static ngx_int_t
ngx_event_process_init(ngx_cycle_t *cycle)
{
ngx_uint_t m, i;
ngx_event_t *rev, *wev;
ngx_listening_t *ls;
ngx_connection_t *c, *next, *old;
ngx_core_conf_t *ccf;
ngx_event_conf_t *ecf;
ngx_event_module_t *module;
ccf = (ngx_core_conf_t *) ngx_get_conf(cycle->conf_ctx, ngx_core_module);
ecf = ngx_event_get_conf(cycle->conf_ctx, ngx_event_core_module);
if (ccf->master && ccf->worker_processes > 1 && ecf->accept_mutex) {
ngx_use_accept_mutex = 1;
ngx_accept_mutex_held = 0;
ngx_accept_mutex_delay = ecf->accept_mutex_delay;
} else {
ngx_use_accept_mutex = 0;
}
#if (NGX_WIN32)
/*
* disable accept mutex on win32 as it may cause deadlock if
* grabbed by a process which can't accept connections
*/
ngx_use_accept_mutex = 0;
#endif
#if (NGX_THREADS)
ngx_posted_events_mutex = ngx_mutex_init(cycle->log, 0);
if (ngx_posted_events_mutex == NULL) {
return NGX_ERROR;
}
#endif
if (ngx_event_timer_init(cycle->log) == NGX_ERROR) {
return NGX_ERROR;
}
for (m = 0; ngx_modules[m]; m++) {
if (ngx_modules[m]->type != NGX_EVENT_MODULE) {
continue;
}
if (ngx_modules[m]->ctx_index != ecf->use) {
continue;
}
module = ngx_modules[m]->ctx;
if (module->actions.init(cycle, ngx_timer_resolution) != NGX_OK) {
/* fatal */
exit(2);
}
break;
}
#if !(NGX_WIN32)
if (ngx_timer_resolution && !(ngx_event_flags & NGX_USE_TIMER_EVENT)) {
struct sigaction sa;
struct itimerval itv;
ngx_memzero(&sa, sizeof(struct sigaction));
sa.sa_handler = ngx_timer_signal_handler;
sigemptyset(&sa.sa_mask);
if (sigaction(SIGALRM, &sa, NULL) == -1) {
ngx_log_error(NGX_LOG_ALERT, cycle->log, ngx_errno,
"sigaction(SIGALRM) failed");
return NGX_ERROR;
}
itv.it_interval.tv_sec = ngx_timer_resolution / 1000;
itv.it_interval.tv_usec = (ngx_timer_resolution % 1000) * 1000;
itv.it_value.tv_sec = ngx_timer_resolution / 1000;
itv.it_value.tv_usec = (ngx_timer_resolution % 1000 ) * 1000;
if (setitimer(ITIMER_REAL, &itv, NULL) == -1) {
ngx_log_error(NGX_LOG_ALERT, cycle->log, ngx_errno,
"setitimer() failed");
}
}
if (ngx_event_flags & NGX_USE_FD_EVENT) {
struct rlimit rlmt;
if (getrlimit(RLIMIT_NOFILE, &rlmt) == -1) {
ngx_log_error(NGX_LOG_ALERT, cycle->log, ngx_errno,
"getrlimit(RLIMIT_NOFILE) failed");
return NGX_ERROR;
}
cycle->files_n = (ngx_uint_t) rlmt.rlim_cur;
cycle->files = ngx_calloc(sizeof(ngx_connection_t *) * cycle->files_n,
cycle->log);
if (cycle->files == NULL) {
return NGX_ERROR;
}
}
#endif
cycle->connections =
ngx_alloc(sizeof(ngx_connection_t) * cycle->connection_n, cycle->log);
if (cycle->connections == NULL) {
return NGX_ERROR;
}
c = cycle->connections;
cycle->read_events = ngx_alloc(sizeof(ngx_event_t) * cycle->connection_n,
cycle->log);
if (cycle->read_events == NULL) {
return NGX_ERROR;
}
rev = cycle->read_events;
for (i = 0; i < cycle->connection_n; i++) {
rev[i].closed = 1;
rev[i].instance = 1;
#if (NGX_THREADS)
rev[i].lock = &c[i].lock;
rev[i].own_lock = &c[i].lock;
#endif
}
cycle->write_events = ngx_alloc(sizeof(ngx_event_t) * cycle->connection_n,
cycle->log);
if (cycle->write_events == NULL) {
return NGX_ERROR;
}
wev = cycle->write_events;
for (i = 0; i < cycle->connection_n; i++) {
wev[i].closed = 1;
#if (NGX_THREADS)
wev[i].lock = &c[i].lock;
wev[i].own_lock = &c[i].lock;
#endif
}
i = cycle->connection_n;
next = NULL;
do {
i--;
c[i].data = next;
c[i].read = &cycle->read_events[i];
c[i].write = &cycle->write_events[i];
c[i].fd = (ngx_socket_t) -1;
next = &c[i];
#if (NGX_THREADS)
c[i].lock = 0;
#endif
} while (i);
cycle->free_connections = next;
cycle->free_connection_n = cycle->connection_n;
/* for each listening socket */
ls = cycle->listening.elts;
for (i = 0; i < cycle->listening.nelts; i++) {
c = ngx_get_connection(ls[i].fd, cycle->log);
if (c == NULL) {
return NGX_ERROR;
}
c->log = &ls[i].log;
c->listening = &ls[i];
ls[i].connection = c;
rev = c->read;
rev->log = c->log;
rev->accept = 1;
#if (NGX_HAVE_DEFERRED_ACCEPT)
rev->deferred_accept = ls[i].deferred_accept;
#endif
if (!(ngx_event_flags & NGX_USE_IOCP_EVENT)) {
if (ls[i].previous) {
/*
* delete the old accept events that were bound to
* the old cycle read events array
*/
old = ls[i].previous->connection;
if (ngx_del_event(old->read, NGX_READ_EVENT, NGX_CLOSE_EVENT)
== NGX_ERROR)
{
return NGX_ERROR;
}
old->fd = (ngx_socket_t) -1;
}
}
#if (NGX_WIN32)
if (ngx_event_flags & NGX_USE_IOCP_EVENT) {
ngx_iocp_conf_t *iocpcf;
rev->handler = ngx_event_acceptex;
if (ngx_use_accept_mutex) {
continue;
}
if (ngx_add_event(rev, 0, NGX_IOCP_ACCEPT) == NGX_ERROR) {
return NGX_ERROR;
}
ls[i].log.handler = ngx_acceptex_log_error;
iocpcf = ngx_event_get_conf(cycle->conf_ctx, ngx_iocp_module);
if (ngx_event_post_acceptex(&ls[i], iocpcf->post_acceptex)
== NGX_ERROR)
{
return NGX_ERROR;
}
} else {
rev->handler = ngx_event_accept;
if (ngx_use_accept_mutex) {
continue;
}
if (ngx_add_event(rev, NGX_READ_EVENT, 0) == NGX_ERROR) {
return NGX_ERROR;
}
}
#else
rev->handler = ngx_event_accept;
if (ngx_use_accept_mutex) {
continue;
}
if (ngx_event_flags & NGX_USE_RTSIG_EVENT) {
if (ngx_add_conn(c) == NGX_ERROR) {
return NGX_ERROR;
}
} else {
if (ngx_add_event(rev, NGX_READ_EVENT, 0) == NGX_ERROR) {
return NGX_ERROR;
}
}
#endif
}
return NGX_OK;
}
// fork之后，worker进程初始化时调用，即每个worker里都会执行
// 初始化两个延后处理的事件队列,初始化定时器红黑树
// 发送定时信号，更新时间用
// 初始化cycle里的连接和事件数组
// 设置接受连接的回调函数为ngx_event_accept，可以接受连接
static ngx_int_t
ngx_event_process_init(ngx_cycle_t *cycle)
{
ngx_uint_t m, i;
ngx_event_t *rev, *wev;
ngx_listening_t *ls;
ngx_connection_t *c, *next, *old;
ngx_core_conf_t *ccf;
ngx_event_conf_t *ecf;
ngx_event_module_t *module;
// core模块的配置结构体
ccf = (ngx_core_conf_t *) ngx_get_conf(cycle->conf_ctx, ngx_core_module);
// event_core模块的配置结构体
ecf = ngx_event_get_conf(cycle->conf_ctx, ngx_event_core_module);
// 使用master/worker多进程，使用负载均衡
if (ccf->master && ccf->worker_processes > 1 && ecf->accept_mutex) {
// 设置全局变量
// 使用负载均衡，刚开始未持有锁，设置抢锁的等待时间
ngx_use_accept_mutex = 1;
ngx_accept_mutex_held = 0;
ngx_accept_mutex_delay = ecf->accept_mutex_delay;
} else {
// 单进程、未明确指定负载均衡，就不使用负载均衡
ngx_use_accept_mutex = 0;
}
#if (NGX_WIN32)
/*
* disable accept mutex on win32 as it may cause deadlock if
* grabbed by a process which can't accept connections
*/
ngx_use_accept_mutex = 0;
#endif
// 初始化两个延后处理的事件队列
ngx_queue_init(&ngx_posted_accept_events);
ngx_queue_init(&ngx_posted_events);
// 初始化定时器红黑树
if (ngx_event_timer_init(cycle->log) == NGX_ERROR) {
return NGX_ERROR;
}
// 遍历事件模块，但只执行实际使用的事件模块对应初始化函数
for (m = 0; cycle->modules[m]; m++) {
if (cycle->modules[m]->type != NGX_EVENT_MODULE) {
continue;
}
// 找到use指令使用的事件模型，或者是默认事件模型
if (cycle->modules[m]->ctx_index != ecf->use) {
continue;
}
module = cycle->modules[m]->ctx;
// 调用事件模块的事件初始化函数
//
// 调用epoll_create初始化epoll机制
// 参数size=cycle->connection_n / 2，但并无实际意义
// 设置全局变量，操作系统提供的底层数据收发接口
// 初始化全局的事件模块访问接口，指向epoll的函数
// 默认使用et模式，边缘触发，高速
if (module->actions.init(cycle, ngx_timer_resolution) != NGX_OK) {
/* fatal */
exit(2);
}
break;
}
// unix代码, 发送定时信号，更新时间用
#if !(NGX_WIN32)
// NGX_USE_TIMER_EVENT标志量只有eventport/kqueue,epoll无此标志位
// ngx_timer_resolution = ccf->timer_resolution;默认值是0
// 所以只有使用了timer_resolution指令才会发信号
if (ngx_timer_resolution && !(ngx_event_flags & NGX_USE_TIMER_EVENT)) {
struct sigaction sa;
struct itimerval itv;
// 设置信号掩码，sigalarm
ngx_memzero(&sa, sizeof(struct sigaction));
sa.sa_handler = ngx_timer_signal_handler;
sigemptyset(&sa.sa_mask);
if (sigaction(SIGALRM, &sa, NULL) == -1) {
ngx_log_error(NGX_LOG_ALERT, cycle->log, ngx_errno,
"sigaction(SIGALRM) failed");
return NGX_ERROR;
}
// 设置信号发送的时间间隔，也就是nginx的时间精度
// 收到信号会设置设置ngx_event_timer_alarm变量
// 在epoll的ngx_epoll_process_events里检查，更新时间的标志
itv.it_interval.tv_sec = ngx_timer_resolution / 1000;
itv.it_interval.tv_usec = (ngx_timer_resolution % 1000) * 1000;
itv.it_value.tv_sec = ngx_timer_resolution / 1000;
itv.it_value.tv_usec = (ngx_timer_resolution % 1000 ) * 1000;
if (setitimer(ITIMER_REAL, &itv, NULL) == -1) {
ngx_log_error(NGX_LOG_ALERT, cycle->log, ngx_errno,
"setitimer() failed");
}
}
if (ngx_event_flags & NGX_USE_FD_EVENT) {
struct rlimit rlmt;
if (getrlimit(RLIMIT_NOFILE, &rlmt) == -1) {
ngx_log_error(NGX_LOG_ALERT, cycle->log, ngx_errno,
"getrlimit(RLIMIT_NOFILE) failed");
return NGX_ERROR;
}
cycle->files_n = (ngx_uint_t) rlmt.rlim_cur;
cycle->files = ngx_calloc(sizeof(ngx_connection_t *) * cycle->files_n,
cycle->log);
if (cycle->files == NULL) {
return NGX_ERROR;
}
}
#else
if (ngx_timer_resolution && !(ngx_event_flags & NGX_USE_TIMER_EVENT)) {
ngx_log_error(NGX_LOG_WARN, cycle->log, 0,
"the \"timer_resolution\" directive is not supported "
"with the configured event method, ignored");
ngx_timer_resolution = 0;
}
#endif
// 创建连接池数组，大小是cycle->connection_n
// 直接使用malloc分配内存，没有使用内存池
cycle->connections =
ngx_alloc(sizeof(ngx_connection_t) * cycle->connection_n, cycle->log);
if (cycle->connections == NULL) {
return NGX_ERROR;
}
c = cycle->connections;
// 创建读事件池数组，大小是cycle->connection_n
cycle->read_events = ngx_alloc(sizeof(ngx_event_t) * cycle->connection_n,
cycle->log);
if (cycle->read_events == NULL) {
return NGX_ERROR;
}
// 读事件对象初始化
rev = cycle->read_events;
for (i = 0; i < cycle->connection_n; i++) {
rev[i].closed = 1;
rev[i].instance = 1;
}
// 创建写事件池数组，大小是cycle->connection_n
cycle->write_events = ngx_alloc(sizeof(ngx_event_t) * cycle->connection_n,
cycle->log);
if (cycle->write_events == NULL) {
return NGX_ERROR;
}
// 写事件对象初始化
wev = cycle->write_events;
for (i = 0; i < cycle->connection_n; i++) {
wev[i].closed = 1;
}
// i是数组的末尾
i = cycle->connection_n;
next = NULL;
// 把连接对象与读写事件关联起来
// 注意i是数组的末尾，从最后遍历
do {
i--;
// 使用data成员，把连接对象串成链表
c[i].data = next;
// 读写事件
c[i].read = &cycle->read_events[i];
c[i].write = &cycle->write_events[i];
// 连接的描述符是-1，表示无效
c[i].fd = (ngx_socket_t) -1;
// next指针指向数组的前一个元素
next = &c[i];
} while (i);
// 连接对象已经串成链表，现在设置空闲链表指针
// 此时next指向连接对象数组的第一个元素
cycle->free_connections = next;
// 连接没有使用，全是空闲连接
cycle->free_connection_n = cycle->connection_n;
/* for each listening socket */
// 为每个监听端口分配一个连接对象
ls = cycle->listening.elts;
for (i = 0; i < cycle->listening.nelts; i++) {
#if (NGX_HAVE_REUSEPORT)
if (ls[i].reuseport && ls[i].worker != ngx_worker) {
continue;
}
#endif
// 获取一个空闲连接
c = ngx_get_connection(ls[i].fd, cycle->log);
if (c == NULL) {
return NGX_ERROR;
}
c->type = ls[i].type;
c->log = &ls[i].log;
c->listening = &ls[i];
ls[i].connection = c;
rev = c->read;
rev->log = c->log;
// 设置accept标志，接受连接
rev->accept = 1;
#if (NGX_HAVE_DEFERRED_ACCEPT)
rev->deferred_accept = ls[i].deferred_accept;
#endif
if (!(ngx_event_flags & NGX_USE_IOCP_EVENT)) {
if (ls[i].previous) {
/*
* delete the old accept events that were bound to
* the old cycle read events array
*/
old = ls[i].previous->connection;
if (ngx_del_event(old->read, NGX_READ_EVENT, NGX_CLOSE_EVENT)
== NGX_ERROR)
{
return NGX_ERROR;
}
old->fd = (ngx_socket_t) -1;
}
}
#if (NGX_WIN32)
if (ngx_event_flags & NGX_USE_IOCP_EVENT) {
ngx_iocp_conf_t *iocpcf;
rev->handler = ngx_event_acceptex;
if (ngx_use_accept_mutex) {
continue;
}
if (ngx_add_event(rev, 0, NGX_IOCP_ACCEPT) == NGX_ERROR) {
return NGX_ERROR;
}
ls[i].log.handler = ngx_acceptex_log_error;
iocpcf = ngx_event_get_conf(cycle->conf_ctx, ngx_iocp_module);
if (ngx_event_post_acceptex(&ls[i], iocpcf->post_acceptex)
== NGX_ERROR)
{
return NGX_ERROR;
}
} else {
rev->handler = ngx_event_accept;
if (ngx_use_accept_mutex) {
continue;
}
if (ngx_add_event(rev, NGX_READ_EVENT, 0) == NGX_ERROR) {
return NGX_ERROR;
}
}
#else
// 重要！！
// 设置接受连接的回调函数为ngx_event_accept
// 监听端口上收到连接请求时的回调函数，即事件handler
// 从cycle的连接池里获取连接
// 关键操作 ls->handler(c);调用其他模块的业务handler
// 1.10使用ngx_event_recvmsg接收udp
rev->handler = (c->type == SOCK_STREAM) ? ngx_event_accept
: ngx_event_recvmsg;
// 如果使用负载均衡，不向epoll添加事件，只有抢到锁才添加
if (ngx_use_accept_mutex
#if (NGX_HAVE_REUSEPORT)
&& !ls[i].reuseport
#endif
)
{
// 对一个监听端口的处理结束，只设置了回调函数
continue;
}
// nginx 1.9.x不再使用rtsig
// 单进程、未明确指定负载均衡，不使用负载均衡
// 直接加入epoll事件，开始监听，可以接受请求
if (ngx_add_event(rev, NGX_READ_EVENT, 0) == NGX_ERROR) {
return NGX_ERROR;
}
#endif
} // 为每个监听端口分配一个连接对象循环结束
return NGX_OK;
}
static ngx_int_t
ngx_event_process_init(ngx_cycle_t *cycle)
{
ngx_uint_t m, i;
ngx_event_t *rev, *wev;
ngx_listening_t *ls;
ngx_connection_t *c, *next, *old;
ngx_core_conf_t *ccf;
ngx_event_conf_t *ecf;
ngx_event_module_t *module;
ccf = (ngx_core_conf_t *) ngx_get_conf(cycle->conf_ctx, ngx_core_module);
ecf = ngx_event_get_conf(cycle->conf_ctx, ngx_event_core_module);
/* [analy] ngx_use_accept_mutex表示是否需要通过对accept加锁来解决惊群问题。
当nginx worker进程数>1时且配置文件中打开accept_mutex时，这个标志置为1
*/
if (ccf->master && ccf->worker_processes > 1 && ecf->accept_mutex) {
ngx_use_accept_mutex = 1;
ngx_accept_mutex_held = 0;
ngx_accept_mutex_delay = ecf->accept_mutex_delay;
} else {
ngx_use_accept_mutex = 0;
}
#if (NGX_THREADS)
ngx_posted_events_mutex = ngx_mutex_init(cycle->log, 0);
if (ngx_posted_events_mutex == NULL) {
return NGX_ERROR;
}
#endif
/* [analy] ??????????? */
if (ngx_event_timer_init(cycle->log) == NGX_ERROR) {
return NGX_ERROR;
}
/* [analy] 调用事件处理模块(epoll)初始化函数 */
for (m = 0; ngx_modules[m]; m++) {
if (ngx_modules[m]->type != NGX_EVENT_MODULE) {
continue;
}
if (ngx_modules[m]->ctx_index != ecf->use) {
continue;
}
/* [analy]
由于Nginx实现了很多的事件模块，比如：epoll，poll，select, kqueue,aio
（这些模块位于src/event/modules目录中）等等，所以Nginx对事件模块进行
了一层抽象，方便在不同的系统上使用不同的事件模型，也便于扩展新的事件
模型
此处的init回调，其实就是调用了ngx_epoll_init函数。module->actions结构
封装了epoll的所有接口函数。Nginx就是通过actions结构将epoll注册到事件
抽象层中。actions的类型是ngx_event_actions_t
*/
module = ngx_modules[m]->ctx;
if (module->actions.init(cycle, ngx_timer_resolution) != NGX_OK) {
/* fatal */
exit(2);
}
break;
}
#if !(NGX_WIN32)
/*
* timer_resolution指令指定了时间，并且未指定NGX_USE_TIMER_EVENT标记时，
* 根据 timer_resolution 指令指定的时间设置一个定时器
*/
if (ngx_timer_resolution && !(ngx_event_flags & NGX_USE_TIMER_EVENT)) {
struct sigaction sa;
struct itimerval itv;
ngx_memzero(&sa, sizeof(struct sigaction));
sa.sa_handler = ngx_timer_signal_handler;
sigemptyset(&sa.sa_mask);
if (sigaction(SIGALRM, &sa, NULL) == -1) {
ngx_log_error(NGX_LOG_ALERT, cycle->log, ngx_errno,
"sigaction(SIGALRM) failed");
return NGX_ERROR;
}
itv.it_interval.tv_sec = ngx_timer_resolution / 1000;
itv.it_interval.tv_usec = (ngx_timer_resolution % 1000) * 1000;
itv.it_value.tv_sec = ngx_timer_resolution / 1000;
itv.it_value.tv_usec = (ngx_timer_resolution % 1000 ) * 1000;
if (setitimer(ITIMER_REAL, &itv, NULL) == -1) {
ngx_log_error(NGX_LOG_ALERT, cycle->log, ngx_errno,
"setitimer() failed");
}
}
if (ngx_event_flags & NGX_USE_FD_EVENT) { /* [analy] epoll模块不使用 */
struct rlimit rlmt;
if (getrlimit(RLIMIT_NOFILE, &rlmt) == -1) {
ngx_log_error(NGX_LOG_ALERT, cycle->log, ngx_errno,
"getrlimit(RLIMIT_NOFILE) failed");
return NGX_ERROR;
}
cycle->files_n = (ngx_uint_t) rlmt.rlim_cur;
cycle->files = ngx_calloc(sizeof(ngx_connection_t *) * cycle->files_n,
cycle->log);
if (cycle->files == NULL) {
return NGX_ERROR;
}
}
#endif
/* [analy] 为连接池申请空间，由于此处在worker进程初始化时进行的，所以
每个worker都会拥有一个自己的connections连接池
根据配置worker_connections指令指定的个数申请 */
cycle->connections =
ngx_alloc(sizeof(ngx_connection_t) * cycle->connection_n, cycle->log);
if (cycle->connections == NULL) {
return NGX_ERROR;
}
c = cycle->connections;
/* [analy] 为读事件队列申请空间 */
cycle->read_events = ngx_alloc(sizeof(ngx_event_t) * cycle->connection_n,
cycle->log);
if (cycle->read_events == NULL) {
return NGX_ERROR;
}
rev = cycle->read_events;
for (i = 0; i < cycle->connection_n; i++) {
rev[i].closed = 1;
rev[i].instance = 1;
#if (NGX_THREADS)
rev[i].lock = &c[i].lock;
rev[i].own_lock = &c[i].lock;
#endif
}
/* [analy] 为写事件队列申请空间 */
cycle->write_events = ngx_alloc(sizeof(ngx_event_t) * cycle->connection_n,
cycle->log);
if (cycle->write_events == NULL) {
return NGX_ERROR;
}
wev = cycle->write_events;
for (i = 0; i < cycle->connection_n; i++) {
wev[i].closed = 1;
#if (NGX_THREADS)
wev[i].lock = &c[i].lock;
wev[i].own_lock = &c[i].lock;
#endif
}
/* [analy] 初始化connections数组
data字段指向下一个元素
read事件指针指向read_events对应下标的元素
write事件指针指向write_events对应下标的元素
fd初始化-1
*/
i = cycle->connection_n;
next = NULL;
do {
i--;
c[i].data = next;
c[i].read = &cycle->read_events[i]; /* [analy] 将连接池中connections的read事件与read_events数组中的对应下标的元素关联 */
c[i].write = &cycle->write_events[i]; /* [analy] 将连接池中connections的write事件与write_events数组中对应下标元素关联 */
c[i].fd = (ngx_socket_t) -1;
next = &c[i];
#if (NGX_THREADS)
c[i].lock = 0;
#endif
} while (i);
/* 初始化free_connections空闲连接池和空闲连接个数;指向connections连接池首地址 */
cycle->free_connections = next;
cycle->free_connection_n = cycle->connection_n;
/* [analy] 为每一个套接口分配一个空闲的连接 */
/* for each listening socket */
ls = cycle->listening.elts;
for (i = 0; i < cycle->listening.nelts; i++) {
c = ngx_get_connection(ls[i].fd, cycle->log);
if (c == NULL) {
return NGX_ERROR;
}
c->log = &ls[i].log;
c->listening = &ls[i]; /* [analy] connection的listening指针指向cycle->listening[n] */
ls[i].connection = c; /* [analy] cycle->listening[n]->connection指针指向了申请的空闲connection */
rev = c->read;
rev->log = c->log;
rev->accept = 1; // 设置监听套接字标识
#if (NGX_HAVE_DEFERRED_ACCEPT)
rev->deferred_accept = ls[i].deferred_accept;
#endif
if (!(ngx_event_flags & NGX_USE_IOCP_EVENT)) {
if (ls[i].previous) {
/*
* delete the old accept events that were bound to
* the old cycle read events array
*/
old = ls[i].previous->connection;
if (ngx_del_event(old->read, NGX_READ_EVENT, NGX_CLOSE_EVENT)
== NGX_ERROR)
{
return NGX_ERROR;
}
old->fd = (ngx_socket_t) -1;
}
}
#if (NGX_WIN32)
if (ngx_event_flags & NGX_USE_IOCP_EVENT) {
ngx_iocp_conf_t *iocpcf;
rev->handler = ngx_event_acceptex;
if (ngx_use_accept_mutex) {
continue;
}
if (ngx_add_event(rev, 0, NGX_IOCP_ACCEPT) == NGX_ERROR) {
return NGX_ERROR;
}
ls[i].log.handler = ngx_acceptex_log_error;
iocpcf = ngx_event_get_conf(cycle->conf_ctx, ngx_iocp_module);
if (ngx_event_post_acceptex(&ls[i], iocpcf->post_acceptex)
== NGX_ERROR)
{
return NGX_ERROR;
}
} else {
rev->handler = ngx_event_accept;
if (ngx_use_accept_mutex) {
continue;
}
if (ngx_add_event(rev, NGX_READ_EVENT, 0) == NGX_ERROR) {
return NGX_ERROR;
}
}
#else
rev->handler = ngx_event_accept; /* [analy] 设置accpet回调处理函数 */
if (ngx_use_accept_mutex) {
continue;
}
if (ngx_event_flags & NGX_USE_RTSIG_EVENT) {
if (ngx_add_conn(c) == NGX_ERROR) {
return NGX_ERROR;
}
} else {
if (ngx_add_event(rev, NGX_READ_EVENT, 0) == NGX_ERROR) { /* [analy] 将event送进epoll队列中 */
return NGX_ERROR;
}
}
#endif
}
return NGX_OK;
}
static ngx_int_t ngx_event_process_init(ngx_cycle_t *cycle)
{
ngx_uint_t m, i;
ngx_socket_t fd;
ngx_event_t *rev, *wev;
ngx_listening_t *s;
ngx_connection_t *c;
ngx_core_conf_t *ccf;
ngx_event_conf_t *ecf;
ngx_event_module_t *module;
#if (WIN32)
ngx_iocp_conf_t *iocpcf;
#endif
ccf = (ngx_core_conf_t *) ngx_get_conf(cycle->conf_ctx, ngx_core_module);
ecf = ngx_event_get_conf(cycle->conf_ctx, ngx_event_core_module);
// 如果accept时需要锁, 那么初始化锁
if (ngx_accept_mutex_ptr && ccf->worker_processes > 1 && ecf->accept_mutex)
{
ngx_accept_mutex = ngx_accept_mutex_ptr;
ngx_accept_mutex_held = 0;
ngx_accept_mutex_delay = ecf->accept_mutex_delay;
}
#if (NGX_THREADS)
if (!(ngx_posted_events_mutex = ngx_mutex_init(cycle->log, 0))) {
return NGX_ERROR;
}
#endif
// 初始化定时器
if (ngx_event_timer_init(cycle->log) == NGX_ERROR) {
return NGX_ERROR;
}
cycle->connection_n = ecf->connections;
for (m = 0; ngx_modules[m]; m++) {
if (ngx_modules[m]->type != NGX_EVENT_MODULE) {
continue;
}
// 初始化选定的事件模块
if (ngx_modules[m]->ctx_index == ecf->use) {
module = ngx_modules[m]->ctx;
if (module->actions.init(cycle) == NGX_ERROR) {
/* fatal */
exit(2);
}
break;
}
}
// 根据连接最大数来创建连接对象池
cycle->connections = ngx_alloc(sizeof(ngx_connection_t) * ecf->connections,
cycle->log);
if (cycle->connections == NULL) {
return NGX_ERROR;
}
// 初始化连接池
c = cycle->connections;
for (i = 0; i < cycle->connection_n; i++) {
c[i].fd = (ngx_socket_t) -1;
c[i].data = NULL;
#if (NGX_THREADS)
c[i].lock = 0;
#endif
}
// 初始化事件相关的对象
cycle->read_events = ngx_alloc(sizeof(ngx_event_t) * ecf->connections,
cycle->log);
if (cycle->read_events == NULL) {
return NGX_ERROR;
}
rev = cycle->read_events;
for (i = 0; i < cycle->connection_n; i++) {
rev[i].closed = 1;
#if (NGX_THREADS)
rev[i].lock = &c[i].lock;
rev[i].own_lock = &c[i].lock;
#endif
}
cycle->write_events = ngx_alloc(sizeof(ngx_event_t) * ecf->connections,
cycle->log);
if (cycle->write_events == NULL) {
return NGX_ERROR;
}
wev = cycle->write_events;
for (i = 0; i < cycle->connection_n; i++) {
wev[i].closed = 1;
#if (NGX_THREADS)
wev[i].lock = &c[i].lock;
wev[i].own_lock = &c[i].lock;
#endif
}
/* for each listening socket */
// 用事件对象与监听的socket相关联
s = cycle->listening.elts;
for (i = 0; i < cycle->listening.nelts; i++) {
fd = s[i].fd;
#if (WIN32)
/*
* Winsock assignes a socket number divisible by 4
* so to find a connection we divide a socket number by 4.
*/
fd /= 4;
#endif
c = &cycle->connections[fd];
rev = &cycle->read_events[fd];
wev = &cycle->write_events[fd];
ngx_memzero(c, sizeof(ngx_connection_t));
ngx_memzero(rev, sizeof(ngx_event_t));
c->fd = s[i].fd;
c->listening = &s[i];
c->ctx = s[i].ctx;
c->servers = s[i].servers;
c->log = s[i].log;
c->read = rev;
/* required by iocp in "c->write->active = 1" */
c->write = wev;
/* required by poll */
wev->index = NGX_INVALID_INDEX;
rev->log = c->log;
rev->data = c;
rev->index = NGX_INVALID_INDEX;
rev->available = 0;
rev->accept = 1;
#if (HAVE_DEFERRED_ACCEPT)
rev->deferred_accept = s[i].deferred_accept;
#endif
if (!(ngx_event_flags & NGX_USE_IOCP_EVENT)) {
if (s[i].remain) {
/*
* delete the old accept events that were bound to
* the old cycle read events array
*/
if (ngx_del_event(&cycle->old_cycle->read_events[fd],
NGX_READ_EVENT, NGX_CLOSE_EVENT) == NGX_ERROR)
{
return NGX_ERROR;
}
cycle->old_cycle->connections[fd].fd = (ngx_socket_t) -1;
}
}
#if (WIN32)
if (ngx_event_flags & NGX_USE_IOCP_EVENT) {
rev->event_handler = &ngx_event_acceptex;
if (ngx_add_event(rev, 0, NGX_IOCP_ACCEPT) == NGX_ERROR) {
return NGX_ERROR;
}
iocpcf = ngx_event_get_conf(cycle->conf_ctx, ngx_iocp_module);
if (ngx_event_post_acceptex(&s[i], iocpcf->post_acceptex)
== NGX_ERROR)
{
return NGX_ERROR;
}
} else {
rev->event_handler = &ngx_event_accept;
if (ngx_add_event(rev, NGX_READ_EVENT, 0) == NGX_ERROR) {
return NGX_ERROR;
}
}
#else
rev->event_handler = &ngx_event_accept; // 读事件的回调函数
// 如果需要accept锁, 那么延迟添加到事件池中
if (ngx_accept_mutex) {
continue;
}
if (ngx_event_flags & NGX_USE_RTSIG_EVENT) {
if (ngx_add_conn(c) == NGX_ERROR) {
return NGX_ERROR;
}
} else {
if (ngx_add_event(rev, NGX_READ_EVENT, 0) == NGX_ERROR) {
return NGX_ERROR;
}
}
#endif
}
return NGX_OK;
}
// 这篇文章写得很清晰http://www.tbdata.org/archives/1245
static ngx_int_t
ngx_event_process_init(ngx_cycle_t *cycle)
{
ngx_uint_t m, i;
ngx_event_t *rev, *wev;
ngx_listening_t *ls;
ngx_connection_t *c, *next, *old;
ngx_core_conf_t *ccf;
ngx_event_conf_t *ecf;
ngx_event_module_t *module;
// 获取相应模块的配置结构
ccf = (ngx_core_conf_t *) ngx_get_conf(cycle->conf_ctx, ngx_core_module);
ecf = ngx_event_get_conf(cycle->conf_ctx, ngx_event_core_module);
// 判断是否使用mutex锁，主要是为了控制负载均衡。ccf->master主要确定下是否是master-worker模式。单进程模式就不需要进行下面操作了。
if (ccf->master && ccf->worker_processes > 1 && ecf->accept_mutex) {
//使用mutex控制进程的负载均衡
ngx_use_accept_mutex = 1;
ngx_accept_mutex_held = 0;
ngx_accept_mutex_delay = ecf->accept_mutex_delay; // 抢互斥体失败后，下次再抢的间隔时间
} else {
ngx_use_accept_mutex = 0;
}
#if (NGX_THREADS)
ngx_posted_events_mutex = ngx_mutex_init(cycle->log, 0);
if (ngx_posted_events_mutex == NULL) {
return NGX_ERROR;
}
#endif
//定时器初始化
if (ngx_event_timer_init(cycle->log) == NGX_ERROR) {
return NGX_ERROR;
}
//event module的初始化
for (m = 0; ngx_modules[m]; m++) {
if (ngx_modules[m]->type != NGX_EVENT_MODULE) {
continue;
}
if (ngx_modules[m]->ctx_index != ecf->use) {
continue;
}
module = ngx_modules[m]->ctx;
//初始化模块
if (module->actions.init(cycle, ngx_timer_resolution) != NGX_OK) {
/* fatal */
exit(2);
}
break;
}
#if !(NGX_WIN32)
if (ngx_timer_resolution && !(ngx_event_flags & NGX_USE_TIMER_EVENT)) {
struct sigaction sa;
struct itimerval itv;
ngx_memzero(&sa, sizeof(struct sigaction));
sa.sa_handler = ngx_timer_signal_handler;
sigemptyset(&sa.sa_mask);
if (sigaction(SIGALRM, &sa, NULL) == -1) {
ngx_log_error(NGX_LOG_ALERT, cycle->log, ngx_errno,
"sigaction(SIGALRM) failed");
return NGX_ERROR;
}
itv.it_interval.tv_sec = ngx_timer_resolution / 1000;
itv.it_interval.tv_usec = (ngx_timer_resolution % 1000) * 1000;
itv.it_value.tv_sec = ngx_timer_resolution / 1000;
itv.it_value.tv_usec = (ngx_timer_resolution % 1000 ) * 1000;
if (setitimer(ITIMER_REAL, &itv, NULL) == -1) {
ngx_log_error(NGX_LOG_ALERT, cycle->log, ngx_errno,
"setitimer() failed");
}
}
if (ngx_event_flags & NGX_USE_FD_EVENT) {
struct rlimit rlmt;
if (getrlimit(RLIMIT_NOFILE, &rlmt) == -1) {
ngx_log_error(NGX_LOG_ALERT, cycle->log, ngx_errno,
"getrlimit(RLIMIT_NOFILE) failed");
return NGX_ERROR;
}
cycle->files_n = (ngx_uint_t) rlmt.rlim_cur;
cycle->files = ngx_calloc(sizeof(ngx_connection_t *) * cycle->files_n,
cycle->log);
if (cycle->files == NULL) {
return NGX_ERROR;
}
}
#endif
//创建连接池。现在已经是在worker中了，所以每个worker都有自己的connection数组
cycle->connections =
ngx_alloc(sizeof(ngx_connection_t) * cycle->connection_n, cycle->log);
if (cycle->connections == NULL) {
return NGX_ERROR;
}
c = cycle->connections;
//创建所有读事件
cycle->read_events = ngx_alloc(sizeof(ngx_event_t) * cycle->connection_n,
cycle->log);
if (cycle->read_events == NULL) {
return NGX_ERROR;
}
rev = cycle->read_events;
//初始化读事件
for (i = 0; i < cycle->connection_n; i++) {
rev[i].closed = 1;
//防止stale event
rev[i].instance = 1;
#if (NGX_THREADS)
rev[i].lock = &c[i].lock;
rev[i].own_lock = &c[i].lock;
#endif
}
//创建写事件
cycle->write_events = ngx_alloc(sizeof(ngx_event_t) * cycle->connection_n,
cycle->log);
if (cycle->write_events == NULL) {
return NGX_ERROR;
}
wev = cycle->write_events;
//初始化写事件
for (i = 0; i < cycle->connection_n; i++) {
wev[i].closed = 1;
#if (NGX_THREADS)
wev[i].lock = &c[i].lock;
wev[i].own_lock = &c[i].lock;
#endif
}
i = cycle->connection_n;
next = NULL;
//初始化连接池
do {
i--;
//链表
c[i].data = next;
//每一个连接的读写事件对应cycle的读写事件
c[i].read = &cycle->read_events[i];
c[i].write = &cycle->write_events[i];
c[i].fd = (ngx_socket_t) -1;
next = &c[i];
#if (NGX_THREADS)
c[i].lock = 0;
#endif
} while (i);
//设置free 连接
cycle->free_connections = next;
cycle->free_connection_n = cycle->connection_n;
/* for each listening socket */
//下面这段初始化listen 事件 ，创建socket句柄，绑定事件回调，然后加入到事件驱动中
ls = cycle->listening.elts; // 为每一个监听套接字从connection数组中分配一个连接，即一个slot
//开始遍历listen
for (i = 0; i < cycle->listening.nelts; i++) {
//从连接池取得连接
c = ngx_get_connection(ls[i].fd, cycle->log);
if (c == NULL) {
return NGX_ERROR;
}
c->log = &ls[i].log;
c->listening = &ls[i];
ls[i].connection = c;
rev = c->read;
rev->log = c->log;
rev->accept = 1;
#if (NGX_HAVE_DEFERRED_ACCEPT)
rev->deferred_accept = ls[i].deferred_accept;
#endif
if (!(ngx_event_flags & NGX_USE_IOCP_EVENT)) {
if (ls[i].previous) {
/*
* delete the old accept events that were bound to
* the old cycle read events array
*/
old = ls[i].previous->connection;
if (ngx_del_event(old->read, NGX_READ_EVENT, NGX_CLOSE_EVENT)
== NGX_ERROR)
{
return NGX_ERROR;
}
old->fd = (ngx_socket_t) -1;
}
}
#if (NGX_WIN32)
if (ngx_event_flags & NGX_USE_IOCP_EVENT) {
ngx_iocp_conf_t *iocpcf;
rev->handler = ngx_event_acceptex;
if (ngx_use_accept_mutex) {
continue;
}
if (ngx_add_event(rev, 0, NGX_IOCP_ACCEPT) == NGX_ERROR) {
return NGX_ERROR;
}
ls[i].log.handler = ngx_acceptex_log_error;
iocpcf = ngx_event_get_conf(cycle->conf_ctx, ngx_iocp_module);
if (ngx_event_post_acceptex(&ls[i], iocpcf->post_acceptex)
== NGX_ERROR)
{
return NGX_ERROR;
}
} else {
rev->handler = ngx_event_accept; // 注册监听套接读事件的回调函数ngx_event_accept
if (ngx_use_accept_mutex) {
continue;
}
if (ngx_add_event(rev, NGX_READ_EVENT, 0) == NGX_ERROR) {
return NGX_ERROR;
}
}
#else
//设置listen句柄的事件回调，这个回调里面会accept，然后进行后续处理，这个函数是nginx事件驱动的第一个函数
rev->handler = ngx_event_accept;
//如果默认使用mutex，则会继续下面操作
if (ngx_use_accept_mutex) {
continue;
}
if (ngx_event_flags & NGX_USE_RTSIG_EVENT) {
if (ngx_add_conn(c) == NGX_ERROR) {
return NGX_ERROR;
}
} else {
//加可读事件到事件处理，如果没有使用accept互斥体，那么就在此处将监听套接字放入
if (ngx_add_event(rev, NGX_READ_EVENT, 0) == NGX_ERROR) {
return NGX_ERROR;
}
}
#endif
}
return NGX_OK;
}
//Here,This function very important!
static ngx_int_t ngx_event_process_init(ngx_cycle_t *cycle)
{
ngx_uint_t m, i;
ngx_event_t *rev, *wev;
ngx_listening_t *ls;
ngx_connection_t *c, *next, *old;
ngx_core_conf_t *ccf;
ngx_event_conf_t *ecf;
ngx_event_module_t *module;
ccf = (ngx_core_conf_t *) ngx_get_conf(cycle->conf_ctx, ngx_core_module);
ecf = ngx_event_get_conf(cycle->conf_ctx, ngx_event_core_module);
if (ccf->master && ccf->worker_processes > 1 && ecf->accept_mutex) {
ngx_use_accept_mutex = 1; //Means we used a multi worker!!!!
ngx_accept_mutex_held = 0;
ngx_accept_mutex_delay = ecf->accept_mutex_delay;
} else {
ngx_use_accept_mutex = 0;
}
#if (NGX_THREADS)
ngx_posted_events_mutex = ngx_mutex_init(cycle->log, 0);
if (ngx_posted_events_mutex == NULL) {
return NGX_ERROR;
}
#endif
if (ngx_event_timer_init(cycle->log) == NGX_ERROR) {
return NGX_ERROR;
}
for (m = 0; ngx_modules[m]; m++) {
if (ngx_modules[m]->type != NGX_EVENT_MODULE) {
continue;
}
if (ngx_modules[m]->ctx_index != ecf->use) {//Here,find the used event scheme!!!!
continue;
}
module = ngx_modules[m]->ctx;
if (module->actions.init(cycle, ngx_timer_resolution) != NGX_OK) {//Here,we set the global ngx_event_actions!!!!!
/* fatal */
exit(2);
}
break;
}
#if !(NGX_WIN32)
if (ngx_timer_resolution && !(ngx_event_flags & NGX_USE_TIMER_EVENT)) {
struct sigaction sa;
struct itimerval itv;
ngx_memzero(&sa, sizeof(struct sigaction));
sa.sa_handler = ngx_timer_signal_handler;
sigemptyset(&sa.sa_mask);
if (sigaction(SIGALRM, &sa, NULL) == -1) {
ngx_log_error(NGX_LOG_ALERT, cycle->log, ngx_errno,
"sigaction(SIGALRM) failed");
return NGX_ERROR;
}
itv.it_interval.tv_sec = ngx_timer_resolution / 1000;
itv.it_interval.tv_usec = (ngx_timer_resolution % 1000) * 1000;
itv.it_value.tv_sec = ngx_timer_resolution / 1000;
itv.it_value.tv_usec = (ngx_timer_resolution % 1000 ) * 1000;
if (setitimer(ITIMER_REAL, &itv, NULL) == -1) {
ngx_log_error(NGX_LOG_ALERT, cycle->log, ngx_errno,
"setitimer() failed");
}
}
if (ngx_event_flags & NGX_USE_FD_EVENT) {
struct rlimit rlmt;
if (getrlimit(RLIMIT_NOFILE, &rlmt) == -1) {
ngx_log_error(NGX_LOG_ALERT, cycle->log, ngx_errno,
"getrlimit(RLIMIT_NOFILE) failed");
return NGX_ERROR;
}
cycle->files_n = (ngx_uint_t) rlmt.rlim_cur;
cycle->files = ngx_calloc(sizeof(ngx_connection_t *) * cycle->files_n,
cycle->log);
if (cycle->files == NULL) {
return NGX_ERROR;
}
}
#endif
//Here,we alloction the connection pool!!
cycle->connections = ngx_alloc(sizeof(ngx_connection_t) * cycle->connection_n, cycle->log);
if (cycle->connections == NULL) {
return NGX_ERROR;
}
c = cycle->connections;
//Here,alloction the read_events pool
cycle->read_events = ngx_alloc(sizeof(ngx_event_t) * cycle->connection_n,cycle->log);
if (cycle->read_events == NULL) {
return NGX_ERROR;
}
rev = cycle->read_events;
for (i = 0; i < cycle->connection_n; i++) {
rev[i].closed = 1;
rev[i].instance = 1;
#if (NGX_THREADS)
rev[i].lock = &c[i].lock;
rev[i].own_lock = &c[i].lock;
#endif
}
//Here,alloction the write_events pool
cycle->write_events = ngx_alloc(sizeof(ngx_event_t) * cycle->connection_n,cycle->log);
if (cycle->write_events == NULL) {
return NGX_ERROR;
}
wev = cycle->write_events;
for (i = 0; i < cycle->connection_n; i++) {
wev[i].closed = 1;
#if (NGX_THREADS)
wev[i].lock = &c[i].lock;
wev[i].own_lock = &c[i].lock;
#endif
}
i = cycle->connection_n;
next = NULL;
//Here,make a pair!!! on connection,to one rev and one wev!!!
do {
i--;
c[i].data = next;//point to the next free connection!!!!
c[i].read = &cycle->read_events[i];
c[i].write = &cycle->write_events[i];
c[i].fd = (ngx_socket_t) -1;
next = &c[i];
#if (NGX_THREADS)
c[i].lock = 0;
#endif
} while (i);
cycle->free_connections = next;
cycle->free_connection_n = cycle->connection_n;
/* for each listening socket */
ls = cycle->listening.elts;//
//-------------->very important!!!
//-------------->start to initilize a connection for every listening socket!!!
for (i = 0; i < cycle->listening.nelts; i++) {
c = ngx_get_connection(ls[i].fd, cycle->log);//Get a free connection!
if (c == NULL) {
return NGX_ERROR;
}
c->log = &ls[i].log;
c->listening = &ls[i];//Means this connection bind to this listen socket!!!
ls[i].connection = c;
rev = c->read;
rev->log = c->log;
rev->accept = 1;
//Means mark that this rev use to accept request,It is a special read_event!!!
//This read_event handler should be call be for release the ngx_accept_mutex
#if (NGX_HAVE_DEFERRED_ACCEPT)
rev->deferred_accept = ls[i].deferred_accept;
#endif
if (!(ngx_event_flags & NGX_USE_IOCP_EVENT)) {
if (ls[i].previous) {
/*
* delete the old accept events that were bound to
* the old cycle read events array
*/
old = ls[i].previous->connection;
if (ngx_del_event(old->read, NGX_READ_EVENT, NGX_CLOSE_EVENT) == NGX_ERROR)
{
return NGX_ERROR;
}
old->fd = (ngx_socket_t) -1;
}
}
#if (NGX_WIN32)
if (ngx_event_flags & NGX_USE_IOCP_EVENT) {
ngx_iocp_conf_t *iocpcf;
rev->handler = ngx_event_acceptex;
if (ngx_use_accept_mutex) {
continue;
}
if (ngx_add_event(rev, 0, NGX_IOCP_ACCEPT) == NGX_ERROR) {
return NGX_ERROR;
}
ls[i].log.handler = ngx_acceptex_log_error;
iocpcf = ngx_event_get_conf(cycle->conf_ctx, ngx_iocp_module);
if (ngx_event_post_acceptex(&ls[i], iocpcf->post_acceptex)
== NGX_ERROR)
{
return NGX_ERROR;
}
} else {
rev->handler = ngx_event_accept;
if (ngx_use_accept_mutex) {
continue;
}
if (ngx_add_event(rev, NGX_READ_EVENT, 0) == NGX_ERROR) {
return NGX_ERROR;
}
}
#else
//Here,set the read_handler!!!
rev->handler = ngx_event_accept;
if (ngx_use_accept_mutex) {
continue;
}
if (ngx_event_flags & NGX_USE_RTSIG_EVENT) {
if (ngx_add_conn(c) == NGX_ERROR) {
return NGX_ERROR;
}
} else {
if (ngx_add_event(rev, NGX_READ_EVENT, 0) == NGX_ERROR) {
return NGX_ERROR;
}
}
#endif
}
return NGX_OK;
}
//在创建子进程的里面执行 ngx_worker_process_init
static ngx_int_t
ngx_event_process_init(ngx_cycle_t *cycle)
{
ngx_uint_t m, i;
ngx_event_t *rev, *wev;
ngx_listening_t *ls;
ngx_connection_t *c, *next, *old;
ngx_core_conf_t *ccf;
ngx_event_conf_t *ecf;
ngx_event_module_t *module;
ccf = (ngx_core_conf_t *) ngx_get_conf(cycle->conf_ctx, ngx_core_module);
ecf = ngx_event_get_conf(cycle->conf_ctx, ngx_event_core_module);
/*
当打开accept_mutex负载均衡锁，同时使用了master模式并且worker迸程数量大于1时，才正式确定了进程将使用accept_mutex负载均衡锁。
因此，即使我们在配置文件中指定打开accept_mutex锁，如果没有使用master模式或者worker进程数量等于1，进程在运行时还是不会使用
负载均衡锁（既然不存在多个进程去抢一个监听端口上的连接的情况，那么自然不需要均衡多个worker进程的负载）。
这时会将ngx_use_accept_mutex全局变量置为1，ngx_accept_mutex_held标志设为0，ngx_accept_mutex_delay则设为在配置文件中指定的最大延迟时间。
这3个变量的意义可参见9.8节中关于负载均衡锁的说明。
*/
if (ccf->master && ccf->worker_processes > 1 && ecf->accept_mutex) {
ngx_use_accept_mutex = 1;
ngx_accept_mutex_held = 0;
ngx_accept_mutex_delay = ecf->accept_mutex_delay;
} else {
ngx_use_accept_mutex = 0;
}
#if (NGX_WIN32)
/*
* disable accept mutex on win32 as it may cause deadlock if
* grabbed by a process which can't accept connections
*/
ngx_use_accept_mutex = 0;
#endif
ngx_queue_init(&ngx_posted_accept_events);
ngx_queue_init(&ngx_posted_events);
//初始化红黑树实现的定时器。关于定时器的实现细节可参见9.6节。
if (ngx_event_timer_init(cycle->log) == NGX_ERROR) {
return NGX_ERROR;
}
//在调用use配置项指定的事件模块中，在ngx_event_module_t接口下，ngx_event_actions_t中的init方法进行这个事件模块的初始化工作。
for (m = 0; ngx_modules[m]; m++) {
if (ngx_modules[m]->type != NGX_EVENT_MODULE) {
continue;
}
if (ngx_modules[m]->ctx_index != ecf->use) { //找到epoll或者select的module模块
continue;
}
module = ngx_modules[m]->ctx;
if (module->actions.init(cycle, ngx_timer_resolution) != NGX_OK) { //执行epoll module中的ngx_epoll_init
/* fatal */
exit(2);
}
break; /*跳出循环，只可能使用一个具体的事件模型*/
}
#if !(NGX_WIN32)
/*
如果nginx.conf配置文件中设置了timer_resolution酡置项，即表明需要控制时间精度，这时会调用setitimer方法，设置时间间隔
为timer_resolution毫秒来回调ngx_timer_signal_handler方法
*/
if (ngx_timer_resolution && !(ngx_event_flags & NGX_USE_TIMER_EVENT)) {
struct sigaction sa;
struct itimerval itv;
//设置定时器
/*
在ngx_event_ actions t的process_events方法中，每一个事件驱动模块都需要在ngx_event_timer_alarm为1时调
用ngx_time_update方法（参见9.7.1节）更新系统时间，在更新系统结束后需要将ngx_event_timer_alarm设为0。
*/
ngx_memzero(&sa, sizeof(struct sigaction)); //每隔ngx_timer_resolution ms会超时执行handle
sa.sa_handler = ngx_timer_signal_handler;
sigemptyset(&sa.sa_mask);
if (sigaction(SIGALRM, &sa, NULL) == -1) {
ngx_log_error(NGX_LOG_ALERT, cycle->log, ngx_errno,
"sigaction(SIGALRM) failed");
return NGX_ERROR;
}
itv.it_interval.tv_sec = ngx_timer_resolution / 1000;
itv.it_interval.tv_usec = (ngx_timer_resolution % 1000) * 1000;
itv.it_value.tv_sec = ngx_timer_resolution / 1000;
itv.it_value.tv_usec = (ngx_timer_resolution % 1000 ) * 1000;
if (setitimer(ITIMER_REAL, &itv, NULL) == -1) {
ngx_log_error(NGX_LOG_ALERT, cycle->log, ngx_errno,
"setitimer() failed");
}
}
/*
如果使用了epoll事件驱动模式，那么会为ngx_cycle_t结构体中的files成员预分配旬柄。
*/
if (ngx_event_flags & NGX_USE_FD_EVENT) {
struct rlimit rlmt;
if (getrlimit(RLIMIT_NOFILE, &rlmt) == -1) {
ngx_log_error(NGX_LOG_ALERT, cycle->log, ngx_errno,
"getrlimit(RLIMIT_NOFILE) failed");
return NGX_ERROR;
}
cycle->files_n = (ngx_uint_t) rlmt.rlim_cur; //每个进程能够打开的最多文件数
cycle->files = ngx_calloc(sizeof(ngx_connection_t *) * cycle->files_n,
cycle->log);
if (cycle->files == NULL) {
return NGX_ERROR;
}
}
#endif
cycle->connections =
ngx_alloc(sizeof(ngx_connection_t) * cycle->connection_n, cycle->log);
if (cycle->connections == NULL) {
return NGX_ERROR;
}
c = cycle->connections;
cycle->read_events = ngx_alloc(sizeof(ngx_event_t) * cycle->connection_n,
cycle->log);
if (cycle->read_events == NULL) {
return NGX_ERROR;
}
rev = cycle->read_events;
for (i = 0; i < cycle->connection_n; i++) {
rev[i].closed = 1;
rev[i].instance = 1;
}
cycle->write_events = ngx_alloc(sizeof(ngx_event_t) * cycle->connection_n,
cycle->log);
if (cycle->write_events == NULL) {
return NGX_ERROR;
}
wev = cycle->write_events;
for (i = 0; i < cycle->connection_n; i++) {
wev[i].closed = 1;
}
i = cycle->connection_n;
next = NULL;
/*
接照序号，将上述3个数组相应的读/写事件设置到每一个ngx_connection_t连接对象中，同时把这些连接以ngx_connection_t中的data成员
作为next指针串联成链表，为下一步设置空闲连接链表做好准备
*/
do {
i--;
c[i].data = next;
c[i].read = &cycle->read_events[i];
c[i].write = &cycle->write_events[i];
c[i].fd = (ngx_socket_t) -1;
next = &c[i];
} while (i);
/*
将ngx_cycle_t结构体中的空闲连接链表free_connections指向connections数组的最后1个元素，也就是第10步所有ngx_connection_t连
接通过data成员组成的单链表的首部。
*/
cycle->free_connections = next;
cycle->free_connection_n = cycle->connection_n;
/* for each listening socket */
/*
在刚刚建立好的连接池中，为所有ngx_listening_t监听对象中的connection成员分配连接，同时对监听端口的读事件设置处理方法
为ngx_event_accept，也就是说，有新连接事件时将调用ngx_event_accept方法建立新连接（详见9.8节中关于如何建立新连接的内容）。
*/
ls = cycle->listening.elts;
for (i = 0; i < cycle->listening.nelts; i++) {
#if (NGX_HAVE_REUSEPORT)
if (ls[i].reuseport && ls[i].worker != ngx_worker) {
continue;
}
#endif
c = ngx_get_connection(ls[i].fd, cycle->log); //从连接池中获取一个ngx_connection_t
if (c == NULL) {
return NGX_ERROR;
}
c->log = &ls[i].log;
c->listening = &ls[i]; //把解析到listen配置项信息赋值给ngx_connection_s中的listening中
ls[i].connection = c;
rev = c->read;
rev->log = c->log;
rev->accept = 1;
#if (NGX_HAVE_DEFERRED_ACCEPT)
rev->deferred_accept = ls[i].deferred_accept;
#endif
if (!(ngx_event_flags & NGX_USE_IOCP_EVENT)) {
if (ls[i].previous) {
/*
* delete the old accept events that were bound to
* the old cycle read events array
*/
old = ls[i].previous->connection;
if (ngx_del_event(old->read, NGX_READ_EVENT, NGX_CLOSE_EVENT)
== NGX_ERROR)
{
return NGX_ERROR;
}
old->fd = (ngx_socket_t) -1;
}
}
#if (NGX_WIN32)
if (ngx_event_flags & NGX_USE_IOCP_EVENT) {
ngx_iocp_conf_t *iocpcf;
rev->handler = ngx_event_acceptex;
if (ngx_use_accept_mutex) {
continue;
}
if (ngx_add_event(rev, 0, NGX_IOCP_ACCEPT) == NGX_ERROR) {
return NGX_ERROR;
}
ls[i].log.handler = ngx_acceptex_log_error;
iocpcf = ngx_event_get_conf(cycle->conf_ctx, ngx_iocp_module);
if (ngx_event_post_acceptex(&ls[i], iocpcf->post_acceptex)
== NGX_ERROR)
{
return NGX_ERROR;
}
} else {
rev->handler = ngx_event_accept;
if (ngx_use_accept_mutex) {
continue;
}
if (ngx_add_event(rev, NGX_READ_EVENT, 0) == NGX_ERROR) {
return NGX_ERROR;
}
}
#else
/*
对监听端口的读事件设置处理方法
为ngx_event_accept，也就是说，有新连接事件时将调用ngx_event_accept方法建立新连接（详见9.8节中关于如何建立新连接的内容）。
*/
rev->handler = ngx_event_accept;
/*
使用了accept_mutex，暂时不将监听套接字放入epoll中, 而是等到worker抢到accept互斥体后，再放入epoll，避免惊群的发生。
*/ //在建连接的时候，为了避免惊群，在accept的时候，只有获取到该原子锁，才把accept添加到epoll事件中，见ngx_process_events_and_timers->ngx_trylock_accept_mutex
if (ngx_use_accept_mutex
#if (NGX_HAVE_REUSEPORT)
&& !ls[i].reuseport
#endif
) //如果是单进程方式
{
continue;
}
/*
将监听对象连接的读事件添加到事件驱动模块中，这样，epoll等事件模块就开始检测监听服务，并开始向用户提供服务了。
*/ //如果ngx_use_accept_mutex为0也就是未开启accept_mutex锁，则在ngx_worker_process_init->ngx_event_process_init 中把accept连接读事件统计到epoll中
//否则在ngx_process_events_and_timers->ngx_process_events_and_timers->ngx_trylock_accept_mutex中把accept连接读事件统计到epoll中
char tmpbuf[256];
snprintf(tmpbuf, sizeof(tmpbuf), "<%25s, %5d> epoll NGX_READ_EVENT(et) read add", NGX_FUNC_LINE);
ngx_log_debug0(NGX_LOG_DEBUG_EVENT, cycle->log, 0, tmpbuf);
if (ngx_add_event(rev, NGX_READ_EVENT, 0) == NGX_ERROR) { //如果是epoll则为ngx_epoll_add_event
return NGX_ERROR;
}
#endif
}
return NGX_OK;
}
//每一个worker进程开始初始化的函数
static ngx_int_t
ngx_event_process_init(ngx_cycle_t *cycle)
{
ngx_uint_t m, i;
ngx_event_t *rev, *wev;
ngx_listening_t *ls;
ngx_connection_t *c, *next, *old;
ngx_core_conf_t *ccf;
ngx_event_conf_t *ecf;
ngx_event_module_t *module;
//获得相应模块的配置结构
ccf = (ngx_core_conf_t *) ngx_get_conf(cycle->conf_ctx, ngx_core_module);
ecf = ngx_event_get_conf(cycle->conf_ctx, ngx_event_core_module);
//accept_mutex为1时才会使用互斥体
if (ccf->master && ccf->worker_processes > 1 && ecf->accept_mutex) { //当工作进程数目大于1时，用于开启负载均衡情况下，才设置该变量
ngx_use_accept_mutex = 1; //1表示使用互斥体
ngx_accept_mutex_held = 0; //表示是否获得互斥体
ngx_accept_mutex_delay = ecf->accept_mutex_delay; //抢占失败以后，下次再抢的时间，延迟的时间
} else {
ngx_use_accept_mutex = 0; //表示不使用互斥体
}
#if (NGX_THREADS)
ngx_posted_events_mutex = ngx_mutex_init(cycle->log, 0);
if (ngx_posted_events_mutex == NULL) {
return NGX_ERROR;
}
#endif
//初始化定时器，这里将会初始化一个红黑树来管理
if (ngx_event_timer_init(cycle->log) == NGX_ERROR) {
return NGX_ERROR;
}
for (m = 0; ngx_modules[m]; m++) {
if (ngx_modules[m]->type != NGX_EVENT_MODULE) {
continue;
}
if (ngx_modules[m]->ctx_index != ecf->use) { //不是use配置项指定的事件跳过
continue;
}
module = ngx_modules[m]->ctx;
//调用具体事件模块的函数，如epoll机制的ngx_epoll_init
if (module->actions.init(cycle, ngx_timer_resolution) != NGX_OK) {
/* fatal */
exit(2);
}
break;
}
#if !(NGX_WIN32)
//如果设置了timer_resolution配置项，表明要控制时间精度，调用setitimer
if (ngx_timer_resolution && !(ngx_event_flags & NGX_USE_TIMER_EVENT)) {
struct sigaction sa;
struct itimerval itv;
ngx_memzero(&sa, sizeof(struct sigaction));
sa.sa_handler = ngx_timer_signal_handler;
sigemptyset(&sa.sa_mask);
if (sigaction(SIGALRM, &sa, NULL) == -1) {
ngx_log_error(NGX_LOG_ALERT, cycle->log, ngx_errno,
"sigaction(SIGALRM) failed");
return NGX_ERROR;
}
itv.it_interval.tv_sec = ngx_timer_resolution / 1000; //秒
itv.it_interval.tv_usec = (ngx_timer_resolution % 1000) * 1000; //微妙
itv.it_value.tv_sec = ngx_timer_resolution / 1000; //循环周期的数
itv.it_value.tv_usec = (ngx_timer_resolution % 1000 ) * 1000;
if (setitimer(ITIMER_REAL, &itv, NULL) == -1) {
ngx_log_error(NGX_LOG_ALERT, cycle->log, ngx_errno,
"setitimer() failed");
}
}
if (ngx_event_flags & NGX_USE_FD_EVENT) {
struct rlimit rlmt;
if (getrlimit(RLIMIT_NOFILE, &rlmt) == -1) {
ngx_log_error(NGX_LOG_ALERT, cycle->log, ngx_errno,
"getrlimit(RLIMIT_NOFILE) failed");
return NGX_ERROR;
}
cycle->files_n = (ngx_uint_t) rlmt.rlim_cur;
//file成员
cycle->files = ngx_calloc(sizeof(ngx_connection_t *) * cycle->files_n,
cycle->log);
if (cycle->files == NULL) {
return NGX_ERROR;
}
}
#endif
//创建一个connections数组，直接通过malloc
cycle->connections =
ngx_alloc(sizeof(ngx_connection_t) * cycle->connection_n, cycle->log);
if (cycle->connections == NULL) {
return NGX_ERROR;
}
c = cycle->connections;
//创建一个读事件数组
cycle->read_events = ngx_alloc(sizeof(ngx_event_t) * cycle->connection_n,
cycle->log);
if (cycle->read_events == NULL) {
return NGX_ERROR;
}
rev = cycle->read_events;
for (i = 0; i < cycle->connection_n; i++) {
rev[i].closed = 1;
rev[i].instance = 1;
#if (NGX_THREADS)
rev[i].lock = &c[i].lock;
rev[i].own_lock = &c[i].lock;
#endif
}
//创建一个写事件数组
cycle->write_events = ngx_alloc(sizeof(ngx_event_t) * cycle->connection_n,
cycle->log);
if (cycle->write_events == NULL) {
return NGX_ERROR;
}
wev = cycle->write_events;
for (i = 0; i < cycle->connection_n; i++) {
wev[i].closed = 1;
#if (NGX_THREADS)
wev[i].lock = &c[i].lock;
wev[i].own_lock = &c[i].lock;
#endif
}
i = cycle->connection_n;
next = NULL;
//初始化整个connections数组
do {
i--;
c[i].data = next; //串联起来
c[i].read = &cycle->read_events[i];
c[i].write = &cycle->write_events[i];
c[i].fd = (ngx_socket_t) -1;
next = &c[i];
#if (NGX_THREADS)
c[i].lock = 0;
#endif
} while (i);
cycle->free_connections = next; //指向一个可用的slot
cycle->free_connection_n = cycle->connection_n;
/* for each listening socket */
//为每一个监听套接字分配一个connection
ls = cycle->listening.elts;
for (i = 0; i < cycle->listening.nelts; i++) {
c = ngx_get_connection(ls[i].fd, cycle->log); //获得一个可用的connection
//对于每一个监听套接口创建对应的connection连接对象
if (c == NULL) {
return NGX_ERROR;
}
c->log = &ls[i].log;
c->listening = &ls[i];
ls[i].connection = c;
rev = c->read;
rev->log = c->log;
rev->accept = 1; //读事件发生
#if (NGX_HAVE_DEFERRED_ACCEPT)
rev->deferred_accept = ls[i].deferred_accept;
#endif
if (!(ngx_event_flags & NGX_USE_IOCP_EVENT)) {
if (ls[i].previous) {
/*
* delete the old accept events that were bound to
* the old cycle read events array
*/
old = ls[i].previous->connection;
if (ngx_del_event(old->read, NGX_READ_EVENT, NGX_CLOSE_EVENT)
== NGX_ERROR)
{
return NGX_ERROR;
}
old->fd = (ngx_socket_t) -1;
}
}
#if (NGX_WIN32)
if (ngx_event_flags & NGX_USE_IOCP_EVENT) {
ngx_iocp_conf_t *iocpcf;
rev->handler = ngx_event_acceptex;
if (ngx_use_accept_mutex) {
continue;
}
if (ngx_add_event(rev, 0, NGX_IOCP_ACCEPT) == NGX_ERROR) {
return NGX_ERROR;
}
ls[i].log.handler = ngx_acceptex_log_error;
iocpcf = ngx_event_get_conf(cycle->conf_ctx, ngx_iocp_module);
if (ngx_event_post_acceptex(&ls[i], iocpcf->post_acceptex)
== NGX_ERROR)
{
return NGX_ERROR;
}
} else {
rev->handler = ngx_event_accept;
if (ngx_use_accept_mutex) {
continue;
}
if (ngx_add_event(rev, NGX_READ_EVENT, 0) == NGX_ERROR) {
return NGX_ERROR;
}
}
#else
//ngx_process_events_and_timers
rev->handler = ngx_event_accept; //监听套接字的读事件回调
if (ngx_use_accept_mutex) { //设置了该参数，也就跳过了后面的将监听套接口添加到事件监控事件里，避免惊群
continue;
}
if (ngx_event_flags & NGX_USE_RTSIG_EVENT) {
if (ngx_add_conn(c) == NGX_ERROR) {
return NGX_ERROR;
}
} else {
//没有使用accept_mutex时，就将监听套接字放入到epoll中
if (ngx_add_event(rev, NGX_READ_EVENT, 0) == NGX_ERROR) {
return NGX_ERROR;
}
}
#endif
}
return NGX_OK;
}
/* 事件驱动模块初始化，也就是worker进程初始化时会调用到这里 */
static ngx_int_t
ngx_event_process_init(ngx_cycle_t *cycle)
{
ngx_uint_t m, i;
ngx_event_t *rev, *wev;
ngx_listening_t *ls;
ngx_connection_t *c, *next, *old;
ngx_core_conf_t *ccf;
ngx_event_conf_t *ecf;
ngx_event_module_t *module;
ccf = (ngx_core_conf_t *) ngx_get_conf(cycle->conf_ctx, ngx_core_module);
ecf = ngx_event_get_conf(cycle->conf_ctx, ngx_event_core_module);
if (ccf->master && ccf->worker_processes > 1 && ecf->accept_mutex) {
ngx_use_accept_mutex = 1;
ngx_accept_mutex_held = 0;
ngx_accept_mutex_delay = ecf->accept_mutex_delay;
} else {
ngx_use_accept_mutex = 0;
}
#if (NGX_WIN32)
/*
* disable accept mutex on win32 as it may cause deadlock if
* grabbed by a process which can't accept connections
*/
ngx_use_accept_mutex = 0;
#endif
/* 初始化两个时间接收队列 */
ngx_queue_init(&ngx_posted_accept_events);
ngx_queue_init(&ngx_posted_events);
/* 事件模型的时钟初始化 */
if (ngx_event_timer_init(cycle->log) == NGX_ERROR) {
return NGX_ERROR;
}
for (m = 0; ngx_modules[m]; m++) {
if (ngx_modules[m]->type != NGX_EVENT_MODULE) {
continue;
}
if (ngx_modules[m]->ctx_index != ecf->use) {
continue;
}
module = ngx_modules[m]->ctx;
/* 调用事件模型的初始化回调 */
if (module->actions.init(cycle, ngx_timer_resolution) != NGX_OK) {
/* fatal */
exit(2);
}
break;
}
#if !(NGX_WIN32)
if (ngx_timer_resolution && !(ngx_event_flags & NGX_USE_TIMER_EVENT)) {
struct sigaction sa;
struct itimerval itv;
ngx_memzero(&sa, sizeof(struct sigaction));
sa.sa_handler = ngx_timer_signal_handler;
sigemptyset(&sa.sa_mask);
if (sigaction(SIGALRM, &sa, NULL) == -1) {
ngx_log_error(NGX_LOG_ALERT, cycle->log, ngx_errno,
"sigaction(SIGALRM) failed");
return NGX_ERROR;
}
itv.it_interval.tv_sec = ngx_timer_resolution / 1000;
itv.it_interval.tv_usec = (ngx_timer_resolution % 1000) * 1000;
itv.it_value.tv_sec = ngx_timer_resolution / 1000;
itv.it_value.tv_usec = (ngx_timer_resolution % 1000 ) * 1000;
if (setitimer(ITIMER_REAL, &itv, NULL) == -1) {
ngx_log_error(NGX_LOG_ALERT, cycle->log, ngx_errno,
"setitimer() failed");
}
}
if (ngx_event_flags & NGX_USE_FD_EVENT) {
struct rlimit rlmt;
/* RLIMIT_NOFILE表示一个进程能打开的最大文件数 */
if (getrlimit(RLIMIT_NOFILE, &rlmt) == -1) {
ngx_log_error(NGX_LOG_ALERT, cycle->log, ngx_errno,
"getrlimit(RLIMIT_NOFILE) failed");
return NGX_ERROR;
}
cycle->files_n = (ngx_uint_t) rlmt.rlim_cur;
cycle->files = ngx_calloc(sizeof(ngx_connection_t *) * cycle->files_n,
cycle->log);
if (cycle->files == NULL) {
return NGX_ERROR;
}
}
#else
if (ngx_timer_resolution && !(ngx_event_flags & NGX_USE_TIMER_EVENT)) {
ngx_log_error(NGX_LOG_WARN, cycle->log, 0,
"the \"timer_resolution\" directive is not supported "
"with the configured event method, ignored");
ngx_timer_resolution = 0;
}
#endif
cycle->connections =
ngx_alloc(sizeof(ngx_connection_t) * cycle->connection_n, cycle->log);
if (cycle->connections == NULL) {
return NGX_ERROR;
}
c = cycle->connections;
/* 分配读事件 */
cycle->read_events = ngx_alloc(sizeof(ngx_event_t) * cycle->connection_n,
cycle->log);
if (cycle->read_events == NULL) {
return NGX_ERROR;
}
rev = cycle->read_events;
/* 初始化所有的连接的连接状态为关闭 */
for (i = 0; i < cycle->connection_n; i++) {
rev[i].closed = 1;
rev[i].instance = 1;
}
/* 分配和连接个数相同的写事件 */
cycle->write_events = ngx_alloc(sizeof(ngx_event_t) * cycle->connection_n,
cycle->log);
if (cycle->write_events == NULL) {
return NGX_ERROR;
}
wev = cycle->write_events;
for (i = 0; i < cycle->connection_n; i++) {
wev[i].closed = 1;
}
i = cycle->connection_n;
next = NULL;
do {
i--;
c[i].data = next;
/* 设置连接的读事件和写事件 */
c[i].read = &cycle->read_events[i];
c[i].write = &cycle->write_events[i];
c[i].fd = (ngx_socket_t) -1;
next = &c[i];
} while (i);
/* 刚开始设置所有的连接为空闲连接 */
cycle->free_connections = next;
cycle->free_connection_n = cycle->connection_n;
/* for each listening socket */
ls = cycle->listening.elts;
/* 循环处理监听套接字，也就是监听套接字的事件处理为ngx_event_accept函数 */
for (i = 0; i < cycle->listening.nelts; i++) {
#if (NGX_HAVE_REUSEPORT)
if (ls[i].reuseport && ls[i].worker != ngx_worker) {
continue;
}
#endif
/* 获取每个监听套接字对应的连接 */
c = ngx_get_connection(ls[i].fd, cycle->log);
if (c == NULL) {
return NGX_ERROR;
}
c->log = &ls[i].log;
c->listening = &ls[i];
ls[i].connection = c;
rev = c->read;
rev->log = c->log;
rev->accept = 1;
#if (NGX_HAVE_DEFERRED_ACCEPT)
rev->deferred_accept = ls[i].deferred_accept;
#endif
if (!(ngx_event_flags & NGX_USE_IOCP_EVENT)) {
if (ls[i].previous) {
/*
* delete the old accept events that were bound to
* the old cycle read events array
*/
old = ls[i].previous->connection;
if (ngx_del_event(old->read, NGX_READ_EVENT, NGX_CLOSE_EVENT)
== NGX_ERROR)
{
return NGX_ERROR;
}
old->fd = (ngx_socket_t) -1;
}
}
#if (NGX_WIN32)
if (ngx_event_flags & NGX_USE_IOCP_EVENT) {
ngx_iocp_conf_t *iocpcf;
rev->handler = ngx_event_acceptex;
if (ngx_use_accept_mutex) {
continue;
}
if (ngx_add_event(rev, 0, NGX_IOCP_ACCEPT) == NGX_ERROR) {
return NGX_ERROR;
}
ls[i].log.handler = ngx_acceptex_log_error;
iocpcf = ngx_event_get_conf(cycle->conf_ctx, ngx_iocp_module);
if (ngx_event_post_acceptex(&ls[i], iocpcf->post_acceptex)
== NGX_ERROR)
{
return NGX_ERROR;
}
} else {
rev->handler = ngx_event_accept;
if (ngx_use_accept_mutex) {
continue;
}
if (ngx_add_event(rev, NGX_READ_EVENT, 0) == NGX_ERROR) {
return NGX_ERROR;
}
}
#else
rev->handler = ngx_event_accept;
if (ngx_use_accept_mutex
#if (NGX_HAVE_REUSEPORT)
&& !ls[i].reuseport
#endif
)
{
continue;
}
if (ngx_add_event(rev, NGX_READ_EVENT, 0) == NGX_ERROR) {
return NGX_ERROR;
}
#endif
}
return NGX_OK;
}
//初始化事件处理函数
static ngx_int_t
ngx_event_process_init(ngx_cycle_t *cycle)
{
ngx_uint_t m, i;
ngx_event_t *rev, *wev;
ngx_listening_t *ls;
ngx_connection_t *c, *next, *old;
ngx_core_conf_t *ccf;
ngx_event_conf_t *ecf;
ngx_event_module_t *module;
ccf = (ngx_core_conf_t *) ngx_get_conf(cycle->conf_ctx, ngx_core_module);
ecf = ngx_event_get_conf(cycle->conf_ctx, ngx_event_core_module);
if (ccf->master && ccf->worker_processes > 1 && ecf->accept_mutex) {
//使用锁机制
ngx_use_accept_mutex = 1;
//是否获得accept互斥锁
ngx_accept_mutex_held = 0;
//获取锁失败后，等待下次执行的时间
ngx_accept_mutex_delay = ecf->accept_mutex_delay;
} else {
ngx_use_accept_mutex = 0;
}
#if (NGX_WIN32)
/*
* disable accept mutex on win32 as it may cause deadlock if
* grabbed by a process which can't accept connections
*/
ngx_use_accept_mutex = 0;
#endif
//初始化accept请求队列（使用accept锁）
ngx_queue_init(&ngx_posted_accept_events);
ngx_queue_init(&ngx_posted_events);
if (ngx_event_timer_init(cycle->log) == NGX_ERROR) {
return NGX_ERROR;
}
//初始化事件驱动模块
for (m = 0; cycle->modules[m]; m++) {
/*循环事件驱动模块，跳过模块类型为非NGX_EVENT_MODULE类型的模块*/
//调用event/modules/*.c
if (cycle->modules[m]->type != NGX_EVENT_MODULE) {
continue;
}
//如果非当前使用的模块则跳过( ngx_event_core_init_conf 定义)
if (cycle->modules[m]->ctx_index != ecf->use) {
continue;
}
module = cycle->modules[m]->ctx;
//初始化事件驱动
if (module->actions.init(cycle, ngx_timer_resolution) != NGX_OK) {
/* fatal */
exit(2);
}
break;
}
#if !(NGX_WIN32)
if (ngx_timer_resolution && !(ngx_event_flags & NGX_USE_TIMER_EVENT)) {
struct sigaction sa;
struct itimerval itv;
ngx_memzero(&sa, sizeof(struct sigaction));
sa.sa_handler = ngx_timer_signal_handler;
sigemptyset(&sa.sa_mask);
if (sigaction(SIGALRM, &sa, NULL) == -1) {
ngx_log_error(NGX_LOG_ALERT, cycle->log, ngx_errno,
"sigaction(SIGALRM) failed");
return NGX_ERROR;
}
itv.it_interval.tv_sec = ngx_timer_resolution / 1000;
itv.it_interval.tv_usec = (ngx_timer_resolution % 1000) * 1000;
itv.it_value.tv_sec = ngx_timer_resolution / 1000;
itv.it_value.tv_usec = (ngx_timer_resolution % 1000 ) * 1000;
if (setitimer(ITIMER_REAL, &itv, NULL) == -1) {
ngx_log_error(NGX_LOG_ALERT, cycle->log, ngx_errno,
"setitimer() failed");
}
}
if (ngx_event_flags & NGX_USE_FD_EVENT) {
struct rlimit rlmt;
if (getrlimit(RLIMIT_NOFILE, &rlmt) == -1) {
ngx_log_error(NGX_LOG_ALERT, cycle->log, ngx_errno,
"getrlimit(RLIMIT_NOFILE) failed");
return NGX_ERROR;
}
cycle->files_n = (ngx_uint_t) rlmt.rlim_cur;
cycle->files = ngx_calloc(sizeof(ngx_connection_t *) * cycle->files_n,
cycle->log);
if (cycle->files == NULL) {
return NGX_ERROR;
}
}
#else
if (ngx_timer_resolution && !(ngx_event_flags & NGX_USE_TIMER_EVENT)) {
ngx_log_error(NGX_LOG_WARN, cycle->log, 0,
"the \"timer_resolution\" directive is not supported "
"with the configured event method, ignored");
ngx_timer_resolution = 0;
}
#endif
//创建connections数组，保存连接信息
cycle->connections =
ngx_alloc(sizeof(ngx_connection_t) * cycle->connection_n, cycle->log);
if (cycle->connections == NULL) {
return NGX_ERROR;
}
c = cycle->connections;
//创建读事件数组
cycle->read_events = ngx_alloc(sizeof(ngx_event_t) * cycle->connection_n,
cycle->log);
if (cycle->read_events == NULL) {
return NGX_ERROR;
}
rev = cycle->read_events;
for (i = 0; i < cycle->connection_n; i++) {
rev[i].closed = 1;
rev[i].instance = 1;
}
//创建写事件数组
cycle->write_events = ngx_alloc(sizeof(ngx_event_t) * cycle->connection_n,
cycle->log);
if (cycle->write_events == NULL) {
return NGX_ERROR;
}
wev = cycle->write_events;
for (i = 0; i < cycle->connection_n; i++) {
wev[i].closed = 1;
}
i = cycle->connection_n;
next = NULL;
do {
i--;
c[i].data = next;
c[i].read = &cycle->read_events[i];
c[i].write = &cycle->write_events[i];
c[i].fd = (ngx_socket_t) -1;
next = &c[i];
} while (i);
//初始化完成后，free_connections指向 cycle->connections第一个元素
cycle->free_connections = next;
//设置剩余连接数
cycle->free_connection_n = cycle->connection_n;
/* for each listening socket */
ls = cycle->listening.elts;
for (i = 0; i < cycle->listening.nelts; i++) {
#if (NGX_HAVE_REUSEPORT)
if (ls[i].reuseport && ls[i].worker != ngx_worker) {
continue;
}
#endif
c = ngx_get_connection(ls[i].fd, cycle->log);
if (c == NULL) {
return NGX_ERROR;
}
c->type = ls[i].type;
c->log = &ls[i].log;
c->listening = &ls[i];
ls[i].connection = c;
rev = c->read;
rev->log = c->log;
rev->accept = 1;
#if (NGX_HAVE_DEFERRED_ACCEPT)
rev->deferred_accept = ls[i].deferred_accept;
#endif
if (!(ngx_event_flags & NGX_USE_IOCP_EVENT)) {
if (ls[i].previous) {
/*
* delete the old accept events that were bound to
* the old cycle read events array
*/
old = ls[i].previous->connection;
if (ngx_del_event(old->read, NGX_READ_EVENT, NGX_CLOSE_EVENT)
== NGX_ERROR)
{
return NGX_ERROR;
}
old->fd = (ngx_socket_t) -1;
}
}
#if (NGX_WIN32)
if (ngx_event_flags & NGX_USE_IOCP_EVENT) {
ngx_iocp_conf_t *iocpcf;
rev->handler = ngx_event_acceptex;
if (ngx_use_accept_mutex) {
continue;
}
if (ngx_add_event(rev, 0, NGX_IOCP_ACCEPT) == NGX_ERROR) {
return NGX_ERROR;
}
ls[i].log.handler = ngx_acceptex_log_error;
iocpcf = ngx_event_get_conf(cycle->conf_ctx, ngx_iocp_module);
if (ngx_event_post_acceptex(&ls[i], iocpcf->post_acceptex)
== NGX_ERROR)
{
return NGX_ERROR;
}
} else {
rev->handler = ngx_event_accept;
if (ngx_use_accept_mutex) {
continue;
}
if (ngx_add_event(rev, NGX_READ_EVENT, 0) == NGX_ERROR) {
return NGX_ERROR;
}
}
#else
//设置回调函数
rev->handler = (c->type == SOCK_STREAM) ? ngx_event_accept
: ngx_event_recvmsg;
if (ngx_use_accept_mutex
#if (NGX_HAVE_REUSEPORT)
&& !ls[i].reuseport
#endif
)
{
continue;
}
//添加事件
if (ngx_add_event(rev, NGX_READ_EVENT, 0) == NGX_ERROR) {
return NGX_ERROR;
}
#endif
}
return NGX_OK;
}
