1 files changed, 150 insertions, 0 deletions
diff --git a/src/pkg/net/fd_linux.go b/src/pkg/net/fd_linux.go
new file mode 100644
index 000000000..bd822589e
--- /dev/null
+++ b/src/pkg/net/fd_linux.go
@@ -0,0 +1,150 @@
+// Copyright 2009 The Go Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+// Waiting for FDs via epoll(7).
+
+package net
+
+import (
+	"net";
+	"os";
+	"syscall";
+)
+
+const (
+	readFlags = syscall.EPOLLIN | syscall.EPOLLRDHUP;
+	writeFlags = syscall.EPOLLOUT
+)
+
+type pollster struct {
+	epfd int;
+
+	// Events we're already waiting for
+	events map[int] uint32;
+}
+
+func newpollster() (p *pollster, err os.Error) {
+	p = new(pollster);
+	var e int;
+
+	// The arg to epoll_create is a hint to the kernel
+	// about the number of FDs we will care about.
+	// We don't know.
+	if p.epfd, e = syscall.EpollCreate(16); e != 0 {
+		return nil, os.ErrnoToError(e)
+	}
+	p.events = make(map[int] uint32);
+	return p, nil
+}
+
+func (p *pollster) AddFD(fd int, mode int, repeat bool) os.Error {
+	var ev syscall.EpollEvent;
+	var already bool;
+	ev.Fd = int32(fd);
+	ev.Events, already = p.events[fd];
+	if !repeat {
+		ev.Events |= syscall.EPOLLONESHOT;
+	}
+	if mode == 'r' {
+		ev.Events |= readFlags;
+	} else {
+		ev.Events |= writeFlags;
+	}
+
+	var op int;
+	if already {
+		op = syscall.EPOLL_CTL_MOD;
+	} else {
+		op = syscall.EPOLL_CTL_ADD;
+	}
+	if e := syscall.EpollCtl(p.epfd, op, fd, &ev); e != 0 {
+		return os.ErrnoToError(e)
+	}
+	p.events[fd] = ev.Events;
+	return nil
+}
+
+func (p *pollster) StopWaiting(fd int, bits uint) {
+	events, already := p.events[fd];
+	if !already {
+		print("Epoll unexpected fd=", fd, "\n");
+		return;
+	}
+
+	// If syscall.EPOLLONESHOT is not set, the wait
+	// is a repeating wait, so don't change it.
+	if events & syscall.EPOLLONESHOT == 0 {
+		return;
+	}
+
+	// Disable the given bits.
+	// If we're still waiting for other events, modify the fd
+	// event in the kernel.  Otherwise, delete it.
+	events &= ^uint32(bits);
+	if int32(events) & ^syscall.EPOLLONESHOT != 0 {
+		var ev syscall.EpollEvent;
+		ev.Fd = int32(fd);
+		ev.Events = events;
+		if e := syscall.EpollCtl(p.epfd, syscall.EPOLL_CTL_MOD, fd, &ev); e != 0 {
+			print("Epoll modify fd=", fd, ": ", os.ErrnoToError(e).String(), "\n");
+		}
+		p.events[fd] = events;
+	} else {
+		if e := syscall.EpollCtl(p.epfd, syscall.EPOLL_CTL_DEL, fd, nil); e != 0 {
+			print("Epoll delete fd=", fd, ": ", os.ErrnoToError(e).String(), "\n");
+		}
+		p.events[fd] = 0, false;
+	}
+}
+
+func (p *pollster) DelFD(fd int, mode int) {
+	if mode == 'r' {
+		p.StopWaiting(fd, readFlags);
+	} else {
+		p.StopWaiting(fd, writeFlags);
+	}
+}
+
+func (p *pollster) WaitFD(nsec int64) (fd int, mode int, err os.Error) {
+	// Get an event.
+	var evarray [1]syscall.EpollEvent;
+	ev := &evarray[0];
+	var msec int = -1;
+	if nsec > 0 {
+		msec = int((nsec + 1e6 - 1)/1e6);
+	}
+	n, e := syscall.EpollWait(p.epfd, &evarray, msec);
+	for e == syscall.EAGAIN || e == syscall.EINTR {
+		n, e = syscall.EpollWait(p.epfd, &evarray, msec);
+	}
+	if e != 0 {
+		return -1, 0, os.ErrnoToError(e);
+	}
+	if n == 0 {
+		return -1, 0, nil;
+	}
+	fd = int(ev.Fd);
+
+	if ev.Events & writeFlags != 0 {
+		p.StopWaiting(fd, writeFlags);
+		return fd, 'w', nil;
+	}
+	if ev.Events & readFlags != 0 {
+		p.StopWaiting(fd, readFlags);
+		return fd, 'r', nil;
+	}
+
+	// Other events are error conditions - wake whoever is waiting.
+	events, already := p.events[fd];
+	if events & writeFlags != 0 {
+		p.StopWaiting(fd, writeFlags);
+		return fd, 'w', nil;
+	}
+	p.StopWaiting(fd, readFlags);
+	return fd, 'r', nil;
+}
+
+func (p *pollster) Close() os.Error {
+	return os.ErrnoToError(syscall.Close(p.epfd));
+}