dracut-logger.sh

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