nginx 소스 코드 분석 1 (main 함수 분석)

//1.  、  、    、ssl    
//2.       
//3.OS     
//4.       
//5.       
//6.           
//7.      
//8.  listen   
//9.       
//10.  worker  
int ngx_cdecl
main(int argc, char *const *argv)
{
    ngx_int_t         i;
    ngx_log_t        *log;
    ngx_cycle_t      *cycle, init_cycle;
    ngx_core_conf_t  *ccf;

#if (NGX_FREEBSD)
    ngx_debug_init();
#endif

    if (ngx_strerror_init() != NGX_OK) {
        return 1;
    }

    //         ，     nginx -v   ngx_show_version    1
    if (ngx_get_options(argc, argv) != NGX_OK) {
   //             ，             （   -v ，  
   //ngx_show_version=1），            
        return 1;
    }

    if (ngx_show_version) {
       //      ，         
        ngx_write_stderr("nginx version: " NGINX_VER NGX_LINEFEED);

        if (ngx_show_help) {
            ngx_write_stderr(
                "Usage: nginx [-?hvVtq] [-s signal] [-c filename] "
                             "[-p prefix] [-g directives]" NGX_LINEFEED
                             NGX_LINEFEED
                "Options:" NGX_LINEFEED
                "  -?,-h         : this help" NGX_LINEFEED
                "  -v            : show version and exit" NGX_LINEFEED
                "  -V            : show version and configure options then exit"
                                   NGX_LINEFEED
                "  -t            : test configuration and exit" NGX_LINEFEED
                "  -q            : suppress non-error messages "
                                   "during configuration testing" NGX_LINEFEED
                "  -s signal     : send signal to a master process: "
                                   "stop, quit, reopen, reload" NGX_LINEFEED
#ifdef NGX_PREFIX
                "  -p prefix     : set prefix path (default: "
                                   NGX_PREFIX ")" NGX_LINEFEED
#else
                "  -p prefix     : set prefix path (default: NONE)" NGX_LINEFEED
#endif
                "  -c filename   : set configuration file (default: "
                                   NGX_CONF_PATH ")" NGX_LINEFEED
                "  -g directives : set global directives out of configuration "
                                   "file" NGX_LINEFEED NGX_LINEFEED
                );
        }

        if (ngx_show_configure) {
            ngx_write_stderr(
#ifdef NGX_COMPILER
                "built by " NGX_COMPILER NGX_LINEFEED
#endif
#if (NGX_SSL)
#ifdef SSL_CTRL_SET_TLSEXT_HOSTNAME
                "TLS SNI support enabled" NGX_LINEFEED
#else
                "TLS SNI support disabled" NGX_LINEFEED
#endif
#endif
                "configure arguments:" NGX_CONFIGURE NGX_LINEFEED);
        }

        if (!ngx_test_config) {
            return 0;
        }
    }

    /* TODO */ ngx_max_sockets = -1;

    //   nginx       
    ngx_time_init();

#if (NGX_PCRE)
    ngx_regex_init();
#endif

	//master pid，       ID
    ngx_pid = ngx_getpid();
    //      ，       
    log = ngx_log_init(ngx_prefix);
    if (log == NULL) {
        return 1;
    }

    /* STUB */
#if (NGX_OPENSSL)
    ngx_ssl_init(log);  //     ssl，            
#endif

    /*
     * init_cycle->log is required for signal handlers and
     * ngx_process_options()
     */

    ngx_memzero(&init_cycle, sizeof(ngx_cycle_t));
    init_cycle.log = log;
    ngx_cycle = &init_cycle;
    //  cycle    1024B    
    init_cycle.pool = ngx_create_pool(1024, log);
    if (init_cycle.pool == NULL) {
        return 1;
    }
    //           
    if (ngx_save_argv(&init_cycle, argc, argv) != NGX_OK) {
        return 1;
    }
    //    init_cycle     : conf_file，prefix，conf_prefix   
    if (ngx_process_options(&init_cycle) != NGX_OK) {
        return 1;
    }
    //          ，       ngx_pagesize,ngx_cacheline_size,     ngx_max_sockets 
    if (ngx_os_init(log) != NGX_OK) {  //   ngx_os_init              
        return 1;
    }

    /*
     * ngx_crc32_table_init() requires ngx_cacheline_size set in ngx_os_init()
     */
    //    CRC ，    ，        ，   
    if (ngx_crc32_table_init() != NGX_OK) {
        return 1;
    }
     //   sockets,    socket    init_cycle listening  
    if (ngx_add_inherited_sockets(&init_cycle) != NGX_OK) {
        return 1;
    }
    //       ，          （  ）
    ngx_max_module = 0;
    for (i = 0; ngx_modules[i]; i++) {  //     ngx_modules        ，[ngx_core_module,ngx_errlog_module,ngx_conf_moduel]
        ngx_modules[i]->index = ngx_max_module++;
    }

    //  ngx_cycle       ,   nginx      ！
    cycle = ngx_init_cycle(&init_cycle);
    if (cycle == NULL) {
        if (ngx_test_config) {
            ngx_log_stderr(0, "configuration file %s test failed",
                           init_cycle.conf_file.data);
        }

        return 1;
    }

    if (ngx_test_config) {
        if (!ngx_quiet_mode) {
            ngx_log_stderr(0, "configuration file %s test is successful",
                           cycle->conf_file.data);
        }

        return 0;
    }
    //            ，  ，  ngx_signal_process  
    if (ngx_signal) {
        return ngx_signal_process(cycle, ngx_signal);
    }

    ngx_os_status(cycle->log);

    ngx_cycle = cycle;

    ccf = (ngx_core_conf_t *) ngx_get_conf(cycle->conf_ctx, ngx_core_module);

    if (ccf->master && ngx_process == NGX_PROCESS_SINGLE) {
        ngx_process = NGX_PROCESS_MASTER;
    }

#if !(NGX_WIN32)

    if (ngx_init_signals(cycle->log) != NGX_OK) {
        return 1;
    }

    if (!ngx_inherited && ccf->daemon) {
        if (ngx_daemon(cycle->log) != NGX_OK) { //   daemon  ，         
            return 1;
        }

        ngx_daemonized = 1;
    }

    if (ngx_inherited) {
        ngx_daemonized = 1;
    }

#endif
    //         
    if (ngx_create_pidfile(&ccf->pid, cycle->log) != NGX_OK) {
        return 1;
    }

    if (cycle->log->file->fd != ngx_stderr) {

        if (ngx_set_stderr(cycle->log->file->fd) == NGX_FILE_ERROR) {
            ngx_log_error(NGX_LOG_EMERG, cycle->log, ngx_errno,
                          ngx_set_stderr_n " failed");
            return 1;
        }
    }

    if (log->file->fd != ngx_stderr) {
        if (ngx_close_file(log->file->fd) == NGX_FILE_ERROR) {
            ngx_log_error(NGX_LOG_ALERT, cycle->log, ngx_errno,
                          ngx_close_file_n " built-in log failed");
        }
    }

    ngx_use_stderr = 0;

    if (ngx_process == NGX_PROCESS_SINGLE) {
        ngx_single_process_cycle(cycle);   //   

    } else {
        ngx_master_process_cycle(cycle);    //   ，master      ，                。
    }

    return 0;
}