Mercurial > hg > nginx-quic
view src/event/ngx_event_busy_lock.h @ 3293:8abb88374c6c
Fix a bug introduced in r2032: After a child process has read a terminate
message from a channel, the process tries to read the channel again.
The kernel (at least FreeBSD) may preempt the process and sends a SIGIO
signal to a master process. The master process sends a new terminate message,
the kernel switches again to the the child process, and the child process
reads the messages instead of an EAGAIN error. And this may repeat over
and over. Being that the child process can not exit the cycle and test
the termination flag set by the message handler.
The fix disallow the master process to send a new terminate message on
SIGIO signal reception. It may send the message only on SIGALARM signal.
author | Igor Sysoev <igor@sysoev.ru> |
---|---|
date | Wed, 04 Nov 2009 19:41:08 +0000 |
parents | 4c43e25d11ea |
children | d620f497c50f |
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/* * Copyright (C) Igor Sysoev */ #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_ */