github.com/looshlee/cilium@v1.6.12/pkg/sysctl/sysctl.go (about) 1 // Copyright 2019 Authors of Cilium 2 // 3 // Licensed under the Apache License, Version 2.0 (the "License"); 4 // you may not use this file except in compliance with the License. 5 // You may obtain a copy of the License at 6 // 7 // http://www.apache.org/licenses/LICENSE-2.0 8 // 9 // Unless required by applicable law or agreed to in writing, software 10 // distributed under the License is distributed on an "AS IS" BASIS, 11 // WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. 12 // See the License for the specific language governing permissions and 13 // limitations under the License. 14 15 package sysctl 16 17 import ( 18 "fmt" 19 "io" 20 "os" 21 "path/filepath" 22 "strings" 23 ) 24 25 const ( 26 prefixDir = "/proc/sys" 27 ) 28 29 func fullPath(name string) string { 30 return filepath.Join(prefixDir, strings.Replace(name, ".", "/", -1)) 31 } 32 33 func writeSysctl(name string, value string) error { 34 fPath := fullPath(name) 35 f, err := os.OpenFile(fPath, os.O_RDWR, 0644) 36 if err != nil { 37 return fmt.Errorf("could not open the sysctl file %s: %s", 38 fPath, err) 39 } 40 defer f.Close() 41 if _, err := io.WriteString(f, value); err != nil { 42 return fmt.Errorf("could not write to the systctl file %s: %s", 43 fPath, err) 44 } 45 return nil 46 } 47 48 // Disable disables the given sysctl parameter. 49 func Disable(name string) error { 50 return writeSysctl(name, "0") 51 } 52 53 // Enable enables the given sysctl parameter. 54 func Enable(name string) error { 55 return writeSysctl(name, "1") 56 } 57 58 // Write writes the given sysctl parameter. 59 func Write(name string, val string) error { 60 return writeSysctl(name, val) 61 }