Mini Shell

#!/usr/bin/sh
#
# The main kdump routine in capture kernel, bash may not be the
# default shell. Any code added must be POSIX compliant.

. /lib/dracut-lib.sh
. /lib/kdump-logger.sh
. /lib/kdump-lib-initramfs.sh

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

KDUMP_PATH="/var/crash"
KDUMP_LOG_FILE="/run/initramfs/kexec-dmesg.log"
CORE_COLLECTOR=""
DEFAULT_CORE_COLLECTOR="makedumpfile -l --message-level 7 -d 31"
DMESG_COLLECTOR="/sbin/vmcore-dmesg"
FAILURE_ACTION="systemctl reboot -f"
DATEDIR=$(date +%Y-%m-%d-%T)
HOST_IP='127.0.0.1'
DUMP_INSTRUCTION=""
SSH_KEY_LOCATION="/root/.ssh/kdump_id_rsa"
DD_BLKSIZE=512
FINAL_ACTION="systemctl reboot -f"
KDUMP_PRE=""
KDUMP_POST=""
NEWROOT="/sysroot"
OPALCORE="/sys/firmware/opal/mpipl/core"
KDUMP_CONF_PARSED="/tmp/kdump.conf.$$"

# POSIX doesn't have pipefail, only apply when using bash
# shellcheck disable=SC3040
[ -n "$BASH" ] && set -o pipefail

DUMP_RETVAL=0

kdump_read_conf > $KDUMP_CONF_PARSED

get_kdump_confs()
{
	while read -r config_opt config_val; do
		# remove inline comments after the end of a directive.
		case "$config_opt" in
		path)
			KDUMP_PATH="$config_val"
			;;
		core_collector)
			[ -n "$config_val" ] && CORE_COLLECTOR="$config_val"
			;;
		sshkey)
			if [ -f "$config_val" ]; then
				SSH_KEY_LOCATION=$config_val
			fi
			;;
		kdump_pre)
			KDUMP_PRE="$config_val"
			;;
		kdump_post)
			KDUMP_POST="$config_val"
			;;
		fence_kdump_args)
			FENCE_KDUMP_ARGS="$config_val"
			;;
		fence_kdump_nodes)
			FENCE_KDUMP_NODES="$config_val"
			;;
		failure_action | default)
			case $config_val in
			shell)
				FAILURE_ACTION="kdump_emergency_shell"
				;;
			reboot)
				FAILURE_ACTION="systemctl reboot -f && exit"
				;;
			halt)
				FAILURE_ACTION="halt && exit"
				;;
			poweroff)
				FAILURE_ACTION="systemctl poweroff -f && exit"
				;;
			dump_to_rootfs)
				FAILURE_ACTION="dump_to_rootfs"
				;;
			esac
			;;
		final_action)
			case $config_val in
			reboot)
				FINAL_ACTION="systemctl reboot -f"
				;;
			halt)
				FINAL_ACTION="halt"
				;;
			poweroff)
				FINAL_ACTION="systemctl poweroff -f"
				;;
			esac
			;;
		esac
	done < "$KDUMP_CONF_PARSED"

	if [ -z "$CORE_COLLECTOR" ]; then
		CORE_COLLECTOR="$DEFAULT_CORE_COLLECTOR"
		if is_ssh_dump_target || is_raw_dump_target; then
			CORE_COLLECTOR="$CORE_COLLECTOR -F"
		fi
	fi
}

# store the kexec kernel log to a file.
save_log()
{
	dmesg -T > $KDUMP_LOG_FILE

	if command -v journalctl > /dev/null; then
		journalctl -ab >> $KDUMP_LOG_FILE
	fi
	chmod 600 $KDUMP_LOG_FILE
}

# $1: dump path, must be a mount point
dump_fs()
{
	ddebug "dump_fs _mp=$1"

	if ! is_mounted "$1"; then
		dinfo "dump path '$1' is not mounted, trying to mount..."
		if ! mount --target "$1"; then
			derror "failed to dump to '$1', it's not a mount point!"
			return 1
		fi
	fi

	# Remove -F in makedumpfile case. We don't want a flat format dump here.
	case $CORE_COLLECTOR in
	*makedumpfile*)
		CORE_COLLECTOR=$(echo "$CORE_COLLECTOR" | sed -e "s/-F//g")
		;;
	esac

	_dump_fs_path=$(echo "$1/$KDUMP_PATH/$HOST_IP-$DATEDIR/" | tr -s /)
	dinfo "saving to $_dump_fs_path"

	# Only remount to read-write mode if the dump target is mounted read-only.
	_dump_mnt_op=$(get_mount_info OPTIONS target "$1" -f)
	case $_dump_mnt_op in
	ro*)
		dinfo "Remounting the dump target in rw mode."
		mount -o remount,rw "$1" || return 1
		;;
	esac

	mkdir -p "$_dump_fs_path" || return 1

	save_vmcore_dmesg_fs ${DMESG_COLLECTOR} "$_dump_fs_path"
	save_opalcore_fs "$_dump_fs_path"

	dinfo "saving vmcore"
	$CORE_COLLECTOR /proc/vmcore "$_dump_fs_path/vmcore-incomplete"
	_dump_exitcode=$?
	if [ $_dump_exitcode -eq 0 ]; then
		sync -f "$_dump_fs_path/vmcore-incomplete"
		_sync_exitcode=$?
		if [ $_sync_exitcode -eq 0 ]; then
			mv "$_dump_fs_path/vmcore-incomplete" "$_dump_fs_path/vmcore"
			dinfo "saving vmcore complete"
		else
			derror "sync vmcore failed, exitcode:$_sync_exitcode"
			return 1
		fi
	else
		derror "saving vmcore failed, exitcode:$_dump_exitcode"
	fi

	dinfo "saving the $KDUMP_LOG_FILE to $_dump_fs_path/"
	save_log
	mv "$KDUMP_LOG_FILE" "$_dump_fs_path/"
	if [ $_dump_exitcode -ne 0 ]; then
		return 1
	fi

	# improper kernel cmdline can cause the failure of echo, we can ignore this kind of failure
	return 0
}

# $1: dmesg collector
# $2: dump path
save_vmcore_dmesg_fs()
{
	dinfo "saving vmcore-dmesg.txt to $2"
	if $1 /proc/vmcore > "$2/vmcore-dmesg-incomplete.txt"; then
		mv "$2/vmcore-dmesg-incomplete.txt" "$2/vmcore-dmesg.txt"
		chmod 600 "$2/vmcore-dmesg.txt"

		# Make sure file is on disk. There have been instances where later
		# saving vmcore failed and system rebooted without sync and there
		# was no vmcore-dmesg.txt available.
		sync
		dinfo "saving vmcore-dmesg.txt complete"
	else
		if [ -f "$2/vmcore-dmesg-incomplete.txt" ]; then
			chmod 600 "$2/vmcore-dmesg-incomplete.txt"
		fi
		derror "saving vmcore-dmesg.txt failed"
	fi
}

# $1: dump path
save_opalcore_fs()
{
	if [ ! -f $OPALCORE ]; then
		# Check if we are on an old kernel that uses a different path
		if [ -f /sys/firmware/opal/core ]; then
			OPALCORE="/sys/firmware/opal/core"
		else
			return 0
		fi
	fi

	dinfo "saving opalcore:$OPALCORE to $1/opalcore"
	if ! cp $OPALCORE "$1/opalcore"; then
		derror "saving opalcore failed"
		return 1
	fi

	sync
	dinfo "saving opalcore complete"
	return 0
}

dump_to_rootfs()
{

	if [ "$(systemctl status dracut-initqueue | sed -n "s/^\s*Active: \(\S*\)\s.*$/\1/p")" = "inactive" ]; then
		dinfo "Trying to bring up initqueue for rootfs mount"
		systemctl start dracut-initqueue
	fi

	dinfo "Clean up dead systemd services"
	systemctl cancel
	dinfo "Waiting for rootfs mount, will timeout after 90 seconds"
	systemctl start --no-block sysroot.mount

	_loop=0
	while [ $_loop -lt 90 ] && ! is_mounted /sysroot; do
		sleep 1
		_loop=$((_loop + 1))
	done

	if ! is_mounted /sysroot; then
		derror "Failed to mount rootfs"
		return
	fi

	ddebug "NEWROOT=$NEWROOT"
	dump_fs $NEWROOT
}

kdump_emergency_shell()
{
	ddebug "Switching to kdump emergency shell..."

	[ -f /etc/profile ] && . /etc/profile
	export PS1='kdump:${PWD}# '

	. /lib/dracut-lib.sh
	if [ -f /dracut-state.sh ]; then
		. /dracut-state.sh 2> /dev/null
	fi

	source_conf /etc/conf.d

	type plymouth > /dev/null 2>&1 && plymouth quit

	source_hook "emergency"
	while read -r _tty rest; do
		(
			echo
			echo
			echo 'Entering kdump emergency mode.'
			echo 'Type "journalctl" to view system logs.'
			echo 'Type "rdsosreport" to generate a sosreport, you can then'
			echo 'save it elsewhere and attach it to a bug report.'
			echo
			echo
		) > "/dev/$_tty"
	done < /proc/consoles
	sh -i -l
	/bin/rm -f -- /.console_lock
}

do_failure_action()
{
	dinfo "Executing failure action $FAILURE_ACTION"
	eval $FAILURE_ACTION
}

do_final_action()
{
	dinfo "Executing final action $FINAL_ACTION"
	eval $FINAL_ACTION
}

do_dump()
{
	eval $DUMP_INSTRUCTION
	_ret=$?

	if [ $_ret -ne 0 ]; then
		derror "saving vmcore failed"
	fi

	return $_ret
}

do_kdump_pre()
{
	if [ -n "$KDUMP_PRE" ]; then
		"$KDUMP_PRE"
		_ret=$?
		if [ $_ret -ne 0 ]; then
			derror "$KDUMP_PRE exited with $_ret status"
			return $_ret
		fi
	fi

	# if any script fails, it just raises warning and continues
	if [ -d /etc/kdump/pre.d ]; then
		for file in /etc/kdump/pre.d/*; do
			"$file"
			_ret=$?
			if [ $_ret -ne 0 ]; then
				derror "$file exited with $_ret status"
			fi
		done
	fi
	return 0
}

do_kdump_post()
{
	if [ -d /etc/kdump/post.d ]; then
		for file in /etc/kdump/post.d/*; do
			"$file" "$1"
			_ret=$?
			if [ $_ret -ne 0 ]; then
				derror "$file exited with $_ret status"
			fi
		done
	fi

	if [ -n "$KDUMP_POST" ]; then
		"$KDUMP_POST" "$1"
		_ret=$?
		if [ $_ret -ne 0 ]; then
			derror "$KDUMP_POST exited with $_ret status"
		fi
	fi
}

# $1: block target, eg. /dev/sda
dump_raw()
{
	[ -b "$1" ] || return 1

	dinfo "saving to raw disk $1"

	if ! echo "$CORE_COLLECTOR" | grep -q makedumpfile; then
		_src_size=$(stat --format %s /proc/vmcore)
		_src_size_mb=$((_src_size / 1048576))
		/kdumpscripts/monitor_dd_progress $_src_size_mb &
	fi

	dinfo "saving vmcore"
	$CORE_COLLECTOR /proc/vmcore | dd of="$1" bs=$DD_BLKSIZE >> /tmp/dd_progress_file 2>&1 || return 1
	sync

	dinfo "saving vmcore complete"
	return 0
}

# $1: ssh key file
# $2: ssh address in <user>@<host> format
dump_ssh()
{
	_ret=0
	_ssh_opt="-i $1 -o BatchMode=yes -o StrictHostKeyChecking=yes"
	_ssh_dir="$KDUMP_PATH/$HOST_IP-$DATEDIR"
	if is_ipv6_address "$2"; then
		_scp_address=${2%@*}@"[${2#*@}]"
	else
		_scp_address=$2
	fi

	dinfo "saving to $2:$_ssh_dir"

	cat /var/lib/random-seed > /dev/urandom
	ssh -q $_ssh_opt "$2" mkdir -p "$_ssh_dir" || return 1

	save_vmcore_dmesg_ssh "$DMESG_COLLECTOR" "$_ssh_dir" "$_ssh_opt" "$2"
	dinfo "saving vmcore"

	save_opalcore_ssh "$_ssh_dir" "$_ssh_opt" "$2" "$_scp_address"

	if [ "${CORE_COLLECTOR%%[[:blank:]]*}" = "scp" ]; then
		scp -q $_ssh_opt /proc/vmcore "$_scp_address:$_ssh_dir/vmcore-incomplete"
		_ret=$?
		_vmcore="vmcore"
	else
		$CORE_COLLECTOR /proc/vmcore | ssh $_ssh_opt "$2" "umask 0077 && dd bs=512 of='$_ssh_dir/vmcore-incomplete'"
		_ret=$?
		_vmcore="vmcore.flat"
	fi

	if [ $_ret -eq 0 ]; then
		ssh $_ssh_opt "$2" "mv '$_ssh_dir/vmcore-incomplete' '$_ssh_dir/$_vmcore'"
		_ret=$?
		if [ $_ret -ne 0 ]; then
			derror "moving vmcore failed, exitcode:$_ret"
		else
			dinfo "saving vmcore complete"
		fi
	else
		derror "saving vmcore failed, exitcode:$_ret"
	fi

	dinfo "saving the $KDUMP_LOG_FILE to $2:$_ssh_dir/"
	save_log
	if ! scp -q $_ssh_opt $KDUMP_LOG_FILE "$_scp_address:$_ssh_dir/"; then
		derror "saving log file failed, _exitcode:$_ret"
	fi

	return $_ret
}

# $1: dump path
# $2: ssh opts
# $3: ssh address in <user>@<host> format
# $4: scp address, similar with ssh address but IPv6 addresses are quoted
save_opalcore_ssh()
{
	if [ ! -f $OPALCORE ]; then
		# Check if we are on an old kernel that uses a different path
		if [ -f /sys/firmware/opal/core ]; then
			OPALCORE="/sys/firmware/opal/core"
		else
			return 0
		fi
	fi

	dinfo "saving opalcore:$OPALCORE to $3:$1"

	if ! scp $2 $OPALCORE "$4:$1/opalcore-incomplete"; then
		derror "saving opalcore failed"
		return 1
	fi

	ssh $2 "$3" mv "$1/opalcore-incomplete" "$1/opalcore"
	dinfo "saving opalcore complete"
	return 0
}

# $1: dmesg collector
# $2: dump path
# $3: ssh opts
# $4: ssh address in <user>@<host> format
save_vmcore_dmesg_ssh()
{
	dinfo "saving vmcore-dmesg.txt to $4:$2"
	if $1 /proc/vmcore | ssh $3 "$4" "umask 0077 && dd of='$2/vmcore-dmesg-incomplete.txt'"; then
		ssh -q $3 "$4" mv "$2/vmcore-dmesg-incomplete.txt" "$2/vmcore-dmesg.txt"
		dinfo "saving vmcore-dmesg.txt complete"
	else
		derror "saving vmcore-dmesg.txt failed"
	fi
}

wait_online_network()
{
	# In some cases, network may still not be ready because nm-online is called
	# with "-s" which means to wait for NetworkManager startup to complete, rather
	# than waiting for network connectivity specifically. Wait 10mins more for the
	# network to be truely ready in these cases.
	_loop=0
	while [ $_loop -lt 600 ]; do
		sleep 1
		_loop=$((_loop + 1))
		if _route=$(kdump_get_ip_route "$1" 2> /dev/null); then
			printf "%s" "$_route"
			return
		else
			dwarn "Waiting for network to be ready (${_loop}s / 10min)"
		fi
	done

	derror "Oops. The network still isn't ready after waiting 10mins."
	exit 1
}

get_host_ip()
{

	if ! is_nfs_dump_target && ! is_ssh_dump_target; then
		return 0
	fi

	_kdump_remote_ip=$(getarg kdump_remote_ip=)

	if [ -z "$_kdump_remote_ip" ]; then
		derror "failed to get remote IP address!"
		return 1
	fi

	if ! _route=$(wait_online_network "$_kdump_remote_ip"); then
		return 1
	fi

	_netdev=$(kdump_get_ip_route_field "$_route" "dev")

	if ! _kdumpip=$(ip addr show dev "$_netdev" | grep '[ ]*inet'); then
		derror "Failed to get IP of $_netdev"
		return 1
	fi

	_kdumpip=$(echo "$_kdumpip" | head -n 1 | awk '{print $2}')
	_kdumpip="${_kdumpip%%/*}"
	HOST_IP=$_kdumpip
}

read_kdump_confs()
{
	if [ ! -f "$KDUMP_CONFIG_FILE" ]; then
		derror "$KDUMP_CONFIG_FILE not found"
		return
	fi

	get_kdump_confs

	# rescan for add code for dump target
	while read -r config_opt config_val; do
		# remove inline comments after the end of a directive.
		case "$config_opt" in
		dracut_args)
			config_val=$(get_dracut_args_target "$config_val")
			if [ -n "$config_val" ]; then
				config_val=$(get_mntpoint_from_target "$config_val")
				DUMP_INSTRUCTION="dump_fs $config_val"
			fi
			;;
		ext[234] | xfs | btrfs | minix | nfs | virtiofs)
			config_val=$(get_mntpoint_from_target "$config_val")
			DUMP_INSTRUCTION="dump_fs $config_val"
			;;
		raw)
			DUMP_INSTRUCTION="dump_raw $config_val"
			;;
		ssh)
			DUMP_INSTRUCTION="dump_ssh $SSH_KEY_LOCATION $config_val"
			;;
		esac
	done < "$KDUMP_CONF_PARSED"
}

fence_kdump_notify()
{
	if [ -n "$FENCE_KDUMP_NODES" ]; then
		# shellcheck disable=SC2086
		$FENCE_KDUMP_SEND $FENCE_KDUMP_ARGS $FENCE_KDUMP_NODES &
	fi
}

if [ "$1" = "--error-handler" ]; then
	get_kdump_confs
	do_failure_action
	do_final_action

	exit $?
fi

# continue here only if we have to save dump.
if [ -f /etc/fadump.initramfs ] && [ ! -f /proc/device-tree/rtas/ibm,kernel-dump ] && [ ! -f /proc/device-tree/ibm,opal/dump/mpipl-boot ]; then
	exit 0
fi

read_kdump_confs
fence_kdump_notify

if ! get_host_ip; then
	derror "get_host_ip exited with non-zero status!"
	exit 1
fi

if [ -z "$DUMP_INSTRUCTION" ]; then
	DUMP_INSTRUCTION="dump_fs $NEWROOT"
fi

if ! do_kdump_pre; then
	derror "kdump_pre script exited with non-zero status!"
	do_final_action
	# During systemd service to reboot the machine, stop this shell script running
	exit 1
fi
make_trace_mem "kdump saving vmcore" '1:shortmem' '2+:mem' '3+:slab'
do_dump
DUMP_RETVAL=$?

if ! do_kdump_post $DUMP_RETVAL; then
	derror "kdump_post script exited with non-zero status!"
fi

if [ $DUMP_RETVAL -ne 0 ]; then
	exit 1
fi

do_final_action