#! /bin/bash -eu

# Script for checking various microcode caveats
#
#
# SPDX-License-Identifier: CC0-1.0

: ${MC_CAVEATS_DATA_DIR=/usr/share/microcode_ctl/ucode_with_caveats}

usage() {
	echo 'Usage: check_caveats [-k TARGET_KVER] [-c CONFIG] [-m] [-v]'
	echo
	echo '   -k - target version to check against, $(uname -r) is used'
	echo '        otherwise'
	echo '   -c - caveat config(s) to check, all configs are checked'
	echo '        otherwise'
	echo '   -m - check that caveats actually apply to the current model'
	echo '   -v - verbose output'
	echo
	echo 'Environment:'
	echo '  MC_CAVEATS_DATA_DIR - directory that contains caveats'
	echo '                        configuration data'
}

debug() { [ 0 = "$verbose" ] || echo "$*" >&2; }

# A simplified RPM version comparison that takes into account knowledge about
# Y- and Z-streams (so it compares versions inside Y-stram or Z-stream if
# the version against which comparison is performed has appropriate versioning
# scheme).
#
# $1 - kernel version to check
# $* - list of kernel versions to check against
check_kver()
{
	local t_major= t_minor= t_patch= t_y= t_z1= t_z2= t_rest=
	local m_major= m_minor= m_patch= m_y= m_z1= m_z2= m_rest=
	local cmp_type=

	# IFS=.- read -r t_major t_minor t_patch t_y t_z1 t_z2 t_rest <<<"$1"
	# "cannot create temp file for here-document: Read-only file system"
	# that's why we can't have nice things.
	t_major=${1%%[.-]*}
	t_rest=${1#${t_major}}
	t_rest=${t_rest#[.-]}
	t_minor=${t_rest%%[.-]*}
	t_rest=${t_rest#${t_minor}}
	t_rest=${t_rest#[.-]}
	t_patch=${t_rest%%[.-]*}
	t_rest=${t_rest#${t_patch}}
	t_rest=${t_rest#[.-]}
	t_y=${t_rest%%[.-]*}
	t_rest=${t_rest#${t_y}}
	t_rest=${t_rest#[.-]}
	t_z1=${t_rest%%[.-]*}
	t_rest=${t_rest#${t_z1}}
	t_rest=${t_rest#[.-]}
	t_z2=${t_rest%%[.-]*}

	# minor/major/patch/y should be numeric
	[ -n "${t_major##*[!0-9]*}" ] || return 1
	[ -n "${t_minor##*[!0-9]*}" ] || return 1
	[ -n "${t_patch##*[!0-9]*}" ] || return 1
	[ -n "${t_y##*[!0-9]*}" ] || return 1
	# reset z1/z2 to zero if non-numeric
	[ -n "${t_z1##*[!0-9]*}" ] || t_z1=0
	[ -n "${t_z2##*[!0-9]*}" ] || t_z2=0

	while [ 1 -lt "$#" ]; do
		cmp_type=upstream

		shift
		m_major=${1%%[.-]*}
		m_rest=${1#${m_major}}
		m_rest=${m_rest#[.-]}
		m_minor=${m_rest%%[.-]*}
		m_rest=${m_rest#${m_minor}}
		m_rest=${m_rest#[.-]}
		m_patch=${m_rest%%[.-]*}
		m_rest=${m_rest#${m_patch}}
		m_rest=${m_rest#[.-]}
		m_y=${m_rest%%[.-]*}
		m_rest=${m_rest#${m_y}}
		m_rest=${m_rest#[.-]}
		m_z1=${m_rest%%[.-]*}
		m_rest=${m_rest#${m_z1}}
		m_rest=${m_rest#[.-]}
		m_z2=${m_rest%%[.-]*}

		# minor/major/patch should be numeric
		[ -n "${m_major##*[!0-9]*}" ] || continue
		[ -n "${m_minor##*[!0-9]*}" ] || continue
		[ -n "${m_patch##*[!0-9]*}" ] || continue
		# reset z1/z2 to zero if non-numeric
		[ -n "${m_y##*[!0-9]*}" ] && cmp_type=y || m_y=0
		[ -n "${m_z1##*[!0-9]*}" ] && cmp_type=z || m_z1=0
		[ -n "${m_z2##*[!0-9]*}" ] && cmp_type=z || m_z2=0

		# Comparing versions
		case "$cmp_type" in
		upstream)
			[ "$t_major" -ge "$m_major" ] || continue
			[ "$t_minor" -ge "$m_minor" ] || continue
			[ "$t_patch" -ge "$m_patch" ] || continue
			return 0
			;;
		y)
			[ "$t_major" -eq "$m_major" ] || continue
			[ "$t_minor" -eq "$m_minor" ] || continue
			[ "$t_patch" -eq "$m_patch" ] || continue
			[ "$t_y" -ge "$m_y" ] || continue
			return 0
			;;
		z)
			[ "$t_major" -eq "$m_major" ] || continue
			[ "$t_minor" -eq "$m_minor" ] || continue
			[ "$t_patch" -eq "$m_patch" ] || continue
			[ "$t_y" -eq "$m_y" ] || continue
			[ "$t_z1" -ge "$m_z1" ] || continue
			[ "$t_z2" -ge "$m_z2" ] || continue
			return 0
			;;
		esac
	done

	return 1
}

# Provides model in format "VENDOR_ID FAMILY-MODEL-STEPPING"
#
# We check only the first processor as we don't expect non-symmetrical setups
# with CPUs with caveats
get_model_string()
{
	/usr/bin/printf "%s %02x-%02x-%02x" \
		$(/bin/sed -rn '1,/^$/{
			s/^vendor_id[[:space:]]*: (.*)$/\1/p;
			s/^cpu family[[:space:]]*: (.*)$/\1/p;
			s/^model[[:space:]]*: (.*)$/\1/p;
			s/^stepping[[:space:]]*: (.*)$/\1/p;
		}' /proc/cpuinfo)
}

get_model_name()
{
	/bin/sed -rn '1,/^$/s/^model name[[:space:]]*: (.*)$/\1/p' /proc/cpuinfo
}

#check_kver "$@"
#get_model_name

match_model=0
configs=
kver=$(/bin/uname -r)
verbose=0

while getopts "k:c:mv" opt; do
	case "${opt}" in
	k)
		kver="$OPTARG"
		;;
	c)
		configs="$configs $OPTARG"
		;;
	m)
		match_model=1
		;;
	v)
		verbose=1
		;;
	*)
		usage
		exit 1;
		;;
	esac
done

: ${configs:=$(find "${MC_CAVEATS_DATA_DIR}" -maxdepth 1 -mindepth 1 -type d -printf "%f\n")}

cpu_model=$(get_model_string)
cpu_model_name=$(get_model_name)

for cfg in $(echo "${configs}"); do
	dir="$MC_CAVEATS_DATA_DIR/$cfg"
	[ -r "${dir}/config" ] || {
		debug "File 'config' in ${dir} is not found, skipping"
		continue
	}

	cfg_model=
	cfg_path=
	cfg_kvers=
	cfg_blacklist=

	while read -r key value; do
		case "$key" in
		model)
			cfg_model="$value"
			;;
		path)
			cfg_path="$cfg_path $value"
			;;
		kernel)
			cfg_kvers="$cfg_kvers $value"
			;;
		blacklist)
			cfg_blacklist=1
			break
			;;
		esac
	done < "${dir}/config"

	[ -z "${cfg_blacklist}" ] || \
		cfg_blacklist=$(/bin/sed -n '/^blacklist$/,$p' "${dir}/config" |
					/usr/bin/tail -n +2)

	debug "${cfg}: model '$cfg_model', path '$cfg_path', kvers '$cfg_kvers'"
	debug "${cfg}: blacklist '$cfg_blacklist'"

	if [ -n "$cfg_model" ]; then
		[ 0 -eq "$match_model" ] || {
			[ "x$cpu_model" = "x$cfg_model" ] || {
				debug "Current CPU model '$cpu_model' doesn't" \
				      "match config CPU model '$cfg_model'," \
				      "skipping"
				continue
			}
		}
	fi

	if [ -n "$cfg_kvers" ]; then
		check_kver "$kver" $cfg_kvers || {
			debug "${cfg}: kernel version check for '$kver'" \
			      "against '$cfg_kvers' failed"
			exit 1
		}
	fi

	if [ -n "$cfg_blacklist" ]; then
		echo "$cfg_blacklist" | /bin/grep -vqFx "${cpu_model_name}" || {
			debug "${cfg}: model '${cpu_model_name}' is blacklisted"
			exit 1
		}
	fi

	#printf "%s " "$cfg"
	#[ 0 -eq "$match_model" ] || printf "%s " "$cpu_model"
	echo $cfg_path
done

exit 0