make s6-init-files into a module

modules/s6/default.nix

@@ -0,0 +1,158 @@
+{ config, pkgs, ... }:
+let
+  inherit (pkgs)
+    busybox
+    execline
+    s6
+    s6-init-bin
+    s6-linux-init
+    stdenvNoCC;
+  inherit (pkgs.pseudofile) dir symlink;
+
+  s6-rc-db = pkgs.s6-rc-database.override {
+    services = builtins.attrValues config.services;
+  };
+  s6-init-scripts = stdenvNoCC.mkDerivation {
+    name = "s6-scripts";
+    src = ./scripts;
+    phases = ["unpackPhase" "installPhase" ];
+    buildInputs = [busybox];
+    installPhase = ''
+      mkdir $out
+      cp -r $src $out/scripts
+      chmod -R +w $out
+      patchShebangs $out/scripts
+    '';
+  };
+  service = dir  {
+    s6-linux-init-runleveld = dir {
+      notification-fd = { file = "3"; };
+      run = {
+        file = ''
+              #!${execline}/bin/execlineb -P
+              ${execline}/bin/fdmove -c 2 1
+              ${execline}/bin/fdmove 1 3
+              ${s6}/bin/s6-ipcserver -1 -a 0700 -c 1 -- s
+              ${s6}/bin/s6-sudod -dt30000 -- "/etc/s6-linux-init/current"/scripts/runlevel
+            '';
+        mode = "0755";
+      };
+    };
+    s6-linux-init-shutdownd = dir {
+      fifo = {
+        type = "i";
+        subtype = "f";
+        mode = "0600";
+      };
+      run = {
+        file = ''
+              #!${execline}/bin/execlineb -P
+              ${s6-linux-init}/bin/s6-linux-init-shutdownd -c  "/etc/s6-linux-init/current" -g 3000
+            '';
+        mode = "0755";
+      };
+    };
+    s6-svscan-log = dir {
+      fifo = {
+        type = "i";
+        subtype = "f";
+        mode = "0600";
+      };
+      notification-fd = { file = "3"; };
+      run = {
+        file = ''
+              #!${execline}/bin/execlineb -P
+              ${execline}/bin/redirfd -w 1 /dev/null
+              ${execline}/bin/redirfd -rnb 0 fifo
+              ${s6}/bin/s6-log -bpd3 -- t /run/uncaught-logs
+          '';
+        mode = "0755";
+      };
+    };
+    getty = dir {
+      run = {
+        file = ''
+              #!${execline}/bin/execlineb -P
+              ${busybox}/bin/getty -l ${busybox}/bin/login 38400 /dev/console
+          '';
+        mode = "0755";
+      };
+    };
+    ".s6-svscan" =
+      let
+        quit = message: ''
+              #!${execline}/bin/execlineb -P
+              ${execline}/bin/redirfd -w 2 /dev/console
+              ${execline}/bin/fdmove -c 1 2
+              ${execline}/bin/foreground { ${s6-linux-init}/bin/s6-linux-init-echo -- ${message} }
+              ${s6-linux-init}/bin/s6-linux-init-hpr -fr
+            '';
+        shutdown = action: ''
+              #!${execline}/bin/execlineb -P
+              ${s6-linux-init}/bin/s6-linux-init-hpr -a #{action} -- now
+            '';
+        empty = "#!${execline}/bin/execlineb -P\n";
+      in dir {
+        crash = {
+          file = quit "s6-svscan crashed. Rebooting.";
+          mode = "0755";
+        };
+        finish = {
+          file = quit "s6-svscan exited. Rebooting.";
+          mode = "0755";
+        };
+        SIGINT = {
+          file = shutdown "-r";
+          mode = "0755";
+        };
+        SIGPWR = {
+          file = shutdown "-p";
+          mode = "0755";
+        };
+        SIGQUIT = {
+          file = empty;
+          mode = "0755";
+        };
+        SIGTERM = {
+          file = empty;
+          mode = "0755";
+        };
+        SIGUSR1 = {
+          file = shutdown "-p";
+          mode = "0755";
+        };
+        SIGUSR2 = {
+          file = shutdown "-h";
+          mode = "0755";
+        };
+        SIGWINCH = {
+          file = empty;
+          mode = "0755";
+        };
+
+      };
+  };
+in {
+  config = {
+    environment = dir {
+      etc = dir {
+        s6-rc = dir {
+          compiled = symlink "${s6-rc-db}/compiled";
+        };
+        s6-linux-init = dir {
+          current = dir {
+            scripts = symlink "${s6-init-scripts}/scripts";
+            env = dir {};
+            run-image = dir {
+              uncaught-logs = (dir {}) // {mode = "2750";};
+              inherit service;
+            };
+          };
+        };
+      };
+      bin = dir {
+        init = symlink "${s6-init-bin}/bin/init";
+      };
+    };
+  };
+}

modules/s6/scripts/rc.init

@@ -0,0 +1,45 @@
+#!/usr/bin/env sh
+
+rl="$1"
+shift
+
+### argv now contains the arguments of the kernel command line that are
+### not of the form key=value. (The key=value arguments were stored by
+### s6-linux-init into an envdir, if instructed so via the -s option.)
+### Normally this argv remains unused because programs that need the
+### kernel command line usually read it later on from /proc/cmdline -
+### but just in case, it's available here.
+
+
+### 1. Early preparation
+### This is done only once at boot time.
+### Ideally, this phase should just initialize the service manager.
+
+mount -t proc none /proc
+mount -t sysfs none /sys
+
+### If your services are managed by s6-rc:
+### (replace /run/service with your scandir)
+s6-rc-init /run/service -d -c /etc/s6-rc/compiled
+
+
+### 2. Starting the wanted set of services
+### This is also called every time you change runlevels with telinit.
+### (edit the location to suit your installation)
+### By default, $rl is the string "default", unless you changed it
+### via the -D option to s6-linux-init-maker.
+### Numeric arguments from 1 to 5 on the kernel command line will
+### override the default.
+
+exec /etc/s6-linux-init/current/scripts/runlevel "$rl"
+
+
+### If this script is run in a container, then 1. and 2. above do not
+### apply and you should just call your CMD, if any, or let your
+### services run.
+### Something like this:
+
+# if test -z "$*" ; then return 0 ; fi
+# $@
+# echo $? > /run/s6-linux-init-container-results/exitcode
+# halt

modules/s6/scripts/rc.shutdown

@@ -0,0 +1,19 @@
+#!/usr/bin/env sh
+
+
+### Things to do before hardware halt/reboot/poweroff.
+### Ideally, it should be a single call to the service manager,
+### telling it to bring all the services down.
+
+### If your s6-linux-init-maker invocation was made with the -1
+### option, messages from rc.shutdown will appear on /dev/console
+### as well as be logged by the catch-all logger.
+### If your s6-linux-init-maker invocation did NOT include the -1
+### option, messages from rc.shutdown will only be logged by the
+### catch-all logger and will NOT appear on /dev/console. In order
+### to print them to /dev/console instead, you may want to
+### uncomment the following line:
+exec >/dev/console 2>&1
+
+### If your services are managed by s6-rc:
+exec s6-rc -v2 -bDa change

modules/s6/scripts/rc.shutdown.final

@@ -0,0 +1,18 @@
+#!/nix/store/xbdqbi2mscmhl5wcpbgpjdwxbsrvpkil-bash-5.1-p16/bin/sh -e
+
+### Things to do *right before* the machine gets rebooted or
+### powered off, at the very end of the shutdown sequence,
+### when all the filesystems are unmounted.
+
+### This is a last resort hook; normally nothing should be
+### done here (your rc.shutdown script should have taken care
+### of everything) and you should leave this script empty.
+
+### Some distributions, however, may need to perform some
+### actions after unmounting the filesystems: typically if
+### an additional teardown action is required on a filesystem
+### after unmounting it, or if the system needs to be
+### pivot_rooted before it can be shut down, etc.
+
+### Those are all exceptional cases. If you don't know for
+### certain that you need to do something here, you don't.

modules/s6/scripts/runlevel

@@ -0,0 +1,12 @@
+#!/usr/bin/env sh -e
+
+### This script is called once at boot time by rc.init, and is
+### also called by the runleveld service every time the user
+### requests a machine state change via telinit.
+### Ideally, it should just be a call to the service manager.
+
+test "$#" -gt 0 || { echo 'runlevel: fatal: too few arguments' 1>&2 ; exit 100 ; }
+
+
+### If your services are managed by s6-rc:
+exec s6-rc -v2 -up change "$1"