Files
node-problem-detector/pkg/util/metrics/system/cmdline_args.go
2025-09-11 18:47:20 +00:00

93 lines
2.6 KiB
Go

/*
Copyright 2020 The Kubernetes Authors All rights reserved.
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 system
import (
"encoding/json"
"fmt"
"strings"
"k8s.io/klog/v2"
)
type CmdlineArg struct {
Key string `json:"key"`
Value string `json:"value"`
}
func (d CmdlineArg) String() string {
s, err := json.Marshal(d)
if err != nil {
klog.Errorf("failed to marshal cmdline arg: %v", err)
return ""
}
return string(s)
}
// As per the documentation kernel command line parameters can also be specified
// within double quotes and are separated with spaces.
// https://www.kernel.org/doc/html/v4.14/admin-guide/kernel-parameters.html#the-kernel-s-command-line-parameters
var withinQuotes = false
func splitAfterSpace(inputChar rune) bool {
// words with space within double quotes cannot be split.
// so we track the start quote and when we find the
// end quote, then we reiterate.
if inputChar == '"' {
withinQuotes = !withinQuotes
return false
}
// ignore spaces when it is within quotes.
if withinQuotes {
return false
}
return inputChar == ' '
}
// CmdlineArgs returns all the kernel cmdline. It is read from cat /proc/cmdline.
func CmdlineArgs(cmdlineFilePath string) ([]CmdlineArg, error) {
lines, err := ReadFileIntoLines(cmdlineFilePath)
if err != nil {
return nil, fmt.Errorf("error reading the file %s, %v", cmdlineFilePath, err)
}
if len(lines) < 1 {
return nil, fmt.Errorf("no lines are returned")
}
cmdlineArgs := strings.FieldsFunc(lines[0], splitAfterSpace)
result := make([]CmdlineArg, 0, len(cmdlineArgs))
// for commandline only one line is returned.
for _, words := range cmdlineArgs {
// Ignore the keys that start with double quotes
if strings.Index(words, "\"") == 0 {
continue
}
tokens := strings.Split(words, "=")
if len(tokens) < 2 {
stats := CmdlineArg{
Key: tokens[0],
}
result = append(result, stats)
} else {
// remove quotes in the values
trimmedValue := strings.Trim(tokens[1], "\"'")
stats := CmdlineArg{
Key: tokens[0],
Value: trimmedValue,
}
result = append(result, stats)
}
}
return result, nil
}