Move s6 higher in the supervision chain

 - Better s6 layout, with a place for early services and a
place for packages to add their services later on.
 - s6-svscan is now supervised by sysvinit (instead of being
run once by openrc)
 - s6-svscan is now the only process supervised by sysvinit.
All the other "respawn" lines are delegated to s6.
 - utmpd and wtmpd are now early services instead of being
added by openrc.

 These changes implement a full supervision architecture and
make init more flexible. Later on, it will be easier to
 - add conditional gettys (for /dev/hvc0...)
 - remove sysvinit entirely
 - decouple the init process from the service manager.

7 files changed, 74 insertions, 41 deletions

diff --git a/system/s6/APKBUILD b/system/s6/APKBUILD
index 77a123cd9..14ae3ba07 100644
--- a/system/s6/APKBUILD
+++ b/system/s6/APKBUILD
@@ -2,19 +2,18 @@
 # Maintainer: Laurent Bercot <ska-devel@skarnet.org>
 pkgname=s6
 pkgver=2.7.1.1
-pkgrel=0
+pkgrel=4
 pkgdesc="skarnet.org's small & secure supervision software suite"
 url="https://skarnet.org/software/$pkgname/"
 arch="all"
 options="!check"  # No test suite.
 license="ISC"
 makedepends="skalibs-dev execline-dev"
-install="s6.pre-install s6.pre-upgrade"
-subpackages="$pkgname-dev $pkgname-doc $pkgname-openrc"
-triggers="s6.trigger=/run/service"
+install="$pkgname.pre-install $pkgname.pre-upgrade $pkgname.post-upgrade"
+subpackages="$pkgname-dev $pkgname-doc"
+triggers="$pkgname.trigger=/run/service"
 source="https://skarnet.org/software/$pkgname/$pkgname-$pkgver.tar.gz
-	s6-svscanboot
-	s6.initd"
+	s6-svscanboot agetty-run"
 
 
 build() {
@@ -33,9 +32,17 @@ package() {
 	cd "$builddir"
 	make DESTDIR="$pkgdir" install
         cp -f "$srcdir/s6-svscanboot" "$pkgdir/lib/s6/s6-svscanboot"
-        mkdir -p "$pkgdir/etc/init.d"
-        cp -f "$srcdir/s6.initd" "$pkgdir/etc/init.d/s6"
-        chmod 0755 "$pkgdir/lib/s6/s6-svscanboot" "$pkgdir/etc/init.d/s6"
+	mkdir -p -m 0755 "$pkgdir/etc/s6/early-services" "$pkgdir/var/lib/s6/services"
+        chmod 0755 "$pkgdir/lib/s6/s6-svscanboot"
+
+
+	# The getty scripts are created here
+
+	for i in 1 2 3 4 5 6 ; do
+		mkdir -m 0755 "$pkgdir/etc/s6/early-services/getty-$i"
+		sed -e "s/%TTY%/tty$i/g" < "$srcdir/agetty-run" > "$pkgdir/etc/s6/early-services/getty-$i/run"
+		chmod 0755 "$pkgdir/etc/s6/early-services/getty-$i/run"
+	done
 }
 
 doc() {
@@ -45,5 +52,5 @@ doc() {
 }
 
 sha512sums="59b0a611eaa0bbdeae3133a182e933e14806151d3b8d44c7f4258a63693cf2fa487fce91a4ea37527ed0f52f211a5391b3fcf6202773b0a80d6ce7f3de60ff79  s6-2.7.1.1.tar.gz
-871ca1f86b354b7c63ce1d3bef8794627e176f993144ed67a17d0a069f5ac2164d94aba980711f61ad349dcd4fe2bf928195f2121a75e611c9897d73f1af12a0  s6-svscanboot
-e7f4fcdc04fc7f72df4419018d048e14f80d50d01ebc284b6d208d6bada3201ca91be0a110930618a26fb0e6bcc1603de01467f6f1dc635c8dcae60f1a0b1b9b  s6.initd"
+b4919f76498f86257e13210010a84284dd8574db062b96bcc527c0c5dcc2a35716ff0f3c4d23cb3ec7eed416f16aeec31247b1fda3bd06c1a8f6fd65cf32c6da  s6-svscanboot
+fb60b841da03583ba9f0f0541b45e4cf88fa5311b26376042e951317428dcaa6c81bb6c739c7a442ef0d36e1581a29cb9c4fb2d87411268fb23a033130fc8051  agetty-run"
diff --git a/system/s6/agetty-run b/system/s6/agetty-run
new file mode 100644
index 000000000..79884efc7
--- /dev/null
+++ b/system/s6/agetty-run
@@ -0,0 +1,2 @@
+#!/bin/execlineb -P
+/sbin/agetty 38400 %TTY% linux
diff --git a/system/s6/s6-svscanboot b/system/s6/s6-svscanboot
index 2b41d2916..447a1a01b 100644
--- a/system/s6/s6-svscanboot
+++ b/system/s6/s6-svscanboot
@@ -1,21 +1,53 @@
-#!/bin/execlineb -S1
+#!/bin/execlineb -P
 
-foreground { redirfd -w 2 /dev/null mkdir -p /run/uncaught-logs }
+# Basic sanity.
+
+export PATH /usr/bin:/usr/sbin:/bin:/sbin
+umask 022
+
+
+# The live service directories are in /run/services
+# The scandir is /run/service, containing only the catch-all logger and symlinks
+# (and the s6-svscan configuration in /run/service/.s6-svscan)
+
+if { rm -rf /run/service /run/services }
+if { mkdir -p -m 0755 /run/service/.s6-svscan /run/service/s6-svscan-log }
+if { ln -sf /bin/false /run/service/.s6-svscan/crash }
+if
+{
+  redirfd -w 1 /run/service/.s6-svscan/finish
+  heredoc 0 "#!/bin/execlineb -P\ns6-svc -X -- \"/run/service/s6-svscan-log\"\n"
+  cat
+}
+if { chmod 0755 /run/service/.s6-svscan/finish }
+
+
+# Directory for the catch-all logger to store its logs
+
+if { mkdir -p -m 2700 /run/uncaught-logs }
 if { chown catchlog:catchlog /run/uncaught-logs }
 if { chmod 2700 /run/uncaught-logs }
-foreground { redirfd -w 2 /dev/null mkdir -p ${1}/.s6-svscan ${1}/s6-svscan-log }
-foreground { redirfd -w 2 /dev/null ln -sf /bin/false ${1}/.s6-svscan/crash }
+
+
+# Copy all the early services and link them into the scandir
+
+if { /bin/cp -a /etc/s6/early-services /run/services }
 if
 {
-  redirfd -w 1 ${1}/.s6-svscan/finish
-  heredoc 0 "#!/bin/execlineb -P\ns6-svc -X -- \"${1}/s6-svscan-log\"\n"
-  cat
+  forbacktickx -pnd"\n" i { ls -1 -U /run/services }
+    importas -u i i
+    ln -nsf ../services/$i /run/service/$i
 }
-if { chmod 0755 ${1}/.s6-svscan/finish }
-foreground { redirfd -w 2 /dev/null mkfifo -m 0600 ${1}/s6-svscan-log/fifo }
+
+
+# Create the catch-all logger servicedir directly in the scandir
+# (It's too fundamental to be made configurable as an early service.)
+
+if { rm -f /run/service/s6-svscan-log/fifo }
+if { mkfifo -m 0600 /run/service/s6-svscan-log/fifo }
 if
 {
-  redirfd -w 1 ${1}/s6-svscan-log/run
+  redirfd -w 1 /run/service/s6-svscan-log/run
   heredoc 0 "#!/bin/execlineb -P
 redirfd -w 2 /dev/console
 redirfd -rnb 0 fifo
@@ -24,9 +56,13 @@ exec -c
 s6-log t /run/uncaught-logs\n"
   cat
 }
-if { chmod 0755 ${1}/s6-svscan-log/run }
+if { chmod 0755 /run/service/s6-svscan-log/run }
+
+
+# All ready, exec into s6-svscan.
+# By default all messages from all services will go to the catch-all logger it spawns.
 
 redirfd -r 0 /dev/null
-redirfd -wnb 1 ${1}/s6-svscan-log/fifo
+redirfd -wnb 1 /run/service/s6-svscan-log/fifo
 fdmove -c 2 1
-s6-svscan -St0 ${1}
+s6-svscan -St0 /run/service
diff --git a/system/s6/s6.initd b/system/s6/s6.initd
deleted file mode 100644
index 9f984cc13..000000000
--- a/system/s6/s6.initd
+++ /dev/null
@@ -1,15 +0,0 @@
-#!/sbin/openrc-run
-# Copyright 2016 Laurent Bercot
-# Distributed under the terms of the ISC License.
-#
-# We currently start the supervision tree under OpenRC because
-# it's easy integration. It's not perfect: the supervision tree
-# should ideally be rooted in process 1, and here it's not.
-# But it's only temporary: in a later Alpine release, s6-svscan
-# will *be* process 1.
-
-name="s6"
-command="/lib/s6/s6-svscanboot"
-command_args="/run/service"
-pidfile="/run/s6.pid"
-start_stop_daemon_args="-b -m -k 022"
diff --git a/system/s6/s6.post-upgrade b/system/s6/s6.post-upgrade
new file mode 100644
index 000000000..54144895b
--- /dev/null
+++ b/system/s6/s6.post-upgrade
@@ -0,0 +1,3 @@
+#!/bin/sh -e
+
+rm -f /etc/runlevels/default/s6
diff --git a/system/s6/s6.pre-install b/system/s6/s6.pre-install
index 19804af6d..2c175a325 100644
--- a/system/s6/s6.pre-install
+++ b/system/s6/s6.pre-install
@@ -2,5 +2,5 @@
 
 addgroup -S catchlog 2>/dev/null
 adduser -S -D -H -s /bin/false -G catchlog -g catchlog catchlog 2>/dev/null
-echo 'Run "rc-update add s6 default" to automatically start a s6 supervision tree on /run/service at boot time.' 1>&2
+
 exit 0
diff --git a/system/s6/s6.pre-upgrade b/system/s6/s6.pre-upgrade
index 19804af6d..2c175a325 100644
--- a/system/s6/s6.pre-upgrade
+++ b/system/s6/s6.pre-upgrade
@@ -2,5 +2,5 @@
 
 addgroup -S catchlog 2>/dev/null
 adduser -S -D -H -s /bin/false -G catchlog -g catchlog catchlog 2>/dev/null
-echo 'Run "rc-update add s6 default" to automatically start a s6 supervision tree on /run/service at boot time.' 1>&2
+
 exit 0