This is how I upgraded the Squid package from 3.1.19 to 3.2.6 on my Ubuntu 12.04 installations. The 3.2.x branch contains support for multiple cores, so that's a pretty important update to have. 12.04 is an LTS release, so I'm really not sure why 3.2.6 hasn't been backported to it. Anyhow, here's how I did it:

Set up the dquilt shell alias as described in the Debian New Maintainer's Guide:

alias dquilt="quilt --quiltrc=${HOME}/.quiltrc-dpkg"

Create ~/.quiltrc-dpkg containing

The other day, I was trying to use Linux' inotify(7) functionality in a Python script. The obvious contender seems to be pynotify, being the top Google result, as well as being mentioned in the O'Reilly title Python for Unix and Linux System Administration. Unfortunately, I found myself dumbfounded by its API. The native inotify(7) functionality is simple and elegant, what does a scripting wrapper have to add on top of it? If it were an abstraction that unifies the various platform-specific filesystem notification approaches, I would be able to digest a thick, opinionated API, but a mere wrapper for one particular platform should be just that: a wrapper, as thin as possible.

I recently evaluated several open-source HTTP proxy servers. I was looking for something lightweight and fast, without a persistent cache or with no cache at all.

First of all, follow the accepted answer in this StackOverflow question. That takes care of the basics. Second, if your application is using ARC (as it should if it targets Lion and higher) you may have to explicitly disable garbage collection for the System Preferences application. System Preferences is using ARC by default but there seems to be some crutch in place that causes it to switch to GC when launched by Xcode. This crutch will cause

Garbage Collection enabled !

in the debug log and the

To use the “...” preferences pane, System Preferences must quit and reopen.

error sheet to be displayed when your preference pane is selected. Clicking OK will restart System Preferences and you will lose your debug session.

I found that setting OBJC_DISABLE_GC to YES will override the crutch and cause System Preferences to start with ARC enabled, letting you debug your preference pane as intended. In Xcode, edit the scheme (Menu Product - Edit scheme), select the Run action and click the arguments tab. To the Environment Variables list, add an entry for OBJC_DISABLE_GC and YES.

This is on Xcode 4.5.2 (4G2008a) on OS X 10.8.2.

The mechanism we employ to increase the security, integrity and privacy of systems and the communication between them are never absolutely effective. They evolve over time, some are abandoned, others are hardened incrementally, yet others are replaced by supreme alternatives. The encryption algorithms deemed secure today may become obsolete with a new mathematical break-through or with the advent of computational devices that are orders of magnitude more performant compared to their predecessors. Security, as a goal, requires continued effort, and, as a property of a system, can be measured on a scale. It involves making trade-offs: only if the prize is high, do we need to go the extra mile, otherwise we do get away with compromising on security, pun intended.

I recently was exposed to an example of the all-or-nothing approach to security. Google suddenly (as in 'without notice') dropped support for self-signed certificates when fetching mail from external POP3 accounts over secure connections. Granted, self-signed certificates do compromise the security of TLS. But that doesn't justify someone deciding for us that we shouldn't be using them. Interestingly, the suggested mitigations involve abstinence (as in "you can always leave Gmail") and ignorance (as in "you can always use unencrypted POP3").

I recently had to get into the Mosh pit with my good old friend Hardy Heron aka Ubuntu 8.04 TLS.

wget --no-check-certificate https://github.com/keithw/mosh/zipball/mosh-1.2.2
mv mosh-1.2.2 mosh-1.2.2.zip
unzip mosh-1.2.2.zip
cd keithw-mosh-df955aa
sudo sed -i -r 's/#\s*(.*hardy-backports.*)/\1/' /etc/apt/sources.list
sudo apt-get update
sudo apt-get install build-essential autoconf automake libprotobuf-dev \
                     protobuf-compiler libncurses5-dev zlib1g-dev libio-pty-perl
./autogen.sh
protobuf_CFLAGS=" " protobuf_LIBS="-lprotobuf" ./configure --prefix="/usr"
sed -i s/LITE_RUNTIME/SPEED/ src/protobufs/*.proto
make
sudo make install

I had a hard time interpreting Apple's documentation of NSTreeController's mutator methods and their corresponding canXyz methods. My experiments did reveal symmetry in and consistency among the semantics of these methods, it's just that their naming is a bit odd (I say that coming from a strong Java background). The docs didn't help much either. I only investigated NSTreeController in entity mode, but I would guess that these methods behave identically in object mode as far as the pre-conditions and the position of the new node are concerned.

• add: Creates a new entity and makes it the last sibling of the selected entity. IOW, the new entity becomes the last child of the selected entity's parent. Without a selection, the entity becomes the last top-level (orphan) entity. Think appendSibling.
• canAdd: Have never observed it to be false.
• insert: Creates a new entity and makes it a sibling of the selected entity, immediately preceding it. Without a selection, the entity becomes the first top-level entity. Think prependSibling.
• canInsert: Have never observed it to be false.
• addChild: Does nothing if the selected entity is a leaf. Otherwise, creates a new entity and adds it as the last child of the selection. Think appendChild.
• canAddChild: False if selection is a leaf.
• insertChild: Does nothing if the selected entity is a leaf. Otherwise, creates a new entity and adds it as the first child of the selection.Think prependChild.
• canInsertChild: False if selection is a leaf.

Please not that these are empirical findings. I am pretty confident that they are accurate for the mutators, I am pretty sure that they are incomplete for the canXyz methods. In other words, even if canAdd seems to be true all the time, I wouldn't assume that add always succeeds and still bind to canAdd.

The awesome Hudson Continuous Integration project seems to be undergoing some organizational changes at the moment. Its leader, Kohsuke Kawaguchi has left Sun/Oracle and started up his own company revolving around professional services for Hudson, it seems. Let's hope this is not going to be one of those messy "open-source project going commercial" scenarios. Anyways, one of the more immediate problems caused by the changes is that the Debian package repository did not get any updates since late March. In a Hudson mailing list Kohsuke casually announced that he'd be pushing packages to this Hudson CI Debian and Ubuntu package repository but this fact isn't reflected on the official Hudson website yet which is why I am mentioning it here, putting all of my SEO weight behind the link ;-).

Update 06/27/2010: This workaround is still necessary for Lucid (10.04 LTS) and Precise (12.04 LTS). These instructions still work for those releases with minor adjustments (see the updates at the end of the article).

This forum post got me started but I got stuck in various places and thought I'd summarize what worked for me. I'm not going to explain much but if you're going to work with Bind and DLZ you probably know what you're dealing with. I also won't go into configuring DLZ because that depends on your particular DB schema and there is sufficient documentation on the DLZ website.

We need MySQL of course:

There are plenty of openly accessible DNS servers available that do name resolution for you. Most Internet providers run them for their customers. There are also DNS providers that encourage you to replace your ISP's name server with theirs. OpenDNS is one example. They even do it without charging you! But remember, hardly anything on the Internet is free. Someone will have to pay the bill. AFAIK, OpenDNS' business model is based on advertising revenue, so the advertiser pays the bill. This is how it works: If you accidentally type a URL with a nonexistent domain name, OpenDNS will resolve it to one of their web servers instead of returning an NXDOMAIN error. The web server will then serve a page with web search results related to the mistyped domain name and some advertisements.

The dbd-mysql gem assumes (?) an i386 architecture when building the native component of the driver. You'll need to set ARCHFLAGS appropriately and point the build at the installation of MySQL.

sudo env ARCHFLAGS="-arch x86_64" \
     gem install mysql -- \
     --with-mysql-config=/usr/local/mysql/bin/mysql_config

That should fix it.

I use Google Notifier to have my Gmail account checked for new mail periodically and automatically. I have a secondary Gmail account that I don't use that often but that I would like to have notifier check as well. Unfortunately, Google Notifier currently supports a single Gmail account only. Here's a simple hack that works well for a few gmail accounts. In a nutshell, you need to clone the application package and modify the bundle id in the clone's Contents/Info.plist file.

1. Copy the Google Notifier application from Applications to a temporary location.

I'll have to break sad news to you: /etc/resolv.conf has been made redundant in Mac OS X. The dig and nslookup utilities still read it but most applications use a different mechanism for picking DNS servers when resolving host names. They generally go through Darwin's resolver library which instead of reading /etc/resolv.conf looks up DNS servers via the SystemConfiguration framework backed by configd. Survival of the fittest, I guess, or, Darwin's intelligent design.

Ok, ok, I'll stop trying to be funny ... Anyways, this would be all swell if there wasn't the occasional need for manually specifying DNS servers. For me this need typically arises when I connect to a VPN managed by an operator from hell. After hours and hours of hard work (my fingertips still hurt from all the googling) I present to you a solution:

With the VPN connected, launch scutil with root privileges:

hannes-mbp:~ Sysop$ sudo scutil
Password:

List all network services with DNS configuration:

> list State:/Network/Service/[^/]+/DNS
  subKey [0] = State:/Network/Service/A3551F2D-62CE-1234-B79A-6EE50CA7AE30/DNS
  subKey [1] = State:/Network/Service/F194302A-846C-4321-9325-6813DAE148F2/DNS

Pick one and show its contents.

> show State:/Network/Service/A3551F2D-62CE-1234-B79A-6EE50CA7AE30/DNS
<dictionary> {
  SupplementalMatchDomains : <array> {
    0 : 
  }
  ServerAddresses : <array> {
    0 : 192.168.1.74
    1 : 217.0.43.81
  }
  SupplementalMatchOrders : <array> {
    0 : 100000
  }
}

Ahh, this is the one! So let's get rid of those pesky servers. Obtain a working copy of the DNS configuration entry. It's called ... drum roll ... well, obviously: "d" (rolls eyes).

> d.init
> get State:/Network/Service/A3551F2D-62CE-1234-B79A-6EE50CA7AE30/DNS
> d.show
<dictionary> {
  SupplementalMatchDomains : <array> {
    0 : 
  }
  ServerAddresses : <array> {
    0 : 192.168.1.74
    1 : 217.0.43.81
  }
  SupplementalMatchOrders : <array> {
    0 : 100000
  }
}

Reset the ServerAddresses entry to an empty array:

> d.add ServerAddresses *
> d.show
<dictionary> {
  ServerAddresses : <array> {
  }
  SupplementalMatchDomains : <array> {
    0 : 
  }
  SupplementalMatchOrders : <array> {
    0 : 100000
  }
}

Write the working copy back:

> set State:/Network/Service/A3551F2D-62CE-1234-B79A-6EE50CA7AE30/DNS

Note, that the line

d.add ServerAddresses *

clears the ServerAddresses array, thereby removing all DNS-servers tied to that particular connection ("service" in Apple-talk). Without service-specific DNS servers, Mac OS will fall back to DNS servers from other network services. Not sure how exactly that works. If you want to specify particular DNS servers, use

d.add ServerAddresses * 10.0.1.2 112.21.44.66

By the way, the "*" signifies array values, so it's not some kind of wild card.

I have been converted. After having preferred Windows on the desktop for the past 15 years, after six generations of

Yet Another Way To Screw Up The Control Panel,^™

I felt the urge to try something else. Something that

Just Works.^™

Those fifteen years were an interesting ride but for some reason the pride and satisfaction of finding just the right combination of registry settings that would let me mount a Samba share had worn off. I want to spend my time on something creative. Defragmenting the registry, scanning regularly for malware, and trying to find anti-virus software that doesn't take five minutes to load is fun and all, but how about an operating system that doesn't need any of that? You guessed right, I have become a Mac user. Enough of the trivialities, in this article I would like to list a handful of very useful Mac OS X applications and utilities I couldn't live without anymore.

Wireshark has a preference setting for the font of the capture display but it won't let you change the main font used for other UI elements such as like menu, toolbar and dialog windows. The default for the main font is illegibly small on my Mac OS X Leopard system -- I used Macports to install Wireshark and its dependencies. To fix it you need to add the gtk-font-name setting to your .gtkrc-2.0 preference file:

echo 'gtk-font-name = "Sans 14"' >> ~/.gtkrc-2.0

This will affect all applications using the GTK 2.0 toolkit but I guess that's ok.

A close relative of mine asked me to help him with choosing, installing and maintaining a blog for him. I am a big fan of Drupal (the software behind this blog, in case you were wondering) but just couldn't bring myself to recommend it. Don't get me wrong, Drupal is IMHO superior in almost all technical aspects but its user interface is just not as easy to use as WordPress. The person in question being a fairly inexperienced user of web technologies, usability was a major concern. The result can be admired at Hartwig Schmidt's blog.

I use mod_authn_dbd to check HTTP authentication credentials against a MySQL database. After switching from Basic to Digest authentication I got 500 errors and No DBD Authn configured! in the server's error log. It took me a while to realize that it wasn't enough to change

… is actually easy thanks to Dnsruby. The following code illustrates that:

Jsp2X is a command line utility for batch conversion of JSP pages to JSP documents, i.e. JSPs in well-formed XML syntax (aka JSPX, see chapter 5 of the JavaServer Pages^TM 1.2 Specification and chapter 6 of the JavaServer Pages^TM 2.0 Specification). It is written in Java and incorporates a parser derived from a combined JSP+XHTML grammar using the ANTLR parser generator. It tries very hard to create JSPX output that portable across engines. Jsp2X was designed to be used in an iterative fashion in which it alerts the user of potential problems in the input.

Whether a VPN connection has the "Use default gateway on remote network" option enabled has big impact on how network traffic from your machine is routed.

Today I ran into a subtle issue regarding the order in which Windows Vista queries connection-specific DNS servers. I tested a setup with a PPTP VPN server that also provides DNS name resolution services to its VPN clients. For that purpose I ran both a BIND 9 name server and a Poptop PPPD daemon on the same box. It is dual-homed, i.e. one interface is the private interface of the VPN tunnel endpoint and the other one is the public Ethernet interface through which the server is linked to the internet. I configured BIND to listen on both interfaces.

It took me sometime to find Ubuntu torrents that work. I noticed that the .torrent files on the official Ubuntu server and its mirrors point to dead torrents. After some digging, I found this tracker to be most up to date. In case you're stumbling over this problem too, give it a try. It seems to be the official Ubuntu tracker.

[This article is now somewhat obsolete because vmware-server have been included the official portage tree. There is no need for a separate overlay. The bug reports still apply. This is an updated version of a two previous article on the subject.]

The new VMware Server is going to replace VMware's GSX Server product. And it's more than just a new name: VMware will supposedly release it free of charge. Being still in beta testing, there are currently no stable ebuilds available for it on Gentoo Linux. Fortunately, Mike Auty and others are working on one and they are doing a fine job. They also seem to be streamlining and consolidating other related VMware ebuilds. You can keep track of their progress on these Bugzilla bugs:

• Problems regarding the vmware-module ebuild: 137422.
• Problems regarding the vmware-player ebuild: 137423.
• Problems regarding the vmware-server ebuild: 137424.
• Problems regarding the vmware-server-console ebuild: 137425.
• Problems regarding the vmware-workstation ebuild: 137426.
• Problems regarding the vmware-workstation-tools ebuild: 137428.
• Problems regarding the vmware overlay in general: 122500.

The VMware Server ebuilds are not part of the official stable Gentoo portage tree so if you want to install them on your system you will have to jump through a few extra hoops. Fortunately this process has become very convenient and straight-forward thanks to Gunnar Wrobel's layman.

I had difficulties downloading the Ruby Plugin for jEdit today. The main site of the plugin seams to be down and the instructions don't mention certain dependencies. Until Rob fixes those problems, all necessary files will be available for download at Diary Products.

[This is an updated version of a previous article on the subject.]

VMWare is going to replace its GSX Server product with the new VMware Server. And it's going to be more than just a new name: the best thing about it is that VMware releases it free of charge. Being still in beta testing, there are currently no stable ebuilds available for it on Gentoo Linux. Fortunately, Mike Auty is working on one and he is doing a fine job. You should keep track of his progress on Gentoo Bugzilla bug #122500. For people with little Portage experience (author included) it can be a bit complicated to throw together an ebuild from bugzilla attachments.

The frequent visitor of Diary Products knows that it runs on the LightTPD aka Lighty web server. The machine that hosts Diary Products is serving other sites as well so it needs to have some kind of virtual hosting mechanism in place. I use LightTPD's very straight-forward and easy to use mod_simple_vhost module. The only draw-back with LightTPD is that it doesn't support directory specific configuration files similar to Apache's .htaccess files. But this is not such a big deal for me because as much as I liked the convenience of .htaccess, I always considered it a waste of cycles and a security issue. The ideal solution in my opinion would be one which

[02/28/2005: Update - More Changes]
[03/02/2005: Update - Still Bugs in IE]

After this site has been using the old, boring, standard Drupal theme for two years, I am now proud to present my own creation: the new Diary Products theme. It uses the phptemplate engine and is a hybrid between table-based and CSS-based layouts as I am not a follower of the pure "Look Ma, No Tables" approach. There are still a few glitches here and there but overall I am quite happy with it.

Ever wondered why port scanners like nmap are able to tell that some of the ports on your server are protected by a firewall? Have a peek at this nmap transcript:

Starting nmap 3.75 ( http://www.insecure.org/nmap/ ) at 2006-02-23 22:54 CET
Interesting ports on doodah.com (12.34.56.78):
(The 1658 ports scanned but not shown below are in state: closed)
PORT     STATE    SERVICE
21/tcp   open     ftp
22/tcp   open     ssh
53/tcp   open     domain
80/tcp   open     http
3306/tcp filtered mysql

I'm quite sure my firewall blocks access to the mysql port. Yet it bugs me that it is possible to tell that I have MySQL installed on my system simply by performing a port scan.

[This is and outdated version of the article. Read the new version!]

VMware Server is going to replace GSX server. The best thing about it is that VMware releases it free of charge. Being still in beta testing, there are currently no stable ebuilds available for it on Gentoo Linux. Fortunately, Mike Auty is working on one and he is doing a fine job. You should keep track of his progress on Gentoo Bugzilla bug #122500. For people with little Portage experience (author included) it can be a bit complicated to throw together an ebuild from bugzilla attachments.