SysAdmin Adventures » Zordrak

Rosetta Code

Zordrak — Wed, 01 Jun 2011 12:00:44 +0000

Stumbled across the Rosetta Code site this morning. I can’t remember when I last discovered a site so unbelievably useful; especially for people like me who occasionally dip into languages and then don’t use them again for a long time.

http://rosettacode.org/

Rosetta Code is a programming chrestomathy site. The idea is to present solutions to the same task in as many different languages as possible, to demonstrate how languages are similar and different, and to aid a person with a grounding in one approach to a problem in learning another. Rosetta Code currently has 504 tasks, and is aware of 384 languages, though we do not (and cannot) have solutions to every task in every language.

A very good example from the site:

http://rosettacode.org/wiki/Reverse_a_string

Slackware 13.37 Released

Zordrak — Thu, 28 Apr 2011 09:49:26 +0000

Slackware-13.37 (and Slackware64-13.37) has been released today and I must say I’m extremely happy with it. I previously posted that I thought 13.1 was rushed, and it was, but this release is the polar opposite. Slackware-13.37 has been in beta for nearly two months and has been getting bugfixes, small updates and tweaks that whole time. I’m confident that this is quite simply the best version of Slackware ever to get through the stable door.

I want to personally extend my thanks to the whole Slackware team for their constant efforts to make the core of my infrastructure (and yours too) as good as it can be.

Want a copy now? Right now? Ok. Here’s the official torrents

Torrents for Slackware 13.37, 32-bit x86

Slackware 13.37 x86 DVD ISO (everything)

Torrent for Slackware 13.37, 64-bit x86_64

Slackware 13.37 x86_64 DVD ISO (everything)

Slackware 13.37 – Xorg + Hal

Zordrak — Tue, 29 Mar 2011 12:17:11 +0000

The divorce was a long time coming. The papers are finally signed. Xorg has dumped hal and eloped with udev.

Keyboard layout modifications are back to (almost) normal – but instead of using /etc/X11/xorg.conf, we’re now using /etc/X11/xorg.conf.d/90-keyboard-layout.conf.

To change your keyboard layout from US to GB (for example):

# cp /{usr/share,etc}/X11/xorg.conf.d/90-keyboard-layout.conf
# vi /etc/X11/xorg.conf.d/90-keyboard-layout.conf

Modify the file to replace:

Option “XkbLayout” “us”

With:

Option “XkbLayout” “gb”

.. just as you would have done a few years ago with xorg.conf.

Upgrading Slackware64-current with multilib

Zordrak — Sat, 12 Mar 2011 15:19:01 +0000

In order to upgrade your multilib Slackware64-current box to a more recent -current (or perhaps 13.37):

Make sure you have a copy of the version you want to upgrade to available.
Make sure your slackpkg config points to it

mkdir -p /mirror/slackware
cd !$
lftp -c "open http://connie.slackware.com/~alien/; mirror multilib"
slackpkg update
slackpkg install-new
slackpkg upgrade-all
upgradepkg --reinstall --install-new /mirror/slackware/multilib/current/{*.t?z,slackware64-compat32/*/*.t?z}
slackpkg clean-system

Bear in mind that you need to know what modifications you’ve made to your system in the “clean-system” stage. slackpkg will offer to remove any package that’s not part of the version you’re upgrading to. If you need to keep any extra packages that you’ve installed you need to make sure you don’t uninstall them at this stage. For this reason I heavily recommend that you blacklist SlackBuilds.Org packages in the slackpkg blacklist file.

Blog Downtime

Zordrak — Mon, 06 Sep 2010 12:57:38 +0000

Sorry for the downtime over the last couple of days, people. My server decided to barf up its kernel while I was away camping and driving an M3 and a DB9 for my birthday. Typically, the server was only 5 days from its first uptime anniversary.

Normal service has now been resumed.

Sad Day :: Company Bought

Zordrak — Mon, 26 Jul 2010 09:13:51 +0000

My company has been bought. While this means a lot of good and bad all over the place, it means one thing that’s very sad; I am about to commence work on tearing down the network I have so lovingly crafted over the last four years. Within a year I don’t expect there to be more than one or two Slackware boxes still running, if any. Black armbands please.

Slackware 13.1 & libxfs.h

Zordrak — Mon, 12 Jul 2010 13:15:54 +0000

I was trying to build partclone to read an image created with clonezilla, and discovered it won’t build with XFS support on Slackware because Slackware lacks libxfs.h. I think this is somewhat intentional in that the XFS Makefile only installs the header if you explicitly target “install-qa”. It seems libxfs.h is only supposed to be used by XFS devs and 3rd party software should not require it, and I’m happy with that.

Just in case there is a reason you should need libxfs.h on Slackware:

cp -a /mirror/slackware/slackware-13.1/source/a/xfsprogs ~/.
cd ~/xfsprogs
sed -i -e '93i\make install-qa DIST_ROOT=\$PKG' -e 's/$BUILD:-1$/\1qa/' xfsprogs.SlackBuild
./xfsprogs.SlackBuild
upgradepkg /tmp/xfsprogs*1qa.t?z

You now have libxfs.h installed at /usr/include/xfs/libxfs.h

SlackBuilds :: Watch Out For umask

Zordrak — Thu, 08 Jul 2010 09:38:25 +0000

If you are building your own packages from SlackBuild scripts, then you need to make sure your umask is 022 before you start!

Because of the nature of the shared environment in which I work, I changed my default umask to 002 in /etc/profile. I’ve just discovered a big problem as a result. When directories such as $PKG/etc aknd $PKG/usr are created as part of the SlackBuild, they are created with file permission 775 as per the umask. Then when it comes to installing those directories from the package, the installer overwrites the permissions on the directories in your system with the permissions set in the package.

So, if $PKG/etc was created with 775, your /etc directory will be modified from 755 to 775 and this can do harm. This especially the case with directories such as /etc/mail which are checked by daemons for security before they run. If the permissions are too loose, the daemons don’t run.

Before you run a SlackBuild script, check that your umask is 022!!

Slackware trying to mount NFS shares before the network is ready

Zordrak — Mon, 14 Jun 2010 12:31:15 +0000

I have a right pain of a problem in this network in that individual machines are slow to get network access at boot. I haven’t had the opportunity to properly find out why, but my instinct says the blame lies with the Allied Telesyn switches.

The big problem this causes is that any machines with a remote filesystem, such as an NFS share, in their fstab fail to mount the shares at boot; which means I have to manually ssh in and issue a mount command as root.

The solution is to ask rc.inet2 if it would kindly consider waiting just a little longer for the network to come up and not mount remote filesystems if it doesn’t.

The following patch attempts to ping an always-on host, preferably the host that serves the filesystem(s) you are going to mount.

If a response is received, the boot process continues as normal.
If there’s no response to the first ping:
- A further 5 pings are attempted.
- A countdown is displayed.
- After 6 failed attempts boot continues, but with no attempt to mount remote filesystems.

rc.inet2.diff (download rc.inet2.diff.gz):

--- ./rc.inet2.orig 2007-09-17 23:07:32.000000000 +0100
+++ ./rc.inet2 2010-06-14 14:05:24.237107265 +0100
@@ -15,9 +15,16 @@

# At this point, we are ready to talk to The World...

+lan_test_host="";
+avail=6;
+while ! ping -c1 $lan_test_host &>/dev/null && (( avail-- > 1 ));
+do
+ echo "Waiting for network before mounting remote filesystems... $avail";
+ sleep 1;
+done

# Mount remote (NFS) filesystems:
-if cat /etc/fstab | grep -v '^#' | grep -w nfs 1> /dev/null 2> /dev/null ; then
+if cat /etc/fstab | grep -v '^#' | grep -w nfs 1> /dev/null 2> /dev/null && ((avail)); then
# Start rpc.portmap, /sbin/rpc.lockd, and /sbin/rpc.statd if we find NFS
# volumes defined in /etc/fstab since these will need to be running in order
# to mount them. If they are not running, attempting to mount an NFS
@@ -46,7 +53,7 @@

# Mount remote CIFS filesystems. Note that where possible, using CIFS is
# preferred over SMBFS. SMBFS is no longer actively maintained.
-if cat /etc/fstab | grep -v '^#' | grep -w cifs 1> /dev/null 2> /dev/null ; then
+if cat /etc/fstab | grep -v '^#' | grep -w cifs 1> /dev/null 2> /dev/null && ((avail)); then
echo "Mounting remote CIFS file systems: /sbin/mount -a -t cifs"
/sbin/mount -a -t cifs
# Show the mounted volumes:
@@ -54,7 +61,7 @@
fi

# Mount remote SMB filesystems:
-if cat /etc/fstab | grep -v '^#' | grep -w smbfs 1> /dev/null 2> /dev/null ; then
+if cat /etc/fstab | grep -v '^#' | grep -w smbfs 1> /dev/null 2> /dev/null && ((avail)); then
echo "Mounting remote SMBFS file systems: /sbin/mount -a -t smbfs"
/sbin/mount -a -t smbfs
# Show the mounted volumes:

In order to apply the above patch, do the following as root:

# cd /etc/rc.d
# wget http://blog.tpa.me.uk/wp-content/uploads/2010/06/rc.inet2.diff.gz
# zcat rc.inet2.diff.gz | patch -p1

Do not forget to manually edit your newly patched file to replace “” with a valid hostname or IP address.

Slackware 13.1 and VirtualBox USB

Zordrak — Mon, 14 Jun 2010 10:41:27 +0000

By default, USB support does not work when installing VirtualBox PUEL on a Slackware host. Essentially it is a permissions issue. There are a number of ways around it, but the simplest is this ridiculously small change to rc.S.

rc.S (downloadable rc.S.diff.gz):

--- ./rc.S.orig 2010-03-20 00:14:51.000000000 +0000
+++ ./rc.S 2010-06-14 11:31:16.067169967 +0100
@@ -297,7 +297,7 @@
if grep -wq usbfs /proc/filesystems; then
if ! grep -wq usbfs /proc/mounts ; then
if ! grep -wq usbfs /etc/fstab; then
- /sbin/mount -v usbfs /proc/bus/usb -t usbfs
+ /sbin/mount -v usbfs /proc/bus/usb -t usbfs -o devgid=83,devmode=0664
else
/sbin/mount -v /proc/bus/usb
fi

This patch effectively changes the automatic permissions on USB devices so that the group owner is the plugdev group and so the group owner has write permissions. Make sure any users in the vboxusers group are also in the plugdev group… but you knew that.

In order to apply the above patch, do the following as root:

# cd /etc/rc.d
# wget http://blog.tpa.me.uk/wp-content/uploads/2010/06/rc.S.diff.gz
# zcat rc.inet2.diff.gz | patch -p1

Or just make the change by hand, given how small it is.