pitter patter on the keyboard

I’m currently working on a rapidly redeployable Gentoo-based virtual machine for service monitoring, statistics graphing and trending and centralized log file collection and analysis. So far it’s just a pretty menu and a collection of third party apps but before I release it I intend on drawing them together through single-sign on. Access is provided over VPN and SSL only.

Xen users frequently deal with raw file system image files. While this isn’t the ideal method for managing virtual machine storage it is the format of choice for redistribution. This article is a simple cheat sheet that will help you deal with sparse and regular image files.

To create a blank image file run:

dd if=/dev/zero bs=1M count=X > image.img

Where X is the size of the file in MB.

To enlarge an image file run:

dd if=/dev/zero bs=1M count=X >> image.img

Where X is the amount of space you want to add in MB.

To create a sparse file run:

dd if=/dev/zero of=image.img seek=X bs=1M count=0

Where X is the size of the image in MB

To enlarge a sparse file run:

dd if=/dev/zero of=image.img seek=X bs=1M count=0

Where seek=8 should be the current size of the sparse file plus the amount of space you wish to grow the image by in MB.

To enlarge an ext2 or ext3 file system to fill an expanded disk image run:

e2fsck -f image.img
e2resizefs image.img
e2fsck -f image.img

To create an ext2 file system on an image file run:

mke2fs image.img

To create an ext3 file system on an image file run:

mke2fs -j image.img

I often find that mke2fs’ defaults for file systems between 2 and 6 gigs are not efficient for full linux installs, make sure you have enough inodes and to really save on space reduce the block size to 1KB. Optionally you can force the defaults for a “small” file system by using the -T flag:

mke2fs -j -T small image.img

This helps clip off a lot of the wasted space created by the (Gentoo in particular but any given flavour’s) large number of small files.

To make a reiserfs file system run:

mkreiserfs image.img

Note that reiser’s ability to incorporate files smaller than the block size into its B-* tree probably makes assigning a smaller (than 4096B) block size more costly than it’s worth.

To expand a reiserfs file system to fill the available space in an image file run

resize_reiserfs image.img

To make an XFS file system run:

mkfs.xfs image.img

XFS caches heavily making it on one hand a decent file-based image performer at the cost of being slightly more fragile than other solutions. Another bonus is it is designed to scale up easily, however I tend to only use XFS as the “mother” FS on battery-backed hardware RAID setups and use ext3 for VM images due to its comparative resilience and the higher level of crash vulnerability virtual machines have over their host counterparts.

To expand an XFS file system to use all available space on a partition image run:

mount -o loop image.img /mnt/image
xfs_growfs /mnt/image

To mount an image file run

mount -o loop image.img /mnt/image

Remember not to perform any operations (like DD) on an image file while it is mounted.

To chroot into an image file with a working linux installation after mounting run:

mount -o bind /dev /mnt/image/dev
mount -t proc none /mnt/image/proc
chroot /mnt/image /bin/bash

Include /bin/bash where the default shell might be less permissive, i.e. standard sh or leave it off if the type of shell is unimportant.

To copy a file system’s contents verbatim to another file system mount both then run:

cp -ax /mnt/image1/* /mnt/image2/

You should do this to a freshly created sparse or regular file to increase the effectiveness of compression when redistributing an image. In a regular file, the empty space that would otherwise be completely zeroed out instead contains remnants of deleted files.

I just bought my first cellphone in years. I know that sounds strange coming from an IT guy but my logic is sound: if you don’t have one your boss can’t call it. One of my colleagues is a big VoIP genius and he pointed out that by using a dial-out gateway and Telus’ one-number-unlimited feature it’s possible to have the equivalent of unlimited calling for $7 per month on a prepaid phone – plus the one-time cost of provisioning a phone number that forwards incoming calls back through the gateway (about $25). I’ve been horny for the newer android-based phones that are in circulation in the states but most of the ones I want don’t operate on the Canadian bands yet and/or it will take a long time before they are rolled out up here, thus I decided for unlimited calling at $7 a month I may as well settle for a cheap phone in the mean time. I decided to tack on $10/month unlimited web browsing because it makes the e-mail and instant messaging packages moot.

The Keybo 2 is the closest thing to a smart phone in Telus’ prepaid lineup, and at the time of writing the most expensive – clocking in at a modest $99. It sports a 160x96px external screen and flips open to reveal a large QWERTY keyboard and 320x240px internal screen. There are stereo speakers mounted on either side of the internal screen and to be perfectly frank they are better sounding than my laptop’s. The Keybo 2 has a 3.2MP flash camera that takes decent pictures but crappy closeups.

In the United States (and possibly elsewhere) the Keybo 2 is marketed as the enV3. The Canadian model number is CX9200 and the US model is VX9200; as far as I can tell the difference is cosmetic. Verizon seems to be the main carrier for enVs in the states and Koodo is popular in Canada as well. Interestingly the Koodo and Verizon firmwares of the phone do not include Java support. It would seem that the popular thing to do with your Keybo is flash it to Telus’ firmware if you’re on a different provider. Unfortunately Telus’ firmware is so locked down that one wonders just how bad Verizon’s could be.

I’ve had a hell of a time over the past few days trying to find information on hacking the Keybo 2, most of the results I have found thus far only apply to the original Keybo (aka enV2 or VX9100), for example it no longer seems possible to simply overwrite application slots with other java apps to install them on the phone. Telus’ proxy prevents users from downloading apps from the web that don’t come from their store. I have tried altering the proxy settings to use a personal proxy on ports 8118, 80 and 110 but the browser fails to connect. I even tried popping the opera mini .jad and .jar files onto an SSL site and altering the .jad to pull from the new URL to no avail – the download begins, posts, then returns this error:

Issue has been reported.
Please try again later.

950 Server Error (-1289)

then the browser bounces back to the Telus apps store. I tried renaming the .jar to .jax (and updating the .jad accordingly) also to no avail.  I am beginning to suspect that the firmware has been modified to enforce some sort of DRM for applications. Custom ringtones are a pain in the ass as they definitely require DRM, fortunately they can be dropped into the phone’s filesystem at /brew/shared/ringtone/ with BitPim (1.0.7+ supports the CX9200) and given DRM with the Sony-Ericsson DRM Packager.

I couldn’t find the right SPC code for my particular phone anywhere (unlike the old Keybo/enV2 it does not have nvm_XXXX files) so I had to grab it with CDMA Workshop (it’s 105495 by the way). With the correct SPC you can access the programming menus for your phone by dialing:

##DEBUG
##TELUS
##BROWSER
##TEST
##DATA

Note that you can get into ##DEBUG on any LG phone with the unlock code 183729.

Overall, this phone pisses me off because it could do so much more but Telus makes it extremely difficult to modify. While there is some community support for the Keybo/enV2 those of us with the new Keybo 2s and enV3s are practically on our own at present time. The fact that the Telus firmware is considered “the good firmware” is extremely discouraging, flashing your old Verizon enV2 to Telus’ old Keybo firmware may let you load on some java apps but how to do this successfully on the newer Keybo 2′s firmware is as yet a mystery.