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// -*- Mode: Go; indent-tabs-mode: t -*-
/*
* Copyright (C) 2015-2019 Canonical Ltd
*
* This program is free software: you can redistribute it and/or modify
* it under the terms of the GNU General Public License version 3 as
* published by the Free Software Foundation.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with this program. If not, see <http://www.gnu.org/licenses/>.
*
*/
package netutil
import (
"fmt"
"net"
"os"
"runtime"
unix "syscall"
"github.com/coreos/go-systemd/activation"
"github.com/snapcore/snapd/logger"
)
// GetListener tries to get a listener for the given socket path from
// the listener map, and if it fails it tries to set it up directly.
func GetListener(socketPath string, listenerMap map[string]net.Listener) (net.Listener, error) {
if listener, ok := listenerMap[socketPath]; ok {
return listener, nil
}
if c, err := net.Dial("unix", socketPath); err == nil {
c.Close()
return nil, fmt.Errorf("socket %q already in use", socketPath)
}
if err := os.Remove(socketPath); err != nil && !os.IsNotExist(err) {
return nil, err
}
address, err := net.ResolveUnixAddr("unix", socketPath)
if err != nil {
return nil, err
}
runtime.LockOSThread()
oldmask := unix.Umask(0111)
listener, err := net.ListenUnix("unix", address)
unix.Umask(oldmask)
runtime.UnlockOSThread()
if err != nil {
return nil, err
}
logger.Debugf("socket %q was not activated; listening", socketPath)
return listener, nil
}
// ActivationListeners builds a map of addresses to listeners that were passed
// during systemd activation
func ActivationListeners() (lns map[string]net.Listener, err error) {
// pass false to keep LISTEN_* environment variables passed by systemd
files := activation.Files(false)
lns = make(map[string]net.Listener, len(files))
for _, f := range files {
ln, err := net.FileListener(f)
if err != nil {
return nil, err
}
addr := ln.Addr().String()
lns[addr] = ln
}
return lns, nil
}
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