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 export __DRACUT_LOGGER__=1
  21
  22 ## @brief Logging facility module for dracut both at build- and boot-time.
  23 #
  24 # @section intro Introduction
  25 #
  26 # The logger takes a bit from Log4j philosophy. There are defined 6 logging
  27 # levels:
  28 #   - TRACE (6)
  29 #     The TRACE Level designates finer-grained informational events than the
  30 #     DEBUG.
  31 #   - DEBUG (5)
  32 #     The DEBUG Level designates fine-grained informational events that are most
  33 #     useful to debug an application.
  34 #   - INFO (4)
  35 #     The INFO level designates informational messages that highlight the
  36 #     progress of the application at coarse-grained level.
  37 #   - WARN (3)
  38 #     The WARN level designates potentially harmful situations.
  39 #   - ERROR (2)
  40 #     The ERROR level designates error events that might still allow the
  41 #     application to continue running.
  42 #   - FATAL (1)
  43 #     The FATAL level designates very severe error events that will presumably
  44 #     lead the application to abort.
  45 # Descriptions are borrowed from Log4j documentation:
  46 # http://logging.apache.org/log4j/1.2/apidocs/org/apache/log4j/Level.html
  47 #
  48 # @section usage Usage
  49 #
  50 # First of all you have to start with dlog_init() function which initializes
  51 # required variables. Don't call any other logging function before that one!
  52 # If you're ready with this, you can use following functions which corresponds
  53 # clearly to levels listed in @ref intro Introduction. Here they are:
  54 #   - dtrace()
  55 #   - ddebug()
  56 #   - dinfo()
  57 #   - dwarn()
  58 #   - derror()
  59 #   - dfatal()
  60 # They take all arguments given as a single message to be logged. See dlog()
  61 # function for details how it works. Note that you shouldn't use dlog() by
  62 # yourself. It's wrapped with above functions.
  63 #
  64 # @see dlog_init() dlog()
  65 #
  66 # @section conf Configuration
  67 #
  68 # Logging is controlled by following global variables:
  69 #   - @var stdloglvl - logging level to standard error (console output)
  70 #   - @var sysloglvl - logging level to syslog (by logger command)
  71 #   - @var fileloglvl - logging level to file
  72 #   - @var kmsgloglvl - logging level to /dev/kmsg (only for boot-time)
  73 #   - @var logfile - log file which is used when @var fileloglvl is higher
  74 #   than 0
  75 # and two global variables: @var maxloglvl and @var syslogfacility which <b>must
  76 # not</b> be overwritten. Both are set by dlog_init(). @var maxloglvl holds
  77 # maximum logging level of those three and indicates that dlog_init() was run.
  78 # @var syslogfacility is set either to 'user' (when building initramfs) or
  79 # 'daemon' (when booting).
  80 #
  81 # Logging level set by the variable means that messages from this logging level
  82 # and above (FATAL is the highest) will be shown. Logging levels may be set
  83 # independently for each destination (stderr, syslog, file, kmsg).
  84 #
  85 # @see dlog_init()
  86
  87 ## @brief Initializes dracut Logger.
  88 #
  89 # @retval 1 if something has gone wrong
  90 # @retval 0 on success.
  91 #
  92 # @note This function need to be called before any other from this file.
  93 #
  94 # If any of the variables is not set, this function set it to default:
  95 #   - @var stdloglvl = 4 (info)
  96 #   - @var sysloglvl = 0 (no logging)
  97 #   - @var fileloglvl is set to 4 when @var logfile is set too, otherwise it's
  98 #   - @var kmsgloglvl = 0 (no logging)
  99 #   set to 0
 100 #
 101 # @warning Function sets global variables @var maxloglvl and @syslogfacility.
 102 # See file doc comment for details.
 103 dlog_init() {
 104     local __oldumask
 105     local ret=0
 106     local errmsg
 107     [ -z "$stdloglvl" ] && stdloglvl=4
 108     [ -z "$sysloglvl" ] && sysloglvl=0
 109     [ -z "$kmsgloglvl" ] && kmsgloglvl=0
 110     # Skip initialization if it's already done.
 111     [ -n "$maxloglvl" ] && return 0
 112
 113     if [ -z "$fileloglvl" ]; then
 114         [ -w "$logfile" ] && fileloglvl=4 || fileloglvl=0
 115     elif ((fileloglvl > 0)); then
 116         if [[ $logfile ]]; then
 117             __oldumask=$(umask)
 118             umask 0377
 119             ! [ -e "$logfile" ] && : > "$logfile"
 120             umask "$__oldumask"
 121             if [[ -w $logfile ]] && [[ -f $logfile ]]; then
 122                 # Mark new run in the log file
 123                 echo >> "$logfile"
 124                 if command -v date > /dev/null; then
 125                     echo "=== $(date) ===" >> "$logfile"
 126                 else
 127                     echo "===============================================" >> "$logfile"
 128                 fi
 129                 echo >> "$logfile"
 130             else
 131                 # We cannot log to file, so turn this facility off.
 132                 fileloglvl=0
 133                 ret=1
 134                 errmsg="'$logfile' is not a writable file"
 135             fi
 136         fi
 137     fi
 138
 139     if ((UID != 0)); then
 140         kmsgloglvl=0
 141         sysloglvl=0
 142     fi
 143
 144     if ((sysloglvl > 0)); then
 145         if [[ -d /run/systemd/journal ]] \
 146             && type -P systemd-cat &> /dev/null \
 147             && systemctl --quiet is-active systemd-journald.socket &> /dev/null \
 148             && { echo "dracut-$DRACUT_VERSION" | systemd-cat -t 'dracut' &> /dev/null; }; then
 149             readonly _systemdcatfile="$DRACUT_TMPDIR/systemd-cat"
 150             mkfifo "$_systemdcatfile"
 151             readonly _dlogfd=15
 152             systemd-cat -t 'dracut' --level-prefix=true < "$_systemdcatfile" &
 153             exec 15> "$_systemdcatfile"
 154         elif ! ([[ -S /dev/log ]] && [[ -w /dev/log ]] && command -v logger > /dev/null); then
 155             # We cannot log to syslog, so turn this facility off.
 156             kmsgloglvl=$sysloglvl
 157             sysloglvl=0
 158             ret=1
 159             errmsg="No '/dev/log' or 'logger' included for syslog logging"
 160         fi
 161     fi
 162
 163     if ((sysloglvl > 0)) || ((kmsgloglvl > 0)); then
 164         if [ -n "$dracutbasedir" ]; then
 165             readonly syslogfacility=user
 166         else
 167             readonly syslogfacility=daemon
 168         fi
 169         export syslogfacility
 170     fi
 171
 172     local lvl
 173     local maxloglvl_l=0
 174     for lvl in $stdloglvl $sysloglvl $fileloglvl $kmsgloglvl; do
 175         ((lvl > maxloglvl_l)) && maxloglvl_l=$lvl
 176     done
 177     readonly maxloglvl=$maxloglvl_l
 178     export maxloglvl
 179
 180     if ((stdloglvl < 6)) && ((kmsgloglvl < 6)) && ((fileloglvl < 6)) && ((sysloglvl < 6)); then
 181         unset dtrace
 182         dtrace() { :; }
 183     fi
 184
 185     if ((stdloglvl < 5)) && ((kmsgloglvl < 5)) && ((fileloglvl < 5)) && ((sysloglvl < 5)); then
 186         unset ddebug
 187         ddebug() { :; }
 188     fi
 189
 190     if ((stdloglvl < 4)) && ((kmsgloglvl < 4)) && ((fileloglvl < 4)) && ((sysloglvl < 4)); then
 191         unset dinfo
 192         dinfo() { :; }
 193     fi
 194
 195     if ((stdloglvl < 3)) && ((kmsgloglvl < 3)) && ((fileloglvl < 3)) && ((sysloglvl < 3)); then
 196         unset dwarn
 197         dwarn() { :; }
 198         unset dwarning
 199         dwarning() { :; }
 200     fi
 201
 202     if ((stdloglvl < 2)) && ((kmsgloglvl < 2)) && ((fileloglvl < 2)) && ((sysloglvl < 2)); then
 203         unset derror
 204         derror() { :; }
 205     fi
 206
 207     if ((stdloglvl < 1)) && ((kmsgloglvl < 1)) && ((fileloglvl < 1)) && ((sysloglvl < 1)); then
 208         unset dfatal
 209         dfatal() { :; }
 210     fi
 211
 212     [ -n "$errmsg" ] && derror "$errmsg"
 213
 214     return $ret
 215 }
 216
 217 ## @brief Converts numeric logging level to the first letter of level name.
 218 #
 219 # @param lvl Numeric logging level in range from 1 to 6.
 220 # @retval 1 if @a lvl is out of range.
 221 # @retval 0 if @a lvl is correct.
 222 # @result Echoes first letter of level name.
 223 _lvl2char() {
 224     case "$1" in
 225         1) echo F ;;
 226         2) echo E ;;
 227         3) echo W ;;
 228         4) echo I ;;
 229         5) echo D ;;
 230         6) echo T ;;
 231         *) return 1 ;;
 232     esac
 233 }
 234
 235 ## @brief Converts numeric level to logger priority defined by POSIX.2.
 236 #
 237 # @param lvl Numeric logging level in range from 1 to 6.
 238 # @retval 1 if @a lvl is out of range.
 239 # @retval 0 if @a lvl is correct.
 240 # @result Echoes logger priority.
 241 _lvl2syspri() {
 242     printf -- "%s" "$syslogfacility."
 243     case "$1" in
 244         1) echo crit ;;
 245         2) echo error ;;
 246         3) echo warning ;;
 247         4) echo info ;;
 248         5) echo debug ;;
 249         6) echo debug ;;
 250         *) return 1 ;;
 251     esac
 252 }
 253
 254 ## @brief Converts dracut-logger numeric level to syslog log level
 255 #
 256 # @param lvl Numeric logging level in range from 1 to 6.
 257 # @retval 1 if @a lvl is out of range.
 258 # @retval 0 if @a lvl is correct.
 259 # @result Echoes kernel console numeric log level
 260 #
 261 # Conversion is done as follows:
 262 #
 263 # <tt>
 264 #   none     -> LOG_EMERG (0)
 265 #   none     -> LOG_ALERT (1)
 266 #   FATAL(1) -> LOG_CRIT (2)
 267 #   ERROR(2) -> LOG_ERR (3)
 268 #   WARN(3)  -> LOG_WARNING (4)
 269 #   none     -> LOG_NOTICE (5)
 270 #   INFO(4)  -> LOG_INFO (6)
 271 #   DEBUG(5) -> LOG_DEBUG (7)
 272 #   TRACE(6) /
 273 # </tt>
 274 #
 275 # @see /usr/include/sys/syslog.h
 276 _dlvl2syslvl() {
 277     local lvl
 278
 279     case "$1" in
 280         1) lvl=2 ;;
 281         2) lvl=3 ;;
 282         3) lvl=4 ;;
 283         4) lvl=6 ;;
 284         5) lvl=7 ;;
 285         6) lvl=7 ;;
 286         *) return 1 ;;
 287     esac
 288
 289     [ "$syslogfacility" = user ] && echo $((8 + lvl)) || echo $((24 + lvl))
 290 }
 291
 292 ## @brief Prints to stderr and/or writes to file, to syslog and/or /dev/kmsg
 293 # given message with given level (priority).
 294 #
 295 # @param lvl Numeric logging level.
 296 # @param msg Message.
 297 # @retval 0 It's always returned, even if logging failed.
 298 #
 299 # @note This function is not supposed to be called manually. Please use
 300 # dtrace(), ddebug(), or others instead which wrap this one.
 301 #
 302 # This is core logging function which logs given message to standard error, file
 303 # and/or syslog (with POSIX shell command <tt>logger</tt>) and/or to /dev/kmsg.
 304 # The format is following:
 305 #
 306 # <tt>X: some message</tt>
 307 #
 308 # where @c X is the first letter of logging level. See module description for
 309 # details on that.
 310 #
 311 # Message to syslog is sent with tag @c dracut. Priorities are mapped as
 312 # following:
 313 #   - @c FATAL to @c crit
 314 #   - @c ERROR to @c error
 315 #   - @c WARN to @c warning
 316 #   - @c INFO to @c info
 317 #   - @c DEBUG and @c TRACE both to @c debug
 318 _do_dlog() {
 319     local lvlc
 320     local lvl="$1"
 321     shift
 322     lvlc=$(_lvl2char "$lvl") || return 0
 323     local msg="$*"
 324     local lmsg="$lvlc: $*"
 325
 326     ((lvl <= stdloglvl)) && printf -- 'dracut[%s]: %s\n' "$lvlc" "$msg" >&2
 327
 328     if ((lvl <= sysloglvl)); then
 329         if [[ "$_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 "$@"
 366     else
 367         while read -r line || [ -n "$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 "$@"
 380     if [ -n "$debug" ]; then
 381         set -x
 382     fi
 383 }
 384
 385 ## @brief Logs message at DEBUG level (5)
 386 #
 387 # @param msg Message.
 388 # @retval 0 It's always returned, even if logging failed.
 389 ddebug() {
 390     set +x
 391     dlog 5 "$@"
 392     if [ -n "$debug" ]; then
 393         set -x
 394     fi
 395 }
 396
 397 ## @brief Logs message at INFO level (4)
 398 #
 399 # @param msg Message.
 400 # @retval 0 It's always returned, even if logging failed.
 401 dinfo() {
 402     set +x
 403     dlog 4 "$@"
 404     if [ -n "$debug" ]; then
 405         set -x
 406     fi
 407 }
 408
 409 ## @brief Logs message at WARN level (3)
 410 #
 411 # @param msg Message.
 412 # @retval 0 It's always returned, even if logging failed.
 413 dwarn() {
 414     set +x
 415     dlog 3 "$@"
 416     if [ -n "$debug" ]; then
 417         set -x
 418     fi
 419 }
 420
 421 ## @brief It's an alias to dwarn() function.
 422 #
 423 # @param msg Message.
 424 # @retval 0 It's always returned, even if logging failed.
 425 dwarning() {
 426     set +x
 427     dwarn "$@"
 428     if [ -n "$debug" ]; then
 429         set -x
 430     fi
 431 }
 432
 433 ## @brief Logs message at ERROR level (2)
 434 #
 435 # @param msg Message.
 436 # @retval 0 It's always returned, even if logging failed.
 437 derror() {
 438     set +x
 439     dlog 2 "$@"
 440     if [ -n "$debug" ]; then
 441         set -x
 442     fi
 443 }
 444
 445 ## @brief Logs message at FATAL level (1)
 446 #
 447 # @param msg Message.
 448 # @retval 0 It's always returned, even if logging failed.
 449 dfatal() {
 450     set +x
 451     dlog 1 "$@"
 452     if [ -n "$debug" ]; then
 453         set -x
 454     fi
 455 }