infrastructure/modules/nixos/samba.nix

{
  config,
  lib,
  pkgs,
  ...
}: let
  inherit (lib.options) mkOption mkEnableOption;
  inherit (lib.modules) mkIf mkMerge mkDefault mkOptionDefault;
  inherit (lib.attrsets) mapAttrs' mapAttrsToList nameValuePair;
  inherit (lib.strings) hasPrefix concatMapStringsSep;
  inherit (config.services) samba-wsdd;
  cfg = config.services.samba;
  settingValue = value:
    if builtins.isList value then concatMapStringsSep ", " settingValue value
    else if value == true then "yes"
    else if value == false then "no"
    else toString value;
in {
  options.services.samba = with lib.types; let
    settingPrimitive = oneOf [ str int bool ];
    settingType = oneOf [ settingPrimitive (listOf settingPrimitive) ];
  in {
    ldap = {
      enable = mkEnableOption "LDAP";
      idmapDomain = mkOption {
        type = str;
        default = "*";
      };
      url = mkOption {
        type = str;
      };
      baseDn = mkOption {
        type = str;
      };
      adminDn = mkOption {
        type = str;
        default = "name=anonymous,${cfg.ldap.baseDn}";
      };
      adminPasswordPath = mkOption {
        type = nullOr path;
        default = null;
      };
    };
    usershare = {
      enable = mkEnableOption "usershare";
      group = mkOption {
        type = str;
        default = "users";
      };
      path = mkOption {
        type = path;
        default = "/var/lib/samba/usershares";
      };
      templateShare = mkOption {
        type = str;
        default = "usershare-template";
      };
    };
    guest = {
      enable = mkEnableOption "guest account";
      user = mkOption {
        type = str;
        default = "nobody";
      };
    };
    idmap = let
      idmapModule = { config, name, ... }: {
        options = {
          backend = mkOption {
            type = str;
          };
          domain = mkOption {
            type = str;
            default = name;
          };
          range = {
            min = mkOption {
              type = int;
              default = 1000;
            };
            max = mkOption {
              type = int;
              default = 10000;
            };
          };
          readOnly = mkOption {
            type = bool;
            default = true;
          };
          settings = mkOption {
            type = attrsOf settingType;
            default = { };
          };
        };
        config = {
          settings = {
            backend = mkOptionDefault config.backend;
            "read only" = mkOptionDefault config.readOnly;
            range = mkOptionDefault "${toString config.range.min} - ${toString config.range.max}";
          };
        };
      };
    in {
      domains = mkOption {
        type = attrsOf (submodule idmapModule);
        default = {
          nss = {
            backend = "nss";
            domain = "*";
          };
        };
      };
    };
    passdb.smbpasswd.path = mkOption {
      type = nullOr path;
      default = null;
    };
    settings = mkOption {
      type = attrsOf settingType;
      default = { };
    };
  };

  config = {
    services.samba = {
      package = mkIf cfg.ldap.enable (mkDefault (pkgs.samba.override {
        enableLDAP = true;
      }));
      ldap = {
        adminPasswordPath = mkIf (hasPrefix "name=anonymous," cfg.ldap.adminDn) (mkDefault (
          pkgs.writeText "smb-ldap-anonymous" "anonymous"
        ));
      };
      idmap.domains = mkMerge [
        (mkIf cfg.ldap.enable {
          ldap = {
            domain = mkDefault cfg.ldap.idmapDomain;
          };
        })
      ];
      settings = mkMerge ([
        {
          "use sendfile" = mkOptionDefault true;
        }
        (mkIf (cfg.passdb.smbpasswd.path != null) {
          "passdb backend" = mkOptionDefault "smbpasswd:${cfg.passdb.smbpasswd.path}";
        })
        (mkIf cfg.ldap.enable {
          "passdb backend" = mkOptionDefault ''ldapsam:"${cfg.ldap.url}"'';
          "ldap ssl" = mkIf (hasPrefix "ldaps://" cfg.ldap.url) (mkOptionDefault "off");
          "ldap admin dn" = mkOptionDefault "name=anonymous,${cfg.ldap.baseDn}";
          "ldap suffix" = mkOptionDefault cfg.ldap.baseDn;
        })
        (mkIf (cfg.ldap.enable && true) {
          "ntlm auth" = mkOptionDefault "disabled";
          "encrypt passwords" = mkOptionDefault false;
        })
        (mkIf cfg.usershare.enable {
          "usershare allow guests" = mkOptionDefault true;
          "usershare max shares" = mkOptionDefault 16;
          "usershare owner only" = mkOptionDefault true;
          "usershare template share" = mkOptionDefault cfg.usershare.templateShare;
          "usershare path" = mkOptionDefault cfg.usershare.path;
          "usershare prefix allow list" = mkOptionDefault [ cfg.usershare.path ];
        })
        (mkIf cfg.guest.enable {
          "map to guest" = mkOptionDefault "Bad User";
          "guest account" = mkOptionDefault cfg.guest.user;
        })
      ] ++ mapAttrsToList (_: idmap: mapAttrs' (key: value: nameValuePair "idmap config ${idmap.domain} : ${key}" (mkOptionDefault value)) idmap.settings) cfg.idmap.domains);
      extraConfig = mkMerge (mapAttrsToList (key: value: ''${key} = ${settingValue value}'') cfg.settings);
      shares.${cfg.usershare.templateShare} = mkIf cfg.usershare.enable {
        "-valid" = false;
      };
    };

    systemd.services.samba-smbd = mkIf cfg.enable {
      serviceConfig = let
        ldap-pass = pkgs.writeShellScript "samba-ldap-pass" ''
          ${cfg.package}/bin/smbpasswd -c /etc/samba/smb.conf -w $(cat ${cfg.ldap.adminPasswordPath})
        '';
      in {
        ExecStartPre = mkMerge [
          (mkIf (cfg.ldap.enable && cfg.ldap.adminPasswordPath != null) [
            "${ldap-pass}"
          ])
        ];
      };
    };

    systemd.tmpfiles.rules = mkIf (cfg.enable && cfg.usershare.enable) [
      "d ${cfg.usershare.path} 1770 root ${cfg.usershare.group}"
    ];

    networking.firewall.interfaces.local = {
      allowedTCPPorts = mkMerge [
        (mkIf (cfg.enable && !cfg.openFirewall) [ 139 445 ])
        (mkIf (samba-wsdd.enable && !samba-wsdd.openFirewall) [ 5357 ])
      ];
      allowedUDPPorts = mkMerge [
        (mkIf (cfg.enable && !cfg.openFirewall) [ 137 138 ])
        (mkIf (samba-wsdd.enable && !samba-wsdd.openFirewall) [ 3702 ])
      ];
    };
  };
}