io-multiplex/epoll.lisp

   1 ;;;; -*- Mode: Lisp; Syntax: ANSI-Common-Lisp; Indent-tabs-mode: NIL -*-
   2 ;;;
   3 ;;; epoll.lisp --- epoll()-based multiplexer implementation.
   4 ;;;
   5 ;;; Copyright (C) 2006-2007, Stelian Ionescu  <sionescu@common-lisp.net>
   6 ;;;
   7 ;;; This code is free software; you can redistribute it and/or
   8 ;;; modify it under the terms of the version 2.1 of
   9 ;;; the GNU Lesser General Public License as published by
  10 ;;; the Free Software Foundation, as clarified by the
  11 ;;; preamble found here:
  12 ;;;     http://opensource.franz.com/preamble.html
  13 ;;;
  14 ;;; This program is distributed in the hope that it will be useful,
  15 ;;; but WITHOUT ANY WARRANTY; without even the implied warranty of
  16 ;;; MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  17 ;;; GNU General Public License for more details.
  18 ;;;
  19 ;;; You should have received a copy of the GNU Lesser General
  20 ;;; Public License along with this library; if not, write to the
  21 ;;; Free Software Foundation, Inc., 51 Franklin St, Fifth Floor,
  22 ;;; Boston, MA 02110-1301, USA
  23
  24 (in-package :io.multiplex)
  25
  26 (defconstant +epoll-priority+ 1)
  27
  28 (define-multiplexer epoll-multiplexer +epoll-priority+ (multiplexer)
  29   ())
  30
  31 (defmethod print-object ((mux epoll-multiplexer) stream)
  32   (print-unreadable-object (mux stream :type nil :identity nil)
  33     (format stream "epoll(4) multiplexer")))
  34
  35 (defconstant +epoll-default-size-hint+ 25)
  36 (defvar *epoll-max-events* 200)
  37
  38 (defmethod initialize-instance :after ((mux epoll-multiplexer)
  39                                        &key (size +epoll-default-size-hint+))
  40   (setf (slot-value mux 'fd) (nix:epoll-create size)))
  41
  42 (defun calc-epoll-flags (fd-entry)
  43   (logior (if (fd-entry-read-event fd-entry)
  44               nix::epollin 0)
  45           (if (fd-entry-write-event fd-entry)
  46               nix::epollout 0)
  47           nix::epollpri))
  48
  49 (defmethod monitor-fd ((mux epoll-multiplexer) fd-entry)
  50   (assert fd-entry)
  51   (let ((flags (calc-epoll-flags fd-entry))
  52         (fd (fd-entry-fd fd-entry)))
  53     (with-foreign-object (ev 'nix::epoll-event)
  54       (nix:bzero ev nix::size-of-epoll-event)
  55       (setf (foreign-slot-value ev 'nix::epoll-event 'nix::events)
  56             flags)
  57       (setf (foreign-slot-value
  58              (foreign-slot-value ev 'nix::epoll-event 'nix::data)
  59              'nix::epoll-data 'nix::fd)
  60             fd)
  61       (handler-case
  62           (nix:epoll-ctl (fd-of mux) nix:epoll-ctl-add fd ev)
  63         (nix:ebadf ()
  64           (warn "FD ~A is invalid, cannot monitor it." fd))
  65         (nix:eexist ()
  66           (warn "FD ~A is already monitored." fd))))))
  67
  68 (defmethod update-fd ((mux epoll-multiplexer) fd-entry event-type edge-change)
  69   (declare (ignore event-type edge-change))
  70   (assert fd-entry)
  71   (let ((flags (calc-epoll-flags fd-entry))
  72         (fd (fd-entry-fd fd-entry)))
  73     (with-foreign-object (ev 'nix::epoll-event)
  74       (nix:bzero ev nix::size-of-epoll-event)
  75       (setf (foreign-slot-value ev 'nix::epoll-event 'nix::events)
  76             flags)
  77       (setf (foreign-slot-value
  78              (foreign-slot-value ev 'nix::epoll-event 'nix::data)
  79              'nix::epoll-data 'nix::fd)
  80             fd)
  81       (handler-case
  82           (nix:epoll-ctl (fd-of mux) nix::epoll-ctl-mod fd ev)
  83         (nix:ebadf ()
  84           (warn "FD ~A is invalid, cannot update its status." fd))
  85         (nix:enoent ()
  86           (warn "FD ~A was not monitored, cannot update its status." fd))))
  87     (values fd-entry)))
  88
  89 (defmethod unmonitor-fd ((mux epoll-multiplexer) fd-entry)
  90   (handler-case
  91       (nix:epoll-ctl (fd-of mux)
  92                      nix::epoll-ctl-del
  93                      (fd-entry-fd fd-entry)
  94                      (null-pointer))
  95     (nix:ebadf ()
  96       (warn "FD ~A is invalid, cannot unmonitor it." (fd-entry-fd fd-entry)))
  97     (nix:enoent ()
  98       (warn "FD ~A was not monitored, cannot unmonitor it."
  99             (fd-entry-fd fd-entry)))))
 100
 101 (defmethod harvest-events ((mux epoll-multiplexer) timeout)
 102   (with-foreign-object (events 'nix::epoll-event *epoll-max-events*)
 103     (nix:bzero events (* *epoll-max-events* nix::size-of-epoll-event))
 104     (let (ready-fds)
 105       (nix:repeat-upon-condition-decreasing-timeout
 106           ((nix:eintr) tmp-timeout timeout)
 107         (setf ready-fds (nix:epoll-wait (fd-of mux) events *epoll-max-events*
 108                                         (timeout->milisec tmp-timeout))))
 109       (macrolet ((epoll-slot (slot-name)
 110                    `(foreign-slot-value (mem-aref events 'nix::epoll-event i)
 111                                         'nix::epoll-event ',slot-name)))
 112         (return-from harvest-events
 113           (loop :for i :below ready-fds
 114                 :for fd := (foreign-slot-value (epoll-slot nix::data)
 115                                                'nix::epoll-data 'nix::fd)
 116                 :for event-mask := (epoll-slot nix::events)
 117                 :for epoll-event := (make-epoll-event fd event-mask)
 118                 :when epoll-event :collect epoll-event))))))
 119
 120 (defun make-epoll-event (fd mask)
 121   (let ((event ()))
 122     (flags-case mask
 123       ((nix::epollout nix::epollhup)
 124        (push :write event))
 125       ((nix::epollin nix::epollpri nix::epollhup)
 126        (push :read event))
 127       (nix::epollerr
 128        (push :error event)))
 129     (when event
 130       (list fd event))))