/* 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" "github.com/kubernetes-incubator/node-feature-discovery/source" ) // Default kconfig flags var defaultKconfigFlags = [...]string{ "NO_HZ", "NO_HZ_IDLE", "NO_HZ_FULL", "PREEMPT", } var logger = log.New(os.Stderr, "", log.LstdFlags) // 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 _, flag := range defaultKconfigFlags { if _, ok := kconfig[flag]; ok { features["config."+flag] = 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\d+)(\.(?P\d+))?(\.(?P\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]bool, error) { kconfig := map[string]bool{} raw := []byte(nil) // First, try to read from /proc as this is the most reliable source raw, err := readKconfigGzip("/proc/config.gz") if err != nil { logger.Printf("ERROR: 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\w+)=(?P.+)`) // 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 } } } return kconfig, nil }