ngx_kqueue_module.c

Nginx ("engine x") 是一个高性能的 HTTP 和 反向代理 服务器

/*
 * Copyright (C) Igor Sysoev
 */


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


typedef struct {
    ngx_uint_t  changes;
    ngx_uint_t  events;
} ngx_kqueue_conf_t;


static ngx_int_t ngx_kqueue_init(ngx_cycle_t *cycle, ngx_msec_t timer);
static void ngx_kqueue_done(ngx_cycle_t *cycle);
static ngx_int_t ngx_kqueue_add_event(ngx_event_t *ev, ngx_int_t event,
    ngx_uint_t flags);
static ngx_int_t ngx_kqueue_del_event(ngx_event_t *ev, ngx_int_t event,
    ngx_uint_t flags);
static ngx_int_t ngx_kqueue_set_event(ngx_event_t *ev, ngx_int_t filter,
    ngx_uint_t flags);
static ngx_int_t ngx_kqueue_process_changes(ngx_cycle_t *cycle, ngx_uint_t try);
static ngx_int_t ngx_kqueue_process_events(ngx_cycle_t *cycle, ngx_msec_t timer,
    ngx_uint_t flags);
static ngx_inline void ngx_kqueue_dump_event(ngx_log_t *log,
    struct kevent *kev);

static void *ngx_kqueue_create_conf(ngx_cycle_t *cycle);
static char *ngx_kqueue_init_conf(ngx_cycle_t *cycle, void *conf);


int                    ngx_kqueue = -1;

/*
 * The "change_list" should be declared as ngx_thread_volatile.
 * However, the use of the change_list is localized in kqueue functions and
 * is protected by the mutex so even the "icc -ipo" should not build the code
 * with the race condition.  Thus we avoid the declaration to make a more
 * readable code.
 */

static struct kevent  *change_list, *change_list0, *change_list1;
static struct kevent  *event_list;
static ngx_uint_t      max_changes, nchanges, nevents;

#if (NGX_THREADS)
static ngx_mutex_t    *list_mutex;
static ngx_mutex_t    *kevent_mutex;
#endif



static ngx_str_t      kqueue_name = ngx_string("kqueue");

static ngx_command_t  ngx_kqueue_commands[] = {

    { ngx_string("kqueue_changes"),
      NGX_EVENT_CONF|NGX_CONF_TAKE1,
      ngx_conf_set_num_slot,
      0,
      offsetof(ngx_kqueue_conf_t, changes),
      NULL },

    { ngx_string("kqueue_events"),
      NGX_EVENT_CONF|NGX_CONF_TAKE1,
      ngx_conf_set_num_slot,
      0,
      offsetof(ngx_kqueue_conf_t, events),
      NULL },

      ngx_null_command
};


ngx_event_module_t  ngx_kqueue_module_ctx = {
    &kqueue_name,
    ngx_kqueue_create_conf,                /* create configuration */
    ngx_kqueue_init_conf,                  /* init configuration */

    {
        ngx_kqueue_add_event,              /* add an event */
        ngx_kqueue_del_event,              /* delete an event */
        ngx_kqueue_add_event,              /* enable an event */
        ngx_kqueue_del_event,              /* disable an event */
        NULL,                              /* add an connection */
        NULL,                              /* delete an connection */
        ngx_kqueue_process_changes,        /* process the changes */
        ngx_kqueue_process_events,         /* process the events */
        ngx_kqueue_init,                   /* init the events */
        ngx_kqueue_done                    /* done the events */
    }

};

ngx_module_t  ngx_kqueue_module = {
    NGX_MODULE_V1,
    &ngx_kqueue_module_ctx,                /* module context */
    ngx_kqueue_commands,                   /* module directives */
    NGX_EVENT_MODULE,                      /* module type */
    NULL,                                  /* init master */
    NULL,                                  /* init module */
    NULL,                                  /* init process */
    NULL,                                  /* init thread */
    NULL,                                  /* exit thread */
    NULL,                                  /* exit process */
    NULL,                                  /* exit master */
    NGX_MODULE_V1_PADDING
};



static ngx_int_t
ngx_kqueue_init(ngx_cycle_t *cycle, ngx_msec_t timer)
{
    ngx_kqueue_conf_t  *kcf;
    struct timespec     ts;
#if (NGX_HAVE_TIMER_EVENT)
    struct kevent       kev;
#endif

    kcf = ngx_event_get_conf(cycle->conf_ctx, ngx_kqueue_module);

    if (ngx_kqueue == -1) {
        ngx_kqueue = kqueue();

        if (ngx_kqueue == -1) {
            ngx_log_error(NGX_LOG_EMERG, cycle->log, ngx_errno,
                          "kqueue() failed");
            return NGX_ERROR;
        }

#if (NGX_THREADS)

        list_mutex = ngx_mutex_init(cycle->log, 0);
        if (list_mutex == NULL) {
            return NGX_ERROR;
        }

        kevent_mutex = ngx_mutex_init(cycle->log, 0);
        if (kevent_mutex == NULL) {
            return NGX_ERROR;
        }

#endif
    }

    if (max_changes < kcf->changes) {
        if (nchanges) {
            ts.tv_sec = 0;
            ts.tv_nsec = 0;

            if (kevent(ngx_kqueue, change_list, (int) nchanges, NULL, 0, &ts)
                == -1)
            {
                ngx_log_error(NGX_LOG_ALERT, cycle->log, ngx_errno,
                              "kevent() failed");
                return NGX_ERROR;
            }
            nchanges = 0;
        }

        if (change_list0) {
            ngx_free(change_list0);
        }

        change_list0 = ngx_alloc(kcf->changes * sizeof(struct kevent),
                                 cycle->log);
        if (change_list0 == NULL) {
            return NGX_ERROR;
        }

        if (change_list1) {
            ngx_free(change_list1);
        }

        change_list1 = ngx_alloc(kcf->changes * sizeof(struct kevent),
                                 cycle->log);
        if (change_list1 == NULL) {
            return NGX_ERROR;
        }

        change_list = change_list0;
    }

    max_changes = kcf->changes;

    if (nevents < kcf->events) {
        if (event_list) {
            ngx_free(event_list);
        }

        event_list = ngx_alloc(kcf->events * sizeof(struct kevent), cycle->log);
        if (event_list == NULL) {
            return NGX_ERROR;
        }
    }

    ngx_event_flags = 0;

#if (NGX_HAVE_TIMER_EVENT)

    if (timer) {
        kev.ident = 0;
        kev.filter = EVFILT_TIMER;
        kev.flags = EV_ADD|EV_ENABLE;
        kev.fflags = 0;
        kev.data = timer;
        kev.udata = 0;

        ts.tv_sec = 0;
        ts.tv_nsec = 0;

        if (kevent(ngx_kqueue, &kev, 1, NULL, 0, &ts) == -1) {
            ngx_log_error(NGX_LOG_ALERT, cycle->log, ngx_errno,
                          "kevent(EVFILT_TIMER) failed");
            return NGX_ERROR;
        }

        ngx_event_flags |= NGX_USE_TIMER_EVENT;
    }

#endif

    ngx_event_flags |= NGX_USE_ONESHOT_EVENT|NGX_USE_KQUEUE_EVENT;

#if (NGX_HAVE_CLEAR_EVENT)
    ngx_event_flags |= NGX_USE_CLEAR_EVENT;
#else
    ngx_event_flags |= NGX_USE_LEVEL_EVENT;
#endif

#if (NGX_HAVE_LOWAT_EVENT)
    ngx_event_flags |= NGX_USE_LOWAT_EVENT;
#endif

    nevents = kcf->events;

    ngx_io = ngx_os_io;

    ngx_event_actions = ngx_kqueue_module_ctx.actions;

    return NGX_OK;
}


static void
ngx_kqueue_done(ngx_cycle_t *cycle)
{
    if (close(ngx_kqueue) == -1) {
        ngx_log_error(NGX_LOG_ALERT, cycle->log, ngx_errno,
                      "kqueue close() failed");
    }

    ngx_kqueue = -1;

#if (NGX_THREADS)
    ngx_mutex_destroy(kevent_mutex);
    ngx_mutex_destroy(list_mutex);
#endif

    ngx_free(change_list1);
    ngx_free(change_list0);
    ngx_free(event_list);

    change_list1 = NULL;
    change_list0 = NULL;
    change_list = NULL;
    event_list = NULL;
    max_changes = 0;
    nchanges = 0;
    nevents = 0;
}


static ngx_int_t
ngx_kqueue_add_event(ngx_event_t *ev, ngx_int_t event, ngx_uint_t flags)
{
    ngx_int_t          rc;
#if 0
    ngx_event_t       *e;
    ngx_connection_t  *c;
#endif

    ev->active = 1;
    ev->disabled = 0;
    ev->oneshot = (flags & NGX_ONESHOT_EVENT) ? 1 : 0;

    ngx_mutex_lock(list_mutex);

#if 0

    if (ev->index < nchanges
        && ((uintptr_t) change_list[ev->index].udata & (uintptr_t) ~1)
            == (uintptr_t) ev)
    {
        if (change_list[ev->index].flags == EV_DISABLE) {

            /*
             * if the EV_DISABLE is still not passed to a kernel
             * we will not pass it
             */

            ngx_log_debug2(NGX_LOG_DEBUG_EVENT, ev->log, 0,
                           "kevent activated: %d: ft:%i",
                           ngx_event_ident(ev->data), event);

            if (ev->index < --nchanges) {
                e = (ngx_event_t *)
                    ((uintptr_t) change_list[nchanges].udata & (uintptr_t) ~1);
                change_list[ev->index] = change_list[nchanges];
                e->index = ev->index;
            }

            ngx_mutex_unlock(list_mutex);

            return NGX_OK;
        }

        c = ev->data;

        ngx_log_error(NGX_LOG_ALERT, ev->log, 0,
                      "previous event on #%d were not passed in kernel", c->fd);

        ngx_mutex_unlock(list_mutex);

        return NGX_ERROR;
    }

#endif

    rc = ngx_kqueue_set_event(ev, event, EV_ADD|EV_ENABLE|flags);

    ngx_mutex_unlock(list_mutex);

    return rc;
}


static ngx_int_t
ngx_kqueue_del_event(ngx_event_t *ev, ngx_int_t event, ngx_uint_t flags)
{
    ngx_int_t     rc;
    ngx_event_t  *e;

    ev->active = 0;
    ev->disabled = 0;

    ngx_mutex_lock(list_mutex);

    if (ev->index < nchanges
        && ((uintptr_t) change_list[ev->index].udata & (uintptr_t) ~1)
            == (uintptr_t) ev)
    {
        ngx_log_debug2(NGX_LOG_DEBUG_EVENT, ev->log, 0,
                       "kevent deleted: %d: ft:%i",
                       ngx_event_ident(ev->data), event);

        /* if the event is still not passed to a kernel we will not pass it */

        nchanges--;

        if (ev->index < nchanges) {
            e = (ngx_event_t *)
                    ((uintptr_t) change_list[nchanges].udata & (uintptr_t) ~1);
            change_list[ev->index] = change_list[nchanges];
            e->index = ev->index;
        }

        ngx_mutex_unlock(list_mutex);

        return NGX_OK;
    }

    /*
     * when the file descriptor is closed the kqueue automatically deletes
     * its filters so we do not need to delete explicity the event
     * before the closing the file descriptor.
     */

    if (flags & NGX_CLOSE_EVENT) {
        ngx_mutex_unlock(list_mutex);
        return NGX_OK;