helpers/osinfo: export functions to access internal fields

Reference: #60
Reference: #61

helpers/osinfo.go

@@ -4,7 +4,6 @@ import (
 	"bufio"
 	"fmt"
 	"os"
-	"strconv"
 	"strings"
 )
 
@@ -47,7 +46,7 @@ var osReleaseIDToString = map[OSReleaseID]string{
 }
 
 const (
-	OS_NAME osReleaseField = iota + 0
+	OS_NAME OSReleaseField = iota + 0
 	OS_ID
 	OS_ID_LIKE
 	OS_PRETTY_NAME
@@ -62,14 +61,14 @@ const (
 	OS_KERNEL_RELEASE // not part of default os-release, but we can use it here to facilitate things
 )
 
-type osReleaseField uint32
+type OSReleaseField uint32
 
-func (o osReleaseField) String() string {
+func (o OSReleaseField) String() string {
 	return osReleaseFieldToString[o]
 }
 
-// StringToOSReleaseField is a map of os-release file fields
-var stringToOSReleaseField = map[string]osReleaseField{
+// stringToOSReleaseField is a map of os-release file fields
+var stringToOSReleaseField = map[string]OSReleaseField{
 	"NAME":             OS_NAME,
 	"ID":               OS_ID,
 	"ID_LIKE":          OS_ID_LIKE,
@@ -85,8 +84,8 @@ var stringToOSReleaseField = map[string]osReleaseField{
 	"KERNEL_RELEASE":   OS_KERNEL_RELEASE,
 }
 
-// OSReleaseFieldToString is a map of os-release file fields
-var osReleaseFieldToString = map[osReleaseField]string{
+// osReleaseFieldToString is a map of os-release file fields
+var osReleaseFieldToString = map[OSReleaseField]string{
 	OS_NAME:             "NAME",
 	OS_ID:               "ID",
 	OS_ID_LIKE:          "ID_LIKE",
@@ -102,42 +101,6 @@ var osReleaseFieldToString = map[osReleaseField]string{
 	OS_KERNEL_RELEASE:   "KERNEL_RELEASE",
 }
 
-// CompareOSBaseKernelRelease will compare two given kernel version/release
-// strings and return -1, 0 or 1 if given version is less, equal or bigger,
-// respectively, than the given one
-//
-// Examples of $(uname -r):
-//
-// 5.11.0-31-generic (ubuntu)
-// 4.18.0-305.12.1.el8_4.x86_64 (alma)
-// 4.18.0-338.el8.x86_64 (stream8)
-// 4.18.0-305.7.1.el8_4.centos.x86_64 (centos)
-// 4.18.0-305.7.1.el8_4.centos.plus.x86_64 (centos + plus repo)
-// 5.13.13-arch1-1 (archlinux)
-//
-func CompareOSBaseKernelRelease(base, given string) int {
-	b := strings.Split(base, "-") // [base]-xxx
-	b = strings.Split(b[0], ".")  // [major][minor][patch]
-
-	g := strings.Split(given, "-")
-	g = strings.Split(g[0], ".")
-
-	for n := 0; n <= 2; n++ {
-		i, _ := strconv.Atoi(g[n])
-		j, _ := strconv.Atoi(b[n])
-
-		if i > j {
-			return 1 // given is bigger
-		} else if i < j {
-			return -1 // given is less
-		} else {
-			continue // equal
-		}
-	}
-
-	return 0 // equal
-}
-
 // OSBTFEnabled checks if kernel has embedded BTF vmlinux file
 func OSBTFEnabled() bool {
 	_, err := os.Stat("/sys/kernel/btf/vmlinux") // TODO: accept a KernelConfig param and check for CONFIG_DEBUG_INFO_BTF=y, or similar
@@ -150,20 +113,20 @@ func GetOSInfo() (*OSInfo, error) {
 	info := OSInfo{}
 	var err error
 
-	if info.OSReleaseInfo == nil {
-		info.OSReleaseInfo = make(map[osReleaseField]string)
+	if info.osReleaseFieldValues == nil {
+		info.osReleaseFieldValues = make(map[OSReleaseField]string)
 	}
 
-	info.OSReleaseInfo[OS_KERNEL_RELEASE], err = UnameRelease()
+	info.osReleaseFieldValues[OS_KERNEL_RELEASE], err = UnameRelease()
 	if err != nil {
 		return &info, fmt.Errorf("could not determine uname release: %w", err)
 	}
 
-	info.OSReleaseFilePath, err = checkEnvPath("LIBBPFGO_OSRELEASE_FILE") // useful if users wants to mount host os-release in a container
+	info.osReleaseFilePath, err = checkEnvPath("LIBBPFGO_OSRELEASE_FILE") // useful if users wants to mount host os-release in a container
 	if err != nil {
 		return &info, err
-	} else if info.OSReleaseFilePath == "" {
-		info.OSReleaseFilePath = "/etc/os-release"
+	} else if info.osReleaseFilePath == "" {
+		info.osReleaseFilePath = "/etc/os-release"
 	}
 
 	if err = info.discoverOSDistro(); err != nil {
@@ -177,12 +140,39 @@ func GetOSInfo() (*OSInfo, error) {
 //
 // OSRelease is relevant to examples such as:
 // 1) OSInfo.OSReleaseInfo[helpers.OS_KERNEL_RELEASE]) => will provide $(uname -r) string
-// 2) if OSInfo.OSRelease == helpers.UBUNTU => {} will allow to run code in specific distros
+// 2) if OSInfo.GetReleaseID() == helpers.UBUNTU => {} will allow to run code in specific distribution
 //
 type OSInfo struct {
-	OSReleaseInfo     map[osReleaseField]string
-	OSRelease         OSReleaseID
-	OSReleaseFilePath string
+	osReleaseFieldValues map[OSReleaseField]string
+	osReleaseID          OSReleaseID
+	osReleaseFilePath    string
+}
+
+// GetOSReleaseFieldValue provides access to internal OSInfo OSReleaseField's
+func (btfi *OSInfo) GetOSReleaseFieldValue(value OSReleaseField) string {
+	return btfi.osReleaseFieldValues[value]
+}
+
+// GetOSReleaseFilePath provides the path for the used os-release file as it might
+// not necessarily be /etc/os-release, depending on the environment variable
+func (btfi *OSInfo) GetOSReleaseFilePath() string {
+	return btfi.osReleaseFilePath
+}
+
+// GetOSReleaseFilePath provides the ID of current Linux distribution
+func (btfi *OSInfo) GetOSReleaseID() OSReleaseID {
+	return btfi.osReleaseID
+}
+
+// GetOSReleaseAllFieldValues allows user to dump, as strings, the existing OSReleaseField's and its values
+func (btfi *OSInfo) GetOSReleaseAllFieldValues() map[OSReleaseField]string {
+	summary := make(map[OSReleaseField]string)
+
+	for k, v := range btfi.osReleaseFieldValues {
+		summary[k] = v // create a copy so consumer can read internal data (e.g. debugging)
+	}
+
+	return summary
 }
 
 // CompareOSBaseKernelRelease will compare a given kernel version/release string
@@ -192,19 +182,19 @@ type OSInfo struct {
 // OSInfo.CompareOSBaseKernelRelease("5.11.0"))
 //
 func (btfi *OSInfo) CompareOSBaseKernelRelease(version string) int {
-	return CompareOSBaseKernelRelease(btfi.OSReleaseInfo[OS_KERNEL_RELEASE], version)
+	return CompareKernelRelease(btfi.osReleaseFieldValues[OS_KERNEL_RELEASE], version)
 }
 
 // discoverOSDistro discover running Linux distribution information by reading UTS and
 // the /etc/os-releases file (https://man7.org/linux/man-pages/man5/os-release.5.html)
 func (btfi *OSInfo) discoverOSDistro() error {
 	var err error
 
-	if btfi.OSReleaseFilePath == "" {
+	if btfi.osReleaseFilePath == "" {
 		return fmt.Errorf("should specify os-release filepath")
 	}
 
-	file, err := os.Open(btfi.OSReleaseFilePath)
+	file, err := os.Open(btfi.osReleaseFilePath)
 	if err != nil {
 		return err
 	}
@@ -221,9 +211,9 @@ func (btfi *OSInfo) discoverOSDistro() error {
 		if keyID == 0 { // could not find KEY= from os-release in consts
 			continue
 		}
-		btfi.OSReleaseInfo[keyID] = val[1]
+		btfi.osReleaseFieldValues[keyID] = val[1]
 		if keyID == OS_ID {
-			btfi.OSRelease = stringToOSReleaseID[strings.ToLower(val[1])]
+			btfi.osReleaseID = stringToOSReleaseID[strings.ToLower(val[1])]
 		}
 	}