Apache Tomcat Shell 启动文件分析

川长思鸟来 2023-05-22 08:47 26阅读 0赞

当我们进行 web 企业开发完成的时候，正式项目都是在 Linux 上进行发布。首先会把开发好的项目打包成 xxx.war 文件，然后把这个 war 包放在 tomcat 中的 webapps 目录中。最后通过 `${TOMCAT_HOME}/bin/startup.sh` 文件启动项目，接着就可以在浏览器中访问开发好的项目了。下面我们就来简单分析一下 `startup.sh` 文件。

> startup.sh

os400=false
    case "`uname`" in
    OS400*) os400=true;;
    esac
    
    # resolve links - $0 may be a softlink
    PRG="$0"
    
    while [ -h "$PRG" ] ; do
      ls=`ls -ld "$PRG"`
      link=`expr "$ls" : '.*-> $.*$$'`
      if expr "$link" : '/.*' > /dev/null; then
        PRG="$link"
      else
        PRG=`dirname "$PRG"`/"$link"
      fi
    done
    
    PRGDIR=`dirname "$PRG"`
    EXECUTABLE=catalina.sh
    
    # Check that target executable exists
    if $os400; then
      # -x will Only work on the os400 if the files are:
      # 1. owned by the user
      # 2. owned by the PRIMARY group of the user
      # this will not work if the user belongs in secondary groups
      eval
    else
      if [ ! -x "$PRGDIR"/"$EXECUTABLE" ]; then
        echo "Cannot find $PRGDIR/$EXECUTABLE"
        echo "The file is absent or does not have execute permission"
        echo "This file is needed to run this program"
        exit 1
      fi
    fi
    
    exec "$PRGDIR"/"$EXECUTABLE" start "$@"

上面都都不重要，最重要的就是最后一句：

exec "$PRGDIR"/"$EXECUTABLE" start "$@"

`exec` 在 shell 命令中是执行的意思， 而 `$EXECUTABLE` 就是前面的 `catalina.sh` 变量。执行 `startup.sh` shell 文件，它会调用 `catalina.sh` 文件。下面我们就来分析一下 `catalina.sh` 文件:

#!/bin/sh
    
    # 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.
    
    # -----------------------------------------------------------------------------
    # Control Script for the CATALINA Server
    #
    # For supported commands call "catalina.sh help" or see the usage section at
    # the end of this file.
    #
    # Environment Variable Prerequisites
    #
    # Do not set the variables in this script. Instead put them into a script
    # setenv.sh in CATALINA_BASE/bin to keep your customizations separate.
    #
    # CATALINA_HOME May point at your Catalina "build" directory.
    #
    # CATALINA_BASE (Optional) Base directory for resolving dynamic portions
    # of a Catalina installation. If not present, resolves to
    # the same directory that CATALINA_HOME points to.
    #
    # CATALINA_OUT (Optional) Full path to a file where stdout and stderr
    # will be redirected.
    # Default is $CATALINA_BASE/logs/catalina.out
    #
    # CATALINA_OPTS (Optional) Java runtime options used when the "start",
    # "run" or "debug" command is executed.
    # Include here and not in JAVA_OPTS all options, that should
    # only be used by Tomcat itself, not by the stop process,
    # the version command etc.
    # Examples are heap size, GC logging, JMX ports etc.
    #
    # CATALINA_TMPDIR (Optional) Directory path location of temporary directory
    # the JVM should use (java.io.tmpdir). Defaults to
    # $CATALINA_BASE/temp.
    #
    # JAVA_HOME Must point at your Java Development Kit installation.
    # Required to run the with the "debug" argument.
    #
    # JRE_HOME Must point at your Java Runtime installation.
    # Defaults to JAVA_HOME if empty. If JRE_HOME and JAVA_HOME
    # are both set, JRE_HOME is used.
    #
    # JAVA_OPTS (Optional) Java runtime options used when any command
    # is executed.
    # Include here and not in CATALINA_OPTS all options, that
    # should be used by Tomcat and also by the stop process,
    # the version command etc.
    # Most options should go into CATALINA_OPTS.
    #
    # JAVA_ENDORSED_DIRS (Optional) Lists of of colon separated directories
    # containing some jars in order to allow replacement of APIs
    # created outside of the JCP (i.e. DOM and SAX from W3C).
    # It can also be used to update the XML parser implementation.
    # This is only supported for Java <= 8.
    # Defaults to $CATALINA_HOME/endorsed.
    #
    # JPDA_TRANSPORT (Optional) JPDA transport used when the "jpda start"
    # command is executed. The default is "dt_socket".
    #
    # JPDA_ADDRESS (Optional) Java runtime options used when the "jpda start"
    # command is executed. The default is localhost:8000.
    #
    # JPDA_SUSPEND (Optional) Java runtime options used when the "jpda start"
    # command is executed. Specifies whether JVM should suspend
    # execution immediately after startup. Default is "n".
    #
    # JPDA_OPTS (Optional) Java runtime options used when the "jpda start"
    # command is executed. If used, JPDA_TRANSPORT, JPDA_ADDRESS,
    # and JPDA_SUSPEND are ignored. Thus, all required jpda
    # options MUST be specified. The default is:
    #
    # -agentlib:jdwp=transport=$JPDA_TRANSPORT,
    # address=$JPDA_ADDRESS,server=y,suspend=$JPDA_SUSPEND
    #
    # JSSE_OPTS (Optional) Java runtime options used to control the TLS
    # implementation when JSSE is used. Default is:
    # "-Djdk.tls.ephemeralDHKeySize=2048"
    #
    # CATALINA_PID (Optional) Path of the file which should contains the pid
    # of the catalina startup java process, when start (fork) is
    # used
    #
    # CATALINA_LOGGING_CONFIG (Optional) Override Tomcat's logging config file
    # Example (all one line)
    # CATALINA_LOGGING_CONFIG="-Djava.util.logging.config.file=$CATALINA_BASE/conf/logging.properties"
    #
    # LOGGING_CONFIG Deprecated
    # Use CATALINA_LOGGING_CONFIG
    # This is only used if CATALINA_LOGGING_CONFIG is not set
    # and LOGGING_CONFIG starts with "-D..."
    #
    # LOGGING_MANAGER (Optional) Override Tomcat's logging manager
    # Example (all one line)
    # LOGGING_MANAGER="-Djava.util.logging.manager=org.apache.juli.ClassLoaderLogManager"
    #
    # UMASK (Optional) Override Tomcat's default UMASK of 0027
    #
    # USE_NOHUP (Optional) If set to the string true the start command will
    # use nohup so that the Tomcat process will ignore any hangup
    # signals. Default is "false" unless running on HP-UX in which
    # case the default is "true"
    # -----------------------------------------------------------------------------
    
    # OS specific support. $var _must_ be set to either true or false.
    ### 1 系统判定 ###
    #
    # 此处语句判断操作系统，同时对操作系统支持
    # Cygwin 是 windows平台上运行的类UNIX模拟环境
    # Darwin 是 MacOSX 操作环境的操作系统成份
    # OS400 是 IBM的AIX
    # HP-UX 是 惠普公司的UNIX系统
    cygwin=false
    darwin=false
    os400=false
    hpux=false
    case "`uname`" in
    CYGWIN*) cygwin=true;;
    Darwin*) darwin=true;;
    OS400*) os400=true;;
    HP-UX*) hpux=true;;
    esac
    
    # resolve links - $0 may be a softlink
    ### 2 连接符判定 ###
    ### 此处的RPG抓取的是文件名，因为可能是符号链接，所以下面循环语句的作用就是找到文件真实源路径 ###
    PRG="$0"
    
    while [ -h "$PRG" ]; do
      ls=`ls -ld "$PRG"`
      link=`expr "$ls" : '.*-> $.*$$'`
      if expr "$link" : '/.*' > /dev/null; then
        PRG="$link"
      else
        PRG=`dirname "$PRG"`/"$link"
      fi
    done
    
    # Get standard environment variables
    
    ### 3 脚本目录真实目录地址 ###
    ### 获取脚本目录真实目录地址 ###
    
    PRGDIR=`dirname "$PRG"`
    
    # Only set CATALINA_HOME if not already set
    [ -z "$CATALINA_HOME" ] && CATALINA_HOME=`cd "$PRGDIR/.." >/dev/null; pwd`
    
    # Copy CATALINA_BASE from CATALINA_HOME if not already set
    [ -z "$CATALINA_BASE" ] && CATALINA_BASE="$CATALINA_HOME"
    
    #上面两个语句判断变量$CATALINA_HOME和$CATALINA_BASE是否存在，不存在则给予附值
    
    # Ensure that any user defined CLASSPATH variables are not used on startup,
    # but allow them to be specified in setenv.sh, in rare case when it is needed.
    CLASSPATH=
    
    ### 4 查看文件是否可读 ###
    
    if [ -r "$CATALINA_BASE/bin/setenv.sh" ]; then
      . "$CATALINA_BASE/bin/setenv.sh"
    elif [ -r "$CATALINA_HOME/bin/setenv.sh" ]; then
      . "$CATALINA_HOME/bin/setenv.sh"
    fi
    #默认的tomcat的bin目录下没有这个文件，可以自行编写setenv.sh这个文件设定环境变量
    # For Cygwin, ensure paths are in UNIX format before anything is touched
    if $cygwin; then
      [ -n "$JAVA_HOME" ] && JAVA_HOME=`cygpath --unix "$JAVA_HOME"`
      [ -n "$JRE_HOME" ] && JRE_HOME=`cygpath --unix "$JRE_HOME"`
      [ -n "$CATALINA_HOME" ] && CATALINA_HOME=`cygpath --unix "$CATALINA_HOME"`
      [ -n "$CATALINA_BASE" ] && CATALINA_BASE=`cygpath --unix "$CATALINA_BASE"`
      [ -n "$CLASSPATH" ] && CLASSPATH=`cygpath --path --unix "$CLASSPATH"`
    fi
    
    # Ensure that neither CATALINA_HOME nor CATALINA_BASE contains a colon
    # as this is used as the separator in the classpath and Java provides no
    # mechanism for escaping if the same character appears in the path.
    case $CATALINA_HOME in
      *:*) echo "Using CATALINA_HOME: $CATALINA_HOME";
           echo "Unable to start as CATALINA_HOME contains a colon (:) character";
           exit 1;
    esac
    case $CATALINA_BASE in
      *:*) echo "Using CATALINA_BASE: $CATALINA_BASE";
           echo "Unable to start as CATALINA_BASE contains a colon (:) character";
           exit 1;
    esac
    
    ### 5 系统判断 ###
    #### 0S400 ###
    
    # For OS400
    if $os400; then
      # Set job priority to standard for interactive (interactive - 6) by using
      # the interactive priority - 6, the helper threads that respond to requests
      # will be running at the same priority as interactive jobs.
      COMMAND='chgjob job('$JOBNAME') runpty(6)'
      system $COMMAND
    
      # Enable multi threading
      export QIBM_MULTI_THREADED=Y
    fi
    
    # Get standard Java environment variables
    if $os400; then
      # -r will Only work on the os400 if the files are:
      # 1. owned by the user
      # 2. owned by the PRIMARY group of the user
      # this will not work if the user belongs in secondary groups
      . "$CATALINA_HOME"/bin/setclasspath.sh
    else
      if [ -r "$CATALINA_HOME"/bin/setclasspath.sh ]; then
        . "$CATALINA_HOME"/bin/setclasspath.sh
      else
        echo "Cannot find $CATALINA_HOME/bin/setclasspath.sh"
        echo "This file is needed to run this program"
        exit 1
      fi
    fi
    
    # Add on extra jar files to CLASSPATH
    if [ ! -z "$CLASSPATH" ] ; then
      CLASSPATH="$CLASSPATH":
    fi
    CLASSPATH="$CLASSPATH""$CATALINA_HOME"/bin/bootstrap.jar
    
    if [ -z "$CATALINA_OUT" ] ; then
      CATALINA_OUT="$CATALINA_BASE"/logs/catalina.out
    fi
    
    if [ -z "$CATALINA_TMPDIR" ] ; then
      # Define the java.io.tmpdir to use for Catalina
      CATALINA_TMPDIR="$CATALINA_BASE"/temp
    fi
    
    # Add tomcat-juli.jar to classpath
    # tomcat-juli.jar can be over-ridden per instance
    if [ -r "$CATALINA_BASE/bin/tomcat-juli.jar" ] ; then
      CLASSPATH=$CLASSPATH:$CATALINA_BASE/bin/tomcat-juli.jar
    else
      CLASSPATH=$CLASSPATH:$CATALINA_HOME/bin/tomcat-juli.jar
    fi
    
    # Bugzilla 37848: When no TTY is available, don't output to console
    have_tty=0
    if [ -t 0 ]; then
        have_tty=1
    fi
    
    ### Cygwin 系统 ###
    
    # For Cygwin, switch paths to Windows format before running java
    if $cygwin; then
      JAVA_HOME=`cygpath --absolute --windows "$JAVA_HOME"`
      JRE_HOME=`cygpath --absolute --windows "$JRE_HOME"`
      CATALINA_HOME=`cygpath --absolute --windows "$CATALINA_HOME"`
      CATALINA_BASE=`cygpath --absolute --windows "$CATALINA_BASE"`
      CATALINA_TMPDIR=`cygpath --absolute --windows "$CATALINA_TMPDIR"`
      CLASSPATH=`cygpath --path --windows "$CLASSPATH"`
      [ -n "$JAVA_ENDORSED_DIRS" ] && JAVA_ENDORSED_DIRS=`cygpath --path --windows "$JAVA_ENDORSED_DIRS"`
    fi
    
    if [ -z "$JSSE_OPTS" ] ; then
      JSSE_OPTS="-Djdk.tls.ephemeralDHKeySize=2048"
    fi
    JAVA_OPTS="$JAVA_OPTS $JSSE_OPTS"
    
    # Register custom URL handlers
    # Do this here so custom URL handles (specifically 'war:...') can be used in the security policy
    JAVA_OPTS="$JAVA_OPTS -Djava.protocol.handler.pkgs=org.apache.catalina.webresources"
    
    # Check for the deprecated LOGGING_CONFIG
    # Only use it if CATALINA_LOGGING_CONFIG is not set and LOGGING_CONFIG starts with "-D..."
    if [ -z "$CATALINA_LOGGING_CONFIG" ]; then
      if [ "${LOGGING_CONFIG#*-D}" != "$LOGGING_CONFIG" ]; then
        CATALINA_LOGGING_CONFIG="$LOGGING_CONFIG"
      fi
    fi
    
    # Set juli LogManager config file if it is present and an override has not been issued
    if [ -z "$CATALINA_LOGGING_CONFIG" ]; then
      if [ -r "$CATALINA_BASE"/conf/logging.properties ]; then
        CATALINA_LOGGING_CONFIG="-Djava.util.logging.config.file=$CATALINA_BASE/conf/logging.properties"
      else
        # Bugzilla 45585
        CATALINA_LOGGING_CONFIG="-Dnop"
      fi
    fi
    
    if [ -z "$LOGGING_MANAGER" ]; then
      LOGGING_MANAGER="-Djava.util.logging.manager=org.apache.juli.ClassLoaderLogManager"
    fi
    
    # Set UMASK unless it has been overridden
    if [ -z "$UMASK" ]; then
        UMASK="0027"
    fi
    umask $UMASK
    
    # Java 9 no longer supports the java.endorsed.dirs
    # system property. Only try to use it if
    # JAVA_ENDORSED_DIRS was explicitly set
    # or CATALINA_HOME/endorsed exists.
    ENDORSED_PROP=ignore.endorsed.dirs
    if [ -n "$JAVA_ENDORSED_DIRS" ]; then
        ENDORSED_PROP=java.endorsed.dirs
    fi
    if [ -d "$CATALINA_HOME/endorsed" ]; then
        ENDORSED_PROP=java.endorsed.dirs
    fi
    
    # Make the umask available when using the org.apache.catalina.security.SecurityListener
    JAVA_OPTS="$JAVA_OPTS -Dorg.apache.catalina.security.SecurityListener.UMASK=`umask`"
    
    if [ -z "$USE_NOHUP" ]; then
        if $hpux; then
            USE_NOHUP="true"
        else
            USE_NOHUP="false"
        fi
    fi
    unset _NOHUP
    if [ "$USE_NOHUP" = "true" ]; then
        _NOHUP="nohup"
    fi
    
    # Add the JAVA 9 specific start-up parameters required by Tomcat
    JDK_JAVA_OPTIONS="$JDK_JAVA_OPTIONS --add-opens=java.base/java.lang=ALL-UNNAMED"
    JDK_JAVA_OPTIONS="$JDK_JAVA_OPTIONS --add-opens=java.base/java.io=ALL-UNNAMED"
    JDK_JAVA_OPTIONS="$JDK_JAVA_OPTIONS --add-opens=java.rmi/sun.rmi.transport=ALL-UNNAMED"
    export JDK_JAVA_OPTIONS
    
    # ----- Execute The Requested Command -----------------------------------------
    
    # Bugzilla 37848: only output this if we have a TTY
    if [ $have_tty -eq 1 ]; then
      echo "Using CATALINA_BASE: $CATALINA_BASE"
      echo "Using CATALINA_HOME: $CATALINA_HOME"
      echo "Using CATALINA_TMPDIR: $CATALINA_TMPDIR"
      if [ "$1" = "debug" ] ; then
        echo "Using JAVA_HOME: $JAVA_HOME"
      else
        echo "Using JRE_HOME: $JRE_HOME"
      fi
      echo "Using CLASSPATH: $CLASSPATH"
      if [ ! -z "$CATALINA_PID" ]; then
        echo "Using CATALINA_PID: $CATALINA_PID"
      fi
    fi
    
    if [ "$1" = "jpda" ] ; then
      if [ -z "$JPDA_TRANSPORT" ]; then
        JPDA_TRANSPORT="dt_socket"
      fi
      if [ -z "$JPDA_ADDRESS" ]; then
        JPDA_ADDRESS="localhost:8000"
      fi
      if [ -z "$JPDA_SUSPEND" ]; then
        JPDA_SUSPEND="n"
      fi
      if [ -z "$JPDA_OPTS" ]; then
        JPDA_OPTS="-agentlib:jdwp=transport=$JPDA_TRANSPORT,address=$JPDA_ADDRESS,server=y,suspend=$JPDA_SUSPEND"
      fi
      CATALINA_OPTS="$JPDA_OPTS $CATALINA_OPTS"
      shift
    fi
    
    # TODO: Bugzilla 63815
    # This doesn't currently work (and can't be made to work) if values used in
    # CATALINA_OPTS and/or JAVA_OPTS require quoting. See:
    # https://bugs.openjdk.java.net/browse/JDK-8234808
    
    ### 6 根据不同的命令调 ###
    ### Debug 命令 ###
    
    if [ "$1" = "debug" ] ; then
      if $os400; then
        echo "Debug command not available on OS400"
        exit 1
      else
        shift
        if [ "$1" = "-security" ] ; then
          if [ $have_tty -eq 1 ]; then
            echo "Using Security Manager"
          fi
          shift
          exec "$_RUNJDB" "$CATALINA_LOGGING_CONFIG" $LOGGING_MANAGER $JAVA_OPTS $CATALINA_OPTS \
            -D$ENDORSED_PROP="$JAVA_ENDORSED_DIRS" \
            -classpath "$CLASSPATH" \
            -sourcepath "$CATALINA_HOME"/../../java \
            -Djava.security.manager \
            -Djava.security.policy=="$CATALINA_BASE"/conf/catalina.policy \
            -Dcatalina.base="$CATALINA_BASE" \
            -Dcatalina.home="$CATALINA_HOME" \
            -Djava.io.tmpdir="$CATALINA_TMPDIR" \
            org.apache.catalina.startup.Bootstrap "$@" start
        else
          exec "$_RUNJDB" "$CATALINA_LOGGING_CONFIG" $LOGGING_MANAGER $JAVA_OPTS $CATALINA_OPTS \
            -D$ENDORSED_PROP="$JAVA_ENDORSED_DIRS" \
            -classpath "$CLASSPATH" \
            -sourcepath "$CATALINA_HOME"/../../java \
            -Dcatalina.base="$CATALINA_BASE" \
            -Dcatalina.home="$CATALINA_HOME" \
            -Djava.io.tmpdir="$CATALINA_TMPDIR" \
            org.apache.catalina.startup.Bootstrap "$@" start
        fi
      fi
    ### run 命令 ###
    elif [ "$1" = "run" ]; then
    
      shift
      if [ "$1" = "-security" ] ; then
        if [ $have_tty -eq 1 ]; then
          echo "Using Security Manager"
        fi
        shift
        eval exec "\"$_RUNJAVA\"" "\"$CATALINA_LOGGING_CONFIG\"" $LOGGING_MANAGER "$JAVA_OPTS" "$CATALINA_OPTS" \
          -D$ENDORSED_PROP="\"$JAVA_ENDORSED_DIRS\"" \
          -classpath "\"$CLASSPATH\"" \
          -Djava.security.manager \
          -Djava.security.policy=="\"$CATALINA_BASE/conf/catalina.policy\"" \
          -Dcatalina.base="\"$CATALINA_BASE\"" \
          -Dcatalina.home="\"$CATALINA_HOME\"" \
          -Djava.io.tmpdir="\"$CATALINA_TMPDIR\"" \
          org.apache.catalina.startup.Bootstrap "$@" start
      else
        eval exec "\"$_RUNJAVA\"" "\"$CATALINA_LOGGING_CONFIG\"" $LOGGING_MANAGER "$JAVA_OPTS" "$CATALINA_OPTS" \
          -D$ENDORSED_PROP="\"$JAVA_ENDORSED_DIRS\"" \
          -classpath "\"$CLASSPATH\"" \
          -Dcatalina.base="\"$CATALINA_BASE\"" \
          -Dcatalina.home="\"$CATALINA_HOME\"" \
          -Djava.io.tmpdir="\"$CATALINA_TMPDIR\"" \
          org.apache.catalina.startup.Bootstrap "$@" start
      fi
    
    ### start 命令 ###
    
    elif [ "$1" = "start" ] ; then
    
      if [ ! -z "$CATALINA_PID" ]; then
        if [ -f "$CATALINA_PID" ]; then
          if [ -s "$CATALINA_PID" ]; then
            echo "Existing PID file found during start."
            if [ -r "$CATALINA_PID" ]; then
              PID=`cat "$CATALINA_PID"`
              ps -p $PID >/dev/null 2>&1
              if [ $? -eq 0 ] ; then
                echo "Tomcat appears to still be running with PID $PID. Start aborted."
                echo "If the following process is not a Tomcat process, remove the PID file and try again:"
                ps -f -p $PID
                exit 1
              else
                echo "Removing/clearing stale PID file."
                rm -f "$CATALINA_PID" >/dev/null 2>&1
                if [ $? != 0 ]; then
                  if [ -w "$CATALINA_PID" ]; then
                    cat /dev/null > "$CATALINA_PID"
                  else
                    echo "Unable to remove or clear stale PID file. Start aborted."
                    exit 1
                  fi
                fi
              fi
            else
              echo "Unable to read PID file. Start aborted."
              exit 1
            fi
          else
            rm -f "$CATALINA_PID" >/dev/null 2>&1
            if [ $? != 0 ]; then
              if [ ! -w "$CATALINA_PID" ]; then
                echo "Unable to remove or write to empty PID file. Start aborted."
                exit 1
              fi
            fi
          fi
        fi
      fi
    
      shift
      touch "$CATALINA_OUT"
      if [ "$1" = "-security" ] ; then
        if [ $have_tty -eq 1 ]; then
          echo "Using Security Manager"
        fi
        shift
        eval $_NOHUP "\"$_RUNJAVA\"" "\"$CATALINA_LOGGING_CONFIG\"" $LOGGING_MANAGER "$JAVA_OPTS" "$CATALINA_OPTS" \
          -D$ENDORSED_PROP="\"$JAVA_ENDORSED_DIRS\"" \
          -classpath "\"$CLASSPATH\"" \
          -Djava.security.manager \
          -Djava.security.policy=="\"$CATALINA_BASE/conf/catalina.policy\"" \
          -Dcatalina.base="\"$CATALINA_BASE\"" \
          -Dcatalina.home="\"$CATALINA_HOME\"" \
          -Djava.io.tmpdir="\"$CATALINA_TMPDIR\"" \
          org.apache.catalina.startup.Bootstrap "$@" start \
          >> "$CATALINA_OUT" 2>&1 "&"
    
      else
        eval $_NOHUP "\"$_RUNJAVA\"" "\"$CATALINA_LOGGING_CONFIG\"" $LOGGING_MANAGER "$JAVA_OPTS" "$CATALINA_OPTS" \
          -D$ENDORSED_PROP="\"$JAVA_ENDORSED_DIRS\"" \
          -classpath "\"$CLASSPATH\"" \
          -Dcatalina.base="\"$CATALINA_BASE\"" \
          -Dcatalina.home="\"$CATALINA_HOME\"" \
          -Djava.io.tmpdir="\"$CATALINA_TMPDIR\"" \
          org.apache.catalina.startup.Bootstrap "$@" start \
          >> "$CATALINA_OUT" 2>&1 "&"
    
      fi
    
      if [ ! -z "$CATALINA_PID" ]; then
        echo $! > "$CATALINA_PID"
      fi
    
      echo "Tomcat started."
      
    ### stop ###
    
    elif [ "$1" = "stop" ] ; then
    
      shift
    
      SLEEP=5
      if [ ! -z "$1" ]; then
        echo $1 | grep "[^0-9]" >/dev/null 2>&1
        if [ $? -gt 0 ]; then
          SLEEP=$1
          shift
        fi
      fi
    
      FORCE=0
      if [ "$1" = "-force" ]; then
        shift
        FORCE=1
      fi
    
      if [ ! -z "$CATALINA_PID" ]; then
        if [ -f "$CATALINA_PID" ]; then
          if [ -s "$CATALINA_PID" ]; then
            kill -0 `cat "$CATALINA_PID"` >/dev/null 2>&1
            if [ $? -gt 0 ]; then
              echo "PID file found but either no matching process was found or the current user does not have permission to stop the process. Stop aborted."
              exit 1
            fi
          else
            echo "PID file is empty and has been ignored."
          fi
        else
          echo "\$CATALINA_PID was set but the specified file does not exist. Is Tomcat running? Stop aborted."
          exit 1
        fi
      fi
    
      eval "\"$_RUNJAVA\"" $LOGGING_MANAGER "$JAVA_OPTS" \
        -D$ENDORSED_PROP="\"$JAVA_ENDORSED_DIRS\"" \
        -classpath "\"$CLASSPATH\"" \
        -Dcatalina.base="\"$CATALINA_BASE\"" \
        -Dcatalina.home="\"$CATALINA_HOME\"" \
        -Djava.io.tmpdir="\"$CATALINA_TMPDIR\"" \
        org.apache.catalina.startup.Bootstrap "$@" stop
    
      # stop failed. Shutdown port disabled? Try a normal kill.
      if [ $? != 0 ]; then
        if [ ! -z "$CATALINA_PID" ]; then
          echo "The stop command failed. Attempting to signal the process to stop through OS signal."
          kill -15 `cat "$CATALINA_PID"` >/dev/null 2>&1
        fi
      fi
    
      if [ ! -z "$CATALINA_PID" ]; then
        if [ -f "$CATALINA_PID" ]; then
          while [ $SLEEP -ge 0 ]; do
            kill -0 `cat "$CATALINA_PID"` >/dev/null 2>&1
            if [ $? -gt 0 ]; then
              rm -f "$CATALINA_PID" >/dev/null 2>&1
              if [ $? != 0 ]; then
                if [ -w "$CATALINA_PID" ]; then
                  cat /dev/null > "$CATALINA_PID"
                  # If Tomcat has stopped don't try and force a stop with an empty PID file
                  FORCE=0
                else
                  echo "The PID file could not be removed or cleared."
                fi
              fi
              echo "Tomcat stopped."
              break
            fi
            if [ $SLEEP -gt 0 ]; then
              sleep 1
            fi
            if [ $SLEEP -eq 0 ]; then
              echo "Tomcat did not stop in time."
              if [ $FORCE -eq 0 ]; then
                echo "PID file was not removed."
              fi
              echo "To aid diagnostics a thread dump has been written to standard out."
              kill -3 `cat "$CATALINA_PID"`
            fi
            SLEEP=`expr $SLEEP - 1 `
          done
        fi
      fi
    
      KILL_SLEEP_INTERVAL=5
      if [ $FORCE -eq 1 ]; then
        if [ -z "$CATALINA_PID" ]; then
          echo "Kill failed: \$CATALINA_PID not set"
        else
          if [ -f "$CATALINA_PID" ]; then
            PID=`cat "$CATALINA_PID"`
            echo "Killing Tomcat with the PID: $PID"
            kill -9 $PID
            while [ $KILL_SLEEP_INTERVAL -ge 0 ]; do
                kill -0 `cat "$CATALINA_PID"` >/dev/null 2>&1
                if [ $? -gt 0 ]; then
                    rm -f "$CATALINA_PID" >/dev/null 2>&1
                    if [ $? != 0 ]; then
                        if [ -w "$CATALINA_PID" ]; then
                            cat /dev/null > "$CATALINA_PID"
                        else
                            echo "The PID file could not be removed."
                        fi
                    fi
                    echo "The Tomcat process has been killed."
                    break
                fi
                if [ $KILL_SLEEP_INTERVAL -gt 0 ]; then
                    sleep 1
                fi
                KILL_SLEEP_INTERVAL=`expr $KILL_SLEEP_INTERVAL - 1 `
            done
            if [ $KILL_SLEEP_INTERVAL -lt 0 ]; then
                echo "Tomcat has not been killed completely yet. The process might be waiting on some system call or might be UNINTERRUPTIBLE."
            fi
          fi
        fi
      fi
      
    ### configtest ###
    
    elif [ "$1" = "configtest" ] ; then
    
        eval "\"$_RUNJAVA\"" $LOGGING_MANAGER "$JAVA_OPTS" \
          -D$ENDORSED_PROP="\"$JAVA_ENDORSED_DIRS\"" \
          -classpath "\"$CLASSPATH\"" \
          -Dcatalina.base="\"$CATALINA_BASE\"" \
          -Dcatalina.home="\"$CATALINA_HOME\"" \
          -Djava.io.tmpdir="\"$CATALINA_TMPDIR\"" \
          org.apache.catalina.startup.Bootstrap configtest
        result=$?
        if [ $result -ne 0 ]; then
            echo "Configuration error detected!"
        fi
        exit $result
    ### version ###
    elif [ "$1" = "version" ] ; then
    
        "$_RUNJAVA"   \
          -classpath "$CATALINA_HOME/lib/catalina.jar" \
          org.apache.catalina.util.ServerInfo
    
    else
    
      echo "Usage: catalina.sh ( commands ... )"
      echo "commands:"
      if $os400; then
        echo " debug Start Catalina in a debugger (not available on OS400)"
        echo " debug -security Debug Catalina with a security manager (not available on OS400)"
      else
        echo " debug Start Catalina in a debugger"
        echo " debug -security Debug Catalina with a security manager"
      fi
      echo " jpda start Start Catalina under JPDA debugger"
      echo " run Start Catalina in the current window"
      echo " run -security Start in the current window with security manager"
      echo " start Start Catalina in a separate window"
      echo " start -security Start in a separate window with security manager"
      echo " stop Stop Catalina, waiting up to 5 seconds for the process to end"
      echo " stop n Stop Catalina, waiting up to n seconds for the process to end"
      echo " stop -force Stop Catalina, wait up to 5 seconds and then use kill -KILL if still running"
      echo " stop n -force Stop Catalina, wait up to n seconds and then use kill -KILL if still running"
      echo " configtest Run a basic syntax check on server.xml - check exit code for result"
      echo " version What version of tomcat are you running?"
      echo "Note: Waiting for the process to end and use of the -force option require that \$CATALINA_PID is defined"
      exit 1
    
    fi

上面就是一系列的逻辑判断，最主要的还是根据命令启动 Tomcat，最主要的其实就是 `start` 命令分支：

elif [ "$1" = "start" ] ; then
    
      if [ ! -z "$CATALINA_PID" ]; then
        if [ -f "$CATALINA_PID" ]; then
          if [ -s "$CATALINA_PID" ]; then
            echo "Existing PID file found during start."
            if [ -r "$CATALINA_PID" ]; then
              PID=`cat "$CATALINA_PID"`
              ps -p $PID >/dev/null 2>&1
              if [ $? -eq 0 ] ; then
                echo "Tomcat appears to still be running with PID $PID. Start aborted."
                echo "If the following process is not a Tomcat process, remove the PID file and try again:"
                ps -f -p $PID
                exit 1
              else
                echo "Removing/clearing stale PID file."
                rm -f "$CATALINA_PID" >/dev/null 2>&1
                if [ $? != 0 ]; then
                  if [ -w "$CATALINA_PID" ]; then
                    cat /dev/null > "$CATALINA_PID"
                  else
                    echo "Unable to remove or clear stale PID file. Start aborted."
                    exit 1
                  fi
                fi
              fi
            else
              echo "Unable to read PID file. Start aborted."
              exit 1
            fi
          else
            rm -f "$CATALINA_PID" >/dev/null 2>&1
            if [ $? != 0 ]; then
              if [ ! -w "$CATALINA_PID" ]; then
                echo "Unable to remove or write to empty PID file. Start aborted."
                exit 1
              fi
            fi
          fi
        fi
      fi
    
      shift
      touch "$CATALINA_OUT"
      if [ "$1" = "-security" ] ; then
        if [ $have_tty -eq 1 ]; then
          echo "Using Security Manager"
        fi
        shift
        eval $_NOHUP "\"$_RUNJAVA\"" "\"$CATALINA_LOGGING_CONFIG\"" $LOGGING_MANAGER "$JAVA_OPTS" "$CATALINA_OPTS" \
          -D$ENDORSED_PROP="\"$JAVA_ENDORSED_DIRS\"" \
          -classpath "\"$CLASSPATH\"" \
          -Djava.security.manager \
          -Djava.security.policy=="\"$CATALINA_BASE/conf/catalina.policy\"" \
          -Dcatalina.base="\"$CATALINA_BASE\"" \
          -Dcatalina.home="\"$CATALINA_HOME\"" \
          -Djava.io.tmpdir="\"$CATALINA_TMPDIR\"" \
          org.apache.catalina.startup.Bootstrap "$@" start \
          >> "$CATALINA_OUT" 2>&1 "&"
    
      else
        eval $_NOHUP "\"$_RUNJAVA\"" "\"$CATALINA_LOGGING_CONFIG\"" $LOGGING_MANAGER "$JAVA_OPTS" "$CATALINA_OPTS" \
          -D$ENDORSED_PROP="\"$JAVA_ENDORSED_DIRS\"" \
          -classpath "\"$CLASSPATH\"" \
          -Dcatalina.base="\"$CATALINA_BASE\"" \
          -Dcatalina.home="\"$CATALINA_HOME\"" \
          -Djava.io.tmpdir="\"$CATALINA_TMPDIR\"" \
          org.apache.catalina.startup.Bootstrap "$@" start \
          >> "$CATALINA_OUT" 2>&1 "&"
    
      fi
    
      if [ ! -z "$CATALINA_PID" ]; then
        echo $! > "$CATALINA_PID"
      fi
    
      echo "Tomcat started."

上面的最主要的核心代码以下代码：

eval $_NOHUP "\"$_RUNJAVA\"" "\"$CATALINA_LOGGING_CONFIG\"" $LOGGING_MANAGER "$JAVA_OPTS" "$CATALINA_OPTS" \
          -D$ENDORSED_PROP="\"$JAVA_ENDORSED_DIRS\"" \
          -classpath "\"$CLASSPATH\"" \
          -Djava.security.manager \
          -Djava.security.policy=="\"$CATALINA_BASE/conf/catalina.policy\"" \
          -Dcatalina.base="\"$CATALINA_BASE\"" \
          -Dcatalina.home="\"$CATALINA_HOME\"" \
          -Djava.io.tmpdir="\"$CATALINA_TMPDIR\"" \
          org.apache.catalina.startup.Bootstrap "$@" start \
          >> "$CATALINA_OUT" 2>&1 "&"

就是通过 `eval` shell 命令来执行`org.apache.catalina.startup.Bootstrap`。所以上一篇文章是通过 Bootstrap 类来启动项目的。在 idea 启动 Bootstrap 类，通过 `ps -ef | grep tomcat` 命令查看 Tomcat 。

/Library/Java/JavaVirtualMachines/jdk1.8.0_221.jdk/Contents/Home/bin/java 
    -agentlib:jdwp=transport=dt_socket,address=127.0.0.1:50592,suspend=y,server=n 
    -Dcatalina.home=/Users/carl/projects/idea/learn/apache-tomcat-8.5.54-src/source 
    -Dcatalina.base=/Users/carl/projects/idea/learn/apache-tomcat-8.5.54-src/source 
    -Djava.util.logging.manager=org.apache.juli.ClassLoaderLogManager 
    -Djava.util.logging.config.file=/Users/carl/projects/idea/learn/apache-tomcat-8.5.54-src/source/conf/logging.properties 
    -Dfile.encoding=UTF-8 -javaagent:/Users/carl/Library/Caches/IntelliJIdea2019.3/captureAgent/debugger-agent.jar 
    -classpath /Library/Java/JavaVirtualMachines/jdk1.8.0_221.jdk/Contents/Home/jre/lib/charsets.jar:/Library/Java/JavaVirtualMachines/jdk1.8.0_221.jdk/Contents/Home/jre/lib/deploy.jar:/Library/Java/JavaVirtualMachines/jdk1.8.0_221.jdk/Contents/Home/jre/lib/ext/cldrdata.jar:/Library/Java/JavaVirtualMachines/jdk1.8.0_221.jdk/Contents/Home/jre/lib/ext/dnsns.jar:/Library/Java/JavaVirtualMachines/jdk1.8.0_221.jdk/Contents/Home/jre/lib/ext/jaccess.jar:/Library/Java/JavaVirtualMachines/jdk1.8.0_221.jdk/Contents/Home/jre/lib/ext/jfxrt.jar:/Library/Java/JavaVirtualMachines/jdk1.8.0_221.jdk/Contents/Home/jre/lib/ext/localedata.jar:/Library/Java/JavaVirtualMachines/jdk1.8.0_221.jdk/Contents/Home/jre/lib/ext/nashorn.jar:/Library/Java/JavaVirtualMachines/jdk1.8.0_221.jdk/Contents/Home/jre/lib/ext/sunec.jar:/Library/Java/JavaVirtualMachines/jdk1.8.0_221.jdk/Contents/Home/jre/lib/ext/sunjce_provider.jar:/Library/Java/JavaVirtualMachines/jdk1.8.0_221.jdk/Contents/Home/jre/lib/ext/sunpkcs11.jar:/Library/Java/JavaVirtualMachines/jdk1.8.0_221.jdk/Contents/Home/jre/lib/ext/zipfs.jar:/Library/Java/JavaVirtualMachines/jdk1.8.0_221.jdk/Contents/Home/jre/lib/javaws.jar:/Library/Java/JavaVirtualMachines/jdk1.8.0_221.jdk/Contents/Home/jre/lib/jce.jar:/Library/Java/JavaVirtualMachines/jdk1.8.0_221.jdk/Contents/Home/jre/lib/jfr.jar:/Library/Java/JavaVirtualMachines/jdk1.8.0_221.jdk/Contents/Home/jre/lib/jfxswt.jar:/Library/Java/JavaVirtualMachines/jdk1.8.0_221.jdk/Contents/Home/jre/lib/jsse.jar:/Library/Java/JavaVirtualMachines/jdk1.8.0_221.jdk/Contents/Home/jre/lib/management
    -agent.jar:/Library/Java/JavaVirtualMachines/jdk1.8.0_221.jdk/Contents/Home/jre/lib/plugin.jar:/Library/Java/JavaVirtualMachines/jdk1.8.0_221.jdk/Contents/Home/jre/lib/resources.jar:/Library/Java/JavaVirtualMachines/jdk1.8.0_221.jdk/Contents/Home/jre/lib/rt.jar:/Library/Java/JavaVirtualMachines/jdk1.8.0_221.jdk/Contents/Home/lib/ant
    -javafx.jar:/Library/Java/JavaVirtualMachines/jdk1.8.0_221.jdk/Contents/Home/lib/dt.jar:/Library/Java/JavaVirtualMachines/jdk1.8.0_221.jdk/Contents/Home/lib/javafx-mx.jar:/Library/Java/JavaVirtualMachines/jdk1.8.0_221.jdk/Contents/Home/lib/jconsole.jar:/Library/Java/JavaVirtualMachines/jdk1.8.0_221.jdk/Contents/Home/lib/packager.jar:/Library/Java/JavaVirtualMachines/jdk1.8.0_221.jdk/Contents/Home/lib/sa-jdi.jar:/Library/Java/JavaVirtualMachines/jdk1.8.0_221.jdk/Contents/Home/lib/tools.jar:/Users/carl/projects/idea/learn/apache-tomcat-8.5.54-src/target/classes:/Users/carl/.m2/repository/javax/xml/jaxrpc-api/1.1/jaxrpc-api-1.1.jar:/Users/carl/.m2/repository/javax/xml/soap/javax.xml.soap-api/1.4.0/javax.xml.soap-api-1.4.0.jar:/Users/carl/.m2/repository/wsdl4j/wsdl4j/1.6.2/wsdl4j-1.6.2.jar:/Users/carl/.m2/repository/org/eclipse/jdt/core/compiler/ecj/4.5.1/ecj-4.5.1.jar:/Users/carl/.m2/repository/org/apache/ant/ant/1.7.0/ant-1.7.0.jar:/Users/carl/.m2/repository/org/apache/ant/ant-launcher/1.7.0/ant-launcher-1.7.0.jar:/Users/carl/.m2/repository/org/easymock/easymock/3.4/easymock-3.4.jar:/Users/carl/.m2/repository/org/objenesis/objenesis/2.2/objenesis-2.2.jar:/Applications/IntelliJ IDEA.app/Contents/lib/idea_rt.jar 
    org.apache.catalina.startup.Bootstrap

和上面的通过 shell 命令类似，都是通过：

java -Dkey=值... org.apache.catalina.startup.Bootstrap(包含 main 方法的类)