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go/src/net/fd_poll_nacl.go
Ian Lance Taylor 873dca4c17 net: use runtime.Keepalive for *netFD values
The net package sets a finalizer on *netFD. I looked through all the
uses of *netFD in the package, looking for each case where a *netFD
was passed as an argument and the final reference to the argument was
not a function or method call. I added a call to runtime.KeepAlive after
each such final reference (there were only three).

The code is safe today without the KeepAlive calls because the compiler
keeps arguments alive for the duration of the function. However, that is
not a language requirement, so adding the KeepAlive calls ensures that
this code remains safe even if the compiler changes in the future.

Change-Id: I4e2bd7c5a946035dc509ccefb4828f72335a9ee3
Reviewed-on: https://go-review.googlesource.com/27650
Run-TryBot: Ian Lance Taylor <iant@golang.org>
Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
2016-08-24 16:57:50 +00:00

90 lines
1.7 KiB
Go

// Copyright 2013 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.
package net
import (
"runtime"
"syscall"
"time"
)
type pollDesc struct {
fd *netFD
closing bool
}
func (pd *pollDesc) init(fd *netFD) error { pd.fd = fd; return nil }
func (pd *pollDesc) close() {}
func (pd *pollDesc) evict() {
pd.closing = true
if pd.fd != nil {
syscall.StopIO(pd.fd.sysfd)
runtime.KeepAlive(pd.fd)
}
}
func (pd *pollDesc) prepare(mode int) error {
if pd.closing {
return errClosing
}
return nil
}
func (pd *pollDesc) prepareRead() error { return pd.prepare('r') }
func (pd *pollDesc) prepareWrite() error { return pd.prepare('w') }
func (pd *pollDesc) wait(mode int) error {
if pd.closing {
return errClosing
}
return errTimeout
}
func (pd *pollDesc) waitRead() error { return pd.wait('r') }
func (pd *pollDesc) waitWrite() error { return pd.wait('w') }
func (pd *pollDesc) waitCanceled(mode int) {}
func (pd *pollDesc) waitCanceledRead() {}
func (pd *pollDesc) waitCanceledWrite() {}
func (fd *netFD) setDeadline(t time.Time) error {
return setDeadlineImpl(fd, t, 'r'+'w')
}
func (fd *netFD) setReadDeadline(t time.Time) error {
return setDeadlineImpl(fd, t, 'r')
}
func (fd *netFD) setWriteDeadline(t time.Time) error {
return setDeadlineImpl(fd, t, 'w')
}
func setDeadlineImpl(fd *netFD, t time.Time, mode int) error {
d := t.UnixNano()
if t.IsZero() {
d = 0
}
if err := fd.incref(); err != nil {
return err
}
switch mode {
case 'r':
syscall.SetReadDeadline(fd.sysfd, d)
case 'w':
syscall.SetWriteDeadline(fd.sysfd, d)
case 'r' + 'w':
syscall.SetReadDeadline(fd.sysfd, d)
syscall.SetWriteDeadline(fd.sysfd, d)
}
fd.decref()
return nil
}