daemon_start.c

创建守护进程的例子

/*****************************************************************************
 * File            : daemon.c                                                *
 * System Name     : StarRing                                                *
 * VERSION         : 1.0                                                     *
 * LANGUAGE        : ANSIC                                                   *
 * OS & ENVIROMENT : Linux                                                   * 
 *                                                                           *
 * DESCRIPTION     : function to init daemon process                         *
 *                                                                           *
 * HISTORY:                                                                  *
 * MM/DD/YYYY      ADDRESS          PROGRAMMER            DESCRIPTION        *
 *---------------------------------------------------------------------------*
 * 22/08/2002      CHENGDU          ChenBo               Creation           *
 *                                                                           *
 *****************************************************************************/
#include <chenpubhead.h>

int daemon_start( char *workdir )
{
    pid_t	pid;

    if ( (pid=fork()) < 0 ) {  /* create 1st child */
        Errlog( __FILE__,__LINE__, "fork()" );
        return E_FAIL;
    }
    if ( pid > 0 ) 
        exit( 0 );

    /* 1st child continue */
    setsid();    /* become session leader */

    signal(SIGHUP, SIG_IGN);
    if ( (pid = fork()) < 0) { /* create 2nd child */
        Errlog( __FILE__,__LINE__, "fork()" );
        return E_FAIL;
    }

    if ( pid > 0 ) /* 1st child exit */
        exit( 0 );
    
    /* 2nd child continue */
    umask( 0 );

    if ( workdir != NULL )
        chdir( workdir );

    return E_OK;
}