forked from TrueCloudLab/distribution
90 lines
2.2 KiB
Go
90 lines
2.2 KiB
Go
package listener
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import (
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"fmt"
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"net"
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"os"
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"time"
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"github.com/coreos/go-systemd/v22/activation"
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log "github.com/sirupsen/logrus"
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)
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// tcpKeepAliveListener sets TCP keep-alive timeouts on accepted
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// connections. It's used by ListenAndServe and ListenAndServeTLS so
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// dead TCP connections (e.g. closing laptop mid-download) eventually
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// go away.
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// it is a plain copy-paste from net/http/server.go
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type tcpKeepAliveListener struct {
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*net.TCPListener
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}
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func (ln tcpKeepAliveListener) Accept() (c net.Conn, err error) {
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tc, err := ln.AcceptTCP()
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if err != nil {
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return
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}
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tc.SetKeepAlive(true)
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tc.SetKeepAlivePeriod(3 * time.Minute)
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return tc, nil
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}
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// NewListener announces on laddr and net. Accepted values of the net are
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// 'unix' and 'tcp'
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func NewListener(net, laddr string) (net.Listener, error) {
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listeners, err := activation.Listeners()
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if err != nil {
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return nil, fmt.Errorf("Socket activation failed: %v", err)
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}
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switch len(listeners) {
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case 0:
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// No socket-activation found
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switch net {
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case "unix":
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return newUnixListener(laddr)
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case "tcp", "": // an empty net means tcp
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return newTCPListener(laddr)
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default:
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return nil, fmt.Errorf("unknown address type %s", net)
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}
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case 1:
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log.Info("Socet-activation is being used. Overriding requested address")
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return listeners[0], nil
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default:
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return nil, fmt.Errorf("Found %d socket-activation listeners, only expected 1", len(listeners))
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}
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}
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func newUnixListener(laddr string) (net.Listener, error) {
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fi, err := os.Stat(laddr)
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if err == nil {
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// the file exists.
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// try to remove it if it's a socket
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if !isSocket(fi.Mode()) {
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return nil, fmt.Errorf("file %s exists and is not a socket", laddr)
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}
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if err := os.Remove(laddr); err != nil {
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return nil, err
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}
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} else if !os.IsNotExist(err) {
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// we can't do stat on the file.
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// it means we can not remove it
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return nil, err
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}
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return net.Listen("unix", laddr)
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}
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func isSocket(m os.FileMode) bool {
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return m&os.ModeSocket != 0
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}
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func newTCPListener(laddr string) (net.Listener, error) {
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ln, err := net.Listen("tcp", laddr)
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if err != nil {
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return nil, err
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}
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return tcpKeepAliveListener{ln.(*net.TCPListener)}, nil
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}
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