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  }