#! /bin/bash
#
# storage-fixup			- Tejun Heo <teheo@suse.de>
#
# Script to issue fix up commands for weird disks.  This is primarily
# to adjust ATA APM setting.  Some laptop BIOSen set this value too
# aggressively causing frequent head unloads which can kill the drive
# quickly.  This script should be called during boot and resume.  It
# examines rules from /etc/stroage-fixup.conf and executes matching
# commands.
#
# In stroage-fixup.conf, empty lines and lines starting w/ # are
# ignored.  Each line starts with rule, dmi, hal or act.
#
# rule RULENAME
#	Starts a rule.  $RULENAME can't contain whitespaces.
#
# dmi KEY VALUE
#	Checks whether DMI value for KEY matches VALUE.  If not, the
#	rule is skipped.
#
# hal KEY VALUE
#	Checks whether there are devices which has KEY value matching
#	VALUE.  storage-fixup determines applies actions to devices
#	which match all hal matches, so all rules should have at least
#	one hal match.
#
# act ACTION
#	Executes ACTION on matched devices.  ACTION can contain $DEV
#	which will be substituted with device file of matching device.
#
# For example, the following (useless) rule disables APM on the first
# harddrive of my machine.
#
# rule p5w64
# dmi baseboard-product-name	P5W64 WS Pro
# dmi baseboard-manufacturer	ASUSTeK Computer INC.
# hal storage.model		WDC WD5000YS-01M
# hal storage.serial		SATA_WDC_WD5000YS-01_WD-WMANU1217262
# act hdparm -B 255 $DEV
#

conf_file=${CONF_FILE:-/etc/storage-fixup.conf}
hal_find_by_property=${HAL_FIND_BY_PROPERTY:-hal-find-by-property}
hal_get_property=${HAL_GET_PROPERTY:-hal-get-property}
dmidecode=${DMIDECODE:-dmidecode}

verbose=0
lineno=0
skip=0
rule_name=""
declare -a dev_ids
newline=$'\n'

log() {
    echo "storage-fixup: $@"
}

warn() {
   log "$@" 1>&2
}

debug() {
    if [ $verbose -ne 0 ]; then
	warn "$@"
    fi
}

#
# Match functions - do_dmi() and do_hal() - execute DMI and HAL
# matches respectively.  Return value 0 indicates match, 1 invalid
# match (triggers warning) and 2 mismatch.
#
do_dmi() {
    local val

    if [ -z "$1" -o -z "$2" ]; then
	return 1
    fi

    val=$($dmidecode --string "$1")
    if [ "$?" -ne 0 ]; then
	return 1
    fi

    if [ "$val" = "$2" ]; then
	debug "Y $lineno $rule_name dmi $1=$2"
	return 0;
    fi

    debug "N $lineno $rule_name dmi $1=$2"
    return 2
}

do_hal() {
    local i out ifs_store append=0

    if [ -z "$1" -o -z "$2" ]; then
	return 1
    fi

    if [ ${#dev_ids[@]} -eq 0 ]; then
	append=1
    fi

    #
    # bash really isn't a good programming language for this kind of
    # stuff and makes it look much more complex than it needs to be.
    # The following loop executes hal-find-by-property and ands the
    # result with the previous result.
    #
    ifs_store="$IFS"
    IFS="$newline"
    dev_ids=(
	$($hal_find_by_property --key "$1" --string "$2" \
	    | while read found; do
		if [ $append -ne 0 ]; then
		    echo "$found"
		else
		    for id in "${dev_ids[@]}"; do
			if [ "$id" = "$found" ]; then
			    echo "$found"
			    break
			fi
		    done
		fi
	    done))
    IFS="$ifs_store"

    if [ "$?" -ne 0 ]; then
	debug "N $lineno $rule_name hal $1=$2"
	return 2
    fi

    debug "Y $lineno $rule_name hal nr_devs=${#dev_ids[@]} $1=$2"

    return 0
}

do_act() {
    local id dev

    for id in "${dev_ids[@]}"; do
	if ! DEV=$($hal_get_property --udi "$id" --key block.device); then
	    warn "can't find device node for $id"
	    continue
	fi

	eval log "$rule_name: executing \"$1\""
	eval "$1"
    done

    return 0
}

while read f0 f1 f2; do
    true $((lineno++))
    if [ -z ${f0###*} ]; then
	continue
    fi

    if [ "$f0" = rule ]; then
	rule_name=$f1
	skip=0
	dev_ids=()
	continue
    fi

    if [ $skip -ne 0 ]; then
	continue
    fi

    case "$f0" in
    dmi)
	    do_dmi "$f1" "$f2"
	    ;;
    hal)
	    do_hal "$f1" "$f2"
	    ;;
    act)
	    do_act "$f1 $f2"
	    ;;
    *)
	    false
	    ;;
    esac

    ret=$?
    if [ $ret -ne 0 ]; then
	if [ $ret -eq 1 ]; then
	    warn "malformed line $lineno \"$f0 $f1 $f2\","\
	         "skipping rule $rule_name" 2>&1
	fi
	skip=1
    fi
done < $conf_file