查看源代碼入門
這是一篇關於NGINX的MAIN()函數入門說明文章，相比其他這篇十分枯燥，其實寫的時候更是無聊，不過學了這么長時間的WEB開發，連NGINX源代碼都沒有讀下來，總是覺得有些缺憾，希望這一次可以彌補一下。
一、下載NGINX
- 下載地址：http://nginx.org/en/download.html
- tar -zxvf *.tar.gz && ./configure && make && sudo make install
- 查看NGINX目錄有如下文件夾：
-
auto CHANGES CHANGES.ru conf configure contrib html LICENSE Makefile man objs README src
-
二、使用gdb跟蹤查找入口文件
很多朋友看見NGINX目錄有很多的內容，就會頭疼，不知道從哪里開始，下面就分享一個方法。進入objs目錄，會發現nginx是可執行文件，使用gdb跟蹤一下（如果沒有gdb，執行命令：sudo yum install yum安裝即可），依次執行如下命令：
2.1 gdb nginx
進入nginx程序
GNU gdb (GDB) Red Hat Enterprise Linux (7.2-60.el6_4.1) Copyright (C) 2010 Free Software Foundation, Inc. License GPLv3+: GNU GPL version 3 or later <http://gnu.org/licenses/gpl.html> This is free software: you are free to change and redistribute it. There is NO WARRANTY, to the extent permitted by law. Type "show copying" and "show warranty" for details. This GDB was configured as "x86_64-redhat-linux-gnu". For bug reporting instructions, please see: <http://www.gnu.org/software/gdb/bugs/>... Reading symbols from /root/soft/ngx_openresty-1.4.1.1/build/nginx-1.4.1/objs/nginx...done.
2.2 l main
目的是查看main函數
(gdb) l main 198 static char **ngx_os_environ; 199 200 201 int ngx_cdecl 202 main(int argc, char *const *argv) 203 { 204 ngx_int_t i; 205 ngx_log_t *log; 206 ngx_cycle_t *cycle, init_cycle; 207 ngx_core_conf_t *ccf;
2.3 i li main
查看main()函數的位置
(gdb) i li main Line 203 of "src/core/nginx.c" starts at address 0x4168cb <main> and ends at 0x4168e1 <main+22>.
如上就知道了入口程序文件是：src/core/nginx.c
三、main()函數
int ngx_cdecl main(int argc, char *const *argv) { ngx_int_t i; ngx_log_t *log; ngx_cycle_t *cycle, init_cycle; ngx_core_conf_t *ccf; //上面是四個堆棧的常量，沒啥別的意思。nginx的結構都是_t結束的。 ngx_debug_init();//nginx的函數都是ngx_開頭的。下面有解釋 if (ngx_strerror_init() != NGX_OK) { return 1;//如果啟動失敗 } if (ngx_get_options(argc, argv) != NGX_OK) { return 1;//檢測命令行參數異常 } if (ngx_show_version) {//ngx_show_version是一個全局變量，可以在gdb里面查看（p ngx_show_version或者i var ngx_show_version） ngx_write_stderr("nginx version: " NGINX_VER NGX_LINEFEED); if (ngx_show_help) {//自我幫助信息，執行:"nginx -?"時候輸出的信息 ngx_write_stderr( "Usage: nginx [-?hvVtq] [-s signal] [-c filename] " "[-p prefix] [-g directives]" NGX_LINEFEED NGX_LINEFEED "Options:" NGX_LINEFEED " -?,-h : this help" NGX_LINEFEED " -v : show version and exit" NGX_LINEFEED " -V : show version and configure options then exit" NGX_LINEFEED " -t : test configuration and exit" NGX_LINEFEED " -q : suppress non-error messages " "during configuration testing" NGX_LINEFEED " -s signal : send signal to a master process: " "stop, quit, reopen, reload" NGX_LINEFEED #ifdef NGX_PREFIX " -p prefix : set prefix path (default: " NGX_PREFIX ")" NGX_LINEFEED #else " -p prefix : set prefix path (default: NONE)" NGX_LINEFEED #endif " -c filename : set configuration file (default: " NGX_CONF_PATH ")" NGX_LINEFEED " -g directives : set global directives out of configuration " "file" NGX_LINEFEED NGX_LINEFEED ); } if (ngx_show_configure) { ngx_write_stderr( #ifdef NGX_COMPILER "built by " NGX_COMPILER NGX_LINEFEED #endif #if (NGX_SSL) #ifdef SSL_CTRL_SET_TLSEXT_HOSTNAME "TLS SNI support enabled" NGX_LINEFEED #else "TLS SNI support disabled" NGX_LINEFEED #endif #endif "configure arguments:" NGX_CONFIGURE NGX_LINEFEED); } if (!ngx_test_config) { return 0; } } /* TODO */ ngx_max_sockets = -1; ngx_time_init();//時間初始化 #if (NGX_PCRE) ngx_regex_init();//宏開關 #endif ngx_pid = ngx_getpid(); log = ngx_log_init(ngx_prefix);//日志初始化 if (log == NULL) { return 1; } /* STUB */ #if (NGX_OPENSSL) ngx_ssl_init(log);//ssh初始化 #endif /* * init_cycle->log is required for signal handlers and * ngx_process_options() */ ngx_memzero(&init_cycle, sizeof(ngx_cycle_t));//init_cycle清零 init_cycle.log = log; ngx_cycle = &init_cycle; init_cycle.pool = ngx_create_pool(1024, log);//建立內存池 if (init_cycle.pool == NULL) { return 1; } if (ngx_save_argv(&init_cycle, argc, argv) != NGX_OK) { return 1; } if (ngx_process_options(&init_cycle) != NGX_OK) { return 1; } if (ngx_os_init(log) != NGX_OK) { return 1; } /* * ngx_crc32_table_init() requires ngx_cacheline_size set in ngx_os_init() */ if (ngx_crc32_table_init() != NGX_OK) { return 1;//crc算法 } if (ngx_add_inherited_sockets(&init_cycle) != NGX_OK) { return 1; } ngx_max_module = 0; for (i = 0; ngx_modules[i]; i++) { //查看一共多少模塊 ngx_modules[i]->index = ngx_max_module++; } cycle = ngx_init_cycle(&init_cycle);//初始化生命周期，下面有講 if (cycle == NULL) { if (ngx_test_config) { ngx_log_stderr(0, "configuration file %s test failed", init_cycle.conf_file.data); } return 1; } if (ngx_test_config) { if (!ngx_quiet_mode) { ngx_log_stderr(0, "configuration file %s test is successful", cycle->conf_file.data); } return 0; } if (ngx_signal) { return ngx_signal_process(cycle, ngx_signal); } 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) if (ngx_init_signals(cycle->log) != NGX_OK) { return 1; } if (!ngx_inherited && ccf->daemon) { if (ngx_daemon(cycle->log) != NGX_OK) { return 1; } ngx_daemonized = 1; } if (ngx_inherited) { ngx_daemonized = 1; } #endif if (ngx_create_pidfile(&ccf->pid, cycle->log) != NGX_OK) { return 1; } if (cycle->log->file->fd != ngx_stderr) { if (ngx_set_stderr(cycle->log->file->fd) == NGX_FILE_ERROR) { ngx_log_error(NGX_LOG_EMERG, cycle->log, ngx_errno, ngx_set_stderr_n " failed"); 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; }
無疑，里面的中文內容肯定是我寫的注釋。
3.1 ngx_debug_init
使用gdb執行:"i li ngx_debug_init"
(gdb) i li ngx_debug_init Function "ngx_debug_init" not defined. (gdb)
沒有找到，這個時候只能在文件里面搜索
@~/soft/ngx_openresty-1.4.1.1/build/nginx-1.4.1/src $ grep -r ngx_debug_init * core/nginx.c: ngx_debug_init(); os/unix/ngx_freebsd_init.c:ngx_debug_init() os/unix/ngx_solaris_config.h:#define ngx_debug_init() os/unix/ngx_linux_config.h:#define ngx_debug_init() os/unix/ngx_darwin_init.c:ngx_debug_init() os/unix/ngx_freebsd.h:void ngx_debug_init(void); os/unix/ngx_posix_config.h:#define ngx_debug_init() os/unix/ngx_darwin.h:void ngx_debug_init(void);
可見這是一個操作系統相關的內容，先初始化一下。但是什么都沒做，所以gdb搜索不到。
3.2 ngx_strerror_init
(gdb) i li ngx_strerror_init Line 47 of "src/os/unix/ngx_errno.c" starts at address 0x42d8c9 <ngx_strerror_init> and ends at 0x42d8d7 <ngx_strerror_init+14>.
然后打開文件ngx_errno.c文件：
ngx_int_t ngx_strerror_init(void) { char *msg; u_char *p; size_t len; ngx_err_t err; //定義四個堆棧變量 /* * ngx_strerror() is not ready to work at this stage, therefore, * malloc() is used and possible errors are logged using strerror(). */ len = NGX_SYS_NERR * sizeof(ngx_str_t); //計算長度,注意NGX_SYS_NERR不是在src里面的，而是編譯的時候根據操作系統的不同而生成的不內容，這里是在objs/ngx_auto_config.h里面，定義為:135。 ngx_sys_errlist = malloc(len);//申請空間 if (ngx_sys_errlist == NULL) { goto failed; } for (err = 0; err < NGX_SYS_NERR; err++) { msg = strerror(err);//如果不是以ngx_開頭的，都是系統函數或者其他的庫函數。這里是建立一個字符串描述這個錯誤號 len = ngx_strlen(msg); p = malloc(len); if (p == NULL) { goto failed; } ngx_memcpy(p, msg, len);//系統的錯誤信息拷貝到自己的空間。 ngx_sys_errlist[err].len = len; ngx_sys_errlist[err].data = p; } return NGX_OK; failed: err = errno; ngx_log_stderr(0, "malloc(%uz) failed (%d: %s)", len, err, strerror(err)); return NGX_ERROR; }
作用是將全局的錯誤信息復制到一個數組里面，暫時不知道是為什么
3.3 ngx_init_cycle
初始化生命周期。core/ngx_cycle.c，這個函數相當的長。
ngx_cycle_t * ngx_init_cycle(ngx_cycle_t *old_cycle) { void *rv; char **senv, **env; 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; cycle->new_log.log_level = NGX_LOG_ERR; 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; 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 (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; 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; 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] = '\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); for (i = 0; ngx_modules[i]; i++) { if (ngx_modules[i]->type != NGX_CORE_MODULE) { continue; } module = ngx_modules[i]->ctx; if (module->create_conf) { rv = module->create_conf(cycle); if (rv == NULL) { ngx_destroy_pool(pool); return NULL; } cycle->conf_ctx[ngx_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) {//解析配置文件，各個模塊讀取自己的參數 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; } //cycle->conf，指向一塊內存，多級指針數組，共44個模塊。第0個是核心模塊的數據結構，ngx_core_module，如后面3.5所示；第3個是一個指向指針的指針，ngx_events_module。
//第六個指向的ngx的http模塊，ngx_http_core數據結構，如3.6所示 if (ngx_test_config && !ngx_quiet_mode) { ngx_log_stderr(0, "the configuration file %s syntax is ok", cycle->conf_file.data); } for (i = 0; ngx_modules[i]; i++) { if (ngx_modules[i]->type != NGX_CORE_MODULE) { continue; } module = ngx_modules[i]->ctx; if (module->init_conf) { if (module->init_conf(cycle, cycle->conf_ctx[ngx_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 (cycle->new_log.file == NULL) { cycle->new_log.file = ngx_conf_open_file(cycle, &error_log); if (cycle->new_log.file == NULL) { 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].shm.addr = oshm_zone[n].shm.addr; if (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; } 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 (ngx_cmp_sockaddr(nls[n].sockaddr, ls[i].sockaddr) == NGX_OK) { nls[n].fd = ls[i].fd; nls[n].previous = &ls[i]; ls[i].remain = 1; if (ls[n].backlog != nls[i].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[n].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 break; } } if (nls[n].fd == -1) { nls[n].open = 1; } } } 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 && cycle->log->file->fd != ngx_stderr) { if (ngx_set_stderr(cycle->log->file->fd) == NGX_FILE_ERROR) { ngx_log_error(NGX_LOG_ALERT, cycle->log, ngx_errno, ngx_set_stderr_n " failed"); } } pool->log = cycle->log; for (i = 0; ngx_modules[i]; i++) { if (ngx_modules[i]->init_module) { if (ngx_modules[i]->init_module(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 && 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); 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 == -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)) { /* * perl_destruct() frees environ, if it is not the same as it was at * perl_construct() time, therefore we save the previous cycle * environment before ngx_conf_parse() where it will be changed. */ env = environ; environ = senv; ngx_destroy_pool(old_cycle->pool); cycle->old_cycle = NULL; environ = env; 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; ngx_old_cycles.elts = ngx_pcalloc(ngx_temp_pool, n * sizeof(ngx_cycle_t *)); if (ngx_old_cycles.elts == NULL) { exit(1); } ngx_old_cycles.nelts = 0; ngx_old_cycles.size = sizeof(ngx_cycle_t *); ngx_old_cycles.nalloc = n; ngx_old_cycles.pool = ngx_temp_pool; 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; } 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); } } 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 == -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; }
修改配置參數之后，可以不重新啟動服務，而可以生效。他把所有nginx的參數都放入到一個參數里面，如果修改，那么他會慢慢的修改過來。
3.4 ngx_cycle_s
文件：src/core/ngx_cycle.h
struct ngx_cycle_s { void ****conf_ctx;//解析配置文件， ngx_pool_t *pool; ngx_log_t *log; ngx_log_t new_log; ngx_connection_t **files; ngx_connection_t *free_connections; ngx_uint_t free_connection_n; ngx_queue_t reusable_connections_queue; ngx_array_t listening; ngx_array_t paths; ngx_list_t open_files; ngx_list_t shared_memory; ngx_uint_t connection_n; ngx_uint_t files_n; ngx_connection_t *connections; ngx_event_t *read_events; ngx_event_t *write_events; ngx_cycle_t *old_cycle; ngx_str_t conf_file; ngx_str_t conf_param; ngx_str_t conf_prefix; ngx_str_t prefix; ngx_str_t lock_file; ngx_str_t hostname; };
3.5 ngx_core_conf_t 結構體
typedef struct { ngx_flag_t daemon; ngx_flag_t master; ngx_msec_t timer_resolution; ngx_int_t worker_processes; //進程數量 ngx_int_t debug_points; ngx_int_t rlimit_nofile; ngx_int_t rlimit_sigpending; off_t rlimit_core; int priority; ngx_uint_t cpu_affinity_n; uint64_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_t env; char **environment; #if (NGX_THREADS) ngx_int_t worker_threads; size_t thread_stack_size; #endif } ngx_core_conf_t;
3.6 ngx_http_conf_cxt_t結構體
在src/http/ngx_http_config.h里面
17 typedef struct { 18 void **main_conf; //http的子模塊 19 void **srv_conf; //所有server的參數 20 void **loc_conf; //所有url的參數 21 } ngx_http_conf_ctx_t;