From b4bacff13f020ad742800a1dc9f0f163af7dd9d4 Mon Sep 17 00:00:00 2001
From: Tad Fisher <tadfisher@gmail.com>
Date: Wed, 18 Dec 2019 16:02:41 -0800
Subject: nixos/keybase, nixos/kbfs: update service configs; add redirector

---
 .../modules/services/network-filesystems/kbfs.nix  | 90 +++++++++++++++++-----
 1 file changed, 71 insertions(+), 19 deletions(-)

(limited to 'nixos/modules/services/network-filesystems/kbfs.nix')

diff --git a/nixos/modules/services/network-filesystems/kbfs.nix b/nixos/modules/services/network-filesystems/kbfs.nix
index 263b70d04a5..a43ac656f66 100644
--- a/nixos/modules/services/network-filesystems/kbfs.nix
+++ b/nixos/modules/services/network-filesystems/kbfs.nix
@@ -1,6 +1,7 @@
 { config, lib, pkgs, ... }:
 with lib;
 let
+  inherit (config.security) wrapperDir;
   cfg = config.services.kbfs;
 
 in {
@@ -17,6 +18,16 @@ in {
         description = "Whether to mount the Keybase filesystem.";
       };
 
+      enableRedirector = mkOption {
+        type = types.bool;
+        default = false;
+        description = ''
+          Whether to enable the Keybase root redirector service, allowing
+          any user to access KBFS files via <literal>/keybase</literal>,
+          which will show different contents depending on the requester.
+        '';
+      };
+
       mountPoint = mkOption {
         type = types.str;
         default = "%h/keybase";
@@ -41,26 +52,67 @@ in {
 
   ###### implementation
 
-  config = mkIf cfg.enable {
-
-    systemd.user.services.kbfs = {
-      description = "Keybase File System";
-      requires = [ "keybase.service" ];
-      after = [ "keybase.service" ];
-      path = [ "/run/wrappers" ];
-      unitConfig.ConditionUser = "!@system";
-      serviceConfig = {
-        ExecStartPre = "${pkgs.coreutils}/bin/mkdir -p ${cfg.mountPoint}";
-        ExecStart = "${pkgs.kbfs}/bin/kbfsfuse ${toString cfg.extraFlags} ${cfg.mountPoint}";
-        ExecStopPost = "/run/wrappers/bin/fusermount -u ${cfg.mountPoint}";
-        Restart = "on-failure";
-        PrivateTmp = true;
+  config = mkIf cfg.enable (mkMerge [
+    {
+      # Upstream: https://github.com/keybase/client/blob/master/packaging/linux/systemd/kbfs.service
+      systemd.user.services.kbfs = {
+        description = "Keybase File System";
+
+        # Note that the "Requires" directive will cause a unit to be restarted whenever its dependency is restarted.
+        # Do not issue a hard dependency on keybase, because kbfs can reconnect to a restarted service.
+        # Do not issue a hard dependency on keybase-redirector, because it's ok if it fails (e.g., if it is disabled).
+        wants = [ "keybase.service" ] ++ optional cfg.enableRedirector "keybase-redirector.service";
+        path = [ "/run/wrappers" ];
+        unitConfig.ConditionUser = "!@system";
+
+        serviceConfig = {
+          Type = "notify";
+          # Keybase notifies from a forked process
+          EnvironmentFile = [
+            "-%E/keybase/keybase.autogen.env"
+            "-%E/keybase/keybase.env"
+          ];
+          ExecStartPre = [
+            "${pkgs.coreutils}/bin/mkdir -p \"${cfg.mountPoint}\""
+            "-${wrapperDir}/fusermount -uz \"${cfg.mountPoint}\""
+          ];
+          ExecStart = "${pkgs.kbfs}/bin/kbfsfuse ${toString cfg.extraFlags} \"${cfg.mountPoint}\"";
+          ExecStop = "${wrapperDir}/fusermount -uz \"${cfg.mountPoint}\"";
+          Restart = "on-failure";
+          PrivateTmp = true;
+        };
+        wantedBy = [ "default.target" ];
       };
-      wantedBy = [ "default.target" ];
-    };
 
-    services.keybase.enable = true;
+      services.keybase.enable = true;
 
-    environment.systemPackages = [ pkgs.kbfs ];
-  };
+      environment.systemPackages = [ pkgs.kbfs ];
+    }
+
+    (mkIf cfg.enableRedirector {
+      security.wrappers."keybase-redirector".source = "${pkgs.kbfs}/bin/redirector";
+
+      systemd.tmpfiles.rules = [ "d /keybase 0755 root root 0" ];
+
+      # Upstream: https://github.com/keybase/client/blob/master/packaging/linux/systemd/keybase-redirector.service
+      systemd.user.services.keybase-redirector = {
+        description = "Keybase Root Redirector for KBFS";
+        wants = [ "keybase.service" ];
+        unitConfig.ConditionUser = "!@system";
+
+        serviceConfig = {
+          EnvironmentFile = [
+            "-%E/keybase/keybase.autogen.env"
+            "-%E/keybase/keybase.env"
+          ];
+          # Note: The /keybase mount point is not currently configurable upstream.
+          ExecStart = "${wrapperDir}/keybase-redirector /keybase";
+          Restart = "on-failure";
+          PrivateTmp = true;
+        };
+
+        wantedBy = [ "default.target" ];
+      };
+    })
+  ]);
 }
-- 
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