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 _systemdcatfile="$DRACUT_TMPDIR/systemd-cat"
 152             mkfifo "$_systemdcatfile"
 153             readonly _dlogfd=15
 154             systemd-cat -t 'dracut' --level-prefix=true <"$_systemdcatfile" &
 155             exec 15>"$_systemdcatfile"
 156         elif ! [ -S /dev/log -a -w /dev/log ] || ! command -v logger >/dev/null; then
 157             # We cannot log to syslog, so turn this facility off.
 158             kmsgloglvl=$sysloglvl
 159             sysloglvl=0
 160             ret=1
 161             errmsg="No '/dev/log' or 'logger' included for syslog logging"
 162         fi
 163     fi
 164
 165     if (($sysloglvl > 0)) || (($kmsgloglvl > 0 )); then
 166         if [ -n "$dracutbasedir" ]; then
 167             readonly syslogfacility=user
 168         else
 169             readonly syslogfacility=daemon
 170         fi
 171         export syslogfacility
 172     fi
 173
 174     local lvl; local maxloglvl_l=0
 175     for lvl in $stdloglvl $sysloglvl $fileloglvl $kmsgloglvl; do
 176         (( $lvl > $maxloglvl_l )) && maxloglvl_l=$lvl
 177     done
 178     readonly maxloglvl=$maxloglvl_l
 179     export maxloglvl
 180
 181
 182     if (($stdloglvl < 6)) && (($kmsgloglvl < 6)) && (($fileloglvl < 6)) && (($sysloglvl < 6)); then
 183         unset dtrace
 184         dtrace() { :; };
 185     fi
 186
 187     if (($stdloglvl < 5)) && (($kmsgloglvl < 5)) && (($fileloglvl < 5)) && (($sysloglvl < 5)); then
 188         unset ddebug
 189         ddebug() { :; };
 190     fi
 191
 192     if (($stdloglvl < 4)) && (($kmsgloglvl < 4)) && (($fileloglvl < 4)) && (($sysloglvl < 4)); then
 193         unset dinfo
 194         dinfo() { :; };
 195     fi
 196
 197     if (($stdloglvl < 3)) && (($kmsgloglvl < 3)) && (($fileloglvl < 3)) && (($sysloglvl < 3)); then
 198         unset dwarn
 199         dwarn() { :; };
 200         unset dwarning
 201         dwarning() { :; };
 202     fi
 203
 204     if (($stdloglvl < 2)) && (($kmsgloglvl < 2)) && (($fileloglvl < 2)) && (($sysloglvl < 2)); then
 205         unset derror
 206         derror() { :; };
 207     fi
 208
 209     if (($stdloglvl < 1)) && (($kmsgloglvl < 1)) && (($fileloglvl < 1)) && (($sysloglvl < 1)); then
 210         unset dfatal
 211         dfatal() { :; };
 212     fi
 213
 214     [ -n "$errmsg" ] && derror "$errmsg"
 215
 216     return $ret
 217 }
 218
 219 ## @brief Converts numeric logging level to the first letter of level name.
 220 #
 221 # @param lvl Numeric logging level in range from 1 to 6.
 222 # @retval 1 if @a lvl is out of range.
 223 # @retval 0 if @a lvl is correct.
 224 # @result Echoes first letter of level name.
 225 _lvl2char() {
 226     case "$1" in
 227         1) echo F;;
 228         2) echo E;;
 229         3) echo W;;
 230         4) echo I;;
 231         5) echo D;;
 232         6) echo T;;
 233         *) return 1;;
 234     esac
 235 }
 236
 237 ## @brief Converts numeric level to logger priority defined by POSIX.2.
 238 #
 239 # @param lvl Numeric logging level in range from 1 to 6.
 240 # @retval 1 if @a lvl is out of range.
 241 # @retval 0 if @a lvl is correct.
 242 # @result Echoes logger priority.
 243 _lvl2syspri() {
 244     printf $syslogfacility.
 245     case "$1" in
 246         1) echo crit;;
 247         2) echo error;;
 248         3) echo warning;;
 249         4) echo info;;
 250         5) echo debug;;
 251         6) echo debug;;
 252         *) return 1;;
 253     esac
 254 }
 255
 256 ## @brief Converts dracut-logger numeric level to syslog log level
 257 #
 258 # @param lvl Numeric logging level in range from 1 to 6.
 259 # @retval 1 if @a lvl is out of range.
 260 # @retval 0 if @a lvl is correct.
 261 # @result Echoes kernel console numeric log level
 262 #
 263 # Conversion is done as follows:
 264 #
 265 # <tt>
 266 #   none     -> LOG_EMERG (0)
 267 #   none     -> LOG_ALERT (1)
 268 #   FATAL(1) -> LOG_CRIT (2)
 269 #   ERROR(2) -> LOG_ERR (3)
 270 #   WARN(3)  -> LOG_WARNING (4)
 271 #   none     -> LOG_NOTICE (5)
 272 #   INFO(4)  -> LOG_INFO (6)
 273 #   DEBUG(5) -> LOG_DEBUG (7)
 274 #   TRACE(6) /
 275 # </tt>
 276 #
 277 # @see /usr/include/sys/syslog.h
 278 _dlvl2syslvl() {
 279     local lvl
 280
 281     case "$1" in
 282         1) lvl=2;;
 283         2) lvl=3;;
 284         3) lvl=4;;
 285         4) lvl=6;;
 286         5) lvl=7;;
 287         6) lvl=7;;
 288         *) return 1;;
 289     esac
 290
 291     [ "$syslogfacility" = user ] && echo $((8+$lvl)) || echo $((24+$lvl))
 292 }
 293
 294 ## @brief Prints to stderr and/or writes to file, to syslog and/or /dev/kmsg
 295 # given message with given level (priority).
 296 #
 297 # @param lvl Numeric logging level.
 298 # @param msg Message.
 299 # @retval 0 It's always returned, even if logging failed.
 300 #
 301 # @note This function is not supposed to be called manually. Please use
 302 # dtrace(), ddebug(), or others instead which wrap this one.
 303 #
 304 # This is core logging function which logs given message to standard error, file
 305 # and/or syslog (with POSIX shell command <tt>logger</tt>) and/or to /dev/kmsg.
 306 # The format is following:
 307 #
 308 # <tt>X: some message</tt>
 309 #
 310 # where @c X is the first letter of logging level. See module description for
 311 # details on that.
 312 #
 313 # Message to syslog is sent with tag @c dracut. Priorities are mapped as
 314 # following:
 315 #   - @c FATAL to @c crit
 316 #   - @c ERROR to @c error
 317 #   - @c WARN to @c warning
 318 #   - @c INFO to @c info
 319 #   - @c DEBUG and @c TRACE both to @c debug
 320 _do_dlog() {
 321     local lvl="$1"; shift
 322     local lvlc=$(_lvl2char "$lvl") || return 0
 323     local msg="$*"
 324     local lmsg="$lvlc: $*"
 325
 326     (( $lvl <= $stdloglvl )) && printf -- 'dracut: %s\n' "$msg" >&2
 327
 328     if (( $lvl <= $sysloglvl )); then
 329         if [[ "$_dlogfd" ]]; then
 330             printf -- "<%s>%s\n" "$(($(_dlvl2syslvl $lvl) & 7))" "$msg" >&$_dlogfd
 331         else
 332             logger -t "dracut[$$]" -p $(_lvl2syspri $lvl) -- "$msg"
 333         fi
 334     fi
 335
 336     if (( $lvl <= $fileloglvl )) && [[ -w "$logfile" ]] && [[ -f "$logfile" ]]; then
 337         echo "$lmsg" >>"$logfile"
 338     fi
 339
 340     (( $lvl <= $kmsgloglvl )) && \
 341         echo "<$(_dlvl2syslvl $lvl)>dracut[$$] $msg" >/dev/kmsg
 342 }
 343
 344 ## @brief Internal helper function for _do_dlog()
 345 #
 346 # @param lvl Numeric logging level.
 347 # @param msg Message.
 348 # @retval 0 It's always returned, even if logging failed.
 349 #
 350 # @note This function is not supposed to be called manually. Please use
 351 # dtrace(), ddebug(), or others instead which wrap this one.
 352 #
 353 # This function calls _do_dlog() either with parameter msg, or if
 354 # none is given, it will read standard input and will use every line as
 355 # a message.
 356 #
 357 # This enables:
 358 # dwarn "This is a warning"
 359 # echo "This is a warning" | dwarn
 360 dlog() {
 361     [ -z "$maxloglvl" ] && return 0
 362     (( $1 <= $maxloglvl )) || return 0
 363
 364     if (( $# > 1 )); then
 365         _do_dlog "$@"
 366     else
 367         while read line || [ -n "$line" ]; do
 368             _do_dlog "$1" "$line"
 369         done
 370     fi
 371 }
 372
 373 ## @brief Logs message at TRACE level (6)
 374 #
 375 # @param msg Message.
 376 # @retval 0 It's always returned, even if logging failed.
 377 dtrace() {
 378     set +x
 379     dlog 6 "$@"
 380     [ -n "$debug" ] && set -x || :
 381 }
 382
 383 ## @brief Logs message at DEBUG level (5)
 384 #
 385 # @param msg Message.
 386 # @retval 0 It's always returned, even if logging failed.
 387 ddebug() {
 388     set +x
 389     dlog 5 "$@"
 390     [ -n "$debug" ] && set -x || :
 391 }
 392
 393 ## @brief Logs message at INFO level (4)
 394 #
 395 # @param msg Message.
 396 # @retval 0 It's always returned, even if logging failed.
 397 dinfo() {
 398     set +x
 399     dlog 4 "$@"
 400     [ -n "$debug" ] && set -x || :
 401 }
 402
 403 ## @brief Logs message at WARN level (3)
 404 #
 405 # @param msg Message.
 406 # @retval 0 It's always returned, even if logging failed.
 407 dwarn() {
 408     set +x
 409     dlog 3 "$@"
 410     [ -n "$debug" ] && set -x || :
 411 }
 412
 413 ## @brief It's an alias to dwarn() function.
 414 #
 415 # @param msg Message.
 416 # @retval 0 It's always returned, even if logging failed.
 417 dwarning() {
 418     set +x
 419     dwarn "$@"
 420     [ -n "$debug" ] && set -x || :
 421 }
 422
 423 ## @brief Logs message at ERROR level (2)
 424 #
 425 # @param msg Message.
 426 # @retval 0 It's always returned, even if logging failed.
 427 derror() {
 428     set +x
 429     dlog 2 "$@"
 430     [ -n "$debug" ] && set -x || :
 431 }
 432
 433 ## @brief Logs message at FATAL level (1)
 434 #
 435 # @param msg Message.
 436 # @retval 0 It's always returned, even if logging failed.
 437 dfatal() {
 438     set +x
 439     dlog 1 "$@"
 440     [ -n "$debug" ] && set -x || :
 441 }