From 9f4d207bb72f4808ef60560e70a811c321bebabe Mon Sep 17 00:00:00 2001
From: tv <tv@krebsco.de>
Date: Sun, 2 Dec 2018 15:35:37 +0100
Subject: [PATCH] tv slock service: init

---
 tv/3modules/default.nix |  1 +
 tv/3modules/slock.nix   | 71 +++++++++++++++++++++++++++++++++++++++++
 2 files changed, 72 insertions(+)
 create mode 100644 tv/3modules/slock.nix

diff --git a/tv/3modules/default.nix b/tv/3modules/default.nix
index 6172feb03..f53a58e9a 100644
--- a/tv/3modules/default.nix
+++ b/tv/3modules/default.nix
@@ -6,6 +6,7 @@
     ./hosts.nix
     ./iptables.nix
     ./nixpkgs-overlays.nix
+    ./slock.nix
     ./x0vncserver.nix
   ];
 }
diff --git a/tv/3modules/slock.nix b/tv/3modules/slock.nix
new file mode 100644
index 000000000..1c84b1e9e
--- /dev/null
+++ b/tv/3modules/slock.nix
@@ -0,0 +1,71 @@
+with import <stockholm/lib>;
+{ config, pkgs, ... }: let
+  cfg = config.tv.slock;
+in {
+  options.tv.slock = {
+    enable = mkEnableOption "tv.slock";
+    package = mkOption {
+      default = pkgs.execBin "slock" rec {
+        filename = "${pkgs.systemd}/bin/systemctl";
+        argv = [ filename "start" "slock-${cfg.user.name}.service" ];
+      };
+      type = types.package;
+    };
+    user = mkOption {
+      type = types.user;
+    };
+  };
+  config = mkIf cfg.enable {
+    security.polkit.extraConfig = /* js */ ''
+      polkit.addRule(function(action, subject) {
+        if (action.id == "org.freedesktop.systemd1.manage-units" &&
+            action.lookup("unit") == "slock-${cfg.user.name}.service" &&
+            subject.user == ${toJSON cfg.user.name}) {
+          return polkit.Result.YES;
+        }
+      });
+    '';
+    systemd.services."slock-${cfg.user.name}" = {
+      environment = {
+        DISPLAY = ":${toString config.services.xserver.display}";
+        LD_PRELOAD = pkgs.runCommandCC "slock-${cfg.user.name}.so" {
+          passAsFile = ["text"];
+          text = /* c */ ''
+            #include <shadow.h>
+            #include <unistd.h>
+
+            static struct spwd entry = {
+              .sp_namp = "",
+              .sp_pwdp =
+                ${toC config.users.users.${cfg.user.name}.hashedPassword},
+              .sp_lstchg = 0,
+              .sp_min = 0,
+              .sp_max = 0,
+              .sp_warn = 0,
+              .sp_inact = 0,
+              .sp_expire = 0,
+              .sp_flag = 0,
+            };
+
+            extern struct spwd *getspnam(const char *name) { return &entry; }
+            extern int setgroups(size_t size, const gid_t *list) { return 0; }
+            extern int setgid(gid_t gid) { return 0; }
+            extern int setuid(uid_t uid) { return 0; }
+          '';
+        } /* sh */ ''
+          gcc -Wall -shared -o $out -xc "$textPath"
+        '';
+      };
+      restartIfChanged = false;
+      serviceConfig = {
+        ExecStart = "${pkgs.slock}/bin/slock";
+        OOMScoreAdjust = -1000;
+        Restart = "on-failure";
+        RestartSec = "100ms";
+        StartLimitBurst = 0;
+        SyslogIdentifier = "slock";
+        User = cfg.user.name;
+      };
+    };
+  };
+}