{ config, lib, pkgs, ... }: with lib; let inherit (pkgs) cups; cfg = config.services.printing; additionalBackends = pkgs.runCommand "additional-cups-backends" { } '' mkdir -p $out if [ ! -e ${pkgs.cups}/lib/cups/backend/smb ]; then mkdir -p $out/lib/cups/backend ln -sv ${pkgs.samba}/bin/smbspool $out/lib/cups/backend/smb fi # Provide support for printing via HTTPS. if [ ! -e ${pkgs.cups}/lib/cups/backend/https ]; then mkdir -p $out/lib/cups/backend ln -sv ${pkgs.cups}/lib/cups/backend/ipp $out/lib/cups/backend/https fi # Import filter configuration from Ghostscript. mkdir -p $out/share/cups/mime/ ln -v -s "${pkgs.ghostscript}/etc/cups/"* $out/share/cups/mime/ ''; # Here we can enable additional backends, filters, etc. that are not # part of CUPS itself, e.g. the SMB backend is part of Samba. Since # we can't update ${cups}/lib/cups itself, we create a symlink tree # here and add the additional programs. The ServerBin directive in # cupsd.conf tells cupsd to use this tree. bindir = pkgs.buildEnv { name = "cups-progs"; paths = cfg.drivers; pathsToLink = [ "/lib/cups" "/share/cups" "/bin" "/etc/cups" ]; postBuild = cfg.bindirCmds; }; in { ###### interface options = { services.printing = { enable = mkOption { type = types.bool; default = false; description = '' Whether to enable printing support through the CUPS daemon. ''; }; listenAddresses = mkOption { type = types.listOf types.str; default = [ "127.0.0.1:631" ]; example = [ "*:631" ]; description = '' A list of addresses and ports on which to listen. ''; }; bindirCmds = mkOption { type = types.lines; internal = true; default = ""; description = '' Additional commands executed while creating the directory containing the CUPS server binaries. ''; }; cupsdConf = mkOption { type = types.lines; default = ""; example = '' BrowsePoll cups.example.com LogLevel debug ''; description = '' The contents of the configuration file of the CUPS daemon (cupsd.conf). ''; }; clientConf = mkOption { type = types.lines; default = ""; example = '' ServerName server.example.com Encryption Never ''; description = '' The contents of the client configuration. (client.conf) ''; }; drivers = mkOption { type = types.listOf types.path; example = literalExample "[ pkgs.splix ]"; description = '' CUPS drivers to use. Drivers provided by CUPS, Ghostscript and Samba are added unconditionally. ''; }; tempDir = mkOption { type = types.path; default = "/tmp"; example = "/tmp/cups"; description = '' CUPSd temporary directory. ''; }; }; }; ###### implementation config = mkIf config.services.printing.enable { users.extraUsers = singleton { name = "cups"; uid = config.ids.uids.cups; group = "lp"; description = "CUPS printing services"; }; environment.systemPackages = [ cups ]; environment.variables.CUPS_SERVERROOT = "/etc/cups"; environment.etc = [ { source = pkgs.writeText "client.conf" cfg.clientConf; target = "cups/client.conf"; } ]; services.dbus.packages = [ cups ]; # Cups uses libusb to talk to printers, and does not use the # linux kernel driver. If the driver is not in a black list, it # gets loaded, and then cups cannot access the printers. boot.blacklistedKernelModules = [ "usblp" ]; systemd.services.cupsd = { description = "CUPS Printing Daemon"; wantedBy = [ "multi-user.target" ]; wants = [ "network.target" ]; after = [ "network.target" ]; path = [ cups ]; preStart = '' mkdir -m 0755 -p /etc/cups mkdir -m 0700 -p /var/cache/cups mkdir -m 0700 -p /var/spool/cups mkdir -m 0755 -p ${cfg.tempDir} ''; serviceConfig.Type = "forking"; serviceConfig.ExecStart = "@${cups}/sbin/cupsd cupsd -c ${pkgs.writeText "cupsd.conf" cfg.cupsdConf}"; }; services.printing.drivers = [ pkgs.cups pkgs.cups_pdf_filter pkgs.ghostscript additionalBackends pkgs.perl pkgs.coreutils pkgs.gnused pkgs.bc pkgs.gawk pkgs.gnugrep ]; services.printing.cupsdConf = '' LogLevel info SystemGroup root wheel ${concatMapStrings (addr: '' Listen ${addr} '') cfg.listenAddresses} Listen /var/run/cups/cups.sock # Note: we can't use ${cups}/etc/cups as the ServerRoot, since # CUPS will write in the ServerRoot when e.g. adding new printers # through the web interface. ServerRoot /etc/cups ServerBin ${bindir}/lib/cups DataDir ${bindir}/share/cups SetEnv PATH ${bindir}/lib/cups/filter:${bindir}/bin:${bindir}/sbin AccessLog syslog ErrorLog syslog PageLog syslog TempDir ${cfg.tempDir} # User and group used to run external programs, including # those that actually send the job to the printer. Note that # Udev sets the group of printer devices to `lp', so we want # these programs to run as `lp' as well. User cups Group lp Browsing On BrowseOrder allow,deny BrowseAllow @LOCAL DefaultAuthType Basic Order allow,deny Allow localhost Order allow,deny Allow localhost AuthType Basic Require user @SYSTEM Order allow,deny Allow localhost Require user @OWNER @SYSTEM Order deny,allow AuthType Basic Require user @SYSTEM Order deny,allow Require user @OWNER @SYSTEM Order deny,allow Order deny,allow ''; security.pam.services.cups = {}; }; }