timing.c

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/*
 * Asterisk -- An open source telephony toolkit.
 *
 * Copyright (C) 2008 - 2009, Digium, Inc.
 *
 * Kevin P. Fleming <kpfleming@digium.com>
 * Russell Bryant <russell@digium.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
 *
 * \brief Timing source management
 *
 * \author Kevin P. Fleming <kpfleming@digium.com>
 * \author Russell Bryant <russell@digium.com>
 */
 
/*** MODULEINFO
    <support_level>core</support_level>
 ***/
 
#include "asterisk.h"
 
#include "asterisk/_private.h"
 
#include "asterisk/timing.h"
#include "asterisk/lock.h"
#include "asterisk/cli.h"
#include "asterisk/utils.h"
#include "asterisk/time.h"
#include "asterisk/heap.h"
#include "asterisk/module.h"
#include "asterisk/poll-compat.h"
 
struct timing_holder {
    /*! Do _not_ move this from the beginning of the struct. */
    ssize_t __heap_index;
    struct ast_module *mod;
    struct ast_timing_interface *iface;
};
 
static struct ast_heap *timing_interfaces;
 
struct ast_timer {
    void *data;
    struct timing_holder *holder;
};
 
static int timing_holder_cmp(void *_h1, void *_h2)
{
    struct timing_holder *h1 = _h1;
    struct timing_holder *h2 = _h2;
 
    if (h1->iface->priority > h2->iface->priority) {
        return 1;
    } else if (h1->iface->priority == h2->iface->priority) {
        return 0;
    } else {
        return -1;
    }
}
 
void *_ast_register_timing_interface(struct ast_timing_interface *funcs,
                     struct ast_module *mod)
{
    struct timing_holder *h;
 
    if (!funcs->timer_open ||
        !funcs->timer_close ||
        !funcs->timer_set_rate ||
        !funcs->timer_ack ||
        !funcs->timer_get_event ||
        !funcs->timer_get_max_rate ||
        !funcs->timer_enable_continuous ||
        !funcs->timer_disable_continuous ||
        !funcs->timer_fd) {
        return NULL;
    }
 
    if (!(h = ast_calloc(1, sizeof(*h)))) {
        return NULL;
    }
 
    h->iface = funcs;
    h->mod = mod;
 
    ast_heap_wrlock(timing_interfaces);
    ast_heap_push(timing_interfaces, h);
    ast_heap_unlock(timing_interfaces);
 
    return h;
}
 
int ast_unregister_timing_interface(void *handle)
{
    struct timing_holder *h = handle;
    int res = -1;
 
    ast_heap_wrlock(timing_interfaces);
    h = ast_heap_remove(timing_interfaces, h);
    ast_heap_unlock(timing_interfaces);
 
    if (h) {
        ast_free(h);
        h = NULL;
        res = 0;
    }
 
    return res;
}
 
struct ast_timer *ast_timer_open(void)
{
    void *data = NULL;
    struct timing_holder *h;
    struct ast_timer *t = NULL;
    int idx = 1;
 
    ast_heap_rdlock(timing_interfaces);
 
    while ((h = ast_heap_peek(timing_interfaces, idx))) {
        if (ast_module_running_ref(h->mod)) {
            data = h->iface->timer_open();
            break;
        }
        idx++;
    }
 
    if (data) {
        if (!(t = ast_calloc(1, sizeof(*t)))) {
            h->iface->timer_close(data);
            ast_module_unref(h->mod);
        } else {
            t->data = data;
            t->holder = h;
        }
    }
 
    ast_heap_unlock(timing_interfaces);
 
    return t;
}
 
void ast_timer_close(struct ast_timer *handle)
{
    handle->holder->iface->timer_close(handle->data);
    ast_module_unref(handle->holder->mod);
    ast_free(handle);
}
 
int ast_timer_fd(const struct ast_timer *handle)
{
    return handle->holder->iface->timer_fd(handle->data);
}
 
int ast_timer_set_rate(const struct ast_timer *handle, unsigned int rate)
{
    return handle->holder->iface->timer_set_rate(handle->data, rate);
}
 
int ast_timer_ack(const struct ast_timer *handle, unsigned int quantity)
{
    return handle->holder->iface->timer_ack(handle->data, quantity);
}
 
int ast_timer_enable_continuous(const struct ast_timer *handle)
{
    return handle->holder->iface->timer_enable_continuous(handle->data);
}
 
int ast_timer_disable_continuous(const struct ast_timer *handle)
{
    return handle->holder->iface->timer_disable_continuous(handle->data);
}
 
enum ast_timer_event ast_timer_get_event(const struct ast_timer *handle)
{
    return handle->holder->iface->timer_get_event(handle->data);
}
 
unsigned int ast_timer_get_max_rate(const struct ast_timer *handle)
{
    return handle->holder->iface->timer_get_max_rate(handle->data);
}
 
const char *ast_timer_get_name(const struct ast_timer *handle)
{
    return handle->holder->iface->name;
}
 
static char *timing_test(struct ast_cli_entry *e, int cmd, struct ast_cli_args *a)
{
    struct ast_timer *timer;
    int count = 0;
    struct timeval start, end;
    unsigned int test_rate = 50;
 
    switch (cmd) {
    case CLI_INIT:
        e->command = "timing test";
        e->usage = "Usage: timing test <rate>\n"
                   "   Test a timer with a specified rate, 50/sec by default.\n"
                   "";
        return NULL;
    case CLI_GENERATE:
        return NULL;
    }
 
    if (a->argc != 2 && a->argc != 3) {
        return CLI_SHOWUSAGE;
    }
 
    if (a->argc == 3) {
        unsigned int rate;
        if (sscanf(a->argv[2], "%30u", &rate) == 1) {
            test_rate = rate;
        } else {
            ast_cli(a->fd, "Invalid rate '%s', using default of %u\n", a->argv[2], test_rate);
        }
    }
 
    ast_cli(a->fd, "Attempting to test a timer with %u ticks per second.\n", test_rate);
 
    if (!(timer = ast_timer_open())) {
        ast_cli(a->fd, "Failed to open timing fd\n");
        return CLI_FAILURE;
    }
 
    ast_cli(a->fd, "Using the '%s' timing module for this test.\n", timer->holder->iface->name);
 
    start = ast_tvnow();
 
    ast_timer_set_rate(timer, test_rate);
 
    while (ast_tvdiff_ms((end = ast_tvnow()), start) < 1000) {
        int res;
        struct pollfd pfd = {
            .fd = ast_timer_fd(timer),
            .events = POLLIN | POLLPRI,
        };
 
        res = ast_poll(&pfd, 1, 100);
 
        if (res == 1) {
            count++;
            if (ast_timer_ack(timer, 1) < 0) {
                ast_cli(a->fd, "Timer failed to acknowledge.\n");
                ast_timer_close(timer);
                return CLI_FAILURE;
            }
        } else if (!res) {
            ast_cli(a->fd, "poll() timed out!  This is bad.\n");
        } else if (errno != EAGAIN && errno != EINTR) {
            ast_cli(a->fd, "poll() returned error: %s\n", strerror(errno));
        }
    }
 
    ast_timer_close(timer);
    timer = NULL;
 
    ast_cli(a->fd, "It has been %" PRIi64 " milliseconds, and we got %d timer ticks\n",
        ast_tvdiff_ms(end, start), count);
 
    return CLI_SUCCESS;
}
 
static struct ast_cli_entry cli_timing[] = {
    AST_CLI_DEFINE(timing_test, "Run a timing test"),
};
 
static void timing_shutdown(void)
{
    ast_cli_unregister_multiple(cli_timing, ARRAY_LEN(cli_timing));
 
    ast_heap_destroy(timing_interfaces);
    timing_interfaces = NULL;
}
 
int ast_timing_init(void)
{
    if (!(timing_interfaces = ast_heap_create(2, timing_holder_cmp, 0))) {
        return -1;
    }
 
    ast_register_cleanup(timing_shutdown);
 
    return ast_cli_register_multiple(cli_timing, ARRAY_LEN(cli_timing));
}