#!/bin/sh
#
#   Resource Agent for managing dhcpd resources.
#
#   License:      GNU General Public License (GPL)
#   (c) 2011-2012 Chris Bowlby,
#
# A fair amount of this script has been pulled from the official 0dhcpd 
# init script. Those portions have been integrated into this script to
# ensure consistent behavior between the resource agent and the
# original script. The copyrights and original authors are credited
# as follows:
#
# Copyright (c) 1996, 1997, 1998 S.u.S.E. GmbH
# Copyright (c) 1998, 1999, 2000, 2001 SuSE GmbH
# Copyright (c) 2002, 2003 SuSE Linux AG
# Copyright (c) 2004-2008 SUSE LINUX Products GmbH, Nuernberg, Germany.
#
# Author(s) : Rolf Haberrecker <rolf@suse.de>, 1997-1999
#             Peter Poeml <poeml@suse.de>, 2000-2006
#             Marius Tomaschewski <mt@suse.de>, 2006-2010
#
#                 and Linux-HA contributors

# Initialization:
: ${OCF_FUNCTIONS_DIR=${OCF_ROOT}/lib/heartbeat}
. ${OCF_FUNCTIONS_DIR}/ocf-shellfuncs

# Defaults
OCF_RESKEY_binary_default="dhcpd"
OCF_RESKEY_pid_default="/var/run/dhcpd.pid"
OCF_RESKEY_user_default=dhcpd
OCF_RESKEY_group_default=nogroup
OCF_RESKEY_config_default=""
OCF_RESKEY_chrooted_default="true"
OCF_RESKEY_chrooted_path_default="/var/lib/dhcp"
OCF_RESKEY_leases_default="/db/dhcpd.leases"
OCF_RESKEY_interface_default=""
OCF_RESKEY_includes_default=""

# On some systems, the chrooted default is slightly different.
# Lets do our best to support both by default.
if [ ! -d "$OCF_RESKEY_chrooted_path_default" ]; then
	if [ -d "/var/lib/dhcpd" ]; then
		OCF_RESKEY_chrooted_path_default="/var/lib/dhcpd"
	fi
fi

: ${OCF_RESKEY_binary=${OCF_RESKEY_binary_default}}
: ${OCF_RESKEY_pid=${OCF_RESKEY_pid_default}}
: ${OCF_RESKEY_user=${OCF_RESKEY_user_default}}
: ${OCF_RESKEY_group=${OCF_RESKEY_group_default}}
: ${OCF_RESKEY_chrooted=${OCF_RESKEY_chrooted_default}}
: ${OCF_RESKEY_chrooted_path=${OCF_RESKEY_chrooted_path_default}}
: ${OCF_RESKEY_config=${OCF_RESKEY_config_default}}
: ${OCF_RESKEY_leases=${OCF_RESKEY_leases_default}}
: ${OCF_RESKEY_interface=${OCF_RESKEY_interface_default}}
: ${OCF_RESKEY_includes=${OCF_RESKEY_includes_default}}

# To enable support for different versions of dhcp, we need
# to know what version we are being run against.
DHCP_VERSION_MAJOR=`$OCF_RESKEY_binary --version 2>&1 | awk -F- '{print $3}' | awk -F.  '{print $1}' | sed s/^[a-zA-Z]//g`

# These files are always copied by default to ensure the chroot environment works.
DEFAULT_FILE_LIST="/etc/gai.conf /etc/nsswitch.conf /etc/resolv.conf /etc/host.conf /etc/hosts /etc/localtime /dev/urandom"

usage() {
    cat <<EOF
        usage: $0 start|stop|monitor|meta-data|validate-all

        $0 manages the dhcp (dhcpd) server as an HA resource.

        The 'start' operation starts the dhcpd server.
        The 'stop' operation stops the dhcpd server.
        The 'restart' operation restarts the dhcpd server.
        The 'monitor' operation reports whether the dhcpd service is running.
        The 'validate-all' operation reports whether the parameters are valid.
EOF
  return $OCF_SUCCESS
}

dhcpd_meta_data()  {
        cat <<EOF
<?xml version="1.0"?>
<!DOCTYPE resource-agent SYSTEM "ra-api-1.dtd">
<resource-agent name="dhcpd" version="0.1">
  <version>1.0</version>
  <longdesc lang="en">
Manage an ISC DHCP server service in a chroot environment.
  </longdesc>
  <shortdesc lang="en">Chrooted ISC DHCP server resource agent.</shortdesc>
  <parameters>
    <parameter name="config" unique="1" required="1">
      <longdesc lang="en">
	The absolute path to the DHCP server configuration file.
      </longdesc>
      <shortdesc lang="en">Configuration file</shortdesc>
      <content type="string" default="$OCF_RESKEY_config_default"/>
    </parameter>
    <parameter name="chrooted" unique="1" required="0">
      <longdesc lang="en">
	Configure the dhcpd service to run in a chrooted or non-chrooted
	mode.
      </longdesc>
      <shortdesc lang="en">Enable chroot mode</shortdesc>
      <content type="boolean" default="$OCF_RESKEY_chrooted_default"/>
    </parameter>
    <parameter name="chrooted_path" unique="1" required="0">
      <longdesc lang="en">
	The absolute path of the chrooted DHCP environment.
      </longdesc>
      <shortdesc lang="en">The chrooted path</shortdesc>
      <content type="string" default="$OCF_RESKEY_chrooted_path_default"/>
    </parameter>
    <parameter name="binary" unique="0" required="0">
      <longdesc lang="en">
	The binary for the DHCP server process. An absolute path
	definition is not required, but can be used to override
	environment path.
      </longdesc>
      <shortdesc lang="en">dhcpd binary</shortdesc>
      <content type="string" default="$OCF_RESKEY_binary_default"/>
    </parameter>
    <parameter name="user" unique="0" required="0">
      <longdesc lang="en">
	The system user the DHCP server process will run as when
	it is chrooted.
      </longdesc>
      <shortdesc lang="en">dhcpd owner</shortdesc>
      <content type="string" default="$OCF_RESKEY_user_default"/>
    </parameter>
    <parameter name="group" unique="0" required="0">
      <longdesc lang="en">
	The system group the DHCP server process will run as when
	it is chrooted.
      </longdesc>
      <shortdesc lang="en">dhcpd group owner</shortdesc>
      <content type="string" default="$OCF_RESKEY_group_default"/>
    </parameter>
    <parameter name="interface" unique="0" required="0">
      <longdesc lang="en">
	The network interface(s) the DHCP server process will
	bind to. A blank value will bind the process to all
	interfaces.
      </longdesc>
      <shortdesc lang="en">Network Interface</shortdesc>
      <content type="string" default="$OCF_RESKEY_interface_default"/>
    </parameter>
    <parameter name="includes" unique="0" required="0">
      <longdesc lang="en">
	This parameter provides a means to copy include files
	into the chrooted environment. If a dhcpd.conf file
	contains a line similar to this:

		include "/etc/named.keys";

	Then an admin also has to tell the dhcpd RA that this
	file should be pulled into the chrooted environment. This
	is a space delimited list.
      </longdesc>
      <shortdesc lang="en">Include files</shortdesc>
      <content type="string" default="$OCF_RESKEY_includes_default"/>
    </parameter>
    <parameter name="leases" unique="0" required="0">
      <longdesc lang="en">
	The leases database file, relative to chrooted_path.
      </longdesc>
      <shortdesc lang="en">Leases file</shortdesc>
      <content type="string" default="$OCF_RESKEY_leases_default"/>
    </parameter>
    <parameter name="pid" unique="0" required="0">
      <longdesc lang="en">
	The path and filename of the PID file. It is relative
	to chrooted_path.
      </longdesc>
      <shortdesc lang="en">PID file</shortdesc>
      <content type="string" default="$OCF_RESKEY_pid_default"/>
    </parameter>
  </parameters>
  <actions>
    <action name="start"        timeout="20s" />
    <action name="stop"         timeout="20s" />
    <action name="restart"         timeout="20s" />
    <action name="monitor"      timeout="20s" interval="10s" depth="0" />
    <action name="meta-data"    timeout="5s" />
    <action name="validate-all"   timeout="20s" />
  </actions>
</resource-agent>
EOF
}

# Validate most critical parameters
dhcpd_validate_all() {
    check_binary $OCF_RESKEY_binary


    if ! ocf_is_probe; then
	# Test for the appropriate configuration files depending on if
	# chroot mode is enabled.
	if ocf_is_true $OCF_RESKEY_chrooted ; then
	    if ! test -e "$OCF_RESKEY_chrooted_path"; then
		ocf_exit_reason "Path $OCF_RESKEY_chrooted_path does not exist."
		return $OCF_ERR_INSTALLED
	    fi

	    if test -n "$OCF_RESKEY_chrooted_path/$OCF_RESKEY_config" -a ! -r "$OCF_RESKEY_chrooted_path/$OCF_RESKEY_config"; then
		ocf_exit_reason "Configuration file $OCF_RESKEY_chrooted_path/$OCF_RESKEY_config doesn't exist"
		return $OCF_ERR_INSTALLED
	    fi
	else
	    if test -n "$OCF_RESKEY_config" -a ! -r "$OCF_RESKEY_config"; then
		ocf_exit_reason "Configuration file $OCF_RESKEY_config doesn't exist"
		return $OCF_ERR_INSTALLED
	    fi
	fi

    fi 

    if ! getent passwd $OCF_RESKEY_user >/dev/null 2>&1; then
        ocf_exit_reason "User $OCF_RESKEY_user doesn't exist"
        return $OCF_ERR_INSTALLED
    fi

    return $OCF_SUCCESS
}

# dhcpd_monitor. Send a request to dhcpd and check response.
dhcpd_monitor() {
    # Assume chrooted mode is being used, but if not update the PIDF
    # variable to point to the non-chrooted PID file.
    PIDF="$OCF_RESKEY_chrooted_path/$OCF_RESKEY_pid"

    if ! ocf_is_true $OCF_RESKEY_chrooted ; then
	PIDF=`dirname $OCF_RESKEY_pid`/dhcpd/`basename $OCF_RESKEY_pid`
    fi

    ocf_pidfile_status $PIDF >/dev/null 2>&1 || return $OCF_NOT_RUNNING

    return $OCF_SUCCESS
}

# Initialize Chroot
dhcpd_initialize_chroot() {
    # If we are running the initialization for the first time, we need to make
    # the new chrooted folder, in case we are not using the same default.
    if ! [ -d $OCF_RESKEY_chrooted_path ] ; then
	ocf_log info "Initializing $OCF_RESKEY_chrooted_path for use."
    fi

    # Make sure all sub-paths are created if something went wrong during
    # a partial run.
    for i in db dev etc lib64 var/run; do
	mkdir -p $OCF_RESKEY_chrooted_path/$i
    done

    # If we are running version 4 of the dhcp server, we need to mount a proc partition.
    if [ $DHCP_VERSION_MAJOR -ge 4 ] ; then
	mkdir -p $OCF_RESKEY_chrooted_path/proc

	if ! [ -e $OCF_RESKEY_chrooted_path/proc/net/dev ] ; then
	    mount -t proc -o ro proc $OCF_RESKEY_chrooted_path/proc > /dev/null 2>&1
	fi
    fi

    # If the folder to store the PID file does not exist, make it.
    if ! [ -d "$OCF_RESKEY_chrooted_path`dirname $OCF_RESKEY_pid`" ] ; then
	mkdir -p "$OCF_RESKEY_chrooted_path`dirname $OCF_RESKEY_pid`"
    fi

    # Ensure all permissions are in place if the folder was re-created.
    chown -R $OCF_RESKEY_user:$OCF_RESKEY_group $OCF_RESKEY_chrooted_path/`dirname $OCF_RESKEY_leases`
    chown -R $OCF_RESKEY_user:$OCF_RESKEY_group "$OCF_RESKEY_chrooted_path/`dirname $OCF_RESKEY_pid`"

    ## If there is no conf file, we can't initialize the chrooted 
    ## environment, return with "program not configured"
    if ! [ -f $OCF_RESKEY_config ] ; then
	ocf_exit_reason "dhcpd has not been configured."
	return $OCF_ERR_CONFIGURED
    fi

    # If the leases file does not exist, create it, as this is a fresh install.
    if [ ! -e $OCF_RESKEY_chrooted_path/$OCF_RESKEY_leases ]; then
	touch $OCF_RESKEY_chrooted_path/$OCF_RESKEY_leases
    fi

    # Remove the random device.
    test -e "$OCF_RESKEY_chrooted_path/dev/urandom" &&
	rm -f $OCF_RESKEY_chrooted_path/dev/urandom

    # Test for the existance of the defined include files, and append
    # them to the list of files to be copied.
    for i in $OCF_RESKEY_includes ; do
	if [ -e $i ] ; then
	    DEFAULT_FILE_LIST="$DEFAULT_FILE_LIST $i"
	else
	    ocf_exit_reason "include file $i does not exist"
	    return $OCF_ERR_INSTALLED
	fi
    done

    # Ensure all "modified" non-chrooted configuration files are copied into the chrooted environment.
    for i in $OCF_RESKEY_config $DEFAULT_FILE_LIST; do
	# First, lets make sure the directory exists within the chrooted environment.
	if test -d "$i" ; then
	    mkdir -p $OCF_RESKEY_chrooted_path/$i
	elif test -e "$i" ; then
	    mkdir -p "`dirname $OCF_RESKEY_chrooted_path/$i`"
	fi

	# Next, we copy the configuration file into place.
	cp -aL "$i" "$OCF_RESKEY_chrooted_path/${i%/*}/" > /dev/null 2>&1 ||
	    { ocf_exit_reason "could not copy $i to chroot jail"; return $OCF_ERR_GENERIC; }
    done

    libdir=$(basename $(echo ${OCF_RESKEY_chrooted_path}/lib*))
    if test -x /usr/bin/ldd ; then
	get_ldd_deps()
	{
	    ldd_wl="/$libdir/lib"
	    ldd_bl="/$libdir/libc\."
	    /usr/bin/ldd "$1" | while read a b c d ; do
		[ -n "$c" ] || continue
		echo "$c" | grep -q "$ldd_wl" || continue
		echo "$c" | grep -q "$ldd_bl" && continue
		echo $c
	    done
	}
    else
	get_ldd_deps() { :; }
    fi
    cplibs=`for i in /$libdir/libresolv.so.* /$libdir/libnss_*.so.* /$libdir/libpthread.so.0 /$libdir/libdl.so.2
    do
	if [ -s "$i" ] ; then
	    echo "$i"
	    get_ldd_deps "$i"
	fi
    done | sort -u`
    for i in $cplibs ; do
	if [ -s "$i" ]; then
	    cp -aL "$i" "${OCF_RESKEY_chrooted_path}/$libdir/" ||
		{ ocf_exit_reason "could not copy $i to chroot jail"; return $OCF_ERR_GENERIC; }
	fi
    done

    return $OCF_SUCCESS
}

# Initialize a non-chroot environment
dhcpd_initialize() {
    ## If there is no conf file, we can't start a dhcp service.
    if ! [ -f $OCF_RESKEY_config ] ; then
	ocf_exit_reason "dhcpd has not been configured."
	return $OCF_ERR_CONFIGURED
    fi

    # As with the standard DHCP init script, we can still use the
    # chrooted default path for storing the leases file. This behavior
    # is consistent with the existing /etc/init.d/dhcpd script.
    if ! [ -d $OCF_RESKEY_chrooted_path ] ; then
	ocf_log info "Initializing $OCF_RESKEY_chrooted_path for use."
    fi
    
    # If the leases file does not exist, create it, as this is a fresh install.
    if [ ! -e $OCF_RESKEY_chrooted_path/$OCF_RESKEY_leases ]; then
	touch $OCF_RESKEY_chrooted_path/$OCF_RESKEY_leases
    fi

    # if the PID storage path does not exist, make it, and setup the permissions.

    # NOTE: This part of the script has a potential security flaw, in that if someone
    # puts in /var/run as the path, it will change ownership to the dhcpd user
    # and group. However, all that would do is allow that user to view the contents
    # of the files, which they can do now anyway. If this becomes an issue, I can work
    # in some changes.

    # We need to append "dhcpd" to the path for the PID file storage folder, because
    # if /var/run is used, that folders permissions can not be changed, otherwise it affects
    # more then just one application.
    if ! [ -d `dirname $OCF_RESKEY_pid`/dhcpd ] ; then
	mkdir -p `dirname $OCF_RESKEY_pid`/dhcpd

        if [ -n "$OCF_RESKEY_user" -a "x$OCF_RESKEY_user" != "xroot" ] ; then
	    chown $OCF_RESKEY_user `dirname $OCF_RESKEY_pid`/dhcpd
        fi
    
        if [ -n "$OCF_RESKEY_group" -a "x$OCF_RESKEY_group" != "xwheel" ] ; then
	    chgrp $OCF_RESKEY_group `dirname $OCF_RESKEY_pid`/dhcpd
        fi
    fi

    return $OCF_SUCCESS
}

# Start
dhcpd_start() {
    # Lets make sure we are not already running.
    if dhcpd_monitor; then
		ocf_log info "dhcpd already running"
		return $OCF_SUCCESS
	fi

    # Only initialize the chrooted path(s) if chroot mode is enabled.
    if ocf_is_true $OCF_RESKEY_chrooted ; then
	dhcpd_initialize_chroot ||
	    { ocf_exit_reason "Could not fully initialize the chroot environment." ; return $OCF_ERR_INSTALLED; }
    else
	dhcpd_initialize ||
	    { ocf_exit_reason "Could not fully initialize the runtime environment." ; return $OCF_ERR_INSTALLED; }
    fi

    dhcpd_validate_all || exit

    # Define an empty string variable, to ensure it exists when needed.
    DHCPD_ARGS=""

    # To ensure consistent behavior with the standard DHCPD init script, 
    # use the chrooted default path for storing a leases file, when not in
    # a chrooted enviroment.
    if ocf_is_true $OCF_RESKEY_chrooted ; then
	DHCPD_ARGS="$DHCPD_ARGS -chroot $OCF_RESKEY_chrooted_path -lf $OCF_RESKEY_leases"
    else
	DHCPD_ARGS="$DHCPD_ARGS -lf $OCF_RESKEY_chrooted_path/$OCF_RESKEY_leases"
    fi

    if [ -n "$OCF_RESKEY_user" ]; then
	DHCPD_ARGS="$DHCPD_ARGS -user $OCF_RESKEY_user"
    fi

    if [ -n "$OCF_RESKEY_group" ]; then
	DHCPD_ARGS="$DHCPD_ARGS -group $OCF_RESKEY_group"
    fi

    # If there is a pid file containing a pid, the machine might have crashed. pid files in
    # /var/run are always cleaned up at boot time, but this is not the case for the pid file in
    # the chroot jail. Therefore, an old pid file may exist. This is only a problem if it
    # incidentally contains the pid of a running process. If this process is not a 'dhcpd',
    # we remove the pid. (dhcpd itself only checks whether the pid is alive or not.)

    PIDF="$OCF_RESKEY_chrooted_path/$OCF_RESKEY_pid"

    if ocf_is_true $OCF_RESKEY_chrooted ; then
	ocf_log info "Starting dhcpd [chroot] service."
	DHCPD_ARGS="$DHCPD_ARGS -pf $OCF_RESKEY_pid"
    else
	ocf_log info "Starting dhcpd [non-chroot] service."
	PIDF=`dirname $OCF_RESKEY_pid`/dhcpd/`basename $OCF_RESKEY_pid`
	DHCPD_ARGS="$DHCPD_ARGS -pf $PIDF"
    fi

    test -e "$PIDF" && rm -f $PIDF

    ocf_run $OCF_RESKEY_binary -cf $OCF_RESKEY_config $DHCPD_ARGS $OCF_RESKEY_interface ||
	return $OCF_ERR_INSTALLED

    while ! dhcpd_monitor; do
		sleep .1
		ocf_log info "waiting for dhcpd to start"
		return $OCF_SUCCESS
	done

    if ocf_is_true $OCF_RESKEY_chrooted ; then
	ocf_log info "dhcpd [chrooted] has started."
    else
	ocf_log info "dhcpd [non-chrooted] has started."
    fi

    return $OCF_SUCCESS
}

# Stop
dhcpd_stop () {
    local timeout
    local timewait
    local rc

    dhcpd_monitor
    rc=$?

    case "$rc" in
	"$OCF_SUCCESS")
	    # Currently running, and is expected behaviour.
	    ;;
	"$OCF_NOT_RUNNING")
	    # Currently not running, therefore nothing to do.
		ocf_log info "dhcpd already stopped"
	    return $OCF_SUCCESS
	    ;;
    esac

    PIDF="$OCF_RESKEY_chrooted_path/$OCF_RESKEY_pid"

    if ! ocf_is_true $OCF_RESKEY_chrooted ; then
	PIDF=`dirname $OCF_RESKEY_pid`/dhcpd/`basename $OCF_RESKEY_pid`
    fi

    kill `cat $PIDF`

    # Allow 2/3 of the action timeout for the orderly shutdown
    # (The origin unit is ms, hence the conversion)
    timewait=$((OCF_RESKEY_CRM_meta_timeout/1500))

    sleep 0.1; timeout=0 # Sleep here for .1 sec to let dhcpd finish.
    while dhcpd_monitor ; do
        if [ $timeout -ge $timewait ]; then
            break
        else
            sleep 1
            timeout=`expr $timeout + 1`
        fi
    done

    #If still up
    if dhcpd_monitor 2>&1; then
        ocf_log notice "dhcpd is still up! Trying kill -s KILL"

	kill -s SIGKILL `cat $PIDF`
    fi

    # If we are running a dhcp server v4 or higher, unmount the proc partition.
    if [ $DHCP_VERSION_MAJOR -ge 4 ] ; then
	# We only want to unmount proc in a chrooted environment, else we could
	# cause other issues.
	if ocf_is_true $OCF_RESKEY_chrooted ; then
	    umount $OCF_RESKEY_chrooted_path/proc > /dev/null 2>&1
	fi
    fi

    rm -f $PIDF

    ocf_log info "dhcpd stopped"
    return $OCF_SUCCESS
}

# Make sure meta-data and usage always succeed
case $__OCF_ACTION in
meta-data)      dhcpd_meta_data
                exit $OCF_SUCCESS
                ;;
validate-all)   dhcpd_validate_all
		exit $OCF_SUCCESS
		;;
usage|help)     dhcpd_usage
                exit $OCF_SUCCESS
                ;;
esac

# Translate each action into the appropriate function call
case $__OCF_ACTION in
start)          dhcpd_start;;
stop)           dhcpd_stop;;
restart)        dhcpd_stop
                dhcpd_start
                ;;
monitor)        dhcpd_monitor;;
*)              dhcpd_usage
                exit $OCF_ERR_UNIMPLEMENTED
                ;;
esac