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dracut-logger.sh
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#!/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 _systemdcatfile="$DRACUT_TMPDIR/systemd-cat" mkfifo "$_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> # none -> LOG_EMERG (0) # none -> LOG_ALERT (1) # FATAL(1) -> 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 "$1" in 1) lvl=2;; 2) lvl=3;; 3) lvl=4;; 4) lvl=6;; 5) lvl=7;; 6) lvl=7;; *) return 1;; esac [ "$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 <= $stdloglvl )) && printf -- 'dracut: %s\n' "$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 || [ -n "$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 || : }
