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         if type -P systemd-cat &>/dev/null && (( $UID  == 0 )) ; then
 142             readonly _dlogdir="$(mktemp --tmpdir="$TMPDIR/" -d -t dracut-log.XXXXXX)"
 143             readonly _systemdcatfile="$_dlogdir/systemd-cat"
 144             mkfifo "$_systemdcatfile"
 145             readonly _dlogfd=15
 146             systemd-cat -t 'dracut' <"$_systemdcatfile" &
 147             exec 15>"$_systemdcatfile"
 148         fi
 149     fi
 150
 151     if (( $sysloglvl > 0 )); then
 152         if ! [ -S /dev/log -a -w /dev/log ] || ! command -v logger >/dev/null
 153         then
 154             # We cannot log to syslog, so turn this facility off.
 155             sysloglvl=0
 156             ret=1
 157             errmsg="No '/dev/log' or 'logger' included for syslog logging"
 158         fi
 159     fi
 160
 161     if (($sysloglvl > 0)) || (($kmsgloglvl > 0 )); then
 162         if [ -n "$dracutbasedir" ]; then
 163             readonly syslogfacility=user
 164         else
 165             readonly syslogfacility=daemon
 166         fi
 167         export syslogfacility
 168     fi
 169
 170     local lvl; local maxloglvl_l=0
 171     for lvl in $stdloglvl $sysloglvl $fileloglvl $kmsgloglvl; do
 172         (( $lvl > $maxloglvl_l )) && maxloglvl_l=$lvl
 173     done
 174     readonly maxloglvl=$maxloglvl_l
 175     export maxloglvl
 176
 177
 178     if (($stdloglvl < 6)) && (($kmsgloglvl < 6)) && (($fileloglvl < 6)); then
 179         unset dtrace
 180         dtrace() { :; };
 181     fi
 182
 183     if (($stdloglvl < 5)) && (($kmsgloglvl < 5)) && (($fileloglvl < 5)); then
 184         unset ddebug
 185         ddebug() { :; };
 186     fi
 187
 188     if (($stdloglvl < 4)) && (($kmsgloglvl < 4)) && (($fileloglvl < 4)); then
 189         unset dinfo
 190         dinfo() { :; };
 191     fi
 192
 193     if (($stdloglvl < 3)) && (($kmsgloglvl < 3)) && (($fileloglvl < 3)); then
 194         unset dwarn
 195         dwarn() { :; };
 196         unset dwarning
 197         dwarning() { :; };
 198     fi
 199
 200     if (($stdloglvl < 2)) && (($kmsgloglvl < 2)) && (($fileloglvl < 2)); then
 201         unset derror
 202         derror() { :; };
 203     fi
 204
 205     if (($stdloglvl < 1)) && (($kmsgloglvl < 1)) && (($fileloglvl < 1)); then
 206         unset dfatal
 207         dfatal() { :; };
 208     fi
 209
 210     [ -n "$errmsg" ] && derror "$errmsg"
 211
 212     return $ret
 213 }
 214
 215 ## @brief Converts numeric logging level to the first letter of level name.
 216 #
 217 # @param lvl Numeric logging level in range from 1 to 6.
 218 # @retval 1 if @a lvl is out of range.
 219 # @retval 0 if @a lvl is correct.
 220 # @result Echoes first letter of level name.
 221 _lvl2char() {
 222     case "$1" in
 223         1) echo F;;
 224         2) echo E;;
 225         3) echo W;;
 226         4) echo I;;
 227         5) echo D;;
 228         6) echo T;;
 229         *) return 1;;
 230     esac
 231 }
 232
 233 ## @brief Converts numeric level to logger priority defined by POSIX.2.
 234 #
 235 # @param lvl Numeric logging level in range from 1 to 6.
 236 # @retval 1 if @a lvl is out of range.
 237 # @retval 0 if @a lvl is correct.
 238 # @result Echoes logger priority.
 239 _lvl2syspri() {
 240     printf $syslogfacility.
 241     case "$1" in
 242         1) echo crit;;
 243         2) echo error;;
 244         3) echo warning;;
 245         4) echo info;;
 246         5) echo debug;;
 247         6) echo debug;;
 248         *) return 1;;
 249     esac
 250 }
 251
 252 ## @brief Converts dracut-logger numeric level to syslog log level
 253 #
 254 # @param lvl Numeric logging level in range from 1 to 6.
 255 # @retval 1 if @a lvl is out of range.
 256 # @retval 0 if @a lvl is correct.
 257 # @result Echoes kernel console numeric log level
 258 #
 259 # Conversion is done as follows:
 260 #
 261 # <tt>
 262 #   FATAL(1) -> LOG_EMERG (0)
 263 #   none     -> LOG_ALERT (1)
 264 #   none     -> LOG_CRIT (2)
 265 #   ERROR(2) -> LOG_ERR (3)
 266 #   WARN(3)  -> LOG_WARNING (4)
 267 #   none     -> LOG_NOTICE (5)
 268 #   INFO(4)  -> LOG_INFO (6)
 269 #   DEBUG(5) -> LOG_DEBUG (7)
 270 #   TRACE(6) /
 271 # </tt>
 272 #
 273 # @see /usr/include/sys/syslog.h
 274 _dlvl2syslvl() {
 275     local lvl
 276
 277     case "$1" in
 278         1) lvl=0;;
 279         2) lvl=3;;
 280         3) lvl=4;;
 281         4) lvl=6;;
 282         5) lvl=7;;
 283         6) lvl=7;;
 284         *) return 1;;
 285     esac
 286
 287     [ "$syslogfacility" = user ] && echo $((8+$lvl)) || echo $((24+$lvl))
 288 }
 289
 290 ## @brief Prints to stderr and/or writes to file, to syslog and/or /dev/kmsg
 291 # given message with given level (priority).
 292 #
 293 # @param lvl Numeric logging level.
 294 # @param msg Message.
 295 # @retval 0 It's always returned, even if logging failed.
 296 #
 297 # @note This function is not supposed to be called manually. Please use
 298 # dtrace(), ddebug(), or others instead which wrap this one.
 299 #
 300 # This is core logging function which logs given message to standard error, file
 301 # and/or syslog (with POSIX shell command <tt>logger</tt>) and/or to /dev/kmsg.
 302 # The format is following:
 303 #
 304 # <tt>X: some message</tt>
 305 #
 306 # where @c X is the first letter of logging level. See module description for
 307 # details on that.
 308 #
 309 # Message to syslog is sent with tag @c dracut. Priorities are mapped as
 310 # following:
 311 #   - @c FATAL to @c crit
 312 #   - @c ERROR to @c error
 313 #   - @c WARN to @c warning
 314 #   - @c INFO to @c info
 315 #   - @c DEBUG and @c TRACE both to @c debug
 316 _do_dlog() {
 317     local lvl="$1"; shift
 318     local lvlc=$(_lvl2char "$lvl") || return 0
 319     local msg="$*"
 320     local lmsg="$lvlc: $*"
 321
 322     (( $lvl <= $stdloglvl )) && echo "$msg" >&2
 323     if (( $lvl <= $sysloglvl )); then
 324         logger -t "dracut[$$]" -p $(_lvl2syspri $lvl) "$msg"
 325     fi
 326
 327     if (( $lvl <= $fileloglvl )) && [[ -w "$logfile" ]] && [[ -f "$logfile" ]]; then
 328         echo "$lmsg" >>"$logfile"
 329     fi
 330
 331     if (( $lvl <= $fileloglvl )) && [[ "$_dlogfd" ]]; then
 332         echo "<$(_dlvl2syslvl $lvl)>$msg" >&$_dlogfd
 333     fi
 334
 335     (( $lvl <= $kmsgloglvl )) && \
 336         echo "<$(_dlvl2syslvl $lvl)>dracut[$$] $msg" >/dev/kmsg
 337 }
 338
 339 ## @brief Internal helper function for _do_dlog()
 340 #
 341 # @param lvl Numeric logging level.
 342 # @param msg Message.
 343 # @retval 0 It's always returned, even if logging failed.
 344 #
 345 # @note This function is not supposed to be called manually. Please use
 346 # dtrace(), ddebug(), or others instead which wrap this one.
 347 #
 348 # This function calls _do_dlog() either with parameter msg, or if
 349 # none is given, it will read standard input and will use every line as
 350 # a message.
 351 #
 352 # This enables:
 353 # dwarn "This is a warning"
 354 # echo "This is a warning" | dwarn
 355 dlog() {
 356     [ -z "$maxloglvl" ] && return 0
 357     (( $1 <= $maxloglvl )) || return 0
 358
 359     if (( $# > 1 )); then
 360         _do_dlog "$@"
 361     else
 362         while read line; do
 363             _do_dlog "$1" "$line"
 364         done
 365     fi
 366 }
 367
 368 ## @brief Logs message at TRACE level (6)
 369 #
 370 # @param msg Message.
 371 # @retval 0 It's always returned, even if logging failed.
 372 dtrace() {
 373     set +x
 374     dlog 6 "$@"
 375     [ -n "$debug" ] && set -x || :
 376 }
 377
 378 ## @brief Logs message at DEBUG level (5)
 379 #
 380 # @param msg Message.
 381 # @retval 0 It's always returned, even if logging failed.
 382 ddebug() {
 383     set +x
 384     dlog 5 "$@"
 385     [ -n "$debug" ] && set -x || :
 386 }
 387
 388 ## @brief Logs message at INFO level (4)
 389 #
 390 # @param msg Message.
 391 # @retval 0 It's always returned, even if logging failed.
 392 dinfo() {
 393     set +x
 394     dlog 4 "$@"
 395     [ -n "$debug" ] && set -x || :
 396 }
 397
 398 ## @brief Logs message at WARN level (3)
 399 #
 400 # @param msg Message.
 401 # @retval 0 It's always returned, even if logging failed.
 402 dwarn() {
 403     set +x
 404     dlog 3 "$@"
 405     [ -n "$debug" ] && set -x || :
 406 }
 407
 408 ## @brief It's an alias to dwarn() function.
 409 #
 410 # @param msg Message.
 411 # @retval 0 It's always returned, even if logging failed.
 412 dwarning() {
 413     set +x
 414     dwarn "$@"
 415     [ -n "$debug" ] && set -x || :
 416 }
 417
 418 ## @brief Logs message at ERROR level (2)
 419 #
 420 # @param msg Message.
 421 # @retval 0 It's always returned, even if logging failed.
 422 derror() {
 423     set +x
 424     dlog 2 "$@"
 425     [ -n "$debug" ] && set -x || :
 426 }
 427
 428 ## @brief Logs message at FATAL level (1)
 429 #
 430 # @param msg Message.
 431 # @retval 0 It's always returned, even if logging failed.
 432 dfatal() {
 433     set +x
 434     dlog 1 "$@"
 435     [ -n "$debug" ] && set -x || :
 436 }