• Student: anuragxone

• Student: Nikolaos

• Student: Nathan D

• Student: Sreehari Prasad TM

• Student: hanbings

• Student: xuantengh

• Student: Krysztal Huang

• I m trying to get back into bugs.debian.org administration, so I spent some time catching up on my owner@bugs.debian.org mailbox and answering a number of support requests there.
• I fixed a regression I d introduced last year where groff s PDF output had invalid date headers, both upstream and in Debian.
• I released man-db 2.12.1.
• openssh:
  • I did a little more testing of Luca Boccassi s modifications to upstream s inline systemd notification patch.
  • I did an extensive review of some of the choices in Debian s OpenSSH packaging, in light of last month s xz-utils backdoor.
  • I fixed a build failure on ppc64el, forwarded upstream.
  • I proposed reducing shared library linkage in tcp-wrappers; its maintainer accepted this by disabling NIS support.
  • I applied a suggestion to improve ordering of systemd services in relation to nss-user-lookup.target.
• I updated putty to 0.81.
• Python team:
  • I fixed build/autopkgtest failures in cytoolz (upstream PR), nbconvert (due to sphinx and lxml-html-clean changes), python-argcomplete, python-exceptiongroup, readability, toolz (upstream PR), and topplot.
  • I made a merge request to fix a build failure in pyferret.
  • I fixed a mistake in a Debian patch to python-ecdsa, noticed while updating jsonpickle.
  • I updated cachelib, dnsdiag, feedparser, jsonpickle, pywavelets (fixing a distutils dependency), python-aiohttp-session, python-avro, python-rstr, vine (including an upstream packaging tweak, and wtforms to new upstream versions.
• I did some inconclusive investigation of flaky tests in gcr4. More work is needed there.
• I proposed a patch for a build failure in gyoto, both upstream and in Debian.

• phosh: A Wayland shell for mobile devices
  • Release phosh 0.37.1
  • Release phosh 0.38.0
  • Be more generous in the gnome-session versions we support: Merge Request
  • Improve notification timestamps for translations: Merge Request
  • Improve test coverage a bit: Merge Request
  • Improve introspection data and documentation (Merge Request 1, Merge Request 2). Besides better docs (we now also fail on new warnings and errors (Merge Request) this allows to use parts of phosh in e.g. display managers in languages using introspection (Rust, JS, ). See this issue how this could become useful.
  • Add night light quick settings toggle: Merge Request
  • Fix power menu rendering without Cantarell: Merge Request
  • Track settings state (Merge Request) in shell state flags too. This will be useful to make tests more robust.
• phoc: A wlroots based Wayland compositor mostly used on mobile phones
  • More internal cleanup: Merge Request
  • Use shared gmobile: Merge Request
  • More introspection fixes to improve doc builds: Merge Request
  • Fix window cycle order: Merge Request
  • Fix crash with cutout/notch debug: Merge Request
• phosh-tour: A short introduction to Phosh
  • Fix blurry images: Merge Request
  • Fix flatpak build: Merge Request
  • Fix packaging build: Merge Request
  • Add a small Getting started page so phosh-tour has anything to point at
• gmobile: Functions useful in mobile related, glib based projects
  • Release 0.1.0
  • Update docs for shared lib use: Merge Request
  • Upload to Debian: https://packages.debian.org/sid/libgmobile0
• libcall-ui: Common user interface parts for call handling
  • Release 0.2.0: Merge Request
• calls: Phone calls application
  • Fix crash without location services: Merge Request
• phosh-ev: Monitor battery status of an electric car
  • Switch flatpak runtime to GNOME 46: Merge Request
• phosh-mobile-settings: Mobile specific settings
  • osk: Allow to configure whether to ignore hardware keyboards: Merge Request
  • Fix build without phoc: Merge Request
  • Allow to organise additional quick settings: Merge Request
• epiphany Don't make it appear frozen on first start: Merge Request
• iio-sensor-proxy (missed that one in March): Make test-suite more robust so people aren't puzzled when trying things locally: Merge Request
• mobile-broadband-provider-info Prepare Release: Merge Request
• feedbackd: A daemon to provide haptic, led and audio feedback triggered by application events
  • Allow to override feedback level: Merge Request (gnome-clocks branch using this)
  • Allow to use shared gmobile: Merge Request
  • Release 0.3.0: Merge Request
• meta-phosh Update dependency set: Merge Request Use common style check: Merge Request
• phosh nightly: Package builds of current Phosh git
  • Add some more packages that are useful for mobile: https://source.puri.sm/guido.gunther/phosh-debs
• livi: A small video player targeting mobile devices
  • Add devel profile to ease having the devel and release flatpak installed: Merge Request
• chatty / libcmatrix: Assorted fixes. Some to make matrix a bit more robust:
  • Don't forget to call sync callback: Merge Request
  • Improve copy popover: Merge Request
  • Drop support for libsoup2: Merge Request
  • Matrix robustness: Merge Request
  • Fix Matrix image download: Merge Request
  • Fix Doc build and make sure more methods end up there: Merge Request
• systemd:
  • Discuss hwdb and udev rules so we can track unidle/wakup keys: hwdb Merge Request, udev Merge Request to better handle device tree devices. As it turns out we'll do most of this in phoc initially and then open another merge request once we have more data.
• librem5-flash-image
  • Bring it back to debian testing: https://tracker.debian.org/pkg/librem5-flash-image

Me: Hi everyone, my name s Matt, and I m a mediocre programmer. Everyone: Hi, Matt. Facilitator: Are you an alcoholic, Matt? Me: No, not since I stopped reading Twitter. Facilitator: Then I think you re in the wrong room.

Neither a Borrower Nor a Lender Be If you know anything about Rust, you probably know about the dreaded borrow checker . It s the thing that makes sure you don t have two pieces of code trying to modify the same data at the same time, or using a value when it s no longer valid. While Rust s borrowing semantics allow excellent performance without compromising safety, for us mediocre programmers it gets very complicated, very quickly. So, the moment the compiler wants to start talking about explicit lifetimes , I shut it up by just using owned values instead. It s not that I never borrow anything; I have some situations that I know are borrow-safe for the mediocre programmer (I ll cover those later). But any time I m not sure how things will pan out, I ll go straight for an owned value. For example, if I need to store some text in a struct or enum, it s going straight into a String. I m not going to start thinking about lifetimes and &'a str; I ll leave that for smarter people. Similarly, if I need a list of things, it s a Vec<T> every time no &'b [T] in my structs, thank you very much.

Attack of the Clones Following on from the above, I ve come to not be afraid of .clone(). I scatter them around my code like seeds in a field. Life s too short to spend time trying to figure out who s borrowing what from whom, if I can just give everyone their own thing. There are warnings in the Rust book (and everywhere else) about how a clone can be expensive . While it s true that, yes, making clones of data structures consumes CPU cycles and memory, it very rarely matters. CPU cycles are (usually) plentiful and RAM (usually) relatively cheap. Mediocre programmer mental effort is expensive, and not to be spent on premature optimisation. Also, if you re coming from most any other modern language, Rust is already giving you so much more performance that you re probably ending up ahead of the game, even if you .clone() everything in sight. If, by some miracle, something I write gets so popular that the expense of all those spurious clones becomes a problem, it might make sense to pay someone much smarter than I to figure out how to make the program a zero-copy masterpiece of efficient code. Until then clone early and clone often, I say!

Derive Macros are Powerful Magicks If you start .clone()ing everywhere, pretty quickly you ll be hit with this error:

error[E0599]: no method named  clone  found for struct  Foo  in the current scope

This is because not everything can be cloned, and so if you want your thing to be cloned, you need to implement the method yourself. Well sort of. One of the things that I find absolutely outstanding about Rust is the derive macro . These allow you to put a little marker on a struct or enum, and the compiler will write a bunch of code for you! Clone is one of the available so-called derivable traits , so you add #[derive(Clone)] to your structs, and poof! you can .clone() to your heart s content. But there are other things that are commonly useful, and so I ve got a set of traits that basically all of my data structures derive:

#[derive(Clone, Debug, Default)]
struct Foo  
    // ...
 

Every time I write a struct or enum definition, that line #[derive(Clone, Debug, Default)] goes at the top. The Debug trait allows you to print a debug representation of the data structure, either with the dbg!() macro, or via the :? format in the format!() macro (and anywhere else that takes a format string). Being able to say what exactly is that? comes in handy so often, not having a Debug implementation is like programming with one arm tied behind your Aeron. Meanwhile, the Default trait lets you create an empty instance of your data structure, with all of the fields set to their own default values. This only works if all the fields themselves implement Default, but a lot of standard types do, so it s rare that you ll define a structure that can t have an auto-derived Default. Enums are easily handled too, you just mark one variant as the default:

#[derive(Clone, Debug, Default)]
enum Bar  
    Something(String),
    SomethingElse(i32),
    #[default]   // <== mischief managed
    Nothing,
 

Borrowing is OK, Sometimes While I previously said that I like and usually use owned values, there are a few situations where I know I can borrow without angering the borrow checker gods, and so I m comfortable doing it. The first is when I need to pass a value into a function that only needs to take a little look at the value to decide what to do. For example, if I want to know whether any values in a Vec<u32> are even, I could pass in a Vec, like this:

fn main()  
    let numbers = vec![0u32, 1, 2, 3, 4, 5];
    if has_evens(numbers)  
        println!("EVENS!");
     
 
fn has_evens(numbers: Vec<u32>) -> bool  
    numbers.iter().any( n  n % 2 == 0)
 

Howver, this gets ugly if I m going to use numbers later, like this:

fn main()  
    let numbers = vec![0u32, 1, 2, 3, 4, 5];
    if has_evens(numbers)  
        println!("EVENS!");
     
    // Compiler complains about "value borrowed here after move"
    println!("Sum:  ", numbers.iter().sum::<u32>());
 
fn has_evens(numbers: Vec<u32>) -> bool  
    numbers.iter().any( n  n % 2 == 0)
 

Helpfully, the compiler will suggest I use my old standby, .clone(), to fix this problem. But I know that the borrow checker won t have a problem with lending that Vec<u32> into has_evens() as a borrowed slice, &[u32], like this:

fn main()  
    let numbers = vec![0u32, 1, 2, 3, 4, 5];
    if has_evens(&numbers)  
        println!("EVENS!");
     
 
fn has_evens(numbers: &[u32]) -> bool  
    numbers.iter().any( n  n % 2 == 0)
 

The general rule I ve got is that if I can take advantage of lifetime elision (a fancy term meaning the compiler can figure it out ), I m probably OK. In less fancy terms, as long as the compiler doesn t tell me to put 'a anywhere, I m in the green. On the other hand, the moment the compiler starts using the words explicit lifetime , I nope the heck out of there and start cloning everything in sight. Another example of using lifetime elision is when I m returning the value of a field from a struct or enum. In that case, I can usually get away with returning a borrowed value, knowing that the caller will probably just be taking a peek at that value, and throwing it away before the struct itself goes out of scope. For example:

struct Foo  
    id: u32,
    desc: String,
 
impl Foo  
    fn description(&self) -> &str  
        &self.desc
     
 

Returning a reference from a function is practically always a mortal sin for mediocre programmers, but returning one from a struct method is often OK. In the rare case that the caller does want the reference I return to live for longer, they can always turn it into an owned value themselves, by calling .to_owned().

Avoid the String Tangle Rust has a couple of different types for representing strings String and &str being the ones you see most often. There are good reasons for this, however it complicates method signatures when you just want to take some sort of bunch of text , and don t care so much about the messy details. For example, let s say we have a function that wants to see if the length of the string is even. Using the logic that since we re just taking a peek at the value passed in, our function might take a string reference, &str, like this:

fn is_even_length(s: &str) -> bool  
    s.len() % 2 == 0
 

That seems to work fine, until someone wants to check a formatted string:

fn main()  
    // The compiler complains about "expected  &str , found  String "
    if is_even_length(format!("my string is  ", std::env::args().next().unwrap()))  
        println!("Even length string");
     
 

Since format! returns an owned string, String, rather than a string reference, &str, we ve got a problem. Of course, it s straightforward to turn the String from format!() into a &str (just prefix it with an &). But as mediocre programmers, we can t be expected to remember which sort of string all our functions take and add & wherever it s needed, and having to fix everything when the compiler complains is tedious. The converse can also happen: a method that wants an owned String, and we ve got a &str (say, because we re passing in a string literal, like "Hello, world!"). In this case, we need to use one of the plethora of available turn this into a String mechanisms (.to_string(), .to_owned(), String::from(), and probably a few others I ve forgotten), on the value before we pass it in, which gets ugly real fast. For these reasons, I never take a String or an &str as an argument. Instead, I use the Power of Traits to let callers pass in anything that is, or can be turned into, a string. Let us have some examples. First off, if I would normally use &str as the type, I instead use impl AsRef<str>:

fn is_even_length(s: impl AsRef<str>) -> bool  
    s.as_ref().len() % 2 == 0
 

Note that I had to throw in an extra as_ref() call in there, but now I can call this with either a String or a &str and get an answer. Now, if I want to be given a String (presumably because I plan on taking ownership of the value, say because I m creating a new instance of a struct with it), I use impl Into<String> as my type:

struct Foo  
    id: u32,
    desc: String,
 
impl Foo  
    fn new(id: u32, desc: impl Into<String>) -> Self  
        Self   id, desc: desc.into()  
     
 

We have to call .into() on our desc argument, which makes the struct building a bit uglier, but I d argue that s a small price to pay for being able to call both Foo::new(1, "this is a thing") and Foo::new(2, format!("This is a thing named name ")) without caring what sort of string is involved.

Always Have an Error Enum Rust s error handing mechanism (Results everywhere), along with the quality-of-life sugar surrounding it (like the short-circuit operator, ?), is a delightfully ergonomic approach to error handling. To make life easy for mediocre programmers, I recommend starting every project with an Error enum, that derives thiserror::Error, and using that in every method and function that returns a Result. How you structure your Error type from there is less cut-and-dried, but typically I ll create a separate enum variant for each type of error I want to have a different description. With thiserror, it s easy to then attach those descriptions:

#[derive(Clone, Debug, thiserror::Error)]
enum Error  
    #[error(" 0  caught fire")]
    Combustion(String),
    #[error(" 0  exploded")]
    Explosion(String),
 

I also implement functions to create each error variant, because that allows me to do the Into<String> trick, and can sometimes come in handy when creating errors from other places with .map_err() (more on that later). For example, the impl for the above Error would probably be:

impl Error  
    fn combustion(desc: impl Into<String>) -> Self  
        Self::Combustion(desc.into())
     
    fn explosion(desc: impl Into<String>) -> Self  
        Self::Explosion(desc.into())
     
 

It s a tedious bit of boilerplate, and you can use the thiserror-ext crate s thiserror_ext::Construct derive macro to do the hard work for you, if you like. It, too, knows all about the Into<String> trick.

Banish map_err (well, mostly) The newer mediocre programmer, who is just dipping their toe in the water of Rust, might write file handling code that looks like this:

fn read_u32_from_file(name: impl AsRef<str>) -> Result<u32, Error>  
    let mut f = File::open(name.as_ref())
        .map_err( e  Error::FileOpenError(name.as_ref().to_string(), e))?;
    let mut buf = vec![0u8; 30];
    f.read(&mut buf)
        .map_err( e  Error::ReadError(e))?;
    String::from_utf8(buf)
        .map_err( e  Error::EncodingError(e))?
        .parse::<u32>()
        .map_err( e  Error::ParseError(e))
 

This works great (or it probably does, I haven t actually tested it), but there are a lot of .map_err() calls in there. They take up over half the function, in fact. With the power of the From trait and the magic of the ? operator, we can make this a lot tidier. First off, assume we ve written boilerplate error creation functions (or used thiserror_ext::Construct to do it for us)). That allows us to simplify the file handling portion of the function a bit:

fn read_u32_from_file(name: impl AsRef<str>) -> Result<u32, Error>  
    let mut f = File::open(name.as_ref())
        // We've dropped the  .to_string()  out of here...
        .map_err( e  Error::file_open_error(name.as_ref(), e))?;
    let mut buf = vec![0u8; 30];
    f.read(&mut buf)
        // ... and the explicit parameter passing out of here
        .map_err(Error::read_error)?;
    // ...

If that latter .map_err() call looks weird, without the e and such, it s passing a function-as-closure, which just saves on a few characters typing. Just because we re mediocre, doesn t mean we re not also lazy. Next, if we implement the From trait for the other two errors, we can make the string-handling lines significantly cleaner. First, the trait impl:

impl From<std::string::FromUtf8Error> for Error  
    fn from(e: std::string::FromUtf8Error) -> Self  
        Self::EncodingError(e)
     
 
impl From<std::num::ParseIntError> for Error  
    fn from(e: std::num::ParseIntError) -> Self  
        Self::ParseError(e)
     
 

(Again, this is boilerplate that can be autogenerated, this time by adding a #[from] tag to the variants you want a From impl on, and thiserror will take care of it for you) In any event, no matter how you get the From impls, once you have them, the string-handling code becomes practically error-handling-free:

    Ok(
        String::from_utf8(buf)?
            .parse::<u32>()?
    )

The ? operator will automatically convert the error from the types returned from each method into the return error type, using From. The only tiny downside to this is that the ? at the end strips the Result, and so we ve got to wrap the returned value in Ok() to turn it back into a Result for returning. But I think that s a small price to pay for the removal of those .map_err() calls. In many cases, my coding process involves just putting a ? after every call that returns a Result, and adding a new Error variant whenever the compiler complains about not being able to convert some new error type. It s practically zero effort outstanding outcome for the mediocre programmer.

Just Because You re Mediocre, Doesn t Mean You Can t Get Better To finish off, I d like to point out that mediocrity doesn t imply shoddy work, nor does it mean that you shouldn t keep learning and improving your craft. One book that I ve recently found extremely helpful is Effective Rust, by David Drysdale. The author has very kindly put it up to read online, but buying a (paper or ebook) copy would no doubt be appreciated. The thing about this book, for me, is that it is very readable, even by us mediocre programmers. The sections are written in a way that really clicked with me. Some aspects of Rust that I d had trouble understanding for a long time such as lifetimes and the borrow checker, and particularly lifetime elision actually made sense after I d read the appropriate sections.

Finally, a Quick Beg I m currently subsisting on the kindness of strangers, so if you found something useful (or entertaining) in this post, why not buy me a refreshing beverage? It helps to know that people like what I m doing, and helps keep me from having to sell my soul to a private equity firm.

• [1] https://etbe.coker.com.au/2023/10/29/hello-kitty/

1. Voice input for dictation
2. Voice assistant like Google/Apple
3. Voice output
4. Full operation for visually impaired people

• [1] https://etbe.coker.com.au/2024/03/13/shape-computers/
• [2] https://www.youtube.com/watch?v=TitZV6k8zfA
• [3] https://etbe.coker.com.au/2023/10/11/pinephone-status/
• [4] https://wiki.debian.org/MobileApps
• [5] https://www.youtube.com/watch?v=0O2yTG3n1Vc
• [6] https://etbe.coker.com.au/2023/05/29/considering-convergence/
• [7] https://etbe.coker.com.au/2024/04/26/convergence-vs-transference/

Changes in RQuantLib version 0.4.22 (2024-04-25)

• Small code cleanup removing duplicate R code
• Small improvements to C++ compilation flags
• Robustify internal version comparison to accommodate RC releases
• Adjustments to two C++ files for QuantLib 1.34

This post by Dirk Eddelbuettel originated on his Thinking inside the box blog. Please report excessive re-aggregation in third-party for-profit settings.

 
  description = "Haskell dev MicroVM";
  inputs.impermanence.url = "github:nix-community/impermanence";
  inputs.microvm.url = "github:astro/microvm.nix";
  inputs.microvm.inputs.nixpkgs.follows = "nixpkgs";
  outputs =   self, impermanence, microvm, nixpkgs  :
    let
      persistencePath = "/persistent";
      system = "x86_64-linux";
      user = "thk";
      vmname = "haskell";
      nixosConfiguration = nixpkgs.lib.nixosSystem  
          inherit system;
          modules = [
            microvm.nixosModules.microvm
            impermanence.nixosModules.impermanence
            ( pkgs, ...  :  
            environment.persistence.$ persistencePath  =  
                hideMounts = true;
                users.$ user  =  
                  directories = [
                    "git" ".stack"
                  ];
                 ;
               ;
              environment.sessionVariables =  
                TERM = "screen-256color";
               ;
              environment.systemPackages = with pkgs; [
                ghc
                git
                (haskell-language-server.override   supportedGhcVersions = [ "94" ];  )
                htop
                stack
                tmux
                tree
                vcsh
                zsh
              ];
              fileSystems.$ persistencePath .neededForBoot = nixpkgs.lib.mkForce true;
              microvm =  
                forwardPorts = [
                    from = "host"; host.port = 2222; guest.port = 22;  
                    from = "guest"; host.port = 5432; guest.port = 5432;   # postgresql
                ];
                hypervisor = "qemu";
                interfaces = [
                    type = "user"; id = "usernet"; mac = "00:00:00:00:00:02";  
                ];
                mem = 4096;
                shares = [  
                  # use "virtiofs" for MicroVMs that are started by systemd
                  proto = "9p";
                  tag = "ro-store";
                  # a host's /nix/store will be picked up so that no
                  # squashfs/erofs will be built for it.
                  source = "/nix/store";
                  mountPoint = "/nix/.ro-store";
                   
                  proto = "virtiofs";
                  tag = "persistent";
                  source = "~/.local/share/microvm/vms/$ vmname /persistent";
                  mountPoint = persistencePath;
                  socket = "/run/user/1000/microvm-$ vmname -persistent";
                 
                ];
                socket = "/run/user/1000/microvm-control.socket";
                vcpu = 3;
                volumes = [];
                writableStoreOverlay = "/nix/.rwstore";
               ;
              networking.hostName = vmname;
              nix.enable = true;
              nix.nixPath = ["nixpkgs=$ builtins.storePath <nixpkgs> "];
              nix.settings =  
                extra-experimental-features = ["nix-command" "flakes"];
                trusted-users = [user];
               ;
              security.sudo =  
                enable = true;
                wheelNeedsPassword = false;
               ;
              services.getty.autologinUser = user;
              services.openssh =  
                enable = true;
               ;
              system.stateVersion = "24.11";
              systemd.services.loadnixdb =  
                description = "import hosts nix database";
                path = [pkgs.nix];
                wantedBy = ["multi-user.target"];
                requires = ["nix-daemon.service"];
                script = "cat $ persistencePath /nix-store-db-dump nix-store --load-db";
               ;
              time.timeZone = nixpkgs.lib.mkDefault "Europe/Berlin";
              users.users.$ user  =  
                extraGroups = [ "wheel" "video" ];
                group = "user";
                isNormalUser = true;
                openssh.authorizedKeys.keys = [
                  "ssh-rsa REDACTED"
                ];
                password = "";
               ;
              users.users.root.password = "";
              users.groups.user =  ;
             )
          ];
         ;
    in  
      packages.$ system .default = nixosConfiguration.config.microvm.declaredRunner;
     ;
 

[Unit]
Description=MicroVM for Haskell development
Requires=microvm-virtiofsd-persistent@.service
After=microvm-virtiofsd-persistent@.service
AssertFileNotEmpty=%h/.local/share/microvm/vms/%i/flake/flake.nix
[Service]
Type=forking
ExecStartPre=/usr/bin/sh -c "[ /nix/var/nix/db/db.sqlite -ot %h/.local/share/microvm/nix-store-db-dump ]   nix-store --dump-db >%h/.local/share/microvm/nix-store-db-dump"
ExecStartPre=ln -f -t %h/.local/share/microvm/vms/%i/persistent/ %h/.local/share/microvm/nix-store-db-dump
ExecStartPre=-%h/.local/state/nix/profile/bin/tmux new -s microvm -d
ExecStart=%h/.local/state/nix/profile/bin/tmux new-window -t microvm: -n "%i" "exec %h/.local/state/nix/profile/bin/nix run --impure %h/.local/share/microvm/vms/%i/flake"

[Unit]
Description=serve host persistent folder for dev VM
AssertPathIsDirectory=%h/.local/share/microvm/vms/%i/persistent
[Service]
ExecStart=%h/.local/state/nix/profile/bin/virtiofsd \
 --socket-path=$ XDG_RUNTIME_DIR /microvm-%i-persistent \
 --shared-dir=%h/.local/share/microvm/vms/%i/persistent \
 --gid-map :995:%G:1: \
 --uid-map :1000:%U:1:

• 2023-08-28, OSNews: The end of the Googleverse
• 2023-07-28, Cory Doctorow: Microincentives and Enshittification
• 2023-10-03, Cory Doctorow: Google s enshittification memos
• 2024-01-15, Tim Bray: Mourning Google

• More people are searching for alternatives to Google.
• Mainstream hard discs are incredibly big.
• Mainstream internet connection is incredibly fast.
• Google is bleeding talent.
• Most of the building blocks are available as free software.
• Success depends on your definition

A mildly technical computer user (able to install software) has access to a search engine that provides them with superior search results compared to Google for at least a few predefined areas of interest.

• learn about nix
• install software that might not be available in Debian
• install software without root access
• declare software necessary for a user s environment inside $HOME/.config

with (import <nixpkgs>  );
 
  packageOverrides = pkgs: with pkgs;  
    thk-emacsWithPackages = (pkgs.emacsPackagesFor emacs-gtk).emacsWithPackages (
      epkgs:
      (with epkgs.elpaPackages; [
        ace-window
        company
        org
        use-package
      ]) ++ (with epkgs.melpaPackages; [
        editorconfig
        flycheck
        haskell-mode
        magit
        nix-mode
        paredit
        rainbow-delimiters
        treemacs
        visual-fill-column
        yasnippet-snippets
      ]) ++ [    # From main packages set
      ]
    );

    userPackages = buildEnv  
      extraOutputsToInstall = [ "doc" "info" "man" ];
      name = "user-packages";
      paths = [
        ghc
        git
        (pkgs.haskell-language-server.override   supportedGhcVersions = [ "94" ];  )
        nix
        stack
        thk-emacsWithPackages
        tmux
        vcsh
        virtiofsd
      ];
     ;
   ;
 

nix-env --install --attr nixpkgs.userPackages --remove-all

[Service]
ExecStart=
ExecStart=@/home/thk/.local/state/nix/profile/bin/nix-daemon nix-daemon --daemon

Something went wrong, please try again later.

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GTK file chooser image preview size should be configurable The file chooser that appears when uploading a file (e.g. an image to Google Fotos) learned to show a preview in issue 15500. The preview image size is hard coded to 256x512 in kPreviewWidth and kPreviewHeight in ui/gtk/select_file_dialog_linux_gtk.cc. Please make the size configurable. On high DPI screens the images are too small to be of much use.

git clone https://gitlab.com/gsasl/libntlm.git
cd libntlm
git checkout v1.8
./bootstrap
./configure
make distcheck
gpg -b libntlm-1.8.tar.gz

make srcdist
gpg -b libntlm-1.8-src.tar.gz

91de864224913b9493c7a6cec2890e6eded3610d34c3d983132823de348ec2ca  libntlm-1.8-src.tar.gz
ce6569a47a21173ba69c990965f73eb82d9a093eb871f935ab64ee13df47fda1  libntlm-1.8.tar.gz

podman run -it --rm ubuntu:22.04
apt-get update
apt-get install -y --no-install-recommends autoconf automake libtool make git ca-certificates
git clone https://gitlab.com/gsasl/libntlm.git
cd libntlm
git checkout v1.8
./bootstrap
./configure
make dist srcdist
sha256sum libntlm-*.tar.gz

podman run -it --rm almalinux:8
dnf update -y
dnf install -y make wget gcc
wget https://download.savannah.nongnu.org/releases/libntlm/libntlm-1.8.tar.gz
tar xfa libntlm-1.8.tar.gz
cd libntlm-1.8
./configure
make dist
sha256sum libntlm-1.8.tar.gz

podman run -it --rm debian:11
apt-get update
apt-get install -y --no-install-recommends make git ca-certificates
git clone https://gitlab.com/gsasl/libntlm.git
cd libntlm
git checkout v1.8
make -f cfg.mk srcdist
sha256sum libntlm-1.8-src.tar.gz 

podman run -it --rm docker.io/kpengboy/trisquel:11.0
apt-get update
apt-get install -y --no-install-recommends autoconf automake libtool make wget git ca-certificates
wget https://download.savannah.nongnu.org/releases/libntlm/libntlm-1.8-src.tar.gz
tar xfa libntlm-1.8-src.tar.gz
cd libntlm-v1.8
./bootstrap
./configure
make dist
sha256sum libntlm-1.8.tar.gz

git archive --prefix=libntlm-v1.8/ -o libntlm-v1.8.tar.gz HEAD

Back to the Future Time to admit something. I really love Plan 9. It s just so good. So many ideas from Plan 9 are just so prescient, and everything just feels right. Not just right like, feels good like, correct. The bit that I ve always liked the most is 9p, the network protocol for serving a filesystem over a network. This leads to all sorts of fun programs, like the Plan 9 ftp client being a 9p server you mount the ftp server and access files like any other files. It s kinda like if fuse were more fully a part of how the operating system worked, but fuse is all running client-side. With 9p there s a single client, and different servers that you can connect to, which may be backed by a hard drive, remote resources over something like SFTP, FTP, HTTP or even purely synthetic. The interesting (maybe sad?) part here is that 9p wound up outliving Plan 9 in terms of adoption 9p is in all sorts of places folks don t usually expect. For instance, the Windows Subsystem for Linux uses the 9p protocol to share files between Windows and Linux. ChromeOS uses it to share files with Crostini, and qemu uses 9p (virtio-p9) to share files between guest and host. If you re noticing a pattern here, you d be right; for some reason 9p is the go-to protocol to exchange files between hypervisor and guest. Why? I have no idea, except maybe due to being designed well, simple to implement, and it s a lot easier to validate the data being shared and validate security boundaries. Simplicity has its value. As a result, there s a lot of lingering 9p support kicking around. Turns out Linux can even handle mounting 9p filesystems out of the box. This means that I can deploy a filesystem to my LAN or my localhost by running a process on top of a computer that needs nothing special, and mount it over the network on an unmodified machine unlike fuse, where you d need client-specific software to run in order to mount the directory. For instance, let s mount a 9p filesystem running on my localhost machine, serving requests on 127.0.0.1:564 (tcp) that goes by the name mountpointname to /mnt.

$ mount -t 9p \
-o trans=tcp,port=564,version=9p2000.u,aname=mountpointname \
127.0.0.1 \
/mnt

Linux will mount away, and attach to the filesystem as the root user, and by default, attach to that mountpoint again for each local user that attempts to use it. Nifty, right? I think so. The server is able to keep track of per-user access and authorization along with the host OS.

WHEREIN I STYX WITH IT Since I wanted to push myself a bit more with rust and tokio specifically, I opted to implement the whole stack myself, without third party libraries on the critical path where I could avoid it. The 9p protocol (sometimes called Styx, the original name for it) is incredibly simple. It s a series of client to server requests, which receive a server to client response. These are, respectively, T messages, which transmit a request to the server, which trigger an R message in response (Reply messages). These messages are TLV payload with a very straight forward structure so straight forward, in fact, that I was able to implement a working server off nothing more than a handful of man pages. Later on after the basics worked, I found a more complete spec page that contains more information about the unix specific variant that I opted to use (9P2000.u rather than 9P2000) due to the level of Linux specific support for the 9P2000.u variant over the 9P2000 protocol.

MR ROBOTO The backend stack over at zoo is rust and tokio running i/o for an HTTP and WebRTC server. I figured I d pick something fairly similar to write my filesystem with, since 9P can be implemented on basically anything with I/O. That means tokio tcp server bits, which construct and use a 9p server, which has an idiomatic Rusty API that partially abstracts the raw R and T messages, but not so much as to cause issues with hiding implementation possibilities. At each abstraction level, there s an escape hatch allowing someone to implement any of the layers if required. I called this framework arigato which can be found over on docs.rs and crates.io.

/// Simplified version of the arigato File trait; this isn't actually
/// the same trait; there's some small cosmetic differences. The
/// actual trait can be found at:
///
/// https://docs.rs/arigato/latest/arigato/server/trait.File.html
trait File  
/// OpenFile is the type returned by this File via an Open call.
 type OpenFile: OpenFile;
/// Return the 9p Qid for this file. A file is the same if the Qid is
 /// the same. A Qid contains information about the mode of the file,
 /// version of the file, and a unique 64 bit identifier.
 fn qid(&self) -> Qid;
/// Construct the 9p Stat struct with metadata about a file.
 async fn stat(&self) -> FileResult<Stat>;
/// Attempt to update the file metadata.
 async fn wstat(&mut self, s: &Stat) -> FileResult<()>;
/// Traverse the filesystem tree.
 async fn walk(&self, path: &[&str]) -> FileResult<(Option<Self>, Vec<Self>)>;
/// Request that a file's reference be removed from the file tree.
 async fn unlink(&mut self) -> FileResult<()>;
/// Create a file at a specific location in the file tree.
 async fn create(
&mut self,
name: &str,
perm: u16,
ty: FileType,
mode: OpenMode,
extension: &str,
) -> FileResult<Self>;
/// Open the File, returning a handle to the open file, which handles
 /// file i/o. This is split into a second type since it is genuinely
 /// unrelated -- and the fact that a file is Open or Closed can be
 /// handled by the  arigato  server for us.
 async fn open(&mut self, mode: OpenMode) -> FileResult<Self::OpenFile>;
 
/// Simplified version of the arigato OpenFile trait; this isn't actually
/// the same trait; there's some small cosmetic differences. The
/// actual trait can be found at:
///
/// https://docs.rs/arigato/latest/arigato/server/trait.OpenFile.html
trait OpenFile  
/// iounit to report for this file. The iounit reported is used for Read
 /// or Write operations to signal, if non-zero, the maximum size that is
 /// guaranteed to be transferred atomically.
 fn iounit(&self) -> u32;
/// Read some number of bytes up to  buf.len()  from the provided
 ///  offset  of the underlying file. The number of bytes read is
 /// returned.
 async fn read_at(
&mut self,
buf: &mut [u8],
offset: u64,
) -> FileResult<u32>;
/// Write some number of bytes up to  buf.len()  from the provided
 ///  offset  of the underlying file. The number of bytes written
 /// is returned.
 fn write_at(
&mut self,
buf: &mut [u8],
offset: u64,
) -> FileResult<u32>;
 

Thanks, decade ago paultag! Let s do it! Let s use arigato to implement a 9p filesystem we ll call debugfs that will serve all the debug files shipped according to the Packages metadata from the apt archive. We ll fetch the Packages file and construct a filesystem based on the reported Build-Id entries. For those who don t know much about how an apt repo works, here s the 2-second crash course on what we re doing. The first is to fetch the Packages file, which is specific to a binary architecture (such as amd64, arm64 or riscv64). That architecture is specific to a component (such as main, contrib or non-free). That component is specific to a suite, such as stable, unstable or any of its aliases (bullseye, bookworm, etc). Let s take a look at the Packages.xz file for the unstable-debug suite, main component, for all amd64 binaries.

$ curl \
https://deb.debian.org/debian-debug/dists/unstable-debug/main/binary-amd64/Packages.xz \
  unxz

This will return the Debian-style rfc2822-like headers, which is an export of the metadata contained inside each .deb file which apt (or other tools that can use the apt repo format) use to fetch information about debs. Let s take a look at the debug headers for the netlabel-tools package in unstable which is a package named netlabel-tools-dbgsym in unstable-debug.

Package: netlabel-tools-dbgsym
Source: netlabel-tools (0.30.0-1)
Version: 0.30.0-1+b1
Installed-Size: 79
Maintainer: Paul Tagliamonte <paultag@debian.org>
Architecture: amd64
Depends: netlabel-tools (= 0.30.0-1+b1)
Description: debug symbols for netlabel-tools
Auto-Built-Package: debug-symbols
Build-Ids: e59f81f6573dadd5d95a6e4474d9388ab2777e2a
Description-md5: a0e587a0cf730c88a4010f78562e6db7
Section: debug
Priority: optional
Filename: pool/main/n/netlabel-tools/netlabel-tools-dbgsym_0.30.0-1+b1_amd64.deb
Size: 62776
SHA256: 0e9bdb087617f0350995a84fb9aa84541bc4df45c6cd717f2157aa83711d0c60

So here, we can parse the package headers in the Packages.xz file, and store, for each Build-Id, the Filename where we can fetch the .deb at. Each .deb contains a number of files but we re only really interested in the files inside the .deb located at or under /usr/lib/debug/.build-id/, which you can find in debugfs under rfc822.rs. It s crude, and very single-purpose, but I m feeling a bit lazy.

Who needs dpkg?! For folks who haven t seen it yet, a .deb file is a special type of .ar file, that contains (usually) three files inside debian-binary, control.tar.xz and data.tar.xz. The core of an .ar file is a fixed size (60 byte) entry header, followed by the specified size number of bytes.

[8 byte .ar file magic]
[60 byte entry header]
[N bytes of data]
[60 byte entry header]
[N bytes of data]
[60 byte entry header]
[N bytes of data]
...

First up was to implement a basic ar parser in ar.rs. Before we get into using it to parse a deb, as a quick diversion, let s break apart a .deb file by hand something that is a bit of a rite of passage (or at least it used to be? I m getting old) during the Debian nm (new member) process, to take a look at where exactly the .debug file lives inside the .deb file.

$ ar x netlabel-tools-dbgsym_0.30.0-1+b1_amd64.deb
$ ls
control.tar.xz debian-binary
data.tar.xz netlabel-tools-dbgsym_0.30.0-1+b1_amd64.deb
$ tar --list -f data.tar.xz   grep '.debug$'
./usr/lib/debug/.build-id/e5/9f81f6573dadd5d95a6e4474d9388ab2777e2a.debug

Since we know quite a bit about the structure of a .deb file, and I had to implement support from scratch anyway, I opted to implement a (very!) basic debfile parser using HTTP Range requests. HTTP Range requests, if supported by the server (denoted by a accept-ranges: bytes HTTP header in response to an HTTP HEAD request to that file) means that we can add a header such as range: bytes=8-68 to specifically request that the returned GET body be the byte range provided (in the above case, the bytes starting from byte offset 8 until byte offset 68). This means we can fetch just the ar file entry from the .deb file until we get to the file inside the .deb we are interested in (in our case, the data.tar.xz file) at which point we can request the body of that file with a final range request. I wound up writing a struct to handle a read_at-style API surface in hrange.rs, which we can pair with ar.rs above and start to find our data in the .deb remotely without downloading and unpacking the .deb at all. After we have the body of the data.tar.xz coming back through the HTTP response, we get to pipe it through an xz decompressor (this kinda sucked in Rust, since a tokio AsyncRead is not the same as an http Body response is not the same as std::io::Read, is not the same as an async (or sync) Iterator is not the same as what the xz2 crate expects; leading me to read blocks of data to a buffer and stuff them through the decoder by looping over the buffer for each lzma2 packet in a loop), and tarfile parser (similarly troublesome). From there we get to iterate over all entries in the tarfile, stopping when we reach our file of interest. Since we can t seek, but gdb needs to, we ll pull it out of the stream into a Cursor<Vec<u8>> in-memory and pass a handle to it back to the user. From here on out its a matter of gluing together a File traited struct in debugfs, and serving the filesystem over TCP using arigato. Done deal!

A quick diversion about compression I was originally hoping to avoid transferring the whole tar file over the network (and therefore also reading the whole debug file into ram, which objectively sucks), but quickly hit issues with figuring out a way around seeking around an xz file. What s interesting is xz has a great primitive to solve this specific problem (specifically, use a block size that allows you to seek to the block as close to your desired seek position just before it, only discarding at most block size - 1 bytes), but data.tar.xz files generated by dpkg appear to have a single mega-huge block for the whole file. I don t know why I would have expected any different, in retrospect. That means that this now devolves into the base case of How do I seek around an lzma2 compressed data stream ; which is a lot more complex of a question. Thankfully, notoriously brilliant tianon was nice enough to introduce me to Jon Johnson who did something super similar adapted a technique to seek inside a compressed gzip file, which lets his service oci.dag.dev seek through Docker container images super fast based on some prior work such as soci-snapshotter, gztool, and zran.c. He also pulled this party trick off for apk based distros over at apk.dag.dev, which seems apropos. Jon was nice enough to publish a lot of his work on this specifically in a central place under the name targz on his GitHub, which has been a ton of fun to read through. The gist is that, by dumping the decompressor s state (window of previous bytes, in-memory data derived from the last N-1 bytes) at specific checkpoints along with the compressed data stream offset in bytes and decompressed offset in bytes, one can seek to that checkpoint in the compressed stream and pick up where you left off creating a similar block mechanism against the wishes of gzip. It means you d need to do an O(n) run over the file, but every request after that will be sped up according to the number of checkpoints you ve taken. Given the complexity of xz and lzma2, I don t think this is possible for me at the moment especially given most of the files I ll be requesting will not be loaded from again especially when I can just cache the debug header by Build-Id. I want to implement this (because I m generally curious and Jon has a way of getting someone excited about compression schemes, which is not a sentence I thought I d ever say out loud), but for now I m going to move on without this optimization. Such a shame, since it kills a lot of the work that went into seeking around the .deb file in the first place, given the debian-binary and control.tar.gz members are so small.

The Good First, the good news right? It works! That s pretty cool. I m positive my younger self would be amused and happy to see this working; as is current day paultag. Let s take debugfs out for a spin! First, we need to mount the filesystem. It even works on an entirely unmodified, stock Debian box on my LAN, which is huge. Let s take it for a spin:

$ mount \
-t 9p \
-o trans=tcp,version=9p2000.u,aname=unstable-debug \
192.168.0.2 \
/usr/lib/debug/.build-id/

And, let s prove to ourselves that this actually mounted before we go trying to use it:

$ mount   grep build-id
192.168.0.2 on /usr/lib/debug/.build-id type 9p (rw,relatime,aname=unstable-debug,access=user,trans=tcp,version=9p2000.u,port=564)

Slick. We ve got an open connection to the server, where our host will keep a connection alive as root, attached to the filesystem provided in aname. Let s take a look at it.

$ ls /usr/lib/debug/.build-id/
00 0d 1a 27 34 41 4e 5b 68 75 82 8E 9b a8 b5 c2 CE db e7 f3
01 0e 1b 28 35 42 4f 5c 69 76 83 8f 9c a9 b6 c3 cf dc E7 f4
02 0f 1c 29 36 43 50 5d 6a 77 84 90 9d aa b7 c4 d0 dd e8 f5
03 10 1d 2a 37 44 51 5e 6b 78 85 91 9e ab b8 c5 d1 de e9 f6
04 11 1e 2b 38 45 52 5f 6c 79 86 92 9f ac b9 c6 d2 df ea f7
05 12 1f 2c 39 46 53 60 6d 7a 87 93 a0 ad ba c7 d3 e0 eb f8
06 13 20 2d 3a 47 54 61 6e 7b 88 94 a1 ae bb c8 d4 e1 ec f9
07 14 21 2e 3b 48 55 62 6f 7c 89 95 a2 af bc c9 d5 e2 ed fa
08 15 22 2f 3c 49 56 63 70 7d 8a 96 a3 b0 bd ca d6 e3 ee fb
09 16 23 30 3d 4a 57 64 71 7e 8b 97 a4 b1 be cb d7 e4 ef fc
0a 17 24 31 3e 4b 58 65 72 7f 8c 98 a5 b2 bf cc d8 E4 f0 fd
0b 18 25 32 3f 4c 59 66 73 80 8d 99 a6 b3 c0 cd d9 e5 f1 fe
0c 19 26 33 40 4d 5a 67 74 81 8e 9a a7 b4 c1 ce da e6 f2 ff

Outstanding. Let s try using gdb to debug a binary that was provided by the Debian archive, and see if it ll load the ELF by build-id from the right .deb in the unstable-debug suite:

$ gdb -q /usr/sbin/netlabelctl
Reading symbols from /usr/sbin/netlabelctl...
Reading symbols from /usr/lib/debug/.build-id/e5/9f81f6573dadd5d95a6e4474d9388ab2777e2a.debug...
(gdb)

Yes! Yes it will!

$ file /usr/lib/debug/.build-id/e5/9f81f6573dadd5d95a6e4474d9388ab2777e2a.debug
/usr/lib/debug/.build-id/e5/9f81f6573dadd5d95a6e4474d9388ab2777e2a.debug: ELF 64-bit LSB shared object, x86-64, version 1 (SYSV), dynamically linked, interpreter *empty*, BuildID[sha1]=e59f81f6573dadd5d95a6e4474d9388ab2777e2a, for GNU/Linux 3.2.0, with debug_info, not stripped

The Bad Linux s support for 9p is mainline, which is great, but it s not robust. Network issues or server restarts will wedge the mountpoint (Linux can t reconnect when the tcp connection breaks), and things that work fine on local filesystems get translated in a way that causes a lot of network chatter for instance, just due to the way the syscalls are translated, doing an ls, will result in a stat call for each file in the directory, even though linux had just got a stat entry for every file while it was resolving directory names. On top of that, Linux will serialize all I/O with the server, so there s no concurrent requests for file information, writes, or reads pending at the same time to the server; and read and write throughput will degrade as latency increases due to increasing round-trip time, even though there are offsets included in the read and write calls. It works well enough, but is frustrating to run up against, since there s not a lot you can do server-side to help with this beyond implementing the 9P2000.L variant (which, maybe is worth it).

The Ugly Unfortunately, we don t know the file size(s) until we ve actually opened the underlying tar file and found the correct member, so for most files, we don t know the real size to report when getting a stat. We can t parse the tarfiles for every stat call, since that d make ls even slower (bummer). Only hiccup is that when I report a filesize of zero, gdb throws a bit of a fit; let s try with a size of 0 to start:

$ ls -lah /usr/lib/debug/.build-id/e5/9f81f6573dadd5d95a6e4474d9388ab2777e2a.debug
-r--r--r-- 1 root root 0 Dec 31 1969 /usr/lib/debug/.build-id/e5/9f81f6573dadd5d95a6e4474d9388ab2777e2a.debug
$ gdb -q /usr/sbin/netlabelctl
Reading symbols from /usr/sbin/netlabelctl...
Reading symbols from /usr/lib/debug/.build-id/e5/9f81f6573dadd5d95a6e4474d9388ab2777e2a.debug...
warning: Discarding section .note.gnu.build-id which has a section size (24) larger than the file size [in module /usr/lib/debug/.build-id/e5/9f81f6573dadd5d95a6e4474d9388ab2777e2a.debug]
[...]

This obviously won t work since gdb will throw away all our hard work because of stat s output, and neither will loading the real size of the underlying file. That only leaves us with hardcoding a file size and hope nothing else breaks significantly as a result. Let s try it again:

$ ls -lah /usr/lib/debug/.build-id/e5/9f81f6573dadd5d95a6e4474d9388ab2777e2a.debug
-r--r--r-- 1 root root 954M Dec 31 1969 /usr/lib/debug/.build-id/e5/9f81f6573dadd5d95a6e4474d9388ab2777e2a.debug
$ gdb -q /usr/sbin/netlabelctl
Reading symbols from /usr/sbin/netlabelctl...
Reading symbols from /usr/lib/debug/.build-id/e5/9f81f6573dadd5d95a6e4474d9388ab2777e2a.debug...
(gdb)

Much better. I mean, terrible but better. Better for now, anyway.

Kilroy was here Do I think this is a particularly good idea? I mean; kinda. I m probably going to make some fun 9p arigato-based filesystems for use around my LAN, but I don t think I ll be moving to use debugfs until I can figure out how to ensure the connection is more resilient to changing networks, server restarts and fixes on i/o performance. I think it was a useful exercise and is a pretty great hack, but I don t think this ll be shipping anywhere anytime soon. Along with me publishing this post, I ve pushed up all my repos; so you should be able to play along at home! There s a lot more work to be done on arigato; but it does handshake and successfully export a working 9P2000.u filesystem. Check it out on on my github at arigato, debugfs and also on crates.io and docs.rs. At least I can say I was here and I got it working after all these years.

• [1] https://en.wikipedia.org/wiki/Digital_Markets_Act
• [2] https://tinyurl.com/28a5mg7c
• [3] https://en.wikipedia.org/wiki/The_Tactful_Saboteur