nixpkgs/nixos/modules/services/mail/exim.nix
tv 816614bd62 nixos/exim: allow using service credentials
By settings User= to the actual Exim user, systemd will ensure that the
credentials directory will have the correct ownership, allowing users to
utilize LoadCredential=.  Exim still gets started as root (and drops
privileges) to preserve the previous behavior.
2022-12-14 16:43:46 +01:00

134 lines
3.3 KiB
Nix

{ config, lib, pkgs, ... }:
let
inherit (lib) literalExpression mkIf mkOption singleton types;
inherit (pkgs) coreutils;
cfg = config.services.exim;
in
{
###### interface
options = {
services.exim = {
enable = mkOption {
type = types.bool;
default = false;
description = lib.mdDoc "Whether to enable the Exim mail transfer agent.";
};
config = mkOption {
type = types.lines;
default = "";
description = lib.mdDoc ''
Verbatim Exim configuration. This should not contain exim_user,
exim_group, exim_path, or spool_directory.
'';
};
user = mkOption {
type = types.str;
default = "exim";
description = lib.mdDoc ''
User to use when no root privileges are required.
In particular, this applies when receiving messages and when doing
remote deliveries. (Local deliveries run as various non-root users,
typically as the owner of a local mailbox.) Specifying this value
as root is not supported.
'';
};
group = mkOption {
type = types.str;
default = "exim";
description = lib.mdDoc ''
Group to use when no root privileges are required.
'';
};
spoolDir = mkOption {
type = types.path;
default = "/var/spool/exim";
description = lib.mdDoc ''
Location of the spool directory of exim.
'';
};
package = mkOption {
type = types.package;
default = pkgs.exim;
defaultText = literalExpression "pkgs.exim";
description = lib.mdDoc ''
The Exim derivation to use.
This can be used to enable features such as LDAP or PAM support.
'';
};
queueRunnerInterval = mkOption {
type = types.str;
default = "5m";
description = lib.mdDoc ''
How often to spawn a new queue runner.
'';
};
};
};
###### implementation
config = mkIf cfg.enable {
environment = {
etc."exim.conf".text = ''
exim_user = ${cfg.user}
exim_group = ${cfg.group}
exim_path = /run/wrappers/bin/exim
spool_directory = ${cfg.spoolDir}
${cfg.config}
'';
systemPackages = [ cfg.package ];
};
users.users.${cfg.user} = {
description = "Exim mail transfer agent user";
uid = config.ids.uids.exim;
group = cfg.group;
};
users.groups.${cfg.group} = {
gid = config.ids.gids.exim;
};
security.wrappers.exim =
{ setuid = true;
owner = "root";
group = "root";
source = "${cfg.package}/bin/exim";
};
systemd.services.exim = {
description = "Exim Mail Daemon";
wantedBy = [ "multi-user.target" ];
restartTriggers = [ config.environment.etc."exim.conf".source ];
serviceConfig = {
ExecStart = "+${cfg.package}/bin/exim -bdf -q${cfg.queueRunnerInterval}";
ExecReload = "+${coreutils}/bin/kill -HUP $MAINPID";
User = cfg.user;
};
preStart = ''
if ! test -d ${cfg.spoolDir}; then
${coreutils}/bin/mkdir -p ${cfg.spoolDir}
${coreutils}/bin/chown ${cfg.user}:${cfg.group} ${cfg.spoolDir}
fi
'';
};
};
}