Adding upstream version 1.34.4.

Signed-off-by: Daniel Baumann <daniel@debian.org>

plugins/inputs/diskio/diskio_linux.go

@@ -0,0 +1,192 @@
+package diskio
+
+import (
+	"bufio"
+	"bytes"
+	"errors"
+	"fmt"
+	"io/fs"
+	"os"
+	"path/filepath"
+	"strings"
+
+	"golang.org/x/sys/unix"
+)
+
+type diskInfoCache struct {
+	modifiedAt   int64 // Unix Nano timestamp of the last modification of the device. This value is used to invalidate the cache
+	udevDataPath string
+	sysBlockPath string
+	values       map[string]string
+}
+
+func (d *DiskIO) diskInfo(devName string) (map[string]string, error) {
+	// Check if the device exists
+	path := "/dev/" + devName
+	var stat unix.Stat_t
+	if err := unix.Stat(path, &stat); err != nil {
+		return nil, fmt.Errorf("error reading %s: %w", path, err)
+	}
+
+	// Check if we already got a cached and valid entry
+	ic, ok := d.infoCache[devName]
+	if ok && stat.Mtim.Nano() == ic.modifiedAt {
+		return ic.values, nil
+	}
+
+	// Determine udev properties
+	var udevDataPath string
+	if ok && len(ic.udevDataPath) > 0 {
+		// We can reuse the udev data path from a "previous" entry.
+		// This allows us to also "poison" it during test scenarios
+		udevDataPath = ic.udevDataPath
+	} else {
+		major := unix.Major(uint64(stat.Rdev)) //nolint:unconvert // Conversion needed for some architectures
+		minor := unix.Minor(uint64(stat.Rdev)) //nolint:unconvert // Conversion needed for some architectures
+		udevDataPath = fmt.Sprintf("/run/udev/data/b%d:%d", major, minor)
+		if _, err := os.Stat(udevDataPath); err != nil {
+			// This path failed, try the fallback .udev style (non-systemd)
+			udevDataPath = "/dev/.udev/db/block:" + devName
+			if _, err := os.Stat(udevDataPath); err != nil {
+				// Giving up, cannot retrieve disk info
+				return nil, fmt.Errorf("error reading %s: %w", udevDataPath, err)
+			}
+		}
+	}
+
+	info, err := readUdevData(udevDataPath)
+	if err != nil {
+		return nil, err
+	}
+
+	// Read additional (optional) device properties
+	var sysBlockPath string
+	if ok && len(ic.sysBlockPath) > 0 {
+		// We can reuse the /sys block path from a "previous" entry.
+		// This allows us to also "poison" it during test scenarios
+		sysBlockPath = ic.sysBlockPath
+	} else {
+		sysBlockPath = "/sys/class/block/" + devName
+	}
+
+	devInfo, err := readDevData(sysBlockPath)
+	if err == nil {
+		for k, v := range devInfo {
+			info[k] = v
+		}
+	} else if !errors.Is(err, os.ErrNotExist) {
+		return nil, err
+	}
+
+	d.infoCache[devName] = diskInfoCache{
+		modifiedAt:   stat.Mtim.Nano(),
+		udevDataPath: udevDataPath,
+		values:       info,
+	}
+
+	return info, nil
+}
+
+func readUdevData(path string) (map[string]string, error) {
+	// Final open of the confirmed (or the previously detected/used) udev file
+	f, err := os.Open(path)
+	if err != nil {
+		return nil, err
+	}
+	defer f.Close()
+
+	info := make(map[string]string)
+	scnr := bufio.NewScanner(f)
+	var devlinks bytes.Buffer
+	for scnr.Scan() {
+		l := scnr.Text()
+		if len(l) < 4 {
+			continue
+		}
+		if l[:2] == "S:" {
+			if devlinks.Len() > 0 {
+				devlinks.WriteString(" ")
+			}
+			devlinks.WriteString("/dev/")
+			devlinks.WriteString(l[2:])
+			continue
+		}
+		if l[:2] != "E:" {
+			continue
+		}
+		kv := strings.SplitN(l[2:], "=", 2)
+		if len(kv) < 2 {
+			continue
+		}
+		info[kv[0]] = kv[1]
+	}
+
+	if devlinks.Len() > 0 {
+		info["DEVLINKS"] = devlinks.String()
+	}
+
+	return info, nil
+}
+
+func readDevData(path string) (map[string]string, error) {
+	// Open the file and read line-wise
+	f, err := os.Open(filepath.Join(path, "uevent"))
+	if err != nil {
+		return nil, err
+	}
+	defer f.Close()
+
+	// Read DEVNAME and DEVTYPE
+	info := make(map[string]string)
+	scanner := bufio.NewScanner(f)
+	for scanner.Scan() {
+		line := scanner.Text()
+		if !strings.HasPrefix(line, "DEV") {
+			continue
+		}
+
+		k, v, found := strings.Cut(line, "=")
+		if !found {
+			continue
+		}
+		info[strings.TrimSpace(k)] = strings.TrimSpace(v)
+	}
+	if d, found := info["DEVNAME"]; found && !strings.HasPrefix(d, "/dev") {
+		info["DEVNAME"] = "/dev/" + d
+	}
+
+	// Find the DEVPATH property
+	if devlnk, err := filepath.EvalSymlinks(filepath.Join(path, "device")); err == nil {
+		devlnk = filepath.Join(devlnk, filepath.Base(path))
+		devlnk = strings.TrimPrefix(devlnk, "/sys")
+		info["DEVPATH"] = devlnk
+	}
+
+	return info, nil
+}
+
+func resolveName(name string) string {
+	resolved, err := filepath.EvalSymlinks(name)
+	if err == nil {
+		return resolved
+	}
+	if !errors.Is(err, fs.ErrNotExist) {
+		return name
+	}
+	// Try to prepend "/dev"
+	resolved, err = filepath.EvalSymlinks("/dev/" + name)
+	if err != nil {
+		return name
+	}
+
+	return resolved
+}
+
+func getDeviceWWID(name string) string {
+	path := fmt.Sprintf("/sys/block/%s/wwid", filepath.Base(name))
+	buf, err := os.ReadFile(path)
+	if err != nil {
+		return ""
+	}
+	return strings.TrimSuffix(string(buf), "\n")
+}