I recently had a issue getting MySQL to read a specific database. Each time I tried to manually query a table in the database, I received the following error message:

ERROR 1018 (HY000): Can't read dir of './default/' (errno: 13)

I’ve seen this message before as it means that there is a permissions issue. I checked the ownerships and permissions, and everything seemed to be in order.

The only thing special about this database is that I have it symlinked to another partition. This has always worked in the past, so I was stumped.

The problem turned out to be that Ubuntu has AppArmor. This software sets up rules that prevent software from gaining access to different areas of the file system. In my case, AppArmor was preventing read and write access to the actual location of my database files.

The solution was quite easy: First, I added the path that I wanted MySQL to have access to in the AppArmor configuration file for MySQL. Second, I restarted the apparmor service. Here’s the technical details:

1. On my system, the configuration file that controls MySQL permissions through AppArmor are located at /etc/apparmor.d/usr.sbin.mysqld. The following shows the contents of the file as it now exists:

   # vim:syntax=apparmor
   # Last Modified: Tue Jun 19 17:37:30 2007
   #include 
   
   /usr/sbin/mysqld {
     #include
     #include
     #include
     #include
     #include 
   
     capability dac_override,
     capability sys_resource,
     capability setgid,
     capability setuid,
   
     network tcp,
   
     /etc/hosts.allow r,
     /etc/hosts.deny r,
   
     /etc/mysql/*.pem r,
     /etc/mysql/conf.d/ r,
     /etc/mysql/conf.d/* r,
     /etc/mysql/my.cnf r,
     /usr/sbin/mysqld mr,
     /usr/share/mysql/** r,
     /var/log/mysql.log rw,
     /var/log/mysql.err rw,
     /var/lib/mysql/ r,
     /var/lib/mysql/** rwk,
     /var/log/mysql/ r,
     /var/log/mysql/* rw,
     /var/run/mysqld/mysqld.pid w,
     /var/run/mysqld/mysqld.sock w,
     /home/sites/default/mysql/ rw,
     /home/sites/default/mysql/* rw,
   
     /sys/devices/system/cpu/ r,
   }

   The two lines in bold show what I added to the configuation. The first line gives read and write access to the directory itself while the second gives read and write access to the files contained in the directory.

2. After saving the configuration changes, I simply needed to restart the AppArmor daemon. I did this with the following command:

   [chris@rommie ~]$ sudo service apparmor restart
    * Reloading AppArmor profiles
   Skipping profile in /etc/apparmor.d/disable: usr.bin.firefox

My dual monitor setup didn’t work properly in Ubuntu 9.04, Jaunty Jackalope. Fortunately, it does work properly in 9.10, Karmic Kaola. However, this newfound dual monitor setup has given me a new problem: how do I move my panels to the secondary monitor?

My office machine is a laptop. When I get in the office, I hook it up to a 24″ LCD. I’d like to use this external monitor as the primary, which means that I definitely want to have my panels display on it. However, as much as I tried to drag the panels around or play around with settings, there just didn’t seem to be a way to get them over there. However, I just figured it out.

By default, panels are set to expand. This means that the panels will span the entire width or height of the section of the window they occupy. If the expand option is disabled, they turn into self-sizing bar that can be dragged to different edges or centered.

Having the expand option disabled also allows you to grab and edge of the panel and drag it to another screen. Once on the screen you want it on, simply re-enable the expand option and you now have the panel on another screen.

Here’s a step-by-step way of moving a panel to another screen:

1. Right-click the panel you wish to move and select “Properties”.
2. Uncheck the “Expand” option under the “General” tab.
3. Grab one of the edges of the panel by clicking on the left or right end (top or bottom end for vertical panels).
4. Drag the bar to the desired screen and position.
5. Check the “Expand” option in the “Panel Properties” window and click “Close”.

PEAR is PHP’s equivalent of Perl’s CPAN. It offers hundreds of ready-to-use code modules that can make projects go much more quickly than having to hand code everything. However, it never seems like PEAR is easy to get running.

Installing the Needed Software

In Ubuntu, installing the following packages will quickly get you started with PEAR: php5-cli, php5-dev, and php-pear.

Make sure that you read the next section about problems with using PEAR to install PEAR packages if you are running 9.10, Karmic Kaola.

Here’s an example of how to quickly install those packages from the terminal.

[chris@rommie ~]$ sudo apt-get install php5-cli php5-dev php-pear
Reading package lists... Done
Building dependency tree
Reading state information... Done
The following extra packages will be installed:
autoconf autoconf2.13 automake automake1.4 autotools-dev libltdl-dev libssl-dev libtool m4 php5-common shtool zlib1g-dev
Suggested packages:
autobook autoconf-archive gnu-standards autoconf-doc gettext libtool-doc automaken gfortran fortran95-compiler gcj php5-suhosin
The following NEW packages will be installed:
autoconf autoconf2.13 automake automake1.4 autotools-dev libltdl-dev libssl-dev libtool m4 php-pear php5-cli php5-common php5-dev shtool zlib1g-dev
0 upgraded, 15 newly installed, 0 to remove and 5 not upgraded.
Need to get 0B/8,690kB of archives.
After this operation, 27.7MB of additional disk space will be used.
Do you want to continue [Y/n]? y
Selecting previously deselected package m4.
(Reading database ... 127272 files and directories currently installed.)
Unpacking m4 (from .../archives/m4_1.4.13-2_i386.deb) ...
...

With these packages, you are ready to roll with PHP and PEAR in Ubuntu.

Problem with Ubuntu 9.10 Karmic Kaola

A great thing about PEAR is that you can quickly install packages with a simple command. For example, “sudo pear install PHP_Parser-0.2.1″ will install the PHP_Parser package. However, this doesn’t work properly in Ubuntu 9.10, Karmic Kaola.

Output of the standard PEAR install command can be seen below:

[chris@rommie ~]$ sudo pear install PHP_Parser-0.2.1
downloading PHP_Parser-0.2.1.tgz ...
Starting to download PHP_Parser-0.2.1.tgz (70,782 bytes)
.................done: 70,782 bytes

While this doesn’t look wrong, it has actually failed. Rather than installing the package, it has simply downloaded the archive, encountered an unchecked error, and crashed. A successful installation has a message saying that the installation is successful.

This problem can be easily fixed by giving the install command the “-Z” option. For example:

[chris@rommie ~]$ sudo pear install -Z PHP_Parser-0.2.1
downloading PHP_Parser-0.2.1.tar ...
Starting to download PHP_Parser-0.2.1.tar (Unknown size)
.............................................................................done: 533,504 bytes
install ok: channel://pear.php.net/PHP_Parser-0.2.1

Notice the “install ok: …” portion of the message. That’s what you should see at the end of a successful installation.

For more details on this bug, please check out Bug #451314 on the Ubuntu bug tracker.

I just encountered an odd issue with Ubuntu 9.10, Karmic Kaola. I had music playing in the background, I adjusted the volume, and I noticed that there wasn’t any change in the volume level. Even maxing out the volume and muting it had no effect.

After wondering if the problem was that I went insane, I looked in Sound Preferences (right-click the volume icon and select Sound Preferences) and found that “RV635 Audio device [Radeon HD 3600 Series] Digital Stereo (HDMI)” was selected under the device output. This means that Ubuntu was trying to send audio over my HDMI connection rather than through my headphone jacks.

This wasn’t a problem last night, so it might be due to the fact that my external monitor at the office runs over the HDMI connection, so it automatically switched to the HDMI audio output. In one way, this is nice, in another way, it will frustrate me to no end if it does this every time I’m at the office. If I’m right that it automatically switched upon detecting an active HDMI connection, then wouldn’t it be better to make it easier to provide a notification on where to switch the audio output rather than just switching it and causing confusion?

Switching the option to “Internal Audio Analog Stereo” instantly fixed the problem.

Oddly enough, when I manually selected the HDMI output again, it muted the analog output. So, it seems that it may not be a complete switchover or possibly just a bug. I’ll continue to see how the situation plays out and make a Ubuntu bug report if necessary.

Ubuntu 9.10, Karmic Kaola, launched earlier this week. One of the key new features in this release is Ubuntu One. Unfortunately, from what I’ve seen, this new feature/product launch has been anything but smooth.

Ubuntu One is one of the new ways that Canonical, the creators of Ubuntu, is trying to generate some revenue based on their distro. Ubuntu One is a hosted file storage solution that allows users to keep a folder and all of its content synced between multiple computers. All users get 2GB of storage for free with the option of increasing the store to 50GB for $10/month.

Since this new offering has many Ubuntu users very excited, I thought I’d give it a try as soon as I installed the new release. However, I was instantly met with a very big message telling me that something was wrong.

Launch Day: Problem 1

When I first started Ubuntu One, the following notification appeared:

Capabilities Mismatch
There was a capabilities mismatch while attempting to connect to the Ubuntu One server. You may have installed a newer version of the client, for which the server does not yet provide support. A new version of the server should be accessible soon. Please be patient while we update.

Ubuntu is supposed to be a Linux distro designed for the average computer user. Since this large message appears for a short period of time and it isn’t easily understood, I think that this message could very easily give users a very bad first experience. I believe it would be much more simple to simply say the following:

Server Connection Failed
Please ensure that you have installed all software updates and try again at a later time.

The reason why I believe the software update portion should be included is because the problem wasn’t the server, it was the client. This morning my system told me some updates were available, and a few of these updates got rid of the “Capabilities Mismatch” problem and allowed the software to connect properly.

The packages that fixed this are the following:

• python-ubuntuone-client
• ubuntuone-client
• ubuntuone-client-gnome

Each of these were updated to version 1.0.2-0ubuntu2. After the update, I closed the Ubuntu One software, restarted it, and the folder sync worked as expected. However, this is when another problem became clear.

Houston, We Have a Problem… Again

There are two parts to the Ubuntu One system. The first is the server/client connection that actively syncs the Ubuntu One folder between the computer and the Ubuntu One server. The second is an online system you can access through the browser. This online system allows you to manage folders and files from inside your browser.

When I first started to play with Ubuntu One, even though the folder sync didn’t function, the web access system did. Using this method allowed me to get a feel for what Canonical was aiming to offer its users. As soon as the server/client issue was fixed, I decided to play around with syncing files and then looking at them on the online system. This is when I found Ubuntu One’s second problem.

Disappointingly, as soon as Ubuntu One’s client started to work properly, their online system failed. So, is this out of the kettle and into the fire?

Again, this failed in a manner that is difficult to understand. You set up a Ubuntu One account by using a Launchpad account. I went to one.ubuntu.com, the Ubuntu One site, clicked “Sign In”, input my login details, and was redirected to the home page again with no feedback message. So, I clicked “Sign In” again, and I was once again redirected back to the homepage. Seems like some authentication issues were going on between the Ubuntu One and Launchpad systems.

As with the previous issue, my problem isn’t how the system failed — I’m a programmer, I know how things can go wrong — it’s with the fact that no feedback was given to the user. It simply didn’t work.

Conclusion

As I finish up this post, I see that Ubuntu One’s online system is functional again. However, as I’ve tested this throughout the day, it seems like it was down for at least a few hours. Overall, this is not a bad downtime, but it does tarnish the launch.

To be frank, I feel a bit bad being so harsh to software and services that I am getting access to for free; however, as per Canonical’s own press release, they are extremely-focused on the user experience. As a user, I have to say that my experience with the new Ubuntu One service was less than good.

I know that Mark Shuttleworth, founder of Canonical, believes that Ubuntu can take on Microsoft’s Windows head on. I also believe that Ubuntu has this potential; however, launch experiences like this aren’t going to win any new fans. One of the biggest disappointments that many people have with Microsoft is that many of their products, Windows included, feel like they were rushed out of development just to get a release.

Considering that Ubuntu One and Ubuntu are both Canonical creations, it looks really bad when Canonical can’t even get their own products to work together properly.

I recently tutored a friend in C coding. Since I hadn’t worked with C in at least 8 years, I really needed to have some references to rely on for syntax and other specifics. Fortunately, there are some easy man pages that can be installed in Ubuntu that offer helpful information that I was able to use to help refresh my memory.

These man pages are easily installed by installing the manpages-dev package. You can install this package via Synaptic or directly on the command line. I like the command line method personally, so I ran sudo apt-get install manpages-dev from the command line to quickly install the package.

After installing the package, I’m able to access man pages for functions such as printf, opendir, and putc. For each function, it shows the valid syntax as well as what library is required to make use of the function.

The information isn’t limited to functions as you can also access information on the libraries, such as stdio or string.

To access any of this information, simply run man [function or library name] such as man stdio.

This package isn’t limited to C functions/libraries. It is a general use Linux development suite of man pages. For a full list of what is installed, check out the file list.

In Linux, clicking the middle mouse button (or mouse wheel) pastes the most recently highlighted text from any application. This is useful; however, it has an extremely-annoying side-effect in Firefox. Whenever I middle-click outside of entry fields, I get an annoying pop-up that says: “The URL is not valid and cannot be loaded.” This frustrates me to no end. It usually happens when I accidentally nudge my mouse and miss middle-clicking a link in order to open it in a new tab.

So, why is it doing this? Turns out that, by default, Firefox for Linux allows you to use this middle-click to paste functionality to allow you to navigate to a highlighted URL simply by middle-clicking non-editable portions of the page. When an invalid URL is the result of the paste, the annoying popup appears.

Today, I found out how to get rid of this annoyance.

Open a new tab in Firefox and navigate to “about:config”. This will take you to an interface that allows you to tweak and configure very specific functionality of Firefox.

In the “Filter:” text box, enter “middlemouse.contentLoadURL”. This should present a single entry that lists the option as having a value of “true”. Simply double-click the listing to change the value to “false”. The effect is instantaneous.

Now when you middle-click outside of editable areas in Firefox, it will no longer try to navigate to a URL. This change only modifies the navigation to URL functionality; the middle-click to paste in editable areas still functions.

If you like the middle-click to scroll functionality found in other browsers/operating systems, then search for “general.autoScroll” and double-click the listing to change it to true. Now you can middle-click to initiate scrolling.

Firefox 3.5 was released yesterday. This is an exciting new release complete with features such as support for HTML 5, video and audio that works in the browser without the need for plugins, a much faster Javascript engine, a native JSON parser, private browsing mode, support for SVG transformations, and other great enhancements.

I’m sure that you’re just as excited to get started with Firefox 3.5 as I was yesterday when I heard the news. But wait! We’re on Ubuntu, we can’t just install whatever we want, we need to wait for a package. Right? Wrong.

Here’s a really quick way to get 3.5.5 running on your Ubuntu 9.04 system.

Open up Terminal (Applications > Accessories > Terminal) and run the following commands:

1. cd /tmp
2. wget "http://download.mozilla.org/?product=firefox-3.5.5&os=linux&lang=en-US"
   Note: Your download link may be different depending on your country and language. I got the link by clicking the download link, canceling  the automatic download, right-clicking the “Your download should automatically begin in a few seconds, but if not, click here” link, and selecting Copy Link Location.
3. tar xvjf firefox-*.bz2
4. sudo cp -r firefox /usr/lib/firefox-3.5.5
5. sudo mv /usr/bin/firefox /usr/bin/firefox.old
6. sudo ln -s /usr/lib/firefox-3.5.5/firefox /usr/bin/firefox-3.5.5
7. sudo ln -s /usr/bin/firefox-3.5.5 /usr/bin/firefox

Close Firefox and then reopen. You should now be running Firefox 3.5.5.

If for whatever reason you’d like to switch back to your previous version of Firefox, simply run the following commands from Terminal:

1. sudo mv /usr/bin/firefox /usr/bin/firefox.bak
2. sudo mv /usr/bin/firefox.old /usr/bin/firefox

Notice how I even create a backup of the original firefox before replacing it. It is always a good idea to do this if you replace programs yourself. This way you won’t be likely to remove a binary or script that you won’t be able to get back easily.

Now that you are on Firefox 3.5.5, check out some awesome sites that show off some of the new capabilities.

• 3-D cubes built with standard HTML content, including the new native video component.
• Audio player built entirely with HTML, CSS, and Javascript. It doesn’t even use what we commonly think of as images, simply the new Canvas element.
• Video Washing Machine – Add a video to your site, crop it to fit in a circle, put a border around it, have rollover effects that change the filter on the video, and spin the whole thing as it plays. All of this with just the <video> element, CSS 3, SVG, and a bit of JavaScript.
• Add upload progress bars without the use of Flash or insane amounts of scripting.
• Create the illusion of a 3D voxel engine with an image and some creative SVG, scripting, and CSS.
• Apply textures to an animated model.
• Create a text shadow spotlight effect using Javascript and CSS.
• Web developers can now take advantage of custom typography using the new CSS rules.
• Sync page elements with the position in the video. Note that the graphs are canvas elements that are being drawn on.
• Use HTML elements to jump to different positions in audio.

Now that I know how to do this, it seems so easy and straight-forward. To change the default application files of a specific type are opened with, do the following:

1. Right-click a file that you wish to change the default application for and select Properties.
2. Click the “Open With” tab.
3. Select the desired application’s radio button.
   • Additional applications can be added if the one you want is not listed. Use the Add button to find the desired application.
   • You can also remove applications from the list by highlighting the application and clicking the Remove button.
   • Adding applications to or removing applications from this list changes which applications are available in the “Open With” option when you right-click a file.
4. Click the Close button.

Again, it seems so easy and straight-forward now. Go figure.

It’s been a month since my last post. For all my regular readers, I’m very sorry for the absense.

There’s a lot of intersting stuff going on right now. Fortunately, with so much going on, I shouldn’t have a lack of topics to talk about.

To get the old post ball rolling again, how could I not start back up with Ubuntu 9.04?

Ubuntu 9.04, Jaunty Jackalope, is scheduled to be released on April 23rd. Even though it has been a mere six months since Intrepid Ibex went to release, the Jackalope promises some good stuff:

• GNOME 2.26 -  This latest release of GNOME includes a number of features, such as: better multi-monitor support (I look forward to testing this out), a new tool to handle burning disks (Brasero), a plugin promising easier file sharing (even on Bluetooth connections), UPnP media playback support in the GNOME Media Player, new volume control that supports per-application volume control when using PulseAudio (I love this feature in Vista and am excited to get it in Ubuntu). This is just a few of the features that picqued my interest. For more details, see GNOME 2.26′s release notes.
• X.Org Server 1.6 – This new version of the X server promises great improvements to the free drivers available for a large variety of cards, primarily for Intel and AMD graphics. The AMD deal is very exciting. It’s a big topic though, so I’m going to talk about it in more detail later.
• Linux Kernel 2.6.28 – As with most kernel releases, a lot of things have changed. Some of the changes that I found interesting (and that I could understand the value of) are: stable implementation of the Ext4 file system and improved memory management for GPU memory via GEM (the foundation for improving Linux graphics in the future). For a full list of features, check out the breakdown at Kernel Newbies.
• Eucalyptus – Adds cloud computing capabilities to Ubuntu’s server offering. I’m excited to try this out.
• Check out the release notes overview for more information about the new features.

As with most new software, there are some caveats to be alert of. I recommend reading the release notes if you are upgrading. Pay specific attention to the removal of Ctrl+Alt+Backspace support by default and the change to update notifications.

I hope that you are looking forward to the release as much as I am. When the Jackalope goes golden and I have a chance to test it out, I’ll definitely post about my experiences here.