/*
 * Copyright (c) 2015 Cisco and/or its affiliates.
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at:
 *
 *     http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */
/*
 * input.c: Unix file input
 *
 * Copyright (c) 2008 Eliot Dresselhaus
 *
 * 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 <vlib/vlib.h>
#include <vlib/unix/unix.h>
#include <signal.h>
#include <unistd.h>
#include <vppinfra/tw_timer_1t_3w_1024sl_ov.h>

/* FIXME autoconf */
#define HAVE_LINUX_EPOLL

#ifdef HAVE_LINUX_EPOLL

#include <sys/epoll.h>

typedef struct
{
  CLIB_CACHE_LINE_ALIGN_MARK (cacheline0);
  int epoll_fd;
  struct epoll_event *epoll_events;
  int n_epoll_fds;

  /* Statistics. */
  u64 epoll_files_ready;
  u64 epoll_waits;
} linux_epoll_main_t;

static linux_epoll_main_t *linux_epoll_mains = 0;

static void
linux_epoll_file_update (clib_file_t * f, clib_file_update_type_t update_type)
{
  clib_file_main_t *fm = &file_main;
  linux_epoll_main_t *em = vec_elt_at_index (linux_epoll_mains,
					     f->polling_thread_index);
  struct epoll_event e = { 0 };
  int op, add_del = 0;

  e.events = EPOLLIN;
  if (f->flags & UNIX_FILE_DATA_AVAILABLE_TO_WRITE)
    e.events |= EPOLLOUT;
  if (f->flags & UNIX_FILE_EVENT_EDGE_TRIGGERED)
    e.events |= EPOLLET;
  e.data.u32 = f - fm->file_pool;

  op = -1;

  switch (update_type)
    {
    case UNIX_FILE_UPDATE_ADD:
      op = EPOLL_CTL_ADD;
      add_del = 1;
      break;

    case UNIX_FILE_UPDATE_MODIFY:
      op = EPOLL_CTL_MOD;
      break;

    case UNIX_FILE_UPDATE_DELETE:
      op = EPOLL_CTL_DEL;
      add_del = -1;
      break;

    default:
      clib_warning ("unknown update_type %d", update_type);
      return;
    }

  /* worker threads open epoll fd only if needed */
  if (update_type == UNIX_FILE_UPDATE_ADD && em->epoll_fd == -1)
    {
      em->epoll_fd = epoll_create (1);
      if (em->epoll_fd < 0)
	{
	  clib_unix_warning ("epoll_create");
	  return;
	}
      em->n_epoll_fds = 0;
    }

  if (epoll_ctl (em->epoll_fd, op, f->file_descriptor, &e) < 0)
    {
      clib_unix_warning ("epoll_ctl");
      return;
    }

  em->n_epoll_fds += add_del;

  if (em->n_epoll_fds == 0)
    {
      close (em->epoll_fd);
      em->epoll_fd = -1;
    }
}

static_always_inline uword
linux_epoll_input_inline (vlib_main_t * vm, vlib_node_runtime_t * node,
			  vlib_frame_t * frame, u32 thread_index)
{
  unix_main_t *um = &unix_main;
  clib_file_main_t *fm = &file_main;
  linux_epoll_main_t *em = vec_elt_at_index (linux_epoll_mains, thread_index);
  struct epoll_event *e;
  int n_fds_ready;
  int is_main = (thread_index == 0);

  {
    vlib_node_main_t *nm = &vm->node_main;
    u32 ticks_until_expiration;
    f64 timeout;
    f64 now;
    int timeout_ms = 0, max_timeout_ms = 10;
    f64 vector_rate = vlib_last_vectors_per_main_loop (vm);

    if (is_main == 0)
      now = vlib_time_now (vm);

    /*
     * If we've been asked for a fixed-sleep between main loop polls,
     * do so right away.
     */
    if (PREDICT_FALSE (is_main && um->poll_sleep_usec))
      {
	struct timespec ts, tsrem;
	timeout = 0;
	timeout_ms = 0;
	node->input_main_loops_per_call = 0;
	ts.tv_sec = 0;
	ts.tv_nsec = 1000 * um->poll_sleep_usec;

	while (nanosleep (&ts, &tsrem) < 0)
	  {
	    ts = tsrem;
	  }
      }
    /* If we're not working very hard, decide how long to sleep */
    else if (is_main && vector_rate < 2 && vm->api_queue_nonempty == 0
	     && nm->input_node_counts_by_state[VLIB_NODE_STATE_POLLING] == 0)
      {
	ticks_until_expiration = TW (tw_timer_first_expires_in_ticks)
	  ((TWT (tw_timer_wheel) *) nm->timing_wheel);

	/* Nothing on the fast wheel, sleep 10ms */
	if (ticks_until_expiration == TW_SLOTS_PER_RING)
	  {
	    timeout = 10e-3;
	    timeout_ms = max_timeout_ms;
	  }
	else
	  {
	    timeout = (f64) ticks_until_expiration *1e-5;
	    if (timeout < 1e-3)
	      timeout_ms = 0;
	    else
	      {
		timeout_ms = timeout * 1e3;
		/* Must be between 1 and 10 ms. */
		timeout_ms = clib_max (1, timeout_ms);
		timeout_ms = clib_min (max_timeout_ms, timeout_ms);
	      }
	  }
	node->input_main_loops_per_call = 0;
      }
    else if (is_main == 0 && vector_rate < 2 &&
	     (vlib_get_first_main ()->time_last_barrier_release + 0.5 < now) &&<style>
@media only all and (prefers-color-scheme: dark) {
.highlight .hll { background-color: #49483e }
.highlight .c { color: #75715e } /* Comment */
.highlight .err { color: #960050; background-color: #1e0010 } /* Error */
.highlight .k { color: #66d9ef } /* Keyword */
.highlight .l { color: #ae81ff } /* Literal */
.highlight .n { color: #f8f8f2 } /* Name */
.highlight .o { color: #f92672 } /* Operator */
.highlight .p { color: #f8f8f2 } /* Punctuation */
.highlight .ch { color: #75715e } /* Comment.Hashbang */
.highlight .cm { color: #75715e } /* Comment.Multiline */
.highlight .cp { color: #75715e } /* Comment.Preproc */
.highlight .cpf { color: #75715e } /* Comment.PreprocFile */
.highlight .c1 { color: #75715e } /* Comment.Single */
.highlight .cs { color: #75715e } /* Comment.Special */
.highlight .gd { color: #f92672 } /* Generic.Deleted */
.highlight .ge { font-style: italic } /* Generic.Emph */
.highlight .gi { color: #a6e22e } /* Generic.Inserted */
.highlight .gs { font-weight: bold } /* Generic.Strong */
.highlight .gu { color: #75715e } /* Generic.Subheading */
.highlight .kc { color: #66d9ef } /* Keyword.Constant */
.highlight .kd { color: #66d9ef } /* Keyword.Declaration */
.highlight .kn { color: #f92672 } /* Keyword.Namespace */
.highlight .kp { color: #66d9ef } /* Keyword.Pseudo */
.highlight .kr { color: #66d9ef } /* Keyword.Reserved */
.highlight .kt { color: #66d9ef } /* Keyword.Type */
.highlight .ld { color: #e6db74 } /* Literal.Date */
.highlight .m { color: #ae81ff } /* Literal.Number */
.highlight .s { color: #e6db74 } /* Literal.String */
.highlight .na { color: #a6e22e } /* Name.Attribute */
.highlight .nb { color: #f8f8f2 } /* Name.Builtin */
.highlight .nc { color: #a6e22e } /* Name.Class */
.highlight .no { color: #66d9ef } /* Name.Constant */
.highlight .nd { color: #a6e22e } /* Name.Decorator */
.highlight .ni { color: #f8f8f2 } /* Name.Entity */
.highlight .ne { color: #a6e22e } /* Name.Exception */
.highlight .nf { color: #a6e22e } /* Name.Function */
.highlight .nl { color: #f8f8f2 } /* Name.Label */
.highlight .nn { color: #f8f8f2 } /* Name.Namespace */
.highlight .nx { color: #a6e22e } /* Name.Other */
.highlight .py { color: #f8f8f2 } /* Name.Property */
.highlight .nt { color: #f92672 } /* Name.Tag */
.highlight .nv { color: #f8f8f2 } /* Name.Variable */
.highlight .ow { color: #f92672 } /* Operator.Word */
.highlight .w { color: #f8f8f2 } /* Text.Whitespace */
.highlight .mb { color: #ae81ff } /* Literal.Number.Bin */
.highlight .mf { color: #ae81ff } /* Literal.Number.Float */
.highlight .mh { color: #ae81ff } /* Literal.Number.Hex */
.highlight .mi { color: #ae81ff } /* Literal.Number.Integer */
.highlight .mo { color: #ae81ff } /* Literal.Number.Oct */
.highlight .sa { color: #e6db74 } /* Literal.String.Affix */
.highlight .sb { color: #e6db74 } /* Literal.String.Backtick */
.highlight .sc { color: #e6db74 } /* Literal.String.Char */
.highlight .dl { color: #e6db74 } /* Literal.String.Delimiter */
.highlight .sd { color: #e6db74 } /* Literal.String.Doc */
.highlight .s2 { color: #e6db74 } /* Literal.String.Double */
.highlight .se { color: #ae81ff } /* Literal.String.Escape */
.highlight .sh { color: #e6db74 } /* Literal.String.Heredoc */
.highlight .si { color: #e6db74 } /* Literal.String.Interpol */
.highlight .sx { color: #e6db74 } /* Literal.String.Other */
.highlight .sr { color: #e6db74 } /* Literal.String.Regex */
.highlight .s1 { color: #e6db74 } /* Literal.String.Single */
.highlight .ss { color: #e6db74 } /* Literal.String.Symbol */
.highlight .bp { color: #f8f8f2 } /* Name.Builtin.Pseudo */
.highlight .fm { color: #a6e22e } /* Name.Function.Magic */
.highlight .vc { color: #f8f8f2 } /* Name.Variable.Class */
.highlight .vg { color: #f8f8f2 } /* Name.Variable.Global */
.highlight .vi { color: #f8f8f2 } /* Name.Variable.Instance */
.highlight .vm { color: #f8f8f2 } /* Name.Variable.Magic */
.highlight .il { color: #ae81ff } /* Literal.Number.Integer.Long */
}
@media (prefers-color-scheme: light) {
.highlight .hll { background-color: #ffffcc }
.highlight .c { color: #888888 } /* Comment */
.highlight .err { color: #a61717; background-color: #e3d2d2 } /* Error */
.highlight .k { color: #008800; font-weight: bold } /* Keyword */
.highlight .ch { color: #888888 } /* Comment.Hashbang */
.highlight .cm { color: #888888 } /* Comment.Multiline */
.highlight .cp { color: #cc0000; font-weight: bold } /* Comment.Preproc */
.highlight .cpf { color: #888888 } /* Comment.PreprocFile */
.highlight .c1 { color: #888888 } /* Comment.Single */
.highlight .cs { color: #cc0000; font-weight: bold; background-color: #fff0f0 } /* Comment.Special */
.highlight .gd { color: #000000; background-color: #ffdddd } /* Generic.Deleted */
.highlight .ge { font-style: italic } /* Generic.Emph */
.highlight .gr { color: #aa0000 } /* Generic.Error */
.highlight .gh { color: #333333 } /* Generic.Heading */
.highlight .gi { color: #000000; background-color: #ddffdd } /* Generic.Inserted */
.highlight .go { color: #888888 } /* Generic.Output */
.highlight .gp { color: #555555 } /* Generic.Prompt */
.highlight .gs { font-weight: bold } /* Generic.Strong */
.highlight .gu { color: #666666 } /* Generic.Subheading */
.highlight .gt { color: #aa0000 } /* Generic.Traceback */
.highlight .kc { color: #008800; font-weight: bold } /* Key