configure shutdown instructions in runit stage 3

flake.nix

@@ -19,6 +19,7 @@
           ./pr-28.patch
           ./pr-29.patch
           ./pr-30.patch
+          ./pr-31.patch
         ];
       };
 

pr-31.patch

@@ -0,0 +1,28 @@
+diff --git a/runit.nix b/runit.nix
+index d7b0bf3..64f99f2 100644
+--- a/runit.nix
++++ b/runit.nix
+@@ -57,6 +57,23 @@ in
+       '';
+       "runit/3".source = pkgs.writeScript "3" ''
+         #!${pkgs.runtimeShell}
++        echo Waiting for services to stop...
++        sv force-stop /etc/service/*
++        sv exit /etc/service/*
++
++        echo Sending TERM signal to processes...
++        pkill --inverse -s0,1 -TERM
++        sleep 1
++        echo Sending KILL signal to processes...
++        pkill --inverse -s0,1 -KILL
++
++        echo Unmounting filesystems, disabling swap...
++        swapoff -a
++        umount -r -a -t nosysfs,noproc,nodevtmpfs,notmpfs
++        echo Remounting rootfs read-only...
++        mount -o remount,ro /
++
++        sync
+         echo and down we go
+       '';
+       "service/sshd/run".source = pkgs.writeScript "sshd_run" ''