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kdump-logger.sh
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#!/bin/bash # # This comes from the dracut-logger.sh # # The logger defined 4 logging levels: # - ddebug (4) # The DEBUG Level designates fine-grained informational events that are most # useful to debug an application. # - dinfo (3) # The INFO level designates informational messages that highlight the # progress of the application at coarse-grained level. # - dwarn (2) # The WARN level designates potentially harmful situations. # - derror (1) # The ERROR level designates error events that might still allow the # application to continue running. # # Logging is controlled by following global variables: # - @var kdump_stdloglvl - logging level to standard error (console output) # - @var kdump_sysloglvl - logging level to syslog (by logger command) # - @var kdump_kmsgloglvl - logging level to /dev/kmsg (only for boot-time) # # If any of the variables is not set, the function dlog_init() sets it to default: # - In the first kernel: # - @var kdump_stdloglvl = 3 (info) # - @var kdump_sysloglvl = 0 (no logging) # - @var kdump_kmsgloglvl = 0 (no logging) # # -In the second kernel: # - @var kdump_stdloglvl = 0 (no logging) # - @var kdump_sysloglvl = 3 (info) # - @var kdump_kmsgloglvl = 0 (no logging) # # 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! # # Define vairables for the log levels in this module. kdump_stdloglvl="" kdump_sysloglvl="" kdump_kmsgloglvl="" # The dracut-lib.sh is only available in the second kernel, and it won't # be used in the first kernel because the dracut-lib.sh is invisible in # the first kernel. if [ -f /lib/dracut-lib.sh ]; then . /lib/dracut-lib.sh fi # @brief Get the log level from kernel command line. # @retval 1 if something has gone wrong # @retval 0 on success. # get_kdump_loglvl() { (type -p getarg) && kdump_sysloglvl=$(getarg rd.kdumploglvl) [ -z "$kdump_sysloglvl" ] && return 1; (type -p isdigit) && isdigit $kdump_sysloglvl [ $? -ne 0 ] && return 1; return 0 } # @brief Check the log level. # @retval 1 if something has gone wrong # @retval 0 on success. # check_loglvl() { case "$1" in 0|1|2|3|4) return 0 ;; *) return 1 ;; esac } # @brief Initializes Logger. # @retval 1 if something has gone wrong # @retval 0 on success. # dlog_init() { local ret=0; local errmsg if [ -s /proc/vmcore ];then get_kdump_loglvl if [ $? -ne 0 ];then logger -t "kdump[$$]" -p warn -- "Kdump is using the default log level(3)." kdump_sysloglvl=3 fi kdump_stdloglvl=0 kdump_kmsgloglvl=0 else kdump_stdloglvl=$KDUMP_STDLOGLVL kdump_sysloglvl=$KDUMP_SYSLOGLVL kdump_kmsgloglvl=$KDUMP_KMSGLOGLVL fi [ -z "$kdump_stdloglvl" ] && kdump_stdloglvl=3 [ -z "$kdump_sysloglvl" ] && kdump_sysloglvl=0 [ -z "$kdump_kmsgloglvl" ] && kdump_kmsgloglvl=0 for loglvl in "$kdump_stdloglvl" "$kdump_kmsgloglvl" "$kdump_sysloglvl"; do check_loglvl "$loglvl" if [ $? -ne 0 ]; then echo "Illegal log level: $kdump_stdloglvl $kdump_kmsgloglvl $kdump_sysloglvl" return 1 fi done # Skip initialization if it's already done. [ -n "$kdump_maxloglvl" ] && return 0 if [[ $UID -ne 0 ]]; then kdump_kmsgloglvl=0 kdump_sysloglvl=0 fi if [[ $kdump_sysloglvl -gt 0 ]]; then if [[ -d /run/systemd/journal ]] \ && type -P systemd-cat &>/dev/null \ && systemctl --quiet is-active systemd-journald.socket &>/dev/null; then readonly _systemdcatfile="/var/tmp/systemd-cat" mkfifo "$_systemdcatfile" &>/dev/null readonly _dlogfd=15 systemd-cat -t 'kdump' --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. kdump_kmsgloglvl=$kdump_sysloglvl kdump_sysloglvl=0 ret=1 errmsg="No '/dev/log' or 'logger' included for syslog logging" fi fi local lvl; local maxloglvl_l=0 for lvl in $kdump_stdloglvl $kdump_sysloglvl $kdump_kmsgloglvl; do [[ $lvl -gt $maxloglvl_l ]] && maxloglvl_l=$lvl done readonly kdump_maxloglvl=$maxloglvl_l export kdump_maxloglvl if [[ $kdump_stdloglvl -lt 4 ]] && [[ $kdump_kmsgloglvl -lt 4 ]] && [[ $kdump_sysloglvl -lt 4 ]]; then unset ddebug ddebug() { :; }; fi if [[ $kdump_stdloglvl -lt 3 ]] && [[ $kdump_kmsgloglvl -lt 3 ]] && [[ $kdump_sysloglvl -lt 3 ]]; then unset dinfo dinfo() { :; }; fi if [[ $kdump_stdloglvl -lt 2 ]] && [[ $kdump_kmsgloglvl -lt 2 ]] && [[ $kdump_sysloglvl -lt 2 ]]; then unset dwarn dwarn() { :; }; unset dwarning dwarning() { :; }; fi if [[ $kdump_stdloglvl -lt 1 ]] && [[ $kdump_kmsgloglvl -lt 1 ]] && [[ $kdump_sysloglvl -lt 1 ]]; then unset derror derror() { :; }; fi [ -n "$errmsg" ] && derror "$errmsg" return $ret } ## @brief Converts numeric level to logger priority defined by POSIX.2. # # @param lvl Numeric logging level in range from 1 to 4. # @retval 1 if @a lvl is out of range. # @retval 0 if @a lvl is correct. # @result Echoes logger priority. _lvl2syspri() { case "$1" in 1) echo error;; 2) echo warning;; 3) echo info;; 4) echo debug;; *) return 1;; esac } ## @brief Converts logger numeric level to syslog log level # # @param lvl Numeric logging level in range from 1 to 4. # @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) # none -> LOG_CRIT (2) # ERROR(1) -> LOG_ERR (3) # WARN(2) -> LOG_WARNING (4) # none -> LOG_NOTICE (5) # INFO(3) -> LOG_INFO (6) # DEBUG(4) -> LOG_DEBUG (7) # </tt> # # @see /usr/include/sys/syslog.h _dlvl2syslvl() { local lvl case "$1" in 1) lvl=3;; 2) lvl=4;; 3) lvl=6;; 4) lvl=7;; *) return 1;; esac # The number is constructed by multiplying the facility by 8 and then # adding the level. # About The Syslog Protocol, please refer to the RFC5424 for more details. echo $((24+$lvl)) } ## @brief Prints to stderr, 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 # dinfo(), ddebug(), or others instead which wrap this one. # # This is core logging function which logs given message to standard error # 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 kdump. Priorities are mapped as # following: # - @c ERROR to @c error # - @c WARN to @c warning # - @c INFO to @c info # - @c DEBUG to @c debug _do_dlog() { local lvl="$1"; shift local msg="$*" [[ $lvl -le $kdump_stdloglvl ]] && printf -- 'kdump: %s\n' "$msg" >&2 if [[ $lvl -le $kdump_sysloglvl ]]; then if [[ "$_dlogfd" ]]; then printf -- "<%s>%s\n" "$(($(_dlvl2syslvl $lvl) & 7))" "$msg" >&$_dlogfd else logger -t "kdump[$$]" -p $(_lvl2syspri $lvl) -- "$msg" fi fi [[ $lvl -le $kdump_kmsgloglvl ]] && \ echo "<$(_dlvl2syslvl $lvl)>kdump[$$] $msg" >/dev/kmsg } ## @brief Internal helper function for _do_dlog() # # @param lvl Numeric logging level. # @param msg Message. # @retval 0 It's always returned, even if logging failed. # # @note This function is not supposed to be called manually. Please use # dinfo(), ddebug(), or others instead which wrap this one. # # This function calls _do_dlog() either with parameter msg, or if # none is given, it will read standard input and will use every line as # a message. # # This enables: # dwarn "This is a warning" # echo "This is a warning" | dwarn dlog() { [ -z "$kdump_maxloglvl" ] && return 0 [[ $1 -le $kdump_maxloglvl ]] || return 0 if [[ $# -gt 1 ]]; then _do_dlog "$@" else while read line || [ -n "$line" ]; do _do_dlog "$1" "$line" done fi } ## @brief Logs message at DEBUG level (4) # # @param msg Message. # @retval 0 It's always returned, even if logging failed. ddebug() { set +x dlog 4 "$@" [ -n "$debug" ] && set -x || : } ## @brief Logs message at INFO level (3) # # @param msg Message. # @retval 0 It's always returned, even if logging failed. dinfo() { set +x dlog 3 "$@" [ -n "$debug" ] && set -x || : } ## @brief Logs message at WARN level (2) # # @param msg Message. # @retval 0 It's always returned, even if logging failed. dwarn() { set +x dlog 2 "$@" [ -n "$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 (1) # # @param msg Message. # @retval 0 It's always returned, even if logging failed. derror() { set +x dlog 1 "$@" [ -n "$debug" ] && set -x || : }