kexec-tools/kdumpctl

#!/bin/bash
KEXEC=/sbin/kexec

KDUMP_KERNELVER=""
KDUMP_KERNEL=""
KDUMP_COMMANDLINE=""
KEXEC_ARGS=""
KDUMP_LOG_PATH="/var/log"
MKDUMPRD="/sbin/mkdumprd -f"
MKFADUMPRD="/sbin/mkfadumprd"
DRACUT_MODULES_FILE="/usr/lib/dracut/modules.txt"
SAVE_PATH=/var/crash
SSH_KEY_LOCATION=$DEFAULT_SSHKEY
INITRD_CHECKSUM_LOCATION="/boot/.fadump_initrd_checksum"
DUMP_TARGET=""
DEFAULT_INITRD=""
DEFAULT_INITRD_BAK=""
KDUMP_INITRD=""
TARGET_INITRD=""
FADUMP_REGISTER_SYS_NODE="/sys/kernel/fadump_registered"
#kdump shall be the default dump mode
DEFAULT_DUMP_MODE="kdump"
image_time=0

standard_kexec_args="-d -p"

# Some default values in case /etc/sysconfig/kdump doesn't include
KDUMP_COMMANDLINE_REMOVE="hugepages hugepagesz slub_debug"

declare -A OPT

if [[ -f /etc/sysconfig/kdump ]]; then
	. /etc/sysconfig/kdump
fi

[[ $dracutbasedir ]] || dracutbasedir=/usr/lib/dracut
. $dracutbasedir/dracut-functions.sh
. /lib/kdump/kdump-lib.sh
. /lib/kdump/kdump-logger.sh

#initiate the kdump logger
if ! dlog_init; then
	echo "failed to initiate the kdump logger."
	exit 1
fi

single_instance_lock()
{
	local rc timeout=5

	if ! exec 9> /var/lock/kdump; then
		derror "Create file lock failed"
		exit 1
	fi

	flock -n 9
	rc=$?

	while [[ $rc -ne 0 ]]; do
		dinfo "Another app is currently holding the kdump lock; waiting for it to exit..."
		flock -w $timeout 9
		rc=$?
	done
}

determine_dump_mode()
{
	# Check if firmware-assisted dump is enabled
	# if yes, set the dump mode as fadump
	if is_fadump_capable; then
		dinfo "Dump mode is fadump"
		DEFAULT_DUMP_MODE="fadump"
	fi
	ddebug "DEFAULT_DUMP_MODE=$DEFAULT_DUMP_MODE"
}

rebuild_fadump_initrd()
{
	if ! $MKFADUMPRD "$DEFAULT_INITRD_BAK" "$TARGET_INITRD" --kver "$KDUMP_KERNELVER"; then
		derror "mkfadumprd: failed to make fadump initrd"
		return 1
	fi

	sync -f "$TARGET_INITRD"
	return 0
}

check_earlykdump_is_enabled()
{
	grep -q -w "rd.earlykdump" /proc/cmdline
}

rebuild_kdump_initrd()
{
	ddebug "rebuild kdump initrd: $MKDUMPRD $TARGET_INITRD $KDUMP_KERNELVER"
	if ! $MKDUMPRD "$TARGET_INITRD" "$KDUMP_KERNELVER"; then
		derror "mkdumprd: failed to make kdump initrd"
		return 1
	fi

	if check_earlykdump_is_enabled; then
		dwarn "Tips: If early kdump is enabled, also require rebuilding the system initramfs to make the changes take effect for early kdump."
	fi

	sync -f "$TARGET_INITRD"
	return 0
}

rebuild_initrd()
{
	if [[ ! -w $(dirname "$TARGET_INITRD") ]]; then
		derror "$(dirname "$TARGET_INITRD") does not have write permission. Cannot rebuild $TARGET_INITRD"
		return 1
	fi

	if [[ $DEFAULT_DUMP_MODE == "fadump" ]]; then
		rebuild_fadump_initrd
	else
		rebuild_kdump_initrd
	fi
}

#$1: the files to be checked with IFS=' '
check_exist()
{
	for file in $1; do
		if [[ ! -e $file ]]; then
			derror "Error: $file not found."
			return 1
		fi
	done
}

#$1: the files to be checked with IFS=' '
check_executable()
{
	for file in $1; do
		if [[ ! -x $file ]]; then
			derror "Error: $file is not executable."
			return 1
		fi
	done
}

backup_default_initrd()
{
	ddebug "backup default initrd: $DEFAULT_INITRD"

	if [[ ! -f $DEFAULT_INITRD ]]; then
		return
	fi

	if [[ ! -e $DEFAULT_INITRD_BAK ]]; then
		dinfo "Backing up $DEFAULT_INITRD before rebuild."
		# save checksum to verify before restoring
		sha1sum "$DEFAULT_INITRD" > "$INITRD_CHECKSUM_LOCATION"
		if ! cp "$DEFAULT_INITRD" "$DEFAULT_INITRD_BAK"; then
			dwarn "WARNING: failed to backup $DEFAULT_INITRD."
			rm -f "$DEFAULT_INITRD_BAK"
		fi
	fi
}

restore_default_initrd()
{
	ddebug "restore default initrd: $DEFAULT_INITRD"

	if [[ ! -f $DEFAULT_INITRD ]]; then
		return
	fi

	# If a backup initrd exists, we must be switching back from
	# fadump to kdump. Restore the original default initrd.
	if [[ -f $DEFAULT_INITRD_BAK ]] && [[ -f $INITRD_CHECKSUM_LOCATION ]]; then
		# verify checksum before restoring
		backup_checksum=$(sha1sum "$DEFAULT_INITRD_BAK" | awk '{ print $1 }')
		default_checksum=$(awk '{ print $1 }' "$INITRD_CHECKSUM_LOCATION")
		if [[ $default_checksum != "$backup_checksum" ]]; then
			dwarn "WARNING: checksum mismatch! Can't restore original initrd.."
		else
			rm -f $INITRD_CHECKSUM_LOCATION
			if mv "$DEFAULT_INITRD_BAK" "$DEFAULT_INITRD"; then
				derror "Restoring original initrd as fadump mode is disabled."
				sync -f "$DEFAULT_INITRD"
			fi
		fi
	fi
}

_set_config()
{
	local opt=$1
	local val=$2

	if [[ -z $val ]]; then
		derror "Invalid kdump config value for option '$opt'"
		return 1
	fi

	if [[ -n ${OPT[$opt]} ]]; then
		if [[ $opt == _target ]]; then
			derror "More than one dump targets specified"
		else
			derror "Duplicated kdump config value of option $opt"
		fi
		return 1
	fi
	OPT[$opt]="$val"
}

parse_config()
{
	while read -r config_opt config_val; do
		case "$config_opt" in
		dracut_args)
			if [[ $config_val == *--mount* ]]; then
				if [[ $(echo "$config_val" | grep -o "\-\-mount" | wc -l) -ne 1 ]]; then
					derror 'Multiple mount targets specified in one "dracut_args".'
					return 1
				fi
				_set_config _target "$(get_dracut_args_target "$config_val")" || return 1
			fi
			;;
		raw)
			if [[ -d "/proc/device-tree/ibm,opal/dump" ]]; then
				dwarn "WARNING: Won't capture opalcore when 'raw' dump target is used."
			fi
			config_opt=_target
			;;
		ext[234] | minix | btrfs | xfs | nfs )
			config_opt=_target
			;;
		ssh)
			config_opt=_target
			DUMP_TARGET=$config_val
			;;
		sshkey)
			if [[ -z $config_val ]]; then
				derror "Invalid kdump config value for option '$config_opt'"
				return 1
			elif [[ -f $config_val ]]; then
				SSH_KEY_LOCATION=$(/usr/bin/readlink -m "$config_val")
			else
				dwarn "WARNING: '$config_val' doesn't exist, using default value '$SSH_KEY_LOCATION'"
			fi
			;;
		path)
			SAVE_PATH=$config_val
			;;
		core_collector | kdump_post | kdump_pre | extra_bins | extra_modules | failure_action | default | final_action | force_rebuild | force_no_rebuild | fence_kdump_args | fence_kdump_nodes | auto_reset_crashkernel) ;;

		net | options | link_delay | disk_timeout | debug_mem_level | blacklist)
			derror "Deprecated kdump config option: $config_opt. Refer to kdump.conf manpage for alternatives."
			return 1
			;;
		'')
			continue
			;;
		*)
			derror "Invalid kdump config option $config_opt"
			return 1
			;;
		esac

		_set_config "$config_opt" "$config_val" || return 1
	done <<< "$(kdump_read_conf)"

	check_failure_action_config || return 1
	check_final_action_config || return 1
	check_fence_kdump_config || return 1
	check_ssh_config || return 1

	return 0
}

# get_pcs_cluster_modified_files <image timestamp>
# return list of modified file for fence_kdump modified in Pacemaker cluster
get_pcs_cluster_modified_files()
{
	local time_stamp
	local modified_files

	is_generic_fence_kdump && return 1
	is_pcs_fence_kdump || return 1

	time_stamp=$(pcs cluster cib | xmllint --xpath 'string(/cib/@cib-last-written)' - | xargs -0 date +%s --date)

	if [[ -n $time_stamp ]] && [[ $time_stamp -gt $image_time ]]; then
		modified_files="cluster-cib"
	fi

	if [[ -f $FENCE_KDUMP_CONFIG_FILE ]]; then
		time_stamp=$(stat -c "%Y" "$FENCE_KDUMP_CONFIG_FILE")
		if [[ $time_stamp -gt $image_time ]]; then
			modified_files="$modified_files $FENCE_KDUMP_CONFIG_FILE"
		fi
	fi

	echo "$modified_files"
}

setup_initrd()
{
	if ! prepare_kdump_bootinfo; then
		derror "failed to prepare for kdump bootinfo."
		return 1
	fi

	DEFAULT_INITRD_BAK="$KDUMP_BOOTDIR/.$(basename "$DEFAULT_INITRD").default"
	if [[ $DEFAULT_DUMP_MODE == "fadump" ]]; then
		TARGET_INITRD="$DEFAULT_INITRD"

		# backup initrd for reference before replacing it
		# with fadump aware initrd
		backup_default_initrd
	else
		TARGET_INITRD="$KDUMP_INITRD"

		# check if a backup of default initrd exists. If yes,
		# it signifies a switch from fadump mode. So, restore
		# the backed up default initrd.
		restore_default_initrd
	fi
}

check_files_modified()
{
	local modified_files=""

	#also rebuild when Pacemaker cluster conf is changed and fence kdump is enabled.
	modified_files=$(get_pcs_cluster_modified_files)

	EXTRA_BINS=${OPT[kdump_post]}
	CHECK_FILES=${OPT[kdump_pre]}
	HOOKS="/etc/kdump/post.d/ /etc/kdump/pre.d/"
	if [[ -d /etc/kdump/post.d ]]; then
		for file in /etc/kdump/post.d/*; do
			if [[ -x $file ]]; then
				POST_FILES="$POST_FILES $file"
			fi
		done
	fi
	if [[ -d /etc/kdump/pre.d ]]; then
		for file in /etc/kdump/pre.d/*; do
			if [[ -x $file ]]; then
				PRE_FILES="$PRE_FILES $file"
			fi
		done
	fi
	HOOKS="$HOOKS $POST_FILES $PRE_FILES"
	CORE_COLLECTOR=$(echo "${OPT[core_collector]}" | awk '{print $1}')
	CORE_COLLECTOR=$(type -P "$CORE_COLLECTOR")
	# POST_FILES and PRE_FILES are already checked against executable, need not to check again.
	EXTRA_BINS="$EXTRA_BINS $CHECK_FILES"
	CHECK_FILES=${OPT[extra_bins]}
	EXTRA_BINS="$EXTRA_BINS $CHECK_FILES"
	files="$KDUMP_CONFIG_FILE $KDUMP_KERNEL $EXTRA_BINS $CORE_COLLECTOR"
	[[ -e /etc/fstab ]] && files="$files /etc/fstab"

	# Check for any updated extra module
	EXTRA_MODULES="${OPT[extra_modules]}"
	if [[ -n $EXTRA_MODULES ]]; then
		if [[ -e /lib/modules/$KDUMP_KERNELVER/modules.dep ]]; then
			files="$files /lib/modules/$KDUMP_KERNELVER/modules.dep"
		fi
		for _module in $EXTRA_MODULES; do
			if _module_file="$(modinfo --set-version "$KDUMP_KERNELVER" --filename "$_module" 2> /dev/null)"; then
				files="$files $_module_file"
				for _dep_modules in $(modinfo -F depends "$_module" | tr ',' ' '); do
					files="$files $(modinfo --set-version "$KDUMP_KERNELVER" --filename "$_dep_modules" 2> /dev/null)"
				done
			else
				# If it's not a module nor builtin, give an error
				if ! (modprobe --set-version "$KDUMP_KERNELVER" --dry-run "$_module" &> /dev/null); then
					dwarn "Module $_module not found"
				fi
			fi
		done
	fi

	# HOOKS is mandatory and need to check the modification time
	files="$files $HOOKS"
	check_exist "$files" && check_executable "$EXTRA_BINS" || return 2

	for file in $files; do
		if [[ -e $file ]]; then
			time_stamp=$(stat -c "%Y" "$file")
			if [[ $time_stamp -gt $image_time ]]; then
				modified_files="$modified_files $file"
			fi
			if [[ -L $file ]]; then
				file=$(readlink -m "$file")
				time_stamp=$(stat -c "%Y" "$file")
				if [[ $time_stamp -gt $image_time ]]; then
					modified_files="$modified_files $file"
				fi
			fi
		else
			dwarn "$file doesn't exist"
		fi
	done

	if [[ -n $modified_files ]]; then
		dinfo "Detected change(s) in the following file(s): $modified_files"
		return 1
	fi

	return 0
}

check_drivers_modified()
{
	local _target _new_drivers _old_drivers _module_name _module_filename

	# If it's dump target is on block device, detect the block driver
	_target=$(get_block_dump_target)
	if [[ -n $_target ]]; then
		_record_block_drivers()
		{
			local _drivers
			_drivers=$(udevadm info -a "/dev/block/$1" | sed -n 's/\s*DRIVERS=="\(\S\+\)"/\1/p')
			for _driver in $_drivers; do
				if ! [[ " $_new_drivers " == *" $_driver "* ]]; then
					_new_drivers="$_new_drivers $_driver"
				fi
			done

			ddebug "MAJ:MIN=$1 drivers='$_drivers'"
		}
		check_block_and_slaves_all _record_block_drivers "$(get_maj_min "$_target")"
	fi

	# Include watchdog drivers if watchdog module is not omitted
	is_dracut_mod_omitted watchdog || _new_drivers+=" $(get_watchdog_drvs)"
	[[ -z $_new_drivers ]] && return 0

	if is_fadump_capable; then
		_old_drivers="$(lsinitrd "$TARGET_INITRD" -f /usr/lib/dracut/fadump-kernel-modules.txt | tr '\n' ' ')"
	else
		_old_drivers="$(lsinitrd "$TARGET_INITRD" -f /usr/lib/dracut/hostonly-kernel-modules.txt | tr '\n' ' ')"
	fi

	ddebug "Modules required for kdump: '$_new_drivers'"
	ddebug "Modules included in old initramfs: '$_old_drivers'"
	for _driver in $_new_drivers; do
		# Skip deprecated/invalid driver name or built-in module
		_module_name=$(modinfo --set-version "$KDUMP_KERNELVER" -F name "$_driver" 2> /dev/null)
		_module_filename=$(modinfo --set-version "$KDUMP_KERNELVER" -n "$_driver" 2> /dev/null)
		if [[ -z $_module_name ]] || [[ -z $_module_filename ]] || [[ $_module_filename == *"(builtin)"* ]]; then
			continue
		fi
		if ! [[ " $_old_drivers " == *" $_module_name "* ]]; then
			dinfo "Detected change in block device driver, new loaded module: $_module_name"
			return 1
		fi
	done
}

check_fs_modified()
{
	local _old_dev _old_mntpoint _old_fstype
	local _new_dev _new_mntpoint _new_fstype
	local _target _dracut_args

	# No need to check in case of mount target specified via "dracut_args".
	if is_mount_in_dracut_args; then
		return 0
	fi

	# No need to check in case of raw target.
	# Currently we do not check also if ssh/nfs target is specified
	if is_ssh_dump_target || is_nfs_dump_target || is_raw_dump_target; then
		return 0
	fi

	_target=$(get_block_dump_target)
	_new_fstype=$(get_fs_type_from_target "$_target")
	if [[ -z $_target ]] || [[ -z $_new_fstype ]]; then
		derror "Dump target is invalid"
		return 2
	fi

	ddebug "_target=$_target _new_fstype=$_new_fstype"
	_new_dev=$(kdump_get_persistent_dev "$_target")
	if [[ -z $_new_dev ]]; then
		perror "Get persistent device name failed"
		return 2
	fi

	_new_mntpoint="$(get_kdump_mntpoint_from_target "$_target")"
	_dracut_args=$(lsinitrd "$TARGET_INITRD" -f usr/lib/dracut/build-parameter.txt)
	if [[ -z $_dracut_args ]]; then
		dwarn "Warning: No dracut arguments found in initrd"
		return 0
	fi

	# if --mount argument present then match old and new target, mount
	# point and file system. If any of them mismatches then rebuild
	if echo "$_dracut_args" | grep -q "\-\-mount"; then
		# shellcheck disable=SC2046
		set -- $(echo "$_dracut_args" | awk -F "--mount '" '{print $2}' | cut -d' ' -f1,2,3)
		_old_dev=$1
		_old_mntpoint=$2
		_old_fstype=$3
		[[ $_new_dev == "$_old_dev" && $_new_mntpoint == "$_old_mntpoint" && $_new_fstype == "$_old_fstype" ]] && return 0
	# otherwise rebuild if target device is not a root device
	else
		[[ $_target == "$(get_root_fs_device)" ]] && return 0
	fi

	dinfo "Detected change in File System"
	return 1
}

# returns 0 if system is not modified
# returns 1 if system is modified
# returns 2 if system modification is invalid
check_system_modified()
{
	local ret

	[[ -f $TARGET_INITRD ]] || return 1

	check_files_modified
	ret=$?
	if [[ $ret -ne 0 ]]; then
		return $ret
	fi

	check_fs_modified
	ret=$?
	if [[ $ret -ne 0 ]]; then
		return $ret
	fi

	check_drivers_modified
	ret=$?
	if [[ $ret -ne 0 ]]; then
		return $ret
	fi

	return 0
}

check_rebuild()
{
	local capture_capable_initrd="1"
	local force_rebuild force_no_rebuild
	local ret system_modified="0"

	setup_initrd || return 1

	force_no_rebuild=${OPT[force_no_rebuild]}
	force_no_rebuild=${force_no_rebuild:-0}
	if [[ $force_no_rebuild != "0" ]] && [[ $force_no_rebuild != "1" ]]; then
		derror "Error: force_no_rebuild value is invalid"
		return 1
	fi

	force_rebuild=${OPT[force_rebuild]}
	force_rebuild=${force_rebuild:-0}
	if [[ $force_rebuild != "0" ]] && [[ $force_rebuild != "1" ]]; then
		derror "Error: force_rebuild value is invalid"
		return 1
	fi

	if [[ $force_no_rebuild == "1" && $force_rebuild == "1" ]]; then
		derror "Error: force_rebuild and force_no_rebuild are enabled simultaneously in kdump.conf"
		return 1
	fi

	# Will not rebuild kdump initrd
	if [[ $force_no_rebuild == "1" ]]; then
		return 0
	fi

	#check to see if dependent files has been modified
	#since last build of the image file
	if [[ -f $TARGET_INITRD ]]; then
		image_time=$(stat -c "%Y" "$TARGET_INITRD" 2> /dev/null)

		#in case of fadump mode, check whether the default/target
		#initrd is already built with dump capture capability
		if [[ $DEFAULT_DUMP_MODE == "fadump" ]]; then
			capture_capable_initrd=$(lsinitrd -f $DRACUT_MODULES_FILE "$TARGET_INITRD" | grep -c -e ^kdumpbase$ -e ^zz-fadumpinit$)
		fi
	fi

	check_system_modified
	ret=$?
	if [[ $ret -eq 2 ]]; then
		return 1
	elif [[ $ret -eq 1 ]]; then
		system_modified="1"
	fi

	if [[ $image_time -eq 0 ]]; then
		dinfo "No kdump initial ramdisk found."
	elif [[ $capture_capable_initrd == "0" ]]; then
		dinfo "Rebuild $TARGET_INITRD with dump capture support"
	elif [[ $force_rebuild != "0" ]]; then
		dinfo "Force rebuild $TARGET_INITRD"
	elif [[ $system_modified != "0" ]]; then
		:
	else
		return 0
	fi

	dinfo "Rebuilding $TARGET_INITRD"
	rebuild_initrd
}

# On ppc64le LPARs, the keys trusted by firmware do not end up in
# .builtin_trusted_keys. So instead, add the key to the .ima keyring
function load_kdump_kernel_key()
{
	# this is only called inside is_secure_boot_enforced,
	# no need to retest

	# this is only required if DT /ibm,secure-boot is a file.
	# if it is a dir, we are on OpenPower and don't need this.
	if ! [[ -f /proc/device-tree/ibm,secure-boot ]]; then
		return
	fi

	KDUMP_KEY_ID=$(keyctl padd asymmetric kernelkey-$RANDOM %:.ima < "/usr/share/doc/kernel-keys/$KDUMP_KERNELVER/kernel-signing-ppc.cer")
}

# remove a previously loaded key. There's no real security implication
# to leaving it around, we choose to do this because it makes it easier
# to be idempotent and so as to reduce the potential for confusion.
function remove_kdump_kernel_key()
{
	if [[ -z $KDUMP_KEY_ID ]]; then
		return
	fi

	keyctl unlink "$KDUMP_KEY_ID" %:.ima
}

# Load the kdump kernel specified in /etc/sysconfig/kdump
# If none is specified, try to load a kdump kernel with the same version
# as the currently running kernel.
load_kdump()
{
	local ret

	KEXEC_ARGS=$(prepare_kexec_args "${KEXEC_ARGS}")
	KDUMP_COMMANDLINE=$(prepare_cmdline "${KDUMP_COMMANDLINE}" "${KDUMP_COMMANDLINE_REMOVE}" "${KDUMP_COMMANDLINE_APPEND}")

	# For secureboot enabled machines, use new kexec file based syscall.
	# Old syscall will always fail as it does not have capability to
	# to kernel signature verification.
	if is_secure_boot_enforced; then
		dinfo "Secure Boot is enabled. Using kexec file based syscall."
		KEXEC_ARGS="$KEXEC_ARGS -s"
		load_kdump_kernel_key
	fi

	ddebug "$KEXEC $KEXEC_ARGS $standard_kexec_args --command-line=$KDUMP_COMMANDLINE --initrd=$TARGET_INITRD $KDUMP_KERNEL"

	# The '12' represents an intermediate temporary file descriptor
	# to store the standard error file descriptor '2', and later
	# restore the error file descriptor with the file descriptor '12'
	# and release it.
	exec 12>&2
	exec 2>> $KDUMP_LOG_PATH/kdump.log
	PS4='+ $(date "+%Y-%m-%d %H:%M:%S") ${BASH_SOURCE}@${LINENO}: '
	set -x

	# shellcheck disable=SC2086
	$KEXEC $KEXEC_ARGS $standard_kexec_args \
		--command-line="$KDUMP_COMMANDLINE" \
		--initrd="$TARGET_INITRD" "$KDUMP_KERNEL"

	ret=$?
	set +x
	exec 2>&12 12>&-

	remove_kdump_kernel_key

	if [[ $ret == 0 ]]; then
		dinfo "kexec: loaded kdump kernel"
		return 0
	else
		derror "kexec: failed to load kdump kernel"
		return 1
	fi
}

check_ssh_config()
{
	local target

	[[ -n $DUMP_TARGET ]] || return 0

	[[ $DUMP_TARGET =~ .*@.* ]] || return 1
	target=$(ssh -G "$DUMP_TARGET" | sed  -n -e "s/^hostname[[:space:]]\+\([^[:space:]]*\).*$/\1/p")
	if [[ ${DUMP_TARGET#*@} != "$target" ]]; then
		derror "Invalid ssh destination $DUMP_TARGET provided."
		return 1
	fi

	return 0
}

# ipv6 host address may takes a long time to be ready.
# Instead of checking against ipv6 address, we just check the network reachable
# by the return val of 'ssh'
check_and_wait_network_ready()
{
	local start_time
	local warn_once=1
	local cur
	local diff
	local retval
	local errmsg

	[[ -n $DUMP_TARGET ]] || return 0

	start_time=$(date +%s)
	while true; do
		errmsg=$(ssh -i "$SSH_KEY_LOCATION" -o BatchMode=yes "$DUMP_TARGET" mkdir -p "$SAVE_PATH" 2>&1)
		retval=$?

		# ssh exits with the exit status of the remote command or with 255 if an error occurred
		if [[ $retval -eq 0 ]]; then
			return 0
		elif [[ $retval -ne 255 ]]; then
			derror "Could not create $DUMP_TARGET:$SAVE_PATH, you should check the privilege on server side"
			return 1
		fi

		# if server removes the authorized_keys or, no /root/.ssh/kdump_id_rsa
		ddebug "$errmsg"
		if echo "$errmsg" | grep -q "Permission denied\|No such file or directory\|Host key verification failed"; then
			derror "Could not create $DUMP_TARGET:$SAVE_PATH, you probably need to run \"kdumpctl propagate\""
			return 1
		fi

		if [[ $warn_once -eq 1 ]]; then
			dwarn "Network dump target is not usable, waiting for it to be ready..."
			warn_once=0
		fi

		cur=$(date +%s)
		diff=$((cur - start_time))
		# time out after 180s
		if [[ $diff -gt 180 ]]; then
			break
		fi
		sleep 1
	done

	dinfo "Could not create $DUMP_TARGET:$SAVE_PATH, ipaddr is not ready yet. You should check network connection"
	return 1
}

propagate_ssh_key()
{
	local SSH_USER SSH_SERVER

	parse_config || return 1

	if [[ -z $DUMP_TARGET ]] ; then
		derror "No ssh destination defined in $KDUMP_CONFIG_FILE."
		derror "Please verify that $KDUMP_CONFIG_FILE contains 'ssh <user>@<host>' and that it is properly formatted."
		exit 1
	fi

	local KEYFILE=$SSH_KEY_LOCATION

	#Check to see if we already created key, if not, create it.
	if [[ -f $KEYFILE ]]; then
		dinfo "Using existing keys..."
	else
		dinfo "Generating new ssh keys... "
		/usr/bin/ssh-keygen -t rsa -f "$KEYFILE" -N "" &> /dev/null
		dinfo "done."
	fi

	SSH_USER=${DUMP_TARGET%@*}
	SSH_SERVER=${DUMP_TARGET#*@}
	if ssh-copy-id -i "$KEYFILE" "$DUMP_TARGET"; then
		dinfo "$KEYFILE has been added to ~$SSH_USER/.ssh/authorized_keys on $SSH_SERVER"
		return 0
	else
		derror "Failed to propagate ssh key, could not transfer $KEYFILE to $SSH_SERVER"
		exit 1
	fi
}

show_reserved_mem()
{
	local mem
	local mem_mb

	mem=$(< /sys/kernel/kexec_crash_size)
	mem_mb=$((mem / 1024 / 1024))

	dinfo "Reserved ${mem_mb}MB memory for crash kernel"
}

check_current_fadump_status()
{
	# Check if firmware-assisted dump has been registered.
	rc=$(< $FADUMP_REGISTER_SYS_NODE)
	[[ $rc -eq 1 ]] && return 0
	return 1
}

check_current_status()
{
	if [[ $DEFAULT_DUMP_MODE == "fadump" ]]; then
		check_current_fadump_status
	else
		check_current_kdump_status
	fi
}

save_raw()
{
	local kdump_dir
	local raw_target

	raw_target=$(kdump_get_conf_val raw)
	[[ -z $raw_target ]] && return 0
	[[ -b $raw_target ]] || {
		derror "raw partition $raw_target not found"
		return 1
	}
	check_fs=$(lsblk --nodeps -npo FSTYPE "$raw_target")
	if [[ $(echo "$check_fs" | wc -w) -ne 0 ]]; then
		dwarn "Warning: Detected '$check_fs' signature on $raw_target, data loss is expected."
		return 0
	fi
	kdump_dir=${OPT[path]}
	if [[ -z ${kdump_dir} ]]; then
		coredir="/var/crash/$(date +"%Y-%m-%d-%H:%M")"
	else
		coredir="${kdump_dir}/$(date +"%Y-%m-%d-%H:%M")"
	fi

	mkdir -p "$coredir"
	[[ -d $coredir ]] || {
		derror "failed to create $coredir"
		return 1
	}
	if makedumpfile -R "$coredir/vmcore" < "$raw_target" > /dev/null 2>&1; then
		# dump found
		dinfo "Dump saved to $coredir/vmcore"
		# wipe makedumpfile header
		dd if=/dev/zero of="$raw_target" bs=1b count=1 2> /dev/null
	else
		rm -rf "$coredir"
	fi

	return 0
}

local_fs_dump_target()
{
	local _target

	if _target=$(grep -E "^ext[234]|^xfs|^btrfs|^minix" /etc/kdump.conf); then
		echo "$_target" | awk '{print $2}'
	fi
}

path_to_be_relabeled()
{
	local _path _target _mnt="/" _rmnt

	if is_user_configured_dump_target; then
		if is_mount_in_dracut_args; then
			return
		fi

		_target=$(local_fs_dump_target)
		if [[ -n $_target ]]; then
			_mnt=$(get_mntpoint_from_target "$_target")
			if ! is_mounted "$_mnt"; then
				return
			fi
		else
			return
		fi
	fi

	_path=$(get_save_path)
	# if $_path is masked by other mount, we will not relabel it.
	_rmnt=$(df "$_mnt/$_path" 2> /dev/null | tail -1 | awk '{ print $NF }')
	if [[ $_rmnt == "$_mnt" ]]; then
		echo "$_mnt/$_path"
	fi
}

selinux_relabel()
{
	local _path _i _attr

	_path=$(path_to_be_relabeled)
	if [[ -z $_path ]] || ! [[ -d $_path ]]; then
		return
	fi

	while IFS= read -r -d '' _i; do
		_attr=$(getfattr -m "security.selinux" "$_i" 2> /dev/null)
		if [[ -z $_attr ]]; then
			restorecon "$_i"
		fi
	done < <(find "$_path" -print0)
}

check_fence_kdump_config()
{
	local hostname
	local ipaddrs
	local nodes

	hostname=$(hostname)
	ipaddrs=$(hostname -I)
	nodes=${OPT[fence_kdump_nodes]}

	for node in $nodes; do
		if [[ $node == "$hostname" ]]; then
			derror "Option fence_kdump_nodes cannot contain $hostname"
			return 1
		fi
		# node can be ipaddr
		if echo "$ipaddrs " | grep -q "$node "; then
			derror "Option fence_kdump_nodes cannot contain $node"
			return 1
		fi
	done

	return 0
}

check_dump_feasibility()
{
	if [[ $DEFAULT_DUMP_MODE == "fadump" ]]; then
		return 0
	fi

	check_kdump_feasibility
}

start_fadump()
{
	echo 1 > $FADUMP_REGISTER_SYS_NODE
	if ! check_current_fadump_status; then
		derror "fadump: failed to register"
		return 1
	fi

	dinfo "fadump: registered successfully"
	return 0
}

start_dump()
{
	if [[ $DEFAULT_DUMP_MODE == "fadump" ]]; then
		start_fadump
	else
		load_kdump
	fi
}

check_failure_action_config()
{
	local default_option
	local failure_action
	local option="failure_action"

	default_option=${OPT[default]}
	failure_action=${OPT[failure_action]}

	if [[ -z $failure_action ]] && [[ -z $default_option ]]; then
		return 0
	elif [[ -n $failure_action ]] && [[ -n $default_option ]]; then
		derror "Cannot specify 'failure_action' and 'default' option together"
		return 1
	fi

	if [[ -n $default_option ]]; then
		option="default"
		failure_action="$default_option"
	fi

	case "$failure_action" in
	reboot | halt | poweroff | shell | dump_to_rootfs)
		return 0
		;;
	*)
		dinfo $"Usage kdump.conf: $option {reboot|halt|poweroff|shell|dump_to_rootfs}"
		return 1
		;;
	esac
}

check_final_action_config()
{
	local final_action

	final_action=${OPT[final_action]}
	if [[ -z $final_action ]]; then
		return 0
	else
		case "$final_action" in
		reboot | halt | poweroff)
			return 0
			;;
		*)
			dinfo $"Usage kdump.conf: final_action {reboot|halt|poweroff}"
			return 1
			;;
		esac
	fi
}

start()
{
	if ! check_dump_feasibility; then
		derror "Starting kdump: [FAILED]"
		return 1
	fi

	if ! parse_config; then
		derror "Starting kdump: [FAILED]"
		return 1
	fi

	if sestatus 2> /dev/null | grep -q "SELinux status.*enabled"; then
		selinux_relabel
	fi

	if ! save_raw; then
		derror "Starting kdump: [FAILED]"
		return 1
	fi

	if check_current_status; then
		dwarn "Kdump already running: [WARNING]"
		return 0
	fi

	if ! check_and_wait_network_ready; then
		derror "Starting kdump: [FAILED]"
		return 1
	fi

	if ! check_rebuild; then
		derror "Starting kdump: [FAILED]"
		return 1
	fi

	if ! start_dump; then
		derror "Starting kdump: [FAILED]"
		return 1
	fi

	dinfo "Starting kdump: [OK]"
}

reload()
{
	if ! check_current_status; then
		dwarn "Kdump was not running: [WARNING]"
	fi

	if [[ $DEFAULT_DUMP_MODE == "fadump" ]]; then
		reload_fadump
		return
	else
		if ! stop_kdump; then
			derror "Stopping kdump: [FAILED]"
			return 1
		fi
	fi

	dinfo "Stopping kdump: [OK]"

	if ! setup_initrd; then
		derror "Starting kdump: [FAILED]"
		return 1
	fi

	if ! start_dump; then
		derror "Starting kdump: [FAILED]"
		return 1
	fi

	dinfo "Starting kdump: [OK]"
}

stop_fadump()
{
	echo 0 > $FADUMP_REGISTER_SYS_NODE
	if check_current_fadump_status; then
		derror "fadump: failed to unregister"
		return 1
	fi

	dinfo "fadump: unregistered successfully"
	return 0
}

stop_kdump()
{
	if is_secure_boot_enforced; then
		$KEXEC -s -p -u
	else
		$KEXEC -p -u
	fi

	# shellcheck disable=SC2181
	if [[ $? != 0 ]]; then
		derror "kexec: failed to unload kdump kernel"
		return 1
	fi

	dinfo "kexec: unloaded kdump kernel"
	return 0
}

reload_fadump()
{
	if echo 1 > $FADUMP_REGISTER_SYS_NODE; then
		dinfo "fadump: re-registered successfully"
		return 0
	else
		# FADump could fail on older kernel where re-register
		# support is not enabled. Try stop/start from userspace
		# to handle such scenario.
		if stop_fadump; then
			start_fadump
			return
		fi
	fi

	return 1
}

stop()
{
	if [[ $DEFAULT_DUMP_MODE == "fadump" ]]; then
		stop_fadump
	else
		stop_kdump
	fi

	# shellcheck disable=SC2181
	if [[ $? != 0 ]]; then
		derror "Stopping kdump: [FAILED]"
		return 1
	fi

	dinfo "Stopping kdump: [OK]"
	return 0
}

rebuild()
{
	parse_config || return 1
	check_and_wait_network_ready || return 1

	setup_initrd || return 1

	dinfo "Rebuilding $TARGET_INITRD"
	rebuild_initrd
}

do_estimate()
{
	local kdump_mods
	local -A large_mods
	local baseline
	local kernel_size mod_size initrd_size baseline_size runtime_size reserved_size estimated_size recommended_size
	local size_mb=$((1024 * 1024))

	setup_initrd
	if [[ ! -f $TARGET_INITRD ]]; then
		derror "kdumpctl estimate: kdump initramfs is not built yet."
		exit 1
	fi

	kdump_mods="$(lsinitrd "$TARGET_INITRD" -f /usr/lib/dracut/hostonly-kernel-modules.txt | tr '\n' ' ')"
	baseline=$(kdump_get_arch_recommend_size)
	if [[ ${baseline: -1} == "M" ]]; then
		baseline=${baseline%M}
	elif [[ ${baseline: -1} == "G" ]]; then
		baseline=$((${baseline%G} * 1024))
	elif [[ ${baseline: -1} == "T" ]]; then
		baseline=$((${baseline%Y} * 1048576))
	fi

	# The default pre-reserved crashkernel value
	baseline_size=$((baseline * size_mb))
	# Current reserved crashkernel size
	reserved_size=$(< /sys/kernel/kexec_crash_size)
	# A pre-estimated value for userspace usage and kernel
	# runtime allocation, 64M should good for most cases
	runtime_size=$((64 * size_mb))
	# Kernel image size
	kernel_size=$(get_kernel_size "$KDUMP_KERNEL")
	# Kdump initramfs size
	initrd_size=$(du -b "$TARGET_INITRD" | awk '{print $1}')
	# Kernel modules static size after loaded
	mod_size=0
	while read -r _name _size _; do
		if [[ " $kdump_mods " != *" $_name "* ]]; then
			continue
		fi
		mod_size=$((mod_size + _size))

		# Mark module with static size larger than 2M as large module
		if [[ $((_size / size_mb)) -ge 1 ]]; then
			large_mods[$_name]=$_size
		fi
	done <<< "$(< /proc/modules)"

	# Extra memory usage required for LUKS2 decryption
	crypt_size=0
	for _dev in $(get_all_kdump_crypt_dev); do
		_crypt_info=$(cryptsetup luksDump "/dev/block/$_dev")
		[[ $(echo "$_crypt_info" | sed -n "s/^Version:\s*\(.*\)/\1/p") == "2" ]] || continue
		for _mem in $(echo "$_crypt_info" | sed -n "s/\sMemory:\s*\(.*\)/\1/p" | sort -n); do
			crypt_size=$((crypt_size + _mem * 1024))
			break
		done
	done
	[[ $crypt_size -ne 0 ]] && echo -e "Encrypted kdump target requires extra memory, assuming using the keyslot with minimun memory requirement\n"

	estimated_size=$((kernel_size + mod_size + initrd_size + runtime_size + crypt_size))
	if [[ $baseline_size -gt $estimated_size ]]; then
		recommended_size=$baseline_size
	else
		recommended_size=$estimated_size
	fi

	echo "Reserved crashkernel:    $((reserved_size / size_mb))M"
	echo "Recommended crashkernel: $((recommended_size / size_mb))M"
	echo
	echo "Kernel image size:   $((kernel_size / size_mb))M"
	echo "Kernel modules size: $((mod_size / size_mb))M"
	echo "Initramfs size:      $((initrd_size / size_mb))M"
	echo "Runtime reservation: $((runtime_size / size_mb))M"
	[[ $crypt_size -ne 0 ]] &&
		echo "LUKS required size:  $((crypt_size / size_mb))M"
	echo -n "Large modules:"
	if [[ ${#large_mods[@]} -eq 0 ]]; then
		echo " <none>"
	else
		echo ""
		for _mod in "${!large_mods[@]}"; do
			echo "    $_mod: ${large_mods[$_mod]}"
		done
	fi

	if [[ $reserved_size -lt $recommended_size ]]; then
		echo "WARNING: Current crashkernel size is lower than recommended size $((recommended_size / size_mb))M."
	fi
}

get_default_crashkernel()
{
	local _dump_mode=$1

	kdump_get_arch_recommend_crashkernel "$_dump_mode"
}

# Read kernel cmdline parameter for a specific kernel
# $1: kernel path, DEFAULT or kernel path, ALL not accepted
# $2: kernel cmldine parameter
get_grub_kernel_boot_parameter()
{
	local _kernel_path=$1 _para=$2

	[[ $_kernel_path == ALL ]] && derror "kernel_path=ALL invalid for get_grub_kernel_boot_parameter" && return 1
	grubby --info="$_kernel_path" | sed -En -e "/^args=.*$/{s/^.*(\s|\")${_para}=(\S*).*\"$/\2/p;q}"
}

# get dump mode by fadump value
# return
#  - fadump, if fadump=on or fadump=nocma
#  - kdump, if fadump=off or empty fadump, return kdump
#  - error if otherwise
get_dump_mode_by_fadump_val()
{
	local _fadump_val=$1

	if [[ -z $_fadump_val ]] || [[ $_fadump_val == off ]]; then
		echo -n kdump
	elif [[ $_fadump_val == on ]] || [[ $_fadump_val == nocma ]]; then
		echo -n fadump
	else
		derror "invalid fadump=$_fadump_val"
		return 1
	fi
}

# get dump mode of a specific kernel
# based on its fadump kernel cmdline parameter
get_dump_mode_by_kernel()
{
	local _kernel_path=$1 _fadump_val _dump_mode

	_fadump_val=$(get_grub_kernel_boot_parameter "$_kernel_path" fadump)
	if _dump_mode=$(get_dump_mode_by_fadump_val "$_fadump_val"); then
		echo -n "$_dump_mode"
	else
		derror "failed to get dump mode for kernel $_kernel_path"
		exit
	fi
}

_filter_grubby_kernel_str()
{
	local _grubby_kernel_str=$1
	echo -n "$_grubby_kernel_str" | sed -n -e 's/^kernel="\(.*\)"/\1/p'
}

_find_kernel_path_by_release()
{
	local _release="$1" _grubby_kernel_str _kernel_path
	_grubby_kernel_str=$(grubby --info ALL | grep "^kernel=.*$_release")
	_kernel_path=$(_filter_grubby_kernel_str "$_grubby_kernel_str")
	if [[ -z $_kernel_path ]]; then
		derror "kernel $_release doesn't exist"
		return 1
	fi
	echo -n "$_kernel_path"
}

_get_current_running_kernel_path()
{
	local _release _path

	_release=$(uname -r)
	if _path=$(_find_kernel_path_by_release "$_release"); then
		echo -n "$_path"
	else
		return 1
	fi
}

_update_grub()
{
	local _kernel_path=$1 _crashkernel=$2 _dump_mode=$3 _fadump_val=$4

	if is_atomic; then
		if rpm-ostree kargs | grep -q "crashkernel="; then
			rpm-ostree kargs --replace="crashkernel=$_crashkernel"
		else
			rpm-ostree kargs --append="crashkernel=$_crashkernel"
		fi
	else
		[[ -f /etc/zipl.conf ]] && zipl_arg="--zipl"
		grubby --args "crashkernel=$_crashkernel" --update-kernel "$_kernel_path" $zipl_arg
		if [[ $_dump_mode == kdump ]]; then
			grubby --remove-args="fadump" --update-kernel "$_kernel_path"
		else
			grubby --args="fadump=$_fadump_val" --update-kernel "$_kernel_path"
		fi
	fi
	[[ $zipl_arg ]] && zipl > /dev/null
}

_valid_grubby_kernel_path()
{
	[[ -n "$1" ]] && grubby --info="$1" > /dev/null 2>&1
}

# return all the kernel paths given a grubby kernel-path
#
# $1: kernel path accepted by grubby, e.g. DEFAULT, ALL,
#     /boot/vmlinuz-`uname -r`
# return: kernel paths separated by space
_get_all_kernels_from_grubby()
{
	local _kernels _line _kernel_path _grubby_kernel_path=$1

	for _line in $(grubby --info "$_grubby_kernel_path" | grep "^kernel="); do
		_kernel_path=$(_filter_grubby_kernel_str "$_line")
		_kernels="$_kernels $_kernel_path"
	done
	echo -n "$_kernels"
}

GRUB_ETC_DEFAULT="/etc/default/grub"
# Update a kernel parameter in default grub conf
#
# If a value is specified, it will be inserted in the end. Otherwise it
# would remove given kernel parameter.
#
# Note this function doesn't address the following cases,
# 1. The kernel ignores everything on the command line after a '--'. So
#    simply adding the new entry to the end will fail if the cmdline
#    contains a --.
# 2. If the value for a parameter contains spaces it can be quoted using
#    double quotes, for example param="value with spaces". This will
#    break the [^[:space:]\"] regex for the value.
# 3. Dashes and underscores in the parameter name are equivalent. So
#    some_parameter and some-parameter are identical.
# 4. Some parameters, e.g. efivar_ssdt, can be given multiple times.
# 5. Some kernel parameters, e.g. quiet, doesn't have value
#
# $1: the name of the kernel command line parameter
# $2: new value. If empty, given parameter would be removed
_update_kernel_arg_in_grub_etc_default()
{
	local _para=$1 _val=$2 _para_val

	if [[ -n $_val ]]; then
		_para_val="$_para=$_val"
	fi

	# Update the command line /etc/default/grub, i.e.
	# on the line that starts with 'GRUB_CMDLINE_LINUX=',
	#       1) remove $para=$val if the it's the first arg
	#       2) remove all occurences of $para=$val
	#       3) insert $_para_val to end
	#       4) remove duplicate spaces left over by 1) or 2) or 3)
	#       5) remove space at the beginning of the string left over by 1) or 2) or 3)
	#       6) remove space at the end of the string left over by 1) or 2) or 3)
	sed -i -E "/^GRUB_CMDLINE_LINUX=/ {
         s/\"${_para}=[^[:space:]\"]*/\"/g;
         s/[[:space:]]+${_para}=[^[:space:]\"]*/ /g;
         s/\"$/ ${_para_val}\"/
         s/[[:space:]]+/ /g;
         s/(\")[[:space:]]+/\1/g;
         s/[[:space:]]+(\")/\1/g;
         }" "$GRUB_ETC_DEFAULT"
}

# Read the kernel arg in default grub conf.

# Note reading a kernel parameter that doesn't have a value isn't supported.
#
# $1: the name of the kernel command line parameter
_read_kernel_arg_in_grub_etc_default()
{
	sed -n -E "s/^GRUB_CMDLINE_LINUX=.*[[:space:]\"]${1}=([^[:space:]\"]*).*$/\1/p" "$GRUB_ETC_DEFAULT"
}

reset_crashkernel()
{
	local _opt _val _dump_mode _fadump_val _reboot _grubby_kernel_path _kernel _kernels
	local _old_crashkernel _new_crashkernel _new_dump_mode _crashkernel_changed
	local _new_fadump_val _old_fadump_val _what_is_updated

	for _opt in "$@"; do
		case "$_opt" in
			--fadump=*)
				_val=${_opt#*=}
				if _dump_mode=$(get_dump_mode_by_fadump_val $_val); then
					_fadump_val=$_val
				else
					derror "failed to determine dump mode"
					exit
				fi
				;;
			--kernel=*)
				_val=${_opt#*=}
				if ! _valid_grubby_kernel_path $_val; then
					derror "Invalid $_opt, please specify a valid kernel path, ALL or DEFAULT"
					exit
				fi
				_grubby_kernel_path=$_val
				;;
			--reboot)
				_reboot=yes
				;;
			*)
				derror "$_opt not recognized"
				exit 1
				;;
		esac
	done

	# 1. CoreOS uses "rpm-ostree kargs" instead of grubby to manage kernel command
	#    line. --kernel=ALL doesn't make sense for CoreOS.
	# 2. CoreOS doesn't support POWER so the dump mode is always kdump.
	# 3. "rpm-ostree kargs" would prompt the user to reboot the system after
	#    modifying the kernel command line so there is no need for kexec-tools
	#    to repeat it.
	if is_atomic; then
		_old_crashkernel=$(rpm-ostree kargs | sed -n -E 's/.*(^|\s)crashkernel=(\S*).*/\2/p')
		_new_dump_mode=kdump
		_new_crashkernel=$(kdump_get_arch_recommend_crashkernel "$_new_dump_mode")
		if [[ $_old_crashkernel != "$_new_crashkernel" ]]; then
			_update_grub "" "$_new_crashkernel" "$_new_dump_mode" ""
			if [[ $_reboot == yes ]]; then
				systemctl reboot
			fi
		fi
		return
	fi

	# For non-ppc64le systems, the dump mode is always kdump since only ppc64le
	# has FADump.
	if [[ -z $_dump_mode && $(uname -m) != ppc64le ]]; then
		_dump_mode=kdump
		_fadump_val=off
	fi

	# If the dump mode is determined, we can also know the default crashkernel value
	if [[ -n $_dump_mode ]]; then
		_crashkernel=$(kdump_get_arch_recommend_crashkernel "$_dump_mode")
	fi

	# If --kernel-path=ALL, update GRUB_CMDLINE_LINUX in /etc/default/grub.
	#
	# An exception case is when the ppc64le user doesn't specify the fadump value.
	# In this case, the dump mode would be determined by parsing the kernel
	# command line of the kernel(s) to be updated thus don't update GRUB_CMDLINE_LINUX.
	#
	# The following code has been simplified because of what has been done early,
	#   - set the dump mode as kdump for non-ppc64le cases
	#   - retrieved the default crashkernel value for given dump mode
	if [[ $_grubby_kernel_path == ALL && -n $_dump_mode ]]; then
		_update_kernel_arg_in_grub_etc_default crashkernel "$_crashkernel"
		# remove the fadump if fadump is disabled
		if [[ $_fadump_val == off ]]; then
			_fadump_val=""
		fi
		_update_kernel_arg_in_grub_etc_default fadump "$_fadump_val"
	fi

	# If kernel-path not specified, either
	#  - use KDUMP_KERNELVER if it's defined
	#  - use current running kernel
	if [[ -z $_grubby_kernel_path ]]; then
		if [[ -z $KDUMP_KERNELVER ]] ||
			! _kernel_path=$(_find_kernel_path_by_release "$KDUMP_KERNELVER"); then
					if ! _kernel_path=$(_get_current_running_kernel_path); then
						derror "no running kernel found"
						exit 1
					fi
		fi
		_kernels=$_kernel_path
	else
		_kernels=$(_get_all_kernels_from_grubby "$_grubby_kernel_path")
	fi

	for _kernel in $_kernels; do
		if [[ -z $_dump_mode ]]; then
			_new_dump_mode=$(get_dump_mode_by_kernel "$_kernel")
			_new_crashkernel=$(kdump_get_arch_recommend_crashkernel "$_new_dump_mode")
			_new_fadump_val=$(get_grub_kernel_boot_parameter "$_kernel" fadump)
		else
			_new_dump_mode=$_dump_mode
			_new_crashkernel=$_crashkernel
			_new_fadump_val=$_fadump_val
		fi

		_old_crashkernel=$(get_grub_kernel_boot_parameter "$_kernel" crashkernel)
		_old_fadump_val=$(get_grub_kernel_boot_parameter "$_kernel" fadump)
		if [[ $_old_crashkernel != "$_new_crashkernel" || $_old_fadump_val != "$_new_fadump_val" ]]; then
			_update_grub "$_kernel" "$_new_crashkernel" "$_new_dump_mode" "$_new_fadump_val"
			if [[ $_reboot != yes ]]; then
				if [[ $_old_crashkernel != "$_new_crashkernel" ]]; then
					_what_is_updated="Updated crashkernel=$_new_crashkernel"
				else
					# This case happens only when switching between fadump=on and fadump=nocma
					_what_is_updated="Updated fadump=$_new_fadump_val"
				fi
				dwarn "$_what_is_updated for kernel=$_kernel. Please reboot the system for the change to take effect."
			fi
			_crashkernel_changed=yes
		fi
	done

	if [[ $_reboot == yes && $_crashkernel_changed == yes ]]; then
		reboot
	fi
}

# update the crashkernel value in GRUB_ETC_DEFAULT if necessary
#
# called by reset_crashkernel_after_update and inherit its array variable
# _crashkernel_vals
update_crashkernel_in_grub_etc_default_after_update()
{
	local _crashkernel _fadump_val
	local _dump_mode _old_default_crashkernel _new_default_crashkernel

	_crashkernel=$(_read_kernel_arg_in_grub_etc_default crashkernel)

	if [[ -z $_crashkernel ]]; then
		return
	fi

	_fadump_val=$(_read_kernel_arg_in_grub_etc_default fadump)
	_dump_mode=$(get_dump_mode_by_fadump_val "$_fadump_val")

	_old_default_crashkernel=${_crashkernel_vals[old_${_dump_mode}]}
	_new_default_crashkernel=${_crashkernel_vals[new_${_dump_mode}]}

	if [[ $_crashkernel == auto ]] ||
		  [[ $_crashkernel == "$_old_default_crashkernel" &&
		     $_new_default_crashkernel != "$_old_default_crashkernel" ]]; then
			_update_kernel_arg_in_grub_etc_default crashkernel "$_new_default_crashkernel"
	fi
}

# shellcheck disable=SC2154 # false positive when dereferencing an array
reset_crashkernel_after_update()
{
	local _kernel _crashkernel _dump_mode _fadump_val _old_default_crashkernel _new_default_crashkernel
	declare -A _crashkernel_vals

	_crashkernel_vals[old_kdump]=$(cat /tmp/old_default_crashkernel 2> /dev/null)
	_crashkernel_vals[old_fadump]=$(cat /tmp/old_default_crashkernel_fadump 2> /dev/null)
	_crashkernel_vals[new_kdump]=$(get_default_crashkernel kdump)
	_crashkernel_vals[new_fadump]=$(get_default_crashkernel fadump)

	for _kernel in $(_get_all_kernels_from_grubby ALL); do
		_crashkernel=$(get_grub_kernel_boot_parameter "$_kernel" crashkernel)
		if [[ $_crashkernel == auto ]]; then
			reset_crashkernel "--kernel=$_kernel"
		elif [[ -n $_crashkernel ]]; then
			_dump_mode=$(get_dump_mode_by_kernel "$_kernel")
			_old_default_crashkernel=${_crashkernel_vals[old_${_dump_mode}]}
			_new_default_crashkernel=${_crashkernel_vals[new_${_dump_mode}]}
			if [[ $_crashkernel == "$_old_default_crashkernel" ]] &&
				[[ $_new_default_crashkernel != "$_old_default_crashkernel" ]]; then
				_fadump_val=$(get_grub_kernel_boot_parameter "$_kernel" fadump)
				if _update_grub "$_kernel" "$_new_default_crashkernel" "$_dump_mode" "$_fadump_val"; then
					echo "For kernel=$_kernel, crashkernel=$_new_default_crashkernel now."
				fi
			fi
		fi
	done

	update_crashkernel_in_grub_etc_default_after_update
}

# read the value of an environ variable from given environ file path
#
# The environment variable entries in /proc/[pid]/environ are separated
# by null bytes instead of by spaces.
#
# $1: environment variable
# $2: environ file path
read_proc_environ_var()
{
	local _var=$1 _environ_path=$2
	sed -n -E "s/.*(^|\x00)${_var}=([^\x00]*).*/\2/p" < "$_environ_path"
}

_OSBUILD_ENVIRON_PATH='/proc/1/environ'
_is_osbuild()
{
	[[ $(read_proc_environ_var container "$_OSBUILD_ENVIRON_PATH") == bwrap-osbuild ]]
}

reset_crashkernel_for_installed_kernel()
{
	local _installed_kernel _running_kernel _crashkernel _crashkernel_running
	local _dump_mode_running _fadump_val_running

	if ! _installed_kernel=$(_find_kernel_path_by_release "$1"); then
		exit 1
	fi

	if _is_osbuild; then
		if ! grep -qs crashkernel= /etc/kernel/cmdline; then
			reset_crashkernel "--kernel=$_installed_kernel"
		fi
		return
	fi

	if ! _running_kernel=$(_get_current_running_kernel_path); then
		derror "Couldn't find current running kernel"
		exit
	fi

	_crashkernel=$(get_grub_kernel_boot_parameter "$_installed_kernel" crashkernel)
	_crashkernel_running=$(get_grub_kernel_boot_parameter "$_running_kernel" crashkernel)
	_dump_mode_running=$(get_dump_mode_by_kernel "$_running_kernel")
	_fadump_val_running=$(get_grub_kernel_boot_parameter "$_kernel" fadump)

	if [[ $_crashkernel != "$_crashkernel_running" ]]; then
		if _update_grub "$_installed_kernel" "$_crashkernel_running" "$_dump_mode_running" "$_fadump_val_running"; then
			echo "kexec-tools has reset $_installed_kernel to use the new default crashkernel value $_crashkernel_running"
		fi
	fi
}

if [[ ! -f $KDUMP_CONFIG_FILE ]]; then
	derror "Error: No kdump config file found!"
	exit 1
fi

main()
{
	# Determine if the dump mode is kdump or fadump
	determine_dump_mode

	case "$1" in
	start)
		start
		;;
	stop)
		stop
		;;
	status)
		EXIT_CODE=0
		check_current_status
		case "$?" in
		0)
			dinfo "Kdump is operational"
			EXIT_CODE=0
			;;
		1)
			dinfo "Kdump is not operational"
			EXIT_CODE=3
			;;
		esac
		exit $EXIT_CODE
		;;
	reload)
		reload
		;;
	restart)
		stop
		start
		;;
	rebuild)
		rebuild
		;;
	condrestart) ;;

	propagate)
		propagate_ssh_key
		;;
	showmem)
		show_reserved_mem
		;;
	estimate)
		do_estimate
		;;
	get-default-crashkernel)
		get_default_crashkernel "$2"
		;;
	reset-crashkernel)
		shift
		reset_crashkernel "$@"
		;;
	reset-crashkernel-after-update)
		if [[ $(kdump_get_conf_val auto_reset_crashkernel) != no ]]; then
			reset_crashkernel_after_update
		fi
		;;
	reset-crashkernel-for-installed_kernel)
		if [[ $(kdump_get_conf_val auto_reset_crashkernel) != no ]]; then
			reset_crashkernel_for_installed_kernel "$2"
		fi
		;;
	*)
		dinfo $"Usage: $0 {estimate|start|stop|status|restart|reload|rebuild|reset-crashkernel|propagate|showmem}"
		exit 1
		;;
	esac
}

# Other kdumpctl instances will block in queue, until this one exits
single_instance_lock

# To avoid fd 9 leaking, we invoke a subshell, close fd 9 and call main.
# So that fd isn't leaking when main is invoking a subshell.
(
	exec 9<&-
	main "$@"
)