// Copyright 2009 The Go 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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package os
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import (
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"runtime"
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"syscall"
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)
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func hostname() (name string, err error) {
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// Try uname first, as it's only one system call and reading
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// from /proc is not allowed on Android.
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var un syscall.Utsname
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err = syscall.Uname(&un)
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var buf [512]byte // Enough for a DNS name.
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for i, b := range un.Nodename[:] {
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buf[i] = uint8(b)
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if b == 0 {
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name = string(buf[:i])
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break
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}
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}
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// If we got a name and it's not potentially truncated
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// (Nodename is 65 bytes), return it.
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if err == nil && len(name) > 0 && len(name) < 64 {
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return name, nil
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}
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if runtime.GOOS == "android" {
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if name != "" {
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return name, nil
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}
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return "localhost", nil
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}
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f, err := Open("/proc/sys/kernel/hostname")
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if err != nil {
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return "", err
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}
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defer f.Close()
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n, err := f.Read(buf[:])
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if err != nil {
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return "", err
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}
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if n > 0 && buf[n-1] == '\n' {
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n--
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}
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return string(buf[:n]), nil
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}
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