Mercurial > hg > nginx
view src/core/ngx_buf.h @ 5992:174512857ccf
Cache: do not inherit last_modified and etag from stale response.
When replacing a stale cache entry, its last_modified and etag could be
inherited from the old entry if the response code is not 200 or 206. Moreover,
etag could be inherited with any response code if it's missing in the new
response. As a result, the cache entry is left with invalid last_modified or
etag which could lead to broken revalidation.
For example, when a file is deleted from backend, its last_modified is copied to
the new 404 cache entry and is used later for revalidation. Once the old file
appears again with its original timestamp, revalidation succeeds and the cached
404 response is sent to client instead of the file.
The problem appeared with etags in 44b9ab7752e3 (1.7.3) and affected
last_modified in 1573fc7875fa (1.7.9).
author | Roman Arutyunyan <arut@nginx.com> |
---|---|
date | Mon, 02 Mar 2015 19:47:13 +0300 |
parents | 0f234ee664f7 |
children | 1fdba317ee6d |
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/* * Copyright (C) Igor Sysoev * Copyright (C) Nginx, Inc. */ #ifndef _NGX_BUF_H_INCLUDED_ #define _NGX_BUF_H_INCLUDED_ #include <ngx_config.h> #include <ngx_core.h> typedef void * ngx_buf_tag_t; typedef struct ngx_buf_s ngx_buf_t; struct ngx_buf_s { u_char *pos; u_char *last; off_t file_pos; off_t file_last; u_char *start; /* start of buffer */ u_char *end; /* end of buffer */ ngx_buf_tag_t tag; ngx_file_t *file; ngx_buf_t *shadow; /* the buf's content could be changed */ unsigned temporary:1; /* * the buf's content is in a memory cache or in a read only memory * and must not be changed */ unsigned memory:1; /* the buf's content is mmap()ed and must not be changed */ unsigned mmap:1; unsigned recycled:1; unsigned in_file:1; unsigned flush:1; unsigned sync:1; unsigned last_buf:1; unsigned last_in_chain:1; unsigned last_shadow:1; unsigned temp_file:1; /* STUB */ int num; }; struct ngx_chain_s { ngx_buf_t *buf; ngx_chain_t *next; }; typedef struct { ngx_int_t num; size_t size; } ngx_bufs_t; typedef struct ngx_output_chain_ctx_s ngx_output_chain_ctx_t; typedef ngx_int_t (*ngx_output_chain_filter_pt)(void *ctx, ngx_chain_t *in); #if (NGX_HAVE_FILE_AIO) typedef void (*ngx_output_chain_aio_pt)(ngx_output_chain_ctx_t *ctx, ngx_file_t *file); #endif struct ngx_output_chain_ctx_s { ngx_buf_t *buf; ngx_chain_t *in; ngx_chain_t *free; ngx_chain_t *busy; unsigned sendfile:1; unsigned directio:1; #if (NGX_HAVE_ALIGNED_DIRECTIO) unsigned unaligned:1; #endif unsigned need_in_memory:1; unsigned need_in_temp:1; #if (NGX_HAVE_FILE_AIO) unsigned aio:1; ngx_output_chain_aio_pt aio_handler; #if (NGX_HAVE_AIO_SENDFILE) ssize_t (*aio_preload)(ngx_buf_t *file); #endif #endif off_t alignment; ngx_pool_t *pool; ngx_int_t allocated; ngx_bufs_t bufs; ngx_buf_tag_t tag; ngx_output_chain_filter_pt output_filter; void *filter_ctx; }; typedef struct { ngx_chain_t *out; ngx_chain_t **last; ngx_connection_t *connection; ngx_pool_t *pool; off_t limit; } ngx_chain_writer_ctx_t; #define NGX_CHAIN_ERROR (ngx_chain_t *) NGX_ERROR #define ngx_buf_in_memory(b) (b->temporary || b->memory || b->mmap) #define ngx_buf_in_memory_only(b) (ngx_buf_in_memory(b) && !b->in_file) #define ngx_buf_special(b) \ ((b->flush || b->last_buf || b->sync) \ && !ngx_buf_in_memory(b) && !b->in_file) #define ngx_buf_sync_only(b) \ (b->sync \ && !ngx_buf_in_memory(b) && !b->in_file && !b->flush && !b->last_buf) #define ngx_buf_size(b) \ (ngx_buf_in_memory(b) ? (off_t) (b->last - b->pos): \ (b->file_last - b->file_pos)) ngx_buf_t *ngx_create_temp_buf(ngx_pool_t *pool, size_t size); ngx_chain_t *ngx_create_chain_of_bufs(ngx_pool_t *pool, ngx_bufs_t *bufs); #define ngx_alloc_buf(pool) ngx_palloc(pool, sizeof(ngx_buf_t)) #define ngx_calloc_buf(pool) ngx_pcalloc(pool, sizeof(ngx_buf_t)) ngx_chain_t *ngx_alloc_chain_link(ngx_pool_t *pool); #define ngx_free_chain(pool, cl) \ cl->next = pool->chain; \ pool->chain = cl ngx_int_t ngx_output_chain(ngx_output_chain_ctx_t *ctx, ngx_chain_t *in); ngx_int_t ngx_chain_writer(void *ctx, ngx_chain_t *in); ngx_int_t ngx_chain_add_copy(ngx_pool_t *pool, ngx_chain_t **chain, ngx_chain_t *in); ngx_chain_t *ngx_chain_get_free_buf(ngx_pool_t *p, ngx_chain_t **free); void ngx_chain_update_chains(ngx_pool_t *p, ngx_chain_t **free, ngx_chain_t **busy, ngx_chain_t **out, ngx_buf_tag_t tag); off_t ngx_chain_coalesce_file(ngx_chain_t **in, off_t limit); ngx_chain_t *ngx_chain_update_sent(ngx_chain_t *in, off_t sent); #endif /* _NGX_BUF_H_INCLUDED_ */