/
utils.go
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/
utils.go
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// Copyright 2016-2020 Authors of Cilium
//
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
//
// http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.
package common
import (
"bufio"
"fmt"
"io"
"io/ioutil"
"os"
"path/filepath"
"strconv"
"strings"
"github.com/sirupsen/logrus"
)
// C2GoArray transforms an hexadecimal string representation into a byte slice.
// Example:
// str := "0x12, 0xff, 0x0, 0x1"
// fmt.Print(C2GoArray(str)) //`{0x12, 0xFF, 0x0, 0x01}`"
func C2GoArray(str string) []byte {
ret := []byte{}
if str == "" {
return ret
}
hexStr := strings.Split(str, ", ")
for _, hexDigit := range hexStr {
strDigit := strings.TrimPrefix(hexDigit, "0x")
digit, err := strconv.ParseInt(strDigit, 16, 9)
if err != nil {
return nil
}
ret = append(ret, byte(digit))
}
return ret
}
// GetCiliumVersionString returns the first line containing CiliumCHeaderPrefix.
func GetCiliumVersionString(epCHeaderFilePath string) (string, error) {
f, err := os.Open(epCHeaderFilePath)
if err != nil {
return "", err
}
br := bufio.NewReader(f)
defer f.Close()
for {
s, err := br.ReadString('\n')
if err == io.EOF {
return "", nil
}
if err != nil {
return "", err
}
if strings.Contains(s, CiliumCHeaderPrefix) {
return s, nil
}
}
}
// RequireRootPrivilege checks if the user running cmd is root. If not, it exits the program
func RequireRootPrivilege(cmd string) {
if os.Getuid() != 0 {
fmt.Fprintf(os.Stderr, "Please run %q command(s) with root privileges.\n", cmd)
os.Exit(1)
}
}
// MoveNewFilesTo copies all files, that do not exist in newDir, from oldDir.
func MoveNewFilesTo(oldDir, newDir string) error {
oldFiles, err := ioutil.ReadDir(oldDir)
if err != nil {
return err
}
newFiles, err := ioutil.ReadDir(newDir)
if err != nil {
return err
}
for _, oldFile := range oldFiles {
exists := false
for _, newFile := range newFiles {
if oldFile.Name() == newFile.Name() {
exists = true
break
}
}
if !exists {
os.Rename(filepath.Join(oldDir, oldFile.Name()), filepath.Join(newDir, oldFile.Name()))
}
}
return nil
}
// MapStringStructToSlice returns a slice with all keys of the given
// map[string]struct{}
func MapStringStructToSlice(m map[string]struct{}) []string {
s := make([]string, 0, len(m))
for k := range m {
s = append(s, k)
}
return s
}
// GetNumPossibleCPUs returns a total number of possible CPUS, i.e. CPUs that
// have been allocated resources and can be brought online if they are present.
// The number is retrieved by parsing /sys/device/system/cpu/possible.
//
// See https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/tree/include/linux/cpumask.h?h=v4.19#n50
// for more details.
func GetNumPossibleCPUs(log *logrus.Entry) int {
f, err := os.Open(PossibleCPUSysfsPath)
if err != nil {
log.WithError(err).Errorf("unable to open %q", PossibleCPUSysfsPath)
return 0
}
defer f.Close()
return getNumPossibleCPUsFromReader(log, f)
}
func getNumPossibleCPUsFromReader(log *logrus.Entry, r io.Reader) int {
out, err := ioutil.ReadAll(r)
if err != nil {
log.WithError(err).Errorf("unable to read %q to get CPU count", PossibleCPUSysfsPath)
return 0
}
var start, end int
count := 0
for _, s := range strings.Split(string(out), ",") {
// Go's scanf will return an error if a format cannot be fully matched.
// So, just ignore it, as a partial match (e.g. when there is only one
// CPU) is expected.
n, err := fmt.Sscanf(s, "%d-%d", &start, &end)
switch n {
case 0:
log.WithError(err).Errorf("failed to scan %q to retrieve number of possible CPUs!", s)
return 0
case 1:
count++
default:
count += (end - start + 1)
}
}
return count
}