ngx_cycle 的核心初始化工作(初步)

2014-12-30 18:06:35   最后更新: 2014-12-30 18:06:35   访问数量:1011




下面就到了最核心的初始化过程了

// 全部初始化工作,包括时间、内存池、配置文件、共享内存 // 、监听连接数组、所有模块的初始化, // 以及配置及log文件创建、连接开启监听 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; }

 

如注释中已经写的,这个函数进行了 nginx 最核心部分的初始化工作

前面的日志中,我们说过,nginx 的整个初始化过程都是围绕全局变量 ngx_cycle 展开的,重点就在这个函数中

说到 ngx_cycle 变量就不得不说 ngx_cycle_t 类型,它记录了 nginx 所需的各种核心的信息

// struct ngx_cycle_s // nginx 运行核心结构 {{{ struct ngx_cycle_s { void ****conf_ctx; // 配置上下文数组(含所有模块) ngx_pool_t *pool; // 内存池起始地址 ngx_log_t *log; // 日志 ngx_log_t new_log; /* unsigned log_use_stderr:1; */ ngx_uint_t log_use_stderr; ngx_connection_t **files; // 连接文件 ngx_connection_t *free_connections; // 空闲连接 ngx_uint_t free_connection_n; // 空闲连接数 ngx_queue_t reusable_connections_queue; // 再利用连接队列 ngx_array_t listening; // 监听数组 ngx_array_t paths; // 路径数组 ngx_list_t open_files; // 已打开文件链表 ngx_list_t shared_memory; // 共享内存链表 ngx_uint_t connection_n; // 连接个数 ngx_uint_t files_n; // 打开文件数 ngx_connection_t *connections; // 连接 ngx_event_t *read_events; // 读事件 ngx_event_t *write_events; // 写事件 ngx_cycle_t *old_cycle; ngx_str_t conf_file; // 配置文件 ngx_str_t conf_param; // 配置参数 ngx_str_t conf_prefix; // 配置前缀 ngx_str_t prefix; // 程序目录路径 ngx_str_t lock_file; // 锁文件 ngx_str_t hostname; // 主机名 }; // }}}

 

 

下面我们就要进入这个 829 行的巨型函数里一探究竟了

// ngx_cycle_t * ngx_init_cycle(ngx_cycle_t *old_cycle) // 环境初始化 {{{ 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 */ // ngx_timeofday() 是一个宏,创建了一个 ngx_time_t 指针类型变量 tp = ngx_timeofday(); tp->sec = 0; // 更新 ngx_cached_http_time、ngx_cached_err_log_time // ngx_cached_http_log_time、ngx_cached_http_log_iso8601 // ngx_cached_syslog_time ngx_time_update(); log = old_cycle->log; // 创建内存池 16 KB, 16 位对齐 pool = ngx_create_pool(NGX_CYCLE_POOL_SIZE, log); if (pool == NULL) { return NULL; } pool->log = log; // 在内存池中分配空间存储新的 cycle 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; // 拷贝配置信息 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; } // 共享文件、内存链表初始化 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; } // 监听链接数组初始化 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; // nginx 复用连接队列初始化(双链接指针循环队列) 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; } // 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); 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) { // 创建模块配置 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 ? */ // 保存配置文件中所有指令 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 // 获取配置文件中的全部参数 if (ngx_conf_param(&conf) != NGX_CONF_OK) { environ = senv; ngx_destroy_cycle_pools(&conf); return NULL; } // 解析配置文件 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); } // 初始化所有模块 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; } // 获取内核模块配置文件信息 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); } } // 测试文件打开和读写 if (ngx_test_lockfile(cycle->lock_file.data, log) != NGX_OK) { goto failed; } // 创建全部配置文件 if (ngx_create_paths(cycle, ccf->user) != NGX_OK) { goto failed; } // 测试 log 是否可以打开 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; } // 链表每个元素都是一个数组,数组满后会创建新的链表元素 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) // 改变已打开文件的性质:如果执行 exec,系统将自动关闭该文件 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; // 初始化共享内存 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; } // 将共享文件映射到共享内存 if (ngx_shm_alloc(&shm_zone[i].shm) != NGX_OK) { goto failed; } // 初始化共享内存结构 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, 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 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; 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 == (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)) { /* * 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 == (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; } // }}}

 

代码依然是很清晰的

// 设置系统时区 ngx_timezone_update(); /* force localtime update with a new timezone */ // ngx_timeofday() 是一个宏,创建了一个 ngx_time_t 指针类型变量 tp = ngx_timeofday(); tp->sec = 0; // 更新 ngx_cached_http_time、ngx_cached_err_log_time // ngx_cached_http_log_time、ngx_cached_http_log_iso8601 // ngx_cached_syslog_time ngx_time_update();

 

这里设置了系统的时区环境变量,并且更新了几个时间相关的全局变量

用全局变量保存时间,避免了反复调用函数获取时间的性能消耗

 

log = old_cycle->log;

 

从 init_cycle 中继承 log 的相关配置

 

// 创建内存池 16 KB, 16 位对齐 pool = ngx_create_pool(NGX_CYCLE_POOL_SIZE, log); if (pool == NULL) { return NULL; } pool->log = log; // 在内存池中分配空间存储新的 cycle 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;

 

ngx_create_pool

// ngx_pool_t *ngx_create_pool(size_t size, ngx_log_t *log) // 创建内存池 {{{ ngx_pool_t * ngx_create_pool(size_t size, ngx_log_t *log) { ngx_pool_t *p; // 对内存分配函数进行封装,不同系统运行不同的函数 p = ngx_memalign(NGX_POOL_ALIGNMENT, size, log); if (p == NULL) { return NULL; } p->d.last = (u_char *) p + sizeof(ngx_pool_t); p->d.end = (u_char *) p + size; p->d.next = NULL; p->d.failed = 0; // ngx_pool_t 40byte size = size - sizeof(ngx_pool_t); p->max = (size < NGX_MAX_ALLOC_FROM_POOL) ? size : NGX_MAX_ALLOC_FROM_POOL; p->current = p; p->chain = NULL; p->large = NULL; p->cleanup = NULL; p->log = log; return p; } // }}}

 

这个函数我们在内存池初始化中曾经介绍过

但是这里需要注意的是,由于创建内存池时大小参数指定的是 NGX_CYCLE_POOL_SIZE 即 16384,减去 ngx_pool_t 的大小 40B,剩余 16344B,远大于一页的大小 NGX_MAX_ALLOC_FROM_POOL (4095)

因此 pool->max 被设置为 4095

ngx_pcalloc

在内存池中分配内存存储了新的 cycle 变量,这里调用的分配函数是对 ngx_palloc 的封装,主要区别在于他将分配的空间全部初始化为0

// void * ngx_pcalloc(ngx_pool_t *pool, size_t size) // 在内存池中分配空间,并初始化为 0 {{{ void * ngx_pcalloc(ngx_pool_t *pool, size_t size) { void *p; p = ngx_palloc(pool, size); if (p) { ngx_memzero(p, size); } return p; } // }}}

 

// 拷贝配置信息 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;

 

由于在 init_cycle 的初始化过程中已经保存了配置文件的相关信息,所以在 cycle 的初始化中,直接拷贝即可

 

接下的初始化工作还有更加精彩的内容哦,敬请期待下文

 






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