nginx启动初始化代码执行流程是什么

这篇文章主要介绍“nginx启动初始化代码执行流程是什么”，在日常操作中，相信很多人在nginx启动初始化代码执行流程是什么问题上存在疑惑，小编查阅了各式资料，整理出简单好用的操作方法，希望对大家解答”nginx启动初始化代码执行流程是什么”的疑惑有所帮助！接下来，请跟着小编一起来学习吧！

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代码执行流程

ngx_event_process_init：遍历connections，初始化listenfd的回调函数，添加事件监听

static ngx_int_t

ngx_event_process_init(ngx_cycle_t *cycle)

{

...

cycle->connections =

ngx_alloc(sizeof(ngx_connection_t) * cycle->connection_n, cycle->log);

cycle->read_events = ngx_alloc(sizeof(ngx_event_t) * cycle->connection_n,

cycle->log);

...

ls = cycle->listening.elts;

for (i = 0; i < cycle->listening.nelts; i++) {

c = ngx_get_connection(ls[i].fd, cycle->log);

c->listening = &ls[i];

rev = c->read;

}

...

rev->handler = ngx_event_accept;

ngx_add_event(rev, NGX_READ_EVENT, 0)

...

}

ngx_event_accept:调用ngx_listening_t的回调函数

void

ngx_event_accept(ngx_event_t *ev)

{

...

lc = ev->data;

ls = lc->listening;

...

s = accept(lc->fd, (struct sockaddr *) sa, &socklen);

c = ngx_get_connection(s, ev->log);

ngx_add_conn(c)

ls->handler(c);

...

}

找到ls->handler(c)的位置

static char *

ngx_http_block(ngx_conf_t *cf, ngx_command_t *cmd, void *conf)

{

...

if (ngx_http_optimize_servers(cf, cmcf, cmcf->ports) != NGX_OK) {

return NGX_CONF_ERROR;

}

...

}

static ngx_int_t

ngx_http_optimize_servers(ngx_conf_t *cf, ngx_http_core_main_conf_t *cmcf,

ngx_array_t *ports)

{

...

if (ngx_http_init_listening(cf, &port[p]) != NGX_OK) {

return NGX_ERROR;

}

...

}

static ngx_int_t

ngx_http_init_listening(ngx_conf_t *cf, ngx_http_conf_port_t *port)

{

...

ls = ngx_http_add_listening(cf, &addr[i]);

if (ls == NULL) {

return NGX_ERROR;

}

...

}

static ngx_listening_t *

ngx_http_add_listening(ngx_conf_t *cf, ngx_http_conf_addr_t *addr)

{

...

ls->handler = ngx_http_init_connection;

...

}

第三方模块（输出）：

server {

listen 0.0.0.0:70;

location / {

root /usr/local/nginx/html/bak/;

limit_req zone=req10k burst=5 nodelay;

shuchu "helloworld";

}

一个模块的三大核心

static ngx_command_t ngx_http_shuchu_commands[] = {

{

ngx_string("shuchu"),

NGX_HTTP_LOC_CONF|NGX_CONF_TAKE1,

ngx_http_shuchu,

NGX_HTTP_LOC_CONF_OFFSET,

offsetof(ngx_http_shuchu_loc_conf_t, content),

NULL,

ngx_null_command,

};

static ngx_http_module_t ngx_http_shuchu_ctx = {

NULL,

ngx_http_shuchu_init,

NULL,

ngx_http_shuchu_create_loc_conf,

ngx_http_shuchu_merge_loc_conf

};

ngx_module_t ngx_http_shuchu_module = {

NGX_MODULE_V1,

&ngx_http_shuchu_ctx, /* module context */

ngx_http_shuchu_commands, /* module directives */

NGX_HTTP_MODULE, /* module type */

NULL, /* init master */

NULL, /* init module */

NULL, /* init process */

NULL, /* init thread */

NULL, /* exit thread */

NULL, /* exit process */

NULL, /* exit master */

NGX_MODULE_V1_PADDING

};

ngx_conf_parse:解析配置

char *

ngx_conf_parse(ngx_conf_t *cf, ngx_str_t *filename)

{

...

type = parse_file;

fd = ngx_open_file(filename->data, NGX_FILE_RDONLY, NGX_FILE_OPEN, 0);

rc = ngx_conf_read_token(cf);

省略对rc和type组合的判定

rc = ngx_conf_handler(cf, rc);

...

}

ngx_conf_handler:对指令进行处理

static ngx_int_t

ngx_conf_handler(ngx_conf_t *cf, ngx_int_t last)

{

...

for (i = 0; ngx_modules[i]; i++) {

cmd = ngx_modules[i]->commands;

for ( /* void */ ; cmd->name.len; cmd++) {

if (cmd->type & NGX_DIRECT_CONF) {

conf = ((void **) cf->ctx)[ngx_modules[i]->index];

} else if (cmd->type & NGX_MAIN_CONF) {

conf = &(((void **) cf->ctx)[ngx_modules[i]->index]);

} else if (cf->ctx) {

confp = *(void **) ((char *) cf->ctx + cmd->conf);

if (confp) {

conf = confp[ngx_modules[i]->ctx_index];

}

rv = cmd->set(cf, cmd, conf);

}

...

}

ngx_http_block

static char *

ngx_http_block(ngx_conf_t *cf, ngx_command_t *cmd, void *conf)

{

...

ctx->main_conf = ngx_pcalloc(cf->pool, sizeof(void *) * ngx_http_max_module);

ctx->srv_conf = ngx_pcalloc(cf->pool, sizeof(void *) * ngx_http_max_module);

ctx->loc_conf = ngx_pcalloc(cf->pool, sizeof(void *) * ngx_http_max_module);

for (m = 0; ngx_modules[m]; m++) {

if (ngx_modules[m]->type != NGX_HTTP_MODULE) {

continue;

}

module = ngx_modules[m]->ctx;

mi = ngx_modules[m]->ctx_index;

if (module->create_main_conf) {

ctx->main_conf[mi] = module->create_main_conf(cf);

if (ctx->main_conf[mi] == NULL) {

return NGX_CONF_ERROR;

}

if (module->create_srv_conf) {

ctx->srv_conf[mi] = module->create_srv_conf(cf);

if (ctx->srv_conf[mi] == NULL) {

return NGX_CONF_ERROR;

}

if (module->create_loc_conf) {

ctx->loc_conf[mi] = module->create_loc_conf(cf);

if (ctx->loc_conf[mi] == NULL) {

return NGX_CONF_ERROR;

}

pcf = *cf;

cf->ctx = ctx;

...

/* parse inside the http{} block */

cf->module_type = NGX_HTTP_MODULE;

cf->cmd_type = NGX_HTTP_MAIN_CONF;

rv = ngx_conf_parse(cf, NULL);

...

}

ngx_http_core_server

static char *

ngx_http_core_server(ngx_conf_t *cf, ngx_command_t *cmd, void *dummy)

{

...

ctx = ngx_pcalloc(cf->pool, sizeof(ngx_http_conf_ctx_t));

if (ctx == NULL) {

return NGX_CONF_ERROR;

}

http_ctx = cf->ctx;

ctx->main_conf = http_ctx->main_conf;

ctx->srv_conf = ngx_pcalloc(cf->pool, sizeof(void *) * ngx_http_max_module);

ctx->loc_conf = ngx_pcalloc(cf->pool, sizeof(void *) * ngx_http_max_module);

...

cscf = ctx->srv_conf[ngx_http_core_module.ctx_index];

cscf->ctx = ctx;

cmcf = ctx->main_conf[ngx_http_core_module.ctx_index];

cscfp = ngx_array_push(&cmcf->servers);

if (cscfp == NULL) {

return NGX_CONF_ERROR;

}

*cscfp = cscf;

/* parse inside server{} */

pcf = *cf;

cf->ctx = ctx;

cf->cmd_type = NGX_HTTP_SRV_CONF;

rv = ngx_conf_parse(cf, NULL);

...

}

ngx_http_core_listen

static char *

ngx_http_core_listen(ngx_conf_t *cf, ngx_command_t *cmd, void *conf)

{

...

cscf->listen = 1;

value = cf->args->elts;

ngx_memzero(&u, sizeof(ngx_url_t));

u.url = value[1];

ngx_parse_url(cf->pool, &u);

if (ngx_http_add_listen(cf, cscf, &lsopt) == NGX_OK) {

return NGX_CONF_OK;

}

...

}

ngx_http_add_listen

ngx_int_t

ngx_http_add_listen(ngx_conf_t *cf, ngx_http_core_srv_conf_t *cscf,

ngx_http_listen_opt_t *lsopt)

{

...

cmcf = ngx_http_conf_get_module_main_conf(cf, ngx_http_core_module);

if (cmcf->ports == NULL) {

cmcf->ports = ngx_array_create(cf->temp_pool, 2,

sizeof(ngx_http_conf_port_t));

if (cmcf->ports == NULL) {

return NGX_ERROR;

}

sin = &lsopt->u.sockaddr_in;

p = sin->sin_port;

port = ngx_array_push(cmcf->ports);

port->family = sa->sa_family;

port->port = p;

port->addrs.elts = NULL;

ngx_http_add_address(cf, cscf, port, lsopt);

...

}

ngx_http_add_address

static ngx_int_t

ngx_http_add_address(ngx_conf_t *cf, ngx_http_core_srv_conf_t *cscf,

ngx_http_conf_port_t *port, ngx_http_listen_opt_t *lsopt)

{

...

addr = ngx_array_push(&port->addrs);

addr->opt = *lsopt;

addr->default_server = cscf;

...}

ngx_http_add_server

static ngx_int_t

ngx_http_add_server(ngx_conf_t *cf, ngx_http_core_srv_conf_t *cscf,

ngx_http_conf_addr_t *addr)

{

...

server = ngx_array_push(&addr->servers);

*server = cscf;

...

}

到这里为止，整个配置的基本架构已经搞起来了，port（ngx_http_conf_port_t）下挂着多个监听的地址（ngx_http_conf_addr_t），每个地址后的opt目前都是配置里面读出来，存着监听器的信息，监听地址（ngx_http_conf_addr_t）后面还挂着这个监听地址所存在的server块（ngx_http_core_srv_conf_t），接下来就要最后在optmize一下，把opt里的东西搞一下，然后做hash：

ngx_http_optimize_servers

static ngx_int_t

ngx_http_optimize_servers(ngx_conf_t *cf, ngx_http_core_main_conf_t *cmcf,

ngx_array_t *ports)

{

...

port = ports->elts;

for (p = 0; p < ports->nelts; p++) {

addr = port[p].addrs.elts;

for (a = 0; a < port[p].addrs.nelts; a++) {

if (ngx_http_server_names(cf, cmcf, &addr[a]) != NGX_OK) {

return NGX_ERROR;

}

if (ngx_http_init_listening(cf, &port[p]) != NGX_OK) {

return NGX_ERROR;

}

...

}

ngx_http_server_names:整理addr中的servers，将sn和对应的srv_conf对应起来

static ngx_int_t

ngx_http_optimize_servers(ngx_conf_t *cf, ngx_http_core_main_conf_t *cmcf,

ngx_array_t *ports)

{

...

ha.pool = cf->pool;

cscfp = addr->servers.elts;

for (s = 0; s < addr->servers.nelts; s++) {

name = cscfp[s]->server_names.elts;

for (n = 0; n < cscfp[s]->server_names.nelts; n++) {

rc = ngx_hash_add_key(&ha, &name[n].name, name[n].server,

NGX_HASH_WILDCARD_KEY);

}

...

hash.hash = &addr->hash;

ngx_hash_init(&hash, ha.keys.elts, ha.keys.nelts);

}

...

}

ngx_http_add_listening

static ngx_listening_t *

ngx_http_add_listening(ngx_conf_t *cf, ngx_http_conf_addr_t *addr)

{

...

ls = ngx_create_listening(cf, &addr->opt.u.sockaddr, addr->opt.socklen);

ls->handler = ngx_http_init_connection;

...

}

instance

每次get_connection都会将instance取反,s是accept获取的socket，是一个int，赋值给c->fd

ngx_connection_t *

ngx_get_connection(ngx_socket_t s, ngx_log_t *log)

{

...

c = ngx_cycle->free_connections;

ngx_cycle->free_connections = c->data;

ngx_cycle->free_connection_n--;

rev = c->read;

wev = c->write;

ngx_memzero(c, sizeof(ngx_connection_t));

c->read = rev;

c->write = wev;

c->fd = s;

rev->instance = !instance;

wev->instance = !instance;

rev->data = c;

wev->data = c;

return c;

...

}

而free的时候只移动链表，清空文件，将当前链表变成可用

void

ngx_free_connection(ngx_connection_t *c)

{

...

c->data = ngx_cycle->free_connections;

ngx_cycle->free_connections = c;

ngx_cycle->free_connection_n++;

if (ngx_cycle->files) {

ngx_cycle->files[c->fd] = NULL;

...

}

而无论是add_event还是add_connection,都是直接将epoll指向的直接与instance，在process_events的时候，拿出来事件指向的

static ngx_int_t

ngx_epoll_add_event(ngx_event_t *ev, ngx_int_t event, ngx_uint_t flags)

{

...

ee.data.ptr = (void *) ((uintptr_t) c | ev->instance);

...

}

static ngx_int_t

ngx_epoll_process_events(ngx_cycle_t *cycle, ngx_msec_t timer, ngx_uint_t flags)

{

...

c = event_list[i].data.ptr;

instance = (uintptr_t) c & 1;

if (c->fd == -1 || rev->instance != instance) {

...

}

到此，关于“nginx启动初始化代码执行流程是什么”的学习就结束了，希望能够解决大家的疑惑。理论与实践的搭配能更好的帮助大家学习，快去试试吧！若想继续学习更多相关知识，请继续关注创新互联网站，小编会继续努力为大家带来更多实用的文章！

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