Nginx源码分析-全局变量cycle初始化
Nginx 启动过程中会调用 ngx_init_cycle 初始化一个全局变量 ngx_cycle, 这是 nginx 的一个核心结构体,类型为 ngx_cycle_t 。
结构体定义
ngx_cycle_t 结构体定义:
typedef struct ngx_cycle_s ngx_cycle_t;
struct ngx_cycle_s {
void ****conf_ctx; //各模块配置文件数组
ngx_pool_t *pool; //内存池
ngx_log_t *log; //日志指针
ngx_log_t new_log;
ngx_uint_t log_use_stderr; /* unsigned log_use_stderr:1; */
ngx_connection_t **files; //连接文件
ngx_connection_t *free_connections; //空闲连接
ngx_uint_t free_connection_n; //空闲连接个数
ngx_module_t **modules; //模块数组
ngx_uint_t modules_n; //模块个数
ngx_uint_t modules_used; /* unsigned modules_used:1; */
ngx_queue_t reusable_connections_queue;
ngx_uint_t reusable_connections_n;
time_t connections_reuse_time;
ngx_array_t listening; //监听数组
ngx_array_t paths; //路径数组
ngx_array_t config_dump; //配置拷贝
ngx_rbtree_t config_dump_rbtree; //配置拷贝红黑树
ngx_rbtree_node_t config_dump_sentinel; //红黑树哨兵结点
ngx_list_t open_files; //打工文件列表
ngx_list_t shared_memory; //共享内存列表
ngx_uint_t connection_n; //连接数数
ngx_uint_t files_n; //打开文件数
ngx_connection_t *connections; //连接事件
ngx_event_t *read_events; //读事件
ngx_event_t *write_events; //写事件
ngx_cycle_t *old_cycle; //旧的cycle
ngx_str_t conf_file; //配置文件
ngx_str_t conf_param; //配置参数
ngx_str_t conf_prefix; //配置文件前缀
ngx_str_t prefix; //前缀
ngx_str_t error_log; //错误日志
ngx_str_t lock_file; //锁文件
ngx_str_t hostname; //主机名
};
流程图
ngx_init_cycle 函数主流程图:
分步介绍
更新时区和时间
//更新时区
ngx_timezone_update();
/* force localtime update with a new timezone */
tp = ngx_timeofday();
tp->sec = 0;
//更新时间
ngx_time_update();
申请内存池
log = old_cycle->log;
//创建一个 16k的内存池
pool = ngx_create_pool(NGX_CYCLE_POOL_SIZE, log);
if (pool == NULL) {
return NULL;
}
pool->log = log;
申请一个 Cycle 并初始化
cycle = ngx_pcalloc(pool, sizeof(ngx_cycle_t));
if (cycle == NULL) {
ngx_destroy_pool(pool);
return NULL;
}
cycle->pool = pool;
cycle->log = log;
cycle->old_cycle = old_cycle;
cycle 内各元素初始化
包括配置前缀,错误日志路径,配置文件路径, 配置参数,path 数组,config_dump数组,config_dump_rbtree 红黑树,打开文件,共享内存,reusable_connections_queue 列表,监听文件,配置上下文及主机名。
//赋值配置前缀
cycle->conf_prefix.len = old_cycle->conf_prefix.len;
cycle->conf_prefix.data = ngx_pstrdup(pool, &old_cycle->conf_prefix);
if (cycle->conf_prefix.data == NULL) {
ngx_destroy_pool(pool);
return NULL;
}
cycle->prefix.len = old_cycle->prefix.len;
cycle->prefix.data = ngx_pstrdup(pool, &old_cycle->prefix);
if (cycle->prefix.data == NULL) {
ngx_destroy_pool(pool);
return NULL;
}
//赋值错误日志路径
cycle->error_log.len = old_cycle->error_log.len;
cycle->error_log.data = ngx_pnalloc(pool, old_cycle->error_log.len + 1);
if (cycle->error_log.data == NULL) {
ngx_destroy_pool(pool);
return NULL;
}
ngx_cpystrn(cycle->error_log.data, old_cycle->error_log.data,
old_cycle->error_log.len + 1);
//赋值配置文件路径
cycle->conf_file.len = old_cycle->conf_file.len;
cycle->conf_file.data = ngx_pnalloc(pool, old_cycle->conf_file.len + 1);
if (cycle->conf_file.data == NULL) {
ngx_destroy_pool(pool);
return NULL;
}
ngx_cpystrn(cycle->conf_file.data, old_cycle->conf_file.data,
old_cycle->conf_file.len + 1);
//赋值配置参数
cycle->conf_param.len = old_cycle->conf_param.len;
cycle->conf_param.data = ngx_pstrdup(pool, &old_cycle->conf_param);
if (cycle->conf_param.data == NULL) {
ngx_destroy_pool(pool);
return NULL;
}
//初始化paths数组
n = old_cycle->paths.nelts ? old_cycle->paths.nelts : 10;
if (ngx_array_init(&cycle->paths, pool, n, sizeof(ngx_path_t *))
!= NGX_OK)
{
ngx_destroy_pool(pool);
return NULL;
}
ngx_memzero(cycle->paths.elts, n * sizeof(ngx_path_t *));
//初始化config_dump数组
if (ngx_array_init(&cycle->config_dump, pool, 1, sizeof(ngx_conf_dump_t))
!= NGX_OK)
{
ngx_destroy_pool(pool);
return NULL;
}
//初始化 config_dump_rbtree 红黑树
ngx_rbtree_init(&cycle->config_dump_rbtree, &cycle->config_dump_sentinel,
ngx_str_rbtree_insert_value);
//计算打开文件数目
if (old_cycle->open_files.part.nelts) {
n = old_cycle->open_files.part.nelts;
for (part = old_cycle->open_files.part.next; part; part = part->next) {
n += part->nelts;
}
} else {
n = 20;
}
//打开文件链表初始化,??什么时候赋值
if (ngx_list_init(&cycle->open_files, pool, n, sizeof(ngx_open_file_t))
!= NGX_OK)
{
ngx_destroy_pool(pool);
return NULL;
}
//计算共享内存数目
if (old_cycle->shared_memory.part.nelts) {
n = old_cycle->shared_memory.part.nelts;
for (part = old_cycle->shared_memory.part.next; part; part = part->next)
{
n += part->nelts;
}
} else {
n = 1;
}
//初始化共享内存列表
if (ngx_list_init(&cycle->shared_memory, pool, n, sizeof(ngx_shm_zone_t))
!= NGX_OK)
{
ngx_destroy_pool(pool);
return NULL;
}
//初始化listening数组
n = old_cycle->listening.nelts ? old_cycle->listening.nelts : 10;
if (ngx_array_init(&cycle->listening, pool, n, sizeof(ngx_listening_t))
!= NGX_OK)
{
ngx_destroy_pool(pool);
return NULL;
}
ngx_memzero(cycle->listening.elts, n * sizeof(ngx_listening_t));
//初始化 reusable_connections_queue 列表
ngx_queue_init(&cycle->reusable_connections_queue);
//申请配置上下文内存,每个模块一个配置信息,以void*指针保存配置结构地址
cycle->conf_ctx = ngx_pcalloc(pool, ngx_max_module * sizeof(void *));
if (cycle->conf_ctx == NULL) {
ngx_destroy_pool(pool);
return NULL;
}
//获取主机名
if (gethostname(hostname, NGX_MAXHOSTNAMELEN) == -1) {
ngx_log_error(NGX_LOG_EMERG, log, ngx_errno, "gethostname() failed");
ngx_destroy_pool(pool);
return NULL;
}
/* on Linux gethostname() silently truncates name that does not fit */
hostname[NGX_MAXHOSTNAMELEN - 1] = '\0';
cycle->hostname.len = ngx_strlen(hostname);
cycle->hostname.data = ngx_pnalloc(pool, cycle->hostname.len);
if (cycle->hostname.data == NULL) {
ngx_destroy_pool(pool);
return NULL;
}
ngx_strlow(cycle->hostname.data, (u_char *) hostname, cycle->hostname.len);
初始化模块信息
//初始化 cycle 内的模块信息
if (ngx_cycle_modules(cycle) != NGX_OK) {
ngx_destroy_pool(pool);
return NULL;
}
//调用 create_conf 函数句柄来创建 NGX_CORE_MODULE 类型模块的配置
for (i = 0; cycle->modules[i]; i++) {
if (cycle->modules[i]->type != NGX_CORE_MODULE) {
continue;
}
module = cycle->modules[i]->ctx;
if (module->create_conf) {
rv = module->create_conf(cycle);
if (rv == NULL) {
ngx_destroy_pool(pool);
return NULL;
}
cycle->conf_ctx[cycle->modules[i]->index] = rv;
}
}
初始化配置解析结构
解析配置时会用到一个 ngx_conf_t 结构体,定义为:
typedef struct ngx_conf_s ngx_conf_t;
struct ngx_conf_s {
char *name;
ngx_array_t *args; //解析出的参数
ngx_cycle_t *cycle; //cycle
ngx_pool_t *pool; //内存池
ngx_pool_t *temp_pool; //临时内存池
ngx_conf_file_t *conf_file; //配置文件信息
ngx_log_t *log; //日志指针
void *ctx; //所有模块配置数组
ngx_uint_t module_type; //配置模块类型
ngx_uint_t cmd_type; //配置命令类型
ngx_conf_handler_pt handler;
void *handler_conf;
};
初始化过程:
//初始化配置解析结构
ngx_memzero(&conf, sizeof(ngx_conf_t));
/* STUB: init array ? */
//申请可带 10 个参数的数组,用于存储配置解析参数
conf.args = ngx_array_create(pool, 10, sizeof(ngx_str_t));
if (conf.args == NULL) {
ngx_destroy_pool(pool);
return NULL;
}
//申请一个临时内存池
conf.temp_pool = ngx_create_pool(NGX_CYCLE_POOL_SIZE, log);
if (conf.temp_pool == NULL) {
ngx_destroy_pool(pool);
return NULL;
}
//配置解析结构初始化,要解析的模块类型为 NGX_CORE_MODULE,命令类型为 NGX_MAIN_CONF
conf.ctx = cycle->conf_ctx;
conf.cycle = cycle;
conf.pool = pool;
conf.log = log;
conf.module_type = NGX_CORE_MODULE;
conf.cmd_type = NGX_MAIN_CONF;
解析配置
//解析命令行中的配置,里面通过调用 ngx_conf_parse 来实现配置的解析
if (ngx_conf_param(&conf) != NGX_CONF_OK) {
environ = senv;
ngx_destroy_cycle_pools(&conf);
return NULL;
}
//解析配置文件中的配置
if (ngx_conf_parse(&conf, &cycle->conf_file) != NGX_CONF_OK) {
environ = senv;
ngx_destroy_cycle_pools(&conf);
return NULL;
}
初始化各模块配置
//通过调用 init_conf 初始化函数句柄来初始化 NGX_CORE_MODULE 类型模块配置
for (i = 0; cycle->modules[i]; i++) {
if (cycle->modules[i]->type != NGX_CORE_MODULE) {
continue;
}
module = cycle->modules[i]->ctx;
if (module->init_conf) {
if (module->init_conf(cycle,
cycle->conf_ctx[cycle->modules[i]->index])
== NGX_CONF_ERROR)
{
environ = senv;
ngx_destroy_cycle_pools(&conf);
return NULL;
}
}
}
创建所需目录
//创建目录,一些配置中会存在目录的配置,在解析配置时添加进paths中,这里创建该目录
if (ngx_create_paths(cycle, ccf->user) != NGX_OK) {
goto failed;
}
创建并初始化共享内存
/* create shared memory */
//创建并初始化配置中需要的共享内存
part = &cycle->shared_memory.part;
shm_zone = part->elts;
for (i = 0; /* void */ ; i++) {
if (i >= part->nelts) {
if (part->next == NULL) {
break;
}
part = part->next;
shm_zone = part->elts;
i = 0;
}
if (shm_zone[i].shm.size == 0) {
ngx_log_error(NGX_LOG_EMERG, log, 0,
"zero size shared memory zone \"%V\"",
&shm_zone[i].shm.name);
goto failed;
}
shm_zone[i].shm.log = cycle->log;
opart = &old_cycle->shared_memory.part;
oshm_zone = opart->elts;
//查询原 old_cycle 中是否包含该共享内存,如果存在则直接将其复制过来
for (n = 0; /* void */ ; n++) {
if (n >= opart->nelts) {
if (opart->next == NULL) {
break;
}
opart = opart->next;
oshm_zone = opart->elts;
n = 0;
}
if (shm_zone[i].shm.name.len != oshm_zone[n].shm.name.len) {
continue;
}
if (ngx_strncmp(shm_zone[i].shm.name.data,
oshm_zone[n].shm.name.data,
shm_zone[i].shm.name.len)
!= 0)
{
continue;
}
if (shm_zone[i].tag == oshm_zone[n].tag
&& shm_zone[i].shm.size == oshm_zone[n].shm.size
&& !shm_zone[i].noreuse)
{
shm_zone[i].shm.addr = oshm_zone[n].shm.addr;
#if (NGX_WIN32)
shm_zone[i].shm.handle = oshm_zone[n].shm.handle;
#endif
if (shm_zone[i].init(&shm_zone[i], oshm_zone[n].data)
!= NGX_OK)
{
goto failed;
}
goto shm_zone_found;
}
break;
}
//申请并初始化该共享内存
if (ngx_shm_alloc(&shm_zone[i].shm) != NGX_OK) {
goto failed;
}
if (ngx_init_zone_pool(cycle, &shm_zone[i]) != NGX_OK) {
goto failed;
}
if (shm_zone[i].init(&shm_zone[i], NULL) != NGX_OK) {
goto failed;
}
shm_zone_found:
continue;
}
处理监听的 socket
/* handle the listening sockets */
//处理监听的sockets
if (old_cycle->listening.nelts) {
ls = old_cycle->listening.elts;
for (i = 0; i < old_cycle->listening.nelts; i++) {
ls[i].remain = 0;
}
nls = cycle->listening.elts;
for (n = 0; n < cycle->listening.nelts; n++) {
for (i = 0; i < old_cycle->listening.nelts; i++) {
if (ls[i].ignore) {
continue;
}
if (ls[i].remain) {
continue;
}
if (ls[i].type != nls[n].type) {
continue;
}
if (ngx_cmp_sockaddr(nls[n].sockaddr, nls[n].socklen,
ls[i].sockaddr, ls[i].socklen, 1)
== NGX_OK)
{
nls[n].fd = ls[i].fd;
nls[n].inherited = ls[i].inherited;
nls[n].previous = &ls[i];
ls[i].remain = 1;
if (ls[i].backlog != nls[n].backlog) {
nls[n].listen = 1;
}
#if (NGX_HAVE_DEFERRED_ACCEPT && defined SO_ACCEPTFILTER)
/*
* FreeBSD, except the most recent versions,
* could not remove accept filter
*/
nls[n].deferred_accept = ls[i].deferred_accept;
if (ls[i].accept_filter && nls[n].accept_filter) {
if (ngx_strcmp(ls[i].accept_filter,
nls[n].accept_filter)
!= 0)
{
nls[n].delete_deferred = 1;
nls[n].add_deferred = 1;
}
} else if (ls[i].accept_filter) {
nls[n].delete_deferred = 1;
} else if (nls[n].accept_filter) {
nls[n].add_deferred = 1;
}
#endif
#if (NGX_HAVE_DEFERRED_ACCEPT && defined TCP_DEFER_ACCEPT)
if (ls[i].deferred_accept && !nls[n].deferred_accept) {
nls[n].delete_deferred = 1;
} else if (ls[i].deferred_accept != nls[n].deferred_accept)
{
nls[n].add_deferred = 1;
}
#endif
#if (NGX_HAVE_REUSEPORT)
if (nls[n].reuseport && !ls[i].reuseport) {
nls[n].add_reuseport = 1;
}
#endif
break;
}
}
if (nls[n].fd == (ngx_socket_t) -1) {
nls[n].open = 1;
#if (NGX_HAVE_DEFERRED_ACCEPT && defined SO_ACCEPTFILTER)
if (nls[n].accept_filter) {
nls[n].add_deferred = 1;
}
#endif
#if (NGX_HAVE_DEFERRED_ACCEPT && defined TCP_DEFER_ACCEPT)
if (nls[n].deferred_accept) {
nls[n].add_deferred = 1;
}
#endif
}
}
} else {
ls = cycle->listening.elts;
for (i = 0; i < cycle->listening.nelts; i++) {
ls[i].open = 1;
#if (NGX_HAVE_DEFERRED_ACCEPT && defined SO_ACCEPTFILTER)
if (ls[i].accept_filter) {
ls[i].add_deferred = 1;
}
#endif
#if (NGX_HAVE_DEFERRED_ACCEPT && defined TCP_DEFER_ACCEPT)
if (ls[i].deferred_accept) {
ls[i].add_deferred = 1;
}
#endif
}
}
if (ngx_open_listening_sockets(cycle) != NGX_OK) {
goto failed;
}
if (!ngx_test_config) {
ngx_configure_listening_sockets(cycle);
}
/* commit the new cycle configuration */
if (!ngx_use_stderr) {
(void) ngx_log_redirect_stderr(cycle);
}
pool->log = cycle->log;
//初始化所有模块
if (ngx_init_modules(cycle) != NGX_OK) {
/* fatal */
exit(1);
}
清理工作
清理工作包括释放不需要的共享内存,关闭不需要的 socket,关闭不需要的打开文件,销毁临时内存池。
//释放不需要的共享内存,遍历old_cycle->shared_memory,查找每个共享内存在 cycle->shared_memory中是否存在,不存在则直接释放
opart = &old_cycle->shared_memory.part;
oshm_zone = opart->elts;
for (i = 0; /* void */ ; i++) {
if (i >= opart->nelts) {
if (opart->next == NULL) {
goto old_shm_zone_done;
}
opart = opart->next;
oshm_zone = opart->elts;
i = 0;
}
part = &cycle->shared_memory.part;
shm_zone = part->elts;
for (n = 0; /* void */ ; n++) {
if (n >= part->nelts) {
if (part->next == NULL) {
break;
}
part = part->next;
shm_zone = part->elts;
n = 0;
}
if (oshm_zone[i].shm.name.len != shm_zone[n].shm.name.len) {
continue;
}
if (ngx_strncmp(oshm_zone[i].shm.name.data,
shm_zone[n].shm.name.data,
oshm_zone[i].shm.name.len)
!= 0)
{
continue;
}
if (oshm_zone[i].tag == shm_zone[n].tag
&& oshm_zone[i].shm.size == shm_zone[n].shm.size
&& !oshm_zone[i].noreuse)
{
goto live_shm_zone;
}
break;
}
ngx_shm_free(&oshm_zone[i].shm);
live_shm_zone:
continue;
}
old_shm_zone_done:
/* close the unnecessary listening sockets */
//关闭不需要监听的sockets
ls = old_cycle->listening.elts;
for (i = 0; i < old_cycle->listening.nelts; i++) {
if (ls[i].remain || ls[i].fd == (ngx_socket_t) -1) {
continue;
}
if (ngx_close_socket(ls[i].fd) == -1) {
ngx_log_error(NGX_LOG_EMERG, log, ngx_socket_errno,
ngx_close_socket_n " listening socket on %V failed",
&ls[i].addr_text);
}
#if (NGX_HAVE_UNIX_DOMAIN)
if (ls[i].sockaddr->sa_family == AF_UNIX) {
u_char *name;
name = ls[i].addr_text.data + sizeof("unix:") - 1;
ngx_log_error(NGX_LOG_WARN, cycle->log, 0,
"deleting socket %s", name);
if (ngx_delete_file(name) == NGX_FILE_ERROR) {
ngx_log_error(NGX_LOG_EMERG, cycle->log, ngx_socket_errno,
ngx_delete_file_n " %s failed", name);
}
}
#endif
}
/* close the unnecessary open files */
//关闭不需要的打开文件
part = &old_cycle->open_files.part;
file = part->elts;
for (i = 0; /* void */ ; i++) {
if (i >= part->nelts) {
if (part->next == NULL) {
break;
}
part = part->next;
file = part->elts;
i = 0;
}
if (file[i].fd == NGX_INVALID_FILE || file[i].fd == ngx_stderr) {
continue;
}
if (ngx_close_file(file[i].fd) == NGX_FILE_ERROR) {
ngx_log_error(NGX_LOG_EMERG, log, ngx_errno,
ngx_close_file_n " \"%s\" failed",
file[i].name.data);
}
}
//销毁临时内存池
ngx_destroy_pool(conf.temp_pool);
nginx源码基于nginx-1.22.0版本
参考:
Nginx 启动初始化过程
Nginx源码分析 - 主流程篇 - 全局变量cycle初始化(11)
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