Mercurial > hg > nginx
view src/event/ngx_event_mutex.c @ 4576:876e6b0814a5
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 | 3377f9459e99 |
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/* * Copyright (C) Igor Sysoev * Copyright (C) Nginx, Inc. */ #include <ngx_config.h> #include <ngx_core.h> #include <ngx_event.h> ngx_int_t ngx_event_mutex_timedlock(ngx_event_mutex_t *m, ngx_msec_t timer, ngx_event_t *ev) { ngx_log_debug2(NGX_LOG_DEBUG_EVENT, ev->log, 0, "lock event mutex %p lock:%XD", m, m->lock); if (m->lock) { if (m->events == NULL) { m->events = ev; } else { m->last->next = ev; } m->last = ev; ev->next = NULL; #if (NGX_THREADS0) ev->light = 1; #endif ngx_add_timer(ev, timer); return NGX_AGAIN; } m->lock = 1; return NGX_OK; } ngx_int_t ngx_event_mutex_unlock(ngx_event_mutex_t *m, ngx_log_t *log) { ngx_event_t *ev; if (m->lock == 0) { ngx_log_error(NGX_LOG_ALERT, log, 0, "tring to unlock the free event mutex %p", m); return NGX_ERROR; } ngx_log_debug2(NGX_LOG_DEBUG_EVENT, log, 0, "unlock event mutex %p, next event: %p", m, m->events); m->lock = 0; if (m->events) { ev = m->events; m->events = ev->next; ev->next = (ngx_event_t *) ngx_posted_events; ngx_posted_events = ev; } return NGX_OK; }