/dracut-logger.sh
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Possible License(s): GPL-2.0
- #!/bin/bash
- #
- # logging faciality module for dracut both at build- and boot-time
- #
- # Copyright 2010 Amadeusz Żołnowski <aidecoe@aidecoe.name>
- #
- # 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/>.
- __DRACUT_LOGGER__=1
- ## @brief Logging facility module for dracut both at build- and boot-time.
- #
- # @section intro Introduction
- #
- # The logger takes a bit from Log4j philosophy. There are defined 6 logging
- # levels:
- # - TRACE (6)
- # The TRACE Level designates finer-grained informational events than the
- # DEBUG.
- # - DEBUG (5)
- # The DEBUG Level designates fine-grained informational events that are most
- # useful to debug an application.
- # - INFO (4)
- # The INFO level designates informational messages that highlight the
- # progress of the application at coarse-grained level.
- # - WARN (3)
- # The WARN level designates potentially harmful situations.
- # - ERROR (2)
- # The ERROR level designates error events that might still allow the
- # application to continue running.
- # - FATAL (1)
- # The FATAL level designates very severe error events that will presumably
- # lead the application to abort.
- # Descriptions are borrowed from Log4j documentation:
- # http://logging.apache.org/log4j/1.2/apidocs/org/apache/log4j/Level.html
- #
- # @section usage Usage
- #
- # First of all you have to start with dlog_init() function which initializes
- # required variables. Don't call any other logging function before that one!
- # If you're ready with this, you can use following functions which corresponds
- # clearly to levels listed in @ref intro Introduction. Here they are:
- # - dtrace()
- # - ddebug()
- # - dinfo()
- # - dwarn()
- # - derror()
- # - dfatal()
- # They take all arguments given as a single message to be logged. See dlog()
- # function for details how it works. Note that you shouldn't use dlog() by
- # yourself. It's wrapped with above functions.
- #
- # @see dlog_init() dlog()
- #
- # @section conf Configuration
- #
- # Logging is controlled by following global variables:
- # - @var stdloglvl - logging level to standard error (console output)
- # - @var sysloglvl - logging level to syslog (by logger command)
- # - @var fileloglvl - logging level to file
- # - @var kmsgloglvl - logging level to /dev/kmsg (only for boot-time)
- # - @var logfile - log file which is used when @var fileloglvl is higher
- # than 0
- # and two global variables: @var maxloglvl and @var syslogfacility which <b>must
- # not</b> be overwritten. Both are set by dlog_init(). @var maxloglvl holds
- # maximum logging level of those three and indicates that dlog_init() was run.
- # @var syslogfacility is set either to 'user' (when building initramfs) or
- # 'daemon' (when booting).
- #
- # Logging level set by the variable means that messages from this logging level
- # and above (FATAL is the highest) will be shown. Logging levels may be set
- # independently for each destination (stderr, syslog, file, kmsg).
- #
- # @see dlog_init()
- ## @brief Initializes dracut Logger.
- #
- # @retval 1 if something has gone wrong
- # @retval 0 on success.
- #
- # @note This function need to be called before any other from this file.
- #
- # If any of the variables is not set, this function set it to default:
- # - @var stdloglvl = 4 (info)
- # - @var sysloglvl = 0 (no logging)
- # - @var fileloglvl is set to 4 when @var logfile is set too, otherwise it's
- # - @var kmsgloglvl = 0 (no logging)
- # set to 0
- #
- # @warning Function sets global variables @var maxloglvl and @syslogfacility.
- # See file doc comment for details.
- dlog_init() {
- local __oldumask
- local ret=0; local errmsg
- [ -z "$stdloglvl" ] && stdloglvl=4
- [ -z "$sysloglvl" ] && sysloglvl=0
- [ -z "$kmsgloglvl" ] && kmsgloglvl=0
- # Skip initialization if it's already done.
- [ -n "$maxloglvl" ] && return 0
- if [ -z "$fileloglvl" ]; then
- [ -w "$logfile" ] && fileloglvl=4 || fileloglvl=0
- elif (( $fileloglvl > 0 )); then
- if [[ $logfile ]]; then
- __oldumask=$(umask)
- umask 0377
- ! [ -e "$logfile" ] && >"$logfile"
- umask $__oldumask
- if [ -w "$logfile" -a -f "$logfile" ]; then
- # Mark new run in the log file
- echo >>"$logfile"
- if command -v date >/dev/null; then
- echo "=== $(date) ===" >>"$logfile"
- else
- echo "===============================================" >>"$logfile"
- fi
- echo >>"$logfile"
- else
- # We cannot log to file, so turn this facility off.
- fileloglvl=0
- ret=1
- errmsg="'$logfile' is not a writable file"
- fi
- fi
- fi
- if (( $UID != 0 )); then
- kmsgloglvl=0
- sysloglvl=0
- fi
- if (( $sysloglvl > 0 )); then
- if [[ -d /run/systemd/journal ]] \
- && type -P systemd-cat &>/dev/null \
- && systemctl --quiet is-active systemd-journald.socket &>/dev/null \
- && { echo "dracut-$DRACUT_VERSION" | systemd-cat -t 'dracut' &>/dev/null; } ; then
- readonly _dlogdir="$(mktemp --tmpdir="$TMPDIR/" -d -t dracut-log.XXXXXX)"
- readonly _systemdcatfile="$_dlogdir/systemd-cat"
- mkfifo "$_systemdcatfile"
- readonly _dlogfd=15
- systemd-cat -t 'dracut' --level-prefix=true <"$_systemdcatfile" &
- exec 15>"$_systemdcatfile"
- elif ! [ -S /dev/log -a -w /dev/log ] || ! command -v logger >/dev/null; then
- # We cannot log to syslog, so turn this facility off.
- kmsgloglvl=$sysloglvl
- sysloglvl=0
- ret=1
- errmsg="No '/dev/log' or 'logger' included for syslog logging"
- fi
- fi
- if (($sysloglvl > 0)) || (($kmsgloglvl > 0 )); then
- if [ -n "$dracutbasedir" ]; then
- readonly syslogfacility=user
- else
- readonly syslogfacility=daemon
- fi
- export syslogfacility
- fi
- local lvl; local maxloglvl_l=0
- for lvl in $stdloglvl $sysloglvl $fileloglvl $kmsgloglvl; do
- (( $lvl > $maxloglvl_l )) && maxloglvl_l=$lvl
- done
- readonly maxloglvl=$maxloglvl_l
- export maxloglvl
- if (($stdloglvl < 6)) && (($kmsgloglvl < 6)) && (($fileloglvl < 6)) && (($sysloglvl < 6)); then
- unset dtrace
- dtrace() { :; };
- fi
- if (($stdloglvl < 5)) && (($kmsgloglvl < 5)) && (($fileloglvl < 5)) && (($sysloglvl < 5)); then
- unset ddebug
- ddebug() { :; };
- fi
- if (($stdloglvl < 4)) && (($kmsgloglvl < 4)) && (($fileloglvl < 4)) && (($sysloglvl < 4)); then
- unset dinfo
- dinfo() { :; };
- fi
- if (($stdloglvl < 3)) && (($kmsgloglvl < 3)) && (($fileloglvl < 3)) && (($sysloglvl < 3)); then
- unset dwarn
- dwarn() { :; };
- unset dwarning
- dwarning() { :; };
- fi
- if (($stdloglvl < 2)) && (($kmsgloglvl < 2)) && (($fileloglvl < 2)) && (($sysloglvl < 2)); then
- unset derror
- derror() { :; };
- fi
- if (($stdloglvl < 1)) && (($kmsgloglvl < 1)) && (($fileloglvl < 1)) && (($sysloglvl < 1)); then
- unset dfatal
- dfatal() { :; };
- fi
- [ -n "$errmsg" ] && derror "$errmsg"
- return $ret
- }
- ## @brief Converts numeric logging level to the first letter of level name.
- #
- # @param lvl Numeric logging level in range from 1 to 6.
- # @retval 1 if @a lvl is out of range.
- # @retval 0 if @a lvl is correct.
- # @result Echoes first letter of level name.
- _lvl2char() {
- case "$1" in
- 1) echo F;;
- 2) echo E;;
- 3) echo W;;
- 4) echo I;;
- 5) echo D;;
- 6) echo T;;
- *) return 1;;
- esac
- }
- ## @brief Converts numeric level to logger priority defined by POSIX.2.
- #
- # @param lvl Numeric logging level in range from 1 to 6.
- # @retval 1 if @a lvl is out of range.
- # @retval 0 if @a lvl is correct.
- # @result Echoes logger priority.
- _lvl2syspri() {
- printf $syslogfacility.
- case "$1" in
- 1) echo crit;;
- 2) echo error;;
- 3) echo warning;;
- 4) echo info;;
- 5) echo debug;;
- 6) echo debug;;
- *) return 1;;
- esac
- }
- ## @brief Converts dracut-logger numeric level to syslog log level
- #
- # @param lvl Numeric logging level in range from 1 to 6.
- # @retval 1 if @a lvl is out of range.
- # @retval 0 if @a lvl is correct.
- # @result Echoes kernel console numeric log level
- #
- # Conversion is done as follows:
- #
- # <tt>
- # FATAL(1) -> LOG_EMERG (0)
- # none -> LOG_ALERT (1)
- # none -> LOG_CRIT (2)
- # ERROR(2) -> LOG_ERR (3)
- # WARN(3) -> LOG_WARNING (4)
- # none -> LOG_NOTICE (5)
- # INFO(4) -> LOG_INFO (6)
- # DEBUG(5) -> LOG_DEBUG (7)
- # TRACE(6) /
- # </tt>
- #
- # @see /usr/include/sys/syslog.h
- _dlvl2syslvl() {
- local lvl
- case "$1" in
- 1) lvl=0;;
- 2) lvl=3;;
- 3) lvl=4;;
- 4) lvl=6;;
- 5) lvl=7;;
- 6) lvl=7;;
- *) return 1;;
- esac
- [ "$syslogfacility" = user ] && echo $((8+$lvl)) || echo $((24+$lvl))
- }
- ## @brief Prints to stderr and/or writes to file, to syslog and/or /dev/kmsg
- # given message with given level (priority).
- #
- # @param lvl Numeric logging level.
- # @param msg Message.
- # @retval 0 It's always returned, even if logging failed.
- #
- # @note This function is not supposed to be called manually. Please use
- # dtrace(), ddebug(), or others instead which wrap this one.
- #
- # This is core logging function which logs given message to standard error, file
- # and/or syslog (with POSIX shell command <tt>logger</tt>) and/or to /dev/kmsg.
- # The format is following:
- #
- # <tt>X: some message</tt>
- #
- # where @c X is the first letter of logging level. See module description for
- # details on that.
- #
- # Message to syslog is sent with tag @c dracut. Priorities are mapped as
- # following:
- # - @c FATAL to @c crit
- # - @c ERROR to @c error
- # - @c WARN to @c warning
- # - @c INFO to @c info
- # - @c DEBUG and @c TRACE both to @c debug
- _do_dlog() {
- local lvl="$1"; shift
- local lvlc=$(_lvl2char "$lvl") || return 0
- local msg="$*"
- local lmsg="$lvlc: $*"
- (( $lvl <= $stdloglvl )) && echo "$msg" >&2
- if (( $lvl <= $sysloglvl )); then
- if [[ "$_dlogfd" ]]; then
- printf -- "<%s>%s\n" "$(($(_dlvl2syslvl $lvl) & 7))" "$msg" >&$_dlogfd
- else
- logger -t "dracut[$$]" -p $(_lvl2syspri $lvl) -- "$msg"
- fi
- fi
- if (( $lvl <= $fileloglvl )) && [[ -w "$logfile" ]] && [[ -f "$logfile" ]]; then
- echo "$lmsg" >>"$logfile"
- fi
- (( $lvl <= $kmsgloglvl )) && \
- echo "<$(_dlvl2syslvl $lvl)>dracut[$$] $msg" >/dev/kmsg
- }
- ## @brief Internal helper function for _do_dlog()
- #
- # @param lvl Numeric logging level.
- # @param msg Message.
- # @retval 0 It's always returned, even if logging failed.
- #
- # @note This function is not supposed to be called manually. Please use
- # dtrace(), ddebug(), or others instead which wrap this one.
- #
- # This function calls _do_dlog() either with parameter msg, or if
- # none is given, it will read standard input and will use every line as
- # a message.
- #
- # This enables:
- # dwarn "This is a warning"
- # echo "This is a warning" | dwarn
- dlog() {
- [ -z "$maxloglvl" ] && return 0
- (( $1 <= $maxloglvl )) || return 0
- if (( $# > 1 )); then
- _do_dlog "$@"
- else
- while read line; do
- _do_dlog "$1" "$line"
- done
- fi
- }
- ## @brief Logs message at TRACE level (6)
- #
- # @param msg Message.
- # @retval 0 It's always returned, even if logging failed.
- dtrace() {
- set +x
- dlog 6 "$@"
- [ -n "$debug" ] && set -x || :
- }
- ## @brief Logs message at DEBUG level (5)
- #
- # @param msg Message.
- # @retval 0 It's always returned, even if logging failed.
- ddebug() {
- set +x
- dlog 5 "$@"
- [ -n "$debug" ] && set -x || :
- }
- ## @brief Logs message at INFO level (4)
- #
- # @param msg Message.
- # @retval 0 It's always returned, even if logging failed.
- dinfo() {
- set +x
- dlog 4 "$@"
- [ -n "$debug" ] && set -x || :
- }
- ## @brief Logs message at WARN level (3)
- #
- # @param msg Message.
- # @retval 0 It's always returned, even if logging failed.
- dwarn() {
- set +x
- dlog 3 "$@"
- [ -n "$debug" ] && set -x || :
- }
- ## @brief It's an alias to dwarn() function.
- #
- # @param msg Message.
- # @retval 0 It's always returned, even if logging failed.
- dwarning() {
- set +x
- dwarn "$@"
- [ -n "$debug" ] && set -x || :
- }
- ## @brief Logs message at ERROR level (2)
- #
- # @param msg Message.
- # @retval 0 It's always returned, even if logging failed.
- derror() {
- set +x
- dlog 2 "$@"
- [ -n "$debug" ] && set -x || :
- }
- ## @brief Logs message at FATAL level (1)
- #
- # @param msg Message.
- # @retval 0 It's always returned, even if logging failed.
- dfatal() {
- set +x
- dlog 1 "$@"
- [ -n "$debug" ] && set -x || :
- }