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chapter10/proc_watch.ksh

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+#!/bin/ksh
+#
+# SCRIPT: proc_watch.ksh
+# AUTHOR: Randy Michael
+# DATE: 09-12-2007
+# REV: 1.0.P
+# PLATFORM: Not Platform Dependent
+#
+# PURPOSE: This script is used to monitor and log
+# the status of a process as it starts and stops.
+#
+# REV LIST:
+#
+# set -x # Uncomment to debug this script
+# set -n # Uncomment to check syntax without ANY execution
+#
+####################################################
+########## DEFINE FILES AND VARIABLES HERE #########
+####################################################
+
+LOGFILE="/tmp/proc_status.log"
+[[ ! -s $LOGFILE ]] && touch $LOGFILE
+
+PROCESS="$1" # Process to Monitor
+SCRIPT_NAME=$(basename $0) # Script Name w/o the PATH
+TTY=$(tty) # Current tty or pty
+
+####################################################
+############# DEFINE FUNCTIONS HERE ################
+####################################################
+
+usage ()
+{
+    echo "\nUSAGE: $SCRIPT_NAME process_to_monitor\n"
+}
+
+####################################################
+
+trap_exit ()
+{
+    # Log an ending time for process monitoring
+    TIMESTAMP=$(date +%D@%T) # Get a new timestamp...
+    echo "MON_STOP: Monitoring for $PROCESS ended ==> $TIMESTAMP" \
+         | tee -a $LOGFILE
+
+    # Kill all functions
+    kill -9 $(jobs -p) 2>/dev/null
+}
+
+####################################################
+
+mon_proc_end ()
+{
+    END_RC="0"
+    until (( END_RC != 0 ))
+    do
+       ps aux | grep -v "grep $PROCESS" | grep -v $SCRIPT_NAME \
+              | grep $PROCESS >/dev/null 2>&1
+
+       END_RC=$? # Check the Return Code!!
+       sleep 1 # Needed to reduce CPU load!
+    done
+
+    echo 'N' # Turn the RUN flag off
+
+    # Grab a Timestamp
+    TIMESTAMP=$(date +%D@%T)
+
+    echo "END PROCESS: $PROCESS ended ==> $TIMESTAMP" >> $LOGFILE &
+    echo "END PROCESS: $PROCESS ended ==> $TIMESTAMP" > $TTY
+}
+####################################################
+
+mon_proc_start ()
+{
+    START_RC="-1" # Initialize to -1
+    until (( START_RC == 0 ))
+    do
+        ps aux | grep -v "grep $PROCESS" | grep -v $SCRIPT_NAME \
+               | grep $PROCESS >/dev/null 2>&1
+
+        START_RC=$? # Check the Return Code!!!
+        sleep 1 # Needed to reduce CPU load!
+    done
+
+    echo 'Y' # Turn the RUN flag on
+
+    # Grab the timestamp
+    TIMESTAMP=$(date +%D@%T)
+
+    echo "START PROCESS: $PROCESS began ==> $TIMESTAMP" >> $LOGFILE &
+    echo "START PROCESS: $PROCESS began ==> $TIMESTAMP" > $TTY
+}
+
+####################################################
+############## START OF MAIN #######################
+####################################################
+
+### SET A TRAP ####
+
+trap 'trap_exit; exit 0' 1 2 3 15
+
+# Check for the Correct Command Line Argument - Only 1
+
+if (( $# != 1 ))
+then
+     usage
+     exit 1
+fi
+
+# Get an Initial Process State and Set the RUN Flag
+
+ps aux | grep -v "grep $PROCESS" | grep -v $SCRIPT_NAME \
+       | grep $PROCESS >/dev/null
+
+PROC_RC=$? # Check the Return Code!!
+
+# Give some initial feedback before starting the loop
+
+if (( PROC_RC == 0 ))
+then
+     echo "The $PROCESS process is currently running...Monitoring..."
+     RUN="Y" # Set the RUN Flag to YES
+else
+     echo "The $PROCESS process is not currently running...Monitoring..."
+     RUN="N" # Set the RUN Flag to NO
+fi
+
+TIMESTAMP=$(date +%D@%T) # Grab a timestamp for the log
+
+# Use a "tee -a $#LOGFILE" to send output to both standard output
+# and to the file referenced by $LOGFILE
+
+echo "MON_START: Monitoring for $PROCESS began ==> $TIMESTAMP" \
+      | tee -a $LOGFILE
+
+# Loop Forever!!
+
+while :
+do
+     case $RUN in
+     'Y') # Loop Until the Process Ends
+          RUN=$(mon_proc_end)
+          ;;
+     'N') # Loop Until the Process Starts
+          RUN=$(mon_proc_start)
+          ;;
+     esac
+done
+
+# End of Script