# This is a script with common functions etc used by zfs-import, zfs-mount,
# zfs-share and zfs-zed.
#
# It is _NOT_ to be called independently
#
# Released under the 2-clause BSD license.
#
# The original script that acted as a template for this script came from
# the Debian GNU/Linux kFreeBSD ZFS packages (which did not include a
# licensing stansa) in the commit dated Mar 24, 2011:
#   https://github.com/zfsonlinux/pkg-zfs/commit/80a3ae582b59c0250d7912ba794dca9e669e605a

PATH=/sbin:/bin:/usr/bin:/usr/sbin

# Source function library
if [ -f /etc/rc.d/init.d/functions ]; then
	# RedHat and derivates
	. /etc/rc.d/init.d/functions
elif [ -L /etc/init.d/functions.sh ]; then
	# Gentoo
	. /etc/init.d/functions.sh
elif [ -f /lib/lsb/init-functions ]; then
	# LSB, Debian GNU/Linux and derivates
	. /lib/lsb/init-functions
fi

# Of course the functions we need are called differently
# on different distributions - it would be way too easy
# otherwise!!
if type log_failure_msg > /dev/null 2>&1 ; then
	# LSB functions - fall through
	zfs_log_begin_msg() { log_begin_msg "$1"; }
	zfs_log_end_msg() { log_end_msg "$1"; }
	zfs_log_failure_msg() { log_failure_msg "$1"; }
	zfs_log_progress_msg() { log_progress_msg "$1"; }
elif type success > /dev/null 2>&1 ; then
	# Fedora/RedHat functions
	zfs_set_ifs() {
		# For some reason, the init function library have a problem
		# with a changed IFS, so this function goes around that.
		local tIFS="$1"
		if [ -n "$tIFS" ]
		then
			TMP_IFS="$IFS"
			IFS="$tIFS"
		fi
	}

	zfs_log_begin_msg() { echo -n "$1 "; }
	zfs_log_end_msg() {
		zfs_set_ifs "$OLD_IFS"
		if [ "$1" -eq 0 ]; then
			success
		else
			failure
		fi
		echo
		zfs_set_ifs "$TMP_IFS"
	}
	zfs_log_failure_msg() {
		zfs_set_ifs "$OLD_IFS"
		failure
		echo
		zfs_set_ifs "$TMP_IFS"
	}
	zfs_log_progress_msg() { echo -n $"$1"; }
elif type einfo > /dev/null 2>&1 ; then
	# Gentoo functions
	zfs_log_begin_msg() { ebegin "$1"; }
	zfs_log_end_msg() { eend "$1"; }
	zfs_log_failure_msg() { eend "$1"; }
#	zfs_log_progress_msg() { echo -n "$1"; }
	zfs_log_progress_msg() { echo -n; }
else
	# Unknown - simple substitutes.
	zfs_log_begin_msg() { echo -n "$1"; }
	zfs_log_end_msg() {
		ret=$1
		if [ "$ret" -ge 1 ]; then
			echo " failed!"
		else
			echo " success"
		fi
		return "$ret"
	}
	zfs_log_failure_msg() { echo "$1"; }
	zfs_log_progress_msg() { echo -n "$1"; }
fi

# Paths to what we need
ZFS="/usr/local/sbin/zfs"
ZED="/usr/local/sbin/zed"
ZPOOL="/usr/local/sbin/zpool"
ZPOOL_CACHE="/usr/local/etc/zfs/zpool.cache"

# Sensible defaults
ZFS_MOUNT='yes'
ZFS_UNMOUNT='yes'

export ZFS ZED ZPOOL ZPOOL_CACHE ZFS_MOUNT ZFS_UNMOUNT

# Source zfs configuration, overriding the defaults
if [ -f /etc/sysconfig/zfs ]; then
	. /etc/sysconfig/zfs
fi

# ----------------------------------------------------

zfs_action()
{
	local MSG="$1";	shift
	local CMD="$*"
	local ret

	zfs_log_begin_msg "$MSG "
	$CMD
	ret=$?
	if [ "$ret" -eq 0 ]; then
		zfs_log_end_msg $ret
	else
		zfs_log_failure_msg $ret
	fi

	return $ret
}

# Returns
#   0 if daemon has been started
#   1 if daemon was already running
#   2 if daemon could not be started
#   3 if unsupported
#
zfs_daemon_start()
{
	local PIDFILE="$1";	shift
	local DAEMON_BIN="$1";	shift
	local DAEMON_ARGS="$*"

	if type start-stop-daemon > /dev/null 2>&1 ; then
		# LSB functions
		start-stop-daemon --start --quiet --pidfile "$PIDFILE" \
		    --exec "$DAEMON_BIN" --test > /dev/null || return 1

	        start-stop-daemon --start --quiet --exec "$DAEMON_BIN" -- \
		    $DAEMON_ARGS || return 2

		# On Debian GNU/Linux, there's a 'sendsigs' script that will
		# kill basically everything quite early and zed is stopped
		# much later than that. We don't want zed to be among them,
		# so add the zed pid to list of pids to ignore.
		if [ -f "$PIDFILE" -a -d /run/sendsigs.omit.d ]
		then
			ln -sf "$PIDFILE" /run/sendsigs.omit.d/zed
		fi
	elif type daemon > /dev/null 2>&1 ; then
	        # Fedora/RedHat functions
		daemon --pidfile "$PIDFILE" "$DAEMON_BIN" $DAEMON_ARGS
		return $?
	else
		# Unsupported
		return 3
	fi

	return 0
}

# Returns
#   0 if daemon has been stopped
#   1 if daemon was already stopped
#   2 if daemon could not be stopped
#   3 if unsupported
#
zfs_daemon_stop()
{
	local PIDFILE="$1"
	local DAEMON_BIN="$2"
	local DAEMON_NAME="$3"

	if type start-stop-daemon > /dev/null 2>&1 ; then
		# LSB functions
		start-stop-daemon --stop --quiet --retry=TERM/30/KILL/5 \
		    --pidfile "$PIDFILE" --name "$DAEMON_NAME"
		[ "$?" = 0 ] && rm -f "$PIDFILE"

		return $?
	elif type killproc > /dev/null 2>&1 ; then
		# Fedora/RedHat functions
		killproc -p "$PIDFILE" "$DAEMON_NAME"
		[ "$?" = 0 ] && rm -f "$PIDFILE"

		return $?
	else
		# Unsupported
		return 3
	fi

	return 0
}

# Returns status
zfs_daemon_status()
{
	local PIDFILE="$1"
	local DAEMON_BIN="$2"
	local DAEMON_NAME="$3"

	if type status_of_proc > /dev/null 2>&1 ; then
		# LSB functions
		status_of_proc "$DAEMON_NAME" "$DAEMON_BIN"
		return $?
	elif type status > /dev/null 2>&1 ; then
		# Fedora/RedHat functions
		status -p "$PIDFILE" "$DAEMON_NAME"
		return $?
	else
		# Unsupported
		return 3
	fi

	return 0
}

zfs_daemon_reload()
{
	local PIDFILE="$1"
	local DAEMON_NAME="$2"

	if type start-stop-daemon > /dev/null 2>&1 ; then
		# LSB functions
		start-stop-daemon --stop --signal 1 --quiet \
		    --pidfile "$PIDFILE" --name "$DAEMON_NAME"
		return $?
	elif type killproc > /dev/null 2>&1 ; then
		# Fedora/RedHat functions
                killproc -p "$PIDFILE" "$DAEMON_NAME" -HUP
		return $?
	else
		# Unsupported
		return 3
	fi

	return 0
}

zfs_installed()
{
	if [ ! -x "$ZPOOL" ]; then
		return 1
	else
		# Test if it works (will catch missing/broken libs etc)
		"$ZPOOL" -? > /dev/null 2>&1
		return $?
	fi

	if [ ! -x "$ZFS" ]; then
		return 2
	else
		# Test if it works (will catch missing/broken libs etc)
		"$ZFS" -? > /dev/null 2>&1
		return $?
	fi

	return 0
}

# Trigger udev and wait for it to settle.
udev_trigger()
{
	if [ -x /sbin/udevadm ]; then
		/sbin/udevadm trigger --action=change --subsystem-match=block
		/sbin/udevadm settle
	elif [ -x /sbin/udevsettle ]; then
		/sbin/udevtrigger
		/sbin/udevsettle
	fi
}

# Do a lot of checks to make sure it's 'safe' to continue with the import.
checksystem()
{
	if grep -qiE '(^|[^\\](\\\\)* )zfs=(off|no|0)( |$)' /proc/cmdline;
	then
		# Called with zfs=(off|no|0) - bail because we don't
		# want anything import, mounted or shared.
		# HOWEVER, only do this if we're called at the boot up
		# (from init), not if we're running interactively (as in
		# from the shell - we know what we're doing).
		[ -n "$init" ] && exit 3
	fi

	# Check if ZFS is installed.
	zfs_installed || return 5

	# Just make sure that /dev/zfs is created.
	udev_trigger

	return 0
}

get_root_pool()
{
	set -- $(mount | grep ' on / ')
	[ "$5" = "zfs" ] && echo "${1%%/*}"
}

# Check if a variable is 'yes' (any case) or '1'
# Returns TRUE if set.
check_boolean()
{
	local var="$1"

	echo "$var" | grep -Eiq "^yes$|^on$|^true$|^1$" && return 0 || return 1
}

check_module_loaded()
{
	module="$1"

	[ -r "/sys/module/${module}/version" ] && return 0 || return 1
}

load_module()
{
	module="$1"

	# Load the zfs module stack
	if ! check_module_loaded "$module"; then
		if ! /sbin/modprobe "$module"; then
			return 5
		fi
	fi
	return 0
}

# first parameter is a regular expression that filters mtab
read_mtab()
{
	local match="$1"
	local fs mntpnt fstype opts rest TMPFILE

	# Unset all MTAB_* variables
	unset $(env | grep ^MTAB_ | sed 's,=.*,,')

	while read -r fs mntpnt fstype opts rest; do
		if echo "$fs $mntpnt $fstype $opts" | grep -qE "$match"; then
			# * Fix problems (!?) in the mounts file. It will record
			#   'rpool 1' as 'rpool\0401' instead of 'rpool\00401'
			#   which seems to be the correct (at least as far as
			#   'printf' is concerned).
			# * We need to use the external echo, because the
			#   internal one would interpret the backslash code
			#   (incorrectly), giving us a 
 instead.
			mntpnt=$(/bin/echo "$mntpnt" | sed "s,\\\0,\\\00,g")
			fs=$(/bin/echo "$fs" | sed "s,\\\0,\\\00,")

			# Remove 'unwanted' characters.
			mntpnt=$(printf '%b\n' "$mntpnt" | sed -e 's,/,,g' \
			    -e 's,-,,g' -e 's,\.,,g' -e 's, ,,g')
			fs=$(printf '%b\n' "$fs")

			# Set the variable.
			eval export MTAB_$mntpnt=\"$fs\"
		fi
	done < /proc/self/mounts
}

in_mtab()
{
	local mntpnt="$1"
	# Remove 'unwanted' characters.
	mntpnt=$(printf '%b\n' "$mntpnt" | sed -e 's,/,,g' \
	    -e 's,-,,g' -e 's,\.,,g' -e 's, ,,g')   
	local var

	var="$(eval echo MTAB_$mntpnt)"
	[ "$(eval echo "$""$var")" != "" ]
	return "$?"
}

# first parameter is a regular expression that filters fstab
read_fstab()
{
	local match="$1"
	local i var TMPFILE

	# Unset all FSTAB_* variables
	unset $(env | grep ^FSTAB_ | sed 's,=.*,,')

	i=0
	while read -r fs mntpnt fstype opts; do
		echo "$fs" | egrep -qE '^#|^$' && continue
		echo "$mntpnt" | egrep -qE '^none|^swap' && continue
		echo "$fstype" | egrep -qE '^swap' && continue

		if echo "$fs $mntpnt $fstype $opts" | grep -qE "$match"; then
			eval export FSTAB_dev_$i="$fs"
			fs=$(printf '%b\n' "$fs" | sed 's,/,_,g')
			eval export FSTAB_$i="$mntpnt"

			i=$((i + 1))
		fi
	done < /etc/fstab
}

in_fstab()
{
	local var

	var="$(eval echo FSTAB_$1)"
	[ "${var}" != "" ]
	return $?
}

is_mounted()
{
	local mntpt="$1"
	local line

	mount | \
	    while read line; do
		if echo "$line" | grep -q " on $mntpt "; then
		    # returns:
		    #   0 on unsuccessful match
		    #   1 on a successful match
		    return 1
		fi
	    done

	# The negation will flip the subshell return result where the default
	# return value is 0 when a match is not found.
	return $(( !$? ))
}