view src/core/ngx_cycle.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 f18db38a9826
children
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/*
 * Copyright (C) Igor Sysoev
 * Copyright (C) Nginx, Inc.
 */


#ifndef _NGX_CYCLE_H_INCLUDED_
#define _NGX_CYCLE_H_INCLUDED_


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


#ifndef NGX_CYCLE_POOL_SIZE
#define NGX_CYCLE_POOL_SIZE     NGX_DEFAULT_POOL_SIZE
#endif


#define NGX_DEBUG_POINTS_STOP   1
#define NGX_DEBUG_POINTS_ABORT  2


typedef struct ngx_shm_zone_s  ngx_shm_zone_t;

typedef ngx_int_t (*ngx_shm_zone_init_pt) (ngx_shm_zone_t *zone, void *data);

struct ngx_shm_zone_s {
    void                     *data;
    ngx_shm_t                 shm;
    ngx_shm_zone_init_pt      init;
    void                     *tag;
    void                     *sync;
    ngx_uint_t                noreuse;  /* unsigned  noreuse:1; */
};


struct ngx_cycle_s {
    void                  ****conf_ctx;
    ngx_pool_t               *pool;

    ngx_log_t                *log;
    ngx_log_t                 new_log;

    ngx_uint_t                log_use_stderr;  /* unsigned  log_use_stderr:1; */

    ngx_connection_t        **files;
    ngx_connection_t         *free_connections;
    ngx_uint_t                free_connection_n;

    ngx_module_t            **modules;
    ngx_uint_t                modules_n;
    ngx_uint_t                modules_used;    /* unsigned  modules_used:1; */

    ngx_queue_t               reusable_connections_queue;
    ngx_uint_t                reusable_connections_n;
    time_t                    connections_reuse_time;

    ngx_array_t               listening;
    ngx_array_t               paths;

    ngx_array_t               config_dump;
    ngx_rbtree_t              config_dump_rbtree;
    ngx_rbtree_node_t         config_dump_sentinel;

    ngx_list_t                open_files;
    ngx_list_t                shared_memory;

    ngx_uint_t                connection_n;
    ngx_uint_t                files_n;

    ngx_connection_t         *connections;
    ngx_event_t              *read_events;
    ngx_event_t              *write_events;

    ngx_cycle_t              *old_cycle;

    ngx_str_t                 conf_file;
    ngx_str_t                 conf_param;
    ngx_str_t                 conf_prefix;
    ngx_str_t                 prefix;
    ngx_str_t                 error_log;
    ngx_str_t                 lock_file;
    ngx_str_t                 hostname;
};


typedef struct {
    ngx_flag_t                daemon;
    ngx_flag_t                master;

    ngx_msec_t                timer_resolution;
    ngx_msec_t                shutdown_timeout;

    ngx_int_t                 worker_processes;
    ngx_int_t                 debug_points;

    ngx_int_t                 rlimit_nofile;
    off_t                     rlimit_core;

    int                       priority;

    ngx_uint_t                cpu_affinity_auto;
    ngx_uint_t                cpu_affinity_n;
    ngx_cpuset_t             *cpu_affinity;

    char                     *username;
    ngx_uid_t                 user;
    ngx_gid_t                 group;

    ngx_str_t                 working_directory;
    ngx_str_t                 lock_file;

    ngx_str_t                 pid;
    ngx_str_t                 oldpid;

    ngx_array_t               env;
    char                    **environment;

    ngx_uint_t                transparent;  /* unsigned  transparent:1; */
} ngx_core_conf_t;


#define ngx_is_init_cycle(cycle)  (cycle->conf_ctx == NULL)


ngx_cycle_t *ngx_init_cycle(ngx_cycle_t *old_cycle);
ngx_int_t ngx_create_pidfile(ngx_str_t *name, ngx_log_t *log);
void ngx_delete_pidfile(ngx_cycle_t *cycle);
ngx_int_t ngx_signal_process(ngx_cycle_t *cycle, char *sig);
void ngx_reopen_files(ngx_cycle_t *cycle, ngx_uid_t user);
char **ngx_set_environment(ngx_cycle_t *cycle, ngx_uint_t *last);
ngx_pid_t ngx_exec_new_binary(ngx_cycle_t *cycle, char *const *argv);
ngx_cpuset_t *ngx_get_cpu_affinity(ngx_uint_t n);
ngx_shm_zone_t *ngx_shared_memory_add(ngx_conf_t *cf, ngx_str_t *name,
    size_t size, void *tag);
void ngx_set_shutdown_timer(ngx_cycle_t *cycle);


extern volatile ngx_cycle_t  *ngx_cycle;
extern ngx_array_t            ngx_old_cycles;
extern ngx_module_t           ngx_core_module;
extern ngx_uint_t             ngx_test_config;
extern ngx_uint_t             ngx_dump_config;
extern ngx_uint_t             ngx_quiet_mode;


#endif /* _NGX_CYCLE_H_INCLUDED_ */