dracut-logger.sh

   1 #!/bin/bash
   2 # -*- mode: shell-script; indent-tabs-mode: nil; sh-basic-offset: 4; -*-
   3 # ex: ts=8 sw=4 et filetype=sh
   4 #
   5 # logging faciality module for dracut both at build- and boot-time
   6 #
   7 # Copyright 2010 Amadeusz Żołnowski <aidecoe@aidecoe.name>
   8 #
   9 # This program is free software; you can redistribute it and/or modify
  10 # it under the terms of the GNU General Public License as published by
  11 # the Free Software Foundation; either version 2 of the License, or
  12 # (at your option) any later version.
  13 #
  14 # This program is distributed in the hope that it will be useful,
  15 # but WITHOUT ANY WARRANTY; without even the implied warranty of
  16 # MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  17 # GNU General Public License for more details.
  18 #
  19 # You should have received a copy of the GNU General Public License
  20 # along with this program.  If not, see <http://www.gnu.org/licenses/>.
  21
  22
  23 __DRACUT_LOGGER__=1
  24
  25
  26 ## @brief Logging facility module for dracut both at build- and boot-time.
  27 #
  28 # @section intro Introduction
  29 #
  30 # The logger takes a bit from Log4j philosophy. There are defined 6 logging
  31 # levels:
  32 #   - TRACE (6)
  33 #     The TRACE Level designates finer-grained informational events than the
  34 #     DEBUG.
  35 #   - DEBUG (5)
  36 #     The DEBUG Level designates fine-grained informational events that are most
  37 #     useful to debug an application.
  38 #   - INFO (4)
  39 #     The INFO level designates informational messages that highlight the
  40 #     progress of the application at coarse-grained level.
  41 #   - WARN (3)
  42 #     The WARN level designates potentially harmful situations.
  43 #   - ERROR (2)
  44 #     The ERROR level designates error events that might still allow the
  45 #     application to continue running.
  46 #   - FATAL (1)
  47 #     The FATAL level designates very severe error events that will presumably
  48 #     lead the application to abort.
  49 # Descriptions are borrowed from Log4j documentation:
  50 # http://logging.apache.org/log4j/1.2/apidocs/org/apache/log4j/Level.html
  51 #
  52 # @section usage Usage
  53 #
  54 # First of all you have to start with dlog_init() function which initializes
  55 # required variables. Don't call any other logging function before that one!
  56 # If you're ready with this, you can use following functions which corresponds
  57 # clearly to levels listed in @ref intro Introduction. Here they are:
  58 #   - dtrace()
  59 #   - ddebug()
  60 #   - dinfo()
  61 #   - dwarn()
  62 #   - derror()
  63 #   - dfatal()
  64 # They take all arguments given as a single message to be logged. See dlog()
  65 # function for details how it works. Note that you shouldn't use dlog() by
  66 # yourself. It's wrapped with above functions.
  67 #
  68 # @see dlog_init() dlog()
  69 #
  70 # @section conf Configuration
  71 #
  72 # Logging is controlled by following global variables:
  73 #   - @var stdloglvl - logging level to standard error (console output)
  74 #   - @var sysloglvl - logging level to syslog (by logger command)
  75 #   - @var fileloglvl - logging level to file
  76 #   - @var kmsgloglvl - logging level to /dev/kmsg (only for boot-time)
  77 #   - @var logfile - log file which is used when @var fileloglvl is higher
  78 #   than 0
  79 # and two global variables: @var maxloglvl and @var syslogfacility which <b>must
  80 # not</b> be overwritten. Both are set by dlog_init(). @var maxloglvl holds
  81 # maximum logging level of those three and indicates that dlog_init() was run.
  82 # @var syslogfacility is set either to 'user' (when building initramfs) or
  83 # 'daemon' (when booting).
  84 #
  85 # Logging level set by the variable means that messages from this logging level
  86 # and above (FATAL is the highest) will be shown. Logging levels may be set
  87 # independently for each destination (stderr, syslog, file, kmsg).
  88 #
  89 # @see dlog_init()
  90
  91
  92 ## @brief Initializes dracut Logger.
  93 #
  94 # @retval 1 if something has gone wrong
  95 # @retval 0 on success.
  96 #
  97 # @note This function need to be called before any other from this file.
  98 #
  99 # If any of the variables is not set, this function set it to default:
 100 #   - @var stdloglvl = 4 (info)
 101 #   - @var sysloglvl = 0 (no logging)
 102 #   - @var fileloglvl is set to 4 when @var logfile is set too, otherwise it's
 103 #   - @var kmsgloglvl = 0 (no logging)
 104 #   set to 0
 105 #
 106 # @warning Function sets global variables @var maxloglvl and @syslogfacility.
 107 # See file doc comment for details.
 108 dlog_init() {
 109     local __oldumask
 110     local ret=0; local errmsg
 111     [ -z "$stdloglvl" ] && stdloglvl=4
 112     [ -z "$sysloglvl" ] && sysloglvl=0
 113     [ -z "$kmsgloglvl" ] && kmsgloglvl=0
 114     # Skip initialization if it's already done.
 115     [ -n "$maxloglvl" ] && return 0
 116
 117     if [ -z "$fileloglvl" ]; then
 118         [ -w "$logfile" ] && fileloglvl=4 || fileloglvl=0
 119     elif (( $fileloglvl > 0 )); then
 120         if [[ $logfile ]]; then
 121             __oldumask=$(umask)
 122             umask 0377
 123             ! [ -e "$logfile" ] && >"$logfile"
 124             umask $__oldumask
 125             if [ -w "$logfile" -a -f "$logfile" ]; then
 126             # Mark new run in the log file
 127                 echo >>"$logfile"
 128                 if command -v date >/dev/null; then
 129                     echo "=== $(date) ===" >>"$logfile"
 130                 else
 131                     echo "===============================================" >>"$logfile"
 132                 fi
 133                 echo >>"$logfile"
 134             else
 135             # We cannot log to file, so turn this facility off.
 136                 fileloglvl=0
 137                 ret=1
 138                 errmsg="'$logfile' is not a writable file"
 139             fi
 140         fi
 141     fi
 142
 143     if (( $UID  != 0 )); then
 144         kmsgloglvl=0
 145         sysloglvl=0
 146     fi
 147
 148     if (( $sysloglvl > 0 )); then
 149         if [[ -d /run/systemd/journal ]] \
 150             && type -P systemd-cat &>/dev/null \
 151             && systemctl --quiet is-active systemd-journald.socket &>/dev/null \
 152             && { echo "dracut-$DRACUT_VERSION" | systemd-cat -t 'dracut' &>/dev/null; } ; then
 153             readonly _dlogdir="$(mktemp --tmpdir="$TMPDIR/" -d -t dracut-log.XXXXXX)"
 154             readonly _systemdcatfile="$_dlogdir/systemd-cat"
 155             mkfifo "$_systemdcatfile"
 156             readonly _dlogfd=15
 157             systemd-cat -t 'dracut' --level-prefix=true <"$_systemdcatfile" &
 158             exec 15>"$_systemdcatfile"
 159         elif ! [ -S /dev/log -a -w /dev/log ] || ! command -v logger >/dev/null; then
 160             # We cannot log to syslog, so turn this facility off.
 161             kmsgloglvl=$sysloglvl
 162             sysloglvl=0
 163             ret=1
 164             errmsg="No '/dev/log' or 'logger' included for syslog logging"
 165         fi
 166     fi
 167
 168     if (($sysloglvl > 0)) || (($kmsgloglvl > 0 )); then
 169         if [ -n "$dracutbasedir" ]; then
 170             readonly syslogfacility=user
 171         else
 172             readonly syslogfacility=daemon
 173         fi
 174         export syslogfacility
 175     fi
 176
 177     local lvl; local maxloglvl_l=0
 178     for lvl in $stdloglvl $sysloglvl $fileloglvl $kmsgloglvl; do
 179         (( $lvl > $maxloglvl_l )) && maxloglvl_l=$lvl
 180     done
 181     readonly maxloglvl=$maxloglvl_l
 182     export maxloglvl
 183
 184
 185     if (($stdloglvl < 6)) && (($kmsgloglvl < 6)) && (($fileloglvl < 6)) && (($sysloglvl < 6)); then
 186         unset dtrace
 187         dtrace() { :; };
 188     fi
 189
 190     if (($stdloglvl < 5)) && (($kmsgloglvl < 5)) && (($fileloglvl < 5)) && (($sysloglvl < 5)); then
 191         unset ddebug
 192         ddebug() { :; };
 193     fi
 194
 195     if (($stdloglvl < 4)) && (($kmsgloglvl < 4)) && (($fileloglvl < 4)) && (($sysloglvl < 4)); then
 196         unset dinfo
 197         dinfo() { :; };
 198     fi
 199
 200     if (($stdloglvl < 3)) && (($kmsgloglvl < 3)) && (($fileloglvl < 3)) && (($sysloglvl < 3)); then
 201         unset dwarn
 202         dwarn() { :; };
 203         unset dwarning
 204         dwarning() { :; };
 205     fi
 206
 207     if (($stdloglvl < 2)) && (($kmsgloglvl < 2)) && (($fileloglvl < 2)) && (($sysloglvl < 2)); then
 208         unset derror
 209         derror() { :; };
 210     fi
 211
 212     if (($stdloglvl < 1)) && (($kmsgloglvl < 1)) && (($fileloglvl < 1)) && (($sysloglvl < 1)); then
 213         unset dfatal
 214         dfatal() { :; };
 215     fi
 216
 217     [ -n "$errmsg" ] && derror "$errmsg"
 218
 219     return $ret
 220 }
 221
 222 ## @brief Converts numeric logging level to the first letter of level name.
 223 #
 224 # @param lvl Numeric logging level in range from 1 to 6.
 225 # @retval 1 if @a lvl is out of range.
 226 # @retval 0 if @a lvl is correct.
 227 # @result Echoes first letter of level name.
 228 _lvl2char() {
 229     case "$1" in
 230         1) echo F;;
 231         2) echo E;;
 232         3) echo W;;
 233         4) echo I;;
 234         5) echo D;;
 235         6) echo T;;
 236         *) return 1;;
 237     esac
 238 }
 239
 240 ## @brief Converts numeric level to logger priority defined by POSIX.2.
 241 #
 242 # @param lvl Numeric logging level in range from 1 to 6.
 243 # @retval 1 if @a lvl is out of range.
 244 # @retval 0 if @a lvl is correct.
 245 # @result Echoes logger priority.
 246 _lvl2syspri() {
 247     printf $syslogfacility.
 248     case "$1" in
 249         1) echo crit;;
 250         2) echo error;;
 251         3) echo warning;;
 252         4) echo info;;
 253         5) echo debug;;
 254         6) echo debug;;
 255         *) return 1;;
 256     esac
 257 }
 258
 259 ## @brief Converts dracut-logger numeric level to syslog log level
 260 #
 261 # @param lvl Numeric logging level in range from 1 to 6.
 262 # @retval 1 if @a lvl is out of range.
 263 # @retval 0 if @a lvl is correct.
 264 # @result Echoes kernel console numeric log level
 265 #
 266 # Conversion is done as follows:
 267 #
 268 # <tt>
 269 #   FATAL(1) -> LOG_EMERG (0)
 270 #   none     -> LOG_ALERT (1)
 271 #   none     -> LOG_CRIT (2)
 272 #   ERROR(2) -> LOG_ERR (3)
 273 #   WARN(3)  -> LOG_WARNING (4)
 274 #   none     -> LOG_NOTICE (5)
 275 #   INFO(4)  -> LOG_INFO (6)
 276 #   DEBUG(5) -> LOG_DEBUG (7)
 277 #   TRACE(6) /
 278 # </tt>
 279 #
 280 # @see /usr/include/sys/syslog.h
 281 _dlvl2syslvl() {
 282     local lvl
 283
 284     case "$1" in
 285         1) lvl=0;;
 286         2) lvl=3;;
 287         3) lvl=4;;
 288         4) lvl=6;;
 289         5) lvl=7;;
 290         6) lvl=7;;
 291         *) return 1;;
 292     esac
 293
 294     [ "$syslogfacility" = user ] && echo $((8+$lvl)) || echo $((24+$lvl))
 295 }
 296
 297 ## @brief Prints to stderr and/or writes to file, to syslog and/or /dev/kmsg
 298 # given message with given level (priority).
 299 #
 300 # @param lvl Numeric logging level.
 301 # @param msg Message.
 302 # @retval 0 It's always returned, even if logging failed.
 303 #
 304 # @note This function is not supposed to be called manually. Please use
 305 # dtrace(), ddebug(), or others instead which wrap this one.
 306 #
 307 # This is core logging function which logs given message to standard error, file
 308 # and/or syslog (with POSIX shell command <tt>logger</tt>) and/or to /dev/kmsg.
 309 # The format is following:
 310 #
 311 # <tt>X: some message</tt>
 312 #
 313 # where @c X is the first letter of logging level. See module description for
 314 # details on that.
 315 #
 316 # Message to syslog is sent with tag @c dracut. Priorities are mapped as
 317 # following:
 318 #   - @c FATAL to @c crit
 319 #   - @c ERROR to @c error
 320 #   - @c WARN to @c warning
 321 #   - @c INFO to @c info
 322 #   - @c DEBUG and @c TRACE both to @c debug
 323 _do_dlog() {
 324     local lvl="$1"; shift
 325     local lvlc=$(_lvl2char "$lvl") || return 0
 326     local msg="$*"
 327     local lmsg="$lvlc: $*"
 328
 329     (( $lvl <= $stdloglvl )) && echo "$msg" >&2
 330
 331     if (( $lvl <= $sysloglvl )); then
 332         if [[ "$_dlogfd" ]]; then
 333             printf -- "<%s>%s\n" "$(($(_dlvl2syslvl $lvl) & 7))" "$msg" >&$_dlogfd
 334         else
 335             logger -t "dracut[$$]" -p $(_lvl2syspri $lvl) -- "$msg"
 336         fi
 337     fi
 338
 339     if (( $lvl <= $fileloglvl )) && [[ -w "$logfile" ]] && [[ -f "$logfile" ]]; then
 340         echo "$lmsg" >>"$logfile"
 341     fi
 342
 343     (( $lvl <= $kmsgloglvl )) && \
 344         echo "<$(_dlvl2syslvl $lvl)>dracut[$$] $msg" >/dev/kmsg
 345 }
 346
 347 ## @brief Internal helper function for _do_dlog()
 348 #
 349 # @param lvl Numeric logging level.
 350 # @param msg Message.
 351 # @retval 0 It's always returned, even if logging failed.
 352 #
 353 # @note This function is not supposed to be called manually. Please use
 354 # dtrace(), ddebug(), or others instead which wrap this one.
 355 #
 356 # This function calls _do_dlog() either with parameter msg, or if
 357 # none is given, it will read standard input and will use every line as
 358 # a message.
 359 #
 360 # This enables:
 361 # dwarn "This is a warning"
 362 # echo "This is a warning" | dwarn
 363 dlog() {
 364     [ -z "$maxloglvl" ] && return 0
 365     (( $1 <= $maxloglvl )) || return 0
 366
 367     if (( $# > 1 )); then
 368         _do_dlog "$@"
 369     else
 370         while read line; do
 371             _do_dlog "$1" "$line"
 372         done
 373     fi
 374 }
 375
 376 ## @brief Logs message at TRACE level (6)
 377 #
 378 # @param msg Message.
 379 # @retval 0 It's always returned, even if logging failed.
 380 dtrace() {
 381     set +x
 382     dlog 6 "$@"
 383     [ -n "$debug" ] && set -x || :
 384 }
 385
 386 ## @brief Logs message at DEBUG level (5)
 387 #
 388 # @param msg Message.
 389 # @retval 0 It's always returned, even if logging failed.
 390 ddebug() {
 391     set +x
 392     dlog 5 "$@"
 393     [ -n "$debug" ] && set -x || :
 394 }
 395
 396 ## @brief Logs message at INFO level (4)
 397 #
 398 # @param msg Message.
 399 # @retval 0 It's always returned, even if logging failed.
 400 dinfo() {
 401     set +x
 402     dlog 4 "$@"
 403     [ -n "$debug" ] && set -x || :
 404 }
 405
 406 ## @brief Logs message at WARN level (3)
 407 #
 408 # @param msg Message.
 409 # @retval 0 It's always returned, even if logging failed.
 410 dwarn() {
 411     set +x
 412     dlog 3 "$@"
 413     [ -n "$debug" ] && set -x || :
 414 }
 415
 416 ## @brief It's an alias to dwarn() function.
 417 #
 418 # @param msg Message.
 419 # @retval 0 It's always returned, even if logging failed.
 420 dwarning() {
 421     set +x
 422     dwarn "$@"
 423     [ -n "$debug" ] && set -x || :
 424 }
 425
 426 ## @brief Logs message at ERROR level (2)
 427 #
 428 # @param msg Message.
 429 # @retval 0 It's always returned, even if logging failed.
 430 derror() {
 431     set +x
 432     dlog 2 "$@"
 433     [ -n "$debug" ] && set -x || :
 434 }
 435
 436 ## @brief Logs message at FATAL level (1)
 437 #
 438 # @param msg Message.
 439 # @retval 0 It's always returned, even if logging failed.
 440 dfatal() {
 441     set +x
 442     dlog 1 "$@"
 443     [ -n "$debug" ] && set -x || :
 444 }