New(er) linux tracing tools

Came across an interesting video on reddit about some newer linux tracing tools. I think I’ve mentioned perf before, but this also covers ftrace (which apparently has been around for years) and the newer bpf.


Vsphere console on linux

The web console wasn’t working for me today. I downloaded the vmrc bundle, but that didn’t seem to install either. After a bit of messing around I brute forced it

  1. Looking at /tmp/vmware-root/vmware-vmis-10550.log showed the install was failing trying to load /usr/lib/vmware-installer/1.6/sopython/ . /usr/lib/vmware-installer didn’t exist.
  2. Ran the script to find the commands to get the binary data.
    bash -x VMware-Remote-Console-9.0.0-4288332.x86_64.bundle
  3. Decompressed the binary data with the commands from above
    dd if=VMware-Remote-Console-9.0.0-4288332.x86_64.bundle ibs=15156 obs=1024 skip=1 of=1.gz
    gzip -d 1.gz
    tar xvf 1
  4. Move the resulting directory to the right place
    mkdir -p /usr/lib/vmware-installer/1.6
    mv ~rjb/tmp/install/vmware-installer /usr/lib/vmware-installer/1.6
  5. Run installer
    bash ~rjb/tmp/VMware-Remote-Console-9.0.0-4288332.x86_64.bundle --console

Changing audio pitch in a video

I managed to end up with a few videos that had incorrect audio pitch. At first I thought the video speed was incorrect, but the time and play rate of the video seemed fine. After a little searching I came across a solution.

  1. Split source into separate video and audio files (various distros use ffmpeg or avconv)
    ffmpeg -i  -vcodec copy -an 1.mp4
    ffmpeg -i  1.wav
  2. Change audio pitch (install rubberband-cli, could also use audacity or similar). Experiment with the pitch shift (-p option), negative shifts down, positive up.
    rubberband -p -2 1.wav 1a.wav
  3. Recombine into a single file
    ffmpeg -i 1.mp4 -i 1a.wav -vcodec copy -strict experimental out.m4v


for i in *.m4v
 do avconv -i "$i" -vcodec copy -an 1.mp4
 avconv -i "$i" 1.wav
 rubberband -p -2 1.wav 1a.wav
 avconv -i 1.mp4 -i 1a.wav -vcodec copy -strict experimental out/"$i"
 rm -f 1.mp4 1.wav 1a.wav

Davmail and o365

So, we’re moving to office 365 soon. Due to various political issues, they’re going to have imap disabled, but ews will be on, so I should be able to use davmail. The following worked with my test account

  • davmail settings
Protocol = EWS
  • mutt settings
set imap_user=test-incloud@<domain>
set folder=imap://test-incloud@<domain>@localhost:1143
set spoolfile=imap://localhost:1143/INBOX
set record=imap://localhost:1143/Sent
set postponed=imaps://localhost:1143/Drafts

set smtp_url=smtp://test-incloud@<domain>@localhost:1025

ipmi security (or lack thereof)

Great talk by Matthew Garrett on the insecurity of ipmi. A number of security issues including

* Upgrade your BMC firmwares!
* Ensure cipher 0 is disabled on all BMCs (only requires valid username, not password!)
* Filter all incoming ipmi on the network (if BMC nic is unplugged ipmi will dhcp on the main interface)


Some notes on strace

I’ve been meaning to write a little on strace for a while. I use it fairly often, but as with everything it seems that there’s always a lot more to learn.


I was reading about a new perl module, Devel::Trace::Syscall which can be used as a perl debugger module to print stack traces when certain syscalls occur (perl -d:Trace::Syscall=$ARGS $SCRIPT).

There are a few more nice strace blogs posts by Julia Evans. One of the ideas I’d not thought of before is using the -c option (count call time) to assist with troubleshooting performance (which is mentioned here among other places.