source: perform all sysfs discovery under host sysfs

Be consistent and do all sysfs based feature discovery under the same
sysfs directory.

source/cpu/cpu.go

@@ -19,15 +19,10 @@ package cpu
 import (
 	"io/ioutil"
 	"log"
-	"path"
 
 	"sigs.k8s.io/node-feature-discovery/source"
 )
 
-const (
-	cpuDevicesBaseDir = "/sys/bus/cpu/devices"
-)
-
 // Configuration file options
 type cpuidConfig struct {
 	AttributeBlacklist []string `json:"attributeBlacklist,omitempty"`
@@ -137,14 +132,15 @@ func (s Source) Discover() (source.Features, error) {
 
 // Check if any (online) CPUs have thread siblings
 func haveThreadSiblings() (bool, error) {
-	files, err := ioutil.ReadDir(cpuDevicesBaseDir)
+
+	files, err := ioutil.ReadDir(source.SysfsDir.Path("bus/cpu/devices"))
 	if err != nil {
 		return false, err
 	}
 
 	for _, file := range files {
 		// Try to read siblings from topology
-		siblings, err := ioutil.ReadFile(path.Join(cpuDevicesBaseDir, file.Name(), "topology/thread_siblings_list"))
+		siblings, err := ioutil.ReadFile(source.SysfsDir.Path("bus/cpu/devices", file.Name(), "topology/thread_siblings_list"))
 		if err != nil {
 			return false, err
 		}

source/cpu/power_amd64.go

@@ -20,11 +20,11 @@ import (
 	"fmt"
 	"io/ioutil"
 	"os"
-	"path"
 	"strconv"
 	"strings"
 
 	"sigs.k8s.io/node-feature-discovery/pkg/cpuid"
+	"sigs.k8s.io/node-feature-discovery/source"
 )
 
 const (
@@ -38,13 +38,14 @@ func discoverSSTBF() (bool, error) {
 	nominalBaseFrequency := int(freqInfo.EAX)
 
 	// Loop over all CPUs in the system
-	files, err := ioutil.ReadDir(cpuDevicesBaseDir)
+	files, err := ioutil.ReadDir(source.SysfsDir.Path("bus/cpu/devices"))
+
 	if err != nil {
 		return false, err
 	}
 	for _, file := range files {
 		// Try to read effective base frequency of each cpu in the system
-		filePath := path.Join(cpuDevicesBaseDir, file.Name(), "cpufreq/base_frequency")
+		filePath := source.SysfsDir.Path("bus/cpu/devices", file.Name(), "cpufreq/base_frequency")
 		data, err := ioutil.ReadFile(filePath)
 		if os.IsNotExist(err) {
 			// Ignore missing file and continue to check other CPUs

source/cpu/pstate.go

@@ -20,6 +20,8 @@ import (
 	"fmt"
 	"io/ioutil"
 	"runtime"
+
+	"sigs.k8s.io/node-feature-discovery/source"
 )
 
 // Discover p-state related features such as turbo boost.
@@ -31,7 +33,7 @@ func detectPstate() (map[string]string, error) {
 	}
 
 	// Only looking for turbo boost for now...
-	bytes, err := ioutil.ReadFile("/sys/devices/system/cpu/intel_pstate/no_turbo")
+	bytes, err := ioutil.ReadFile(source.SysfsDir.Path("devices/system/cpu/intel_pstate/no_turbo"))
 	if err != nil {
 		return nil, fmt.Errorf("can't detect whether turbo boost is enabled: %s", err.Error())
 	}

source/internal/pci_utils.go

@@ -22,6 +22,8 @@ import (
 	"log"
 	"path"
 	"strings"
+
+	"sigs.k8s.io/node-feature-discovery/source"
 )
 
 type PciDeviceInfo map[string]string
@@ -72,10 +74,10 @@ func readPciDevInfo(devPath string, deviceAttrSpec map[string]bool) (PciDeviceIn
 // "class" attribute is considered mandatory.
 // DetectPci() will fail if the retrieval of a mandatory attribute fails.
 func DetectPci(deviceAttrSpec map[string]bool) (map[string][]PciDeviceInfo, error) {
-	const basePath = "/sys/bus/pci/devices/"
+	sysfsBasePath := source.SysfsDir.Path("bus/pci/devices")
 	devInfo := make(map[string][]PciDeviceInfo)
 
-	devices, err := ioutil.ReadDir(basePath)
+	devices, err := ioutil.ReadDir(sysfsBasePath)
 	if err != nil {
 		return nil, err
 	}
@@ -84,7 +86,7 @@ func DetectPci(deviceAttrSpec map[string]bool) (map[string][]PciDeviceInfo, erro
 
 	// Iterate over devices
 	for _, device := range devices {
-		info, err := readPciDevInfo(path.Join(basePath, device.Name()), deviceAttrSpec)
+		info, err := readPciDevInfo(path.Join(sysfsBasePath, device.Name()), deviceAttrSpec)
 		if err != nil {
 			log.Print(err)
 			continue

source/iommu/iommu.go

@@ -32,7 +32,7 @@ func (s Source) Discover() (source.Features, error) {
 	features := source.Features{}
 
 	// Check if any iommu devices are available
-	devices, err := ioutil.ReadDir("/sys/class/iommu/")
+	devices, err := ioutil.ReadDir(source.SysfsDir.Path("class/iommu/"))
 	if err != nil {
 		return nil, fmt.Errorf("Failed to check for IOMMU support: %v", err)
 	}

source/memory/memory.go

@@ -60,7 +60,7 @@ func (s Source) Discover() (source.Features, error) {
 func isNuma() (bool, error) {
 	// Find out how many nodes are online
 	// Multiple nodes is a sign of NUMA
-	bytes, err := ioutil.ReadFile("/sys/devices/system/node/online")
+	bytes, err := ioutil.ReadFile(source.SysfsDir.Path("devices/system/node/online"))
 	if err != nil {
 		return false, err
 	}
@@ -81,7 +81,7 @@ func detectNvdimm() (map[string]bool, error) {
 	features := make(map[string]bool)
 
 	// Check presence of physical devices
-	devices, err := ioutil.ReadDir("/sys/class/nd/")
+	devices, err := ioutil.ReadDir(source.SysfsDir.Path("class/nd"))
 	if err == nil {
 		if len(devices) > 0 {
 			features["present"] = true
@@ -93,7 +93,7 @@ func detectNvdimm() (map[string]bool, error) {
 	}
 
 	// Check presence of DAX-configured regions
-	devices, err = ioutil.ReadDir("/sys/bus/nd/devices/")
+	devices, err = ioutil.ReadDir(source.SysfsDir.Path("bus/nd/devices"))
 	if err == nil {
 		for _, d := range devices {
 			if strings.HasPrefix(d.Name(), "dax") {

source/network/network.go

@@ -44,8 +44,7 @@ func (s Source) Discover() (source.Features, error) {
 	// iterating through network interfaces to obtain their respective number of virtual functions
 	for _, netInterface := range netInterfaces {
 		if strings.Contains(netInterface.Flags.String(), "up") && !strings.Contains(netInterface.Flags.String(), "loopback") {
-			totalVfsPath := "/sys/class/net/" + netInterface.Name + "/device/sriov_totalvfs"
+			totalBytes, err := ioutil.ReadFile(source.SysfsDir.Path("class/net", netInterface.Name, "device/sriov_totalvfs"))
-			totalBytes, err := ioutil.ReadFile(totalVfsPath)
 			if err != nil {
 				log.Printf("SR-IOV not supported for network interface: %s: %v", netInterface.Name, err)
 				continue
@@ -60,8 +59,7 @@ func (s Source) Discover() (source.Features, error) {
 				log.Printf("SR-IOV capability is detected on the network interface: %s", netInterface.Name)
 				log.Printf("%d maximum supported number of virtual functions on network interface: %s", t, netInterface.Name)
 				features["sriov.capable"] = true
-				numVfsPath := "/sys/class/net/" + netInterface.Name + "/device/sriov_numvfs"
+				numBytes, err := ioutil.ReadFile(source.SysfsDir.Path("class/net", netInterface.Name, "device/sriov_numvfs"))
-				numBytes, err := ioutil.ReadFile(numVfsPath)
 				if err != nil {
 					log.Printf("SR-IOV not configured for network interface: %s: %s", netInterface.Name, err)
 					continue

source/storage/storage.go

@@ -34,10 +34,10 @@ func (s Source) Discover() (source.Features, error) {
 	features := source.Features{}
 
 	// Check if there is any non-rotational block devices attached to the node
-	blockdevices, err := ioutil.ReadDir("/sys/block/")
+	blockdevices, err := ioutil.ReadDir(source.SysfsDir.Path("block"))
 	if err == nil {
 		for _, bdev := range blockdevices {
-			fname := "/sys/block/" + bdev.Name() + "/queue/rotational"
+			fname := source.SysfsDir.Path("block", bdev.Name(), "queue/rotational")
 			bytes, err := ioutil.ReadFile(fname)
 			if err != nil {
 				return nil, fmt.Errorf("can't read rotational status: %s", err.Error())