res_timing_kqueue.c

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/*
 * Asterisk -- An open source telephony toolkit.
 *
 * Copyright (C) 2010, Digium, Inc.
 *
 * Tilghman Lesher <tlesher AT digium DOT com>
 *
 * See http://www.asterisk.org for more information about
 * the Asterisk project. Please do not directly contact
 * any of the maintainers of this project for assistance;
 * the project provides a web site, mailing lists and IRC
 * channels for your use.
 *
 * This program is free software, distributed under the terms of
 * the GNU General Public License Version 2. See the LICENSE file
 * at the top of the source tree.
 */
 
/*!
 * \file
 * \author Tilghman Lesher \verbatim <tlesher AT digium DOT com> \endverbatim
 *
 * \brief kqueue timing interface
 *
 * \ingroup resource
 */
 
/*** MODULEINFO
    <depend>kqueue</depend>
    <conflict>launchd</conflict>
    <support_level>extended</support_level>
 ***/
 
#include "asterisk.h"
 
#include <sys/types.h>
#include <sys/event.h>
#include <sys/time.h>
 
#include "asterisk/module.h"
#include "asterisk/astobj2.h"
#include "asterisk/timing.h"
#include "asterisk/logger.h"
#include "asterisk/utils.h"
#include "asterisk/time.h"
#include "asterisk/test.h"
#include "asterisk/poll-compat.h"       /* for ast_poll() */
 
static void *timing_funcs_handle;
 
static void *kqueue_timer_open(void);
static void kqueue_timer_close(void *data);
static int kqueue_timer_set_rate(void *data, unsigned int rate);
static int kqueue_timer_ack(void *data, unsigned int quantity);
static int kqueue_timer_enable_continuous(void *data);
static int kqueue_timer_disable_continuous(void *data);
static enum ast_timer_event kqueue_timer_get_event(void *data);
static unsigned int kqueue_timer_get_max_rate(void *data);
static int kqueue_timer_fd(void *data);
 
static struct ast_timing_interface kqueue_timing = {
    .name = "kqueue",
    .priority = 150,
    .timer_open = kqueue_timer_open,
    .timer_close = kqueue_timer_close,
    .timer_set_rate = kqueue_timer_set_rate,
    .timer_ack = kqueue_timer_ack,
    .timer_enable_continuous = kqueue_timer_enable_continuous,
    .timer_disable_continuous = kqueue_timer_disable_continuous,
    .timer_get_event = kqueue_timer_get_event,
    .timer_get_max_rate = kqueue_timer_get_max_rate,
    .timer_fd = kqueue_timer_fd,
};
 
struct kqueue_timer {
    intptr_t period;
    int handle;
#ifndef EVFILT_USER
    int continuous_fd;
    unsigned int continuous_fd_valid:1;
#endif
    unsigned int is_continuous:1;
};
 
#ifdef EVFILT_USER
#define CONTINUOUS_EVFILT_TYPE EVFILT_USER
static int kqueue_timer_init_continuous_event(struct kqueue_timer *timer)
{
    return 0;
}
 
static int kqueue_timer_enable_continuous_event(struct kqueue_timer *timer)
{
    struct kevent kev[2];
 
    EV_SET(&kev[0], (uintptr_t)timer, EVFILT_USER, EV_ADD | EV_ENABLE,
        0, 0, NULL);
    EV_SET(&kev[1], (uintptr_t)timer, EVFILT_USER, 0, NOTE_TRIGGER,
        0, NULL);
    return kevent(timer->handle, kev, 2, NULL, 0, NULL);
}
 
static int kqueue_timer_disable_continuous_event(struct kqueue_timer *timer)
{
    struct kevent kev;
 
    EV_SET(&kev, (uintptr_t)timer, EVFILT_USER, EV_DELETE, 0, 0, NULL);
    return kevent(timer->handle, &kev, 1, NULL, 0, NULL);
}
 
static void kqueue_timer_fini_continuous_event(struct kqueue_timer *timer)
{
}
 
#else /* EVFILT_USER */
 
#define CONTINUOUS_EVFILT_TYPE EVFILT_READ
static int kqueue_timer_init_continuous_event(struct kqueue_timer *timer)
{
    int pipefds[2];
    int retval;
 
    retval = pipe(pipefds);
    if (retval == 0) {
        timer->continuous_fd = pipefds[0];
        timer->continuous_fd_valid = 1;
        close(pipefds[1]);
    }
    return retval;
}
 
static void kqueue_timer_fini_continuous_event(struct kqueue_timer *timer)
{
    if (timer->continuous_fd_valid) {
        close(timer->continuous_fd);
    }
}
 
static int kqueue_timer_enable_continuous_event(struct kqueue_timer *timer)
{
    struct kevent kev;
 
    EV_SET(&kev, timer->continuous_fd, EVFILT_READ, EV_ADD | EV_ENABLE,
        0, 0, NULL);
    return kevent(timer->handle, &kev, 1, NULL, 0, NULL);
}
 
static int kqueue_timer_disable_continuous_event(struct kqueue_timer *timer)
{
    struct kevent kev;
 
    EV_SET(&kev, timer->continuous_fd, EVFILT_READ, EV_DELETE, 0, 0, NULL);
    return kevent(timer->handle, &kev, 1, NULL, 0, NULL);
}
#endif
 
static void timer_destroy(void *obj)
{
    struct kqueue_timer *timer = obj;
    ast_debug(5, "[%d]: Timer Destroy\n", timer->handle);
    kqueue_timer_fini_continuous_event(timer);
    if (timer->handle > -1) {
        close(timer->handle);
    }
}
 
static void *kqueue_timer_open(void)
{
    struct kqueue_timer *timer;
 
    if (!(timer = ao2_alloc(sizeof(*timer), timer_destroy))) {
        ast_log(LOG_ERROR, "Alloc failed for kqueue_timer structure\n");
        return NULL;
    }
 
    if ((timer->handle = kqueue()) < 0) {
        ast_log(LOG_ERROR, "Failed to create kqueue fd: %s\n",
            strerror(errno));
        ao2_ref(timer, -1);
        return NULL;
    }
 
    if (kqueue_timer_init_continuous_event(timer) != 0) {
        ast_log(LOG_ERROR, "Failed to create continuous event: %s\n",
            strerror(errno));
        ao2_ref(timer, -1);
        return NULL;
    }
    ast_debug(5, "[%d]: Create timer\n", timer->handle);
    return timer;
}
 
static void kqueue_timer_close(void *data)
{
    struct kqueue_timer *timer = data;
 
    ast_debug(5, "[%d]: Timer Close\n", timer->handle);
    ao2_ref(timer, -1);
}
 
/*
 * Use the highest precision available that does not overflow
 * the datatype kevent is using for time.
 */
static intptr_t kqueue_scale_period(unsigned int period_ns, int *units)
{
    uint64_t period = period_ns;
    *units = 0;
#ifdef NOTE_NSECONDS
    if (period < INTPTR_MAX) {
        *units = NOTE_NSECONDS;
    } else {
#ifdef NOTE_USECONDS
        period /= 1000;
        if (period < INTPTR_MAX) {
            *units = NOTE_USECONDS;
        } else {
            period /= 1000;
#ifdef NOTE_MSECONDS
            *units = NOTE_MSECONDS;
#endif  /* NOTE_MSECONDS */
        }
#else   /* NOTE_USECONDS */
        period /= 1000000;
#ifdef NOTE_MSECONDS
        *units = NOTE_MSECONDS;
#endif  /* NOTE_MSECONDS */
#endif  /* NOTE_USECONDS */
    }
#else   /* NOTE_NSECONDS */
    period /= 1000000;
#endif
    if (period > INTPTR_MAX) {
        period = INTPTR_MAX;
    }
    return period;
}
 
static int kqueue_timer_set_rate(void *data, unsigned int rate)
{
    struct kevent kev;
    struct kqueue_timer *timer = data;
    uint64_t period_ns;
    int flags;
    int units;
    int retval;
 
    ao2_lock(timer);
 
    if (rate == 0) {
        if (timer->period == 0) {
            ao2_unlock(timer);
            return (0);
        }
        flags = EV_DELETE;
        timer->period = 0;
        units = 0;
    } else  {
        flags = EV_ADD | EV_ENABLE;
        period_ns = (uint64_t)1000000000 / rate;
        timer->period = kqueue_scale_period(period_ns, &units);
    }
    ast_debug(5, "[%d]: Set rate %u:%ju\n",
        timer->handle, units, (uintmax_t)timer->period);
    EV_SET(&kev, timer->handle, EVFILT_TIMER, flags, units,
        timer->period, NULL);
    retval = kevent(timer->handle, &kev, 1, NULL, 0, NULL);
 
    if (retval == -1) {
        ast_log(LOG_ERROR, "[%d]: Error queing timer: %s\n",
            timer->handle, strerror(errno));
    }
 
    ao2_unlock(timer);
 
    return 0;
}
 
static int kqueue_timer_ack(void *data, unsigned int quantity)
{
    static struct timespec ts_nowait = { 0, 0 };
    struct kqueue_timer *timer = data;
    struct kevent kev[2];
    int i, retval;
 
    ao2_lock(timer);
 
    retval = kevent(timer->handle, NULL, 0, kev, 2, &ts_nowait);
    if (retval == -1) {
        ast_log(LOG_ERROR, "[%d]: Error sampling kqueue: %s\n",
            timer->handle, strerror(errno));
        ao2_unlock(timer);
        return -1;
    }
 
    for (i = 0; i < retval; i++) {
        switch (kev[i].filter) {
        case EVFILT_TIMER:
            if (kev[i].data > quantity) {
                ast_log(LOG_ERROR, "[%d]: Missed %ju\n",
                    timer->handle,
                    (uintmax_t)kev[i].data - quantity);
            }
            break;
        case CONTINUOUS_EVFILT_TYPE:
            if (!timer->is_continuous) {
                ast_log(LOG_ERROR,
                    "[%d]: Spurious user event\n",
                    timer->handle);
            }
            break;
        default:
            ast_log(LOG_ERROR, "[%d]: Spurious kevent type %d.\n",
                timer->handle, kev[i].filter);
        }
    }
 
    ao2_unlock(timer);
 
    return 0;
}
 
static int kqueue_timer_enable_continuous(void *data)
{
    struct kqueue_timer *timer = data;
    int retval;
 
    ao2_lock(timer);
 
    if (!timer->is_continuous) {
        ast_debug(5, "[%d]: Enable Continuous\n", timer->handle);
        retval = kqueue_timer_enable_continuous_event(timer);
        if (retval == -1) {
            ast_log(LOG_ERROR,
                "[%d]: Error signaling continuous event: %s\n",
                timer->handle, strerror(errno));
        }
        timer->is_continuous = 1;
    }
 
    ao2_unlock(timer);
 
    return 0;
}
 
static int kqueue_timer_disable_continuous(void *data)
{
    struct kqueue_timer *timer = data;
    int retval;
 
    ao2_lock(timer);
 
    if (timer->is_continuous) {
        ast_debug(5, "[%d]: Disable Continuous\n", timer->handle);
        retval = kqueue_timer_disable_continuous_event(timer);
        if (retval == -1) {
            ast_log(LOG_ERROR,
                "[%d]: Error clearing continuous event: %s\n",
                timer->handle, strerror(errno));
        }
        timer->is_continuous = 0;
    }
 
    ao2_unlock(timer);
 
    return 0;
}
 
static enum ast_timer_event kqueue_timer_get_event(void *data)
{
    struct kqueue_timer *timer = data;
    enum ast_timer_event res;
 
    if (timer->is_continuous) {
        res = AST_TIMING_EVENT_CONTINUOUS;
    } else {
        res = AST_TIMING_EVENT_EXPIRED;
    }
 
    return res;
}
 
static unsigned int kqueue_timer_get_max_rate(void *data)
{
    return INTPTR_MAX > UINT_MAX ? UINT_MAX : INTPTR_MAX;
}
 
static int kqueue_timer_fd(void *data)
{
    struct kqueue_timer *timer = data;
 
    return timer->handle;
}
 
#ifdef TEST_FRAMEWORK
AST_TEST_DEFINE(test_kqueue_timing)
{
    int res = AST_TEST_PASS, i;
    uint64_t diff;
    struct pollfd pfd = { 0, POLLIN, 0 };
    struct kqueue_timer *kt;
    struct timeval start;
 
    switch (cmd) {
    case TEST_INIT:
        info->name = "test_kqueue_timing";
        info->category = "/res/res_timing_kqueue/";
        info->summary = "Test KQueue timing interface";
        info->description = "Verify that the KQueue timing interface correctly generates timing events";
        return AST_TEST_NOT_RUN;
    case TEST_EXECUTE:
        break;
    }
 
    if (!(kt = kqueue_timer_open())) {
        ast_test_status_update(test, "Cannot open timer!\n");
        return AST_TEST_FAIL;
    }
 
    do {
        pfd.fd = kqueue_timer_fd(kt);
        if (kqueue_timer_set_rate(kt, 1000)) {
            ast_test_status_update(test, "Cannot set timer rate to 1000/s\n");
            res = AST_TEST_FAIL;
            break;
        }
        if (ast_poll(&pfd, 1, 1000) < 1) {
            ast_test_status_update(test, "Polling on a kqueue doesn't work\n");
            res = AST_TEST_FAIL;
            break;
        }
        if (pfd.revents != POLLIN) {
            ast_test_status_update(test, "poll() should have returned POLLIN, but instead returned %hd\n", pfd.revents);
            res = AST_TEST_FAIL;
            break;
        }
        if (kqueue_timer_get_event(kt) <= 0) {
            ast_test_status_update(test, "No events generated after a poll returned successfully?!!\n");
            res = AST_TEST_FAIL;
            break;
        }
        if (kqueue_timer_ack(kt, 1) != 0) {
            ast_test_status_update(test, "Acking event failed.\n");
            res = AST_TEST_FAIL;
            break;
        }
 
        kqueue_timer_enable_continuous(kt);
        start = ast_tvnow();
        for (i = 0; i < 100; i++) {
            if (ast_poll(&pfd, 1, 1000) < 1) {
                ast_test_status_update(test, "Polling on a kqueue doesn't work\n");
                res = AST_TEST_FAIL;
                break;
            }
            if (kqueue_timer_get_event(kt) <= 0) {
                ast_test_status_update(test, "No events generated in continuous mode after 1 microsecond?!!\n");
                res = AST_TEST_FAIL;
                break;
            }
            if (kqueue_timer_ack(kt, 1) != 0) {
                ast_test_status_update(test, "Acking event failed.\n");
                res = AST_TEST_FAIL;
                break;
            }
 
        }
        diff = ast_tvdiff_us(ast_tvnow(), start);
        ast_test_status_update(test, "diff is %llu\n", diff);
    } while (0);
    kqueue_timer_close(kt);
    return res;
}
#endif
 
/*!
 * \brief Load the module
 *
 * Module loading including tests for configuration or dependencies.
 * This function can return AST_MODULE_LOAD_FAILURE, AST_MODULE_LOAD_DECLINE,
 * or AST_MODULE_LOAD_SUCCESS. If a dependency or environment variable fails
 * tests return AST_MODULE_LOAD_FAILURE. If the module can not load the
 * configuration file or other non-critical problem return
 * AST_MODULE_LOAD_DECLINE. On success return AST_MODULE_LOAD_SUCCESS.
 */
static int load_module(void)
{
    if (!(timing_funcs_handle = ast_register_timing_interface(&kqueue_timing))) {
        return AST_MODULE_LOAD_DECLINE;
    }
 
    AST_TEST_REGISTER(test_kqueue_timing);
    return AST_MODULE_LOAD_SUCCESS;
}
 
static int unload_module(void)
{
    AST_TEST_UNREGISTER(test_kqueue_timing);
 
    return ast_unregister_timing_interface(timing_funcs_handle);
}
 
AST_MODULE_INFO(ASTERISK_GPL_KEY, AST_MODFLAG_LOAD_ORDER, "KQueue Timing Interface",
    .support_level = AST_MODULE_SUPPORT_EXTENDED,
    .load = load_module,
    .unload = unload_module,
    .load_pri = AST_MODPRI_CHANNEL_DEPEND,
);