gpg-agent: add launchd service agent and sockets

This adds a Darwin Launchd agent along with its sockets to make
gpg-agent starts at load or whenever the sockets are needed.

Fixes: https://github.com/nix-community/home-manager/issues/3864

.editorconfig

@@ -19,3 +19,6 @@ indent_style = tab
 
 [*.md]
 trim_trailing_whitespace = false
+
+[*.plist]
+insert_final_newline = false

modules/services/gpg-agent.nix

@@ -30,7 +30,7 @@ let
     $env.SSH_AUTH_SOCK = ($env.SSH_AUTH_SOCK? | default (${gpgPkg}/bin/gpgconf --list-dirs agent-ssh-socket))
   '';
 
-  # mimic `gpgconf` output for use in `systemd` unit definitions.
+  # mimic `gpgconf` output for use in the service definitions.
   # we cannot use `gpgconf` directly because it heavily depends on system
   # state, but we need the values at build time. original:
   # https://github.com/gpg/gnupg/blob/c6702d77d936b3e9d91b34d8fdee9599ab94ee1b/common/homedir.c#L672-L681
@@ -38,10 +38,14 @@ let
     let
       hash =
         substring 0 24 (hexStringToBase32 (builtins.hashString "sha1" homedir));
-    in if homedir == options.programs.gpg.homedir.default then
+      subdir = if homedir == options.programs.gpg.homedir.default then
-      "%t/gnupg/${dir}"
+        "${dir}"
       else
-      "%t/gnupg/d.${hash}/${dir}";
+        "d.${hash}/${dir}";
+    in if pkgs.stdenv.isDarwin then
+      "/private/var/run/org.nix-community.home.gpg-agent/${subdir}"
+    else
+      "%t/gnupg/${subdir}";
 
   # Act like `xxd -r -p | base32` but with z-base-32 alphabet and no trailing padding.
   # Written in Nix for purity.
@@ -77,6 +81,32 @@ let
       };
   in hexString: (foldl' go initState (stringToCharacters hexString)).ret;
 
+  # Systemd socket unit generator.
+  mkSocket = { desc, docs, stream, fdName }: {
+    Unit = {
+      Description = desc;
+      Documentation = docs;
+    };
+
+    Socket = {
+      ListenStream = gpgconf "${stream}";
+      FileDescriptorName = "${fdName}";
+      Service = "gpg-agent.service";
+      SocketMode = "0600";
+      DirectoryMode = "0700";
+    };
+
+    Install = { WantedBy = [ "sockets.target" ]; };
+  };
+
+  # Launchd agent socket generator.
+  mkAgentSock = name: {
+    SockType = "stream";
+    SockPathName = gpgconf name;
+    SockPathMode =
+      384; # Property lists don't support octal literals (0600 = 384).
+  };
+
 in {
   meta.maintainers = [ maintainers.rycee ];
 
@@ -272,17 +302,8 @@ in {
       '') cfg.sshKeys;
     })
 
-    # The systemd units below are direct translations of the
+    (mkMerge [
-    # descriptions in the
+      (mkIf pkgs.stdenv.isLinux {
-    #
-    #   ${gpgPkg}/share/doc/gnupg/examples/systemd-user
-    #
-    # directory.
-    {
-      assertions = [
-        (hm.assertions.assertPlatform "services.gpg-agent" pkgs platforms.linux)
-      ];
-
         systemd.user.services.gpg-agent = {
           Unit = {
             Description = "GnuPG cryptographic agent and passphrase cache";
@@ -301,61 +322,54 @@ in {
           };
         };
 
-      systemd.user.sockets.gpg-agent = {
+        systemd.user.sockets.gpg-agent = mkSocket {
-        Unit = {
+          desc = "GnuPG cryptographic agent and passphrase cache";
-          Description = "GnuPG cryptographic agent and passphrase cache";
+          docs = "man:gpg-agent(1)";
-          Documentation = "man:gpg-agent(1)";
+          stream = "S.gpg-agent";
+          fdName = "std";
         };
 
-        Socket = {
+        systemd.user.sockets.gpg-agent-ssh = mkIf cfg.enableSshSupport
-          ListenStream = gpgconf "S.gpg-agent";
+          (mkSocket ({
-          FileDescriptorName = "std";
+            desc = "GnuPG cryptographic agent (ssh-agent emulation)";
-          SocketMode = "0600";
+            docs =
-          DirectoryMode = "0700";
-        };
-
-        Install = { WantedBy = [ "sockets.target" ]; };
-      };
-    }
-
-    (mkIf cfg.enableSshSupport {
-      systemd.user.sockets.gpg-agent-ssh = {
-        Unit = {
-          Description = "GnuPG cryptographic agent (ssh-agent emulation)";
-          Documentation =
               "man:gpg-agent(1) man:ssh-add(1) man:ssh-agent(1) man:ssh(1)";
-        };
+            stream = "S.gpg-agent.ssh";
+            fdName = "ssh";
+          }));
 
-        Socket = {
+        systemd.user.sockets.gpg-agent-extra = mkIf cfg.enableExtraSocket
-          ListenStream = gpgconf "S.gpg-agent.ssh";
+          (mkSocket {
-          FileDescriptorName = "ssh";
+            desc =
-          Service = "gpg-agent.service";
-          SocketMode = "0600";
-          DirectoryMode = "0700";
-        };
-
-        Install = { WantedBy = [ "sockets.target" ]; };
-      };
-    })
-
-    (mkIf cfg.enableExtraSocket {
-      systemd.user.sockets.gpg-agent-extra = {
-        Unit = {
-          Description =
               "GnuPG cryptographic agent and passphrase cache (restricted)";
-          Documentation = "man:gpg-agent(1) man:ssh(1)";
+            docs = "man:gpg-agent(1) man:ssh(1)";
-        };
+            stream = "S.gpg-agent.extra";
+            fdName = "extra";
+          });
+      })
 
-        Socket = {
+      (mkIf pkgs.stdenv.isDarwin {
-          ListenStream = gpgconf "S.gpg-agent.extra";
+        launchd.agents.gpg-agent = {
-          FileDescriptorName = "extra";
+          enable = true;
-          Service = "gpg-agent.service";
+          config = {
-          SocketMode = "0600";
+            ProgramArguments = [ "${gpgPkg}/bin/gpg-agent" "--supervised" ]
-          DirectoryMode = "0700";
+              ++ optional cfg.verbose "--verbose";
+            EnvironmentVariables = { GNUPGHOME = homedir; };
+            KeepAlive = {
+              Crashed = true;
+              SuccessfulExit = false;
+            };
+            ProcessType = "Background";
+            RunAtLoad = cfg.enableSshSupport;
+            Sockets = {
+              Agent = mkAgentSock "S.gpg-agent";
+              Ssh = mkIf cfg.enableSshSupport (mkAgentSock "S.gpg-agent.ssh");
+              Extra =
+                mkIf cfg.enableExtraSocket (mkAgentSock "S.gpg-agent.extra");
+            };
           };
-
-        Install = { WantedBy = [ "sockets.target" ]; };
         };
       })
+    ])
   ]);
 }

tests/default.nix

@@ -162,6 +162,7 @@ in import nmtSrc {
     ./modules/programs/zk
     ./modules/programs/zplug
     ./modules/programs/zsh
+    ./modules/services/gpg-agent
     ./modules/services/syncthing/common
     ./modules/xresources
   ] ++ lib.optionals isDarwin [
@@ -242,7 +243,6 @@ in import nmtSrc {
     ./modules/services/fusuma
     ./modules/services/git-sync
     ./modules/services/glance
-    ./modules/services/gpg-agent
     ./modules/services/gromit-mpx
     ./modules/services/home-manager-auto-upgrade
     ./modules/services/hypridle

tests/modules/services/gpg-agent/default-homedir.nix

@@ -2,7 +2,7 @@
 
 with lib;
 
-{
+mkIf pkgs.stdenv.isLinux {
   config = {
     services.gpg-agent.enable = true;
     services.gpg-agent.pinentryPackage = pkgs.pinentry-gnome3;

tests/modules/services/gpg-agent/expected-agent.plist

@@ -0,0 +1,41 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<!DOCTYPE plist PUBLIC "-//Apple Computer//DTD PLIST 1.0//EN" "http://www.apple.com/DTDs/PropertyList-1.0.dtd">
+<plist version="1.0">
+<dict>
+	<key>EnvironmentVariables</key>
+	<dict>
+		<key>GNUPGHOME</key>
+		<string>/path/to/hash</string>
+	</dict>
+	<key>KeepAlive</key>
+	<dict>
+		<key>Crashed</key>
+		<true/>
+		<key>SuccessfulExit</key>
+		<false/>
+	</dict>
+	<key>Label</key>
+	<string>org.nix-community.home.gpg-agent</string>
+	<key>ProcessType</key>
+	<string>Background</string>
+	<key>ProgramArguments</key>
+	<array>
+		<string>@gpg@/bin/gpg-agent</string>
+		<string>--supervised</string>
+	</array>
+	<key>RunAtLoad</key>
+	<false/>
+	<key>Sockets</key>
+	<dict>
+		<key>Agent</key>
+		<dict>
+			<key>SockPathMode</key>
+			<integer>384</integer>
+			<key>SockPathName</key>
+			<string>/private/var/run/org.nix-community.home.gpg-agent/d.wp4h7ks5zxy4dodqadgpbbpz/S.gpg-agent</string>
+			<key>SockType</key>
+			<string>stream</string>
+		</dict>
+	</dict>
+</dict>
+</plist>

tests/modules/services/gpg-agent/override-homedir.nix

@@ -2,19 +2,25 @@
 
 with lib;
 
-{
+let inherit (pkgs.stdenv) isDarwin;
+in {
   config = {
     services.gpg-agent.enable = true;
     services.gpg-agent.pinentryPackage = null; # Don't build pinentry package.
     programs.gpg = {
       enable = true;
       homedir = "/path/to/hash";
+      package = config.lib.test.mkStubPackage { outPath = "@gpg@"; };
     };
 
     test.stubs.gnupg = { };
     test.stubs.systemd = { }; # depends on gnupg.override
 
-    nmt.script = ''
+    nmt.script = if isDarwin then ''
+      serviceFile=LaunchAgents/org.nix-community.home.gpg-agent.plist
+      assertFileExists "$serviceFile"
+      assertFileContent "$serviceFile" ${./expected-agent.plist}
+    '' else ''
       in="${config.systemd.user.sockets.gpg-agent.Socket.ListenStream}"
       if [[ $in != "%t/gnupg/d.wp4h7ks5zxy4dodqadgpbbpz/S.gpg-agent" ]]
       then