Files
weave-scope/vendor/github.com/iovisor/gobpf/elf/kernel_version.go
2020-01-13 16:56:01 +00:00

113 lines
3.3 KiB
Go

// +build linux
// Copyright 2016-2017 Kinvolk
//
// 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 elf
import (
"fmt"
"io/ioutil"
"regexp"
"strconv"
"strings"
"syscall"
)
var versionRegex = regexp.MustCompile(`^(\d+)\.(\d+).(\d+).*$`)
// KernelVersionFromReleaseString converts a release string with format
// 4.4.2[-1] to a kernel version number in LINUX_VERSION_CODE format.
// That is, for kernel "a.b.c", the version number will be (a<<16 + b<<8 + c)
func KernelVersionFromReleaseString(releaseString string) (uint32, error) {
versionParts := versionRegex.FindStringSubmatch(releaseString)
if len(versionParts) != 4 {
return 0, fmt.Errorf("got invalid release version %q (expected format '4.3.2-1')", releaseString)
}
major, err := strconv.Atoi(versionParts[1])
if err != nil {
return 0, err
}
minor, err := strconv.Atoi(versionParts[2])
if err != nil {
return 0, err
}
patch, err := strconv.Atoi(versionParts[3])
if err != nil {
return 0, err
}
out := major*256*256 + minor*256 + patch
return uint32(out), nil
}
func currentVersionUname() (uint32, error) {
var buf syscall.Utsname
if err := syscall.Uname(&buf); err != nil {
return 0, err
}
releaseString := strings.Trim(utsnameStr(buf.Release[:]), "\x00")
return KernelVersionFromReleaseString(releaseString)
}
func currentVersionUbuntu() (uint32, error) {
procVersion, err := ioutil.ReadFile("/proc/version_signature")
if err != nil {
return 0, err
}
var u1, u2, releaseString string
_, err = fmt.Sscanf(string(procVersion), "%s %s %s", &u1, &u2, &releaseString)
if err != nil {
return 0, err
}
return KernelVersionFromReleaseString(releaseString)
}
var debianVersionRegex = regexp.MustCompile(`.* SMP Debian (\d+\.\d+.\d+-\d+) .*`)
func currentVersionDebian() (uint32, error) {
procVersion, err := ioutil.ReadFile("/proc/version")
if err != nil {
return 0, err
}
match := debianVersionRegex.FindStringSubmatch(string(procVersion))
if len(match) != 2 {
return 0, fmt.Errorf("failed to get kernel version from /proc/version: %s", procVersion)
}
return KernelVersionFromReleaseString(match[1])
}
// CurrentKernelVersion returns the current kernel version in
// LINUX_VERSION_CODE format (see KernelVersionFromReleaseString())
func CurrentKernelVersion() (uint32, error) {
// We need extra checks for Debian and Ubuntu as they modify
// the kernel version patch number for compatibilty with
// out-of-tree modules. Linux perf tools do the same for Ubuntu
// systems: https://github.com/torvalds/linux/commit/d18acd15c
//
// See also:
// https://kernel-handbook.alioth.debian.org/ch-versions.html
// https://wiki.ubuntu.com/Kernel/FAQ
version, err := currentVersionUbuntu()
if err == nil {
return version, nil
}
version, err = currentVersionDebian()
if err == nil {
return version, nil
}
return currentVersionUname()
}