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Filename : dhcpcd-run-hooks
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#!/bin/sh
# dhcpcd client configuration script 

# Handy variables and functions for our hooks to use
ifname="$interface${protocol+.}$protocol"
from=from
signature_base="# Generated by dhcpcd"
signature="$signature_base $from $ifname"
signature_base_end="# End of dhcpcd"
signature_end="$signature_base_end $from $ifname"
state_dir=/run/dhcpcd/hook-state
_detected_init=false

: ${if_up:=false}
: ${if_down:=false}
: ${syslog_debug:=false}

# Ensure that all arguments are unique
uniqify()
{
	result=
	for i do
		case " $result " in
			*" $i "*);;
			*) result="$result${result:+ }$i";;
		esac
	done
	echo "$result"
}

# List interface config files in a directory.
# If dhcpcd is running as a single instance then it will have a list of
# interfaces in the preferred order.
# Otherwise we just use what we have.
list_interfaces()
{
	ifaces=
	for i in $interface_order; do
		for x in "$1"/$i.*; do
			[ -f "$x" ] && ifaces="$ifaces${ifaces:+ }${x##*/}"
		done
	done
	for x in "$1"/*; do
		[ -f "$x" ] && ifaces="$ifaces${ifaces:+ }${x##*/}"
	done
	uniqify $ifaces
}

# Trim function
trim()
{
	var="$*"
	var=${var#"${var%%[![:space:]]*}"}
	var=${var%"${var##*[![:space:]]}"}
	if [ -z "$var" ]; then
		# So it seems our shell doesn't support wctype(3) patterns
		# Fall back to sed
		var=$(echo "$*" | sed -e 's/^[[:space:]]*//;s/[[:space:]]*$//')
	fi
	printf %s "$var"
}

# We normally use sed to extract values using a key from a list of files
# but sed may not always be available at the time.
key_get_value()
{
	key="$1"
	shift

	if command -v sed >/dev/null 2>&1; then
		sed -n "s/^$key//p" $@
	else
		for x do
			while read line; do
				case "$line" in
				"$key"*) echo "${line##$key}";;
				esac
			done < "$x"
		done
	fi
}

# We normally use sed to remove markers from a configuration file
# but sed may not always be available at the time.
remove_markers()
{
	m1="$1"
	m2="$2"
	in_marker=0

	shift; shift
	if command -v sed >/dev/null 2>&1; then
		sed "/^$m1/,/^$m2/d" $@
	else
		for x do
			while read line; do
				case "$line" in
				"$m1"*) in_marker=1;;
				"$m2"*) in_marker=0;;
				*) [ $in_marker = 0 ] && echo "$line";;
				esac
			done < "$x"
		done
	fi
}

# Compare two files.
comp_file()
{
	[ -e "$1" ] && [ -e "$2" ] || return 1

	if command -v cmp >/dev/null 2>&1; then
		cmp -s "$1" "$2"
	elif command -v diff >/dev/null 2>&1; then
		diff -q "$1" "$2" >/dev/null
	else
		# Hopefully we're only working on small text files ...
		[ "$(cat "$1")" = "$(cat "$2")" ]
	fi
}

# Compare two files.
# If different, replace first with second otherwise remove second.
change_file()
{
	if [ -e "$1" ]; then
		if comp_file "$1" "$2"; then
			rm -f "$2"
			return 1
		fi
	fi
	cat "$2" > "$1"
	rm -f "$2"
	return 0
}

# Compare two files.
# If different, copy or link depending on target type
copy_file()
{
	if [ -h "$2" ]; then
		[ "$(readlink "$2")" = "$1" ] && return 1
		ln -sf "$1" "$2"
	else
		comp_file "$1" "$2" && return 1
		cat "$1" >"$2"
	fi
}

# Save a config file
save_conf()
{
	if [ -f "$1" ]; then
		rm -f "$1-pre.$interface"
		cat "$1" > "$1-pre.$interface"
	fi
}

# Restore a config file
restore_conf()
{
	[ -f "$1-pre.$interface" ] || return 1
	cat "$1-pre.$interface" > "$1"
	rm -f "$1-pre.$interface"
}

# Write a syslog entry
syslog()
{
	lvl="$1"

	if [ "$lvl" = debug ]; then
		${syslog_debug} || return 0
	fi
	[ -n "$lvl" ] && shift
	[ -n "$*" ] || return 0
	case "$lvl" in
	err|error)	echo "$interface: $*" >&2;;
	*)		echo "$interface: $*";;
	esac
	if command -v logger >/dev/null 2>&1; then
		logger -i -p daemon."$lvl" -t dhcpcd-run-hooks "$interface: $*"
	fi
}

# Check for a valid name as per RFC952 and RFC1123 section 2.1
valid_domainname()
{
	name="$1"
	[ -z "$name" ] || [ ${#name} -gt 255 ] && return 1
	
	while [ -n "$name" ]; do
		label="${name%%.*}"
		[ -z "$label" ] || [ ${#label} -gt 63 ] && return 1
		case "$label" in
		-*|_*|*-|*_)		return 1;;
		*[![:alnum:]_-]*)	return 1;;
		"$name")		return 0;;
		esac
		name="${name#*.}"
	done
	return 0
}

valid_domainname_list()
{
	for name do
		valid_domainname "$name" || return $?
	done
	return 0
}

# With the advent of alternative init systems, it's possible to have
# more than one installed. So we need to try to guess what one we're
# using unless overridden by configure.
detect_init()
{
	_service_exists=""
	_service_cmd=""
	_service_status=""

	[ -n "$_service_cmd" ] && return 0

	if $_detected_init; then
		[ -n "$_service_cmd" ]
		return $?
	fi

	# Detect the running init system.
	# As systemd and OpenRC can be installed on top of legacy init
	# systems we try to detect them first.
	status=""
	: ${status:=status}
	if [ -x /bin/systemctl ] && [ -S /run/systemd/private ]; then
		_service_exists="/bin/systemctl --quiet is-enabled \$1.service"
		_service_status="/bin/systemctl --quiet is-active \$1.service"
		_service_cmd="/bin/systemctl \$2 --no-block \$1.service"
	elif [ -x /usr/bin/systemctl ] && [ -S /run/systemd/private ]; then
		_service_exists="/usr/bin/systemctl --quiet is-enabled \$1.service"
		_service_status="/usr/bin/systemctl --quiet is-active \$1.service"
		_service_cmd="/usr/bin/systemctl \$2 --no-block \$1.service"
	elif [ -x /sbin/rc-service ] &&
	     { [ -s /libexec/rc/init.d/softlevel ] ||
	     [ -s /run/openrc/softlevel ]; }
	then
		_service_exists="/sbin/rc-service -e \$1"
		_service_cmd="/sbin/rc-service \$1 -- -D \$2"
	elif [ -x /usr/sbin/invoke-rc.d ]; then
		_service_exists="/usr/sbin/invoke-rc.d --query --quiet \$1 start >/dev/null 2>&1 || [ \$? = 104 ]"
		_service_cmd="/usr/sbin/invoke-rc.d \$1 \$2"
	elif [ -x /sbin/service ]; then
		_service_exists="/sbin/service \$1 >/dev/null 2>&1"
		_service_cmd="/sbin/service \$1 \$2"
	elif [ -x /usr/sbin/service ]; then
		_service_exists="/usr/sbin/service \$1 $status >/dev/null 2>&1"
		_service_cmd="/usr/sbin/service \$1 \$2"
	elif [ -x /bin/sv ]; then
		_service_exists="/bin/sv status \$1 >/dev/null 2>&1"
		_service_cmd="/bin/sv \$2 \$1"
	elif [ -x /usr/bin/sv ]; then
		_service_exists="/usr/bin/sv status \$1 >/dev/null 2>&1"
		_service_cmd="/usr/bin/sv \$2 \$1"
	elif [ -e /etc/slackware-version ] && [ -d /etc/rc.d ]; then
		_service_exists="[ -x /etc/rc.d/rc.\$1 ]"
		_service_cmd="/etc/rc.d/rc.\$1 \$2"
		_service_status="/etc/rc.d/rc.\$1 status >/dev/null 2>&1"
	else
		for x in /etc/init.d/rc.d /etc/rc.d /etc/init.d; do
			if [ -d $x ]; then
				_service_exists="[ -x $x/\$1 ]"
				_service_cmd="$x/\$1 \$2"
				_service_status="$x/\$1 $status >/dev/null 2>&1"
				break
			fi
		done
		if [ -e /etc/arch-release ]; then
			_service_status="[ -e /var/run/daemons/\$1 ]"
		elif [ "$x" = "/etc/rc.d" ] && [ -e /etc/rc.d/rc.subr ]; then
			_service_status="$x/\$1 check >/dev/null 2>&1"
		fi
	fi

	_detected_init=true
	if [ -z "$_service_cmd" ]; then
		syslog err "could not detect a useable init system"
		return 1
	fi
	return 0
}

# Check a system service exists 
service_exists()
{
	if [ -z "$_service_exists" ]; then
		detect_init || return 1
	fi
	eval $_service_exists
}

# Send a command to a system service
service_cmd()
{
	if [ -z "$_service_cmd" ]; then
		detect_init || return 1
	fi
	eval $_service_cmd
}

# Send a command to a system service if it is running
service_status()
{
	if [ -z "$_service_cmd" ]; then
		detect_init || return 1
	fi
	if [ -n "$_service_status" ]; then
		eval $_service_status
	else
		service_command $1 status >/dev/null 2>&1
	fi
}

# Handy macros for our hooks
service_command()
{
	service_exists $1 && service_cmd $1 $2
}
service_condcommand()
{
	service_exists $1 && service_status $1 && service_cmd $1 $2
}

# We source each script into this one so that scripts run earlier can
# remove variables from the environment so later scripts don't see them.
# Thus, the user can create their dhcpcd.enter/exit-hook script to configure
# /etc/resolv.conf how they want and stop the system scripts ever updating it.
for hook in \
	/etc/dhcpcd.enter-hook \
	/usr/lib/dhcpcd/dhcpcd-hooks/* \
	/etc/dhcpcd.exit-hook
do
	case "$hook" in
		*/*~)	continue;;
	esac
	for skip in $skip_hooks; do
		case "$hook" in
			*/"$skip")			continue 2;;
			*/[0-9][0-9]"-$skip")		continue 2;;
			*/[0-9][0-9]"-$skip.sh")	continue 2;;
		esac
	done
	if [ -f "$hook" ]; then
		. "$hook"
	fi
done