Nginx学习笔记（八） Nginx进程启动分析

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
.cv = ngx_cond_init(cycle->log);

if (ngx_threads
.cv == NULL) {
/* fatal */
exit(2);
}

if (ngx_create_thread((ngx_tid_t *) &ngx_threads
.tid,
ngx_worker_thread_cycle,
(void *) &ngx_threads
, 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
.pid == -1) {
continue;
}
if (n == ngx_process_slot) {
continue;
}
if (ngx_processes
.channel[1] == -1) {
continue;
}
if (close(ngx_processes
.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);
}
}