroy;
@end

@implementation HelloWorld
int main(int argc, char *argv[])
{
    NSAutoreleasePool *pool = [[NSAutoreleasePool alloc] init];

    /* We could use also CGTKWidget here instead */
    CGTKWindow *window;
    CGTKButton *button;

    /* This is called in all GTK applications. Arguments are parsed
    * from the command line and are returned to the application. */
    [CGTK autoInitWithArgc:argc andArgv:argv];

    /* Create a new window */
    window = [[CGTKWindow alloc] initWithGtkWindowType:GTK_WINDOW_TOPLEVEL];

    /* Here we connect the "destroy" event to a signal handler in 
     * the HelloWorld class */
    [CGTKSignalConnector connectGpointer:[window WIDGET] 
        withSignal:@"destroy" toTarget:[HelloWorld class] 
        withSelector:@selector(destroy) andData:NULL];

    /* Sets the border width of the window */
    [window setBorderWidth: [NSNumber numberWithInt:10]];

    /* Creates a new button with the label "Hello World" */
    button = [[CGTKButton alloc] initWithLabel:@"Hello World"];

    /* When the button receives the "clicked" signal, it will call the
     * function hello() in the HelloWorld class (below) */
    [CGTKSignalConnector connectGpointer:[button WIDGET] 
        withSignal:@"clicked" toTarget:[HelloWorld class] 
        withSelector:@selector(hello) andData:NULL];

    /* This packs the button into the window (a gtk container) */
    [window add:button];

    /* The final step is to display this newly created widget */
    [button show];

    /* and the window */
    [window show];

    /* All GTK applications must have a [CGTK main] call. Control ends here
     * and waits for an event to occur (like a key press or
     * mouse event). */
    [CGTK main];

    [pool release];

    return 0;
}

+(void)hello
{
    NSLog(@"Hello World");
}

+(void)destroy
{
    [CGTK mainQuit];
}
@end
Hello World in action

Hello World in action

And because Objective-C is completely compatible with regular old C code there is nothing stopping you from simply extracting the GTK+ objects and using them like normal.

// Use it as an Objective-C CoreGTK object!
CGTKWindow *cWindow = [[CGTKWindow alloc] 
    initWithGtkWindowType:GTK_WINDOW_TOPLEVEL];

// Or as a C GTK+ window!
GtkWindow *gWindow = [cWindow WINDOW];

// Or even as a C GtkWidget!
GtkWidget *gWidget = [cWindow WIDGET];

// This...
[cWindow show];

// ...is the same as this:
gtk_widget_show([cWindow WIDGET]);

You can even use a UI builder like GLADE, import the XML and wire up the signals to Objective-C instance and class methods.

CGTKBuilder *builder = [[CGTKBuilder alloc] init];
if(![builder addFromFile:@"test.glade"])
{
    NSLog(@"Error loading GUI file");
    return 1;
}

[CGTKBuilder setDebug:YES];

NSDictionary *dic = [[NSDictionary alloc] initWithObjectsAndKeys:
                 [CGTKCallbackData withObject:[CGTK class] 
                     andSEL:@selector(mainQuit)], @"endMainLoop",
                 [CGTKCallbackData withObject:[HelloWorld class] 
                     andSEL:@selector(hello)], @"on_button2_clicked",
                 [CGTKCallbackData withObject:[HelloWorld class] 
                     andSEL:@selector(hello)], @"on_button1_activate",
                 nil];

[builder connectSignalsToObjects:dic];

CGTKWidget *w = [builder getWidgetWithName:@"window1"];
if(w != nil)
{
    [w showAll];
}

[builder release];

So there you have it that’s CoreGTK in a nutshell.

There are a variety of ways to help me out with this project if you are so inclined to do so. The first task is probably just to get familiar with it. Download CoreGTK from the GitHub project page and play around with it. If you find a bug (very likely) please create an issue for it.

Another easy way to get familiar with CoreGTK is to help write/fix documentation – a lot of which is written in the source code itself. Sadly most of the current documentation simply states which underlying GTK+ function is called and so it could be cleaned up quite a bit.

At the moment there really isn’t anything more formal than that in place but of course code contributions would also be welcome!

Update: added some pictures of the same program running on all three operating systems.

Hello World on Windows

Hello World on Windows

Hello World on Mac

Hello World on Mac

Hello World on Linux

Hello World on Linux

This post originally appeared on my personal website here.




I am currently running a variety of distributions, primarily Linux Mint 17.
Previously I was running KDE 4.3.3 on top of Fedora 11 (for the first experiment) and KDE 4.6.5 on top of Gentoo (for the second experiment).

A tale of a gillion installs

January 21st, 2014 1 comment

Install number one: LMDE 201303.  I was hoping for the best of both worlds, but I got driver issues instead.  LMDE has known ATI proprietary driver install issues.  I followed the Mint instructions and got it working, then got a blank screen after too much tinkering.  I was surprised that LMDE had this problem since Debian doesn’t, and LMDE should be a more polished version of LMDE.  This wasn’t a big deal, but I decided to give Debian a chance.

Install number two: debian stable (7.3).  The debian website has a convoluted maze of installation links, but it’s still fairly easy to find an ISO for the stable version you need.  I installed from the live ISO using a USB key.  The installation and ATI driver update went smoothly, and I thought all was well at first.  I soon realized that about 50% of reboots failed; the audio driver was the culprit.  I installed the latest driver from Realtec/ALSA and it sort of worked, but I was still getting some crap from # dmesg and the audio would crackle with some files.

LMDE.  I live booted LMDE to see if the same issue existed there and it did.

Time for Mint 16.  As expected everything worked.  Man I really wish Ubuntu hadn’t chosen the dark side – their OS is really good.  All of these distros use ALSA audio drivers, so why is Ubuntu the only one that works?   Kernel versions:

debian stable (7.3):
cat /proc/asound/version
Advanced Linux Sound Architecture Driver Version 1.0.24.
Mint 16:
cat /proc/asound/version
Advanced Linux Sound Architecture Driver Version k3.11.0-12-generic.

One more thing to check.  What kernel version is the real debian testing “jessie” using:

http://packages.debian.org/testing/kernel/linux-image-3.12-1-amd64

LMDE 201303 = 3.2
debian stable 7.3 = 3.2
Mint 16 = 3.11
debian testing “jessie - Jan 2014” = 3.12!

I determined to try debian testing before settling for Mint.  I tried a netinstall from USB key which killed my PC and grub bootloader.  The debian stable live iso usb key decided to stop working as well.   I finally got a real DVD debian stable install to work, changed the repositories to point to “jessie” and upgraded.  I was very surprised to see this worked!   I’m having some problems with bash, but all of my day to day software is up and running.  Nice.

TL;DR: LMDE was using an old kernel so I needed the real debian testing (jessie) to solve my driver problems.