# functions used by the udev rule generator

# Copyright (C) 2006 Marco d'Itri <md@Linux.IT>

# This program is free software: you can redistribute it and/or modify

# it under the terms of the GNU General Public License as published by

# the Free Software Foundation, either version 2 of the License, or

# (at your option) any later version.

# This program is distributed in the hope that it will be useful,

# but WITHOUT ANY WARRANTY; without even the implied warranty of

# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the

# GNU General Public License for more details.

# You should have received a copy of the GNU General Public License

# along with this program. If not, see <http://www.gnu.org/licenses/>.

PATH='/sbin:/bin'

#

PATH='/sbin:/bin'

# Read a single line from file $1 in the $DEVPATH directory.

# The function must not return an error even if the file does not exist.

sysread() {

local file="$1"

[ -e "/sys$DEVPATH/$file" ] || return 0

local value

read value < "/sys$DEVPATH/$file" || return 0

echo "$value"

}

sysreadlink() {

local file="$1"

[ -e "/sys$DEVPATH/$file" ] || return 0

readlink -f /sys$DEVPATH/$file 2> /dev/null || true

}

# Return true if a directory is writeable.

writeable() {

if ln -s test-link $1/.is-writeable 2> /dev/null; then

rm -f $1/.is-writeable

return 0

else

return 1

fi

}

# Create a lock file for the current rules file.

lock_rules_file() {

RUNDIR=$(udevadm info --run)

[ -e "$RUNDIR" ] || return 0

RULES_LOCK="$RUNDIR/.lock-${RULES_FILE##*/}"

retry=30

while ! mkdir $RULES_LOCK 2> /dev/null; do

if [ $retry -eq 0 ]; then

echo "Cannot lock $RULES_FILE!" >&2

exit 2

fi

sleep 1

retry=$(($retry - 1))

done

}

unlock_rules_file() {

[ "$RULES_LOCK" ] || return 0

rmdir $RULES_LOCK || true

}

# Choose the real rules file if it is writeable or a temporary file if not.

# Both files should be checked later when looking for existing rules.

choose_rules_file() {

RUNDIR=$(udevadm info --run)

local tmp_rules_file="$RUNDIR/tmp-rules--${RULES_FILE##*/}"

[ -e "$RULES_FILE" -o -e "$tmp_rules_file" ] || PRINT_HEADER=1

if writeable ${RULES_FILE%/*}; then

RO_RULES_FILE='/dev/null'

else

RO_RULES_FILE=$RULES_FILE

RULES_FILE=$tmp_rules_file

fi

}

# Return the name of the first free device.

raw_find_next_available() {

local links="$1"

local basename=${links%%[ 0-9]*}

local max=-1

for name in $links; do

local num=${name#$basename}

[ "$num" ] || num=0

[ $num -gt $max ] && max=$num

done

local max=$(($max + 1))

# "name0" actually is just "name"

[ $max -eq 0 ] && return

echo "$max"

}

# Find all rules matching a key (with action) and a pattern.

find_all_rules() {

local key="$1"

local linkre="$2"

local match="$3"

local search='.*[[:space:],]'"$key"'"('"$linkre"')".*'

echo $(sed -n -r -e 's/^#.*//' -e "${match}s/${search}/\1/p" \

$RO_RULES_FILE \

$([ -e $RULES_FILE ] && echo $RULES_FILE) \

2>/dev/null)

}