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node-feature-discovery/source/kernel/kernel.go
Markus Lehtonen eeed6d14b1 Support non-binary kconfig options in kernel feature source
Discover other than bool or tristate kconfig options, too. For bool and
tristate the node label is still binary (i.e. set to "true" if the
kconfig option has been enabled). For other kconfig types (e.g. string
or int) the value of the label directly corresponds to the value of the
kconfig flag, e.g. "32", "elf64-x86-64" etc.
2019-02-22 22:15:25 +02:00

194 lines
4.3 KiB
Go

/*
Copyright 2018 The Kubernetes Authors.
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 kernel
import (
"bytes"
"compress/gzip"
"io/ioutil"
"log"
"os"
"regexp"
"strings"
"k8s.io/apimachinery/pkg/util/validation"
"sigs.k8s.io/node-feature-discovery/source"
)
// Configuration file options
type NFDConfig struct {
KconfigFile string
ConfigOpts []string `json:"configOpts,omitempty"`
}
var logger = log.New(os.Stderr, "", log.LstdFlags)
var Config = NFDConfig{
KconfigFile: "",
ConfigOpts: []string{
"NO_HZ",
"NO_HZ_IDLE",
"NO_HZ_FULL",
"PREEMPT",
},
}
// Implement FeatureSource interface
type Source struct{}
func (s Source) Name() string { return "kernel" }
func (s Source) Discover() (source.Features, error) {
features := source.Features{}
// Read kernel version
version, err := parseVersion()
if err != nil {
logger.Printf("ERROR: Failed to get kernel version: %s", err)
} else {
for key := range version {
features["version."+key] = version[key]
}
}
// Read kconfig
kconfig, err := parseKconfig()
if err != nil {
logger.Printf("ERROR: Failed to read kconfig: %s", err)
}
// Check flags
for _, opt := range Config.ConfigOpts {
if val, ok := kconfig[opt]; ok {
features["config."+opt] = val
}
}
selinux, err := SelinuxEnabled()
if err != nil {
logger.Print(err)
} else if selinux {
features["selinux.enabled"] = true
}
return features, nil
}
// Read and parse kernel version
func parseVersion() (map[string]string, error) {
version := map[string]string{}
// Open file for reading
raw, err := ioutil.ReadFile("/proc/sys/kernel/osrelease")
if err != nil {
return nil, err
}
full := strings.TrimSpace(string(raw))
version["full"] = full
// Regexp for parsing version components
re := regexp.MustCompile(`^(?P<major>\d+)(\.(?P<minor>\d+))?(\.(?P<revision>\d+))?(-.*)?$`)
if m := re.FindStringSubmatch(full); m != nil {
for i, name := range re.SubexpNames() {
if i != 0 && name != "" {
version[name] = m[i]
}
}
}
return version, nil
}
// Read gzipped kernel config
func readKconfigGzip(filename string) ([]byte, error) {
// Open file for reading
f, err := os.Open(filename)
if err != nil {
return nil, err
}
defer f.Close()
// Uncompress data
r, err := gzip.NewReader(f)
if err != nil {
return nil, err
}
defer r.Close()
return ioutil.ReadAll(r)
}
// Read kconfig into a map
func parseKconfig() (map[string]string, error) {
kconfig := map[string]string{}
raw := []byte(nil)
err := error(nil)
// First, try kconfig specified in the config file
if len(Config.KconfigFile) > 0 {
raw, err = ioutil.ReadFile(Config.KconfigFile)
if err != nil {
logger.Printf("ERROR: Failed to read kernel config from %s: %s", Config.KconfigFile, err)
}
}
// Then, try to read from /proc
if raw == nil {
raw, err = readKconfigGzip("/proc/config.gz")
if err != nil {
logger.Printf("Failed to read /proc/config.gz: %s", err)
}
}
// Last, try to read from /boot/
if raw == nil {
// Get kernel version
unameRaw, err := ioutil.ReadFile("/proc/sys/kernel/osrelease")
uname := strings.TrimSpace(string(unameRaw))
if err != nil {
return nil, err
}
// Read kconfig
raw, err = ioutil.ReadFile("/host-boot/config-" + uname)
if err != nil {
return nil, err
}
}
// Regexp for matching kconfig flags
re := regexp.MustCompile(`^CONFIG_(?P<flag>\w+)=(?P<value>.+)`)
// Process data, line-by-line
lines := bytes.Split(raw, []byte("\n"))
for _, line := range lines {
if m := re.FindStringSubmatch(string(line)); m != nil {
if m[2] == "y" || m[2] == "m" {
kconfig[m[1]] = "true"
} else {
value := strings.Trim(m[2], `"`)
if len(value) > validation.LabelValueMaxLength {
logger.Printf("WARNING: ignoring kconfig option '%s': value exceeds max length of %d characters", m[1], validation.LabelValueMaxLength)
continue
}
kconfig[m[1]] = value
}
}
}
return kconfig, nil
}