一、Nginx的http
1、遇到conf文件的http模块。http不是在Nginx的mian函数中启动，而是解析conf文件时遇到http才会去解析并启动。
2、请求到来时，调用http server。
二、Nginx 启动http Server流程
2.1、ngx_module_t
Nginx的http是以NGX_CORE_MODULE模块的方式加载到Nginx中，因此它定义成一个ngx_module_t（/src/http/ngx_http.c）：
static ngx_command_t ngx_http_commands[] = {
{
ngx_string("http"),
NGX_MAIN_CONF|NGX_CONF_BLOCK|NGX_CONF_NOARGS,
ngx_http_block,
0,
0,
NULL },
ngx_null_command
};
static ngx_core_module_t ngx_http_module_ctx = {
ngx_string("http"),
NULL,
NULL
};
ngx_module_t ngx_http_module = {
NGX_MODULE_V1,
&ngx_http_module_ctx, /* module context */
ngx_http_commands, /* module directives */
NGX_CORE_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
};
/src/core/ngx_module.h
#define NGX_MODULE_V1 \
NGX_MODULE_UNSET_INDEX, NGX_MODULE_UNSET_INDEX, \
NULL, 0, 0, nginx_version, NGX_MODULE_SIGNATURE
#define NGX_MODULE_V1_PADDING 0, 0, 0, 0, 0, 0, 0, 0
2.2、ngx_http_commands
当解析conf文件时，如果遇到“http”就会获取ngx_http_commands，执行ngx_http_block函数。
（/src/http/ngx_http.c）
static ngx_command_t ngx_http_commands[] = {
{
ngx_string("http"),
NGX_MAIN_CONF|NGX_CONF_BLOCK|NGX_CONF_NOARGS,
ngx_http_block,
0,
0,
NULL },
ngx_null_command
};
2.3、ngx_http_block
ngx_http_block相当于http的主函数，里面做了很多的初始化工作。其中在最后会调用一个ngx_http_optimize_servers的函数优化端口、地址和服务器名称列表。
（/src/http/ngx_http.c）
static char *
ngx_http_block(ngx_conf_t *cf, ngx_command_t *cmd, void *conf)
{
char *rv;
ngx_uint_t mi, m, s;
ngx_conf_t pcf;
ngx_http_module_t *module;
ngx_http_conf_ctx_t *ctx;
ngx_http_core_loc_conf_t *clcf;
ngx_http_core_srv_conf_t **cscfp;
ngx_http_core_main_conf_t *cmcf;
if (*(ngx_http_conf_ctx_t **) conf) {
return "is duplicate";
}
/* the main http context */
ctx = ngx_pcalloc(cf->pool, sizeof(ngx_http_conf_ctx_t));
if (ctx == NULL) {
return NGX_CONF_ERROR;
}
*(ngx_http_conf_ctx_t **) conf = ctx;
/* count the number of the http modules and set up their indices */
ngx_http_max_module = ngx_count_modules(cf->cycle, NGX_HTTP_MODULE);
/* the http main_conf context, it is the same in the all http contexts */
ctx->main_conf = ngx_pcalloc(cf->pool,
sizeof(void *) * ngx_http_max_module);
if (ctx->main_conf == NULL) {
return NGX_CONF_ERROR;
}
/*
* the http null srv_conf context, it is used to merge
* the server{}s' srv_conf's
*/
ctx->srv_conf = ngx_pcalloc(cf->pool, sizeof(void *) * ngx_http_max_module);
if (ctx->srv_conf == NULL) {
return NGX_CONF_ERROR;
}
/*
* the http null loc_conf context, it is used to merge
* the server{}s' loc_conf's
*/
ctx->loc_conf = ngx_pcalloc(cf->pool, sizeof(void *) * ngx_http_max_module);
if (ctx->loc_conf == NULL) {
return NGX_CONF_ERROR;
}
/*
* create the main_conf's, the null srv_conf's, and the null loc_conf's
* of the all http modules
*/
for (m = 0; cf->cycle->modules[m]; m++) {
if (cf->cycle->modules[m]->type != NGX_HTTP_MODULE) {
continue;
}
module = cf->cycle->modules[m]->ctx;
mi = cf->cycle->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;
for (m = 0; cf->cycle->modules[m]; m++) {
if (cf->cycle->modules[m]->type != NGX_HTTP_MODULE) {
continue;
}
module = cf->cycle->modules[m]->ctx;
if (module->preconfiguration) {
if (module->preconfiguration(cf) != NGX_OK) {
return NGX_CONF_ERROR;
}
}
}
/* parse inside the http{} block */
cf->module_type = NGX_HTTP_MODULE;
cf->cmd_type = NGX_HTTP_MAIN_CONF;
rv = ngx_conf_parse(cf, NULL);
if (rv != NGX_CONF_OK) {
goto failed;
}
/*
* init http{} main_conf's, merge the server{}s' srv_conf's
* and its location{}s' loc_conf's
*/
cmcf = ctx->main_conf[ngx_http_core_module.ctx_index];
cscfp = cmcf->servers.elts;
for (m = 0; cf->cycle->modules[m]; m++) {
if (cf->cycle->modules[m]->type != NGX_HTTP_MODULE) {
continue;
}
module = cf->cycle->modules[m]->ctx;
mi = cf->cycle->modules[m]->ctx_index;
/* init http{} main_conf's */
if (module->init_main_conf) {
rv = module->init_main_conf(cf, ctx->main_conf[mi]);
if (rv != NGX_CONF_OK) {
goto failed;
}
}
rv = ngx_http_merge_servers(cf, cmcf, module, mi);
if (rv != NGX_CONF_OK) {
goto failed;
}
}
/* create location trees */
for (s = 0; s < cmcf->servers.nelts; s++) {
clcf = cscfp[s]->ctx->loc_conf[ngx_http_core_module.ctx_index];
if (ngx_http_init_locations(cf, cscfp[s], clcf) != NGX_OK) {
return NGX_CONF_ERROR;
}
if (ngx_http_init_static_location_trees(cf, clcf) != NGX_OK) {
return NGX_CONF_ERROR;
}
}
if (ngx_http_init_phases(cf, cmcf) != NGX_OK) {
return NGX_CONF_ERROR;
}
if (ngx_http_init_headers_in_hash(cf, cmcf) != NGX_OK) {
return NGX_CONF_ERROR;
}
for (m = 0; cf->cycle->modules[m]; m++) {
if (cf->cycle->modules[m]->type != NGX_HTTP_MODULE) {
continue;
}
module = cf->cycle->modules[m]->ctx;
if (module->postconfiguration) {
if (module->postconfiguration(cf) != NGX_OK) {
return NGX_CONF_ERROR;
}
}
}
if (ngx_http_variables_init_vars(cf) != NGX_OK) {
return NGX_CONF_ERROR;
}
/*
* http{}'s cf->ctx was needed while the configuration merging
* and in postconfiguration process
*/
*cf = pcf;
if (ngx_http_init_phase_handlers(cf, cmcf) != NGX_OK) {
return NGX_CONF_ERROR;
}
/* optimize the lists of ports, addresses and server names */
if (ngx_http_optimize_servers(cf, cmcf, cmcf->ports) != NGX_OK) {
return NGX_CONF_ERROR;
}
return NGX_CONF_OK;
failed:
*cf = pcf;
return rv;
}
2.4、ngx_http_optimize_servers
ngx_http_optimize_servers里传入对应的端口启动http服务器。
（/src/http/ngx_http.c）
static ngx_int_t ngx_http_optimize_servers(ngx_conf_t *cf, ngx_http_core_main_conf_t *cmcf, ngx_array_t *ports)
{
ngx_uint_t p, a;
ngx_http_conf_port_t *port;
ngx_http_conf_addr_t *addr;
if (ports == NULL) {
return NGX_OK;
}
port = ports->elts;
for (p = 0; p < ports->nelts; p++) {
ngx_sort(port[p].addrs.elts, (size_t) port[p].addrs.nelts,
sizeof(ngx_http_conf_addr_t), ngx_http_cmp_conf_addrs);
/*
* check whether all name-based servers have the same
* configuration as a default server for given address:port
*/
addr = port[p].addrs.elts;
for (a = 0; a < port[p].addrs.nelts; a++) {
if (addr[a].servers.nelts > 1
#if (NGX_PCRE)
|| addr[a].default_server->captures
#endif
)
{
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;
}
}
return NGX_OK;
}
2.5、ngx_http_init_listening
在ngx_http_optimize_servers里调用ngx_http_init_listening函数监听。ngx_http_init_listening里面有一个while循环，根据端口调用ngx_http_add_listening进行监听。
（/src/http/ngx_http.c）
static ngx_int_t
ngx_http_init_listening(ngx_conf_t *cf, ngx_http_conf_port_t *port)
{
ngx_uint_t i, last, bind_wildcard;
ngx_listening_t *ls;
ngx_http_port_t *hport;
ngx_http_conf_addr_t *addr;
addr = port->addrs.elts;
last = port->addrs.nelts;
/*
* If there is a binding to an "*:port" then we need to bind() to
* the "*:port" only and ignore other implicit bindings. The bindings
* have been already sorted: explicit bindings are on the start, then
* implicit bindings go, and wildcard binding is in the end.
*/
if (addr[last - 1].opt.wildcard) {
addr[last - 1].opt.bind = 1;
bind_wildcard = 1;
} else {
bind_wildcard = 0;
}
i = 0;
while (i < last) {
if (bind_wildcard && !addr[i].opt.bind) {
i++;
continue;
}
ls = ngx_http_add_listening(cf, &addr[i]);
if (ls == NULL) {
return NGX_ERROR;
}
hport = ngx_pcalloc(cf->pool, sizeof(ngx_http_port_t));
if (hport == NULL) {
return NGX_ERROR;
}
ls->servers = hport;
hport->naddrs = i + 1;
switch (ls->sockaddr->sa_family) {
#if (NGX_HAVE_INET6)
case AF_INET6:
if (ngx_http_add_addrs6(cf, hport, addr) != NGX_OK) {
return NGX_ERROR;
}
break;
#endif
default: /* AF_INET */
if (ngx_http_add_addrs(cf, hport, addr) != NGX_OK) {
return NGX_ERROR;
}
break;
}
if (ngx_clone_listening(cf, ls) != NGX_OK) {
return NGX_ERROR;
}
addr++;
last--;
}
return NGX_OK;
}
2.6、ngx_http_add_listening
ngx_http_add_listening里面调用ngx_create_listening传入IP地址创建listen fd进行监听。
static ngx_listening_t *
ngx_http_add_listening(ngx_conf_t *cf, ngx_http_conf_addr_t *addr)
{
ngx_listening_t *ls;
ngx_http_core_loc_conf_t *clcf;
ngx_http_core_srv_conf_t *cscf;
ls = ngx_create_listening(cf, &addr->opt.sockaddr.sockaddr,
addr->opt.socklen);
if (ls == NULL) {
return NULL;
}
ls->addr_ntop = 1;
ls->handler = ngx_http_init_connection;
cscf = addr->default_server;
ls->pool_size = cscf->connection_pool_size;
ls->post_accept_timeout = cscf->client_header_timeout;
clcf = cscf->ctx->loc_conf[ngx_http_core_module.ctx_index];
ls->logp = clcf->error_log;
ls->log.data = &ls->addr_text;
ls->log.handler = ngx_accept_log_error;
#if (NGX_WIN32)
{
ngx_iocp_conf_t *iocpcf = NULL;
if (ngx_get_conf(cf->cycle->conf_ctx, ngx_events_module)) {
iocpcf = ngx_event_get_conf(cf->cycle->conf_ctx, ngx_iocp_module);
}
if (iocpcf && iocpcf->acceptex_read) {
ls->post_accept_buffer_size = cscf->client_header_buffer_size;
}
}
#endif
ls->backlog = addr->opt.backlog;
ls->rcvbuf = addr->opt.rcvbuf;
ls->sndbuf = addr->opt.sndbuf;
ls->keepalive = addr->opt.so_keepalive;
#if (NGX_HAVE_KEEPALIVE_TUNABLE)
ls->keepidle = addr->opt.tcp_keepidle;
ls->keepintvl = addr->opt.tcp_keepintvl;
ls->keepcnt = addr->opt.tcp_keepcnt;
#endif
#if (NGX_HAVE_DEFERRED_ACCEPT && defined SO_ACCEPTFILTER)
ls->accept_filter = addr->opt.accept_filter;
#endif
#if (NGX_HAVE_DEFERRED_ACCEPT && defined TCP_DEFER_ACCEPT)
ls->deferred_accept = addr->opt.deferred_accept;
#endif
#if (NGX_HAVE_INET6)
ls->ipv6only = addr->opt.ipv6only;
#endif
#if (NGX_HAVE_SETFIB)
ls->setfib = addr->opt.setfib;
#endif
#if (NGX_HAVE_TCP_FASTOPEN)
ls->fastopen = addr->opt.fastopen;
#endif
#if (NGX_HAVE_REUSEPORT)
ls->reuseport = addr->opt.reuseport;
#endif
return ls;
}
三、Nginx 启动http 状态的流程
http状态机描述定义（/src/http/ngx_http_core_module.h）：
typedef enum {
NGX_HTTP_POST_READ_PHASE = 0,
NGX_HTTP_SERVER_REWRITE_PHASE,
NGX_HTTP_FIND_CONFIG_PHASE,
NGX_HTTP_REWRITE_PHASE,
NGX_HTTP_POST_REWRITE_PHASE,
NGX_HTTP_PREACCESS_PHASE,
NGX_HTTP_ACCESS_PHASE,
NGX_HTTP_POST_ACCESS_PHASE,
NGX_HTTP_PRECONTENT_PHASE,
NGX_HTTP_CONTENT_PHASE,
NGX_HTTP_LOG_PHASE
} ngx_http_phases;
后言
本专栏知识点是通过<零声教育>的系统学习，进行梳理总结写下文章，对c/c++linux系统提升感兴趣的读者，可以点击链接,详细查看详细的服务:C/C++服务器课程
转载：https://blog.csdn.net/Long_xu/article/details/127961102
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