src/core/iomgr/iomgr.c

/*
 *
 * Copyright 2015, Google Inc.
 * All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions are
 * met:
 *
 *     * Redistributions of source code must retain the above copyright
 * notice, this list of conditions and the following disclaimer.
 *     * Redistributions in binary form must reproduce the above
 * copyright notice, this list of conditions and the following disclaimer
 * in the documentation and/or other materials provided with the
 * distribution.
 *     * Neither the name of Google Inc. nor the names of its
 * contributors may be used to endorse or promote products derived from
 * this software without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
 * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
 * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
 * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
 * OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
 * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
 * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
 * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 *
 */

#include "src/core/iomgr/iomgr.h"

#include <stdlib.h>
#include <string.h>

#include <grpc/support/alloc.h>
#include <grpc/support/log.h>
#include <grpc/support/string_util.h>
#include <grpc/support/sync.h>
#include <grpc/support/thd.h>

#include "src/core/iomgr/iomgr_internal.h"
#include "src/core/iomgr/alarm_internal.h"
#include "src/core/support/string.h"

static gpr_mu g_mu;
static gpr_cv g_rcv;
static int g_shutdown;
static grpc_iomgr_object g_root_object;

void grpc_kick_poller(void) {
  /* Empty. The background callback executor polls periodically. The activity
   * the kicker is trying to draw the executor's attention to will be picked up
   * either by one of the periodic wakeups or by one of the polling application
   * threads. */
}

void grpc_iomgr_init(void) {
  g_shutdown = 0;
  gpr_mu_init(&g_mu);
  gpr_cv_init(&g_rcv);
  grpc_alarm_list_init(gpr_now(GPR_CLOCK_MONOTONIC));
  g_root_object.next = g_root_object.prev = &g_root_object;
  g_root_object.name = "root";
  grpc_iomgr_platform_init();
}

static size_t count_objects(void) {
  grpc_iomgr_object *obj;
  size_t n = 0;
  for (obj = g_root_object.next; obj != &g_root_object; obj = obj->next) {
    n++;
  }
  return n;
}

static void dump_objects(const char *kind) {
  grpc_iomgr_object *obj;
  for (obj = g_root_object.next; obj != &g_root_object; obj = obj->next) {
    gpr_log(GPR_DEBUG, "%s OBJECT: %s %p", kind, obj->name, obj);
  }
}

void grpc_iomgr_shutdown(void) {
  gpr_timespec shutdown_deadline = gpr_time_add(
      gpr_now(GPR_CLOCK_REALTIME), gpr_time_from_seconds(10, GPR_TIMESPAN));
  gpr_timespec last_warning_time = gpr_now(GPR_CLOCK_REALTIME);
  grpc_call_list call_list = GRPC_CALL_LIST_INIT;

  gpr_mu_lock(&g_mu);
  g_shutdown = 1;
  while (g_root_object.next != &g_root_object) {
    if (gpr_time_cmp(
            gpr_time_sub(gpr_now(GPR_CLOCK_REALTIME), last_warning_time),
            gpr_time_from_seconds(1, GPR_TIMESPAN)) >= 0) {
      if (g_root_object.next != &g_root_object) {
        gpr_log(GPR_DEBUG, "Waiting for %d iomgr objects to be destroyed",
                count_objects());
      }
      last_warning_time = gpr_now(GPR_CLOCK_REALTIME);
    }
    if (grpc_alarm_check(gpr_inf_future(GPR_CLOCK_MONOTONIC), NULL,
                         &call_list)) {
      gpr_mu_unlock(&g_mu);
      grpc_call_list_run(&call_list);
      gpr_mu_lock(&g_mu);
      continue;
    }
    if (g_root_object.next != &g_root_object) {
      int timeout = 0;
      gpr_timespec short_deadline = gpr_time_add(
          gpr_now(GPR_CLOCK_REALTIME), gpr_time_from_millis(100, GPR_TIMESPAN));
      if (gpr_cv_wait(&g_rcv, &g_mu, short_deadline)) {
        if (gpr_time_cmp(gpr_now(GPR_CLOCK_REALTIME), shutdown_deadline) > 0) {
          timeout = 1;
          break;
        }
      }
      if (timeout && g_root_object.next != &g_root_object) {
        gpr_log(GPR_DEBUG,
                "Failed to free %d iomgr objects before shutdown deadline: "
                "memory leaks are likely",
                count_objects());
        dump_objects("LEAKED");
        break;
      }
    }
  }
  gpr_mu_unlock(&g_mu);

  grpc_alarm_list_shutdown(&call_list);
  grpc_call_list_run(&call_list);

  grpc_iomgr_platform_shutdown();
  gpr_mu_destroy(&g_mu);
  gpr_cv_destroy(&g_rcv);
}

void grpc_iomgr_register_object(grpc_iomgr_object *obj, const char *name) {
  obj->name = gpr_strdup(name);
  gpr_mu_lock(&g_mu);
  obj->next = &g_root_object;
  obj->prev = g_root_object.prev;
  obj->next->prev = obj->prev->next = obj;
  gpr_mu_unlock(&g_mu);
}

void grpc_iomgr_unregister_object(grpc_iomgr_object *obj) {
  gpr_mu_lock(&g_mu);
  obj->next->prev = obj->prev;
  obj->prev->next = obj->next;
  gpr_cv_signal(&g_rcv);
  gpr_mu_unlock(&g_mu);
  gpr_free(obj->name);
}

void grpc_closure_init(grpc_closure *closure, grpc_iomgr_cb_func cb,
                       void *cb_arg) {
  closure->cb = cb;
  closure->cb_arg = cb_arg;
  closure->next = NULL;
}

void grpc_call_list_add(grpc_call_list *call_list, grpc_closure *closure,
                        int success) {
  if (!closure) return;
  closure->next = NULL;
  closure->success = success;
  if (!call_list->head) {
    call_list->head = closure;
  } else {
    call_list->tail->next = closure;
  }
  call_list->tail = closure;
}

void grpc_call_list_run(grpc_call_list *call_list) {
  while (!grpc_call_list_empty(*call_list)) {
    grpc_closure *c = call_list->head;
    call_list->head = call_list->tail = NULL;
    while (c) {
      grpc_closure *next = c->next;
      c->cb(c->cb_arg, c->success, call_list);
      c = next;
    }
  }
}

int grpc_call_list_empty(grpc_call_list call_list) {
  return call_list.head == NULL;
}

void grpc_call_list_move(grpc_call_list *src, grpc_call_list *dst) {
  if (dst->head == NULL) {
    *dst = *src;
    return;
  }
  if (src->head == NULL) {
    return;
  }
  dst->tail->next = src->head;
  dst->tail = src->tail;
}