nixos/evremap: init module

nixos/doc/manual/release-notes/rl-2411.section.md

@@ -208,6 +208,8 @@
 
 - [tiny-dfr](https://github.com/WhatAmISupposedToPutHere/tiny-dfr), a dynamic function row daemon for the Touch Bar found on some Apple laptops. Available as [hardware.apple.touchBar.enable](options.html#opt-hardware.apple.touchBar.enable).
 
+- [evremap](https://github.com/wez/evremap), a keyboard input remapper for Linux/Wayland systems. Available as [services.evremap](options.html#opt-services.evremap).
+
 ## Backward Incompatibilities {#sec-release-24.11-incompatibilities}
 
 - The `sound` options have been removed or renamed, as they had a lot of unintended side effects. See [below](#sec-release-24.11-migration-sound) for details.

nixos/modules/module-list.nix

@@ -752,6 +752,7 @@
   ./services/misc/etebase-server.nix
   ./services/misc/etesync-dav.nix
   ./services/misc/evdevremapkeys.nix
+  ./services/misc/evremap.nix
   ./services/misc/felix.nix
   ./services/misc/flaresolverr.nix
   ./services/misc/forgejo.nix

nixos/modules/services/misc/evremap.nix

@@ -0,0 +1,167 @@
+{
+  config,
+  lib,
+  pkgs,
+  ...
+}:
+let
+  cfg = config.services.evremap;
+  format = pkgs.formats.toml { };
+
+  key = lib.types.strMatching "KEY_[[:upper:]]+" // {
+    description = "key ID prefixed with KEY_";
+  };
+
+  mkKeyOption =
+    description:
+    lib.mkOption {
+      type = key;
+      description = ''
+        ${description}
+
+        You can get a list of keys by running `evremap list-keys`.
+      '';
+    };
+  mkKeySeqOption =
+    description:
+    (mkKeyOption description)
+    // {
+      type = lib.types.listOf key;
+    };
+
+  dualRoleModule = lib.types.submodule {
+    options = {
+      input = mkKeyOption "The key that should be remapped.";
+      hold = mkKeySeqOption "The key sequence that should be output when the input key is held.";
+      tap = mkKeySeqOption "The key sequence that should be output when the input key is tapped.";
+    };
+  };
+
+  remapModule = lib.types.submodule {
+    options = {
+      input = mkKeySeqOption "The key sequence that should be remapped.";
+      output = mkKeySeqOption "The key sequence that should be output when the input sequence is entered.";
+    };
+  };
+in
+{
+  options.services.evremap = {
+    enable = lib.mkEnableOption "evremap, a keyboard input remapper for Linux/Wayland systems";
+
+    settings = lib.mkOption {
+      type = lib.types.submodule {
+        freeformType = format.type;
+
+        options = {
+          device_name = lib.mkOption {
+            type = lib.types.str;
+            example = "AT Translated Set 2 keyboard";
+            description = ''
+              The name of the device that should be remapped.
+
+              You can get a list of devices by running `evremap list-devices` with elevated permissions.
+            '';
+          };
+
+          dual_role = lib.mkOption {
+            type = lib.types.listOf dualRoleModule;
+            default = [ ];
+            example = [
+              {
+                input = "KEY_CAPSLOCK";
+                hold = [ "KEY_LEFTCTRL" ];
+                tap = [ "KEY_ESC" ];
+              }
+            ];
+            description = ''
+              List of dual-role remappings that output different key sequences based on whether the
+              input key is held or tapped.
+            '';
+          };
+
+          remap = lib.mkOption {
+            type = lib.types.listOf remapModule;
+            default = [ ];
+            example = [
+              {
+                input = [
+                  "KEY_LEFTALT"
+                  "KEY_UP"
+                ];
+                output = [ "KEY_PAGEUP" ];
+              }
+            ];
+            description = ''
+              List of remappings.
+            '';
+          };
+        };
+      };
+
+      description = ''
+        Settings for evremap.
+
+        See the [upstream documentation](https://github.com/wez/evremap/blob/master/README.md#configuration)
+        for how to configure evremap.
+      '';
+      default = { };
+    };
+  };
+
+  config = lib.mkIf cfg.enable {
+    environment.systemPackages = [ pkgs.evremap ];
+
+    hardware.uinput.enable = lib.mkDefault true;
+
+    systemd.services.evremap = {
+      description = "evremap service";
+      wantedBy = [ "multi-user.target" ];
+
+      script = "${lib.getExe pkgs.evremap} remap ${format.generate "evremap.toml" cfg.settings}";
+
+      serviceConfig = {
+        DynamicUser = true;
+        User = "evremap";
+        SupplementaryGroups = [
+          config.users.groups.input.name
+          config.users.groups.uinput.name
+        ];
+        Restart = "on-failure";
+        RestartSec = 5;
+        TimeoutSec = 20;
+
+        # Hardening
+        ProtectClock = true;
+        ProtectKernelLogs = true;
+        ProtectControlGroups = true;
+        ProtectKernelModules = true;
+        ProtectHostname = true;
+        ProtectKernelTunables = true;
+        ProtectProc = "invisible";
+        ProtectHome = true;
+        ProcSubset = "pid";
+
+        PrivateTmp = true;
+        PrivateNetwork = true;
+        PrivateUsers = true;
+
+        RestrictRealtime = true;
+        RestrictNamespaces = true;
+        RestrictAddressFamilies = "none";
+
+        MemoryDenyWriteExecute = true;
+        LockPersonality = true;
+        IPAddressDeny = "any";
+        AmbientCapabilities = "";
+        CapabilityBoundingSet = "";
+        SystemCallArchitectures = "native";
+        SystemCallFilter = [
+          "@system-service"
+          "~@resources"
+          "~@privileged"
+        ];
+        UMask = "0027";
+      };
+    };
+  };
+}