// Copyright (c) 2015-2022 MinIO, Inc.//// This file is part of MinIO Object Storage stack//// This program is free software: you can redistribute it and/or modify// it under the terms of the GNU Affero General Public License as published by// the Free Software Foundation, either version 3 of the License, or// (at your option) any later version.//// This program is distributed in the hope that it will be useful// but WITHOUT ANY WARRANTY; without even the implied warranty of// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the// GNU Affero General Public License for more details.//// You should have received a copy of the GNU Affero General Public License// along with this program.  If not, see <http://www.gnu.org/licenses/>. //go:build linux// +build linux package kernel import (	"fmt"	"io/ioutil"	"regexp"	"strconv"	"strings"	"syscall") var versionRegex = regexp.MustCompile(`^(\d+)\.(\d+).(\d+).*$`) // VersionFromRelease 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 VersionFromRelease(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	}	return Version(major, minor, patch), nil} // Version implements KERNEL_VERSION equivalent macro// #define KERNEL_VERSION(a,b,c) (((a) << 16) + ((b) << 8) + ((c) > 255 ? 255 : (c)))func Version(major, minor, patch int) uint32 {	if patch > 255 {		patch = 255	}	out := major<<16 + minor<<8 + patch	return uint32(out)} 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 VersionFromRelease(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 VersionFromRelease(releaseString)} var debianVersionRegex = regexp.MustCompile(`.* SMP Debian (\d+\.\d+.\d+-\d+)(?:\+[[:alnum:]]*)?.*`) func parseDebianVersion(str string) (uint32, error) {	match := debianVersionRegex.FindStringSubmatch(str)	if len(match) != 2 {		return 0, fmt.Errorf("failed to parse kernel version from /proc/version: %s", str)	}	return VersionFromRelease(match[1])} func currentVersionDebian() (uint32, error) {	procVersion, err := ioutil.ReadFile("/proc/version")	if err != nil {		return 0, fmt.Errorf("error reading /proc/version: %s", err)	} 	return parseDebianVersion(string(procVersion))} // CurrentVersion returns the current kernel version in// LINUX_VERSION_CODE format (see VersionFromRelease())func CurrentVersion() (uint32, error) {	// We need extra checks for Debian and Ubuntu as they modify	// the kernel version patch number for compatibility 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-team.pages.debian.net/kernel-handbook/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()}