core.c

/* Copyright Joyent, Inc. and other Node contributors. All rights reserved.
 *
 * Permission is hereby granted, free of charge, to any person obtaining a copy
 * of this software and associated documentation files (the "Software"), to
 * deal in the Software without restriction, including without limitation the
 * rights to use, copy, modify, merge, publish, distribute, sublicense, and/or
 * sell copies of the Software, and to permit persons to whom the Software is
 * furnished to do so, subject to the following conditions:
 *
 * The above copyright notice and this permission notice shall be included in
 * all copies or substantial portions of the Software.
 *
 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
 * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
 * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
 * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
 * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
 * FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS
 * IN THE SOFTWARE.
 */

#include <assert.h>
#include <limits.h>
#include <stdlib.h>

#include "uv.h"
#include "internal.h"
#include "queue.h"
#include "handle-inl.h"
#include "req-inl.h"
#include "heap-inl.h"

/* uv_once initialization guards */
static uv_once_t uv_init_guard_ = UV_ONCE_INIT;

static void* uv__loops[2];
static uv_mutex_t uv__loops_lock;

static void uv__loops_init(void) {
  uv_mutex_init(&uv__loops_lock);
  QUEUE_INIT(&uv__loops);
}

static void uv__loops_add(uv_loop_t* loop) {
  uv_mutex_lock(&uv__loops_lock);
  QUEUE_INSERT_TAIL(&uv__loops, &loop->loops_queue);
  uv_mutex_unlock(&uv__loops_lock);
}

static void uv__loops_remove(uv_loop_t* loop) {
  uv_mutex_lock(&uv__loops_lock);
  QUEUE_REMOVE(&loop->loops_queue);
  uv_mutex_unlock(&uv__loops_lock);
}

void uv__wake_all_loops() {
  QUEUE* q;

  uv_mutex_lock(&uv__loops_lock);
  QUEUE_FOREACH(q, &uv__loops) {
    uv_loop_t* loop = QUEUE_DATA(q, uv_loop_t, loops_queue);
    if (loop->iocp != INVALID_HANDLE_VALUE)
      PostQueuedCompletionStatus(loop->iocp, 0, 0, NULL);
  }
  uv_mutex_unlock(&uv__loops_lock);
}

static void uv_init(void) {
  /* Tell Windows that we will handle critical errors. */
  SetErrorMode(SEM_FAILCRITICALERRORS | SEM_NOGPFAULTERRORBOX |
               SEM_NOOPENFILEERRORBOX);

  /* Initialize tracking of all uv loops */
  uv__loops_init();

  /* Fetch winapi function pointers. This must be done first because other
   * initialization code might need these function pointers to be loaded.
   */
  uv_winapi_init();

  /* Initialize winsock */
  uv_winsock_init();

  /* Initialize signal stuff */
  uv_signals_init();

  /* Initialize console */
  uv_console_init();

  /* Initialize utilities */
  uv__util_init();

  /* Initialize system wakeup detection */
  uv__init_detect_system_wakeup();
}


/* The number of milliseconds in one second. */
#define UV__MILLISEC 1000


void uv_update_time(uv_loop_t* loop) {
  uint64_t new_time = uv__hrtime(UV__MILLISEC);
  assert(new_time >= loop->time);
  loop->time = new_time;
}


int uv_loop_init(uv_loop_t* loop) {
  int err;

  /* Initialize libuv itself first */
  uv__once_init();

  /* Create an I/O completion port */
  loop->iocp = CreateIoCompletionPort(INVALID_HANDLE_VALUE, NULL, 0, 1);
  if (loop->iocp == NULL)
    return uv_translate_sys_error(GetLastError());

  /* To prevent uninitialized memory access, loop->time must be initialized
   * to zero before calling uv_update_time for the first time.
   */
  loop->time = 0;
  uv_update_time(loop);

  QUEUE_INIT(&loop->wq);
  QUEUE_INIT(&loop->handle_queue);
  QUEUE_INIT(&loop->active_reqs);
  loop->active_handles = 0;

  loop->pending_reqs_tail = NULL;

  loop->endgame_handles = NULL;

  heap_init((struct heap*) &loop->timer_heap);
  loop->timer_counter = 0;

  QUEUE_INIT(&loop->check_handles);
  QUEUE_INIT(&loop->prepare_handles);
  QUEUE_INIT(&loop->idle_handles);

  QUEUE_INIT(&loop->async_handles);
  UV_REQ_INIT(&loop->async_req, UV_WAKEUP);

  memset(&loop->poll_peer_sockets, 0, sizeof loop->poll_peer_sockets);

  loop->stop_flag = 0;

  err = uv_mutex_init(&loop->wq_mutex);
  if (err)
    goto fail_mutex_init;

  err = uv_async_init(loop, &loop->wq_async, uv__work_done);
  if (err)
    goto fail_async_init;

  uv__handle_unref(&loop->wq_async);
  loop->wq_async.flags |= UV__HANDLE_INTERNAL;

  QUEUE_INIT(&loop->loops_queue);
  uv__loops_add(loop);

  return 0;

fail_async_init:
  uv_mutex_destroy(&loop->wq_mutex);

fail_mutex_init:
  CloseHandle(loop->iocp);
  loop->iocp = INVALID_HANDLE_VALUE;

  return err;
}


void uv__once_init(void) {
  uv_once(&uv_init_guard_, uv_init);
}


void uv__loop_close(uv_loop_t* loop) {
  size_t i;

  uv__loops_remove(loop);

  /* close the async handle without needing an extra loop iteration */
  assert(!loop->wq_async.async_sent);
  loop->wq_async.close_cb = NULL;
  uv__handle_closing(&loop->wq_async);
  uv__handle_close(&loop->wq_async);

  for (i = 0; i < ARRAY_SIZE(loop->poll_peer_sockets); i++) {
    SOCKET sock = loop->poll_peer_sockets[i];
    if (sock != 0 && sock != INVALID_SOCKET)
      closesocket(sock);
  }

  uv_mutex_lock(&loop->wq_mutex);
  assert(QUEUE_EMPTY(&loop->wq) && "thread pool work queue not empty!");
  assert(!uv__has_active_reqs(loop));
  uv_mutex_unlock(&loop->wq_mutex);
  uv_mutex_destroy(&loop->wq_mutex);

  CloseHandle(loop->iocp);
}


int uv__loop_configure(uv_loop_t* loop, uv_loop_option option, va_list ap) {
  return UV_ENOSYS;
}


uv_os_fd_t uv_backend_fd(const uv_loop_t* loop) {
  return loop->iocp;
}


int uv_backend_timeout(const uv_loop_t* loop) {
  if (loop->stop_flag != 0)
    return 0;

  if (!uv__has_active_handles(loop) && !uv__has_active_reqs(loop))
    return 0;

  if (loop->pending_reqs_tail)
    return 0;

  if (loop->endgame_handles)
    return 0;

  if (!QUEUE_EMPTY(&loop->idle_handles))
    return 0;

  return uv__next_timeout(loop);
}


static void uv__loop_poll_wine(uv_loop_t* loop, int timeout) {
  DWORD bytes;
  ULONG_PTR key;
  OVERLAPPED* overlapped;
  uv_req_t* req;
  int repeat;
  uint64_t timeout_time;

  timeout_time = loop->time + timeout;

  for (repeat = 0; ; repeat++) {
    GetQueuedCompletionStatus(loop->iocp,
                              &bytes,
                              &key,
                              &overlapped,
                              timeout);

    if (overlapped) {
      /* Package was dequeued */
      req = container_of(overlapped, uv_req_t, u.io.overlapped);
      uv_insert_pending_req(loop, req);

      /* Some time might have passed waiting for I/O,
       * so update the loop time here.
       */
      uv_update_time(loop);
    } else if (GetLastError() != WAIT_TIMEOUT) {
      /* Serious error */
      uv_fatal_error(GetLastError(), "GetQueuedCompletionStatus");
    } else if (timeout > 0) {
      /* GetQueuedCompletionStatus can occasionally return a little early.
       * Make sure that the desired timeout target time is reached.
       */
      uv_update_time(loop);
      if (timeout_time > loop->time) {
        timeout = (DWORD)(timeout_time - loop->time);
        /* The first call to GetQueuedCompletionStatus should return very
         * close to the target time and the second should reach it, but
         * this is not stated in the documentation. To make sure a busy
         * loop cannot happen, the timeout is increased exponentially
         * starting on the third round.
         */
        timeout += repeat ? (1 << (repeat - 1)) : 0;
        continue;
      }
    }
    break;
  }
}


static void uv__loop_poll(uv_loop_t* loop, int timeout) {
  BOOL success;
  uv_req_t* req;
  OVERLAPPED_ENTRY overlappeds[128];
  ULONG count;
  ULONG i;
  int repeat;
  uint64_t timeout_time;

  timeout_time = loop->time + timeout;

  for (repeat = 0; ; repeat++) {
    success = GetQueuedCompletionStatusEx(loop->iocp,
                                          overlappeds,
                                          ARRAY_SIZE(overlappeds),
                                          &count,
                                          timeout,
                                          FALSE);

    if (success) {
      for (i = 0; i < count; i++) {
        /* Package was dequeued, but see if it is not a empty package
         * meant only to wake us up.
         */
        if (overlappeds[i].lpOverlapped) {
          req = container_of(overlappeds[i].lpOverlapped, uv_req_t, u.io.overlapped);
          uv_insert_pending_req(loop, req);
        }
      }

      /* Some time might have passed waiting for I/O,
       * so update the loop time here.
       */
      uv_update_time(loop);
    } else if (GetLastError() != WAIT_TIMEOUT) {
      /* Serious error */
      uv_fatal_error(GetLastError(), "GetQueuedCompletionStatusEx");
    } else if (timeout > 0) {
      /* GetQueuedCompletionStatus can occasionally return a little early.
       * Make sure that the desired timeout target time is reached.
       */
      uv_update_time(loop);
      if (timeout_time > loop->time) {
        timeout = (DWORD)(timeout_time - loop->time);
        /* The first call to GetQueuedCompletionStatus should return very
         * close to the target time and the second should reach it, but
         * this is not stated in the documentation. To make sure a busy
         * loop cannot happen, the timeout is increased exponentially
         * starting on the third round.
         */
        timeout += repeat ? (1 << (repeat - 1)) : 0;
        continue;
      }
    }
    break;
  }
}


static int uv__loop_alive(const uv_loop_t* loop) {
  return loop->active_handles > 0 ||
         !QUEUE_EMPTY(&loop->active_reqs) ||
         loop->endgame_handles != NULL;
}


int uv_loop_alive(const uv_loop_t* loop) {
    return uv__loop_alive(loop);
}


int uv_run(uv_loop_t *loop, uv_run_mode mode) {
  int timeout;
  int r;
  int ran_pending;

  r = uv__loop_alive(loop);
  if (!r)
    uv_update_time(loop);

  while (r != 0 && loop->stop_flag == 0) {
    uv_update_time(loop);
    uv__run_timers(loop);

    ran_pending = uv_process_reqs(loop);
    uv__run_idle(loop);
    uv__run_prepare(loop);

    timeout = 0;
    if ((mode == UV_RUN_ONCE && !ran_pending) || mode == UV_RUN_DEFAULT)
      timeout = uv_backend_timeout(loop);

    if (pGetQueuedCompletionStatusEx)
      uv__loop_poll(loop, timeout == -1 ? INFINITE : timeout);
    else
      uv__loop_poll_wine(loop, timeout == -1 ? INFINITE : timeout);

    uv__run_check(loop);
    uv_process_endgames(loop);

    if (mode == UV_RUN_ONCE) {
      /* UV_RUN_ONCE implies forward progress: at least one callback must have
       * been invoked when it returns. uv__io_poll() can return without doing
       * I/O (meaning: no callbacks) when its timeout expires - which means we
       * have pending timers that satisfy the forward progress constraint.
       *
       * UV_RUN_NOWAIT makes no guarantees about progress so it's omitted from
       * the check.
       */
      uv__run_timers(loop);
    }

    r = uv__loop_alive(loop);
    if (mode == UV_RUN_ONCE || mode == UV_RUN_NOWAIT)
      break;
  }

  /* The if statement lets the compiler compile it to a conditional store.
   * Avoids dirtying a cache line.
   */
  if (loop->stop_flag != 0)
    loop->stop_flag = 0;

  return r;
}


int uv_fileno(const uv_handle_t* handle, uv_os_fd_t* fd) {
  uv_os_fd_t fd_out;

  switch (handle->type) {
  case UV_TCP:
    fd_out = (uv_os_fd_t)((uv_tcp_t*) handle)->socket;
    break;

  case UV_NAMED_PIPE:
    fd_out = ((uv_pipe_t*) handle)->handle;
    break;

  case UV_TTY:
    fd_out = ((uv_tty_t*) handle)->handle;
    break;

  case UV_UDP:
    fd_out = (uv_os_fd_t)((uv_udp_t*) handle)->socket;
    break;

  case UV_POLL:
    fd_out = (uv_os_fd_t)((uv_poll_t*) handle)->socket;
    break;

  default:
    return UV_EINVAL;
  }

  if (uv_is_closing(handle) || fd_out == INVALID_HANDLE_VALUE)
    return UV_EBADF;

  *fd = fd_out;
  return 0;
}


int uv__socket_sockopt(uv_handle_t* handle, int optname, int* value) {
  int r;
  int len;
  SOCKET socket;

  if (handle == NULL || value == NULL)
    return UV_EINVAL;

  if (handle->type == UV_TCP)
    socket = ((uv_tcp_t*) handle)->socket;
  else if (handle->type == UV_UDP)
    socket = ((uv_udp_t*) handle)->socket;
  else
    return UV_ENOTSUP;

  len = sizeof(*value);

  if (*value == 0)
    r = getsockopt(socket, SOL_SOCKET, optname, (char*) value, &len);
  else
    r = setsockopt(socket, SOL_SOCKET, optname, (const char*) value, len);

  if (r == SOCKET_ERROR)
    return uv_translate_sys_error(WSAGetLastError());

  return 0;
}


int uv_cpumask_size(void) {
#if defined(_WIN64)
  return 64;
#else
  return 32;
#endif
}