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https://github.com/tailscale/tailscale.git
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51 lines
1.4 KiB
Go
51 lines
1.4 KiB
Go
// Copyright (c) 2020 Tailscale Inc & AUTHORS All rights reserved.
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// Use of this source code is governed by a BSD-style
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// license that can be found in the LICENSE file.
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// +build !windows
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package safesocket
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import (
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"fmt"
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"net"
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"os"
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"path/filepath"
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)
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// TODO(apenwarr): handle magic cookie auth
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func connect(path string, port uint16) (net.Conn, error) {
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pipe, err := net.Dial("unix", path)
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if err != nil {
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return nil, err
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}
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return pipe, err
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}
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// TODO(apenwarr): handle magic cookie auth
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func listen(path string, port uint16) (ln net.Listener, _ uint16, err error) {
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// Unix sockets hang around in the filesystem even after nobody
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// is listening on them. (Which is really unfortunate but long-
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// entrenched semantics.) Try connecting first; if it works, then
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// the socket is still live, so let's not replace it. If it doesn't
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// work, then replace it.
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//
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// Note that there's a race condition between these two steps. A
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// "proper" daemon usually uses a dance involving pidfiles to first
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// ensure that no other instances of itself are running, but that's
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// beyond the scope of our simple socket library.
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c, err := net.Dial("unix", path)
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if err == nil {
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c.Close()
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return nil, 0, fmt.Errorf("%v: address already in use", path)
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}
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_ = os.Remove(path)
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os.MkdirAll(filepath.Dir(path), 0755) // best effort
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pipe, err := net.Listen("unix", path)
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if err != nil {
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return nil, 0, err
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}
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os.Chmod(path, 0666)
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return pipe, 0, err
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}
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