Nginx(四):http服务器静态文件查找的实现

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2021-01-19 08:14

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上一篇nginx的文章中,我们理解了整个http正向代理的运行流程原理,主要就是事件机制接入,header解析,body解析,然后遍历各种checker,直到处理成功为止。

我们以访问一个普通文件为例,nginx到底是如何找到这个文件并返回信息的呢?它会不会有些什么限制呢?

按我们自己的理解,它应该是uri栏里截取出相应的路径,然后对应到root下,查找到相应文件,返回即可。那么,它又是如何处理html和其他的各种不同格式的文件呢?

就让我们一起来探秘nginx文件的查找实现吧!

0. nginx 静态文件配置

要配置静态文件处理,只需在http server中配置root路径即可。(当然了,你可以根据前缀配置许多不同的root)

http {    include       mime.types;    default_type  application/octet-stream;
#log_format main '$remote_addr - $remote_user [$time_local] "$request" ' # '$status $body_bytes_sent "$http_referer" ' # '"$http_user_agent" "$http_x_forwarded_for"';
#access_log logs/access.log main;
sendfile on; #tcp_nopush on;
#keepalive_timeout 0; keepalive_timeout 65;
#gzip on;
server { listen 8085; server_name localhost;
#charset koi8-r;
#access_log logs/host.access.log main;
location /hello { root /www/hello; index index.html index.htm; }
location / { root html; index index.html index.htm; } } # 后续可以添加无数个server 扩展}


配置简单吧,实际核心就两三行代码搞定:监听端口号 listen、访问域名 server_name、服务器根路径 root。明显这是nginx成功的原因之一。

本文要讨论的场景是,如果我访问 http://localhost:8085/1.txt?d=xxx, nginx将如何干成这件事?

1. checker的遍历回顾

我们先来回顾下,nginx是如何遍历各个checker的吧!

// http/ngx_http_core_module.c// 响应客户端操作, 多阶段式操作voidngx_http_core_run_phases(ngx_http_request_t *r){    ngx_int_t                   rc;    ngx_http_phase_handler_t   *ph;    ngx_http_core_main_conf_t  *cmcf;
cmcf = ngx_http_get_module_main_conf(r, ngx_http_core_module);
ph = cmcf->phase_engine.handlers; // 依次调用各 checker, 直到有响应 OK 的checker为止 while (ph[r->phase_handler].checker) { // 每次调用 checker 之后, 内部都会将 r->phase_handler++, 即迭代下一个 // 此处的 checker 非常之多, 是在各模块启动时, 自动向 ngx_http_core_module.main_conf 中进行注册的 /** * 定义如下: typedef enum { NGX_HTTP_POST_READ_PHASE = 0,
NGX_HTTP_SERVER_REWRITE_PHASE,
NGX_HTTP_FIND_CONFIG_PHASE, NGX_HTTP_REWRITE_PHASE, NGX_HTTP_POST_REWRITE_PHASE,
NGX_HTTP_PREACCESS_PHASE,
NGX_HTTP_ACCESS_PHASE, NGX_HTTP_POST_ACCESS_PHASE,
NGX_HTTP_PRECONTENT_PHASE,
NGX_HTTP_CONTENT_PHASE,
NGX_HTTP_LOG_PHASE } ngx_http_phases;
// 注册方式 cmcf = ngx_http_conf_get_module_main_conf(cf, ngx_http_core_module); h = ngx_array_push(&cmcf->phases[NGX_HTTP_ACCESS_PHASE].handlers); *h = ngx_http_access_handler; */ // 将请求信息和 handler 本身传入调用(不是面向, 只能这么做了) rc = ph[r->phase_handler].checker(r, &ph[r->phase_handler]); // 只要有一个处理成功, 则后续不再调用 if (rc == NGX_OK) { return; } }}


可以说,它的各checker是非常复杂的,各模块都可以向其中注册处理器。这也是nginx灵活性的体现。不过我们不想关注太多。

文件的查找是在 static_module 中完成的,我们只需关注这个即可。

2. 静态文件模块的注册

静态文件模块主要就是负责静态文件的查找处理。几乎所有的http处理模块,都是先进行注册,然后再被调用的过程。static_module 自然不例外。

// http/modules/ngx_http_static_handler.c    static ngx_int_tngx_http_static_init(ngx_conf_t *cf){    ngx_http_handler_pt        *h;    ngx_http_core_main_conf_t  *cmcf;
cmcf = ngx_http_conf_get_module_main_conf(cf, ngx_http_core_module); // 获取http_core_module的配置 // 将ngx_http_static_handler 添加到 NGX_HTTP_CONTENT_PHASE 的handlers中 h = ngx_array_push(&cmcf->phases[NGX_HTTP_CONTENT_PHASE].handlers); if (h == NULL) { return NGX_ERROR; }
*h = ngx_http_static_handler;
return NGX_OK;}
// 下面是一些nginx的模块暴露规范,只有这样,这个模块才会被接入到整个系统中static ngx_http_module_t ngx_http_static_module_ctx = { NULL, /* preconfiguration */ ngx_http_static_init, /* postconfiguration */
NULL, /* create main configuration */ NULL, /* init main configuration */
NULL, /* create server configuration */ NULL, /* merge server configuration */
NULL, /* create location configuration */ NULL /* merge location configuration */};

ngx_module_t ngx_http_static_module = { NGX_MODULE_V1, &ngx_http_static_module_ctx, /* module context */ NULL, /* module directives */ NGX_HTTP_MODULE, /* module type */ NULL, /* init master */ NULL, /* init module */ NULL, /* init process */ NULL, /* init thread */ NULL, /* exit thread */ NULL, /* exit process */ NULL, /* exit master */ NGX_MODULE_V1_PADDING};

3. 文件查找实现

经过前面的模块注册到 NGX_HTTP_CONTENT_PHASE 中,就会被nginx调用。前提是没有其他更合适的处理器的时候。而因为 static_module 是在 NGX_HTTP_CONTENT_PHASE 中,所以都会走content的处理器:

// http/ngx_http_core_module.c    ngx_int_tngx_http_core_content_phase(ngx_http_request_t *r,    ngx_http_phase_handler_t *ph){    size_t     root;    ngx_int_t  rc;    ngx_str_t  path;
if (r->content_handler) { r->write_event_handler = ngx_http_request_empty_handler; ngx_http_finalize_request(r, r->content_handler(r)); return NGX_OK; }
ngx_log_debug1(NGX_LOG_DEBUG_HTTP, r->connection->log, 0, "content phase: %ui", r->phase_handler);
rc = ph->handler(r); // 处理成功,则返回ok if (rc != NGX_DECLINED) { ngx_http_finalize_request(r, rc); return NGX_OK; }
/* rc == NGX_DECLINED */
ph++;
if (ph->checker) { r->phase_handler++; return NGX_AGAIN; }
/* no content handler was found */
if (r->uri.data[r->uri.len - 1] == '/') {
if (ngx_http_map_uri_to_path(r, &path, &root, 0) != NULL) { ngx_log_error(NGX_LOG_ERR, r->connection->log, 0, "directory index of \"%s\" is forbidden", path.data); }
ngx_http_finalize_request(r, NGX_HTTP_FORBIDDEN); return NGX_OK; }
ngx_log_error(NGX_LOG_ERR, r->connection->log, 0, "no handler found");
ngx_http_finalize_request(r, NGX_HTTP_NOT_FOUND); return NGX_OK;}

// http/modules/ngx_http_static_handler.cstatic ngx_int_tngx_http_static_handler(ngx_http_request_t *r){ u_char *last, *location; size_t root, len; ngx_str_t path; ngx_int_t rc; ngx_uint_t level; ngx_log_t *log; ngx_buf_t *b; ngx_chain_t out; ngx_open_file_info_t of; ngx_http_core_loc_conf_t *clcf; // 仅支持 get/head/post 方法进行静态文件处理 if (!(r->method & (NGX_HTTP_GET|NGX_HTTP_HEAD|NGX_HTTP_POST))) { return NGX_HTTP_NOT_ALLOWED; } // 要求uri不能以'/'结尾,否则走其他协议 if (r->uri.data[r->uri.len - 1] == '/') { return NGX_DECLINED; }
log = r->connection->log;
/* * ngx_http_map_uri_to_path() allocates memory for terminating '\0' * so we do not need to reserve memory for '/' for possible redirect */ // 解析文件路径到path中 last = ngx_http_map_uri_to_path(r, &path, &root, 0); if (last == NULL) { return NGX_HTTP_INTERNAL_SERVER_ERROR; }
path.len = last - path.data;
ngx_log_debug1(NGX_LOG_DEBUG_HTTP, log, 0, "http filename: \"%s\"", path.data);
clcf = ngx_http_get_module_loc_conf(r, ngx_http_core_module); // 初始化文件实例 ngx_memzero(&of, sizeof(ngx_open_file_info_t));
of.read_ahead = clcf->read_ahead; of.directio = clcf->directio; of.valid = clcf->open_file_cache_valid; of.min_uses = clcf->open_file_cache_min_uses; of.errors = clcf->open_file_cache_errors; of.events = clcf->open_file_cache_events;
if (ngx_http_set_disable_symlinks(r, clcf, &path, &of) != NGX_OK) { return NGX_HTTP_INTERNAL_SERVER_ERROR; }
if (ngx_open_cached_file(clcf->open_file_cache, &path, &of, r->pool) != NGX_OK) { switch (of.err) {
case 0: return NGX_HTTP_INTERNAL_SERVER_ERROR;
case NGX_ENOENT: case NGX_ENOTDIR: case NGX_ENAMETOOLONG:
level = NGX_LOG_ERR; rc = NGX_HTTP_NOT_FOUND; break;
case NGX_EACCES:#if (NGX_HAVE_OPENAT) case NGX_EMLINK: case NGX_ELOOP:#endif
level = NGX_LOG_ERR; rc = NGX_HTTP_FORBIDDEN; break;
default:
level = NGX_LOG_CRIT; rc = NGX_HTTP_INTERNAL_SERVER_ERROR; break; }
if (rc != NGX_HTTP_NOT_FOUND || clcf->log_not_found) { ngx_log_error(level, log, of.err, "%s \"%s\" failed", of.failed, path.data); }
return rc; }
r->root_tested = !r->error_page;
ngx_log_debug1(NGX_LOG_DEBUG_HTTP, log, 0, "http static fd: %d", of.fd);
if (of.is_dir) {
ngx_log_debug0(NGX_LOG_DEBUG_HTTP, log, 0, "http dir");
ngx_http_clear_location(r);
r->headers_out.location = ngx_list_push(&r->headers_out.headers); if (r->headers_out.location == NULL) { return NGX_HTTP_INTERNAL_SERVER_ERROR; }
len = r->uri.len + 1;
if (!clcf->alias && r->args.len == 0) { location = path.data + root;
*last = '/';
} else { if (r->args.len) { len += r->args.len + 1; }
location = ngx_pnalloc(r->pool, len); if (location == NULL) { ngx_http_clear_location(r); return NGX_HTTP_INTERNAL_SERVER_ERROR; }
last = ngx_copy(location, r->uri.data, r->uri.len);
*last = '/';
if (r->args.len) { *++last = '?'; ngx_memcpy(++last, r->args.data, r->args.len); } }
r->headers_out.location->hash = 1; ngx_str_set(&r->headers_out.location->key, "Location"); r->headers_out.location->value.len = len; r->headers_out.location->value.data = location;
return NGX_HTTP_MOVED_PERMANENTLY; }
#if !(NGX_WIN32) /* the not regular files are probably Unix specific */
if (!of.is_file) { ngx_log_error(NGX_LOG_CRIT, log, 0, "\"%s\" is not a regular file", path.data);
return NGX_HTTP_NOT_FOUND; }
#endif // 真正到内容输出的时候,post又是不被允许的方法 if (r->method == NGX_HTTP_POST) { return NGX_HTTP_NOT_ALLOWED; } // 静态文件处理,将会忽略所有请求body参数 rc = ngx_http_discard_request_body(r);
if (rc != NGX_OK) { return rc; } // 输出文件内容到客户端 log->action = "sending response to client";
r->headers_out.status = NGX_HTTP_OK; r->headers_out.content_length_n = of.size; r->headers_out.last_modified_time = of.mtime; // 设置 ETag header if (ngx_http_set_etag(r) != NGX_OK) { return NGX_HTTP_INTERNAL_SERVER_ERROR; } // content-type 设置,大概就是根据文件后缀找到相应的content-type 输出即可 if (ngx_http_set_content_type(r) != NGX_OK) { return NGX_HTTP_INTERNAL_SERVER_ERROR; }
if (r != r->main && of.size == 0) { return ngx_http_send_header(r); }
r->allow_ranges = 1;
/* we need to allocate all before the header would be sent */
b = ngx_calloc_buf(r->pool); if (b == NULL) { return NGX_HTTP_INTERNAL_SERVER_ERROR; }
b->file = ngx_pcalloc(r->pool, sizeof(ngx_file_t)); if (b->file == NULL) { return NGX_HTTP_INTERNAL_SERVER_ERROR; } // 发送头信息,如果是 head 请求,则到此为止 // 该header响应会添加一些公共的请求头一并返回   // 其中content-type是根据文件类型做的映射返回,如txt文件映射为 text/plain   // 具体可以由用户指定,在 mime.types 中添加映射即可 // 使用一系列的filter过滤器链进行处理 // 当文件未发生变化时,会返回304, 即不再返回更多信息 /** Accept-Ranges: bytes Connection: keep-alive Content-Length: 18 Content-Type: text/plain Date: Wed, 07 Oct 2020 09:01:12 GMT ETag: "5f66fc46-12" Last-Modified: Sun, 20 Sep 2020 06:52:54 GMT Server: nginx/1.19.2 */ rc = ngx_http_send_header(r);
if (rc == NGX_ERROR || rc > NGX_OK || r->header_only) { return rc; } // 封装要响应的文件描述符,输出响应 b->file_pos = 0; b->file_last = of.size;
b->in_file = b->file_last ? 1: 0; b->last_buf = (r == r->main) ? 1: 0; b->last_in_chain = 1;
b->file->fd = of.fd; b->file->name = path; b->file->log = log; b->file->directio = of.is_directio;
out.buf = b; out.next = NULL; // 一系列的响应过滤器处理,响应body /** * range_filter * copy_filter * output_chain -> output_chain_copy_buf */ return ngx_http_output_filter(r, &out);}


整体可以简单用一句话说明,根据uri路径,结合root路径配置,得到文件信息,响应客户端。只处理 get/head请求,对文件内容无变化情况将会返回304。上面更多的是,只限于c语言的表达能力问题,做的许多变化,无须多看。

对于静态文件的处理,后续所有给定的参数都将被忽略掉。当然了也不是完全无用,不同参数也是有意义的,它用于检测文件是否发生变化。至于是html文件还是pdf或者txt,nginx并没有做特别的处理,它只是负责将内容返回给浏览器,浏览器做进一步解析从而达到html展现的效果。

另外,再次需要说明的一点是,nginx的性能优势是在于其巧妙地利用系统的非阻塞io,从而提升了处理能力,而且其扩展能力非常强,配置也非常友好。但其整体流程,与其他http服务器并无二致。

对于想要了解更多细节的同学,可以点开下面的代码,查看C语言的实现细节。

// http/ngx_http_core_module.c// 解析文件路径到path中u_char *ngx_http_map_uri_to_path(ngx_http_request_t *r, ngx_str_t *path,    size_t *root_length, size_t reserved){    u_char                    *last;    size_t                     alias;    ngx_http_core_loc_conf_t  *clcf;
clcf = ngx_http_get_module_loc_conf(r, ngx_http_core_module);
alias = clcf->alias;
if (alias && !r->valid_location) { ngx_log_error(NGX_LOG_ALERT, r->connection->log, 0, "\"alias\" cannot be used in location \"%V\" " "where URI was rewritten", &clcf->name); return NULL; }
if (clcf->root_lengths == NULL) {
*root_length = clcf->root.len;
path->len = clcf->root.len + reserved + r->uri.len - alias + 1;
path->data = ngx_pnalloc(r->pool, path->len); if (path->data == NULL) { return NULL; } // 将root根目录赋值给 path last = ngx_copy(path->data, clcf->root.data, clcf->root.len);
} else {
if (alias == NGX_MAX_SIZE_T_VALUE) { reserved += r->add_uri_to_alias ? r->uri.len + 1 : 1;
} else { reserved += r->uri.len - alias + 1; }
if (ngx_http_script_run(r, path, clcf->root_lengths->elts, reserved, clcf->root_values->elts) == NULL) { return NULL; }
if (ngx_get_full_name(r->pool, (ngx_str_t *) &ngx_cycle->prefix, path) != NGX_OK) { return NULL; }
*root_length = path->len - reserved; last = path->data + *root_length;
if (alias == NGX_MAX_SIZE_T_VALUE) { if (!r->add_uri_to_alias) { *last = '\0'; return last; }
alias = 0; } } // 将uri的相对路径拼接到 path 中 last = ngx_copy(last, r->uri.data + alias, r->uri.len - alias); *last = '\0';
return last;}
// http/ngx_http_core_module.cngx_int_tngx_http_set_disable_symlinks(ngx_http_request_t *r, ngx_http_core_loc_conf_t *clcf, ngx_str_t *path, ngx_open_file_info_t *of){#if (NGX_HAVE_OPENAT) u_char *p; ngx_str_t from;
of->disable_symlinks = clcf->disable_symlinks;
if (clcf->disable_symlinks_from == NULL) { return NGX_OK; }
if (ngx_http_complex_value(r, clcf->disable_symlinks_from, &from) != NGX_OK) { return NGX_ERROR; }
if (from.len == 0 || from.len > path->len || ngx_memcmp(path->data, from.data, from.len) != 0) { return NGX_OK; }
if (from.len == path->len) { of->disable_symlinks = NGX_DISABLE_SYMLINKS_OFF; return NGX_OK; }
p = path->data + from.len;
if (*p == '/') { of->disable_symlinks_from = from.len; return NGX_OK; }
p--;
if (*p == '/') { of->disable_symlinks_from = from.len - 1; }#endif
return NGX_OK;}

// core/ngx_open_file_cache.c// 尝试使用缓存文件ngx_int_tngx_open_cached_file(ngx_open_file_cache_t *cache, ngx_str_t *name, ngx_open_file_info_t *of, ngx_pool_t *pool){ time_t now; uint32_t hash; ngx_int_t rc; ngx_file_info_t fi; ngx_pool_cleanup_t *cln; ngx_cached_open_file_t *file; ngx_pool_cleanup_file_t *clnf; ngx_open_file_cache_cleanup_t *ofcln;
of->fd = NGX_INVALID_FILE; of->err = 0; // 没有缓存,则重新打开文件 if (cache == NULL) {
if (of->test_only) {
if (ngx_file_info_wrapper(name, of, &fi, pool->log) == NGX_FILE_ERROR) { return NGX_ERROR; }
of->uniq = ngx_file_uniq(&fi); of->mtime = ngx_file_mtime(&fi); of->size = ngx_file_size(&fi); of->fs_size = ngx_file_fs_size(&fi); of->is_dir = ngx_is_dir(&fi); of->is_file = ngx_is_file(&fi); of->is_link = ngx_is_link(&fi); of->is_exec = ngx_is_exec(&fi);
return NGX_OK; }
cln = ngx_pool_cleanup_add(pool, sizeof(ngx_pool_cleanup_file_t)); if (cln == NULL) { return NGX_ERROR; } // 打开文件 rc = ngx_open_and_stat_file(name, of, pool->log); // 找到对应文件,设置 handler 为 ngx_pool_cleanup_file if (rc == NGX_OK && !of->is_dir) { cln->handler = ngx_pool_cleanup_file; clnf = cln->data;
clnf->fd = of->fd; clnf->name = name->data; clnf->log = pool->log; }
return rc; }
cln = ngx_pool_cleanup_add(pool, sizeof(ngx_open_file_cache_cleanup_t)); if (cln == NULL) { return NGX_ERROR; }
now = ngx_time();
hash = ngx_crc32_long(name->data, name->len);
file = ngx_open_file_lookup(cache, name, hash);
if (file) {
file->uses++;
ngx_queue_remove(&file->queue);
if (file->fd == NGX_INVALID_FILE && file->err == 0 && !file->is_dir) {
/* file was not used often enough to keep open */
rc = ngx_open_and_stat_file(name, of, pool->log);
if (rc != NGX_OK && (of->err == 0 || !of->errors)) { goto failed; }
goto add_event; }
if (file->use_event || (file->event == NULL && (of->uniq == 0 || of->uniq == file->uniq) && now - file->created < of->valid#if (NGX_HAVE_OPENAT) && of->disable_symlinks == file->disable_symlinks && of->disable_symlinks_from == file->disable_symlinks_from#endif )) { if (file->err == 0) {
of->fd = file->fd; of->uniq = file->uniq; of->mtime = file->mtime; of->size = file->size;
of->is_dir = file->is_dir; of->is_file = file->is_file; of->is_link = file->is_link; of->is_exec = file->is_exec; of->is_directio = file->is_directio;
if (!file->is_dir) { file->count++; ngx_open_file_add_event(cache, file, of, pool->log); }
} else { of->err = file->err;#if (NGX_HAVE_OPENAT) of->failed = file->disable_symlinks ? ngx_openat_file_n : ngx_open_file_n;#else of->failed = ngx_open_file_n;#endif }
goto found; }
ngx_log_debug4(NGX_LOG_DEBUG_CORE, pool->log, 0, "retest open file: %s, fd:%d, c:%d, e:%d", file->name, file->fd, file->count, file->err);
if (file->is_dir) {
/* * chances that directory became file are very small * so test_dir flag allows to use a single syscall * in ngx_file_info() instead of three syscalls */
of->test_dir = 1; }
of->fd = file->fd; of->uniq = file->uniq;
rc = ngx_open_and_stat_file(name, of, pool->log);
if (rc != NGX_OK && (of->err == 0 || !of->errors)) { goto failed; }
if (of->is_dir) {
if (file->is_dir || file->err) { goto update; }
/* file became directory */
} else if (of->err == 0) { /* file */
if (file->is_dir || file->err) { goto add_event; }
if (of->uniq == file->uniq) {
if (file->event) { file->use_event = 1; }
of->is_directio = file->is_directio;
goto update; }
/* file was changed */
} else { /* error to cache */
if (file->err || file->is_dir) { goto update; }
/* file was removed, etc. */ }
if (file->count == 0) {
ngx_open_file_del_event(file);
if (ngx_close_file(file->fd) == NGX_FILE_ERROR) { ngx_log_error(NGX_LOG_ALERT, pool->log, ngx_errno, ngx_close_file_n " \"%V\" failed", name); }
goto add_event; }
ngx_rbtree_delete(&cache->rbtree, &file->node);
cache->current--;
file->close = 1;
goto create; }
/* not found */
rc = ngx_open_and_stat_file(name, of, pool->log);
if (rc != NGX_OK && (of->err == 0 || !of->errors)) { goto failed; }
create:
if (cache->current >= cache->max) { ngx_expire_old_cached_files(cache, 0, pool->log); }
file = ngx_alloc(sizeof(ngx_cached_open_file_t), pool->log);
if (file == NULL) { goto failed; }
file->name = ngx_alloc(name->len + 1, pool->log);
if (file->name == NULL) { ngx_free(file); file = NULL; goto failed; }
ngx_cpystrn(file->name, name->data, name->len + 1);
file->node.key = hash;
ngx_rbtree_insert(&cache->rbtree, &file->node);
cache->current++;
file->uses = 1; file->count = 0; file->use_event = 0; file->event = NULL;
add_event:
ngx_open_file_add_event(cache, file, of, pool->log);
update:
file->fd = of->fd; file->err = of->err;#if (NGX_HAVE_OPENAT) file->disable_symlinks = of->disable_symlinks; file->disable_symlinks_from = of->disable_symlinks_from;#endif
if (of->err == 0) { file->uniq = of->uniq; file->mtime = of->mtime; file->size = of->size;
file->close = 0;
file->is_dir = of->is_dir; file->is_file = of->is_file; file->is_link = of->is_link; file->is_exec = of->is_exec; file->is_directio = of->is_directio;
if (!of->is_dir) { file->count++; } }
file->created = now;
found:
file->accessed = now;
ngx_queue_insert_head(&cache->expire_queue, &file->queue);
ngx_log_debug5(NGX_LOG_DEBUG_CORE, pool->log, 0, "cached open file: %s, fd:%d, c:%d, e:%d, u:%d", file->name, file->fd, file->count, file->err, file->uses);
if (of->err == 0) {
if (!of->is_dir) { cln->handler = ngx_open_file_cleanup; ofcln = cln->data;
ofcln->cache = cache; ofcln->file = file; ofcln->min_uses = of->min_uses; ofcln->log = pool->log; }
return NGX_OK; }
return NGX_ERROR;
failed:
if (file) { ngx_rbtree_delete(&cache->rbtree, &file->node);
cache->current--;
if (file->count == 0) {
if (file->fd != NGX_INVALID_FILE) { if (ngx_close_file(file->fd) == NGX_FILE_ERROR) { ngx_log_error(NGX_LOG_ALERT, pool->log, ngx_errno, ngx_close_file_n " \"%s\" failed", file->name); } }
ngx_free(file->name); ngx_free(file);
} else { file->close = 1; } }
if (of->fd != NGX_INVALID_FILE) { if (ngx_close_file(of->fd) == NGX_FILE_ERROR) { ngx_log_error(NGX_LOG_ALERT, pool->log, ngx_errno, ngx_close_file_n " \"%V\" failed", name); } }
return NGX_ERROR;}
// core/ngx_open_file_cache.c// 打开文件static ngx_int_tngx_open_and_stat_file(ngx_str_t *name, ngx_open_file_info_t *of, ngx_log_t *log){ ngx_fd_t fd; ngx_file_info_t fi;
if (of->fd != NGX_INVALID_FILE) {
if (ngx_file_info_wrapper(name, of, &fi, log) == NGX_FILE_ERROR) { of->fd = NGX_INVALID_FILE; return NGX_ERROR; }
if (of->uniq == ngx_file_uniq(&fi)) { goto done; }
} else if (of->test_dir) {
if (ngx_file_info_wrapper(name, of, &fi, log) == NGX_FILE_ERROR) { of->fd = NGX_INVALID_FILE; return NGX_ERROR; }
if (ngx_is_dir(&fi)) { goto done; } }
if (!of->log) {
/* * Use non-blocking open() not to hang on FIFO files, etc. * This flag has no effect on a regular files. */ // 使用非阻塞io打开文件 fd = ngx_open_file_wrapper(name, of, NGX_FILE_RDONLY|NGX_FILE_NONBLOCK, NGX_FILE_OPEN, 0, log);
} else { fd = ngx_open_file_wrapper(name, of, NGX_FILE_APPEND, NGX_FILE_CREATE_OR_OPEN, NGX_FILE_DEFAULT_ACCESS, log); }
if (fd == NGX_INVALID_FILE) { of->fd = NGX_INVALID_FILE; return NGX_ERROR; } // 检测文件有效性 if (ngx_fd_info(fd, &fi) == NGX_FILE_ERROR) { ngx_log_error(NGX_LOG_CRIT, log, ngx_errno, ngx_fd_info_n " \"%V\" failed", name);
if (ngx_close_file(fd) == NGX_FILE_ERROR) { ngx_log_error(NGX_LOG_ALERT, log, ngx_errno, ngx_close_file_n " \"%V\" failed", name); }
of->fd = NGX_INVALID_FILE;
return NGX_ERROR; }
if (ngx_is_dir(&fi)) { if (ngx_close_file(fd) == NGX_FILE_ERROR) { ngx_log_error(NGX_LOG_ALERT, log, ngx_errno, ngx_close_file_n " \"%V\" failed", name); }
of->fd = NGX_INVALID_FILE;
} else { of->fd = fd; // 如果文件过大,则先预读取部分数据 if (of->read_ahead && ngx_file_size(&fi) > NGX_MIN_READ_AHEAD) { if (ngx_read_ahead(fd, of->read_ahead) == NGX_ERROR) { ngx_log_error(NGX_LOG_ALERT, log, ngx_errno, ngx_read_ahead_n " \"%V\" failed", name); } }
if (of->directio <= ngx_file_size(&fi)) { if (ngx_directio_on(fd) == NGX_FILE_ERROR) { ngx_log_error(NGX_LOG_ALERT, log, ngx_errno, ngx_directio_on_n " \"%V\" failed", name);
} else { of->is_directio = 1; } } }
done: // 复制文件信息返回 of->uniq = ngx_file_uniq(&fi); of->mtime = ngx_file_mtime(&fi); of->size = ngx_file_size(&fi); of->fs_size = ngx_file_fs_size(&fi); of->is_dir = ngx_is_dir(&fi); of->is_file = ngx_is_file(&fi); of->is_link = ngx_is_link(&fi); of->is_exec = ngx_is_exec(&fi);
return NGX_OK;}


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