Source file src/os/sys_linux.go

     1	// Copyright 2009 The Go Authors. All rights reserved.
     2	// Use of this source code is governed by a BSD-style
     3	// license that can be found in the LICENSE file.
     4	
     5	package os
     6	
     7	import (
     8		"runtime"
     9		"syscall"
    10	)
    11	
    12	func hostname() (name string, err error) {
    13		// Try uname first, as it's only one system call and reading
    14		// from /proc is not allowed on Android.
    15		var un syscall.Utsname
    16		err = syscall.Uname(&un)
    17	
    18		var buf [512]byte // Enough for a DNS name.
    19		for i, b := range un.Nodename[:] {
    20			buf[i] = uint8(b)
    21			if b == 0 {
    22				name = string(buf[:i])
    23				break
    24			}
    25		}
    26		// If we got a name and it's not potentially truncated
    27		// (Nodename is 65 bytes), return it.
    28		if err == nil && len(name) > 0 && len(name) < 64 {
    29			return name, nil
    30		}
    31		if runtime.GOOS == "android" {
    32			if name != "" {
    33				return name, nil
    34			}
    35			return "localhost", nil
    36		}
    37	
    38		f, err := Open("/proc/sys/kernel/hostname")
    39		if err != nil {
    40			return "", err
    41		}
    42		defer f.Close()
    43	
    44		n, err := f.Read(buf[:])
    45		if err != nil {
    46			return "", err
    47		}
    48	
    49		if n > 0 && buf[n-1] == '\n' {
    50			n--
    51		}
    52		return string(buf[:n]), nil
    53	}
    54	

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