nixos/lasuite-docs: add systemd service to create postgresql unaccent

function

It is unsafe for a non-superadmin user to create a C functin
in postgresql, so we need to create the function via the
superadmin postgres user. This function (immutable unaccent) is
needed by lasuite-docs since 4.2.0 and is used to search for keys
without accents.

https://github.com/suitenumerique/docs/releases/tag/v4.2.0
https://github.com/suitenumerique/docs/compare/v4.1.0...v4.2.0

nixos/modules/services/web-apps/lasuite-docs.nix

@@ -346,6 +346,56 @@ in
   };
 
   config = mkIf cfg.enable {
+    systemd.services.lasuite-docs-postgresql-setup = mkIf cfg.postgresql.createLocally {
+      wantedBy = [ "lasuite-docs.target" ];
+      requiredBy = [ "lasuite-docs.service" ];
+      before = [ "lasuite-docs.service" ];
+      after = [ "postgresql-setup.service" ];
+
+      serviceConfig = {
+        Slice = "system-lasuite-docs.slice";
+        Type = "oneshot";
+        User = "postgres";
+
+        # lasuite-docs user cannot create a C function as it is unsafe.
+        ExecStart = ''
+          ${lib.getExe' config.services.postgresql.package "psql"} --port=${toString config.services.postgresql.settings.port} -d lasuite-docs -c "CREATE OR REPLACE FUNCTION public.immutable_unaccent(regdictionary, text) RETURNS text LANGUAGE c IMMUTABLE PARALLEL SAFE STRICT AS '$libdir/unaccent', 'unaccent_dict';"
+        '';
+
+        # hardening
+        AmbientCapabilities = "";
+        CapabilityBoundingSet = [ "" ];
+        DevicePolicy = "closed";
+        LockPersonality = true;
+        NoNewPrivileges = true;
+        PrivateDevices = true;
+        PrivateTmp = true;
+        PrivateUsers = true;
+        ProcSubset = "pid";
+        ProtectClock = true;
+        ProtectControlGroups = true;
+        ProtectHome = true;
+        ProtectHostname = true;
+        ProtectKernelLogs = true;
+        ProtectKernelModules = true;
+        ProtectKernelTunables = true;
+        ProtectProc = "invisible";
+        ProtectSystem = "strict";
+        RemoveIPC = true;
+        RestrictAddressFamilies = [
+          "AF_INET"
+          "AF_INET6"
+          "AF_UNIX"
+        ];
+        RestrictNamespaces = true;
+        RestrictRealtime = true;
+        RestrictSUIDSGID = true;
+        SystemCallArchitectures = "native";
+        UMask = "0077";
+      };
+
+    };
+
     systemd.services.lasuite-docs = {
       description = "Docs from SuiteNumérique";
       after = [