timing.c

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/*
 * Asterisk -- An open source telephony toolkit.
 *
 * Copyright (C) 2008 - 2009, Digium, Inc.
 *
 * Kevin P. Fleming <[email protected]>
 * Russell Bryant <[email protected]>
 *
 * 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 <[email protected]>
 * \author Russell Bryant <[email protected]>
 */

/*** 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));
}