nginx0.1.0之http模块初始化源码分析（3）

/*
     * init http{} main_conf's, merge the server{}s' srv_conf's
     * and its location{}s' loc_conf's
     */
    // 取出ngx_http_core_module在http上下文的main配置 
    cmcf = ctx->main_conf[ngx_http_core_module.ctx_index];
    // server指令的管理结构
    cscfp = cmcf->servers.elts;

    for (m = 0; ngx_modules[m]; m++) {
        if (ngx_modules[m]->type != NGX_HTTP_MODULE) {
            continue;
        }

        module = ngx_modules[m]->ctx;
        mi = ngx_modules[m]->ctx_index;

        /* init http{} main_conf's */
        // ngx_conf_parse没有赋值的字段在这进行初始化
        if (module->init_main_conf) {
            rv = module->init_main_conf(cf, ctx->main_conf[mi]);
            if (rv != NGX_CONF_OK) {
                *cf = pcf;
                return rv;
            }
        }
        // http上下文下所有的server指令对应的结构体数组
        for (s = 0; s < cmcf->servers.nelts; s++) {

            /* merge the server{}s' srv_conf's */

            if (module->merge_srv_conf) {
                // 合并http层和server层配置
                rv = module->merge_srv_conf(cf,
                                            // 子模块在http上下文的srv_conf配置，内容由子模块创建
                                            ctx->srv_conf[mi],
                                            /*
                                                cscfp[s]指向server上下文中的ngx_http_core_srv_conf_t结构体，
                                                通过反向指针找到server指令创建的上下文，再找出某个模块的的srv_conf
                                            */
                                            cscfp[s]->ctx->srv_conf[mi]);
                if (rv != NGX_CONF_OK) {
                    *cf = pcf;
                    return rv;
                }
            }

            if (module->merge_loc_conf) {

                /* merge the server{}'s loc_conf */
                // 合并http层和非嵌套的location层的配置
                rv = module->merge_loc_conf(cf,
                                            ctx->loc_conf[mi],
                                            cscfp[s]->ctx->loc_conf[mi]);
                if (rv != NGX_CONF_OK) {
                    *cf = pcf;
                    return rv;
                }

                /* merge the locations{}' loc_conf's */
                /*
                    合并server和非嵌套location的配置、非嵌套location和嵌套location的配置,
                    &cscfp[s]->locations：server下的所有非嵌套location
                    cscfp[s]->ctx->loc_conf，server层各模块关于location的配置 
                */
                rv = ngx_http_merge_locations(cf, &cscfp[s]->locations,
                                              cscfp[s]->ctx->loc_conf,
                                              module, mi);
                if (rv != NGX_CONF_OK) {
                    *cf = pcf;
                    return rv;
                }
            }
        }
    }

static char *ngx_http_charset_init_main_conf(ngx_conf_t *cf, void *conf)
{
    ngx_http_charset_main_conf_t *mcf = conf;

    ngx_uint_t                  i, n;
    ngx_http_charset_t         *charset;
    ngx_http_charset_tables_t  *tables;

    tables = mcf->tables.elts;
    charset = mcf->charsets.elts;
    // 遍历charset数组
    for (i = 0; i < mcf->charsets.nelts; i++) {
        if (!charset[i].server) {
            continue;
        }

        charset[i].tables = ngx_pcalloc(cf->pool,
                                        sizeof(char *) * mcf->charsets.nelts);

        if (charset[i].tables == NULL) {
            return NGX_CONF_ERROR;
        }

        for (n = 0; n < mcf->tables.nelts; n++) {
            if ((ngx_int_t) i == tables[n].src) {
                charset[i].tables[tables[n].dst] = tables[n].src2dst;
                continue;
            }

            if ((ngx_int_t) i == tables[n].dst) {
                charset[i].tables[tables[n].src] = tables[n].dst2src;
            }
        }
    }
    //校验
    for (i = 0; i < mcf->charsets.nelts; i++) {
        if (!charset[i].server) {
            continue;
        }

        for (n = 0; n < mcf->charsets.nelts; n++) {
            if (i == n) {
                continue;
            }

            if (charset[i].tables[n]) {
                continue;
            }

            ngx_log_error(NGX_LOG_EMERG, cf->log, 0,
                          " no \"charset_map\" between the charsets "
                          "\"%s\" and \"%s\"",
                          charset[i].name.data, charset[n].name.data);
            return NGX_CONF_ERROR;
        }
    }

    return NGX_CONF_OK;
}

static char *ngx_http_core_merge_srv_conf(ngx_conf_t *cf,
                                          void *parent, void *child)
{
    ngx_http_core_srv_conf_t *prev = parent;
    ngx_http_core_srv_conf_t *conf = child;

    ngx_http_listen_t          *l;
    ngx_http_server_name_t     *n;
    ngx_http_core_main_conf_t  *cmcf;

    /* TODO: it does not merge, it inits only */
    // 如果该server没有配置listen指令，则设置默认值
    if (conf->listen.nelts == 0) {
        ngx_test_null(l, ngx_push_array(&conf->listen), NGX_CONF_ERROR);
        // 任何地址进来的连接都可以
        l->addr = INADDR_ANY;
#if (WIN32)
        l->port = 80;
#else
        /* STUB: getuid() should be cached */
        // 等于0说明是root
        l->port = (getuid() == 0) ? 80 : 8000;
#endif
        l->family = AF_INET;
    }
    // 没有配置servername，则取本机主机名
    if (conf->server_names.nelts == 0) {
        ngx_test_null(n, ngx_push_array(&conf->server_names), NGX_CONF_ERROR);
        ngx_test_null(n->name.data, ngx_palloc(cf->pool, NGX_MAXHOSTNAMELEN),
                      NGX_CONF_ERROR);
        // 获取主机名 
        if (gethostname((char *) n->name.data, NGX_MAXHOSTNAMELEN) == -1) {
            ngx_conf_log_error(NGX_LOG_EMERG, cf, ngx_errno,
                               "gethostname() failed");
            return NGX_CONF_ERROR;
        }

        n->name.len = ngx_strlen(n->name.data);
        // 该servername对应的server配置
        n->core_srv_conf = conf;

#if 0
        ctx = (ngx_http_conf_ctx_t *)
                                    cf->cycle->conf_ctx[ngx_http_module.index];
        cmcf = ctx->main_conf[ngx_http_core_module.ctx_index];
#endif
        cmcf = ngx_http_conf_get_module_main_conf(cf, ngx_http_core_module);

        if (cmcf->max_server_name_len < n->name.len) {
            cmcf->max_server_name_len = n->name.len;
        }
    }
    /*
        如果第一个参数没有值，则取第二个参数的，如果第二个参数也没有值，
        则取第三个参数的，即子类没有值，则取父类的，父类也没有值，则取默认的
    */
    ngx_conf_merge_size_value(conf->connection_pool_size,
                              prev->connection_pool_size, 256);
    ngx_conf_merge_msec_value(conf->post_accept_timeout,
                              prev->post_accept_timeout, 60000);
    ngx_conf_merge_size_value(conf->request_pool_size,
                              prev->request_pool_size, 4096);
    ngx_conf_merge_msec_value(conf->client_header_timeout,
                              prev->client_header_timeout, 60000);
    ngx_conf_merge_size_value(conf->client_header_buffer_size,
                              prev->client_header_buffer_size, 1024);
    ngx_conf_merge_bufs_value(conf->large_client_header_buffers,
                              prev->large_client_header_buffers,
                              4, ngx_pagesize);

    if (conf->large_client_header_buffers.size < conf->connection_pool_size) {
        ngx_conf_log_error(NGX_LOG_EMERG, cf, 0,
                           "the \"large_client_header_buffers\" size must be "
                           "equal to or bigger than \"connection_pool_size\"");
        return NGX_CONF_ERROR;
    }

    ngx_conf_merge_unsigned_value(conf->restrict_host_names,
                                  prev->restrict_host_names, 0);

    return NGX_CONF_OK;
}

static char *ngx_http_rewrite_merge_srv_conf(ngx_conf_t *cf,
                                             void *parent, void *child)
{
    ngx_http_rewrite_srv_conf_t *prev = parent;
    ngx_http_rewrite_srv_conf_t *conf = child;

    ngx_conf_merge_value(conf->log, prev->log, 0);

    return NGX_CONF_OK;
}

static char *ngx_http_ssl_merge_srv_conf(ngx_conf_t *cf,
                                         void *parent, void *child)
{
    ngx_http_ssl_srv_conf_t *prev = parent;
    ngx_http_ssl_srv_conf_t *conf = child;

    ngx_conf_merge_value(conf->enable, prev->enable, 0);

    if (conf->enable == 0) {
        return NGX_CONF_OK;
    }
    // server上下文里没有配置证书和私钥则取http上下文的
    ngx_conf_merge_str_value(conf->certificate, prev->certificate,
                             NGX_DEFLAUT_CERTIFICATE);

    ngx_conf_merge_str_value(conf->certificate_key, prev->certificate_key,
                             NGX_DEFLAUT_CERTIFICATE_KEY);

    /* TODO: configure methods */

    conf->ssl_ctx = SSL_CTX_new(SSLv23_server_method());

    if (conf->ssl_ctx == NULL) {
        ngx_ssl_error(NGX_LOG_EMERG, cf->log, 0, "SSL_CTX_new() failed");
        return NGX_CONF_ERROR;
    }
    // 加载用户证书
    if (SSL_CTX_use_certificate_file(conf->ssl_ctx,
                                     (char *) conf->certificate.data,
                                     SSL_FILETYPE_PEM) == 0) {
        ngx_ssl_error(NGX_LOG_EMERG, cf->log, 0,
                      "SSL_CTX_use_certificate_file(\"%s\") failed",
                      conf->certificate.data);
        return NGX_CONF_ERROR;
    }
    // 加载用户私钥
    if (SSL_CTX_use_PrivateKey_file(conf->ssl_ctx,
                                    (char *) conf->certificate_key.data,
                                    SSL_FILETYPE_PEM) == 0) {
        ngx_ssl_error(NGX_LOG_EMERG, cf->log, 0,
                      "SSL_CTX_use_PrivateKey_file(\"%s\") failed",
                      conf->certificate_key.data);
        return NGX_CONF_ERROR;
    }

    return NGX_CONF_OK;
}

static char *ngx_http_access_merge_loc_conf(ngx_conf_t *cf,
                                            void *parent, void *child)
{
    ngx_http_access_loc_conf_t  *prev = parent;
    ngx_http_access_loc_conf_t  *conf = child;
    // 如果location里的配置为空，则取父级的配置
    if (conf->rules == NULL) {
        conf->rules = prev->rules;
    }

    return NGX_CONF_OK;
}

static char *ngx_http_charset_merge_loc_conf(ngx_conf_t *cf,
                                             void *parent, void *child)
{
    ngx_http_charset_loc_conf_t *prev = parent;
    ngx_http_charset_loc_conf_t *conf = child;

    ngx_conf_merge_value(conf->enable, prev->enable, 0);
    ngx_conf_merge_value(conf->autodetect, prev->autodetect, 0);

    if (conf->source_charset == NGX_CONF_UNSET) {
        conf->source_charset = prev->source_charset;
    }

    ngx_conf_merge_value(conf->default_charset, prev->default_charset,
                         conf->source_charset);

    return NGX_CONF_OK;
}

static char *ngx_http_core_merge_loc_conf(ngx_conf_t *cf,
                                          void *parent, void *child)
{
    ngx_http_core_loc_conf_t *prev = parent;
    ngx_http_core_loc_conf_t *conf = child;

    int               i, key;
    ngx_http_type_t  *t;

    ngx_conf_merge_str_value(conf->root, prev->root, "html");

    if (ngx_conf_full_name(cf->cycle, &conf->root) == NGX_ERROR) {
        return NGX_CONF_ERROR;
    }
    // 子层没有配置types
    if (conf->types == NULL) {
        // 父层也没有配置
        if (prev->types) {
            conf->types = prev->types;

        } else {
            // 取默认的
            ngx_test_null(conf->types,
                          ngx_palloc(cf->pool, NGX_HTTP_TYPES_HASH_PRIME
                                                        * sizeof(ngx_array_t)),
                          NGX_CONF_ERROR);
            // 初始化分配的数组
            for (i = 0; i < NGX_HTTP_TYPES_HASH_PRIME; i++) {
                ngx_init_array(conf->types[i], cf->pool,
                               5, sizeof(ngx_http_type_t), NGX_CONF_ERROR);
            }
            // 遍历默认配置
            for (i = 0; default_types[i].exten.len; i++) {
                /*
                    #define ngx_http_types_hash_key(key, ext)                                   \
                    {                                                                   \
                        u_int n;                                                        \
                        for (key = 0, n = 0; n < ext.len; n++) {                        \
                            key += ext.data[n];                                         \
                        }                                                               \
                        key %= NGX_HTTP_TYPES_HASH_PRIME;                               \
                    }
                */
                // 用宏算出数组索引，如果索引一样说明extern一样，则覆盖，这里假设了不会存在html和lmth这样type
                ngx_http_types_hash_key(key, default_types[i].exten);

                ngx_test_null(t, ngx_push_array(&conf->types[key]),
                              NGX_CONF_ERROR);
                t->exten.len = default_types[i].exten.len;
                t->exten.data = default_types[i].exten.data;
                t->type.len = default_types[i].type.len;
                t->type.data = default_types[i].type.data;
            }
        }
    }

    if (conf->err_log == NULL) {
        if (prev->err_log) {
            conf->err_log = prev->err_log;
        } else {
            conf->err_log = cf->cycle->new_log;
        }
    }

    if (conf->error_pages == NULL && prev->error_pages) {
        conf->error_pages = prev->error_pages;
    }

    ngx_conf_merge_str_value(conf->default_type,
                             prev->default_type, "text/plain");

    ngx_conf_merge_size_value(conf->client_max_body_size,
                              prev->client_max_body_size, 1 * 1024 * 1024);
    ngx_conf_merge_size_value(conf->client_body_buffer_size,
                              prev->client_body_buffer_size,
                              (size_t) 2 * ngx_pagesize);
    ngx_conf_merge_msec_value(conf->client_body_timeout,
                              prev->client_body_timeout, 60000);
    ngx_conf_merge_value(conf->sendfile, prev->sendfile, 0);
    ngx_conf_merge_value(conf->tcp_nopush, prev->tcp_nopush, 0);
    ngx_conf_merge_msec_value(conf->send_timeout, prev->send_timeout, 60000);
    ngx_conf_merge_size_value(conf->send_lowat, prev->send_lowat, 0);
    ngx_conf_merge_size_value(conf->postpone_output, prev->postpone_output,
                              1460);
    ngx_conf_merge_size_value(conf->limit_rate, prev->limit_rate, 0);
    ngx_conf_merge_msec_value(conf->keepalive_timeout,
                              prev->keepalive_timeout, 75000);
    ngx_conf_merge_sec_value(conf->keepalive_header,
                              prev->keepalive_header, 0);
    ngx_conf_merge_msec_value(conf->lingering_time,
                              prev->lingering_time, 30000);
    ngx_conf_merge_msec_value(conf->lingering_timeout,
                              prev->lingering_timeout, 5000);

    ngx_conf_merge_value(conf->reset_timedout_connection,
                         prev->reset_timedout_connection, 0);
    ngx_conf_merge_value(conf->msie_padding, prev->msie_padding, 1);

    if (conf->open_files == NULL) {
        conf->open_files = prev->open_files;
    }

    return NGX_CONF_OK;
}

static char *ngx_http_merge_locations(ngx_conf_t *cf,
                                      ngx_array_t *locations,
                                      void **loc_conf,
                                      ngx_http_module_t *module,
                                      ngx_uint_t ctx_index)
{
    char                       *rv;
    ngx_uint_t                  i;
    ngx_http_core_loc_conf_t  **clcfp;

    clcfp = /* (ngx_http_core_loc_conf_t **) */ locations->elts;
    // 遍历父层的location
    for (i = 0; i < locations->nelts; i++) {
        /* 
            先合并server和非嵌套location层的配置
            loc_conf[ctx_index]:server层的location配置,
            clcfp[i]->loc_conf[ctx_index]:location层各模块的配置
        */
        rv = module->merge_loc_conf(cf, loc_conf[ctx_index],
                                    clcfp[i]->loc_conf[ctx_index]);
        if (rv != NGX_CONF_OK) {
            return rv;
        }
        /*
          再合并嵌套location和非嵌套location的配置, 
          &clcfp[i]->locations：各模块关于嵌套的lcaotion，
          clcfp[i]->loc_conf：各模块和关于非嵌套location的配置
        */
        rv = ngx_http_merge_locations(cf, &clcfp[i]->locations,
                                      clcfp[i]->loc_conf, module, ctx_index);
        if (rv != NGX_CONF_OK) {
            return rv;
        }
    }

    return NGX_CONF_OK;
}