nginx作为高效的http服务器和反向代理服务器，值得我们深入了解。
我们带着几个问题，深入了解下nginx的工作原理。首先是开篇：nginx是如何启动的？
nginx是用c写的软件，github地址: https://github.com/nginx/nginx
其目录结构如下，我们主要关注 src 目录下的文件。
nginx.c 是main函数入口，我们也是通过这里进行启动流程分析的。
零、启动流程时序图
我们先通过一个时序图进行全局观察nginx是如何跑起来的，然后后续再稍微深入了解些细节。
简要步骤说明：
1. 初始化调试信息;
2. 解析命令配置参数信息;
3. 初始化环境信息，时间、pid、ssl...;
4. 初始化 init_cycle 变量, 将各种配置信息放入其中;
5. 处理继承NGINX环境变量中指定的socket;
6. 给各处理模块编号;
7. 初始化全局变量 ngx_cycle, 将init_cycle信息转移过来，并处理许多其他必要信息;
8. 初始化信号控制处理器 signals;
9. 开启worker子进程循环服务，开启master主进程循环服务;
一、main函数启动处理实现
通过main函数呢，也就完全理解了整个过程了，整个运行框架都在这里了。细节看需要进行深入。
// src/core/nginx.c 入口 int ngx_cdecl main(int argc, char *const *argv) { ngx_buf_t *b; ngx_log_t *log; ngx_uint_t i; ngx_cycle_t *cycle, init_cycle; ngx_conf_dump_t *cd; ngx_core_conf_t *ccf; ngx_debug_init(); // 初始化错误信息容器 if (ngx_strerror_init() != NGX_OK) { return 1; } // 解析命令行参数，有限参数 if (ngx_get_options(argc, argv) != NGX_OK) { return 1; } if (ngx_show_version) { ngx_show_version_info(); if (!ngx_test_config) { return 0; } } /* TODO */ ngx_max_sockets = -1; ngx_time_init(); #if (NGX_PCRE) ngx_regex_init(); #endif ngx_pid = ngx_getpid(); ngx_parent = ngx_getppid(); // 初始化日志文件实例 log = ngx_log_init(ngx_prefix); if (log == NULL) { return 1; } /* STUB */ #if (NGX_OPENSSL) ngx_ssl_init(log); #endif /* * init_cycle->log is required for signal handlers and * ngx_process_options() */ ngx_memzero(&init_cycle, sizeof(ngx_cycle_t)); init_cycle.log = log; // 将 ngx_cycle 和 init_cycle 指向同一块内存，以下对 init_cycle 的操作，也就是对 ngx_cycle的操作 ngx_cycle = &init_cycle; init_cycle.pool = ngx_create_pool(1024, log); if (init_cycle.pool == NULL) { return 1; } // 保存命令行参数信息 if (ngx_save_argv(&init_cycle, argc, argv) != NGX_OK) { return 1; } // 设置进程相关信息，如配置文件，日志级别，配置前缀等 if (ngx_process_options(&init_cycle) != NGX_OK) { return 1; } // 初始化操作系统相关的参数, 如 cpu 核数, 进程标题，页缓存大小，随机数等 if (ngx_os_init(log) != NGX_OK) { return 1; } /* * ngx_crc32_table_init() requires ngx_cacheline_size set in ngx_os_init() */ // crc32 表初始化，内存分配 if (ngx_crc32_table_init() != NGX_OK) { return 1; } /* * ngx_slab_sizes_init() requires ngx_pagesize set in ngx_os_init() */ // slat 大小设置初始化 ngx_slab_sizes_init(); // 添加继承过来的socket, 用于无中断重启 if (ngx_add_inherited_sockets(&init_cycle) != NGX_OK) { return 1; } // 设置 ngx_module 的索引值及名称 if (ngx_preinit_modules() != NGX_OK) { return 1; } // 初始化 cycle 相关必须信息，如初始化各模块（重量级方法） cycle = ngx_init_cycle(&init_cycle); if (cycle == NULL) { if (ngx_test_config) { ngx_log_stderr(0, "configuration file %s test failed", init_cycle.conf_file.data); } return 1; } // 测试结束 if (ngx_test_config) { if (!ngx_quiet_mode) { ngx_log_stderr(0, "configuration file %s test is successful", cycle->conf_file.data); } if (ngx_dump_config) { cd = cycle->config_dump.elts; for (i = 0; i < cycle->config_dump.nelts; i++) { ngx_write_stdout("# configuration file "); (void) ngx_write_fd(ngx_stdout, cd[i].name.data, cd[i].name.len); ngx_write_stdout(":" NGX_LINEFEED); b = cd[i].buffer; (void) ngx_write_fd(ngx_stdout, b->pos, b->last - b->pos); ngx_write_stdout(NGX_LINEFEED); } } return 0; } // 如果是进行启停控制，则处理信号即可 if (ngx_signal) { return ngx_signal_process(cycle, ngx_signal); } // 记录操作系统信息 // 日志级别先后: error > warn > notice > info > debug ngx_os_status(cycle->log); ngx_cycle = cycle; ccf = (ngx_core_conf_t *) ngx_get_conf(cycle->conf_ctx, ngx_core_module); if (ccf->master && ngx_process == NGX_PROCESS_SINGLE) { ngx_process = NGX_PROCESS_MASTER; } #if !(NGX_WIN32) // 初始化信号处理方法，针对 signals[] 中的方法进行调用注册 if (ngx_init_signals(cycle->log) != NGX_OK) { return 1; } if (!ngx_inherited && ccf->daemon) { // 如果使用后台进程运行，则 fork() 当前进程后退出 if (ngx_daemon(cycle->log) != NGX_OK) { return 1; } ngx_daemonized = 1; } if (ngx_inherited) { ngx_daemonized = 1; } #endif // 创建进程pid文件,写入 ngx_pid if (ngx_create_pidfile(&ccf->pid, cycle->log) != NGX_OK) { return 1; } if (ngx_log_redirect_stderr(cycle) != NGX_OK) { return 1; } if (log->file->fd != ngx_stderr) { if (ngx_close_file(log->file->fd) == NGX_FILE_ERROR) { ngx_log_error(NGX_LOG_ALERT, cycle->log, ngx_errno, ngx_close_file_n " built-in log failed"); } } ngx_use_stderr = 0; if (ngx_process == NGX_PROCESS_SINGLE) { ngx_single_process_cycle(cycle); } else { ngx_master_process_cycle(cycle); } return 0; }
二、命令行参数解析
解析命令行参数，让用户可以方便更改配置和控制nginx。没有啥复杂的，就是纯粹地按分割符将参数解析出来，放入全局的变量里，备后续的代码使用。简单看看即可。
// 解析命令行参数， -? -h -v -V -t -T -q -p -s static ngx_int_t ngx_get_options(int argc, char *const *argv) { u_char *p; ngx_int_t i; for (i = 1; i < argc; i++) { p = (u_char *) argv[i]; if (*p++ != '-') { ngx_log_stderr(0, "invalid option: "%s"", argv[i]); return NGX_ERROR; } while (*p) { switch (*p++) { // -h -v -V -t -T -q 后面无参数 case '?': case 'h': ngx_show_version = 1; ngx_show_help = 1; break; case 'v': ngx_show_version = 1; break; case 'V': ngx_show_version = 1; ngx_show_configure = 1; break; case 't': ngx_test_config = 1; break; case 'T': ngx_test_config = 1; ngx_dump_config = 1; break; case 'q': ngx_quiet_mode = 1; break; // -p -c -g -s 后面必带参数 case 'p': if (*p) { ngx_prefix = p; goto next; } if (argv[++i]) { ngx_prefix = (u_char *) argv[i]; goto next; } ngx_log_stderr(0, "option "-p" requires directory name"); return NGX_ERROR; // -c 指定配置文件 case 'c': if (*p) { ngx_conf_file = p; goto next; } if (argv[++i]) { ngx_conf_file = (u_char *) argv[i]; goto next; } ngx_log_stderr(0, "option "-c" requires file name"); return NGX_ERROR; case 'g': if (*p) { ngx_conf_params = p; goto next; } if (argv[++i]) { ngx_conf_params = (u_char *) argv[i]; goto next; } ngx_log_stderr(0, "option "-g" requires parameter"); return NGX_ERROR; // -s 服务启停控制 case 's': if (*p) { ngx_signal = (char *) p; } else if (argv[++i]) { ngx_signal = argv[i]; } else { ngx_log_stderr(0, "option "-s" requires parameter"); return NGX_ERROR; } if (ngx_strcmp(ngx_signal, "stop") == 0 || ngx_strcmp(ngx_signal, "quit") == 0 || ngx_strcmp(ngx_signal, "reopen") == 0 || ngx_strcmp(ngx_signal, "reload") == 0) { ngx_process = NGX_PROCESS_SIGNALLER; goto next; } ngx_log_stderr(0, "invalid option: "-s %s"", ngx_signal); return NGX_ERROR; default: ngx_log_stderr(0, "invalid option: "%c"", *(p - 1)); return NGX_ERROR; } } next: continue; } return NGX_OK; }
三、继承socket信息
通过 NGINX 这个环境变量，可以获取到原来的nginx监听的socket信息，如果要进行优雅重启，那么把这些socket接管过来，继续处理即可实现无中断重启服务作用。
// nginx.c, 继承之前的socket信息，无中断式重启 static ngx_int_t ngx_add_inherited_sockets(ngx_cycle_t *cycle) { u_char *p, *v, *inherited; ngx_int_t s; ngx_listening_t *ls; inherited = (u_char *) getenv(NGINX_VAR); if (inherited == NULL) { return NGX_OK; } ngx_log_error(NGX_LOG_NOTICE, cycle->log, 0, "using inherited sockets from "%s"", inherited); if (ngx_array_init(&cycle->listening, cycle->pool, 10, sizeof(ngx_listening_t)) != NGX_OK) { return NGX_ERROR; } for (p = inherited, v = p; *p; p++) { if (*p == ':' || *p == ';') { s = ngx_atoi(v, p - v); if (s == NGX_ERROR) { ngx_log_error(NGX_LOG_EMERG, cycle->log, 0, "invalid socket number "%s" in " NGINX_VAR " environment variable, ignoring the rest" " of the variable", v); break; } v = p + 1; // 添加到nginx的监听列表中 ls = ngx_array_push(&cycle->listening); if (ls == NULL) { return NGX_ERROR; } ngx_memzero(ls, sizeof(ngx_listening_t)); ls->fd = (ngx_socket_t) s; } } if (v != p) { ngx_log_error(NGX_LOG_EMERG, cycle->log, 0, "invalid socket number "%s" in " NGINX_VAR " environment variable, ignoring", v); } ngx_inherited = 1; // 设置每个socket的详细配置信息，比如忽略无效的socket等等 return ngx_set_inherited_sockets(cycle); }
// core/ngx_connection.c ngx_int_t ngx_set_inherited_sockets(ngx_cycle_t *cycle) { size_t len; ngx_uint_t i; ngx_listening_t *ls; socklen_t olen; #if (NGX_HAVE_DEFERRED_ACCEPT || NGX_HAVE_TCP_FASTOPEN) ngx_err_t err; #endif #if (NGX_HAVE_DEFERRED_ACCEPT && defined SO_ACCEPTFILTER) struct accept_filter_arg af; #endif #if (NGX_HAVE_DEFERRED_ACCEPT && defined TCP_DEFER_ACCEPT) int timeout; #endif #if (NGX_HAVE_REUSEPORT) int reuseport; #endif ls = cycle->listening.elts; for (i = 0; i < cycle->listening.nelts; i++) { ls[i].sockaddr = ngx_palloc(cycle->pool, sizeof(ngx_sockaddr_t)); if (ls[i].sockaddr == NULL) { return NGX_ERROR; } ls[i].socklen = sizeof(ngx_sockaddr_t); // 忽略无效的监听 if (getsockname(ls[i].fd, ls[i].sockaddr, &ls[i].socklen) == -1) { ngx_log_error(NGX_LOG_CRIT, cycle->log, ngx_socket_errno, "getsockname() of the inherited " "socket #%d failed", ls[i].fd); ls[i].ignore = 1; continue; } if (ls[i].socklen > (socklen_t) sizeof(ngx_sockaddr_t)) { ls[i].socklen = sizeof(ngx_sockaddr_t); } switch (ls[i].sockaddr->sa_family) { #if (NGX_HAVE_INET6) case AF_INET6: ls[i].addr_text_max_len = NGX_INET6_ADDRSTRLEN; len = NGX_INET6_ADDRSTRLEN + sizeof("[]:65535") - 1; break; #endif #if (NGX_HAVE_UNIX_DOMAIN) case AF_UNIX: ls[i].addr_text_max_len = NGX_UNIX_ADDRSTRLEN; len = NGX_UNIX_ADDRSTRLEN; break; #endif case AF_INET: ls[i].addr_text_max_len = NGX_INET_ADDRSTRLEN; len = NGX_INET_ADDRSTRLEN + sizeof(":65535") - 1; break; default: ngx_log_error(NGX_LOG_CRIT, cycle->log, ngx_socket_errno, "the inherited socket #%d has " "an unsupported protocol family", ls[i].fd); ls[i].ignore = 1; continue; } ls[i].addr_text.data = ngx_pnalloc(cycle->pool, len); if (ls[i].addr_text.data == NULL) { return NGX_ERROR; } len = ngx_sock_ntop(ls[i].sockaddr, ls[i].socklen, ls[i].addr_text.data, len, 1); if (len == 0) { return NGX_ERROR; } ls[i].addr_text.len = len; ls[i].backlog = NGX_LISTEN_BACKLOG; olen = sizeof(int); if (getsockopt(ls[i].fd, SOL_SOCKET, SO_TYPE, (void *) &ls[i].type, &olen) == -1) { ngx_log_error(NGX_LOG_CRIT, cycle->log, ngx_socket_errno, "getsockopt(SO_TYPE) %V failed", &ls[i].addr_text); ls[i].ignore = 1; continue; } olen = sizeof(int); if (getsockopt(ls[i].fd, SOL_SOCKET, SO_RCVBUF, (void *) &ls[i].rcvbuf, &olen) == -1) { ngx_log_error(NGX_LOG_ALERT, cycle->log, ngx_socket_errno, "getsockopt(SO_RCVBUF) %V failed, ignored", &ls[i].addr_text); ls[i].rcvbuf = -1; } olen = sizeof(int); if (getsockopt(ls[i].fd, SOL_SOCKET, SO_SNDBUF, (void *) &ls[i].sndbuf, &olen) == -1) { ngx_log_error(NGX_LOG_ALERT, cycle->log, ngx_socket_errno, "getsockopt(SO_SNDBUF) %V failed, ignored", &ls[i].addr_text); ls[i].sndbuf = -1; } #if 0 /* SO_SETFIB is currently a set only option */ #if (NGX_HAVE_SETFIB) olen = sizeof(int); if (getsockopt(ls[i].fd, SOL_SOCKET, SO_SETFIB, (void *) &ls[i].setfib, &olen) == -1) { ngx_log_error(NGX_LOG_ALERT, cycle->log, ngx_socket_errno, "getsockopt(SO_SETFIB) %V failed, ignored", &ls[i].addr_text); ls[i].setfib = -1; } #endif #endif #if (NGX_HAVE_REUSEPORT) reuseport = 0; olen = sizeof(int); #ifdef SO_REUSEPORT_LB if (getsockopt(ls[i].fd, SOL_SOCKET, SO_REUSEPORT_LB, (void *) &reuseport, &olen) == -1) { ngx_log_error(NGX_LOG_ALERT, cycle->log, ngx_socket_errno, "getsockopt(SO_REUSEPORT_LB) %V failed, ignored", &ls[i].addr_text); } else { ls[i].reuseport = reuseport ? 1 : 0; } #else if (getsockopt(ls[i].fd, SOL_SOCKET, SO_REUSEPORT, (void *) &reuseport, &olen) == -1) { ngx_log_error(NGX_LOG_ALERT, cycle->log, ngx_socket_errno, "getsockopt(SO_REUSEPORT) %V failed, ignored", &ls[i].addr_text); } else { ls[i].reuseport = reuseport ? 1 : 0; } #endif #endif if (ls[i].type != SOCK_STREAM) { continue; } #if (NGX_HAVE_TCP_FASTOPEN) olen = sizeof(int); if (getsockopt(ls[i].fd, IPPROTO_TCP, TCP_FASTOPEN, (void *) &ls[i].fastopen, &olen) == -1) { err = ngx_socket_errno; if (err != NGX_EOPNOTSUPP && err != NGX_ENOPROTOOPT && err != NGX_EINVAL) { ngx_log_error(NGX_LOG_NOTICE, cycle->log, err, "getsockopt(TCP_FASTOPEN) %V failed, ignored", &ls[i].addr_text); } ls[i].fastopen = -1; } #endif #if (NGX_HAVE_DEFERRED_ACCEPT && defined SO_ACCEPTFILTER) ngx_memzero(&af, sizeof(struct accept_filter_arg)); olen = sizeof(struct accept_filter_arg); if (getsockopt(ls[i].fd, SOL_SOCKET, SO_ACCEPTFILTER, &af, &olen) == -1) { err = ngx_socket_errno; if (err == NGX_EINVAL) { continue; } ngx_log_error(NGX_LOG_NOTICE, cycle->log, err, "getsockopt(SO_ACCEPTFILTER) for %V failed, ignored", &ls[i].addr_text); continue; } if (olen < sizeof(struct accept_filter_arg) || af.af_name[0] == ' ') { continue; } ls[i].accept_filter = ngx_palloc(cycle->pool, 16); if (ls[i].accept_filter == NULL) { return NGX_ERROR; } (void) ngx_cpystrn((u_char *) ls[i].accept_filter, (u_char *) af.af_name, 16); #endif #if (NGX_HAVE_DEFERRED_ACCEPT && defined TCP_DEFER_ACCEPT) timeout = 0; olen = sizeof(int); if (getsockopt(ls[i].fd, IPPROTO_TCP, TCP_DEFER_ACCEPT, &timeout, &olen) == -1) { err = ngx_socket_errno; if (err == NGX_EOPNOTSUPP) { continue; } ngx_log_error(NGX_LOG_NOTICE, cycle->log, err, "getsockopt(TCP_DEFER_ACCEPT) for %V failed, ignored", &ls[i].addr_text); continue; } if (olen < sizeof(int) || timeout == 0) { continue; } ls[i].deferred_accept = 1; #endif } return NGX_OK; }
四、各模块的载入
在main函数中只有 ngx_preinit_modules, 该方法只会给各module做编号处理，而 ngx_load_module 则会查找外部定义好的模块信息。
// core/ngx_module.c ngx_int_t ngx_preinit_modules(void) { ngx_uint_t i; // ngx_modules, ngx_module_names 这两个变量会在加载时初始化 for (i = 0; ngx_modules[i]; i++) { ngx_modules[i]->index = i; ngx_modules[i]->name = ngx_module_names[i]; } ngx_modules_n = i; // NGX_MAX_DYNAMIC_MODULES:128 ngx_max_module = ngx_modules_n + NGX_MAX_DYNAMIC_MODULES; return NGX_OK; } // nginx.c static char * ngx_load_module(ngx_conf_t *cf, ngx_command_t *cmd, void *conf) { #if (NGX_HAVE_DLOPEN) void *handle; char **names, **order; ngx_str_t *value, file; ngx_uint_t i; ngx_module_t *module, **modules; ngx_pool_cleanup_t *cln; if (cf->cycle->modules_used) { return "is specified too late"; } value = cf->args->elts; file = value[1]; if (ngx_conf_full_name(cf->cycle, &file, 0) != NGX_OK) { return NGX_CONF_ERROR; } cln = ngx_pool_cleanup_add(cf->cycle->pool, 0); if (cln == NULL) { return NGX_CONF_ERROR; } handle = ngx_dlopen(file.data); if (handle == NULL) { ngx_conf_log_error(NGX_LOG_EMERG, cf, 0, ngx_dlopen_n " "%s" failed (%s)", file.data, ngx_dlerror()); return NGX_CONF_ERROR; } cln->handler = ngx_unload_module; cln->data = handle; modules = ngx_dlsym(handle, "ngx_modules"); if (modules == NULL) { ngx_conf_log_error(NGX_LOG_EMERG, cf, 0, ngx_dlsym_n " "%V", "%s" failed (%s)", &value[1], "ngx_modules", ngx_dlerror()); return NGX_CONF_ERROR; } names = ngx_dlsym(handle, "ngx_module_names"); if (names == NULL) { ngx_conf_log_error(NGX_LOG_EMERG, cf, 0, ngx_dlsym_n " "%V", "%s" failed (%s)", &value[1], "ngx_module_names", ngx_dlerror()); return NGX_CONF_ERROR; } order = ngx_dlsym(handle, "ngx_module_order"); for (i = 0; modules[i]; i++) { module = modules[i]; module->name = names[i]; if (ngx_add_module(cf, &file, module, order) != NGX_OK) { return NGX_CONF_ERROR; } ngx_log_debug2(NGX_LOG_DEBUG_CORE, cf->log, 0, "module: %s i:%ui", module->name, module->index); } return NGX_CONF_OK; #else ngx_conf_log_error(NGX_LOG_EMERG, cf, 0, ""load_module" is not supported " "on this platform"); return NGX_CONF_ERROR; #endif }
五、初始化全局控制变量 ngx_cycle
ngx_cycle 是一个nginx中的重量级变量，和redis中的server变量一样。里面存储着各种配置信息，初始化socket监听，各模块的调度方式等等。
// core/ngx_cycle.c 初始化cycle信息 ngx_cycle_t * ngx_init_cycle(ngx_cycle_t *old_cycle) { void *rv; char **senv; ngx_uint_t i, n; ngx_log_t *log; ngx_time_t *tp; ngx_conf_t conf; ngx_pool_t *pool; ngx_cycle_t *cycle, **old; ngx_shm_zone_t *shm_zone, *oshm_zone; ngx_list_part_t *part, *opart; ngx_open_file_t *file; ngx_listening_t *ls, *nls; ngx_core_conf_t *ccf, *old_ccf; ngx_core_module_t *module; char hostname[NGX_MAXHOSTNAMELEN]; ngx_timezone_update(); /* force localtime update with a new timezone */ tp = ngx_timeofday(); tp->sec = 0; ngx_time_update(); log = old_cycle->log; 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; // 将old_cycle赋值到变量中，并依次将其中的各配置提取出来 cycle->old_cycle = old_cycle; 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; } 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); 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; } 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 *)); if (ngx_array_init(&cycle->config_dump, pool, 1, sizeof(ngx_conf_dump_t)) != NGX_OK) { ngx_destroy_pool(pool); return NULL; } ngx_rbtree_init(&cycle->config_dump_rbtree, &cycle->config_dump_sentinel, ngx_str_rbtree_insert_value); 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; } 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; } 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)); ngx_queue_init(&cycle->reusable_connections_queue); cycle->conf_ctx = ngx_pcalloc(pool, ngx_max_module * sizeof(void *)); if (cycle->conf_ctx == NULL) { ngx_destroy_pool(pool); return NULL; } 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] = ' '; 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); // 将 ngx_module 赋给 cycle->modules if (ngx_cycle_modules(cycle) != NGX_OK) { ngx_destroy_pool(pool); return NULL; } // 调用各模块的 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); if (rv == NULL) { ngx_destroy_pool(pool); return NULL; } cycle->conf_ctx[cycle->modules[i]->index] = rv; } } senv = environ; 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; } 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 0 log->log_level = NGX_LOG_DEBUG_ALL; #endif if (ngx_conf_param(&conf) != NGX_CONF_OK) { environ = senv; ngx_destroy_cycle_pools(&conf); return NULL; } 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); } // 调用各模块的 init_conf() 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; } } } if (ngx_process == NGX_PROCESS_SIGNALLER) { return cycle; } ccf = (ngx_core_conf_t *) ngx_get_conf(cycle->conf_ctx, ngx_core_module); 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); } } if (ngx_test_lockfile(cycle->lock_file.data, log) != NGX_OK) { goto failed; } if (ngx_create_paths(cycle, ccf->user) != NGX_OK) { goto failed; } if (ngx_log_open_default(cycle) != NGX_OK) { goto failed; } /* open the new files */ 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 } cycle->log = &cycle->new_log; pool->log = &cycle->new_log; /* create shared memory */ 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; #endif if (shm_zone[i].init(&shm_zone[i], oshm_zone[n].data) != NGX_OK) { goto failed; } goto shm_zone_found; } break; } 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; } /* handle the listening 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].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 } } // 开启socket监听，主要调用 socket(), bind(), listen() 等方法实现 if (ngx_open_listening_sockets(cycle) != NGX_OK) { goto failed; } if (!ngx_test_config) { // 配置socket 监听相关属性 ngx_configure_listening_sockets(cycle); } /* commit the new cycle configuration */ if (!ngx_use_stderr) { (void) ngx_log_redirect_stderr(cycle); } pool->log = cycle->log; // 调用各模块的 init_module() 方法，让模块初始化各自信息 if (ngx_init_modules(cycle) != NGX_OK) { /* fatal */ exit(1); } /* close and delete stuff that lefts from an old cycle */ /* free the unnecessary shared memory */ 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 */ 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 */ 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); } } ngx_destroy_pool(conf.temp_pool); if (ngx_process == NGX_PROCESS_MASTER || ngx_is_init_cycle(old_cycle)) { ngx_destroy_pool(old_cycle->pool); cycle->old_cycle = NULL; return cycle; } if (ngx_temp_pool == NULL) { ngx_temp_pool = ngx_create_pool(128, cycle->log); if (ngx_temp_pool == NULL) { ngx_log_error(NGX_LOG_EMERG, cycle->log, 0, "could not create ngx_temp_pool"); exit(1); } n = 10; if (ngx_array_init(&ngx_old_cycles, ngx_temp_pool, n, sizeof(ngx_cycle_t *)) != NGX_OK) { exit(1); } ngx_memzero(ngx_old_cycles.elts, n * sizeof(ngx_cycle_t *)); ngx_cleaner_event.handler = ngx_clean_old_cycles; ngx_cleaner_event.log = cycle->log; ngx_cleaner_event.data = &dumb; dumb.fd = (ngx_socket_t) -1; } ngx_temp_pool->log = cycle->log; old = ngx_array_push(&ngx_old_cycles); if (old == NULL) { exit(1); } *old = old_cycle; if (!ngx_cleaner_event.timer_set) { ngx_add_timer(&ngx_cleaner_event, 30000); ngx_cleaner_event.timer_set = 1; } // 正常返回初始化好的 cycle return cycle; failed: if (!ngx_is_init_cycle(old_cycle)) { old_ccf = (ngx_core_conf_t *) ngx_get_conf(old_cycle->conf_ctx, ngx_core_module); if (old_ccf->environment) { environ = old_ccf->environment; } } /* rollback the new cycle configuration */ 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].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); } } /* free the newly created shared memory */ 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.addr == NULL) { continue; } 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) { goto old_shm_zone_found; } break; } ngx_shm_free(&shm_zone[i].shm); old_shm_zone_found: continue; } if (ngx_test_config) { ngx_destroy_cycle_pools(&conf); return NULL; } ls = cycle->listening.elts; for (i = 0; i < cycle->listening.nelts; i++) { if (ls[i].fd == (ngx_socket_t) -1 || !ls[i].open) { continue; } if (ngx_close_socket(ls[i].fd) == -1) { ngx_log_error(NGX_LOG_EMERG, log, ngx_socket_errno, ngx_close_socket_n " %V failed", &ls[i].addr_text); } } ngx_destroy_cycle_pools(&conf); return NULL; }
六、处理发送给nginx的控制信号
针对 nginx -s stop|reload 等信号时，nginx是如何处理的呢？实际上，它只会运行到 ngx_signal_process(), 向原有的nginx进程发送相应的kill命令就返回了。
// ngx_cycle.c, 处理信号 ngx_int_t ngx_signal_process(ngx_cycle_t *cycle, char *sig) { ssize_t n; ngx_pid_t pid; ngx_file_t file; ngx_core_conf_t *ccf; u_char buf[NGX_INT64_LEN + 2]; ngx_log_error(NGX_LOG_NOTICE, cycle->log, 0, "signal process started"); // 根据下标获取 core_module 配置信息 ccf = (ngx_core_conf_t *) ngx_get_conf(cycle->conf_ctx, ngx_core_module); ngx_memzero(&file, sizeof(ngx_file_t)); file.name = ccf->pid; file.log = cycle->log; file.fd = ngx_open_file(file.name.data, NGX_FILE_RDONLY, NGX_FILE_OPEN, NGX_FILE_DEFAULT_ACCESS); if (file.fd == NGX_INVALID_FILE) { ngx_log_error(NGX_LOG_ERR, cycle->log, ngx_errno, ngx_open_file_n " "%s" failed", file.name.data); return 1; } n = ngx_read_file(&file, buf, NGX_INT64_LEN + 2, 0); if (ngx_close_file(file.fd) == NGX_FILE_ERROR) { ngx_log_error(NGX_LOG_ALERT, cycle->log, ngx_errno, ngx_close_file_n " "%s" failed", file.name.data); } if (n == NGX_ERROR) { return 1; } while (n-- && (buf[n] == CR || buf[n] == LF)) { /* void */ } pid = ngx_atoi(buf, ++n); if (pid == (ngx_pid_t) NGX_ERROR) { ngx_log_error(NGX_LOG_ERR, cycle->log, 0, "invalid PID number "%*s" in "%s"", n, buf, file.name.data); return 1; } // 根据 sig 处理pid 进程状态 return ngx_os_signal_process(cycle, sig, pid); } ngx_int_t ngx_os_signal_process(ngx_cycle_t *cycle, char *name, ngx_pid_t pid) { ngx_signal_t *sig; // 遍历所有的 signals, 找到匹配的方法后响应 for (sig = signals; sig->signo != 0; sig++) { if (ngx_strcmp(name, sig->name) == 0) { // 操作系统只进行 kill 调用即可 // 而该命令会被正运行的master进程接收到，做后续处理。 if (kill(pid, sig->signo) != -1) { return 0; } ngx_log_error(NGX_LOG_ALERT, cycle->log, ngx_errno, "kill(%P, %d) failed", pid, sig->signo); } } return 1; } // nginx 定义的各种signal typedef struct { int signo; char *signame; char *name; void (*handler)(int signo, siginfo_t *siginfo, void *ucontext); } ngx_signal_t; // os/unix/ngx_process.c ngx_signal_t signals[] = { { ngx_signal_value(NGX_RECONFIGURE_SIGNAL), /* signo SIGHUP */ "SIG" ngx_value(NGX_RECONFIGURE_SIGNAL), /* *signame */ "reload", /* *name */ ngx_signal_handler }, /* *handler */ { ngx_signal_value(NGX_REOPEN_SIGNAL), /* signo SIGINFO */ "SIG" ngx_value(NGX_REOPEN_SIGNAL), "reopen", ngx_signal_handler }, { ngx_signal_value(NGX_NOACCEPT_SIGNAL), "SIG" ngx_value(NGX_NOACCEPT_SIGNAL), "", ngx_signal_handler }, { ngx_signal_value(NGX_TERMINATE_SIGNAL), /* signo SIGTERM */ "SIG" ngx_value(NGX_TERMINATE_SIGNAL), "stop", ngx_signal_handler }, { ngx_signal_value(NGX_SHUTDOWN_SIGNAL), /* signo SIGQUIT */ "SIG" ngx_value(NGX_SHUTDOWN_SIGNAL), "quit", ngx_signal_handler }, { ngx_signal_value(NGX_CHANGEBIN_SIGNAL), "SIG" ngx_value(NGX_CHANGEBIN_SIGNAL), "", ngx_signal_handler }, { SIGALRM, "SIGALRM", "", ngx_signal_handler }, { SIGINT, "SIGINT", "", ngx_signal_handler }, { SIGIO, "SIGIO", "", ngx_signal_handler }, { SIGCHLD, "SIGCHLD", "", ngx_signal_handler }, { SIGSYS, "SIGSYS, SIG_IGN", "", NULL }, { SIGPIPE, "SIGPIPE, SIG_IGN", "", NULL }, { 0, NULL, "", NULL } };
七、master循环服务与worker进程循环服务
main方法运行到最后，一定是以死循环的形式呈现服务的。而 ngx_master_process_cycle 则是处理这两个事情的函数。其主要作用就是，根据配置参数启动worker进程并进入循环服务，自身以master进程地形式运行循环服务。
// os/unix/ngx_process_cycle.c, 主循环服务 void ngx_master_process_cycle(ngx_cycle_t *cycle) { char *title; u_char *p; size_t size; ngx_int_t i; ngx_uint_t n, sigio; sigset_t set; struct itimerval itv; ngx_uint_t live; ngx_msec_t delay; ngx_listening_t *ls; ngx_core_conf_t *ccf; sigemptyset(&set); sigaddset(&set, SIGCHLD); sigaddset(&set, SIGALRM); sigaddset(&set, SIGIO); sigaddset(&set, SIGINT); sigaddset(&set, ngx_signal_value(NGX_RECONFIGURE_SIGNAL)); sigaddset(&set, ngx_signal_value(NGX_REOPEN_SIGNAL)); sigaddset(&set, ngx_signal_value(NGX_NOACCEPT_SIGNAL)); sigaddset(&set, ngx_signal_value(NGX_TERMINATE_SIGNAL)); sigaddset(&set, ngx_signal_value(NGX_SHUTDOWN_SIGNAL)); sigaddset(&set, ngx_signal_value(NGX_CHANGEBIN_SIGNAL)); if (sigprocmask(SIG_BLOCK, &set, NULL) == -1) { ngx_log_error(NGX_LOG_ALERT, cycle->log, ngx_errno, "sigprocmask() failed"); } sigemptyset(&set); // master process size = sizeof(master_process); for (i = 0; i < ngx_argc; i++) { size += ngx_strlen(ngx_argv[i]) + 1; } title = ngx_pnalloc(cycle->pool, size); if (title == NULL) { /* fatal */ exit(2); } p = ngx_cpymem(title, master_process, sizeof(master_process) - 1); for (i = 0; i < ngx_argc; i++) { *p++ = ' '; p = ngx_cpystrn(p, (u_char *) ngx_argv[i], size); } ngx_setproctitle(title); ccf = (ngx_core_conf_t *) ngx_get_conf(cycle->conf_ctx, ngx_core_module); // 开启请求处理子进程 "worker process" ngx_start_worker_processes(cycle, ccf->worker_processes, NGX_PROCESS_RESPAWN); // 开启管理进程 "cache manager" / "cache loader" ngx_start_cache_manager_processes(cycle, 0); ngx_new_binary = 0; delay = 0; sigio = 0; live = 1; // master 进程主循环服务 // 监听外部各种控制信号 for ( ;; ) { if (delay) { if (ngx_sigalrm) { sigio = 0; delay *= 2; ngx_sigalrm = 0; } ngx_log_debug1(NGX_LOG_DEBUG_EVENT, cycle->log, 0, "termination cycle: %M", delay); itv.it_interval.tv_sec = 0; itv.it_interval.tv_usec = 0; itv.it_value.tv_sec = delay / 1000; itv.it_value.tv_usec = (delay % 1000 ) * 1000; if (setitimer(ITIMER_REAL, &itv, NULL) == -1) { ngx_log_error(NGX_LOG_ALERT, cycle->log, ngx_errno, "setitimer() failed"); } } ngx_log_debug0(NGX_LOG_DEBUG_EVENT, cycle->log, 0, "sigsuspend"); sigsuspend(&set); ngx_time_update(); ngx_log_debug1(NGX_LOG_DEBUG_EVENT, cycle->log, 0, "wake up, sigio %i", sigio); if (ngx_reap) { ngx_reap = 0; ngx_log_debug0(NGX_LOG_DEBUG_EVENT, cycle->log, 0, "reap children"); live = ngx_reap_children(cycle); } // master 进程退出，删除pid文件，关闭socket监听等等 if (!live && (ngx_terminate || ngx_quit)) { ngx_master_process_exit(cycle); } if (ngx_terminate) { if (delay == 0) { delay = 50; } if (sigio) { sigio--; continue; } sigio = ccf->worker_processes + 2 /* cache processes */; // 通知子进程进行关闭处理 if (delay > 1000) { ngx_signal_worker_processes(cycle, SIGKILL); } else { ngx_signal_worker_processes(cycle, ngx_signal_value(NGX_TERMINATE_SIGNAL)); } continue; } if (ngx_quit) { ngx_signal_worker_processes(cycle, ngx_signal_value(NGX_SHUTDOWN_SIGNAL)); ls = cycle->listening.elts; for (n = 0; n < cycle->listening.nelts; n++) { if (ngx_close_socket(ls[n].fd) == -1) { ngx_log_error(NGX_LOG_EMERG, cycle->log, ngx_socket_errno, ngx_close_socket_n " %V failed", &ls[n].addr_text); } } cycle->listening.nelts = 0; continue; } // 重启nginx服务 if (ngx_reconfigure) { ngx_reconfigure = 0; // new_binary if (ngx_new_binary) { ngx_start_worker_processes(cycle, ccf->worker_processes, NGX_PROCESS_RESPAWN); ngx_start_cache_manager_processes(cycle, 0); ngx_noaccepting = 0; continue; } ngx_log_error(NGX_LOG_NOTICE, cycle->log, 0, "reconfiguring"); // 重新初始化 cycle 信息 cycle = ngx_init_cycle(cycle); if (cycle == NULL) { cycle = (ngx_cycle_t *) ngx_cycle; continue; } // 重启子进程 ngx_cycle = cycle; ccf = (ngx_core_conf_t *) ngx_get_conf(cycle->conf_ctx, ngx_core_module); ngx_start_worker_processes(cycle, ccf->worker_processes, NGX_PROCESS_JUST_RESPAWN); ngx_start_cache_manager_processes(cycle, 1); /* allow new processes to start */ ngx_msleep(100); live = 1; ngx_signal_worker_processes(cycle, ngx_signal_value(NGX_SHUTDOWN_SIGNAL)); } if (ngx_restart) { ngx_restart = 0; ngx_start_worker_processes(cycle, ccf->worker_processes, NGX_PROCESS_RESPAWN); ngx_start_cache_manager_processes(cycle, 0); live = 1; } if (ngx_reopen) { ngx_reopen = 0; ngx_log_error(NGX_LOG_NOTICE, cycle->log, 0, "reopening logs"); ngx_reopen_files(cycle, ccf->user); ngx_signal_worker_processes(cycle, ngx_signal_value(NGX_REOPEN_SIGNAL)); } if (ngx_change_binary) { ngx_change_binary = 0; ngx_log_error(NGX_LOG_NOTICE, cycle->log, 0, "changing binary"); ngx_new_binary = ngx_exec_new_binary(cycle, ngx_argv); } if (ngx_noaccept) { ngx_noaccept = 0; ngx_noaccepting = 1; ngx_signal_worker_processes(cycle, ngx_signal_value(NGX_SHUTDOWN_SIGNAL)); } } } // ngx_process_cycle.c, 依据配置信息，开启子进程循环服务 static void ngx_start_worker_processes(ngx_cycle_t *cycle, ngx_int_t n, ngx_int_t type) { ngx_int_t i; ngx_channel_t ch; ngx_log_error(NGX_LOG_NOTICE, cycle->log, 0, "start worker processes"); ngx_memzero(&ch, sizeof(ngx_channel_t)); ch.command = NGX_CMD_OPEN_CHANNEL; for (i = 0; i < n; i++) { // 创建子进程，然后运行 ngx_worker_process_cycle 逻辑 ngx_spawn_process(cycle, ngx_worker_process_cycle, (void *) (intptr_t) i, "worker process", type); ch.pid = ngx_processes[ngx_process_slot].pid; ch.slot = ngx_process_slot; ch.fd = ngx_processes[ngx_process_slot].channel[0]; ngx_pass_open_channel(cycle, &ch); } } // ngx_process.c, 创建子进程 ngx_pid_t ngx_spawn_process(ngx_cycle_t *cycle, ngx_spawn_proc_pt proc, void *data, char *name, ngx_int_t respawn) { u_long on; ngx_pid_t pid; ngx_int_t s; if (respawn >= 0) { s = respawn; } else { for (s = 0; s < ngx_last_process; s++) { if (ngx_processes[s].pid == -1) { break; } } if (s == NGX_MAX_PROCESSES) { ngx_log_error(NGX_LOG_ALERT, cycle->log, 0, "no more than %d processes can be spawned", NGX_MAX_PROCESSES); return NGX_INVALID_PID; } } if (respawn != NGX_PROCESS_DETACHED) { /* Solaris 9 still has no AF_LOCAL */ if (socketpair(AF_UNIX, SOCK_STREAM, 0, ngx_processes[s].channel) == -1) { ngx_log_error(NGX_LOG_ALERT, cycle->log, ngx_errno, "socketpair() failed while spawning "%s"", name); return NGX_INVALID_PID; } ngx_log_debug2(NGX_LOG_DEBUG_CORE, cycle->log, 0, "channel %d:%d", ngx_processes[s].channel[0], ngx_processes[s].channel[1]); if (ngx_nonblocking(ngx_processes[s].channel[0]) == -1) { ngx_log_error(NGX_LOG_ALERT, cycle->log, ngx_errno, ngx_nonblocking_n " failed while spawning "%s"", name); ngx_close_channel(ngx_processes[s].channel, cycle->log); return NGX_INVALID_PID; } if (ngx_nonblocking(ngx_processes[s].channel[1]) == -1) { ngx_log_error(NGX_LOG_ALERT, cycle->log, ngx_errno, ngx_nonblocking_n " failed while spawning "%s"", name); ngx_close_channel(ngx_processes[s].channel, cycle->log); return NGX_INVALID_PID; } on = 1; if (ioctl(ngx_processes[s].channel[0], FIOASYNC, &on) == -1) { ngx_log_error(NGX_LOG_ALERT, cycle->log, ngx_errno, "ioctl(FIOASYNC) failed while spawning "%s"", name); ngx_close_channel(ngx_processes[s].channel, cycle->log); return NGX_INVALID_PID; } if (fcntl(ngx_processes[s].channel[0], F_SETOWN, ngx_pid) == -1) { ngx_log_error(NGX_LOG_ALERT, cycle->log, ngx_errno, "fcntl(F_SETOWN) failed while spawning "%s"", name); ngx_close_channel(ngx_processes[s].channel, cycle->log); return NGX_INVALID_PID; } if (fcntl(ngx_processes[s].channel[0], F_SETFD, FD_CLOEXEC) == -1) { ngx_log_error(NGX_LOG_ALERT, cycle->log, ngx_errno, "fcntl(FD_CLOEXEC) failed while spawning "%s"", name); ngx_close_channel(ngx_processes[s].channel, cycle->log); return NGX_INVALID_PID; } if (fcntl(ngx_processes[s].channel[1], F_SETFD, FD_CLOEXEC) == -1) { ngx_log_error(NGX_LOG_ALERT, cycle->log, ngx_errno, "fcntl(FD_CLOEXEC) failed while spawning "%s"", name); ngx_close_channel(ngx_processes[s].channel, cycle->log); return NGX_INVALID_PID; } ngx_channel = ngx_processes[s].channel[1]; } else { ngx_processes[s].channel[0] = -1; ngx_processes[s].channel[1] = -1; } ngx_process_slot = s; // 创建子进程 pid = fork(); switch (pid) { case -1: ngx_log_error(NGX_LOG_ALERT, cycle->log, ngx_errno, "fork() failed while spawning "%s"", name); ngx_close_channel(ngx_processes[s].channel, cycle->log); return NGX_INVALID_PID; case 0: ngx_parent = ngx_pid; ngx_pid = ngx_getpid(); // 子进程中直接调用 ngx_worker_process_cycle() 方法进行事务处理 proc(cycle, data); break; default: // 父进程则直接返回了 break; } ngx_log_error(NGX_LOG_NOTICE, cycle->log, 0, "start %s %P", name, pid); ngx_processes[s].pid = pid; ngx_processes[s].exited = 0; if (respawn >= 0) { return pid; } ngx_processes[s].proc = proc; ngx_processes[s].data = data; ngx_processes[s].name = name; ngx_processes[s].exiting = 0; switch (respawn) { case NGX_PROCESS_NORESPAWN: ngx_processes[s].respawn = 0; ngx_processes[s].just_spawn = 0; ngx_processes[s].detached = 0; break; case NGX_PROCESS_JUST_SPAWN: ngx_processes[s].respawn = 0; ngx_processes[s].just_spawn = 1; ngx_processes[s].detached = 0; break; case NGX_PROCESS_RESPAWN: ngx_processes[s].respawn = 1; ngx_processes[s].just_spawn = 0; ngx_processes[s].detached = 0; break; case NGX_PROCESS_JUST_RESPAWN: ngx_processes[s].respawn = 1; ngx_processes[s].just_spawn = 1; ngx_processes[s].detached = 0; break; case NGX_PROCESS_DETACHED: ngx_processes[s].respawn = 0; ngx_processes[s].just_spawn = 0; ngx_processes[s].detached = 1; break; } if (s == ngx_last_process) { ngx_last_process++; } return pid; } // ngx_process_cycle.c, 子进程处理服务 static void ngx_worker_process_cycle(ngx_cycle_t *cycle, void *data) { ngx_int_t worker = (intptr_t) data; ngx_process = NGX_PROCESS_WORKER; ngx_worker = worker; ngx_worker_process_init(cycle, worker); ngx_setproctitle("worker process"); // 子进程中的死循环服务，通过 ngx_process_events_and_timers 进行事件处理 for ( ;; ) { // 当需要子进程退出时，会调用 ngx_worker_process_exit(), 并最终调用 exit(0); 直接退出而无需执行后续代码 if (ngx_exiting) { if (ngx_event_no_timers_left() == NGX_OK) { ngx_log_error(NGX_LOG_NOTICE, cycle->log, 0, "exiting"); ngx_worker_process_exit(cycle); } } ngx_log_debug0(NGX_LOG_DEBUG_EVENT, cycle->log, 0, "worker cycle"); // 主要逻辑处理如：网络事件 accept, read, 锁获取等等 ngx_process_events_and_timers(cycle); if (ngx_terminate) { ngx_log_error(NGX_LOG_NOTICE, cycle->log, 0, "exiting"); ngx_worker_process_exit(cycle); } if (ngx_quit) { ngx_quit = 0; ngx_log_error(NGX_LOG_NOTICE, cycle->log, 0, "gracefully shutting down"); ngx_setproctitle("worker process is shutting down"); if (!ngx_exiting) { ngx_exiting = 1; ngx_set_shutdown_timer(cycle); ngx_close_listening_sockets(cycle); ngx_close_idle_connections(cycle); } } if (ngx_reopen) { ngx_reopen = 0; ngx_log_error(NGX_LOG_NOTICE, cycle->log, 0, "reopening logs"); ngx_reopen_files(cycle, -1); } } }
到此，nginx整个启动流程就分析完了，有了个整体概念。再要研究，我们就得要针对具体的功能点来分析了。请听下回分解。