1 // Copyright 2009 The Go Authors. All rights reserved.
2 // Use of this source code is governed by a BSD-style
3 // license that can be found in the LICENSE file.
5 // Waiting for FDs via epoll(7).
15 readFlags = syscall.EPOLLIN | syscall.EPOLLRDHUP
16 writeFlags = syscall.EPOLLOUT
19 type pollster struct {
22 // Events we're already waiting for
26 func newpollster() (p *pollster, err os.Error) {
30 // The arg to epoll_create is a hint to the kernel
31 // about the number of FDs we will care about.
33 if p.epfd, e = syscall.EpollCreate(16); e != 0 {
34 return nil, os.NewSyscallError("epoll_create", e)
36 p.events = make(map[int]uint32)
40 func (p *pollster) AddFD(fd int, mode int, repeat bool) os.Error {
41 var ev syscall.EpollEvent
44 ev.Events, already = p.events[fd]
46 ev.Events |= syscall.EPOLLONESHOT
49 ev.Events |= readFlags
51 ev.Events |= writeFlags
56 op = syscall.EPOLL_CTL_MOD
58 op = syscall.EPOLL_CTL_ADD
60 if e := syscall.EpollCtl(p.epfd, op, fd, &ev); e != 0 {
61 return os.NewSyscallError("epoll_ctl", e)
63 p.events[fd] = ev.Events
67 func (p *pollster) StopWaiting(fd int, bits uint) {
68 events, already := p.events[fd]
70 print("Epoll unexpected fd=", fd, "\n")
74 // If syscall.EPOLLONESHOT is not set, the wait
75 // is a repeating wait, so don't change it.
76 if events&syscall.EPOLLONESHOT == 0 {
80 // Disable the given bits.
81 // If we're still waiting for other events, modify the fd
82 // event in the kernel. Otherwise, delete it.
83 events &= ^uint32(bits)
84 if int32(events)&^syscall.EPOLLONESHOT != 0 {
85 var ev syscall.EpollEvent
88 if e := syscall.EpollCtl(p.epfd, syscall.EPOLL_CTL_MOD, fd, &ev); e != 0 {
89 print("Epoll modify fd=", fd, ": ", os.Errno(e).String(), "\n")
93 if e := syscall.EpollCtl(p.epfd, syscall.EPOLL_CTL_DEL, fd, nil); e != 0 {
94 print("Epoll delete fd=", fd, ": ", os.Errno(e).String(), "\n")
96 p.events[fd] = 0, false
100 func (p *pollster) DelFD(fd int, mode int) {
102 p.StopWaiting(fd, readFlags)
104 p.StopWaiting(fd, writeFlags)
108 func (p *pollster) WaitFD(nsec int64) (fd int, mode int, err os.Error) {
110 var evarray [1]syscall.EpollEvent
114 msec = int((nsec + 1e6 - 1) / 1e6)
116 n, e := syscall.EpollWait(p.epfd, evarray[0:], msec)
117 for e == syscall.EAGAIN || e == syscall.EINTR {
118 n, e = syscall.EpollWait(p.epfd, evarray[0:], msec)
121 return -1, 0, os.NewSyscallError("epoll_wait", e)
128 if ev.Events&writeFlags != 0 {
129 p.StopWaiting(fd, writeFlags)
132 if ev.Events&readFlags != 0 {
133 p.StopWaiting(fd, readFlags)
137 // Other events are error conditions - wake whoever is waiting.
138 events, _ := p.events[fd]
139 if events&writeFlags != 0 {
140 p.StopWaiting(fd, writeFlags)
143 p.StopWaiting(fd, readFlags)
147 func (p *pollster) Close() os.Error {
148 return os.NewSyscallError("close", syscall.Close(p.epfd))