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view src/event/ngx_event_busy_lock.h @ 4576:876e6b0814a5

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Fixed signed integer overflows in timer code (ticket #145). Integer overflow is undefined behaviour in C and this indeed caused problems on Solaris/SPARC (at least in some cases). Fix is to subtract unsigned integers instead, and then cast result to a signed one, which is implementation-defined behaviour and used to work. Strictly speaking, we should compare (unsigned) result with the maximum value of the corresponding signed integer type instead, this will be defined behaviour. This will require much more changes though, and considered to be overkill for now.
author Maxim Dounin <mdounin@mdounin.ru>
date Fri, 06 Apr 2012 23:46:09 +0000
parents d620f497c50f
children 457ec43dd8d5
line wrap: on
line source


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


#ifndef _NGX_EVENT_BUSY_LOCK_H_INCLUDED_
#define _NGX_EVENT_BUSY_LOCK_H_INCLUDED_


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

typedef struct ngx_event_busy_lock_ctx_s  ngx_event_busy_lock_ctx_t;

struct ngx_event_busy_lock_ctx_s {
    ngx_event_t                *event;
    ngx_event_handler_pt        handler;
    void                       *data;
    ngx_msec_t                  timer;

    unsigned                    locked:1;
    unsigned                    waiting:1;
    unsigned                    cache_updated:1;

    char                       *md5;
    ngx_int_t                   slot;

    ngx_event_busy_lock_ctx_t  *next;
};


typedef struct {
    u_char                     *md5_mask;
    char                       *md5;
    ngx_uint_t                  cacheable;

    ngx_uint_t                  busy;
    ngx_uint_t                  max_busy;

    ngx_uint_t                  waiting;
    ngx_uint_t                  max_waiting;

    ngx_event_busy_lock_ctx_t  *events;
    ngx_event_busy_lock_ctx_t  *last;

#if (NGX_THREADS)
    ngx_mutex_t                *mutex;
#endif
} ngx_event_busy_lock_t;


ngx_int_t ngx_event_busy_lock(ngx_event_busy_lock_t *bl,
    ngx_event_busy_lock_ctx_t *ctx);
ngx_int_t ngx_event_busy_lock_cacheable(ngx_event_busy_lock_t *bl,
    ngx_event_busy_lock_ctx_t *ctx);
void ngx_event_busy_unlock(ngx_event_busy_lock_t *bl,
    ngx_event_busy_lock_ctx_t *ctx);
void ngx_event_busy_lock_cancel(ngx_event_busy_lock_t *bl,
    ngx_event_busy_lock_ctx_t *ctx);


#endif /* _NGX_EVENT_BUSY_LOCK_H_INCLUDED_ */