view src/core/ngx_shmtx.h @ 6957:83bae3d354ab

HTTP/2: fixed connection finalization. All streams in connection must be finalized before the connection itself can be finalized and all related memory is freed. That's not always possible on the current event loop iteration. Thus when the last stream is finalized, it sets the special read event handler ngx_http_v2_handle_connection_handler() and posts the event. Previously, this handler didn't check the connection state and could call the regular event handler on a connection that was already in finalization stage. In the worst case that could lead to a segmentation fault, since some data structures aren't supposed to be used during connection finalization. Particularly, the waiting queue can contain already freed streams, so the WINDOW_UPDATE frame received by that moment could trigger accessing to these freed streams. Now, the connection error flag is explicitly checked in ngx_http_v2_handle_connection_handler().
author Valentin Bartenev <vbart@nginx.com>
date Wed, 29 Mar 2017 20:21:01 +0300
parents 512c741fa841
children
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/*
 * Copyright (C) Igor Sysoev
 * Copyright (C) Nginx, Inc.
 */


#ifndef _NGX_SHMTX_H_INCLUDED_
#define _NGX_SHMTX_H_INCLUDED_


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


typedef struct {
    ngx_atomic_t   lock;
#if (NGX_HAVE_POSIX_SEM)
    ngx_atomic_t   wait;
#endif
} ngx_shmtx_sh_t;


typedef struct {
#if (NGX_HAVE_ATOMIC_OPS)
    ngx_atomic_t  *lock;
#if (NGX_HAVE_POSIX_SEM)
    ngx_atomic_t  *wait;
    ngx_uint_t     semaphore;
    sem_t          sem;
#endif
#else
    ngx_fd_t       fd;
    u_char        *name;
#endif
    ngx_uint_t     spin;
} ngx_shmtx_t;


ngx_int_t ngx_shmtx_create(ngx_shmtx_t *mtx, ngx_shmtx_sh_t *addr,
    u_char *name);
void ngx_shmtx_destroy(ngx_shmtx_t *mtx);
ngx_uint_t ngx_shmtx_trylock(ngx_shmtx_t *mtx);
void ngx_shmtx_lock(ngx_shmtx_t *mtx);
void ngx_shmtx_unlock(ngx_shmtx_t *mtx);
ngx_uint_t ngx_shmtx_force_unlock(ngx_shmtx_t *mtx, ngx_pid_t pid);


#endif /* _NGX_SHMTX_H_INCLUDED_ */