124 lines
2.8 KiB
Go
124 lines
2.8 KiB
Go
// Copyright 2009 The Go Authors. All rights reserved.
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// Use of this source code is governed by a BSD-style
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// license that can be found in the LICENSE file.
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// +build freebsd netbsd openbsd
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// Waiting for FDs via kqueue/kevent.
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package net
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import (
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"os"
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"syscall"
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)
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type pollster struct {
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kq int
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eventbuf [10]syscall.Kevent_t
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events []syscall.Kevent_t
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// An event buffer for AddFD/DelFD.
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// Must hold pollServer lock.
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kbuf [1]syscall.Kevent_t
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}
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func newpollster() (p *pollster, err error) {
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p = new(pollster)
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if p.kq, err = syscall.Kqueue(); err != nil {
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return nil, os.NewSyscallError("kqueue", err)
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}
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syscall.CloseOnExec(p.kq)
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p.events = p.eventbuf[0:0]
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return p, nil
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}
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// First return value is whether the pollServer should be woken up.
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// This version always returns false.
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func (p *pollster) AddFD(fd int, mode int, repeat bool) (bool, error) {
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// pollServer is locked.
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var kmode int
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if mode == 'r' {
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kmode = syscall.EVFILT_READ
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} else {
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kmode = syscall.EVFILT_WRITE
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}
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ev := &p.kbuf[0]
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// EV_ADD - add event to kqueue list
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// EV_ONESHOT - delete the event the first time it triggers
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flags := syscall.EV_ADD
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if !repeat {
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flags |= syscall.EV_ONESHOT
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}
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syscall.SetKevent(ev, fd, kmode, flags)
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n, err := syscall.Kevent(p.kq, p.kbuf[:], nil, nil)
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if err != nil {
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return false, os.NewSyscallError("kevent", err)
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}
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if n != 1 || (ev.Flags&syscall.EV_ERROR) == 0 || int(ev.Ident) != fd || int(ev.Filter) != kmode {
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return false, os.NewSyscallError("kqueue phase error", err)
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}
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if ev.Data != 0 {
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return false, syscall.Errno(int(ev.Data))
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}
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return false, nil
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}
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// Return value is whether the pollServer should be woken up.
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// This version always returns false.
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func (p *pollster) DelFD(fd int, mode int) bool {
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// pollServer is locked.
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var kmode int
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if mode == 'r' {
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kmode = syscall.EVFILT_READ
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} else {
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kmode = syscall.EVFILT_WRITE
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}
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ev := &p.kbuf[0]
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// EV_DELETE - delete event from kqueue list
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syscall.SetKevent(ev, fd, kmode, syscall.EV_DELETE)
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syscall.Kevent(p.kq, p.kbuf[:], nil, nil)
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return false
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}
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func (p *pollster) WaitFD(s *pollServer, nsec int64) (fd int, mode int, err error) {
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var t *syscall.Timespec
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for len(p.events) == 0 {
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if nsec > 0 {
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if t == nil {
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t = new(syscall.Timespec)
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}
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*t = syscall.NsecToTimespec(nsec)
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}
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s.Unlock()
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n, err := syscall.Kevent(p.kq, nil, p.eventbuf[:], t)
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s.Lock()
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if err != nil {
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if err == syscall.EINTR {
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continue
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}
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return -1, 0, os.NewSyscallError("kevent", err)
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}
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if n == 0 {
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return -1, 0, nil
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}
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p.events = p.eventbuf[:n]
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}
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ev := &p.events[0]
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p.events = p.events[1:]
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fd = int(ev.Ident)
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if ev.Filter == syscall.EVFILT_READ {
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mode = 'r'
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} else {
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mode = 'w'
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}
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return fd, mode, nil
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}
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func (p *pollster) Close() error { return os.NewSyscallError("close", syscall.Close(p.kq)) }
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