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// Copyright © 2016 Zlatko Čalušić
//
// Use of this source code is governed by an MIT-style license that can be found in the LICENSE file.
package sysinfo
import (
"bufio"
"crypto/rand"
"fmt"
"os"
"strings"
"time"
)
// Node information.
type Node struct {
Hostname string `json:"hostname,omitempty"`
MachineID string `json:"machineid,omitempty"`
Hypervisor string `json:"hypervisor,omitempty"`
Timezone string `json:"timezone,omitempty"`
}
func (si *SysInfo) getHostname() {
si.Node.Hostname = slurpFile("/proc/sys/kernel/hostname")
}
func (si *SysInfo) getSetMachineID() {
const pathSystemdMachineID = "/etc/machine-id"
const pathDbusMachineID = "/var/lib/dbus/machine-id"
systemdMachineID := slurpFile(pathSystemdMachineID)
dbusMachineID := slurpFile(pathDbusMachineID)
if systemdMachineID != "" && dbusMachineID != "" {
// All OK, just return the machine id.
if systemdMachineID == dbusMachineID {
si.Node.MachineID = systemdMachineID
return
}
// They both exist, but they don't match! Copy systemd machine id to DBUS machine id.
spewFile(pathDbusMachineID, systemdMachineID, 0444)
si.Node.MachineID = systemdMachineID
return
}
// Copy DBUS machine id to non-existent systemd machine id.
if systemdMachineID == "" && dbusMachineID != "" {
spewFile(pathSystemdMachineID, dbusMachineID, 0444)
si.Node.MachineID = dbusMachineID
return
}
// Copy systemd machine id to non-existent DBUS machine id.
if systemdMachineID != "" && dbusMachineID == "" {
spewFile(pathDbusMachineID, systemdMachineID, 0444)
si.Node.MachineID = systemdMachineID
return
}
// Generate and write fresh new machine ID to both locations, conforming to the DBUS specification:
// https://dbus.freedesktop.org/doc/dbus-specification.html#uuids
random := make([]byte, 12)
if _, err := rand.Read(random); err != nil {
return
}
newMachineID := fmt.Sprintf("%x%x", random, time.Now().Unix())
spewFile(pathSystemdMachineID, newMachineID, 0444)
spewFile(pathDbusMachineID, newMachineID, 0444)
si.Node.MachineID = newMachineID
}
func (si *SysInfo) getTimezone() {
const zoneInfoPrefix = "/usr/share/zoneinfo/"
if fi, err := os.Lstat("/etc/localtime"); err == nil {
if fi.Mode()&os.ModeSymlink == os.ModeSymlink {
if tzfile, err := os.Readlink("/etc/localtime"); err == nil {
tzfile = strings.TrimPrefix(tzfile, "..")
if strings.HasPrefix(tzfile, zoneInfoPrefix) {
si.Node.Timezone = strings.TrimPrefix(tzfile, zoneInfoPrefix)
return
} else if strings.HasPrefix(tzfile, "../usr/share/zoneinfo/") {
si.Node.Timezone = strings.TrimPrefix(tzfile, "../usr/share/zoneinfo/")
return
}
}
}
}
if timezone := slurpFile("/etc/timezone"); timezone != "" {
si.Node.Timezone = timezone
return
}
if f, err := os.Open("/etc/sysconfig/clock"); err == nil {
defer f.Close()
s := bufio.NewScanner(f)
for s.Scan() {
if sl := strings.Split(s.Text(), "="); len(sl) == 2 {
if sl[0] == "ZONE" {
si.Node.Timezone = strings.Trim(sl[1], `"`)
return
}
}
}
}
}
func (si *SysInfo) getNodeInfo() {
si.getHostname()
si.getSetMachineID()
si.getHypervisor()
si.getTimezone()
}
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