init system (which on most main distributions is now Systemd, Sys V init, or
OpenRC).
+Be warned that it is not a trivial task to take a system based on a typical
+Linux distribution and make it instead boot with Dinit. You need to set up
+suitable service description files for your system; at present there are no
+automated conversion tools for converting service descriptions or startup
+scripts from other systems.
+
The additional software required can be broken into _essential_ and
_optional_ packages, which are detailed in following sections. For example service
files, please check the "services" subdirectory.
interfaces
- /dev/shm - tmpfs - used for shared memory
- /dev/pts - devpts - pseudoterminal devices
-- /run - tmpfs - storage for program state; used by udev
+- /run - tmpfs - storage for program state (replacement for /var/run); used by
+ udev and some other programs
These filesystems (particularly /sys, /proc and /run) need to be mounted
quite early as they will be used by early-boot processes.
for your particular configuration.
-# Essential packages
+# Boot performance compared to Systemd
+
+Boot performance using Dinit suffers slightly compared to Systemd due to
+several factors:
+
+- Dinit doesn't handle file system mounts/checks and spawns external
+ processes and/or scripts to manage these
+- In the absence of full udev integration, it is more difficult to start
+ some services as early as possible. For instance, filesystem mounts need
+ to wait for the appropriate device to be recognized by the kernel and
+ exported as a device node; similarly network interfaces need to be
+ recognized before they are configured. With Dinit, the simplest approach
+ is to wait until udev "settles" (via "udevadm settle") before attempting
+ mounts and network configuration etc.
+- Dinit doesn't do socket activation (yet). What it can do is pre-open a
+ socket while it launches a daemon, which probably improves boot times a
+ little but potentially still results in more daemons getting started than
+ is strictly necessary.
+
+In the future Dinit might provide functionality to perform basic mounts
+without spawning an external process, and will almost certainly support full
+socket activation. Some of the more fundamental startup script functionality
+might also be offered via some kind of intrinsic service(s). However, where
+at all possible, the intention is to keep service functionality separate to
+Dinit itself.
+
+
+# Essential packages for building a Dinit-based system
+
+Other than the obvious system C library and C++ library, you'll need a range
+of packages to create a functional Dinit-based system.
First, a device node manager. I recommend "Eudev".
- Eudev - the Gentoo fork of Udev; https://github.com/gentoo/eudev
- Vdev - "a device file manager and filesystem" and a "work in progress";
https://github.com/jcnelson/vdev
-- Mdev may also be an option; it is part of the "busybox" utility suite.
+- Mdev may also be an option; it is part of the "busybox" utility suite. I
+ don't personally have any experience with it.
Then, a "getty" and "login" program. Both can be found in the util-linux
package, at: https://www.kernel.org/pub/linux/utils/util-linux
+Also provided in the util-linux package are standard utilities such as fsck
+and mount. You'll probably want e2fsprogs (or the equivalent for your chosen
+filesystem): http://e2fsprogs.sourceforge.net/
+
+The syslog daemon from GNU Inetutils is basic, but functional - which makes
+it a good fit for a Dinit-based system. https://www.gnu.org/software/inetutils
+
+You will need a shell script interpreter / command line, for which you have
+a range of options. A common choice is GNU Bash, but many distributions are
+using Dash as the /bin/sh shell because it is significantly faster (affecting
+boot time).
-# Optional packages
+- Bash: https://www.gnu.org/software/bash
+= Dash: http://gondor.apana.org.au/~herbert/dash
+
+
+# Optional packages for building a Dinit-based system
ConsoleKit2, to act as seat/sesion manager (functionality otherwise
provided by Systemd):
ConsoleKit2, and maybe if you want to use containers:
https://github.com/lxc/cgmanager
-However, I believe that cgmanage works with the old (v1) cgroups interface.
+(However, I believe that cgmanage works with the old v1 cgroups interface.
I expect that v2 cgroups together with cgroup namespaces as found in newer
-kernels will render it obselete.
+kernels will render it obselete).
+
+Both ConsoleKit2 and cgmanager use Dbus:
+https://dbus.freedesktop.org/
umask 0077
if [ "$1" != "stop" ]; then
-
- # Get system time from hardware clock
- /sbin/hwclock --adjust
- /sbin/hwclock --hctosys
# cleanup
# (delete /tmp etc)
+ rm -rf /tmp/* /tmp/.[^.]* /tmp/..?*
+ rm -rf /var/lock/* /var/lock/.[^.]* /var/lock/..?*
+ rm -rf /var/run/* /var/run/.[^.]* /var/run/..?*
+ # Create (empty) utmp database
: > /var/run/utmp
- rm -f -r /tmp/*
- rm -f -r /tmp/.[^.]*
- rm -f -r /tmp/..?*
- rm -f /var/locks/*
- rm -f -r /var/run/dbus/*
+ mkdir /var/run/dbus
# Configure random number generator
cat /var/state/random-seed > /dev/urandom
# You can put other static configuration here:
#/sbin/ifconfig eth0 192.168.1.38 netmask 255.255.255.0 broadcast 192.168.1.255
- /bin/hostname myhost
+ echo "myhost" > /proc/sys/kernel/hostname
- # networking daemons
- /usr/libexec/syslogd
- /usr/sbin/sshd
- /usr/libexec/inetd
-
# /usr/sbin/alsactl restore
- # Prevent spurious messages from kernel to console
- # (syslog will still catch them). Default in 2.4.18 is "7 4 1 7".
- # in particular this prevents "unknown scancode" messages from unrecognized
- # keys on funky keyboards, and module loading messages.
- echo "3 4 1 7" > /proc/sys/kernel/printk
-
- # Printing
- #/etc/init.d/hplip start
- /etc/init.d/cups start
-
else
# The system is being shut down
- # kill some stuff
- #if [ -e /var/run/gpm.pid ]; then kill `cat /var/run/gpm.pid`; fi
-
- /etc/init.d/cups stop
# echo "Saving random number seed..."
- dd if=/dev/urandom of=/var/state/random-seed bs=512 count=1 2> /dev/null
+ POOLSIZE=`cat /proc/sys/kernel/random/poolsize`
+ dd if=/dev/urandom of=/var/state/random-seed bs="$POOLSIZE" count=1 2> /dev/null
fi;
projects / oweals / dinit.git / commitdiff