Detect WSL1 and error

[cole-h]

WSL1 is not supported because some things Nix relies on to work are not available.

Description

Closes #281.

Checklist

• Formatted with cargo fmt
• Built with nix build
• Ran flake checks with nix flake check
• Added or updated relevant tests (leave unchecked if not applicable)
• Added or updated relevant documentation (leave unchecked if not applicable)
• Linked to related issues (leave unchecked if not applicable)

Validating with install.determinate.systems

If a maintainer has added the upload to s3 label to this PR, it will become available for installation via install.determinate.systems:

curl --proto '=https' --tlsv1.2 -sSf -L https://install.determinate.systems/nix/pr/$PR_NUMBER | sh -s -- install

[cole-h]

Nice.

[stuv]

Sorry to open up this merge. But I wanted to install Determinate Systems Nix on WSL1 and I didn't get the error like this.

The one I bumped into was:

Proceed? ([Y]es/[n]o/[e]xplain): y
 INFO Step: Create directory `/nix`
 INFO Step: Provision Nix
 INFO Step: Create build users (UID 30001-30032) and group (GID 30000)
 INFO Step: Configure Nix
ERROR
   0: Install failure
   1: Error executing action
   2: Action `configure_nix` errored
   3: Action `setup_default_profile` errored
   4: Failed to execute command with status 1 `HOME="/root" NIX_SSL_CERT_FILE="/nix/store/852a51xd3m7jyzifqimxc3jf3w2ipc4k-nss-cacert-3.101/etc/ssl/certs/ca-bundle.crt" "/nix/store/hdy82qidsybc3fg561pqfwagv44vschb-nix-2.24.10/bin/nix-env" "--option" "substitute" "false" "-i" "/nix/store/hdy82qidsybc3fg561pqfwagv44vschb-nix-2.24.10"`, stdout:
      stderr: installing 'nix-2.24.10'
      error:
             … while setting up the build environment

             error: unable to load seccomp BPF program: Invalid argument

   4:

Location:
   src/cli/subcommand/install.rs:256

This was all with the default settings for as far as I can remember. Using the standard install command from the website:
curl --proto '=https' --tlsv1.2 -sSf -L https://install.determinate.systems/nix | \ sh -s -- install

I assume nix still isn't supported on WSL1? It's unfortunate, but with this computer I can't update it to WSL2, so I am stuck with WSL1 and would like to see if in any way it's possible to have some nix on this machine to make life a bit more bareable.

[cole-h]

You are correct in that WSL1 is still not (explicitly) supported. If you can provide information on a more reliable way of detecting if the WSL version used is WSL1 and not WSL2, I'd be grateful!

In the meantime, while this "bug" exists, you can see if using --init none and one (or both) of --extra-conf "sandbox = false" and --extra-conf "filter-syscalls = false" works to install Nix -- if so, then we might be able to make WSL1 "usable" (by documenting this combination of flags).