tailscale/control/controlclient/hostinfo_linux.go

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// Copyright (c) 2020 Tailscale Inc & AUTHORS All rights reserved.
// Use of this source code is governed by a BSD-style
// license that can be found in the LICENSE file.
// +build linux,!android
package controlclient
import (
"bytes"
"fmt"
"io"
"io/ioutil"
"strings"
"syscall"
"go4.org/mem"
"tailscale.com/util/lineread"
"tailscale.com/version/distro"
)
func init() {
osVersion = osVersionLinux
}
func osVersionLinux() string {
dist := distro.Get()
propFile := "/etc/os-release"
if dist == distro.Synology {
propFile = "/etc.defaults/VERSION"
}
m := map[string]string{}
lineread.File(propFile, func(line []byte) error {
eq := bytes.IndexByte(line, '=')
if eq == -1 {
return nil
}
k, v := string(line[:eq]), strings.Trim(string(line[eq+1:]), `"`)
m[k] = v
return nil
})
var un syscall.Utsname
syscall.Uname(&un)
var attrBuf strings.Builder
attrBuf.WriteString("; kernel=")
for _, b := range un.Release {
if b == 0 {
break
}
attrBuf.WriteByte(byte(b))
}
if inContainer() {
attrBuf.WriteString("; container")
}
attr := attrBuf.String()
id := m["ID"]
switch id {
case "debian":
slurp, _ := ioutil.ReadFile("/etc/debian_version")
return fmt.Sprintf("Debian %s (%s)%s", bytes.TrimSpace(slurp), m["VERSION_CODENAME"], attr)
case "ubuntu":
return fmt.Sprintf("Ubuntu %s%s", m["VERSION"], attr)
case "", "centos": // CentOS 6 has no /etc/os-release, so its id is ""
if cr, _ := ioutil.ReadFile("/etc/centos-release"); len(cr) > 0 { // "CentOS release 6.10 (Final)
return fmt.Sprintf("%s%s", bytes.TrimSpace(cr), attr)
}
fallthrough
case "fedora", "rhel", "alpine":
// Their PRETTY_NAME is fine as-is for all versions I tested.
fallthrough
default:
if v := m["PRETTY_NAME"]; v != "" {
return fmt.Sprintf("%s%s", v, attr)
}
}
if dist == distro.Synology {
return fmt.Sprintf("Synology %s%s", m["productversion"], attr)
}
return fmt.Sprintf("Other%s", attr)
}
func inContainer() (ret bool) {
lineread.File("/proc/1/cgroup", func(line []byte) error {
if mem.Contains(mem.B(line), mem.S("/docker/")) ||
mem.Contains(mem.B(line), mem.S("/lxc/")) {
ret = true
return io.EOF // arbitrary non-nil error to stop loop
}
return nil
})
return
}