Author: Baab

Starting around 1830 eastern in our Discord. Some of us will be at Shmoocon, so if you’re planning to be there as well, pop in and say hey!

So maybe you’re in Nova and have been craving one of these meetups, but maybe you’ve been busy, or maybe you’ve been battling your social anxiety, or maybe you’ve been having pressing issues at home, or maybe you’re wearing an ankle monitor.

Whoever you are, and whatever brings you to our meetup, you are invited, and welcome. We’ll be at Social House in Chantilly. Look for the group of tired, jaded tech folks, probably mostly dressed in black, and probably mostly drinking. Maybe I’ll bring some swag to reward anyone brave enough to join us.

There’s a Dairy Queen across the parking lot if that sways you. Official meetup time is 1830 eastern, but some show up earlier, and some show up later. Come out. You deserve this. We deserve each other.

We’re giving away a couple of badges and a few other soldery trinkets for new year’s.

Enter by following our YouTube. We’ll choose at random on New Year’s Eve (hell, maybe even live!) from the email connected to your youtube follower account and notify you there.

Content is becoming more frequent. PCB design classes, modular synth explorations, and who knows what we’ll get into in 2023? Follow and stay tuned!

https://www.youtube.com/@dc5402

The basement will be open to regulars & trusted friends on Monday 12/26 for our regular Monday meeting. I’ll open up the Discord channel for those who can’t make it. I’m feeling a bit like celebrating.

We’re part of the FIOS outage, apparently.

So I managed to find a satisfactory and effective resolution to my problem with serial number 0123456789ABCDEF. If you recall, the problem is that certain consumer-grade USB devices ship with non-unique serial numbers, making it difficult to use them with USB pass-through under VirtualBox.

• Serial number on multiple devices = 0123456789ABCDEF
• VirtualBox USB filtering (permanently mapping a device to a specific VM) relies a unique field. With diverse devices, this can be the vendor/product ID. With normal devices with unique serial numbers, the serial number can be used in the filters.
• With identical product, vendor and serial numbers, you’re stuck with “Port,” which at least in CentOS/Rocky’s USB subsystem, is dynamically assigned when the device is plugged in to the host. Example: Plug in a device, it shows up on Bus 001, Device 005. Unplug it, plug it back in, and it’s now on Bus 001, Device 006.
• Allegedly, udev rules can be set to assign a specific port (or a port “nickname”) using some other unique identifier, like the actual physical port the device is connected to. Still less than ideal, since that would require adherence to a strict protocol of unplugging and plugging into the same port. Anyway, I couldn’t get that to work.

So I dug around a bit, and found that the devices DO have a unique component — the device’s MAC address. It’s visible when using lsusb in verbose mode. But VirtualBox can’t see it, and it’s not an option in the VirtualBox filtering.

So what I ended up doing was abandoning VirtualBox’s USB filtering entirely.

I created a text file mapping those MAC addresses to VMs. Then I created a script which iterates through LSUSB, and checks the MAC addresses of every USB device it finds through that mapping file. When it finds one, it needs two things to make the usb attachment happen via command line. It needs either the UUID or machine name of the VM, and it needs the UUID or “address” of the USB device. My mapping file stores the MAC address of the device (discovered via lsusb) and the UUID of the VM, which is available via vboxmanage list vms.

The UUID of the USB device can be found by comparing the Bus and Port values found in lsusb to the output of vboxmanage list usbhost. With creative use of bash and awk, I was able to iterate through the devices, determine which ones are assigned to VMs, check to see if they’re currently attached, and if not, issue the vboxmanage controlvm vm-uuid usbattach usb-uuid command to attach the device to its home VM. So in case of a host reboot or someone rejiggering ports, a single command is enough to get things back where they belong.

I realize that there are probably only three people on the planet who have run into this particular problem, but I thought the solution was an interesting exercise in information-gathering on a VirtualBox host on a Rocky Linux platform, so I felt i was worth sharing.