testsAndMisc/linux_configuration/.github/copilot-instructions.md

AI agent quickstart for this repo

This repo automates Linux desktop bootstrap, hardening, and i3 setup. It’s primarily Bash scripts with idempotent installers, systemd units, and policy guardrails. Use these notes to work effectively with the codebase.

Big picture

• fresh-install/: end-to-end bootstrap for Arch/Ubuntu workstations. Reads package lists, configures pacman/makepkg, sets up GPU drivers, i3, hosts guard, pacman wrapper, and useful services. Example: fresh-install/main.sh orchestrates most steps and sources detect_gpu*.sh.
• hosts/: manages a highly-opinionated /etc/hosts via StevenBlack upstream with custom edits, plus “guard” friction:
  • hosts/install.sh builds and locks /etc/hosts (immutable/append-only; selective unblocks; custom blocks).
  • hosts/guard/ enforcement is provided by guard-lib (guardctl, installed outside this repo): a file-guard instance per target (hosts, nsswitch, resolved) with a path-watcher, optional RO bind mount, generic pacman hooks, and per-target plugins under hosts/guard/plugins/. The pre-guard-lib scripts (setup_hosts_guard.sh, enforce-*.sh, per-target systemd units, psychological/unlock-hosts.sh) are archived at github.com/kuhyx/testsAndMisc-archive — see ./fixes/migrate_hosts_guard_to_guard_lib.sh for how the migration works.
• periodic_background/digital_wellbeing/pacman/: a policy-aware pacman wrapper with friction mechanics.
  • pacman_wrapper.sh intercepts transactions, runs hosts-guard pre/post hooks, handles stale db lock, auto-wires maintenance services, adds a weekend-only “Steam” challenge powered by words.txt, and removes VirtualBox VMs after each transaction. It has no package block/allow lists (retired 2026-10-17; hosts/DNS blocking covers that).
  • install_pacman_wrapper.sh backs up /usr/bin/pacman to pacman.orig and symlinks to the wrapper.
• periodic_background/system-maintenance/: templates and installer for periodic jobs and monitoring.
  • setup_periodic_system.sh installs: /usr/local/bin/periodic-system-maintenance.sh, a timer (periodic-system-maintenance.timer), a startup oneshot, and hosts-file-monitor.service that restores /etc/hosts if tampered. Also installs a browser pre-exec wrapper that re-runs the hosts installer before launching common browsers.
• i3/ + i3blocks/: install i3 and i3blocks configs with small font sizing logic (i3/install.sh).

Conventions you should follow

• Bash style: use set -e or set -euo pipefail, re-exec with sudo if not root, be idempotent, and log to /var/log/* with timestamps. Examples: setup_periodic_system.sh, ./fixes/migrate_hosts_guard_to_guard_lib.sh.
• Install via templates: scripts under periodic_background/system-maintenance/bin and .../systemd are templates. The setup script substitutes placeholders like __HOSTS_INSTALL_SCRIPT__ and __PACMAN_WRAPPER_INSTALL__ before installing to /usr/local/bin and /etc/systemd/system. Don’t edit installed copies directly; modify templates and the setup script.
• Package lists: fresh-install/pacman_packages.txt and aur_packages.txt treat any line not starting with lowercase alnum as a comment.

Core workflows (what to run)

• Fresh machine: run from repo root
  • fresh-install/main.sh (bootstraps configs, GPU, hosts, i3, pacman wrapper, services). It assumes the repo is at ~/src/testsAndMisc/linux_configuration in some steps.
• Periodic services: sudo periodic_background/setup_periodic_system.sh (installs timer, startup service, hosts monitor, and browser pre-exec wrapper; then performs an initial run).
• Pacman wrapper only: sudo periodic_background/digital_wellbeing/pacman/install_pacman_wrapper.sh (backs up pacman and wires the wrapper). The wrapper auto-runs hosts-guard pre/post hooks and can self-setup periodic services when missing.
• Hosts guard:
  • sudo hosts/install.sh to (re)build /etc/hosts from cache/upstream then lock it.
  • Guard layers (hosts/nsswitch/resolved) are managed by guardctl file-guard <install|status|unlock|uninstall> <name>; see ./fixes/migrate_hosts_guard_to_guard_lib.sh to (re)install them.
  • To edit a guarded file: sudo guardctl file-guard unlock <name>, edit, then let the path-watcher re-lock it (or guardctl file-guard enforce <name>).
• i3 config: i3/install.sh (copies i3 and i3blocks, adjusts font size; installs required tools conditionally for Arch/Ubuntu).

Integration points and gotchas

• Pacman interception: pacman_wrapper.sh sets PACMAN_BIN=/usr/bin/pacman.orig and symlinks /usr/bin/pacman -> wrapper. Keep this invariant when changing the wrapper.
• Hosts hooks: pacman transactions are unlocked/relocked by guard-lib's generic hooks (/etc/pacman.d/hooks/10-guard-lib-unlock-all.hook, 90-guard-lib-relock-all.hook), which iterate every registered file-guard instance rather than being hosts-specific.
• Logs: check /var/log/periodic-system-maintenance.log and /var/log/hosts-file-monitor.log for service behavior; timer and services live under periodic_background/system-maintenance/systemd/ (templates).
• Browser pre-exec: setup creates /usr/local/bin/browser-preexec-wrapper and symlinks common browser names to it; it silently re-runs the hosts installer before launching the real binary in /usr/bin.

Patterns to reuse when adding features

• Follow the sudo re-exec + idempotent install pattern from setup_periodic_system.sh and ./fixes/migrate_hosts_guard_to_guard_lib.sh.
• Add new periodic behaviors as templates under periodic_background/system-maintenance/bin and .../systemd, then extend setup_periodic_system.sh to install/enable them.
• Add package friction by adding check_for_<pkg> + prompt_for_<pkg>_challenge blocks in the wrapper (now in github.com/kuhyx/digital-wellbeing).
• Run meta/shell_check.sh to detect things to fix before committing.

Detailed LLM Documentation

For in-depth understanding of specific components, see these dedicated guides:

• Hosts Guard: ./fixes/migrate_hosts_guard_to_guard_lib.sh header comment - guard-lib migration, protection layers, canonical copies, path watchers. The pre-guard-lib README is archived at github.com/kuhyx/testsAndMisc-archive.
• Pacman Wrapper: periodic_background/digital_wellbeing/pacman/DOCS-pacman-wrapper-reference.md - Policy files, integrity checks, challenges
• Midnight Shutdown: periodic_background/digital_wellbeing/DOCS-midnight-shutdown-reference.md - Schedule protection, timer system
• Compulsive Block: periodic_background/digital_wellbeing/DOCS-compulsive-block-reference.md - App launch limiting
• Security Analysis: docs/DOCS-security-hardening-analysis.md - Vulnerabilities and implementation roadmap

Digital Wellbeing Components Summary

Component	Purpose	Key Files
Hosts Guard	Block websites via /etc/hosts	hosts/install.sh, guardctl (guard-lib), hosts/guard/plugins/*
Pacman Wrapper	Block package installation	periodic_background/digital_wellbeing/pacman/*
Midnight Shutdown	Auto-shutdown at night	periodic_background/digital_wellbeing/setup_midnight_shutdown.sh
Compulsive Block	Limit app launches	periodic_background/digital_wellbeing/block_compulsive_opening.sh
Music Wrapper	Block music during focus	periodic_background/digital_wellbeing/youtube-music-wrapper.sh
Screen Locker	Require workout to unlock	External: ~/src/testsAndMisc/python_pkg/screen_locker/