Cleanup ZEDLETs

This commit factors out several common ZEDLET code blocks into
zed-functions.sh.  This shortens the length of the scripts, thereby
(hopefully) making them easier to understand and maintain.

In addition, this commit revamps the coding style used by the
scripts to be more consistent and (again, hopefully) maintainable.
It now mostly follows the Google Shell Style Guide.  I've tried to
assimilate the following resources:

  Google Shell Style Guide
  https://google-styleguide.googlecode.com/svn/trunk/shell.xml

  Dash as /bin/sh
  https://wiki.ubuntu.com/DashAsBinSh

  Filenames and Pathnames in Shell: How to do it Correctly
  http://www.dwheeler.com/essays/filenames-in-shell.html

  Common shell script mistakes
  http://www.pixelbeat.org/programming/shell_script_mistakes.html

Finally, this commit updates the exit codes used by the ZEDLETs to be
more consistent with one another.

All scripts run cleanly through ShellCheck <http://www.shellcheck.net/>.
All scripts have been tested on bash and dash.

Signed-off-by: Chris Dunlap <[email protected]>

1 files changed, 30 insertions, 58 deletions

diff --git a/cmd/zed/zed.d/data-email.sh b/cmd/zed/zed.d/data-email.sh
index 543b8fe55..2dae8ff6b 100755
--- a/cmd/zed/zed.d/data-email.sh
+++ b/cmd/zed/zed.d/data-email.sh
@@ -1,81 +1,53 @@
 #!/bin/sh
 #
-# Send email to ZED_EMAIL in response to a DATA zevent.
-# Only one message per ZED_EMAIL_INTERVAL_SECS will be sent for a given
-#   class/pool combination.  This protects against spamming the recipient
-#   should multiple events occur together in time for the same pool.
+# Send email to ZED_EMAIL in response to a DATA error.
+#
+# Only one email per ZED_EMAIL_INTERVAL_SECS will be sent for a given
+# class/pool combination.  This protects against spamming the recipient
+# should multiple events occur together in time for the same pool.
+#
 # Exit codes:
 #   0: email sent
 #   1: email failed
-#   2: email suppressed
-#   3: missing executable
-#   4: unsupported event class
-#   5: internal error
-# State File Format:
-#   POOL;TIME_OF_LAST_EMAIL
-#
-test -f "${ZED_ZEDLET_DIR}/zed.rc" && . "${ZED_ZEDLET_DIR}/zed.rc"
+#   2: email not configured
+#   3: email suppressed
+#   9: internal error
 
-test -n "${ZEVENT_POOL}" || exit 5
-test -n "${ZEVENT_SUBCLASS}" || exit 5
+[ -f "${ZED_ZEDLET_DIR}/zed.rc" ] && . "${ZED_ZEDLET_DIR}/zed.rc"
+. "${ZED_ZEDLET_DIR}/zed-functions.sh"
 
-if test "${ZEVENT_SUBCLASS}" != "data"; then \
-  logger -t "${ZED_SYSLOG_TAG:=zed}" \
-    -p "${ZED_SYSLOG_PRIORITY:=daemon.warning}" \
-    `basename "$0"`: unsupported event class \"${ZEVENT_SUBCLASS}\"
-  exit 4
-fi
+[ -n "${ZED_EMAIL}" ] || exit 2
 
-# Only send email if ZED_EMAIL has been configured.
-test -n "${ZED_EMAIL}" || exit 2
+[ -n "${ZEVENT_POOL}" ] || exit 9
+[ -n "${ZEVENT_SUBCLASS}" ] || exit 9
 
-# Ensure requisite executables are installed.
-if ! command -v "${MAIL:=mail}" >/dev/null 2>&1; then
-  logger -t "${ZED_SYSLOG_TAG:=zed}" \
-    -p "${ZED_SYSLOG_PRIORITY:=daemon.warning}" \
-    `basename "$0"`: "${MAIL}" not installed
-  exit 3
+if [ "${ZEVENT_SUBCLASS}" != "data" ]; then \
+    zed_log_err "unsupported event class \"${ZEVENT_SUBCLASS}\""
+    exit 9
 fi
 
-NAME="zed.${ZEVENT_SUBCLASS}.email"
-LOCKFILE="${ZED_LOCKDIR:=/var/lock}/${NAME}.lock"
-STATEFILE="${ZED_RUNDIR:=/var/run}/${NAME}.state"
+zed_check_cmd "mail" || exit 9
 
-# Obtain lock to ensure mutual exclusion for accessing state.
-exec 8> "${LOCKFILE}"
-flock -x 8
+zed_rate_limit "${ZEVENT_POOL};${ZEVENT_SUBCLASS};email" || exit 3
 
-# Query state for last time email was sent for this pool.
-TIME_NOW=`date +%s`
-TIME_LAST=`egrep "^${ZEVENT_POOL};" "${STATEFILE}" 2>/dev/null | cut -d ";" -f2`
-if test -n "${TIME_LAST}"; then
-  TIME_DELTA=`expr "${TIME_NOW}" - "${TIME_LAST}"`
-  if test "${TIME_DELTA}" -lt "${ZED_EMAIL_INTERVAL_SECS:=3600}"; then
-    exit 2
-  fi
-fi
-
-"${MAIL}" -s "ZFS ${ZEVENT_SUBCLASS} error for ${ZEVENT_POOL} on `hostname`" \
-  "${ZED_EMAIL}" <<EOF
+umask 077
+email_subject="ZFS ${ZEVENT_SUBCLASS} error for ${ZEVENT_POOL} on $(hostname)"
+email_pathname="${TMPDIR:="/tmp"}/$(basename -- "$0").${ZEVENT_EID}.$$"
+cat > "${email_pathname}" <<EOF
 A ZFS ${ZEVENT_SUBCLASS} error has been detected:
 
    eid: ${ZEVENT_EID}
-  host: `hostname`
+  host: $(hostname)
   time: ${ZEVENT_TIME_STRING}
   pool: ${ZEVENT_POOL}
 EOF
-MAIL_STATUS=$?
 
-# Update state.
-egrep -v "^${ZEVENT_POOL};" "${STATEFILE}" 2>/dev/null > "${STATEFILE}.$$"
-echo "${ZEVENT_POOL};${TIME_NOW}" >> "${STATEFILE}.$$"
-mv -f "${STATEFILE}.$$" "${STATEFILE}"
+mail -s "${email_subject}" "${ZED_EMAIL}" < "${email_pathname}"
+mail_status=$?
 
-if test "${MAIL_STATUS}" -ne 0; then
-  logger -t "${ZED_SYSLOG_TAG:=zed}" \
-    -p "${ZED_SYSLOG_PRIORITY:=daemon.warning}" \
-    `basename "$0"`: "${MAIL}" exit="${MAIL_STATUS}"
-  exit 1
+if [ "${mail_status}" -ne 0 ]; then
+    zed_log_msg "mail exit=${mail_status}"
+    exit 1
 fi
-
+rm -f "${email_pathname}"
 exit 0