Merge of r5004, r5019-r5025: ssl fixes. *) SSL: speedup loading of configs with many ssl servers. The patch saves one EC_KEY_generate_key() call per server{} block by informing OpenSSL about SSL_OP_SINGLE_ECDH_USE we are going to use before the SSL_CTX_set_tmp_ecdh() call. For a configuration file with 10k simple server{} blocks with SSL enabled this change reduces startup time from 18s to 5s on a slow test box here. *) SSL: removed conditions that always hold true. *) SSL: resetting of flush flag after the data was written. There is no need to flush next chunk of data if it does not contain a buffer with the flush or last_buf flags set. *) SSL: preservation of flush flag for buffered data. Previously, if SSL buffer was not sent we lost information that the data must be flushed. *) SSL: calculation of buffer size moved closer to its usage. No functional changes. *) SSL: avoid calling SSL_write() with zero data size. According to documentation, calling SSL_write() with num=0 bytes to be sent results in undefined behavior. We don't currently call ngx_ssl_send_chain() with empty chain and buffer. This check handles the case of a chain with total data size that is a multiple of NGX_SSL_BUFSIZE, and with the special buffer at the end. In practice such cases resulted in premature connection close and critical error "SSL_write() failed (SSL:)" in the error log. *) SSL: take into account data in the buffer while limiting output. In some rare cases this can result in a more smooth sending rate. *) SSL: fixed ngx_ssl_handshake() with level-triggered event methods. Missing calls to ngx_handle_write_event() and ngx_handle_read_event() resulted in a CPU hog during SSL handshake if an level-triggered event method (e.g. select) was used.

/*
 * 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_ */