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rule_generator.functions
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rule_generator.functions
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# functions used by the udev rule generator
# Copyright (C) 2006 Marco d'Itri <[email protected]>
# 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'
# 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 $1/.is-writeable
return 0
else
return 1
fi
}
# Create a lock file for the current rules file.
lock_rules_file() {
RUNDIR="/run"
[ -e "$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 $RULES_LOCK || true
}
# Choose the real rules file if it is writeable or a temporary file if not.
# Both files should be checked later when looking for existing rules.
choose_rules_file() {
RUNDIR="/run"
local tmp_rules_file="$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)
}