From dd124e49dd203f300b4ae4b8074755dbe1735e4e Mon Sep 17 00:00:00 2001
From: Daniel Barlow <dan@telent.net>
Date: Thu, 22 Sep 2022 12:42:20 +0100
Subject: [PATCH] udhcp: write service responses as outputs

---
 pkgs/liminix-tools/default.nix           |  2 +-
 pkgs/liminix-tools/networking/udhcpc.nix | 51 +++++++++++++++++++++++-
 2 files changed, 50 insertions(+), 3 deletions(-)

diff --git a/pkgs/liminix-tools/default.nix b/pkgs/liminix-tools/default.nix
index 0b7d30e0..1d0ba90d 100644
--- a/pkgs/liminix-tools/default.nix
+++ b/pkgs/liminix-tools/default.nix
@@ -80,6 +80,6 @@ in {
   };
   services = {
     inherit longrun oneshot bundle target;
-    output = service: name: "/run/services/outputs/${service.name}/${name}";
+    output = service: name: "/run/s6-rc/scandir/${service.name}/data/outputs/${name}";
   };
 }
diff --git a/pkgs/liminix-tools/networking/udhcpc.nix b/pkgs/liminix-tools/networking/udhcpc.nix
index ffdecb84..5ce05a63 100644
--- a/pkgs/liminix-tools/networking/udhcpc.nix
+++ b/pkgs/liminix-tools/networking/udhcpc.nix
@@ -1,10 +1,57 @@
 {
   liminix
 , busybox
+, writeShellScript
 } :
-let inherit (liminix.services) longrun;
+let
+  inherit (liminix.services) longrun;
+  script = writeShellScript "udhcp-notify" ''
+action=$1
+env > /run/udhcp.values
+
+set_address() {
+    ip address replace $ip/$mask dev $interface
+    mkdir -p data/outputs
+    for i in lease mask ip router siaddr dns serverid subnet opt53 interface ; do
+        echo ''${!i} > data/outputs/$i
+    done
+}
+case $action in
+  deconfig)
+    ip address flush $interface
+    ip link set up dev $interface
+    ;;
+  bound)
+    # this doesn't actually replace, it adds a new address.
+    set_address
+    ;;
+  renew)
+    set_address
+    ;;
+  nak)
+    echo "received NAK on $interface"
+    ;;
+esac
+'';
+
 in
 interface: { ... } @ args: longrun {
   name = "${interface.device}.udhcp";
-  run = "${busybox}/bin/udhcpc -f -i ${interface.device}";
+  run = "${busybox}/bin/udhcpc -f -i ${interface.device} -s ${script}";
 }
+
+# lease=86400
+# mask=24
+# ip=10.0.2.15
+# router=10.0.2.2
+# siaddr=10.0.2.2
+# dns=10.0.2.3
+# serverid=10.0.2.2
+# subnet=255.255.255.0
+# SHLVL=2
+# opt53=05
+# interface=eth0
+# PATH=/nix/store/npy692wik809z3vdwrkrj2wixjkr33kp-busybox-mips-unknown-linux-musl-1.35.0/bin:/nix/store/
+# pj0b27l5728cypa5mmagz0q8ibzpik0h-execline-mips-unknown-linux-musl-2.9.0.1-bin/bin:/nix/store/rfjiw4dnv29daqc9971qmica1h86l0s0-s6-linux-init-mips-unknown-linux-musl-1.0.8.0-bin/bin:/nix/store/4wn3jm7yy2gfi0is0yy75lifbq5zjwz7-s6-rc-mips-unknown-linux-musl-0.5.3.2-bin/bin:/usr/bin:/bin
+# _=/nix/store/npy692wik809z3vdwrkrj2wixjkr33kp-busybox-mips-unknown-linux-musl-1.35.0/bin/env
+# /