Category: Geekery

A few weeks ago I got seriously pissed off about all the things that were broken on my Linux box, not least the fact that since the last time I upgraded Ubuntu the program “aptitude” kept telling me that I had to uninstall several hundred packages, including some that looked like majorly important ones, so I bit the bullet and did a fresh install of Kubuntu 12.04. The fresh install went ok, the usual few glitches and things that needed to be reconfigured. But then almost as soon as I got all that sorted out, I got a notification that Kubuntu 12.10 was out. And I figured that since I hadn’t done all that much since installing it, an upgrade would probably be no sweat.

My first indication of trouble was after it rebooted – I got a “grub rescue” prompt, and bugger all else. I tried a few things that are supposed to allow you to put in your boot partition and boot, but none of them worked. So I hauled out the CD I’d used to install Kubuntu 12.04 and booted into rescue mode. I mounted all the partitions, did a grub_install /dev/sda and rebooted, and I was back in business.

The second problem was that none of our laptops could print to the print queue that is shared out by the Linux box. I had made sure that the CUPS config files hadn’t changed, but evidently that wasn’t enough. I got the two Mac laptops printing to it by “changing” them from ipp to ipps print queues. (I should mention that neither Macs nor Windows boxes actually let you look at the existing print queue and change things like the URL). On the Windows box, I think what I had to do was change the print queue from using the name “PSC_1500_series” to “PSC-1500-series”. No idea what else I changed (because of the aforementioned problem seeing how you defined it already) but I think that was it.

The third problem was worse – this morning I got an email from somebody who reads his email on my box saying he hadn’t gotten any email since the upgrade. I looked in the mail log, and what I could see is that the local deliver program had been changed from procmail to /usr/lib/dovecot/deliver -c /etc/dovecot/conf.d/01-mail-stack-delivery.conf -m "${EXTENSION}" That was an extreme WTF moment. Further investigation revealed that this config file specified maildir instead of mbox. I just changing it to mbox, but then it complained that it didn’t have permission to write to /var/mail/ptomblin. I couldn’t find an option to tell this deliver program to run setgrp to mail. I also discovered that something had screwed up my postfix configuration to add this local delivery option, and also remove a bunch of my spam protection checks. So I removed the mail-stack-delivery package and the postfix-dovecot package, and restored all the config files. Things seem to be working again. And I used the formail command to process all the files in the various people’s “maildirs” and put them back in their mboxes.

My next trial and tribulation is that my hourly backup program, which uses lvm snapshots and rsync, is intermittently screwing up. Sometimes it can’t unmount the snapshot partition, and sometimes it can’t remove it (with the message Unable to deactivate open lvm2-home-real (252:12), and sometimes it just fails for no reason. I know there are a ton of race conditions in lvm snapshot stuff, so I already had a “sleep 10” after the lvremove. I added another one after the umount that preceeds the lvremove, in case umount suddenly got lazy and the reason it’s failing is that it hasn’t finished unmounting the partition. That seems to have quelled the major problems, but the lvremove command is spitting out the message /sbin/dmeventd: stat failed: No such file or directory and I need to figure out how to suppress that so I don’t get emailed every hour.

Yesterday was a fun day in the continuing struggle against IE brokenness.

First problem: the form submit button used to work on IE, but now it doesn’t. Well, no matter, because the form had an onsubmit that did some AJAXy stuff and then cancelled the form submit. Rather than wasting time trying to figure out why it works on real browsers and not on IE, I just changed the submit button into an ordinary button that invoked my function. Problem solved.

Second problem: My form is very dynamic, allowing you to add, delete or clone table rows, each of which contains several select, checkbox, and textarea input fields, all with associated onchange or onclick callbacks. The problem was that when you cloned a row, the callbacks on the new row would apply to the original row. All the callbacks had the row id in the arguments list, and when I clone I use the jquery attr command and a regular expression to change the row id. That works for real browsers, and it apparently works in IE (if you examine the code in Firebug you see the new id), but apparently the actual callback data is stored internally somewhere. It didn’t seem to matter whether I called clone with true or false in the copyData argument. So I restructured all my callbacks so the were activated by the jquery on command, and grabbed the row id and other arguments using the jQuery(this).parents('tr').

It was annoying to have to do all this stuff because IE is so different from real browsers, but the code is probably better for it.

Saw this one in the comment spam for this blog: (the name of the product and other details elided)

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