adding example runit-style service directory

Signed-off-by: Denys Vlasenko <vda.linux@googlemail.com>

examples/var_service/dhcp_if/convert2ipconf

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+#!/bin/sh
+# convert:
+
+# dhcptype=5
+# serverid=172.16.42.102
+# lease=97200
+# interface=eth0
+# ip=172.16.42.177
+# subnet=255.255.255.0
+# mask=24
+# broadcast=172.16.22.255
+# router=172.16.42.98
+# dns=10.34.32.125 10.32.63.5 10.34.255.7 10.11.255.27
+# domain=lab.example.com example.com
+# ntpsrv=10.34.32.125 10.34.255.7
+
+# into:
+
+#let cfg=cfg+1
+#if[$cfg]=...; ip[$cfg]=...; ipmask[$cfg]=.../...; gw[$cfg]=...; net[$cfg]=... dns[$cfg]=...
+
+exec >"$0.out" 2>&1
+
+test "$interface" || exit 1
+test -f "$1" || exit 1
+
+# Unsafe, and does not handle values with spaces:
+#. "./$1" || exit 1
+# Safe(r) parsing:
+sq="'"
+while read line; do
+	#echo "line: $line"
+	# Skip empty lines and lines with single quotes
+	test "${line##*$sq*}" || continue
+	var="${line%%=*}"
+	val="${line#*=}"
+	#echo "var:$var val:'$val'"
+	eval "$var='$val'"
+done <"$1"
+
+{
+echo "let cfg=cfg+1"
+test "$interface" 	&& echo "if[\$cfg]='$interface'"
+test "$ip"		&& echo "ip[\$cfg]='$ip'"
+test "$ip" && test "$mask" \
+			&& echo "ipmask[\$cfg]='$ip/$mask'"
+test "$router"		&& echo "gw[\$cfg]='$router'"
+test "$dns"		&& echo "dns[\$cfg]='$dns'"
+# TODO: I never saw a dhcp server which correctly announces
+# which subnet(s) is/are available thru advertised router
+# Assume 0/0
+echo "net[\$cfg]='0/0'"
+} >"$2"

examples/var_service/dhcp_if/dhcp_handler

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+#!/bin/sh
+# executed by udhcpc
+# parameters: $1 and environment
+#
+# $1 is:
+#
+# deconfig: This argument is used when udhcpc starts, and
+# when a lease is lost. The script should put the interface in an
+# up, but deconfigured state, ie: ifconfig $interface 0.0.0.0.
+# Environment: interface=ethN
+#
+# bound: This argument is used when udhcpc moves from an
+# unbound, to a bound state. All of the paramaters are set in
+# enviromental variables, The script should configure the interface,
+# and set any other relavent parameters (default gateway, dns server, etc).
+# Environment:
+# dhcptype=5
+# serverid=172.16.42.102
+# lease=97200
+# interface=eth0
+# ip=172.16.42.177
+# subnet=255.255.255.0
+# mask=24
+# broadcast=172.16.22.255
+# router=172.16.42.98
+# dns=10.34.32.125 10.32.63.5 10.34.255.7 10.11.255.27
+# domain=lab.example.com example.com
+# ntpsrv=10.34.32.125 10.34.255.7
+#
+# renew: This argument is used when a DHCP lease is renewed. All of
+# the paramaters are set in enviromental variables. This argument is
+# used when the interface is already configured, so the IP address,
+# will not change, however, the other DHCP paramaters, such as the
+# default gateway, subnet mask, and dns server may change.
+# Environment: same as for "bound".
+#
+# nak: This argument is used with udhcpc receives a NAK message.
+# The script with the deconfig argument will be called directly
+# afterwards, so no changes to the network interface are neccessary.
+# This hook is provided for purely informational purposes (the
+# message option may contain a reason for the NAK).
+# Environment: interface=ethN, serverid=IP_ADDR
+#
+# leasefail: called when lease cannot be obtained
+# (for example, when DHCP server is down).
+# Environment: interface=ethN
+
+# TODO: put domain into /etc/resolv.conf (thru /var/service/fw)
+# TODO: feed ntp IPs to /var/service/ntp
+
+service=`basename $PWD`
+outfile="$service.ipconf"
+dir="/var/run/service/fw"
+
+exec >>"$0.out" 2>&1
+
+echo "`date`: Params: $*"
+
+if test x"$1" != x"bound" && test x"$1" != x"renew" ; then
+	# Reconfigure network with this interface disabled
+	echo "Deconfiguring"
+	rm "$service.out"
+	rm "$outfile"
+	rm "$dir/$outfile"
+	sv u /var/service/fw
+	exit
+fi
+
+# Bound: we've got the lease
+
+# Process params
+env >"$service.out"
+./convert2ipconf "$service.out" "$outfile"
+
+# Reconfigure routing and firewall if needed
+diff --brief "$outfile" "$dir/$outfile" >/dev/null 2>&1
+if test "$?" != "0"; then
+	echo "Reconfiguring"
+	mkdir -p "$dir" 2>/dev/null
+	cp "$outfile" "$dir/$outfile"
+	sv u /var/service/fw
+fi

examples/var_service/dhcp_if/log/run

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+#!/bin/sh
+
+user=logger
+
+logdir="/var/log/service/`(cd ..;basename $PWD)`"
+mkdir -p "$logdir" 2>/dev/null
+chown -R "$user": "$logdir"
+chmod -R go-rwxst,u+rwX "$logdir"
+rm logdir
+ln -s "$logdir" logdir
+
+# make this dir accessible to logger
+chmod a+rX .
+
+exec >/dev/null
+exec 2>&1
+exec \
+env - PATH="$PATH" \
+softlimit \
+setuidgid "$user" \
+svlogd -tt "$logdir"

examples/var_service/dhcp_if/p_log

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+#!/bin/sh
+
+cd log/logdir || exit 1
+cat @* current | $PAGER

examples/var_service/dhcp_if/run

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+#!/bin/sh
+
+exec 2>&1
+exec </dev/null
+
+pwd="$PWD"
+
+if="${PWD##*/dhcp_}"
+
+echo "* Upping iface $if"
+ip link set dev "$if" up
+
+echo "* Starting udhcpc"
+exec \
+env - PATH="$PATH" \
+softlimit \
+setuidgid root \
+udhcpc -vv \
+--hostname=null \
+--foreground \
+--interface="$if" \
+--pidfile="$pwd/udhcpc.pid" \
+--script="$pwd/dhcp_handler"

examples/var_service/dhcp_if/w_log

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+#!/bin/sh
+
+cd log/logdir || exit 1
+watch -n2 'w=`ttysize w`; h=`ttysize h`; tail -$((h-3)) current 2>&1 | cut -b0-$((w-2))'