--- badi/public_scripts/canardien/canardien	2013/06/26 00:13:44	1.3
+++ badi/public_scripts/canardien/canardien	2023/08/06 20:06:51	1.6
@@ -1,17 +1,22 @@
 #!/bin/bash
 
-# canardien 0.0.3
-# (c) 2005 under GPL by Adrian Zaugg
+# canardien 0.0.6
+# (c) 2005-2021 under GPL by Adrian Zaugg
 
-# canardiens pings ente.limmat.ch to determine wether she is gone diving.
 
-# ToDo: multi host, multi eMail
+# canardien [<host> [<host> ...]]
+
+# canardiens pings a machine, originally ente.limmat.ch thus its name,
+# to determine wether she is gone diving.
+
 
 ## Settings
 #
 
-# Host to ping. It's ente.limmat.ch
-HOST="ente.limmat.ch"
+# Hosts to ping. use a space separated list for multiple targets. All
+# hosts of the list are checked and their results reported individually.
+# Hosts given on the command line overwrite this setting.
+HOSTS=""
 
 # eMail Alerts
 # Send alert email messages to the following address(es). Leave empty
@@ -19,126 +24,181 @@ HOST="ente.limmat.ch"
 ALERT_TO="root"
 
 # Subject of alert email
-ALERT_SUBJECT="Attention: no answer from $HOST anymore!"
+ALERT_SUBJECT='"Attention: no answer from $HOST anymore!"'
 
-# Text of Message (But in 'single quotes' to protect variables. They should get
-# expanded at the time the message is sent!)
+# Text of Message (Put variables in 'single quotes' to protect them. They
+# should get expanded at the time the message is sent!)
 ALERT_TEXT='"\n[$TIME_STAMP]\n\nALERT!!\n\n\t$HOST is down!\n\nYou should probably do something, please.\n\nKind regards, $PINGHOST."'
 
-# path to fping
-PING=`which fping`
+# Path to fping
+PING=""
 
-# answer of fping to reachable hosts
+# Answer of fping to reachable hosts
 ALIVE_ANSWER="is alive"
 
+# Max number of pakets to send before giving up. Time increases exponentially,
+# use a number < 7.
+RETRIES=5
+
 # Temporary file path
 TMPDIR="/tmp"
 
 # This hosts name
-PINGHOST=`uname -n`
+PINGHOST="$(uname -n)"
 
-# set to an empty string to avoid debug output,
+# Set to an empty string to avoid debug output,
 # to "low" for a few, output and to anything else
 # for verbose output
-DEBUG=loud
+DEBUG=verbose
 
-# for silent (non-error) operation set to anything,
+# For silent (non-error) operation set to anything,
 # comment out to enable text output
-# (migration to use shout is in progress)
-SILENT=shshsh
+#SILENT=shshsh
 
 
 # -----------functions-----------
 
-# If ente.limmat.ch responds to pings, she is considered up.
-function checkconnection {
-   unset UP
+# Initialize.
+function init() {
+
+	# check fping existence
+	if [ -z "$PING" ]; then
+		PING="$(which fping)"
+	fi
 	if [ ${#PING} -eq 0 ]; then
-		echo "Error: fping external program not in path. Exitting."
+		echo "Error: fping external program not found or not set. Exitting." >&2
+		exit 1
+	fi
+	if [ ! -x "$PING" ]; then
+		echo "Error: Can't execute the program set to use as fping. Please enter the correct path to \"fping\"." >&2
 		exit 1
 	fi
 
-   PING_ANSWER="$($PING "$HOST")"
-   PING_ERRNUM=$?
-   if [ $PING_ERRNUM -gt 2 ]; then
-   		echo "Error $PING_ERRNUM in fping $(head -1 "$PING_ANSWER") . Exitting."
-   		exit 1
-   fi
-
-   if [ `echo "$PING_ANSWER" | grep -c "$ALIVE_ANSWER"` -gt 0 ]; then
-      UP=true
-   fi
-   TIME_STAMP=`date +"%a %e.%m.%y %H:%M:%S"`
-   if [ -n "$UP" ]; then
-      if [ ! "$DEBUG" = "low" ] && [ -n "$DEBUG"  ]; then
-         shout "The connection is up."
-      fi
-   else 
-      if [ -n "$DEBUG" ]; then
-         shout "The connection is down."
-      fi
-   fi
+	# get hostset
+	if [ -n "$*" ]; then
+		HOSTS="$*"
+	fi
+
+	# remove multiple spaces and trim
+	HOSTS="$(echo "$HOSTS" | sed -e "s/ \{1,\}/ /g" -e "s/^ //" -e "s/ $//")"
+
+	if [ -z "$HOSTS" ]; then
+		echo "Error: No host to ping." >&2
+		exit 1
+	fi
 }
 
-# Rember recent state of ente.limmat.ch, trigger alert
-function rememberstate {
-   # Put a simple time stamp in a tmp file, when host gets down
-   if [ -z "$UP" ]; then
-		if [ ! -e "$TMPDIR/.canardien-$PINGHOST-$HOST" ]; then 
-      		# set time stamp
-      		echo -ne "$TIME_STAMP" > "$TMPDIR/.canardien-$PINGHOST-$HOST"
-      		# send alert
-      		sendalert
-      	elif [ -n "$DEBUG" ]; then
-         	shout "Down since `cat $TMPDIR/.canardien-$PINGHOST-$HOST`."
-      	fi
-   else 
-     # Host is up
-      if [ -e "$TMPDIR/.canardien-$PINGHOST-$HOST" ]; then
-         if [ -n "$DEBUG" ]; then
-            shout "$HOST is up again."
-         fi
-		  # send alert
-          ALERT_SUBJECT="The host $HOST answers again!!"
-          ALERT_TEXT='"[$(date +"%a %e.%m.%y %H:%M:%S")]\n\n\n$HOST is up again.\n--------------------------------------\n(downtime began $(cat "$TMPDIR/.canardien-$PINGHOST-$HOST"))\n\n\n      Kind regards, $PINGHOST."'
-          sendalert
-         # delete tmp file
-         rm "$TMPDIR/.canardien-$PINGHOST-$HOST"
-      else 
-         # still running
-         if [ ! "$DEBUG" = "low" ] && [ -n "$DEBUG"  ]; then
-            shout "$HOST is still up."
-         fi
-      fi
-   fi
+
+# If a host responds to pings, it is considered up.
+function checkconnection() {
+
+	unset UP
+
+	# ping host
+	PING_ANSWER="$($PING -R -B 2 -r $RETRIES -p 50 "$HOST" 2>&1)"
+	PING_ERRNUM=$?
+	if [ $PING_ERRNUM -gt 2 ]; then
+		echo "Error: Got error $PING_ERRNUM from fping $(head -1 "$PING_ANSWER"). Disregarding $HOST." >&2
+		continue;
+	fi
+
+	# parse answer
+	if [ $(echo "$PING_ANSWER" | grep -c "$ALIVE_ANSWER") -gt 0 ]; then
+		UP=true
+	fi
+	TIME_STAMP="$(date +"%a %e.%m.%y %H:%M:%S")"
+	if [ -n "$UP" ]; then
+		if [ ! "$DEBUG" = "low" ] && [ -n "$DEBUG"  ]; then
+			shout "The connection to $HOST is up."
+		fi
+	else
+		if [ -n "$DEBUG" ]; then
+			shout "The connection to $HOST is down."
+		fi
+	fi
+
+	# remember a hosts state
+	rememberstate
+}
+
+
+# Rember recent state of host, trigger alert
+function rememberstate() {
+	# Put a simple time stamp in a tmp file, when host is detected as down for the first time
+	if [ -z "$UP" ]; then
+		if [ ! -e "$TMPDIR/.canardien-$PINGHOST-$HOST" ]; then
+				# set time stamp
+				echo -ne "$TIME_STAMP" > "$TMPDIR/.canardien-$PINGHOST-$HOST"
+				# send alert
+				sendalert
+			elif [ -n "$DEBUG" ]; then
+				shout "Down since `cat $TMPDIR/.canardien-$PINGHOST-$HOST`."
+			fi
+	else
+	  # Host is up
+		if [ -e "$TMPDIR/.canardien-$PINGHOST-$HOST" ]; then
+			if [ -n "$DEBUG" ]; then
+				shout "$HOST is up again."
+			fi
+			# send alert
+			ALERT_SUBJECT='"The host $HOST answers again!"'
+			ALERT_TEXT='"[$(date +"%a %e.%m.%y %H:%M:%S")]\n\n\n$HOST is up again.\n--------------------------------------\n(downtime began $(cat "$TMPDIR/.canardien-$PINGHOST-$HOST"))\n\n\n		Kind regards, $PINGHOST."'
+			sendalert
+			# delete tmp file
+			rm "$TMPDIR/.canardien-$PINGHOST-$HOST"
+		else
+			# still running
+			if [ ! "$DEBUG" = "low" ] && [ -n "$DEBUG"  ]; then
+				shout "$HOST is up."
+			fi
+		fi
+	fi
 }
 
+
 # Send an email alert
-function sendalert {
-   # send mail
+function sendalert() {
+	# send mail
 	if [ ! -z "$ALERT_TO" ]; then
-   		eval MSG=\$$ALERT_TEXT
-   		echo -e -n "$MSG" | mail -s "$ALERT_SUBJECT" "$ALERT_TO"
-   		if [ -n "$DEBUG" ]; then
-    		shout "Alert sent to $ALERT_TO."
-   		fi
+			eval alert_subject=\$$ALERT_SUBJECT
+			eval MSG=\$$ALERT_TEXT
+			echo -e -n "$MSG" | mail -s "$alert_subject" "$ALERT_TO"
+			if [ -n "$DEBUG" ]; then
+				shout "Alert sent to $ALERT_TO."
+			fi
 	fi
 }
 
+
 # To avoid any output in case of a silent operation,
 # shout instead of echo.
-function shout()
-{
-   if [ -z "$SILENT" ]; then
-      echo -e "$1"
-   fi
+function shout() {
+	if [ -z "$SILENT" ]; then
+		echo -e "$1"
+	fi
 }
 
 
 # -----------main-----------
 
-checkconnection
-rememberstate
+init "$*"
+
+# call an instance for each host, when multiple hosts are given
+if [[ "$HOSTS" =~ " " ]]; then
+	while read -r HOST; do
+		"$0" "$HOST" &
+	done <<< "$(echo "$HOSTS" | tr ' ' '\n')"
+	exit 0
+else
+	# process a single host
+	HOST="$HOSTS"
+	checkconnection
+fi
+
 exit 0
 
+# todo: Switches ( -q, --debug, ...)
+#	grace period: do not send a mail if down time shorter than X minutes
+#	repeat down info after x hours
+#	test port instead of ping or in addition