From f5c53868700881084a0d132aa18e24d3b71698a3 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Niklas=20Hamb=C3=BCchen?= <mail@nh2.me>
Date: Tue, 25 Oct 2022 15:53:43 +0200
Subject: [PATCH] nixos/smokeping: Don't show `413 Forbidden` on thttpd `/`.
 Fixes #197704

---
 nixos/modules/services/networking/smokeping.nix | 11 +++++++++++
 nixos/tests/smokeping.nix                       |  2 ++
 2 files changed, 13 insertions(+)

diff --git a/nixos/modules/services/networking/smokeping.nix b/nixos/modules/services/networking/smokeping.nix
index df4f8905ec6f..3a5fb7dfb9e2 100644
--- a/nixos/modules/services/networking/smokeping.nix
+++ b/nixos/modules/services/networking/smokeping.nix
@@ -318,6 +318,17 @@ in
       description = "smokeping daemon user";
       home = smokepingHome;
       createHome = true;
+      # When `cfg.webService` is enabled, `thttpd` makes SmokePing available
+      # under `${cfg.host}:${cfg.port}/smokeping.fcgi` as per the `ln -s` below.
+      # We also want that going to `${cfg.host}:${cfg.port}` without `smokeping.fcgi`
+      # makes it easy for the user to find SmokePing.
+      # However `thttpd` does not seem to support easy redirections from `/` to `smokeping.fcgi`
+      # and only allows directory listings or `/` -> `index.html` resolution if the directory
+      # has `chmod 755` (see https://acme.com/software/thttpd/thttpd_man.html#PERMISSIONS,
+      # " directories should be 755 if you want to allow indexing").
+      # Otherwise it shows `403 Forbidden` on `/`.
+      # Thus, we need to make `smokepingHome` (which is given to `thttpd -d` below) `755`.
+      homeMode = "755";
     };
     users.groups.${cfg.user} = {};
     systemd.services.smokeping = {
diff --git a/nixos/tests/smokeping.nix b/nixos/tests/smokeping.nix
index ccacf60cfe4b..04f813964291 100644
--- a/nixos/tests/smokeping.nix
+++ b/nixos/tests/smokeping.nix
@@ -28,6 +28,8 @@ import ./make-test-python.nix ({ pkgs, ...} : {
     sm.wait_for_unit("thttpd")
     sm.wait_for_file("/var/lib/smokeping/data/Local/LocalMachine.rrd")
     sm.succeed("curl -s -f localhost:8081/smokeping.fcgi?target=Local")
+    # Check that there's a helpful page without explicit path as well.
+    sm.succeed("curl -s -f localhost:8081")
     sm.succeed("ls /var/lib/smokeping/cache/Local/LocalMachine_mini.png")
     sm.succeed("ls /var/lib/smokeping/cache/index.html")
   '';