firehol/netdata

// SPDX-License-Identifier: GPL-3.0-or-later

package smartctl

import (
    "errors"
    "fmt"
    "strings"
)

type scanDevice struct {
    name     string
    infoName string
    typ      string
    extra    bool // added via config "extra_devices"
}

func (s *scanDevice) key() string {
    return fmt.Sprintf("%s|%s", s.name, s.typ)
}

func (s *scanDevice) shortName() string {
    return strings.TrimPrefix(s.name, "/dev/")
}

func (s *Smartctl) scanDevices() (map[string]*scanDevice, error) {
    // Issue on Discord: https://discord.com/channels/847502280503590932/1261747175361347644/1261747175361347644
    // "sat" devices being identified as "scsi" with --scan, and then later
    // code attempts to validate the type by calling `smartctl` with the "scsi" type.
    // This validation can trigger unintended "Enabling discard_zeroes_data" messages in system logs (dmesg).
    // To address this specific issue we use `smartctl --scan-open` as a workaround.
    // This method reliably identifies device types.
    scanOpen := s.NoCheckPowerMode == "never"

    resp, err := s.exec.scan(scanOpen)
    if err != nil {
        return nil, fmt.Errorf("failed to scan devices: %v", err)
    }

    devices := make(map[string]*scanDevice)

    for _, d := range resp.Get("devices").Array() {
        dev := &scanDevice{
            name:     d.Get("name").String(),
            infoName: d.Get("info_name").String(),
            typ:      d.Get("type").String(),
        }

        if dev.name == "" || dev.typ == "" {
            s.Warningf("device info missing required fields (name: '%s', type: '%s'), skipping", dev.name, dev.typ)
            continue
        }

        if !s.deviceSr.MatchString(dev.infoName) {
            s.Debugf("device %s does not match selector, skipping it", dev.infoName)
            continue
        }

        if !scanOpen && dev.typ == "scsi" {
            // `smartctl --scan` attempts to guess the device type based on the path, but this can be unreliable.
            // Accurate device type information is crucial because we use the `--device` option to gather data.
            // Using the wrong type can lead to issues.
            // For example, using 'scsi' for 'sat' devices prevents `smartctl` from issuing the necessary ATA commands.

            s.handleGuessedScsiScannedDevice(dev)
        }

        s.Debugf("smartctl scan found device '%s' type '%s' info_name '%s'", dev.name, dev.typ, dev.infoName)

        devices[dev.key()] = dev
    }

    s.Debugf("smartctl scan found %d devices", len(devices))

    for _, v := range s.ExtraDevices {
        dev := &scanDevice{name: v.Name, typ: v.Type, extra: true}

        if _, ok := devices[dev.key()]; !ok {
            devices[dev.key()] = dev
        }
    }

    if len(devices) == 0 {
        return nil, errors.New("no devices found during scan")
    }

    return devices, nil
}

func (s *Smartctl) handleGuessedScsiScannedDevice(dev *scanDevice) {
    if dev.typ != "scsi" || s.hasScannedDevice(dev) {
        return
    }

    d := &scanDevice{name: dev.name, typ: "sat"}

    if s.hasScannedDevice(d) {
        dev.typ = d.typ
        return
    }

    resp, _ := s.exec.deviceInfo(dev.name, "sat", s.NoCheckPowerMode)
    if resp == nil || resp.Get("smartctl.exit_status").Int() != 0 {
        return
    }

    atts, ok := newSmartDevice(resp).ataSmartAttributeTable()
    if !ok || len(atts) == 0 {
        return
    }

    s.Debugf("changing device '%s' type 'scsi' -> 'sat'", dev.name)
    dev.typ = "sat"
}

func (s *Smartctl) hasScannedDevice(d *scanDevice) bool {
    _, ok := s.scannedDevices[d.key()]
    return ok
}