#!/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=/var/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 \
       /libexec/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