nginx0.1.0之event模块初始化源码分析(3)

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前面已经分析了event初始化的整体流程和第一步create_conf，接下来看一下第二步ngx_conf_parse。这里不分析该函数的代码，该函数主要是遍历配置文件的内容，然后读取命令和参数。最后匹配nginx所有模块的配置，找到处理该指令的函数。我们首先看一下event模块中ngx_event_core_module模块的指令配置。

static ngx_command_t  ngx_event_core_commands[] = {{ ngx_string("connections"),NGX_EVENT_CONF|NGX_CONF_TAKE1,ngx_event_connections,0,0,NULL },{ ngx_string("use"),NGX_EVENT_CONF|NGX_CONF_TAKE1,ngx_event_use,0,0,NULL },{ ngx_string("multi_accept"),NGX_EVENT_CONF|NGX_CONF_TAKE1,ngx_conf_set_flag_slot,0,offsetof(ngx_event_conf_t, multi_accept),NULL },{ ngx_string("accept_mutex"),NGX_EVENT_CONF|NGX_CONF_TAKE1,ngx_conf_set_flag_slot,0,offsetof(ngx_event_conf_t, accept_mutex),&ngx_accept_mutex_post },{ ngx_string("accept_mutex_delay"),NGX_EVENT_CONF|NGX_CONF_TAKE1,ngx_conf_set_msec_slot,0,offsetof(ngx_event_conf_t, accept_mutex_delay),NULL },{ ngx_string("debug_connection"),NGX_EVENT_CONF|NGX_CONF_TAKE1,ngx_event_debug_connection,0,0,NULL },ngx_null_command
}

然后在看一下每个指令处理函数的代码。

connections指令

//把连接数记录在结构体中
static char *ngx_event_connections(ngx_conf_t *cf, ngx_command_t *cmd,void *conf)
{ngx_event_conf_t  *ecf = conf;ngx_str_t  *value;// 已经初始化过了if (ecf->connections != NGX_CONF_UNSET_UINT) {return "is duplicate" ;}// 从配置文件中解析出来的配置value = cf->args->elts;// 字符串转成整形ecf->connections = ngx_atoi(value[1].data, value[1].len);if (ecf->connections == (ngx_uint_t) NGX_ERROR) {ngx_conf_log_error(NGX_LOG_EMERG, cf, 0,"invalid number \"%s\"", value[1].data);return NGX_CONF_ERROR;}cf->cycle->connection_n = ecf->connections;return NGX_CONF_OK;
}

use指令

// 记录use和name的值
static char *ngx_event_use(ngx_conf_t *cf, ngx_command_t *cmd, void *conf)
{ngx_event_conf_t  *ecf = conf;ngx_int_t             m;ngx_str_t            *value;ngx_event_conf_t     *old_ecf;ngx_event_module_t   *module;if (ecf->use != NGX_CONF_UNSET_UINT) {return "is duplicate" ;}value = cf->args->elts;if (cf->cycle->old_cycle->conf_ctx) {old_ecf = ngx_event_get_conf(cf->cycle->old_cycle->conf_ctx,ngx_event_core_module);} else {old_ecf = NULL;}// 判断使用哪个事件驱动模块，比如use epoll，则使用epollfor (m = 0; ngx_modules[m]; m++) {if (ngx_modules[m]->type != NGX_EVENT_MODULE) {continue;}module = ngx_modules[m]->ctx;if (module->name->len == value[1].len) {if (ngx_strcmp(module->name->data, value[1].data) == 0) {// 存储事件模块的下标,而不是字符串ecf->use = ngx_modules[m]->ctx_index;ecf->name = module->name->data;if (ngx_process == NGX_PROCESS_SINGLE&& old_ecf&& old_ecf->use != ecf->use){ngx_conf_log_error(NGX_LOG_EMERG, cf, 0,"when the server runs without a master process ""the \"%s\" event type must be the same as ""in previous configuration - \"%s\" ""and it can not be changed on the fly, ""to change it you need to stop server ""and start it again",value[1].data, old_ecf->name);return NGX_CONF_ERROR;}return NGX_CONF_OK;}}}ngx_conf_log_error(NGX_LOG_EMERG, cf, 0,"invalid event type \"%s\"", value[1].data);return NGX_CONF_ERROR;
}

multi_accept指令

char *ngx_conf_set_flag_slot(ngx_conf_t *cf, ngx_command_t *cmd, void *conf)
{char  *p = conf;ngx_str_t        *value;ngx_flag_t       *fp;ngx_conf_post_t  *post;fp = (ngx_flag_t *) (p + cmd->offset);if (*fp != NGX_CONF_UNSET) {return "is duplicate";}value = cf->args->elts;// on代表开启if (ngx_strcasecmp(value[1].data, "on") == 0) {*fp = 1;} else if (ngx_strcasecmp(value[1].data, "off") == 0) {*fp = 0;} else {ngx_conf_log_error(NGX_LOG_EMERG, cf, 0,"invalid value \"%s\" in \"%s\" directive, ""it must be \"on\" or \"off\"",value[1].data, cmd->name.data);return NGX_CONF_ERROR;}// 设置完值后执行后置函数，一般是参数检查if (cmd->post) {post = cmd->post;return post->post_handler(cf, post, fp);}return NGX_CONF_OK;
}

accept_mutex指令（见上面的ngx_conf_set_flag_slot函数）

该指令配置了handle函数
ngx_conf_post_t  ngx_accept_mutex_post = { ngx_accept_mutex_check } 
static char *ngx_accept_mutex_check(ngx_conf_t *cf, void *post, void *data)
{
// 不支持该功能，重置字段
#if !(NGX_HAVE_ATOMIC_OPS)ngx_flag_t *fp = data;*fp = 0;ngx_conf_log_error(NGX_LOG_WARN, cf, 0,"\"accept_mutex\" is not supported, ignored");#endifreturn NGX_CONF_OK;
}

accept_mutex_delay指令

char *ngx_conf_set_msec_slot(ngx_conf_t *cf, ngx_command_t *cmd, void *conf)
{char  *p = conf;ngx_msec_t       *msp;ngx_str_t        *value;ngx_conf_post_t  *post;msp = (ngx_msec_t *) (p + cmd->offset);if (*msp != NGX_CONF_UNSET_MSEC) {return "is duplicate";}value = cf->args->elts;// 把字符串解析成时间*msp = ngx_parse_time(&value[1], 0);if (*msp == (ngx_msec_t) NGX_ERROR) {return "invalid value";}if (*msp == (ngx_msec_t) NGX_PARSE_LARGE_TIME) {return "value must be less than 597 hours";}if (cmd->post) {post = cmd->post;return post->post_handler(cf, post, msp);}return NGX_CONF_OK;
}

debug_connection指令

static char *ngx_event_debug_connection(ngx_conf_t *cf, ngx_command_t *cmd,void *conf)
{
// 配置后需要开启debug参数
#if (NGX_DEBUG)ngx_event_conf_t  *ecf = conf;in_addr_t       *addr;ngx_str_t       *value;struct hostent  *h;value = cf->args->elts;/* AF_INET only */if (!(addr = ngx_push_array(&ecf->debug_connection))) {return NGX_CONF_ERROR;}// 将ip转成长整型*addr = inet_addr((char *) value[1].data);// 转成功则返回if (*addr != INADDR_NONE) {return NGX_OK;}// 没转成功可能是一个主机字符串，获取该主机对应的ip信息h = gethostbyname((char *) value[1].data);if (h == NULL || h->h_addr_list[0] == NULL) {ngx_conf_log_error(NGX_LOG_EMERG, cf, 0,"host %s not found", value[1].data);return NGX_CONF_ERROR;
}*addr = *(in_addr_t *)(h->h_addr_list[0]);#elsengx_conf_log_error(NGX_LOG_WARN, cf, 0,"\"debug_connection\" is ignored, you need to rebuild ""nginx using --with-debug option to enable it");#endifreturn NGX_OK;
}