feat: add evil bit support

gnome-extensions/evil-bit-toggle/extension.js

@@ -0,0 +1,151 @@
+import Gio from 'gi://Gio';
+import GLib from 'gi://GLib';
+import GObject from 'gi://GObject';
+
+import {Extension} from 'resource:///org/gnome/shell/extensions/extension.js';
+import * as Main from 'resource:///org/gnome/shell/ui/main.js';
+import * as QuickSettings from 'resource:///org/gnome/shell/ui/quickSettings.js';
+
+const EVIL_BIT_CTL = '@evilBitCtl@';
+const PKEXEC = '/run/wrappers/bin/pkexec';
+const STATE_FILE = '/run/evil-bit-toggle/enabled';
+const ICON_NAME = 'dialog-warning-symbolic';
+
+const EvilBitToggle = GObject.registerClass(
+class EvilBitToggle extends QuickSettings.QuickToggle {
+    constructor() {
+        super({
+            title: 'Evil Bit',
+            subtitle: 'RFC 3514: good',
+            iconName: ICON_NAME,
+            toggleMode: true,
+        });
+
+        this._syncing = false;
+        this._pending = false;
+        this._destroyed = false;
+        this._syncFromState();
+
+        this._checkedId = this.connect('notify::checked', () => {
+            if (this._syncing)
+                return;
+
+            this._setEvilBit(this.checked);
+        });
+    }
+
+    _isEnabled() {
+        return GLib.file_test(STATE_FILE, GLib.FileTest.EXISTS);
+    }
+
+    _syncFromState() {
+        this._syncing = true;
+        this.checked = this._isEnabled();
+        this._syncing = false;
+        this._syncSubtitle();
+    }
+
+    _setEvilBit(enabled) {
+        if (this._pending)
+            return;
+
+        this._pending = true;
+        this.reactive = false;
+        this.subtitle = 'Applying...';
+
+        const action = enabled ? 'enable' : 'disable';
+        let proc;
+
+        try {
+            proc = Gio.Subprocess.new(
+                [PKEXEC, EVIL_BIT_CTL, action],
+                Gio.SubprocessFlags.STDOUT_PIPE | Gio.SubprocessFlags.STDERR_PIPE
+            );
+        } catch (error) {
+            this._finishSetEvilBit(error);
+            return;
+        }
+
+        proc.communicate_utf8_async(null, null, (subprocess, result) => {
+            try {
+                const [, , stderr] = subprocess.communicate_utf8_finish(result);
+
+                if (!subprocess.get_successful())
+                    throw new Error(stderr.trim() || `evil-bitctl ${action} failed`);
+
+                this._finishSetEvilBit(null);
+            } catch (error) {
+                this._finishSetEvilBit(error);
+            }
+        });
+    }
+
+    _finishSetEvilBit(error) {
+        if (error)
+            console.warn(`Unable to toggle Evil Bit: ${error.message}`);
+
+        if (this._destroyed)
+            return;
+
+        this._pending = false;
+        this.reactive = true;
+        this._syncFromState();
+    }
+
+    _syncSubtitle() {
+        this.subtitle = this.checked ? 'RFC 3514: evil' : 'RFC 3514: good';
+    }
+
+    destroy() {
+        this._destroyed = true;
+
+        if (this._checkedId) {
+            this.disconnect(this._checkedId);
+            this._checkedId = null;
+        }
+
+        super.destroy();
+    }
+});
+
+const EvilBitIndicator = GObject.registerClass(
+class EvilBitIndicator extends QuickSettings.SystemIndicator {
+    constructor() {
+        super();
+
+        this._indicator = this._addIndicator();
+        this._indicator.icon_name = ICON_NAME;
+
+        this._toggle = new EvilBitToggle();
+        this._indicator.visible = this._toggle.checked;
+        this._checkedId = this._toggle.connect('notify::checked', () => {
+            this._indicator.visible = this._toggle.checked;
+        });
+
+        this.quickSettingsItems.push(this._toggle);
+    }
+
+    destroy() {
+        if (this._checkedId) {
+            this._toggle.disconnect(this._checkedId);
+            this._checkedId = null;
+        }
+
+        this.quickSettingsItems.forEach(item => item.destroy());
+        this._toggle = null;
+
+        super.destroy();
+    }
+});
+
+export default class EvilBitToggleExtension extends Extension {
+    enable() {
+        this._indicator = new EvilBitIndicator();
+        Main.panel.statusArea.quickSettings.addExternalIndicator(this._indicator);
+    }
+
+    disable() {
+        this._indicator.destroy();
+        this._indicator = null;
+    }
+}

gnome-extensions/evil-bit-toggle/metadata.json

@@ -0,0 +1,6 @@
+{
+  "uuid": "evil-bit-toggle@jetpham.github.com",
+  "name": "Evil Bit Toggle",
+  "description": "Adds a Quick Settings toggle for the RFC 3514 evil bit.",
+  "shell-version": ["49"]
+}

home-modules/desktop.nix

@@ -182,6 +182,7 @@ in
         "appindicatorsupport@rgcjonas.gmail.com"
         "gnome-shell-extension-maximized-by-default@stiggimy.github.com"
         "no-titlebar-when-maximized@alec.ninja"
+        "evil-bit-toggle@jetpham.github.com"
         "reduced-motion-toggle@jetpham.github.com"
       ];
       favorite-apps = favoriteApps;

home-modules/packages.nix

@@ -6,6 +6,68 @@
 }:
 
 let
+  evilBitCtl = pkgs.writeShellApplication {
+    name = "evil-bitctl";
+    runtimeInputs = [
+      pkgs.coreutils
+      pkgs.nftables
+    ];
+    text = ''
+      state_dir=/run/evil-bit-toggle
+      state_file="$state_dir/enabled"
+      table=evil_bit
+      chain=output
+
+      usage() {
+        printf 'Usage: evil-bitctl {enable|disable|status}\n' >&2
+        exit 64
+      }
+
+      enable() {
+        nft add table ip "$table" 2>/dev/null || true
+
+        if nft list chain ip "$table" "$chain" >/dev/null 2>&1; then
+          nft flush chain ip "$table" "$chain"
+        else
+          nft add chain ip "$table" "$chain" '{ type route hook output priority mangle; policy accept; }'
+        fi
+
+        nft add rule ip "$table" "$chain" ip frag-off set ip frag-off '|' 0x8000
+        install -d -m 0755 "$state_dir"
+        touch "$state_file"
+      }
+
+      disable() {
+        nft delete table ip "$table" 2>/dev/null || true
+        rm -f "$state_file"
+        rmdir "$state_dir" 2>/dev/null || true
+      }
+
+      status() {
+        if [ -e "$state_file" ] && nft list table ip "$table" >/dev/null 2>&1; then
+          printf 'enabled\n'
+        else
+          printf 'disabled\n'
+        fi
+      }
+
+      case "''${1:-}" in
+        enable)
+          enable
+          ;;
+        disable)
+          disable
+          ;;
+        status)
+          status
+          ;;
+        *)
+          usage
+          ;;
+      esac
+    '';
+  };
+
   reducedMotionToggleExtension = pkgs.stdenvNoCC.mkDerivation {
     pname = "gnome-shell-extension-reduced-motion-toggle";
     version = "1";
@@ -20,6 +82,24 @@ let
       runHook postInstall
     '';
   };
+
+  evilBitToggleExtension = pkgs.stdenvNoCC.mkDerivation {
+    pname = "gnome-shell-extension-evil-bit-toggle";
+    version = "1";
+    src = ../gnome-extensions/evil-bit-toggle;
+
+    installPhase = ''
+      runHook preInstall
+
+      substituteInPlace extension.js \
+        --replace-fail @evilBitCtl@ ${evilBitCtl}/bin/evil-bitctl
+
+      mkdir -p "$out/share/gnome-shell/extensions/evil-bit-toggle@jetpham.github.com"
+      cp -r . "$out/share/gnome-shell/extensions/evil-bit-toggle@jetpham.github.com"
+
+      runHook postInstall
+    '';
+  };
 in
 
 {
@@ -105,6 +185,7 @@ in
     gnomeExtensions.system-monitor-next
     gnomeExtensions.tailscale-qs
     gnomeExtensions.wifi-qrcode
+    evilBitToggleExtension
     reducedMotionToggleExtension
 
     nerd-fonts.commit-mono