134 lines
3.0 KiB
Go
134 lines
3.0 KiB
Go
package diskio
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import (
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"bufio"
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"bytes"
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"errors"
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"fmt"
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"io/fs"
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"os"
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"path/filepath"
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"strings"
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"golang.org/x/sys/unix"
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)
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type diskInfoCache struct {
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modifiedAt int64 // Unix Nano timestamp of the last modification of the device. This value is used to invalidate the cache
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udevDataPath string
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values map[string]string
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}
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func (d *DiskIO) diskInfo(devName string) (map[string]string, error) {
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var err error
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var stat unix.Stat_t
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path := "/dev/" + devName
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err = unix.Stat(path, &stat)
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if err != nil {
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return nil, err
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}
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if d.infoCache == nil {
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d.infoCache = map[string]diskInfoCache{}
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}
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ic, ok := d.infoCache[devName]
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if ok && stat.Mtim.Nano() == ic.modifiedAt {
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return ic.values, nil
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}
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var udevDataPath string
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if ok && len(ic.udevDataPath) > 0 {
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// We can reuse the udev data path from a "previous" entry.
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// This allows us to also "poison" it during test scenarios
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udevDataPath = ic.udevDataPath
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} else {
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major := unix.Major(uint64(stat.Rdev)) //nolint:unconvert // Conversion needed for some architectures
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minor := unix.Minor(uint64(stat.Rdev)) //nolint:unconvert // Conversion needed for some architectures
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udevDataPath = fmt.Sprintf("/run/udev/data/b%d:%d", major, minor)
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_, err := os.Stat(udevDataPath)
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if err != nil {
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// This path failed, try the fallback .udev style (non-systemd)
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udevDataPath = fmt.Sprintf("/dev/.udev/db/block:%s", devName)
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_, err := os.Stat(udevDataPath)
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if err != nil {
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// Giving up, cannot retrieve disk info
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return nil, err
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}
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}
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}
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// Final open of the confirmed (or the previously detected/used) udev file
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f, err := os.Open(udevDataPath)
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if err != nil {
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return nil, err
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}
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defer f.Close()
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di := map[string]string{}
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d.infoCache[devName] = diskInfoCache{
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modifiedAt: stat.Mtim.Nano(),
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udevDataPath: udevDataPath,
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values: di,
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}
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scnr := bufio.NewScanner(f)
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var devlinks bytes.Buffer
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for scnr.Scan() {
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l := scnr.Text()
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if len(l) < 4 {
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continue
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}
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if l[:2] == "S:" {
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if devlinks.Len() > 0 {
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devlinks.WriteString(" ") //nolint:revive // this will never fail
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}
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devlinks.WriteString("/dev/") //nolint:revive // this will never fail
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devlinks.WriteString(l[2:]) //nolint:revive // this will never fail
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continue
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}
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if l[:2] != "E:" {
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continue
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}
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kv := strings.SplitN(l[2:], "=", 2)
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if len(kv) < 2 {
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continue
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}
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di[kv[0]] = kv[1]
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}
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if devlinks.Len() > 0 {
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di["DEVLINKS"] = devlinks.String()
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}
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return di, nil
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}
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func resolveName(name string) string {
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resolved, err := filepath.EvalSymlinks(name)
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if err == nil {
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return resolved
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}
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if err != nil && !errors.Is(err, fs.ErrNotExist) {
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return name
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}
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// Try to prepend "/dev"
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resolved, err = filepath.EvalSymlinks(filepath.Join("/dev", name))
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if err != nil {
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return name
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}
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return resolved
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}
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func getDeviceWWID(name string) string {
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path := fmt.Sprintf("/sys/block/%s/wwid", filepath.Base(name))
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buf, err := os.ReadFile(path)
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if err != nil {
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return ""
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}
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return strings.TrimSuffix(string(buf), "\n")
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}
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