Tag Archives: bash

Self-Signing Modules on Fedora 20

August 12, 2014 kit Leave a comment

I recently got a new computer for work. So new that the wireless drivers are not yet included in the kernel mainline, though they do exist in the staging tree in the main branch. It’s relatively easy to compile the module following the directions post on this blog post:
http://www.linlap.com/asus_transformer_book_trio_tx201la

Updated kernel source for 3.15:
https://kernel.googlesource.com/pub/scm/linux/kernel/git/next/linux-next.git/+archive/v3.15/drivers/staging/rtl8821ae.tar.gz

Makefile append:
KDIR := /lib/modules/$(shell uname -r)/build PWD := $(shell pwd) default: $(MAKE) -C $(KDIR) SUBDIRS=$(PWD) CONFIG_R8821AE=m modules

Basically you download that tarball, append to the Makefile, and run make. Simple.

The problem I ran into is that UEFI SecureBoot is set up, meaning that all code inserted in the kernel needs to be signed and recognized by the bios. It’s really not obvious how to do this, I guess because people are not really encouraged to build custom modules and kernels. I did eventually find a post from the SystemTap guy on how to do it:
http://sourceware.org/systemtap/wiki/SecureBoot

x509.genkey openssl config file
[ req ] default_bits = 4096 distinguished_name = req_distinguished_name prompt = no string_mask = utf8only x509_extensions = myexts


[ req_distinguished_name ]

CN = Modules

[ myexts ] basicConstraints=critical,CA:FALSE keyUsage=digitalSignature subjectKeyIdentifier=hash authorityKeyIdentifier=keyid

Creating the x509 certs, and adding them to MoK (machine-owner keys):
openssl req -new -nodes -utf8 -sha256 -days 36500 -batch -x509 -config x509.genkey -outform DER -out signing_key.x509 -keyout signing_key.priv sudo mokutil --import signing_key.x509 reboot

Sign modules and install:
/usr/src/kernels/`uname -r`/scripts/sign-file sha512 signing_key.priv signing_key.x509 rtl8821ae.ko sudo cp rtl8821ae.ko /lib/modules/3.16.0-1.fc22.x86_64/kernel/drivers/staging/rtl8821ae/

It kernel panic’d the first time (oops). The second time it ran ok.

Fuxing with video: Replace audio, add watermark

July 31, 2014 kit Leave a comment

# cut the video to match the time of the audio ffmpeg -i input.mp4 -ss 0 -t -strict -2 output.mp4


# replace the audio

ffmpeg -i input.mp4 -i input.mp3 -map 0:0 -map 1 -vcodec copy -acodec copy output.mp4
# adding an overlay to the video, replace the 0:0 with x:y coords

ffmpeg -y -i input.mp4 -i image.png -filter_complex 'overlay=0:0' -strict -2 output.mp4

Rotoscoping with autotrace and inkscape

July 23, 2014 kit Leave a comment

From http://kansenzone.blogspot.com/2008/05/automatic-rotoscoping.html

autotrace file.jpg -output-format svg -color-count 10 -despeckle-level 20 -filter-iterations 10 > file.svg

Exploding, compositing, reanimating gifs

July 22, 2014 kit Leave a comment

# -coalesce makes sure that each individual frame is complete convert animated.gif -coalesce frame%05d.png


# compose and flatten frames

for x in frame*.png; do convert -page +0+0 base.png -page +200+10 $x -flatten +repage comp-`basename $x`; done
# get frame delays

identify -verbose animated.gif |grep Delay|sed 's/.* \([0-9]*\)x.*/\1/' > delays
# generate convert command from the delays

$( echo -n convert; i=0; for d in `cat delays`; do printf " -delay $d comp-frame000%02d.png " $i; let i++; done; echo " out.gif" )

Sending Crash Sysrq Keystroke to KVM

July 17, 2014 kit Leave a comment

virsh send-key guest1 KEY_LEFTALT KEY_SYSRQ KEY_C

Testing links to see if they work

July 11, 2014 kit Leave a comment

The input is a csv where the first column is the URL you want to test. The curl line spits out the response code. -f means curl will return an exit code if the fetch fails.

# test URLs for x in $(cat "$file" | grep -v URL | cut -d, -f1) ; do code=$(curl -s -w %{response_code} -f "$x" -o /dev/null) && echo "URL OK $code: $x"; done

# convert URLs to nginx redirects sed -e 's#^http://[^/]*$/[^,]*$,$.*$$#rewrite ^\1$ \2 permanent;#' < "$file" > /tmp/output_redirects

Good times.

Kit Westneat