nginx 通過Signal傳送控制訊號

nginx 通過signal傳送控制訊號，類似nginx -s reload的流程如下：

1 訊號結構體

// 訊號結構體

typedef struct ngx_signal_t;

int ngx_cdecl

main(int argc, char *const *ar**)
...}

static ngx_int_t

ngx_get_options(int argc, char *const *ar**)
else if (ar**[++i]) else 
if (ngx_strcmp(ngx_signal, "stop") == 0
|| ngx_strcmp(ngx_signal, "quit") == 0
|| ngx_strcmp(ngx_signal, "reopen") == 0
|| ngx_strcmp(ngx_signal, "reload") == 0)
ngx_log_stderr(0, "invalid option: \"-s %s\"", ngx_signal);
return ngx_error;
default:
ngx_log_stderr(0, "invalid option: \"%c\"", *(p - 1));
return ngx_error;}}
...return ngx_ok;
}

4 ngx_signal_process()函式

① 開啟工作程序檔案，讀取pid

② 呼叫ngx_os_signal_process函式處理

ngx_int_t

ngx_signal_process(ngx_cycle_t *cycle, char *sig)
n = ngx_read_file(&file, buf, ngx_int64_len + 2, 0);
if (ngx_close_file(file.fd) == ngx_file_error) 
if (n == ngx_error) 
while (n-- && (buf[n] == cr || buf[n] == lf)) 
pid = ngx_atoi(buf, ++n);
if (pid == (ngx_pid_t) ngx_error) 
return ngx_os_signal_process(cycle, sig, pid);
}

遍歷signals陣列，根據給定訊號name，找到對應signo，呼叫kill命令，向該pid傳送signo號訊號

ngx_int_t

ngx_os_signal_process(ngx_cycle_t *cycle, char *name, ngx_pid_t pid)
ngx_log_error(ngx_log_alert, cycle->log, ngx_errno,
"kill(%p, %d) failed", pid, sig->signo);}}
return 1;
}

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