1#!/bin/sh 2# shellcheck disable=SC2039 3# zed-functions.sh 4# 5# ZED helper functions for use in ZEDLETs 6 7 8# Variable Defaults 9# 10: "${ZED_LOCKDIR:="/var/lock"}" 11: "${ZED_NOTIFY_INTERVAL_SECS:=3600}" 12: "${ZED_NOTIFY_VERBOSE:=0}" 13: "${ZED_RUNDIR:="/var/run"}" 14: "${ZED_SYSLOG_PRIORITY:="daemon.notice"}" 15: "${ZED_SYSLOG_TAG:="zed"}" 16 17ZED_FLOCK_FD=8 18 19 20# zed_check_cmd (cmd, ...) 21# 22# For each argument given, search PATH for the executable command [cmd]. 23# Log a message if [cmd] is not found. 24# 25# Arguments 26# cmd: name of executable command for which to search 27# 28# Return 29# 0 if all commands are found in PATH and are executable 30# n for a count of the command executables that are not found 31# 32zed_check_cmd() 33{ 34 local cmd 35 local rv=0 36 37 for cmd; do 38 if ! command -v "${cmd}" >/dev/null 2>&1; then 39 zed_log_err "\"${cmd}\" not installed" 40 rv=$((rv + 1)) 41 fi 42 done 43 return "${rv}" 44} 45 46 47# zed_log_msg (msg, ...) 48# 49# Write all argument strings to the system log. 50# 51# Globals 52# ZED_SYSLOG_PRIORITY 53# ZED_SYSLOG_TAG 54# 55# Return 56# nothing 57# 58zed_log_msg() 59{ 60 logger -p "${ZED_SYSLOG_PRIORITY}" -t "${ZED_SYSLOG_TAG}" -- "$@" 61} 62 63 64# zed_log_err (msg, ...) 65# 66# Write an error message to the system log. This message will contain the 67# script name, EID, and all argument strings. 68# 69# Globals 70# ZED_SYSLOG_PRIORITY 71# ZED_SYSLOG_TAG 72# ZEVENT_EID 73# 74# Return 75# nothing 76# 77zed_log_err() 78{ 79 logger -p "${ZED_SYSLOG_PRIORITY}" -t "${ZED_SYSLOG_TAG}" -- "error:" \ 80 "$(basename -- "$0"):""${ZEVENT_EID:+" eid=${ZEVENT_EID}:"}" "$@" 81} 82 83 84# zed_lock (lockfile, [fd]) 85# 86# Obtain an exclusive (write) lock on [lockfile]. If the lock cannot be 87# immediately acquired, wait until it becomes available. 88# 89# Every zed_lock() must be paired with a corresponding zed_unlock(). 90# 91# By default, flock-style locks associate the lockfile with file descriptor 8. 92# The bash manpage warns that file descriptors >9 should be used with care as 93# they may conflict with file descriptors used internally by the shell. File 94# descriptor 9 is reserved for zed_rate_limit(). If concurrent locks are held 95# within the same process, they must use different file descriptors (preferably 96# decrementing from 8); otherwise, obtaining a new lock with a given file 97# descriptor will release the previous lock associated with that descriptor. 98# 99# Arguments 100# lockfile: pathname of the lock file; the lock will be stored in 101# ZED_LOCKDIR unless the pathname contains a "/". 102# fd: integer for the file descriptor used by flock (OPTIONAL unless holding 103# concurrent locks) 104# 105# Globals 106# ZED_FLOCK_FD 107# ZED_LOCKDIR 108# 109# Return 110# nothing 111# 112zed_lock() 113{ 114 local lockfile="$1" 115 local fd="${2:-${ZED_FLOCK_FD}}" 116 local umask_bak 117 local err 118 119 [ -n "${lockfile}" ] || return 120 if ! expr "${lockfile}" : '.*/' >/dev/null 2>&1; then 121 lockfile="${ZED_LOCKDIR}/${lockfile}" 122 fi 123 124 umask_bak="$(umask)" 125 umask 077 126 127 # Obtain a lock on the file bound to the given file descriptor. 128 # 129 eval "exec ${fd}>> '${lockfile}'" 130 if ! err="$(flock --exclusive "${fd}" 2>&1)"; then 131 zed_log_err "failed to lock \"${lockfile}\": ${err}" 132 fi 133 134 umask "${umask_bak}" 135} 136 137 138# zed_unlock (lockfile, [fd]) 139# 140# Release the lock on [lockfile]. 141# 142# Arguments 143# lockfile: pathname of the lock file 144# fd: integer for the file descriptor used by flock (must match the file 145# descriptor passed to the zed_lock function call) 146# 147# Globals 148# ZED_FLOCK_FD 149# ZED_LOCKDIR 150# 151# Return 152# nothing 153# 154zed_unlock() 155{ 156 local lockfile="$1" 157 local fd="${2:-${ZED_FLOCK_FD}}" 158 local err 159 160 [ -n "${lockfile}" ] || return 161 if ! expr "${lockfile}" : '.*/' >/dev/null 2>&1; then 162 lockfile="${ZED_LOCKDIR}/${lockfile}" 163 fi 164 165 # Release the lock and close the file descriptor. 166 if ! err="$(flock --unlock "${fd}" 2>&1)"; then 167 zed_log_err "failed to unlock \"${lockfile}\": ${err}" 168 fi 169 eval "exec ${fd}>&-" 170} 171 172 173# zed_notify (subject, pathname) 174# 175# Send a notification via all available methods. 176# 177# Arguments 178# subject: notification subject 179# pathname: pathname containing the notification message (OPTIONAL) 180# 181# Return 182# 0: notification succeeded via at least one method 183# 1: notification failed 184# 2: no notification methods configured 185# 186zed_notify() 187{ 188 local subject="$1" 189 local pathname="$2" 190 local num_success=0 191 local num_failure=0 192 193 zed_notify_email "${subject}" "${pathname}"; rv=$? 194 [ "${rv}" -eq 0 ] && num_success=$((num_success + 1)) 195 [ "${rv}" -eq 1 ] && num_failure=$((num_failure + 1)) 196 197 zed_notify_pushbullet "${subject}" "${pathname}"; rv=$? 198 [ "${rv}" -eq 0 ] && num_success=$((num_success + 1)) 199 [ "${rv}" -eq 1 ] && num_failure=$((num_failure + 1)) 200 201 zed_notify_slack_webhook "${subject}" "${pathname}"; rv=$? 202 [ "${rv}" -eq 0 ] && num_success=$((num_success + 1)) 203 [ "${rv}" -eq 1 ] && num_failure=$((num_failure + 1)) 204 205 [ "${num_success}" -gt 0 ] && return 0 206 [ "${num_failure}" -gt 0 ] && return 1 207 return 2 208} 209 210 211# zed_notify_email (subject, pathname) 212# 213# Send a notification via email to the address specified by ZED_EMAIL_ADDR. 214# 215# Requires the mail executable to be installed in the standard PATH, or 216# ZED_EMAIL_PROG to be defined with the pathname of an executable capable of 217# reading a message body from stdin. 218# 219# Command-line options to the mail executable can be specified in 220# ZED_EMAIL_OPTS. This undergoes the following keyword substitutions: 221# - @ADDRESS@ is replaced with the space-delimited recipient email address(es) 222# - @SUBJECT@ is replaced with the notification subject 223# 224# Arguments 225# subject: notification subject 226# pathname: pathname containing the notification message (OPTIONAL) 227# 228# Globals 229# ZED_EMAIL_PROG 230# ZED_EMAIL_OPTS 231# ZED_EMAIL_ADDR 232# 233# Return 234# 0: notification sent 235# 1: notification failed 236# 2: not configured 237# 238zed_notify_email() 239{ 240 local subject="$1" 241 local pathname="${2:-"/dev/null"}" 242 243 : "${ZED_EMAIL_PROG:="mail"}" 244 : "${ZED_EMAIL_OPTS:="-s '@SUBJECT@' @ADDRESS@"}" 245 246 # For backward compatibility with ZED_EMAIL. 247 if [ -n "${ZED_EMAIL}" ] && [ -z "${ZED_EMAIL_ADDR}" ]; then 248 ZED_EMAIL_ADDR="${ZED_EMAIL}" 249 fi 250 [ -n "${ZED_EMAIL_ADDR}" ] || return 2 251 252 zed_check_cmd "${ZED_EMAIL_PROG}" || return 1 253 254 [ -n "${subject}" ] || return 1 255 if [ ! -r "${pathname}" ]; then 256 zed_log_err \ 257 "$(basename "${ZED_EMAIL_PROG}") cannot read \"${pathname}\"" 258 return 1 259 fi 260 261 ZED_EMAIL_OPTS="$(echo "${ZED_EMAIL_OPTS}" \ 262 | sed -e "s/@ADDRESS@/${ZED_EMAIL_ADDR}/g" \ 263 -e "s/@SUBJECT@/${subject}/g")" 264 265 # shellcheck disable=SC2086 266 ${ZED_EMAIL_PROG} ${ZED_EMAIL_OPTS} < "${pathname}" >/dev/null 2>&1 267 rv=$? 268 if [ "${rv}" -ne 0 ]; then 269 zed_log_err "$(basename "${ZED_EMAIL_PROG}") exit=${rv}" 270 return 1 271 fi 272 return 0 273} 274 275 276# zed_notify_pushbullet (subject, pathname) 277# 278# Send a notification via Pushbullet <https://www.pushbullet.com/>. 279# The access token (ZED_PUSHBULLET_ACCESS_TOKEN) identifies this client to the 280# Pushbullet server. The optional channel tag (ZED_PUSHBULLET_CHANNEL_TAG) is 281# for pushing to notification feeds that can be subscribed to; if a channel is 282# not defined, push notifications will instead be sent to all devices 283# associated with the account specified by the access token. 284# 285# Requires awk, curl, and sed executables to be installed in the standard PATH. 286# 287# References 288# https://docs.pushbullet.com/ 289# https://www.pushbullet.com/security 290# 291# Arguments 292# subject: notification subject 293# pathname: pathname containing the notification message (OPTIONAL) 294# 295# Globals 296# ZED_PUSHBULLET_ACCESS_TOKEN 297# ZED_PUSHBULLET_CHANNEL_TAG 298# 299# Return 300# 0: notification sent 301# 1: notification failed 302# 2: not configured 303# 304zed_notify_pushbullet() 305{ 306 local subject="$1" 307 local pathname="${2:-"/dev/null"}" 308 local msg_body 309 local msg_tag 310 local msg_json 311 local msg_out 312 local msg_err 313 local url="https://api.pushbullet.com/v2/pushes" 314 315 [ -n "${ZED_PUSHBULLET_ACCESS_TOKEN}" ] || return 2 316 317 [ -n "${subject}" ] || return 1 318 if [ ! -r "${pathname}" ]; then 319 zed_log_err "pushbullet cannot read \"${pathname}\"" 320 return 1 321 fi 322 323 zed_check_cmd "awk" "curl" "sed" || return 1 324 325 # Escape the following characters in the message body for JSON: 326 # newline, backslash, double quote, horizontal tab, vertical tab, 327 # and carriage return. 328 # 329 msg_body="$(awk '{ ORS="\\n" } { gsub(/\\/, "\\\\"); gsub(/"/, "\\\""); 330 gsub(/\t/, "\\t"); gsub(/\f/, "\\f"); gsub(/\r/, "\\r"); print }' \ 331 "${pathname}")" 332 333 # Push to a channel if one is configured. 334 # 335 [ -n "${ZED_PUSHBULLET_CHANNEL_TAG}" ] && msg_tag="$(printf \ 336 '"channel_tag": "%s", ' "${ZED_PUSHBULLET_CHANNEL_TAG}")" 337 338 # Construct the JSON message for pushing a note. 339 # 340 msg_json="$(printf '{%s"type": "note", "title": "%s", "body": "%s"}' \ 341 "${msg_tag}" "${subject}" "${msg_body}")" 342 343 # Send the POST request and check for errors. 344 # 345 msg_out="$(curl -u "${ZED_PUSHBULLET_ACCESS_TOKEN}:" -X POST "${url}" \ 346 --header "Content-Type: application/json" --data-binary "${msg_json}" \ 347 2>/dev/null)"; rv=$? 348 if [ "${rv}" -ne 0 ]; then 349 zed_log_err "curl exit=${rv}" 350 return 1 351 fi 352 msg_err="$(echo "${msg_out}" \ 353 | sed -n -e 's/.*"error" *:.*"message" *: *"\([^"]*\)".*/\1/p')" 354 if [ -n "${msg_err}" ]; then 355 zed_log_err "pushbullet \"${msg_err}"\" 356 return 1 357 fi 358 return 0 359} 360 361 362# zed_notify_slack_webhook (subject, pathname) 363# 364# Notification via Slack Webhook <https://api.slack.com/incoming-webhooks>. 365# The Webhook URL (ZED_SLACK_WEBHOOK_URL) identifies this client to the 366# Slack channel. 367# 368# Requires awk, curl, and sed executables to be installed in the standard PATH. 369# 370# References 371# https://api.slack.com/incoming-webhooks 372# 373# Arguments 374# subject: notification subject 375# pathname: pathname containing the notification message (OPTIONAL) 376# 377# Globals 378# ZED_SLACK_WEBHOOK_URL 379# 380# Return 381# 0: notification sent 382# 1: notification failed 383# 2: not configured 384# 385zed_notify_slack_webhook() 386{ 387 [ -n "${ZED_SLACK_WEBHOOK_URL}" ] || return 2 388 389 local subject="$1" 390 local pathname="${2:-"/dev/null"}" 391 local msg_body 392 local msg_tag 393 local msg_json 394 local msg_out 395 local msg_err 396 local url="${ZED_SLACK_WEBHOOK_URL}" 397 398 [ -n "${subject}" ] || return 1 399 if [ ! -r "${pathname}" ]; then 400 zed_log_err "slack webhook cannot read \"${pathname}\"" 401 return 1 402 fi 403 404 zed_check_cmd "awk" "curl" "sed" || return 1 405 406 # Escape the following characters in the message body for JSON: 407 # newline, backslash, double quote, horizontal tab, vertical tab, 408 # and carriage return. 409 # 410 msg_body="$(awk '{ ORS="\\n" } { gsub(/\\/, "\\\\"); gsub(/"/, "\\\""); 411 gsub(/\t/, "\\t"); gsub(/\f/, "\\f"); gsub(/\r/, "\\r"); print }' \ 412 "${pathname}")" 413 414 # Construct the JSON message for posting. 415 # 416 msg_json="$(printf '{"text": "*%s*\n%s"}' "${subject}" "${msg_body}" )" 417 418 # Send the POST request and check for errors. 419 # 420 msg_out="$(curl -X POST "${url}" \ 421 --header "Content-Type: application/json" --data-binary "${msg_json}" \ 422 2>/dev/null)"; rv=$? 423 if [ "${rv}" -ne 0 ]; then 424 zed_log_err "curl exit=${rv}" 425 return 1 426 fi 427 msg_err="$(echo "${msg_out}" \ 428 | sed -n -e 's/.*"error" *:.*"message" *: *"\([^"]*\)".*/\1/p')" 429 if [ -n "${msg_err}" ]; then 430 zed_log_err "slack webhook \"${msg_err}"\" 431 return 1 432 fi 433 return 0 434} 435 436# zed_rate_limit (tag, [interval]) 437# 438# Check whether an event of a given type [tag] has already occurred within the 439# last [interval] seconds. 440# 441# This function obtains a lock on the statefile using file descriptor 9. 442# 443# Arguments 444# tag: arbitrary string for grouping related events to rate-limit 445# interval: time interval in seconds (OPTIONAL) 446# 447# Globals 448# ZED_NOTIFY_INTERVAL_SECS 449# ZED_RUNDIR 450# 451# Return 452# 0 if the event should be processed 453# 1 if the event should be dropped 454# 455# State File Format 456# time;tag 457# 458zed_rate_limit() 459{ 460 local tag="$1" 461 local interval="${2:-${ZED_NOTIFY_INTERVAL_SECS}}" 462 local lockfile="zed.zedlet.state.lock" 463 local lockfile_fd=9 464 local statefile="${ZED_RUNDIR}/zed.zedlet.state" 465 local time_now 466 local time_prev 467 local umask_bak 468 local rv=0 469 470 [ -n "${tag}" ] || return 0 471 472 zed_lock "${lockfile}" "${lockfile_fd}" 473 time_now="$(date +%s)" 474 time_prev="$(grep -E "^[0-9]+;${tag}\$" "${statefile}" 2>/dev/null \ 475 | tail -1 | cut -d\; -f1)" 476 477 if [ -n "${time_prev}" ] \ 478 && [ "$((time_now - time_prev))" -lt "${interval}" ]; then 479 rv=1 480 else 481 umask_bak="$(umask)" 482 umask 077 483 grep -E -v "^[0-9]+;${tag}\$" "${statefile}" 2>/dev/null \ 484 > "${statefile}.$$" 485 echo "${time_now};${tag}" >> "${statefile}.$$" 486 mv -f "${statefile}.$$" "${statefile}" 487 umask "${umask_bak}" 488 fi 489 490 zed_unlock "${lockfile}" "${lockfile_fd}" 491 return "${rv}" 492} 493 494 495# zed_guid_to_pool (guid) 496# 497# Convert a pool GUID into its pool name (like "tank") 498# Arguments 499# guid: pool GUID (decimal or hex) 500# 501# Return 502# Pool name 503# 504zed_guid_to_pool() 505{ 506 if [ -z "$1" ] ; then 507 return 508 fi 509 510 guid="$(printf "%u" "$1")" 511 $ZPOOL get -H -ovalue,name guid | awk '$1 == '"$guid"' {print $2; exit}' 512} 513 514# zed_exit_if_ignoring_this_event 515# 516# Exit the script if we should ignore this event, as determined by 517# $ZED_SYSLOG_SUBCLASS_INCLUDE and $ZED_SYSLOG_SUBCLASS_EXCLUDE in zed.rc. 518# This function assumes you've imported the normal zed variables. 519zed_exit_if_ignoring_this_event() 520{ 521 if [ -n "${ZED_SYSLOG_SUBCLASS_INCLUDE}" ]; then 522 eval "case ${ZEVENT_SUBCLASS} in 523 ${ZED_SYSLOG_SUBCLASS_INCLUDE});; 524 *) exit 0;; 525 esac" 526 elif [ -n "${ZED_SYSLOG_SUBCLASS_EXCLUDE}" ]; then 527 eval "case ${ZEVENT_SUBCLASS} in 528 ${ZED_SYSLOG_SUBCLASS_EXCLUDE}) exit 0;; 529 *);; 530 esac" 531 fi 532} 533