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99 lines
2.3 KiB
Plaintext
99 lines
2.3 KiB
Plaintext
# functions used by the udev rule generator
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#
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# This program is free software; you can redistribute it and/or modify it
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# under the terms of the GNU General Public License as published by the
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# Free Software Foundation version 2 of the License.
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PATH='/sbin:/bin'
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# Read a single line from file $1 in the $DEVPATH directory.
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# The function must not return an error even if the file does not exist.
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sysread() {
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local file="$1"
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[ -e "/sys$DEVPATH/$file" ] || return 0
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local value
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read value < "/sys$DEVPATH/$file" || return 0
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echo "$value"
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}
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sysreadlink() {
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local file="$1"
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[ -e "/sys$DEVPATH/$file" ] || return 0
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readlink -f /sys$DEVPATH/$file 2> /dev/null || true
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}
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# Return true if a directory is writeable.
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writeable() {
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if ln -s test-link $1/.is-writeable 2> /dev/null; then
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rm -f $1/.is-writeable
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return 0
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else
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return 1
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fi
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}
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# Create a lock file for the current rules file.
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lock_rules_file() {
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[ -e /dev/.udev/ ] || return 0
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RULES_LOCK="/dev/.udev/.lock-${RULES_FILE##*/}"
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retry=30
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while ! mkdir $RULES_LOCK 2> /dev/null; do
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if [ $retry -eq 0 ]; then
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echo "Cannot lock $RULES_FILE!" >&2
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exit 2
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fi
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sleep 1
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retry=$(($retry - 1))
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done
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}
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unlock_rules_file() {
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[ "$RULES_LOCK" ] || return 0
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rmdir $RULES_LOCK || true
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}
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# Choose the real rules file if it is writeable or a temporary file if not.
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# Both files should be checked later when looking for existing rules.
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choose_rules_file() {
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local tmp_rules_file="/dev/.udev/tmp-rules--${RULES_FILE##*/}"
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[ -e "$RULES_FILE" -o -e "$tmp_rules_file" ] || PRINT_HEADER=1
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if writeable ${RULES_FILE%/*}; then
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RO_RULES_FILE='/dev/null'
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else
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RO_RULES_FILE=$RULES_FILE
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RULES_FILE=$tmp_rules_file
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fi
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}
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# Return the name of the first free device.
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raw_find_next_available() {
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local links="$1"
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local basename=${links%%[ 0-9]*}
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local max=-1
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for name in $links; do
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local num=${name#$basename}
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[ "$num" ] || num=0
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[ $num -gt $max ] && max=$num
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done
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local max=$(($max + 1))
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# "name0" actually is just "name"
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[ $max -eq 0 ] && return
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echo "$max"
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}
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# Find all rules matching a key (with action) and a pattern.
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find_all_rules() {
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local key="$1"
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local linkre="$2"
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local match="$3"
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[ -e $RULES_FILE ] || return
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local search='.*[[:space:],]'"$key"'"\('"$linkre"'\)"[[:space:]]*\(,.*\|\\\|\)$'
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echo $(sed -n -e "${match}s/${search}/\1/p" $RO_RULES_FILE $RULES_FILE)
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}
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