Linux server daemon + Automatic startup + service configuration notes

From: http://www.cppblog.com/sunicdavy/archive/2012/02/28/166680.html1.1 add daemon for Process

Reference http://yubosun.akcms.com/tech/linux-daemon-program.htm

   1:  #include <unistd.h> 

   2:  #include <signal.h> 

   3:  #include <sys/types.h> 

   4:  #include <sys/stat.h> 

   5:  #include <stdio.h> 

   6:  #include <stdlib.h>

   7:   

   8:  #ifndef NOFILE 

   9:  #define NOFILE 3 

  10:  #endif

  11:   

  12:  void init_daemon() 

  13:  { 

  14:          int pid; 

  15:          int i; 

16: If (pid = fork () Exit (0); // parent process, exit

  17:   

18: else if (PID <0) Exit (1); // fork failed

  19:   

20:/* continue executing the sub-process */

21: setsid (); // create a new session group. The sub-process becomes the group leader and is separated from the control terminal.

  22:   

23:/* prevent sub-processes (Team Leaders) from obtaining control terminals */

24: If (pid = fork () Exit (0); // parent process, exit

  25:   

26: else if (PID <0) Exit (1); // fork error, exit

  27:   

28:/* the second sub-process continues to be executed. The second sub-process is no longer a session group leader */

  29:   

30: // for (I = 0; I <nofile; I ++)/* close open file descriptor */

  31:          //{ 

  32:          //close(i); 

  33:          //} 

34: chdir ("/tmp");/* switch the working directory */

35: umask (0);/* reset the file creation mask */

  36:          return; 

  37:  }

  38:   

  39:  int main(int argc, char* argv[])

  40:  {    

  41:      FILE *fp; 

  42:   

43: Signal (sigchld, sig_ign);/* ignore the subprocess end signal to prevent zombie processes */

  44:   

  45:      init_daemon(); 

  46:   

  47:      while(1) 

  48:      { 

  49:              sleep(1);

  50:              

51: // note: the log is written to this directory.

  52:              if((fp = fopen("/var/tmp/test.log", "a")) != NULL) 

  53:              { 

  54:                      fprintf(fp, "%s\n", "test message"); 

  55:                      fclose(fp); 

  56:              } 

  57:      } 

  58:   

  59:      return 0;

  60:  }

1.2 write service scripts

Reference http://blog.sina.com.cn/s/blog_57421ff80100c7nn.html

The red text is the part to be filled in, and the file header can be optional

   1:  #!/bin/bash

   2:   

   3:  # chkconfig: 3 3 1

   4:   

   5:  # description: web kill center

   6:   

   7:  EXEC_PATH=/usr/local/bin

   8:   

   9:  EXEC=CenterServiced

  10:   

  11:  PID_FILE=/var/run/CenterServiced.pid

  12:   

  13:  DAEMON=/usr/local/bin/CenterServiced

  14:   

  15:  if ! [ -x $EXEC_PATH/$EXEC ] ; then

  16:   

  17:  echo "ERROR: $EXEC_PATH/$EXEC not found"

  18:   

  19:  exit 1

  20:   

  21:  fi

  22:   

  23:  stop()

  24:   

  25:  {

  26:   

  27:  echo "Stoping $EXEC ..."

  28:   

  29:  killall $DAEMON >/dev/null

  30:   

  31:  echo "Shutting down $EXEC: [ OK ]"

  32:   

  33:  }

  34:   

  35:  start()

  36:   

  37:  {

  38:   

  39:  echo "Starting $EXEC ..."

  40:   

  41:  $DAEMON > /dev/null &

  42:   

  43:  echo "Starting $EXEC: [ OK ]"

  44:   

  45:  }

  46:   

  47:  restart()

  48:   

  49:  {

  50:   

  51:  stop

  52:   

  53:  start

  54:   

  55:  }

  56:   

  57:  case "$1" in

  58:   

  59:  start)

  60:   

  61:  start

  62:   

  63:  ;;

  64:   

  65:  stop)

  66:   

  67:  stop

  68:   

  69:  ;;

  70:   

  71:  restart)

  72:   

  73:  restart

  74:   

  75:  ;;

  76:   

  77:  status)

  78:   

  79:  status -p $PID_FILE $DAEMON

  80:   

  81:  ;;

  82:   

  83:  *)

  84:   

  85:  echo "Usage: service $EXEC {start|stop|restart|status}"

  86:   

  87:  exit 1

  88:   

  89:  esac

  90:   

  91:  exit $?

  92:   

1.3 create a service

Reference http://hi.baidu.com/guanxiansun/blog/item/b4c7dcf55f6011e47709d724.html

Copy the service file to/etc/init. d and remove the extension. The file name is the service name.

Chmod + X./wkcenter

If startup is not set, the service cannot be found and operated.

1.4 set the startup sequence

Create startup Link

Ln/etc/init. d/wkcenter/etc/rc3.d/s03wkcenter

Create close link

Ln/etc/init. d/wkcenter/etc/rc0.d/k03wkcenter

1.5 Add a service

Chkconfig -- add wkcenter

Check whether the service exists

Chkconfig -- list | grep wkcenter

View service status

Chkconfig wkcenter on

Note: Make sure that wkcenter is enabled in any or part of 2, 3, 4, 5. It must be green. The gray text indicates that the service cannot be started or has other problems.

1.6 Test

Temporarily enable command Test

Service wkcenter start

1.7 QA

Reference link: http://blog.526net.com /? P = 1706

1. Do not place the service in the user's home directory. It is best to place the service in the/usr/local/bin directory and write the log to var. Otherwise, the service test is normal but cannot be started automatically.

2. in Linux, the life cycle of the program started by the parent process follows the parent process. The parent process can be a terminal. Once the parent process is terminated, all child processes must end. therefore, the daemon process must be detached from the parent process to avoid being controlled by the lifecycle of the parent process.