view src/http/ngx_http_cache.h @ 8018:5119c8150478

Fixed runtime handling of systems without EPOLLRDHUP support. In 7583:efd71d49bde0 (nginx 1.17.5) along with introduction of the ioctl(FIONREAD) support proper handling of systems without EPOLLRDHUP support in the kernel (but with EPOLLRDHUP in headers) was broken. Before the change, rev->available was never set to 0 unless ngx_use_epoll_rdhup was also set (that is, runtime test for EPOLLRDHUP introduced in 6536:f7849bfb6d21 succeeded). After the change, rev->available might reach 0 on systems without runtime EPOLLRDHUP support, stopping further reading in ngx_readv_chain() and ngx_unix_recv(). And, if EOF happened to be already reported along with the last event, it is not reported again by epoll_wait(), leading to connection hangs and timeouts on such systems. This affects Linux kernels before 2.6.17 if nginx was compiled with newer headers, and, more importantly, emulation layers, such as DigitalOcean's App Platform's / gVisor's epoll emulation layer. Fix is to explicitly check ngx_use_epoll_rdhup before the corresponding rev->pending_eof tests in ngx_readv_chain() and ngx_unix_recv().
author Marcus Ball <marcus.ball@live.com>
date Mon, 30 May 2022 02:38:07 +0300
parents 3781de64e747
children
line wrap: on
line source


/*
 * Copyright (C) Igor Sysoev
 * Copyright (C) Nginx, Inc.
 */


#ifndef _NGX_HTTP_CACHE_H_INCLUDED_
#define _NGX_HTTP_CACHE_H_INCLUDED_


#include <ngx_config.h>
#include <ngx_core.h>
#include <ngx_http.h>


#define NGX_HTTP_CACHE_MISS          1
#define NGX_HTTP_CACHE_BYPASS        2
#define NGX_HTTP_CACHE_EXPIRED       3
#define NGX_HTTP_CACHE_STALE         4
#define NGX_HTTP_CACHE_UPDATING      5
#define NGX_HTTP_CACHE_REVALIDATED   6
#define NGX_HTTP_CACHE_HIT           7
#define NGX_HTTP_CACHE_SCARCE        8

#define NGX_HTTP_CACHE_KEY_LEN       16
#define NGX_HTTP_CACHE_ETAG_LEN      128
#define NGX_HTTP_CACHE_VARY_LEN      128

#define NGX_HTTP_CACHE_VERSION       5


typedef struct {
    ngx_uint_t                       status;
    time_t                           valid;
} ngx_http_cache_valid_t;


typedef struct {
    ngx_rbtree_node_t                node;
    ngx_queue_t                      queue;

    u_char                           key[NGX_HTTP_CACHE_KEY_LEN
                                         - sizeof(ngx_rbtree_key_t)];

    unsigned                         count:20;
    unsigned                         uses:10;
    unsigned                         valid_msec:10;
    unsigned                         error:10;
    unsigned                         exists:1;
    unsigned                         updating:1;
    unsigned                         deleting:1;
    unsigned                         purged:1;
                                     /* 10 unused bits */

    ngx_file_uniq_t                  uniq;
    time_t                           expire;
    time_t                           valid_sec;
    size_t                           body_start;
    off_t                            fs_size;
    ngx_msec_t                       lock_time;
} ngx_http_file_cache_node_t;


struct ngx_http_cache_s {
    ngx_file_t                       file;
    ngx_array_t                      keys;
    uint32_t                         crc32;
    u_char                           key[NGX_HTTP_CACHE_KEY_LEN];
    u_char                           main[NGX_HTTP_CACHE_KEY_LEN];

    ngx_file_uniq_t                  uniq;
    time_t                           valid_sec;
    time_t                           updating_sec;
    time_t                           error_sec;
    time_t                           last_modified;
    time_t                           date;

    ngx_str_t                        etag;
    ngx_str_t                        vary;
    u_char                           variant[NGX_HTTP_CACHE_KEY_LEN];

    size_t                           buffer_size;
    size_t                           header_start;
    size_t                           body_start;
    off_t                            length;
    off_t                            fs_size;

    ngx_uint_t                       min_uses;
    ngx_uint_t                       error;
    ngx_uint_t                       valid_msec;
    ngx_uint_t                       vary_tag;

    ngx_buf_t                       *buf;

    ngx_http_file_cache_t           *file_cache;
    ngx_http_file_cache_node_t      *node;

#if (NGX_THREADS || NGX_COMPAT)
    ngx_thread_task_t               *thread_task;
#endif

    ngx_msec_t                       lock_timeout;
    ngx_msec_t                       lock_age;
    ngx_msec_t                       lock_time;
    ngx_msec_t                       wait_time;

    ngx_event_t                      wait_event;

    unsigned                         lock:1;
    unsigned                         waiting:1;

    unsigned                         updated:1;
    unsigned                         updating:1;
    unsigned                         exists:1;
    unsigned                         temp_file:1;
    unsigned                         purged:1;
    unsigned                         reading:1;
    unsigned                         secondary:1;
    unsigned                         update_variant:1;
    unsigned                         background:1;

    unsigned                         stale_updating:1;
    unsigned                         stale_error:1;
};


typedef struct {
    ngx_uint_t                       version;
    time_t                           valid_sec;
    time_t                           updating_sec;
    time_t                           error_sec;
    time_t                           last_modified;
    time_t                           date;
    uint32_t                         crc32;
    u_short                          valid_msec;
    u_short                          header_start;
    u_short                          body_start;
    u_char                           etag_len;
    u_char                           etag[NGX_HTTP_CACHE_ETAG_LEN];
    u_char                           vary_len;
    u_char                           vary[NGX_HTTP_CACHE_VARY_LEN];
    u_char                           variant[NGX_HTTP_CACHE_KEY_LEN];
} ngx_http_file_cache_header_t;


typedef struct {
    ngx_rbtree_t                     rbtree;
    ngx_rbtree_node_t                sentinel;
    ngx_queue_t                      queue;
    ngx_atomic_t                     cold;
    ngx_atomic_t                     loading;
    off_t                            size;
    ngx_uint_t                       count;
    ngx_uint_t                       watermark;
} ngx_http_file_cache_sh_t;


struct ngx_http_file_cache_s {
    ngx_http_file_cache_sh_t        *sh;
    ngx_slab_pool_t                 *shpool;

    ngx_path_t                      *path;

    off_t                            min_free;
    off_t                            max_size;
    size_t                           bsize;

    time_t                           inactive;

    time_t                           fail_time;

    ngx_uint_t                       files;
    ngx_uint_t                       loader_files;
    ngx_msec_t                       last;
    ngx_msec_t                       loader_sleep;
    ngx_msec_t                       loader_threshold;

    ngx_uint_t                       manager_files;
    ngx_msec_t                       manager_sleep;
    ngx_msec_t                       manager_threshold;

    ngx_shm_zone_t                  *shm_zone;

    ngx_uint_t                       use_temp_path;
                                     /* unsigned use_temp_path:1 */
};


ngx_int_t ngx_http_file_cache_new(ngx_http_request_t *r);
ngx_int_t ngx_http_file_cache_create(ngx_http_request_t *r);
void ngx_http_file_cache_create_key(ngx_http_request_t *r);
ngx_int_t ngx_http_file_cache_open(ngx_http_request_t *r);
ngx_int_t ngx_http_file_cache_set_header(ngx_http_request_t *r, u_char *buf);
void ngx_http_file_cache_update(ngx_http_request_t *r, ngx_temp_file_t *tf);
void ngx_http_file_cache_update_header(ngx_http_request_t *r);
ngx_int_t ngx_http_cache_send(ngx_http_request_t *);
void ngx_http_file_cache_free(ngx_http_cache_t *c, ngx_temp_file_t *tf);
time_t ngx_http_file_cache_valid(ngx_array_t *cache_valid, ngx_uint_t status);

char *ngx_http_file_cache_set_slot(ngx_conf_t *cf, ngx_command_t *cmd,
    void *conf);
char *ngx_http_file_cache_valid_set_slot(ngx_conf_t *cf, ngx_command_t *cmd,
    void *conf);


extern ngx_str_t  ngx_http_cache_status[];


#endif /* _NGX_HTTP_CACHE_H_INCLUDED_ */