# Licensed to the Apache Software Foundation (ASF) under one
  # or more contributor license agreements.  See the NOTICE file
  # distributed with this work for additional information
  # regarding copyright ownership.  The ASF licenses this file
  # to you under the Apache License, Version 2.0 (the
  # "License"); you may not use this file except in compliance
  # with the License.  You may obtain a copy of the License at
  #
  #     http://www.apache.org/licenses/LICENSE-2.0
  #
  # Unless required by applicable law or agreed to in writing, software
  # distributed under the License is distributed on an "AS IS" BASIS,
  # WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
  # See the License for the specific language governing permissions and
  # limitations under the License.
  
  calculate_heap_sizes()
  {
      case "`uname`" in
          Linux)
              system_memory_in_mb=`free -m | awk '/:/ {print $2;exit}'`
              system_cpu_cores=`egrep -c 'processor([[:space:]]+):.*' /proc/cpuinfo`
          ;;
          FreeBSD)
              system_memory_in_bytes=`sysctl hw.physmem | awk '{print $2}'`
              system_memory_in_mb=`expr $system_memory_in_bytes / 1024 / 1024`
              system_cpu_cores=`sysctl hw.ncpu | awk '{print $2}'`
          ;;
          SunOS)
              system_memory_in_mb=`prtconf | awk '/Memory size:/ {print $3}'`
              system_cpu_cores=`psrinfo | wc -l`
          ;;
          Darwin)
              system_memory_in_bytes=`sysctl hw.memsize | awk '{print $2}'`
              system_memory_in_mb=`expr $system_memory_in_bytes / 1024 / 1024`
              system_cpu_cores=`sysctl hw.ncpu | awk '{print $2}'`
          ;;
          *)
              # assume reasonable defaults for e.g. a modern desktop or
              # cheap server
              system_memory_in_mb="2048"
              system_cpu_cores="2"
          ;;
      esac
  
      # some systems like the raspberry pi don't report cores, use at least 1
      if [ "$system_cpu_cores" -lt "1" ]
      then
          system_cpu_cores="1"
      fi
  
      # set max heap size based on the following
      # max(min(1/2 ram, 1024MB), min(1/4 ram, 8GB))
      # calculate 1/2 ram and cap to 1024MB
      # calculate 1/4 ram and cap to 8192MB
      # pick the max
      half_system_memory_in_mb=`expr $system_memory_in_mb / 2`
      quarter_system_memory_in_mb=`expr $half_system_memory_in_mb / 2`
      if [ "$half_system_memory_in_mb" -gt "1024" ]
      then
          half_system_memory_in_mb="1024"
      fi
      if [ "$quarter_system_memory_in_mb" -gt "8192" ]
      then
          quarter_system_memory_in_mb="8192"
      fi
      if [ "$half_system_memory_in_mb" -gt "$quarter_system_memory_in_mb" ]
      then
          max_heap_size_in_mb="$half_system_memory_in_mb"
      else
          max_heap_size_in_mb="$quarter_system_memory_in_mb"
      fi
      MAX_HEAP_SIZE="${max_heap_size_in_mb}M"
  
      # Young gen: min(max_sensible_per_modern_cpu_core * num_cores, 1/4 * heap size)
      max_sensible_yg_per_core_in_mb="100"
      max_sensible_yg_in_mb=`expr $max_sensible_yg_per_core_in_mb "*" $system_cpu_cores`
  
      desired_yg_in_mb=`expr $max_heap_size_in_mb / 4`
  
      if [ "$desired_yg_in_mb" -gt "$max_sensible_yg_in_mb" ]
      then
          HEAP_NEWSIZE="${max_sensible_yg_in_mb}M"
      else
          HEAP_NEWSIZE="${desired_yg_in_mb}M"
      fi
  }
  
  # Determine the sort of JVM we'll be running on.
  java_ver_output=`"${JAVA:-java}" -version 2>&1`
  jvmver=`echo "$java_ver_output" | grep '[openjdk|java] version' | awk -F'"' 'NR==1 {print $2}' | cut -d\- -f1`
  JVM_VERSION=${jvmver%_*}
  JVM_PATCH_VERSION=${jvmver#*_}
  
  if [ "$JVM_VERSION" \< "1.8" ] ; then
      echo "Cassandra 3.0 and later require Java 8u40 or later."
      exit 1;
  fi
  
  if [ "$JVM_VERSION" \< "1.8" ] && [ "$JVM_PATCH_VERSION" -lt 40 ] ; then
      echo "Cassandra 3.0 and later require Java 8u40 or later."
      exit 1;
  fi
  
  jvm=`echo "$java_ver_output" | grep -A 1 'java version' | awk 'NR==2 {print $1}'`
  case "$jvm" in
      OpenJDK)
          JVM_VENDOR=OpenJDK
          # this will be "64-Bit" or "32-Bit"
          JVM_ARCH=`echo "$java_ver_output" | awk 'NR==3 {print $2}'`
          ;;
      "Java(TM)")
          JVM_VENDOR=Oracle
          # this will be "64-Bit" or "32-Bit"
          JVM_ARCH=`echo "$java_ver_output" | awk 'NR==3 {print $3}'`
          ;;
      *)
          # Help fill in other JVM values
          JVM_VENDOR=other
          JVM_ARCH=unknown
          ;;
  esac
  
  #GC log path has to be defined here because it needs to access CASSANDRA_HOME
  JVM_OPTS="$JVM_OPTS -Xloggc:${CASSANDRA_HOME}/logs/gc.log"
  
  # Here we create the arguments that will get passed to the jvm when
  # starting cassandra.
  
  # Read user-defined JVM options from jvm.options file
  JVM_OPTS_FILE=$CASSANDRA_CONF/jvm.options
  for opt in `grep "^-" $JVM_OPTS_FILE`
  do
    JVM_OPTS="$JVM_OPTS $opt"
  done
  
  # Check what parameters were defined on jvm.options file to avoid conflicts
  echo $JVM_OPTS | grep -q Xmn
  DEFINED_XMN=$?
  echo $JVM_OPTS | grep -q Xmx
  DEFINED_XMX=$?
  echo $JVM_OPTS | grep -q Xms
  DEFINED_XMS=$?
  echo $JVM_OPTS | grep -q UseConcMarkSweepGC
  USING_CMS=$?
  echo $JVM_OPTS | grep -q UseG1GC
  USING_G1=$?
  
  # Override these to set the amount of memory to allocate to the JVM at
  # start-up. For production use you may wish to adjust this for your
  # environment. MAX_HEAP_SIZE is the total amount of memory dedicated
  # to the Java heap. HEAP_NEWSIZE refers to the size of the young
  # generation. Both MAX_HEAP_SIZE and HEAP_NEWSIZE should be either set
  # or not (if you set one, set the other).
  #
  # The main trade-off for the young generation is that the larger it
  # is, the longer GC pause times will be. The shorter it is, the more
  # expensive GC will be (usually).
  #
  # The example HEAP_NEWSIZE assumes a modern 8-core+ machine for decent pause
  # times. If in doubt, and if you do not particularly want to tweak, go with
  # 100 MB per physical CPU core.
  
  #MAX_HEAP_SIZE="6G"
  #HEAP_NEWSIZE="200M"
  
  # Set this to control the amount of arenas per-thread in glibc
  #export MALLOC_ARENA_MAX=4
  
  # only calculate the size if it's not set manually
  if [ "x$MAX_HEAP_SIZE" = "x" ] && [ "x$HEAP_NEWSIZE" = "x" -o $USING_G1 -eq 0 ]; then
      calculate_heap_sizes
  elif [ "x$MAX_HEAP_SIZE" = "x" ] ||  [ "x$HEAP_NEWSIZE" = "x" -a $USING_G1 -ne 0 ]; then
      echo "please set or unset MAX_HEAP_SIZE and HEAP_NEWSIZE in pairs when using CMS GC (see cassandra-env.sh)"
      exit 1
  fi
  
  if [ "x$MALLOC_ARENA_MAX" = "x" ] ; then
      export MALLOC_ARENA_MAX=4
  fi
  
  # We only set -Xms and -Xmx if they were not defined on jvm.options file
  # If defined, both Xmx and Xms should be defined together.
  if [ $DEFINED_XMX -ne 0 ] && [ $DEFINED_XMS -ne 0 ]; then
       JVM_OPTS="$JVM_OPTS -Xms${MAX_HEAP_SIZE}"
       JVM_OPTS="$JVM_OPTS -Xmx${MAX_HEAP_SIZE}"
  elif [ $DEFINED_XMX -ne 0 ] || [ $DEFINED_XMS -ne 0 ]; then
       echo "Please set or unset -Xmx and -Xms flags in pairs on jvm.options file."
       exit 1
  fi
  
  # We only set -Xmn flag if it was not defined in jvm.options file
  # and if the CMS GC is being used
  # If defined, both Xmn and Xmx should be defined together.
  if [ $DEFINED_XMN -eq 0 ] && [ $DEFINED_XMX -ne 0 ]; then
      echo "Please set or unset -Xmx and -Xmn flags in pairs on jvm.options file."
      exit 1
  elif [ $DEFINED_XMN -ne 0 ] && [ $USING_CMS -eq 0 ]; then
      JVM_OPTS="$JVM_OPTS -Xmn${HEAP_NEWSIZE}"
  fi
  
  if [ "$JVM_ARCH" = "64-Bit" ] && [ $USING_CMS -eq 0 ]; then
      JVM_OPTS="$JVM_OPTS -XX:+UseCondCardMark"
  fi
  
  # provides hints to the JIT compiler
  JVM_OPTS="$JVM_OPTS -XX:CompileCommandFile=$CASSANDRA_CONF/hotspot_compiler"
  
  # add the jamm javaagent
  JVM_OPTS="$JVM_OPTS -javaagent:$CASSANDRA_HOME/lib/jamm-0.3.0.jar"
  
  # set jvm HeapDumpPath with CASSANDRA_HEAPDUMP_DIR
  if [ "x$CASSANDRA_HEAPDUMP_DIR" != "x" ]; then
      JVM_OPTS="$JVM_OPTS -XX:HeapDumpPath=$CASSANDRA_HEAPDUMP_DIR/cassandra-`date +%s`-pid$$.hprof"
  fi
  
  # jmx: metrics and administration interface
  #
  # add this if you're having trouble connecting:
  # JVM_OPTS="$JVM_OPTS -Djava.rmi.server.hostname=<public name>"
  #
  # see
  # https://blogs.oracle.com/jmxetc/entry/troubleshooting_connection_problems_in_jconsole
  # for more on configuring JMX through firewalls, etc. (Short version:
  # get it working with no firewall first.)
  #
  # Cassandra ships with JMX accessible *only* from localhost.  
  # To enable remote JMX connections, uncomment lines below
  # with authentication and/or ssl enabled. See https://wiki.apache.org/cassandra/JmxSecurity 
  #
  if [ "x$LOCAL_JMX" = "x" ]; then
      LOCAL_JMX=yes
  fi
  
  # Specifies the default port over which Cassandra will be available for
  # JMX connections.
  # For security reasons, you should not expose this port to the internet.  Firewall it if needed.
  JMX_PORT="7199"
  
  if [ "$LOCAL_JMX" = "yes" ]; then
    JVM_OPTS="$JVM_OPTS -Dcassandra.jmx.local.port=$JMX_PORT"
    JVM_OPTS="$JVM_OPTS -Dcom.sun.management.jmxremote.authenticate=false"
  else
    JVM_OPTS="$JVM_OPTS -Dcassandra.jmx.remote.port=$JMX_PORT"
    # if ssl is enabled the same port cannot be used for both jmx and rmi so either
    # pick another value for this property or comment out to use a random port (though see CASSANDRA-7087 for origins)
    JVM_OPTS="$JVM_OPTS -Dcom.sun.management.jmxremote.rmi.port=$JMX_PORT"
  
    # turn on JMX authentication. See below for further options
    JVM_OPTS="$JVM_OPTS -Dcom.sun.management.jmxremote.authenticate=true"
  
    # jmx ssl options
    #JVM_OPTS="$JVM_OPTS -Dcom.sun.management.jmxremote.ssl=true"
    #JVM_OPTS="$JVM_OPTS -Dcom.sun.management.jmxremote.ssl.need.client.auth=true"
    #JVM_OPTS="$JVM_OPTS -Dcom.sun.management.jmxremote.ssl.enabled.protocols=<enabled-protocols>"
    #JVM_OPTS="$JVM_OPTS -Dcom.sun.management.jmxremote.ssl.enabled.cipher.suites=<enabled-cipher-suites>"
    #JVM_OPTS="$JVM_OPTS -Djavax.net.ssl.keyStore=/path/to/keystore"
    #JVM_OPTS="$JVM_OPTS -Djavax.net.ssl.keyStorePassword=<keystore-password>"
    #JVM_OPTS="$JVM_OPTS -Djavax.net.ssl.trustStore=/path/to/truststore"
    #JVM_OPTS="$JVM_OPTS -Djavax.net.ssl.trustStorePassword=<truststore-password>"
  fi
  
  # jmx authentication and authorization options. By default, auth is only
  # activated for remote connections but they can also be enabled for local only JMX
  ## Basic file based authn & authz
  JVM_OPTS="$JVM_OPTS -Dcom.sun.management.jmxremote.password.file=/etc/cassandra/jmxremote.password"
  #JVM_OPTS="$JVM_OPTS -Dcom.sun.management.jmxremote.access.file=/etc/cassandra/jmxremote.access"
  ## Custom auth settings which can be used as alternatives to JMX's out of the box auth utilities.
  ## JAAS login modules can be used for authentication by uncommenting these two properties.
  ## Cassandra ships with a LoginModule implementation - org.apache.cassandra.auth.CassandraLoginModule -
  ## which delegates to the IAuthenticator configured in cassandra.yaml. See the sample JAAS configuration
  ## file cassandra-jaas.config
  #JVM_OPTS="$JVM_OPTS -Dcassandra.jmx.remote.login.config=CassandraLogin"
  #JVM_OPTS="$JVM_OPTS -Djava.security.auth.login.config=$CASSANDRA_HOME/conf/cassandra-jaas.config"
  
  ## Cassandra also ships with a helper for delegating JMX authz calls to the configured IAuthorizer,
  ## uncomment this to use it. Requires one of the two authentication options to be enabled
  #JVM_OPTS="$JVM_OPTS -Dcassandra.jmx.authorizer=org.apache.cassandra.auth.jmx.AuthorizationProxy"
  
  # To use mx4j, an HTML interface for JMX, add mx4j-tools.jar to the lib/
  # directory.
  # See http://wiki.apache.org/cassandra/Operations#Monitoring_with_MX4J
  # By default mx4j listens on 0.0.0.0:8081. Uncomment the following lines
  # to control its listen address and port.
  #MX4J_ADDRESS="-Dmx4jaddress=127.0.0.1"
  #MX4J_PORT="-Dmx4jport=8081"
  
  # Cassandra uses SIGAR to capture OS metrics CASSANDRA-7838
  # for SIGAR we have to set the java.library.path
  # to the location of the native libraries.
  JVM_OPTS="$JVM_OPTS -Djava.library.path=$CASSANDRA_HOME/lib/sigar-bin"
  
  JVM_OPTS="$JVM_OPTS $MX4J_ADDRESS"
  JVM_OPTS="$JVM_OPTS $MX4J_PORT"
  JVM_OPTS="$JVM_OPTS $JVM_EXTRA_OPTS"