service XXX restart的执行流程

当我们执行service ssh restart时，做了些什么？
/etc/rc.d/init.d/sshd代码如下
#!/bin/sh
if [ ! -x /usr/sbin/sshd ]
then
    exit 0
fi
if [ "$1" = "stop" -o "$1" = "restart" ]
then
    echo "Stopping the ssh server: "
    killall sshd
fi
if [ "$1" = "start" -o "$1" = "restart" ]
then
    # assume if one key is missing, all are
    if [ ! -f /etc/ssh/ssh_host_key ]
    then
        echo "Generating keys for the ssh server: "
        ssh-keygen -q -t rsa1 -f /etc/ssh/ssh_host_key  -C '' -N ''
        ssh-keygen -q -t rsa -f /etc/ssh/ssh_host_rsa_key  -C '' -N ''
        ssh-keygen -q -t dsa -f /etc/ssh/ssh_host_dsa_key  -C '' -N ''
    fi
    for i in ssh_host_key ssh_host_rsa_key ssh_host_dsa_key
    do
        chmod 600 /etc/ssh/$i
    done
    echo "Starting the ssh server: "
    /usr/sbin/sshd
fi
service smb restart
#!/bin/sh
case "$1" in
  start)
    echo -n "Starting SMB services: "
    nmbd $NMBD_ARGS
    sleep 1
    smbd $SMBD_ARGS
    ;;
  stop)
    echo -n "Shutting down SMB services: "
    killall smbd
    killall nmbd
    ;;
  *)
    echo "Usage: smb {start|stop}"
    exit 1
esac

当我们执行service ssh restart时，做了些什么？
/etc/rc.d/init.d/sshd代码如下
#!/bin/sh
if [ ! -x /usr/sbin/sshd ]
then
    exit 0
fi
if [ "$1" = "stop" -o "$1" = "restart" ]
then
    echo "Stopping the ssh server: "
    killall sshd
fi
if [ "$1" = "start" -o "$1" = "restart" ]
then
    # assume if one key is missing, all are
    if [ ! -f /etc/ssh/ssh_host_key ]
    then
        echo "Generating keys for the ssh server: "
        ssh-keygen -q -t rsa1 -f /etc/ssh/ssh_host_key  -C '' -N ''
        ssh-keygen -q -t rsa -f /etc/ssh/ssh_host_rsa_key  -C '' -N ''
        ssh-keygen -q -t dsa -f /etc/ssh/ssh_host_dsa_key  -C '' -N ''
    fi
    for i in ssh_host_key ssh_host_rsa_key ssh_host_dsa_key
    do
        chmod 600 /etc/ssh/$i
    done
    echo "Starting the ssh server: "
    /usr/sbin/sshd
fi
service smb restart
#!/bin/sh
case "$1" in
  start)
    echo -n "Starting SMB services: "
    nmbd $NMBD_ARGS
    sleep 1
    smbd $SMBD_ARGS
    ;;
  stop)
    echo -n "Shutting down SMB services: "
    killall smbd
    killall nmbd
    ;;
  *)
    echo "Usage: smb {start|stop}"
    exit 1
esac

当我们执行service ssh restart时，做了些什么？
/etc/rc.d/init.d/sshd代码如下
#!/bin/sh

if [ ! -x /usr/sbin/sshd ]
then
    exit 0
fi

if [ "$1" = "stop" -o "$1" = "restart" ]
then
    echo "Stopping the ssh server: "
    killall sshd
fi

if [ "$1" = "start" -o "$1" = "restart" ]
then
    # assume if one key is missing, all are
    if [ ! -f /etc/ssh/ssh_host_key ]
    then
        echo "Generating keys for the ssh server: "
        ssh-keygen -q -t rsa1 -f /etc/ssh/ssh_host_key  -C '' -N ''
        ssh-keygen -q -t rsa -f /etc/ssh/ssh_host_rsa_key  -C '' -N ''
        ssh-keygen -q -t dsa -f /etc/ssh/ssh_host_dsa_key  -C '' -N ''
    fi
    for i in ssh_host_key ssh_host_rsa_key ssh_host_dsa_key
    do
        chmod 600 /etc/ssh/$i
    done
    echo "Starting the ssh server: "
    /usr/sbin/sshd
fi

service smb restart
#!/bin/sh

case "$1" in
  start)
    echo -n "Starting SMB services: "
    nmbd $NMBD_ARGS
    sleep 1
    smbd $SMBD_ARGS
    ;;
  stop)
    echo -n "Shutting down SMB services: "
    killall smbd
    killall nmbd
    ;;
  *)
    echo "Usage: smb {start|stop}"
    exit 1
esac