目录
一、数据结构
1. ngx_cycle_t的数据结构
2. ngx_core_conf_t的数据结构
二、初始化过程
1. 创建一个内存池。
2. 拷贝配置文件的路径前缀(/usr/local/nginx)
3. Nginx的路径前缀拷贝
4. 拷贝配置文件信息
5. 拷贝配置参数信息
6. 路径信息初始化
7. 初始化打开的文件句柄
8. 初始化shared_memory链表
9. 初始化listening数组
10. 模块创建和核心配置结构初始化ngx_core_conf_t
11. 配置文件nginx.conf解析
12. 创建PID文件
13. 遍历cycle->open_files链表中的文件,并且打开
14. 创建共享内存并初始化
15. 处理listening数组,并开始监听socket
16. 关闭或删除残留在old_cycle中的资源
Nginx的大部分初始化工作主要围绕一个类型为ngx_cycle_t类型的全局变量(cycle)展开。本文主要讲解cycle的数据结构以及初始化过程中干了什么事情。
cycle的初始化过程在/src/core/cycle.c文件中。
在使用gdb调试nginx源码时,需要设置启动变量
set args -c /usr/local/nginx/conf/nginx.conf
在上图中完成了配置文件
一、数据结构
1. ngx_cycle_t的数据结构
cycle是Nginx贯穿全局的一个全局变量。阅读Nginx的源码必须得先搞清楚cycle全局变量的初始化过程。
// nginx核心数据结构,表示nginx的生命周期,含有许多重要参数//// conf_ctx, 存储所有模块的配置结构体,是个二维数组// free_connections,空闲连接,使用指针串成单向链表// listening,监听的端口数组// connections/read_events/write_events,连接池,大小是connection_n//// 启动nginx时的环境参数,配置文件,工作路径等// 每个进程都有这个结构struct ngx_cycle_s {// 存储所有模块的配置结构体,是个二维数组// 0 = ngx_core_module 1 = ngx_errlog_module// 3 = ngx_event_module 4 = ngx_event_core_module// 5 = ngx_epoll_module 7 = ngx_http_module 8 = ngx_http_core_modulevoid ****conf_ctx;ngx_pool_t*pool;// 内存池// old_cycle的log对象ngx_log_t*log;// 使用error_log指令设置的新log对象ngx_log_t new_log;ngx_uint_tlog_use_stderr; /* unsigned log_use_stderr:1; */// 文件也当做连接来处理,也是读写操作// 如果使用epoll,那么这个指针通常是null,即不会使用ngx_connection_t **files;// 空闲连接,使用指针串成单向链表ngx_connection_t *free_connections;// 指向第一个空闲连接,即头节点ngx_uint_tfree_connection_n;// 空闲连接的数量// 1.10,保存模块数组,可以加载动态模块// 可以容纳所有的模块,大小是ngx_max_module + 1// ngx_cycle_modules()初始化ngx_module_t **modules;// 拷贝模块序号计数器到本cycle// ngx_cycle_modules()初始化ngx_uint_tmodules_n;// 标志位,cycle已经完成模块的初始化,不能再添加模块// 在ngx_load_module里检查,不允许加载动态模块ngx_uint_tmodules_used; /* unsigned modules_used:1; */ngx_queue_treusable_connections_queue;// 复用连接对象队列ngx_uint_treusable_connections_n;// 监听的端口数组, in ngx_connection.h // 主要成员: fd,backlog,rcvbuf,sndbufngx_array_tlistening;ngx_array_tpaths;// 打开的目录ngx_array_tconfig_dump; // dump config用ngx_rbtree_t config_dump_rbtree;ngx_rbtree_node_t config_dump_sentinel;// 打开的文件,主要是日志// 存储ngx_open_file_tngx_list_topen_files;// 共享内存ngx_list_tshared_memory;// 连接数组的数量// 由worker_connections指定,在event模块里设置ngx_uint_tconnection_n;ngx_uint_tfiles_n;// 连接池,大小是connection_n// 每个连接都有一个读事件和写事件,使用数组序号对应// 由ngx_event_core_module的ngx_event_process_init()创建ngx_connection_t *connections;// 读事件数组,大小与connections相同,并且一一对应// 由ngx_event_core_module的ngx_event_process_init()创建ngx_event_t *read_events;// 写事件数组,大小与connections相同,并且一一对应// 由ngx_event_core_module的ngx_event_process_init()创建ngx_event_t *write_events;// 保存之前的cycle,如init_cyclengx_cycle_t *old_cycle;// 启动nginx时的配置文件ngx_str_t conf_file;// 启动nginx时的-g参数ngx_str_t conf_param;// 如果使用了-p,那么conf_prefix==prefix// 否则两者是不同的,见ngx_process_options// #define NGX_CONF_PREFIX "conf/"// 即-c选项指定的配置文件目录ngx_str_t conf_prefix;// #define NGX_PREFIX "/usr/local/nginx/"// 即-p选项指定的工作目录ngx_str_t prefix;// 在linux里直接用共享内存实现锁,此成员无用ngx_str_t lock_file;// 当前主机的hostname// ngx_init_cycle()里初始化,全小写ngx_str_t hostname;};
全局变量指针指向该结构体,并使用volatile修饰
保存启动时的环境变量
给nginx的模块编号,仅仅是编号
将模块编号和名字转移到cycle->modules数组中
可以看出0和1是NGX_CORE_MODULE 模块,会执行相应的create_conf函数
会执行上面的ngx_core_module_create_conf函数,将从内存中分配 并存储到
至此完成了 配置文件中worker_processes 解析以及赋值操作
2. ngx_core_conf_t的数据结构
ngx_code_conf_t的数据结构主要用于装在Nginx的nginx.conf的核心配置文件的参数。后面我们会具体讲解配置文件nginx.conf的解析过程以及和模块。
/*** 核心配置文件信息* 对应nginx.conf的* #user nobody;worker_processes 1;#error_log logs/error.log;#error_log logs/error.log notice;#error_log logs/error.log info;#pid logs/nginx.pid;*/typedef struct {ngx_flag_tdaemon;ngx_flag_tmaster;ngx_msec_ttimer_resolution;ngx_int_t worker_processes;ngx_int_t debug_points;ngx_int_t rlimit_nofile;off_t rlimit_core;int priority;ngx_uint_tcpu_affinity_auto;ngx_uint_tcpu_affinity_n;ngx_cpuset_t *cpu_affinity;char *username;ngx_uid_t user;ngx_gid_t group;ngx_str_t working_directory;ngx_str_t lock_file;ngx_str_t pid;ngx_str_t oldpid;ngx_array_tenv;char**environment;} ngx_core_conf_t;
二、初始化过程
1. 创建一个内存池。
后续所有的内存都会被分配到这个内存池上面。
/* 创建一块内存 */pool = ngx_create_pool(NGX_CYCLE_POOL_SIZE, log);if (pool == NULL) {return NULL;}pool->log = log;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;
2. 拷贝配置文件的路径前缀(/usr/local/nginx)
主要拷贝到 cycle->conf_prefix
/* 配置文件路径拷贝 /usr/local/nginx/ */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;}
3. Nginx的路径前缀拷贝
拷贝到cycle->prefix
/* Nginx路径拷贝 */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;}
4. 拷贝配置文件信息
/nginx/conf/nginx.conf 文件路径
/* 配置文件 信息拷贝*/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);
5. 拷贝配置参数信息
/* 配置参数 信息拷贝 */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;}
6. 路径信息初始化
/* 路径信息 */n = old_cycle->paths.nelts ? old_cycle->paths.nelts : 10;cycle->paths.elts = ngx_pcalloc(pool, n * sizeof(ngx_path_t *));if (cycle->paths.elts == NULL) {ngx_destroy_pool(pool);return NULL;}cycle->paths.nelts = 0;cycle->paths.size = sizeof(ngx_path_t *);cycle->paths.nalloc = n;cycle->paths.pool = pool;if (ngx_array_init(&cycle->config_dump, pool, 1, sizeof(ngx_conf_dump_t))!= NGX_OK){ngx_destroy_pool(pool);return NULL;}
7. 初始化打开的文件句柄
/* 初始化打开的文件句柄 */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;}if (ngx_list_init(&cycle->open_files, pool, n, sizeof(ngx_open_file_t))!= NGX_OK){ngx_destroy_pool(pool);return NULL;}
8. 初始化shared_memory链表
/* 初始化shared_memory链表 */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;}if (ngx_list_init(&cycle->shared_memory, pool, n, sizeof(ngx_shm_zone_t))!= NGX_OK){ngx_destroy_pool(pool);return NULL;}
9. 初始化listening数组
/* 初始化listening */n = old_cycle->listening.nelts ? old_cycle->listening.nelts : 10;cycle->listening.elts = ngx_pcalloc(pool, n * sizeof(ngx_listening_t));if (cycle->listening.elts == NULL) {ngx_destroy_pool(pool);return NULL;}cycle->listening.nelts = 0;cycle->listening.size = sizeof(ngx_listening_t);cycle->listening.nalloc = n;cycle->listening.pool = pool;
10. 模块创建和核心配置结构初始化ngx_core_conf_t
主要初始化cycle->modules创建核心配置结构,Nginx的核心配置会放到ngx_core_conf_t *ccf数据结构上初始化核心配置结构ngx_core_conf_t */* 创建模块以及创建模块的配置信息 */if (ngx_cycle_modules(cycle) != NGX_OK) {ngx_destroy_pool(pool);return NULL;}/** 核心模块的配置文件创建* 配置创建调用nginx.c 中的 ngx_core_module_create_conf* */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); //模块回调函数,创建模块的配置信息if (rv == NULL) {ngx_destroy_pool(pool);return NULL;}cycle->conf_ctx[cycle->modules[i]->index] = rv; //配置文件复制}}
/* 获取核心配置文件的数据结构 ngx_core_conf_t */ccf = (ngx_core_conf_t *) ngx_get_conf(cycle->conf_ctx, ngx_core_module);
11. 配置文件nginx.conf解析
配置文件解析会在下章中详细解读。
/* 解析配置文件 */ngx_memzero(&conf, sizeof(ngx_conf_t));/* STUB: init array ? */conf.args = ngx_array_create(pool, 10, sizeof(ngx_str_t));if (conf.args == NULL) {ngx_destroy_pool(pool);return NULL;}/* 创建一个临时的内存池,后面会清空掉;conf也主要用于解析配置文件的临时变量 */conf.temp_pool = ngx_create_pool(NGX_CYCLE_POOL_SIZE, log);if (conf.temp_pool == NULL) {ngx_destroy_pool(pool);return NULL;}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;#if 0log->log_level = NGX_LOG_DEBUG_ALL;#endif/* 解析命令行中的配置参数;例如:nginx -t -c /usr/local/nginx/conf/nginx.conf */if (ngx_conf_param(&conf) != NGX_CONF_OK) {environ = senv;ngx_destroy_cycle_pools(&conf);return NULL;}/* 解析配置文件/usr/local/nginx/conf/nginx.conf 信息 */if (ngx_conf_parse(&conf, &cycle->conf_file) != NGX_CONF_OK) {environ = senv;ngx_destroy_cycle_pools(&conf);return NULL;}if (ngx_test_config && !ngx_quiet_mode) {ngx_log_stderr(0, "the configuration file %s syntax is ok",cycle->conf_file.data);}
12. 创建PID文件
Nginx将PID写入文件内,/usr/local/nginx-1.4.7/nginx.pid,后续对Nginx进行重启、停止、信号操作就可以使用这个PID了。
/* 创建pid文件,/usr/local/nginx-1.4.7/nginx.pid*/if (ngx_test_config) {if (ngx_create_pidfile(&ccf->pid, log) != NGX_OK) {goto failed;}} else if (!ngx_is_init_cycle(old_cycle)) {/** we do not create the pid file in the first ngx_init_cycle() call* because we need to write the demonized process pid*/old_ccf = (ngx_core_conf_t *) ngx_get_conf(old_cycle->conf_ctx,ngx_core_module);if (ccf->pid.len != old_ccf->pid.len|| ngx_strcmp(ccf->pid.data, old_ccf->pid.data) != 0){/* new pid file name */if (ngx_create_pidfile(&ccf->pid, log) != NGX_OK) {goto failed;}ngx_delete_pidfile(old_cycle);}}
13. 遍历cycle->open_files链表中的文件,并且打开
cycle->open_file主要是在ngx_conf_open_file这个方法里面放入文件路径,然后下面去打开文件。
主要是日志文件和配置文件。
/* 打开日志,并调用ngx_conf_open_file方法,会将打开的文件放到cycle->open_files链表中 主要是日志文件和配置文件*/if (ngx_log_open_default(cycle) != NGX_OK) {goto failed;}
/* 遍历cycle->open_files链表中的文件,并打开 */part = &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].name.len == 0) {continue;}file[i].fd = ngx_open_file(file[i].name.data,NGX_FILE_APPEND,NGX_FILE_CREATE_OR_OPEN,NGX_FILE_DEFAULT_ACCESS);ngx_log_debug3(NGX_LOG_DEBUG_CORE, log, 0,"log: %p %d \"%s\"",&file[i], file[i].fd, file[i].name.data);if (file[i].fd == NGX_INVALID_FILE) {ngx_log_error(NGX_LOG_EMERG, log, ngx_errno,ngx_open_file_n " \"%s\" failed",file[i].name.data);goto failed;}#if !(NGX_WIN32)if (fcntl(file[i].fd, F_SETFD, FD_CLOEXEC) == -1) {ngx_log_error(NGX_LOG_EMERG, log, ngx_errno,"fcntl(FD_CLOEXEC) \"%s\" failed",file[i].name.data);goto failed;}#endif}
14. 创建共享内存并初始化
新旧shared_memory链表的比较,相同的共享内存保留,旧的不同的共享内存被释放,新的被创建
/* 创建共享内存并初始化 */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;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;#endifif (shm_zone[i].init(&shm_zone[i], oshm_zone[n].data)!= NGX_OK){goto failed;}goto shm_zone_found;}ngx_shm_free(&oshm_zone[n].shm);break;}
15. 处理listening数组,并开始监听socket
/* handle the listening sockets *//* 处理listening数组,并开始监听socket */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].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;}#endifbreak;}}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);}
16. 关闭或删除残留在old_cycle中的资源
释放多余的共享内存;关闭多余的侦听sockets;关闭多余的打开文件/* close and delete stuff that lefts from an old cycle *//* free the unnecessary shared memory *//* 关闭或删除残留在old_cycle中的资源 释放多余的共享内存;关闭多余的侦听sockets;关闭多余的打开文件*/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&& ngx_strncmp(oshm_zone[i].shm.name.data,shm_zone[n].shm.name.data,oshm_zone[i].shm.name.len)== 0){goto live_shm_zone;}}ngx_shm_free(&oshm_zone[i].shm);
参考地址:
1.https://initphp./article/details/51882804
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