nginx -s reload原理

处理信号的全局变量数组：

ngx_signal_t signals[] = {

{ ngx_signal_value(NGX_RECONFIGURE_SIGNAL),

"SIG" ngx_value(NGX_RECONFIGURE_SIGNAL),

"reload",

ngx_signal_handler },

{ ngx_signal_value(NGX_REOPEN_SIGNAL),

"SIG" ngx_value(NGX_REOPEN_SIGNAL),

"reopen",

ngx_signal_handler },

{ ngx_signal_value(NGX_NOACCEPT_SIGNAL),

"SIG" ngx_value(NGX_NOACCEPT_SIGNAL),

"",

ngx_signal_handler },

{ ngx_signal_value(NGX_TERMINATE_SIGNAL),

"SIG" ngx_value(NGX_TERMINATE_SIGNAL),

"stop",

ngx_signal_handler },

{ ngx_signal_value(NGX_SHUTDOWN_SIGNAL),

"SIG" ngx_value(NGX_SHUTDOWN_SIGNAL),

"quit",

ngx_signal_handler },

...

}

#define NGX_SHUTDOWN_SIGNAL QUIT

#define NGX_TERMINATE_SIGNAL TERM

#define NGX_NOACCEPT_SIGNAL WINCH

#define NGX_RECONFIGURE_SIGNAL HUP

main

--ngx_get_options // ngx_signal设置为"reload",ngx_process = NGX_PROCESS_SIGNALLER;

--ngx_signal_process

--ngx_os_signal_process // 入参的name就是ngx_signal，即"reload"

--kill(pid, sig->signo) // 对master进程pid执行Kill -SIGHUP,

--ngx_signal_handler // case ngx_signal_value(NGX_RECONFIGURE_SIGNAL):

// ngx_reconfigure = 1;

--ngx_master_process_cycle

--ngx_start_worker_processes(cycle, ccf->worker_processes,

NGX_PROCESS_JUST_RESPAWN); // 启新的worker

--ngx_signal_worker_processes(cycle,

ngx_signal_value(NGX_SHUTDOWN_SIGNAL)); // 关闭老的worker

--kill(ngx_processes[i].pid, signo)

--ngx_signal_handler // case ngx_signal_value(NGX_SHUTDOWN_SIGNAL):

// ngx_quit = 1;

ngx_worker_process_cycle

{

...

if (ngx_quit) {

ngx_quit = 0;

ngx_log_error(NGX_LOG_NOTICE, cycle->log, 0,

"gracefully shutting down");

ngx_setproctitle("worker process is shutting down");

if (!ngx_exiting) {

ngx_exiting = 1;

ngx_set_shutdown_timer(cycle);

ngx_close_listening_sockets(cycle); // 关闭监听句柄

ngx_close_idle_connections(cycle); // 关闭空闲链接

}

}

...

}