SMART: add eMMC health via sysfs (#1736)

* SMART: add eMMC health via sysfs

Read eMMC wear/EOL indicators from /sys/class/block/mmcblk*/device and expose in SMART device list. Includes mocked sysfs tests and UI tweaks for unknown temps.

* small optimizations for emmc scan and parsing

* smart: keep smartctl optional only for Linux hosts with eMMC

* update smart alerts to handle warning state

* refactor: rename binPath to smartctlPath and replace hasSmartctl with smartctlPath checks

---------

Co-authored-by: henrygd <hank@henrygd.me>

agent/emmc_linux.go

@@ -0,0 +1,227 @@
+//go:build linux
+
+package agent
+
+import (
+	"os"
+	"path/filepath"
+	"strconv"
+	"strings"
+
+	"github.com/henrygd/beszel/internal/entities/smart"
+)
+
+// emmcSysfsRoot is a test hook; production value is "/sys".
+var emmcSysfsRoot = "/sys"
+
+type emmcHealth struct {
+	model    string
+	serial   string
+	revision string
+	capacity uint64
+	preEOL   uint8
+	lifeA    uint8
+	lifeB    uint8
+}
+
+func scanEmmcDevices() []*DeviceInfo {
+	blockDir := filepath.Join(emmcSysfsRoot, "class", "block")
+	entries, err := os.ReadDir(blockDir)
+	if err != nil {
+		return nil
+	}
+
+	devices := make([]*DeviceInfo, 0, 2)
+	for _, ent := range entries {
+		name := ent.Name()
+		if !isEmmcBlockName(name) {
+			continue
+		}
+
+		deviceDir := filepath.Join(blockDir, name, "device")
+		if !hasEmmcHealthFiles(deviceDir) {
+			continue
+		}
+
+		devPath := filepath.Join("/dev", name)
+		devices = append(devices, &DeviceInfo{
+			Name:     devPath,
+			Type:     "emmc",
+			InfoName: devPath + " [eMMC]",
+			Protocol: "MMC",
+		})
+	}
+
+	return devices
+}
+
+func (sm *SmartManager) collectEmmcHealth(deviceInfo *DeviceInfo) (bool, error) {
+	if deviceInfo == nil || deviceInfo.Name == "" {
+		return false, nil
+	}
+
+	base := filepath.Base(deviceInfo.Name)
+	if !isEmmcBlockName(base) && !strings.EqualFold(deviceInfo.Type, "emmc") && !strings.EqualFold(deviceInfo.Type, "mmc") {
+		return false, nil
+	}
+
+	health, ok := readEmmcHealth(base)
+	if !ok {
+		return false, nil
+	}
+
+	// Normalize the device type to keep pruning logic stable across refreshes.
+	deviceInfo.Type = "emmc"
+
+	key := health.serial
+	if key == "" {
+		key = filepath.Join("/dev", base)
+	}
+
+	status := emmcSmartStatus(health.preEOL)
+
+	attrs := []*smart.SmartAttribute{
+		{
+			Name:      "PreEOLInfo",
+			RawValue:  uint64(health.preEOL),
+			RawString: emmcPreEOLString(health.preEOL),
+		},
+		{
+			Name:      "DeviceLifeTimeEstA",
+			RawValue:  uint64(health.lifeA),
+			RawString: emmcLifeTimeString(health.lifeA),
+		},
+		{
+			Name:      "DeviceLifeTimeEstB",
+			RawValue:  uint64(health.lifeB),
+			RawString: emmcLifeTimeString(health.lifeB),
+		},
+	}
+
+	sm.Lock()
+	defer sm.Unlock()
+
+	if _, exists := sm.SmartDataMap[key]; !exists {
+		sm.SmartDataMap[key] = &smart.SmartData{}
+	}
+
+	data := sm.SmartDataMap[key]
+	data.ModelName = health.model
+	data.SerialNumber = health.serial
+	data.FirmwareVersion = health.revision
+	data.Capacity = health.capacity
+	data.Temperature = 0
+	data.SmartStatus = status
+	data.DiskName = filepath.Join("/dev", base)
+	data.DiskType = "emmc"
+	data.Attributes = attrs
+
+	return true, nil
+}
+
+func readEmmcHealth(blockName string) (emmcHealth, bool) {
+	var out emmcHealth
+
+	if !isEmmcBlockName(blockName) {
+		return out, false
+	}
+
+	deviceDir := filepath.Join(emmcSysfsRoot, "class", "block", blockName, "device")
+	preEOL, okPre := readHexByteFile(filepath.Join(deviceDir, "pre_eol_info"))
+
+	// Some kernels expose EXT_CSD lifetime via "life_time" (two bytes), others as
+	// separate files. Support both.
+	lifeA, lifeB, okLife := readLifeTime(deviceDir)
+
+	if !okPre && !okLife {
+		return out, false
+	}
+
+	out.preEOL = preEOL
+	out.lifeA = lifeA
+	out.lifeB = lifeB
+
+	out.model = readStringFile(filepath.Join(deviceDir, "name"))
+	out.serial = readStringFile(filepath.Join(deviceDir, "serial"))
+	out.revision = readStringFile(filepath.Join(deviceDir, "prv"))
+
+	if capBytes, ok := readBlockCapacityBytes(blockName); ok {
+		out.capacity = capBytes
+	}
+
+	return out, true
+}
+
+func readLifeTime(deviceDir string) (uint8, uint8, bool) {
+	if content, ok := readStringFileOK(filepath.Join(deviceDir, "life_time")); ok {
+		a, b, ok := parseHexBytePair(content)
+		return a, b, ok
+	}
+
+	a, okA := readHexByteFile(filepath.Join(deviceDir, "device_life_time_est_typ_a"))
+	b, okB := readHexByteFile(filepath.Join(deviceDir, "device_life_time_est_typ_b"))
+	if okA || okB {
+		return a, b, true
+	}
+	return 0, 0, false
+}
+
+func readBlockCapacityBytes(blockName string) (uint64, bool) {
+	sizePath := filepath.Join(emmcSysfsRoot, "class", "block", blockName, "size")
+	lbsPath := filepath.Join(emmcSysfsRoot, "class", "block", blockName, "queue", "logical_block_size")
+
+	sizeStr, ok := readStringFileOK(sizePath)
+	if !ok {
+		return 0, false
+	}
+	sectors, err := strconv.ParseUint(sizeStr, 10, 64)
+	if err != nil || sectors == 0 {
+		return 0, false
+	}
+
+	lbsStr, ok := readStringFileOK(lbsPath)
+	logicalBlockSize := uint64(512)
+	if ok {
+		if parsed, err := strconv.ParseUint(lbsStr, 10, 64); err == nil && parsed > 0 {
+			logicalBlockSize = parsed
+		}
+	}
+
+	return sectors * logicalBlockSize, true
+}
+
+func readHexByteFile(path string) (uint8, bool) {
+	content, ok := readStringFileOK(path)
+	if !ok {
+		return 0, false
+	}
+	b, ok := parseHexOrDecByte(content)
+	return b, ok
+}
+
+func readStringFile(path string) string {
+	content, _ := readStringFileOK(path)
+	return content
+}
+
+func readStringFileOK(path string) (string, bool) {
+	b, err := os.ReadFile(path)
+	if err != nil {
+		return "", false
+	}
+	return strings.TrimSpace(string(b)), true
+}
+
+func hasEmmcHealthFiles(deviceDir string) bool {
+	entries, err := os.ReadDir(deviceDir)
+	if err != nil {
+		return false
+	}
+	for _, ent := range entries {
+		switch ent.Name() {
+		case "pre_eol_info", "life_time", "device_life_time_est_typ_a", "device_life_time_est_typ_b":
+			return true
+		}
+	}
+	return false
+}