Vladimir Kotal vladak

Learning Rust gotchas

That is, learning from C99.

Basics

by default variables are constant. To make a variable mutable, it has to have the mut keyword:
- otherwise it would not compile

jetkvm/dc-extension-firmware#1

solution/workaround from https://discord.com/channels/1270105230989594634/1367610331806957699/1367624533598802011

Jared Jones — 02.05.25 0:11 Instructions to update your DC Extension to Power on by Default

Unplug everything from the DC extension and bring it over to your PC
Find a USB-C to USB-C (or) USB-A to USB-C cable and attach one end to your PC.

The OnScreen LG utility reports: (3.04, 0.12.16, 4.18)

After the update to macOS Sequoia 15.4, the display no longer worked as USB hub, rendering external keyboard connected directly to the display over USB useless. Had to unplug and replug the display power for this to work again.

Links:

For the home/end keys to work on external USB keyboard in macOS, it is necessary to set key bindings like so:

mkdir ~/Library/KeyBindings && touch ~/Library/KeyBindings/DefaultKeyBinding.dict
cat << EOF > ~/Library/KeyBindings/DefaultKeyBinding.dict
{
  "\UF729"  = moveToBeginningOfParagraph:; // home
  "\UF72B"  = moveToEndOfParagraph:; // end
  "$\UF729" = moveToBeginningOfParagraphAndModifySelection:; // shift-home
  "$\UF72B" = moveToEndOfParagraphAndModifySelection:; // shift-end
 "^\UF729" = moveToBeginningOfDocument:; // ctrl-home

context: JDK 21 support: oracle/opengrok#4459

existing PR from Lubos contains some of the changes: oracle/opengrok#4570

Specifically, all the URL() constructors are being deprecated in Java 21: https://docs.oracle.com/en/java/javase/21/docs/api//java.base/java/net/URL.html. The only way to get URL object is to create URI object first and then use toURL() method to convert it (the URL.of() static method requires URI argument).

Fun fact: URL can establish connection to the target using the openConnection() method (even via proxy).

My note: oracle/opengrok#4570 (comment):

I took a longer look at the departure from the URL() constructors yesterday. The URL class by itself does not support any encoding/decoding, it merely breaks down the URL into pieces. The encoding is then supplied by the URI class.

talk protocol

Here are my sparse notes on the BSD talk protocol. The goal was to arrive at understanding of the protocol.

Should update https://en.wikipedia.org/wiki/Talk_(software) with the info one day.

Demo/practical

Exstablish a talk session, observe the messages/syscalls.

Initial checks

Start by checking that there aren't any previous ssh keys inside the FIDO2 authenticator of your YubiKey. You can check if they exist by running the command below:

nix shell nixpkgs#yubikey-manager -c ykman fido credentials list

If the command above outputs a string mentioning "ssh" or "openssh", then you have already got a key generated and store on your YubiKey.

Evaluating additional authentication factors

Before generating a new ssh key to store on your YubiKey you must consider which additional required authentication factors you want to use. Below you can see a table with the available factors and their corresponding command:

Firstly, let's create a file of 512 bytes, i.e. matching the tar block size exactly, full of 'A' characters:

$ python3 -c 'print("A" * 512, end="")' > 512A.out

We can see that the length of the file is indeed 512 bytes and that the contents match our expectations:

$ ls -ld 512A.out

more notes for oracle/opengrok#4317

Using the code fixed to perform correct Path comparisons in both places (on the set of files from FileCollector as well as in IndexDatabase#processFileIncremental(), the script number 3 (oracle/opengrok#4317 (comment)) this still leads to cases with duplicate documents. This does not happen every time, it might be timing related.

The script goes through solaris-userland Git repository using particular sequence of changesets that were previously known to reproduce the duplicate documents (before the Path comparator fixes): 3b039b16f 170ebb43b 80cc6ae18 52c217090 a609ca278 69a8daead 07e01a4e6 154009177 794af3182 c073248f7 823f2c28e 4a5e3cb85 341f9beb2 653378bce 4f8fe9ee8

Changes to the code:

diff --git a/opengrok-indexer/src/main/java/org/opengrok/indexer/index/IndexDatabase.java b/opengrok-indexer/src/main/java/org/opengrok/indexer/index/IndexDat

	# SPDX-FileCopyrightText: 2023 anecdata
	#
	# SPDX-License-Identifier: MIT

	import json
	import microcontroller
	import supervisor

	from ⚙️ import *