Mini Shell

#!/usr/bin/bash --norc
# New mkdumprd
#
# Copyright 2011 Red Hat, Inc.
#
# Written by Cong Wang <amwang@redhat.com>
#

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
export IN_KDUMP=1

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

SSH_KEY_LOCATION="/root/.ssh/kdump_id_rsa"
SAVE_PATH=$(get_save_path)
OVERRIDE_RESETTABLE=0

extra_modules=""
dracut_args=(--add kdumpbase --quiet --hostonly --hostonly-cmdline --hostonly-i18n --hostonly-mode strict --hostonly-nics '' -o "plymouth resume ifcfg earlykdump")

MKDUMPRD_TMPDIR="$(mktemp -d -t mkdumprd.XXXXXX)"
[ -d "$MKDUMPRD_TMPDIR" ] || perror_exit "dracut: mktemp -p -d -t dracut.XXXXXX failed."
MKDUMPRD_TMPMNT="$MKDUMPRD_TMPDIR/target"

trap '
    ret=$?;
    is_mounted $MKDUMPRD_TMPMNT && umount -f $MKDUMPRD_TMPMNT;
    [[ -d $MKDUMPRD_TMPDIR ]] && rm --one-file-system -rf -- "$MKDUMPRD_TMPDIR";
    exit $ret;
    ' EXIT

# clean up after ourselves no matter how we die.
trap 'exit 1;' SIGINT

add_dracut_arg()
{
	dracut_args+=("$@")
}

add_dracut_mount()
{
	add_dracut_arg "--mount" "$1"
}

add_dracut_sshkey()
{
	add_dracut_arg "--sshkey" "$1"
}

# caller should ensure $1 is valid and mounted in 1st kernel
to_mount()
{
	local _target=$1 _fstype=$2 _options=$3 _sed_cmd _new_mntpoint _pdev

	_new_mntpoint=$(get_kdump_mntpoint_from_target "$_target")
	_fstype="${_fstype:-$(get_fs_type_from_target "$_target")}"
	_options="${_options:-$(get_mntopt_from_target "$_target")}"
	_options="${_options:-defaults}"

	if [[ $_fstype == "nfs"* ]]; then
		_pdev=$_target
		_sed_cmd+='s/,\(mount\)\?addr=[^,]*//g;'
		_sed_cmd+='s/,\(mount\)\?proto=[^,]*//g;'
		_sed_cmd+='s/,clientaddr=[^,]*//;'
	else
		# for non-nfs _target converting to use udev persistent name
		_pdev="$(kdump_get_persistent_dev "$_target")"
		if [[ -z $_pdev ]]; then
			return 1
		fi
	fi

	# mount fs target as rw in 2nd kernel
	_sed_cmd+='s/\(^\|,\)ro\($\|,\)/\1rw\2/g;'
	# with 'noauto' in fstab nfs and non-root disk mount will fail in 2nd
	# kernel, filter it out here.
	_sed_cmd+='s/\(^\|,\)noauto\($\|,\)/\1/g;'
	# drop nofail or nobootwait
	_sed_cmd+='s/\(^\|,\)nofail\($\|,\)/\1/g;'
	_sed_cmd+='s/\(^\|,\)nobootwait\($\|,\)/\1/g;'

	_options=$(echo "$_options" | sed "$_sed_cmd")

	echo "$_pdev $_new_mntpoint $_fstype $_options"
}

#Function: get_ssh_size
#$1=dump target
#called from while loop and shouldn't read from stdin, so we're using "ssh -n"
get_ssh_size()
{
	local _out
	local _opt=("-i" "$SSH_KEY_LOCATION" "-o" "BatchMode=yes" "-o" "StrictHostKeyChecking=yes")

	if ! _out=$(ssh -q -n "${_opt[@]}" "$1" "df" "--output=avail" "$SAVE_PATH"); then
		perror_exit "checking remote ssh server available size failed."
	fi

	echo -n "$_out" | tail -1
}

#mkdir if save path does not exist on ssh dump target
#$1=ssh dump target
#caller should ensure write permission on $1:$SAVE_PATH
#called from while loop and shouldn't read from stdin, so we're using "ssh -n"
mkdir_save_path_ssh()
{
	local _opt _dir
	_opt=(-i "$SSH_KEY_LOCATION" -o BatchMode=yes -o StrictHostKeyChecking=yes)
	ssh -qn "${_opt[@]}" "$1" mkdir -p "$SAVE_PATH" &> /dev/null ||
		perror_exit "mkdir failed on $1:$SAVE_PATH"

	# check whether user has write permission on $1:$SAVE_PATH
	_dir=$(ssh -qn "${_opt[@]}" "$1" mktemp -dqp "$SAVE_PATH" 2> /dev/null) ||
		perror_exit "Could not create temporary directory on $1:$SAVE_PATH. Make sure user has write permission on destination"
	ssh -qn "${_opt[@]}" "$1" rmdir "$_dir"

	return 0
}

#Function: get_fs_size
#$1=dump target
get_fs_size()
{
	df --output=avail "$(get_mntpoint_from_target "$1")/$SAVE_PATH" | tail -1
}

#Function: get_raw_size
#$1=dump target
get_raw_size()
{
	fdisk -s "$1"
}

#Function: check_size
#$1: dump type string ('raw', 'fs', 'ssh')
#$2: dump target
check_size()
{
	local avail memtotal

	memtotal=$(awk '/MemTotal/{print $2}' /proc/meminfo)
	case "$1" in
	raw)
		avail=$(get_raw_size "$2")
		;;
	ssh)
		avail=$(get_ssh_size "$2")
		;;
	fs)
		avail=$(get_fs_size "$2")
		;;
	*)
		return
		;;
	esac || perror_exit "Check dump target size failed"

	if [[ $avail -lt $memtotal ]]; then
		dwarn "Warning: There might not be enough space to save a vmcore."
		dwarn "         The size of $2 should be greater than $memtotal kilo bytes."
	fi
}

check_save_path_fs()
{
	local _path=$1

	if [[ ! -d $_path ]]; then
		perror_exit "Dump path $_path does not exist."
	fi
}

mount_failure()
{
	local _target=$1
	local _mnt=$2
	local _fstype=$3
	local msg="Failed to mount $_target"

	if [[ -n $_mnt ]]; then
		msg="$msg on $_mnt"
	fi

	msg="$msg for kdump preflight check."

	if [[ $_fstype == "nfs" ]]; then
		msg="$msg Please make sure nfs-utils has been installed."
	fi

	perror_exit "$msg"
}

check_user_configured_target()
{
	local _target=$1 _cfg_fs_type=$2 _mounted
	local _mnt _opt _fstype

	_mnt=$(get_mntpoint_from_target "$_target")
	_opt=$(get_mntopt_from_target "$_target")
	_fstype=$(get_fs_type_from_target "$_target")

	if [[ -n $_fstype ]]; then
		# In case of nfs4, nfs should be used instead, nfs* options is deprecated in kdump.conf
		[[ $_fstype == "nfs"* ]] && _fstype=nfs

		if [[ -n $_cfg_fs_type ]] && [[ $_fstype != "$_cfg_fs_type" ]]; then
			perror_exit "\"$_target\" have a wrong type config \"$_cfg_fs_type\", expected \"$_fstype\""
		fi
	else
		_fstype="$_cfg_fs_type"
		_fstype="$_cfg_fs_type"
	fi

	# For noauto mount, mount it inplace with default value.
	# Else use the temporary target directory
	if [[ -n $_mnt ]]; then
		if ! is_mounted "$_mnt"; then
			if [[ $_opt == *",noauto"* ]]; then
				mount "$_mnt" || mount_failure "$_target" "$_mnt" "$_fstype"
				_mounted=$_mnt
			else
				perror_exit "Dump target \"$_target\" is neither mounted nor configured as \"noauto\""
			fi
		fi
	else
		_mnt=$MKDUMPRD_TMPMNT
		mkdir -p "$_mnt"
		mount "$_target" "$_mnt" -t "$_fstype" -o defaults || mount_failure "$_target" "" "$_fstype"
		_mounted=$_mnt
	fi

	# For user configured target, use $SAVE_PATH as the dump path within the target
	if [[ ! -d "$_mnt/$SAVE_PATH" ]]; then
		perror_exit "Dump path \"$SAVE_PATH\" does not exist in dump target \"$_target\""
	fi

	check_size fs "$_target"

	# Unmount it early, if function is interrupted and didn't reach here, the shell trap will clear it up anyway
	if [[ -n $_mounted ]]; then
		umount -f -- "$_mounted"
	fi
}

# $1: core_collector config value
verify_core_collector()
{
	local _cmd="${1%% *}"
	local _params="${1#${_cmd}}"

	if [[ $_cmd != "makedumpfile" ]]; then
		if is_raw_dump_target; then
			dwarn "Warning: specifying a non-makedumpfile core collector, you will have to recover the vmcore manually."
		fi
		return
	fi

	if is_ssh_dump_target || is_raw_dump_target; then
		if ! strstr "$_params" "-F"; then
			perror_exit 'The specified dump target needs makedumpfile "-F" option.'
		fi
		_params="$_params vmcore"
	else
		_params="$_params vmcore dumpfile"
	fi

	# shellcheck disable=SC2086
	if ! $_cmd --check-params $_params; then
		perror_exit "makedumpfile parameter check failed."
	fi
}

add_mount()
{
	local _mnt

	_mnt=$(to_mount "$@") || exit 1

	add_dracut_mount "$_mnt"
}

#handle the case user does not specify the dump target explicitly
handle_default_dump_target()
{
	local _target
	local _mntpoint

	is_user_configured_dump_target && return

	check_save_path_fs "$SAVE_PATH"

	_save_path=$(get_bind_mount_source "$SAVE_PATH")
	_target=$(get_target_from_path "$_save_path")
	_mntpoint=$(get_mntpoint_from_target "$_target")

	SAVE_PATH=${_save_path##"$_mntpoint"}
	add_mount "$_target"
	check_size fs "$_target"
}

# $1: function name
for_each_block_target()
{
	local dev majmin

	for dev in $(get_kdump_targets); do
		[[ -b $dev ]] || continue
		majmin=$(get_maj_min "$dev")
		check_block_and_slaves "$1" "$majmin" && return 1
	done

	return 0
}

#judge if a specific device with $1 is unresettable
#return false if unresettable.
is_unresettable()
{
	local path device resettable=1

	path="/sys/$(udevadm info --query=all --path="/sys/dev/block/$1" | awk '/^P:/ {print $2}' | sed -e 's/\(cciss[0-9]\+\/\).*/\1/g' -e 's/\/block\/.*$//')/resettable"
	if [[ -f $path ]]; then
		resettable="$(< "$path")"
		[[ $resettable -eq 0 ]] && [[ $OVERRIDE_RESETTABLE -eq 0 ]] && {
			device=$(udevadm info --query=all --path="/sys/dev/block/$1" | awk -F= '/DEVNAME/{print $2}')
			derror "Error: Can not save vmcore because device $device is unresettable"
			return 0
		}
	fi

	return 1
}

#check if machine is resettable.
#return true if resettable
check_resettable()
{
	local _target _override_resettable

	_override_resettable=$(kdump_get_conf_val override_resettable)
	OVERRIDE_RESETTABLE=${_override_resettable:-$OVERRIDE_RESETTABLE}
	if [ "$OVERRIDE_RESETTABLE" != "0" ] && [ "$OVERRIDE_RESETTABLE" != "1" ]; then
		perror_exit "override_resettable value '$OVERRIDE_RESETTABLE' is invalid"
	fi

	for_each_block_target is_unresettable && return

	return 1
}

check_crypt()
{
	local _dev

	for _dev in $(get_kdump_targets); do
		if [[ -n $(get_luks_crypt_dev "$(get_maj_min "$_dev")") ]]; then
			derror "Device $_dev is encrypted." && return 1
		fi
	done
}

if ! check_resettable; then
	exit 1
fi

if ! check_crypt; then
	dwarn "Warning: Encrypted device is in dump path, which is not recommended, see kexec-kdump-howto.txt for more details."
fi

# firstly get right SSH_KEY_LOCATION
keyfile=$(kdump_get_conf_val sshkey)
if [[ -f $keyfile ]]; then
	# canonicalize the path
	SSH_KEY_LOCATION=$(/usr/bin/readlink -m "$keyfile")
fi

while read -r config_opt config_val; do
	# remove inline comments after the end of a directive.
	case "$config_opt" in
	extra_modules)
		extra_modules="$extra_modules $config_val"
		;;
	ext[234] | xfs | btrfs | minix | nfs | virtiofs)
		check_user_configured_target "$config_val" "$config_opt"
		add_mount "$config_val" "$config_opt"
		;;
	raw)
		# checking raw disk writable
		dd if="$config_val" count=1 of=/dev/null > /dev/null 2>&1 || {
			perror_exit "Bad raw disk $config_val"
		}
		_praw=$(persistent_policy="by-id" kdump_get_persistent_dev "$config_val")
		if [[ -z $_praw ]]; then
			exit 1
		fi
		add_dracut_arg "--device" "$_praw"
		check_size raw "$config_val"
		;;
	ssh)
		if strstr "$config_val" "@"; then
			mkdir_save_path_ssh "$config_val"
			check_size ssh "$config_val"
			add_dracut_sshkey "$SSH_KEY_LOCATION"
		else
			perror_exit "Bad ssh dump target $config_val"
		fi
		;;
	core_collector)
		verify_core_collector "$config_val"
		;;
	dracut_args)

		# When users specify nfs dumping via dracut_args, kexec-tools won't
		# mount nfs fs beforehand thus nfsv4-related drivers won't be installed
		# because we call dracut with --hostonly-mode strict. So manually install
		# nfsv4-related drivers.
		if [[ $(get_dracut_args_fstype "$config_val") == nfs* ]]; then
			add_dracut_arg "--add-drivers" nfs_layout_nfsv41_files
		fi

		while read -r dracut_arg; do
			add_dracut_arg "$dracut_arg"
		done <<< "$(echo "$config_val" | xargs -n 1 echo)"
		;;
	*) ;;

	esac
done <<< "$(kdump_read_conf)"

handle_default_dump_target

if ! have_compression_in_dracut_args; then
	if is_squash_available && dracut_have_option "--squash-compressor"; then
		add_dracut_arg "--squash-compressor" "zstd"
	elif is_zstd_command_available; then
		add_dracut_arg "--compress" "zstd"
	fi
fi

if [[ -n $extra_modules ]]; then
	add_dracut_arg "--add-drivers" "$extra_modules"
fi

# TODO: The below check is not needed anymore with the introduction of
#       'zz-fadumpinit' module, that isolates fadump's capture kernel initrd,
#       but still sysroot.mount unit gets generated based on 'root=' kernel
#       parameter available in fadump case. So, find a way to fix that first
#       before removing this check.
if ! is_fadump_capable; then
	# The 2nd rootfs mount stays behind the normal dump target mount,
	# so it doesn't affect the logic of check_dump_fs_modified().
	is_dump_to_rootfs && add_mount "$(to_dev_name "$(get_root_fs_device)")"

	add_dracut_arg "--no-hostonly-default-device"

	if fips-mode-setup --is-enabled 2> /dev/null; then
		add_dracut_arg --add-device "$(findmnt -n -o SOURCE --target /boot)"
	fi
fi

# This is RHEL-only to work around nvme problem, then real fix should go to dracut
if [[ -d /sys/module/nvme ]]; then
	add_dracut_arg "--add-drivers" "nvme"
fi

dracut "${dracut_args[@]}" "$@"

_rc=$?
sync
exit $_rc