finit/system/10-hotplug.conf.in

# System hotplug handled by udev, mdevd, or mdev (preferred order)
#
# Your system usually has either udevd, mdev, or mdevd.  They probe the system
# for devices, loading modules and any firmware needed.  Since the bootstrap
# often needs to be synchronized carefully, we suggest using your system log
# daemon as the barrier for all other services.  E.g.:
#
#    service syslogd {
#        description = "System log daemon"
#        runlevel    = "S0123456789"
#        if          = "udevd"
#        conditions  = { "run/udevadm:5/success" }
#        command     = "syslogd -F"
#    }
#
# with `if = "mdev"` or `if = "mdevd"` and the matching coldplug condition
# for those variants.
#
# This provdes a <pid/syslogd> condition that can act as a barrier for all
# other services.  Notice the `if` setting: the condition for starting
# syslogd is only considered if either udevd or mdev (service) is loaded and
# is guaranteed to run after each respective run stanza have completed.
#
# Override this file by copying it to /etc/finit.d/, using the same name, then
# change the contents any way you like, it can even be empty.
#
# The leading '-' on every command says a missing binary is expected here, so
# the block is skipped quietly and the next candidate gets its turn.

# Check for systemd-udevd and eudev, if we find both, we opt for the latter.
service udevd {
	description    = "Device event daemon (udev)"
	runlevel       = "S12345789"
	notify         = "none"
	envfile        = "-/etc/default/udevd"
	pidfile        = "udevd"
	pidfile-create = true
	log { }
	cgroup system { name = "udevd" }
	command        = "-/lib/systemd/systemd-udevd $UDEVD_ARGS"
}
service udevd {
	description    = "Device event daemon (udev)"
	runlevel       = "S12345789"
	notify         = "none"
	envfile        = "-/etc/default/udevd"
	pidfile        = "udevd"
	pidfile-create = true
	log { }
	cgroup system { name = "udevd" }
	command        = "-udevd $UDEVD_ARGS"
}

# Wait for udevd to start, then trigger coldplug events and module loading.
# The last 'settle' call waits for it to finalize processing all uevents.
run udevadm:1 {
	runlevel   = "S"
	if         = "udevd"
	conditions = { "service/udevd/ready" }
	log { }
	cgroup init { name = "udevadm" }
	command    = "-udevadm settle -t 0"
}
run udevadm:2 {
	runlevel   = "S"
	if         = "udevd"
	conditions = { "service/udevd/ready" }
	log { }
	cgroup init { name = "udevadm" }
	command    = "-udevadm control --reload"
}
run udevadm:3 {
	description = "Requesting device events"
	runlevel    = "S"
	if          = "udevd"
	conditions  = { "service/udevd/ready" }
	log { }
	cgroup init { name = "udevadm" }
	command     = "-udevadm trigger -c add -t devices"
}
run udevadm:4 {
	description = "Requesting subsystem events"
	runlevel    = "S"
	if          = "udevd"
	conditions  = { "service/udevd/ready" }
	log { }
	cgroup init { name = "udevadm" }
	command     = "-udevadm trigger -c add -t subsystems"
}
run udevadm:5 {
	description = "Waiting for udev to finish"
	runlevel    = "S"
	if          = "udevd"
	conditions  = { "service/udevd/ready" }
	log { }
	cgroup init { name = "udevadm" }
	command     = "-udevadm settle -t 30"
}

# If udevd is not available, check for mdevd.  Unlike plain 'mdev -df', the
# mdevd-coldplug process exits when mdevd has completed.  So the condition
# <run/mdevd-coldplug/success> can be relied on as a barrier for services
# that, e.g., need to probe for switchcore ports or PHYs that require
# firmware loading before they show up.
service mdevd {
	description = "Device event daemon (mdevd)"
	runlevel    = "S12345789"
	if          = "!udevd"
	conflicts   = { "udevd", "mdev" }
	notify      = "s6"
	cgroup init { name = "mdevd" }
	command     = "-mdevd -O 4 -D %n"
}

# NOTE: this block is named for its command, so its barrier condition is
#       <run/mdevd-coldplug/success>, not the <run/coldplug/success> the
#       plain mdev stanza below provides.  The legacy line spelled the
#       name inside the cgroup argument, where it names the cgroup leaf
#       rather than the service, and the two paths have differed ever
#       since.  Left as it was so boot ordering does not change.
run mdevd-coldplug {
	description = "Cold plugging system"
	runlevel    = "S"
	conflicts   = { "udevd", "mdev" }
	conditions  = { "service/mdevd/ready" }
	cgroup init { name = "coldplug" }
	command     = "-mdevd-coldplug"
}

# If neither udevd or mdevd are available, fall back to mdev.  The new daemon
# mode calls `mdev -s` internally but does not create a PID file when that is
# done, so synchronization with coldplug is fragile.
service mdev {
	description = "Device event daemon (mdev)"
	runlevel    = "S12345789"
	if          = "!udevd,!mdevd"
	conflicts   = { "udevd", "mdevd" }
	notify      = "none"
	cgroup init { name = "mdev" }
	command     = "-mdev -df -S"
}

# Trigger a replay of all uevents from boot, before userspace was up and the
# filesystem mounted.  Compared to udevd, we don't know when 'mdev -df' has
# finished processing all events, i.e., depending on <run/coldplug/success> is
# not an indicator of all devices having been (re)discovered and fully set up.
run coldplug {
	description = "Cold plugging system"
	runlevel    = "S"
	if          = "mdev"
	conflicts   = { "udevd", "mdevd" }
	conditions  = { "service/mdev/running" }
	cgroup init {}
	command     = "-@pkglibexecdir@/coldplug"
}