Nginx进程启动分析
worker子进程的执行循环的函数是ngx_worker_process_cycle (src/os/unix/ngx_process_cycle.c)。
其中，捕获事件、分发事件的函数是ngx_process_events_and_timers(cycle);
static void ngx_worker_process_cycle(ngx_cycle_t *cycle, void *data) { ngx_int_t worker = (intptr_t) data; ngx_uint_t i; ngx_connection_t *c; ngx_process = NGX_PROCESS_WORKER;//将全局变量ngx_process设置为worker进程 ngx_worker_process_init(cycle, worker);//对worker进程进行初始化操作 ngx_setproctitle("worker process"); #if (NGX_THREADS) { ngx_int_t n; ngx_err_t err; ngx_core_conf_t *ccf; ccf = (ngx_core_conf_t *) ngx_get_conf(cycle->conf_ctx, ngx_core_module); if (ngx_threads_n) { if (ngx_init_threads(ngx_threads_n, ccf->thread_stack_size, cycle) == NGX_ERROR) { /* fatal */ exit(2); } err = ngx_thread_key_create(&ngx_core_tls_key); if (err != 0) { ngx_log_error(NGX_LOG_ALERT, cycle->log, err, ngx_thread_key_create_n " failed"); /* fatal */ exit(2); } for (n = 0; n < ngx_threads_n; n++) { ngx_threads[n].cv = ngx_cond_init(cycle->log); if (ngx_threads[n].cv == NULL) { /* fatal */ exit(2); } if (ngx_create_thread((ngx_tid_t *) &ngx_threads[n].tid, ngx_worker_thread_cycle, (void *) &ngx_threads[n], cycle->log) != 0) { /* fatal */ exit(2); } } } } #endif for ( ;; ) { //ngx_exiting是在worker进程收到SIGQUIT信号后设置的 if (ngx_exiting) { c = cycle->connections; //退出前，处理每个连接上的事件 for (i = 0; i < cycle->connection_n; i++) { /* THREAD: lock */ if (c[i].fd != -1 && c[i].idle) { c[i].close = 1; c[i].read->handler(c[i].read); } } if (ngx_event_timer_rbtree.root == ngx_event_timer_rbtree.sentinel) { ngx_log_error(NGX_LOG_NOTICE, cycle->log, 0, "exiting"); ngx_worker_process_exit(cycle); } } ngx_log_debug0(NGX_LOG_DEBUG_EVENT, cycle->log, 0, "worker cycle"); //处理各种事件，主要的处理函数！！！ ngx_process_events_and_timers(cycle); //worker进程收到了SIGINT信号 if (ngx_terminate) { ngx_log_error(NGX_LOG_NOTICE, cycle->log, 0, "exiting"); ngx_worker_process_exit(cycle); } //进程收到了SIGQUIT信号，ngx_exiting设置为1，同时关闭监听套接口 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_close_listening_sockets(cycle); ngx_exiting = 1; } } //worker进程收到了SIGUSR1信号 if (ngx_reopen) { ngx_reopen = 0; ngx_log_error(NGX_LOG_NOTICE, cycle->log, 0, "reopening logs"); ngx_reopen_files(cycle, -1); } } }
其中初始化函数分析，如下：
static void ngx_worker_process_init(ngx_cycle_t *cycle, ngx_int_t worker) { sigset_t set; uint64_t cpu_affinity; ngx_int_t n; ngx_uint_t i; struct rlimit rlmt; ngx_core_conf_t *ccf; ngx_listening_t *ls; //配置一些环境变量 if (ngx_set_environment(cycle, NULL) == NULL) { /* fatal */ exit(2); } //获取配置信息 ccf = (ngx_core_conf_t *) ngx_get_conf(cycle->conf_ctx, ngx_core_module); if (worker >= 0 && ccf->priority != 0) { if (setpriority(PRIO_PROCESS, 0, ccf->priority) == -1) { ngx_log_error(NGX_LOG_ALERT, cycle->log, ngx_errno, "setpriority(%d) failed", ccf->priority); } } if (ccf->rlimit_nofile != NGX_CONF_UNSET) { rlmt.rlim_cur = (rlim_t) ccf->rlimit_nofile; rlmt.rlim_max = (rlim_t) ccf->rlimit_nofile; if (setrlimit(RLIMIT_NOFILE, &rlmt) == -1) { ngx_log_error(NGX_LOG_ALERT, cycle->log, ngx_errno, "setrlimit(RLIMIT_NOFILE, %i) failed", ccf->rlimit_nofile); } } if (ccf->rlimit_core != NGX_CONF_UNSET) { rlmt.rlim_cur = (rlim_t) ccf->rlimit_core; rlmt.rlim_max = (rlim_t) ccf->rlimit_core; if (setrlimit(RLIMIT_CORE, &rlmt) == -1) { ngx_log_error(NGX_LOG_ALERT, cycle->log, ngx_errno, "setrlimit(RLIMIT_CORE, %O) failed", ccf->rlimit_core); } } #ifdef RLIMIT_SIGPENDING if (ccf->rlimit_sigpending != NGX_CONF_UNSET) { rlmt.rlim_cur = (rlim_t) ccf->rlimit_sigpending; rlmt.rlim_max = (rlim_t) ccf->rlimit_sigpending; if (setrlimit(RLIMIT_SIGPENDING, &rlmt) == -1) { ngx_log_error(NGX_LOG_ALERT, cycle->log, ngx_errno, "setrlimit(RLIMIT_SIGPENDING, %i) failed", ccf->rlimit_sigpending); } } #endif //设置UID GROUPUID if (geteuid() == 0) { if (setgid(ccf->group) == -1) { ngx_log_error(NGX_LOG_EMERG, cycle->log, ngx_errno, "setgid(%d) failed", ccf->group); /* fatal */ exit(2); } if (initgroups(ccf->username, ccf->group) == -1) { ngx_log_error(NGX_LOG_EMERG, cycle->log, ngx_errno, "initgroups(%s, %d) failed", ccf->username, ccf->group); } if (setuid(ccf->user) == -1) { ngx_log_error(NGX_LOG_EMERG, cycle->log, ngx_errno, "setuid(%d) failed", ccf->user); /* fatal */ exit(2); } } //设置CPU亲和性 if (worker >= 0) { cpu_affinity = ngx_get_cpu_affinity(worker); if (cpu_affinity) { ngx_setaffinity(cpu_affinity, cycle->log); } } #if (NGX_HAVE_PR_SET_DUMPABLE) /* allow coredump after setuid() in Linux 2.4.x */ if (prctl(PR_SET_DUMPABLE, 1, 0, 0, 0) == -1) { ngx_log_error(NGX_LOG_ALERT, cycle->log, ngx_errno, "prctl(PR_SET_DUMPABLE) failed"); } #endif //切换工作目录 if (ccf->working_directory.len) { if (chdir((char *) ccf->working_directory.data) == -1) { ngx_log_error(NGX_LOG_ALERT, cycle->log, ngx_errno, "chdir("%s") failed", ccf->working_directory.data); /* fatal */ exit(2); } } sigemptyset(&set); //清除所有信号 if (sigprocmask(SIG_SETMASK, &set, NULL) == -1) { ngx_log_error(NGX_LOG_ALERT, cycle->log, ngx_errno, "sigprocmask() failed"); } /* * disable deleting previous events for the listening sockets because * in the worker processes there are no events at all at this point */ ls = cycle->listening.elts;
//清除监听socket上以前的事件 for (i = 0; i < cycle->listening.nelts; i++) { ls[i].previous = NULL; } //对所有模块进行初始化 for (i = 0; ngx_modules[i]; i++) { if (ngx_modules[i]->init_process) { if (ngx_modules[i]->init_process(cycle) == NGX_ERROR) { /* fatal */ exit(2); } } } //将其他进程的channel[1]关闭，自己的channel[0]关闭 for (n = 0; n < ngx_last_process; n++) { if (ngx_processes[n].pid == -1) { continue; } if (n == ngx_process_slot) { continue; } if (ngx_processes[n].channel[1] == -1) { continue; } if (close(ngx_processes[n].channel[1]) == -1) { ngx_log_error(NGX_LOG_ALERT, cycle->log, ngx_errno, "close() channel failed"); } } if (close(ngx_processes[ngx_process_slot].channel[0]) == -1) { ngx_log_error(NGX_LOG_ALERT, cycle->log, ngx_errno, "close() channel failed"); } #if 0 ngx_last_process = 0; #endif //给ngx_channel注册一个读事件处理函数 if (ngx_add_channel_event(cycle, ngx_channel, NGX_READ_EVENT, ngx_channel_handler)== NGX_ERROR){ /* fatal */ exit(2); } }