From 638e7dc12a692c515eb2b6ca795df24d031fafb1 Mon Sep 17 00:00:00 2001
From: henrygd <hank@henrygd.me>
Date: Sun, 8 Mar 2026 13:34:16 -0400
Subject: [PATCH] fix(smart): handle negative ATA device statistics values
 (#1791)

---
 agent/smart.go                   |  4 ++--
 agent/smart_test.go              | 37 ++++++++++++++++++++++++++++++++
 internal/entities/smart/smart.go |  4 ++--
 3 files changed, 41 insertions(+), 4 deletions(-)

diff --git a/agent/smart.go b/agent/smart.go
index d3a131dd..c2598518 100644
--- a/agent/smart.go
+++ b/agent/smart.go
@@ -223,7 +223,7 @@ func (sm *SmartManager) ScanDevices(force bool) error {
 }
 
 func (sm *SmartManager) parseConfiguredDevices(config string) ([]*DeviceInfo, error) {
-	splitChar := os.Getenv("SMART_DEVICES_SEPARATOR")
+	splitChar, _ := utils.GetEnv("SMART_DEVICES_SEPARATOR")
 	if splitChar == "" {
 		splitChar = ","
 	}
@@ -919,7 +919,7 @@ func temperatureFromAtaDeviceStatistics(stats smart.AtaDeviceStatistics) (uint8,
 	if entry == nil || entry.Value == nil {
 		return 0, false
 	}
-	if *entry.Value > 255 {
+	if *entry.Value < 0 || *entry.Value > 255 {
 		return 0, false
 	}
 	return uint8(*entry.Value), true
diff --git a/agent/smart_test.go b/agent/smart_test.go
index 14add02f..8ff7c6df 100644
--- a/agent/smart_test.go
+++ b/agent/smart_test.go
@@ -121,6 +121,43 @@ func TestParseSmartForSataDeviceStatisticsTemperature(t *testing.T) {
 	assert.Equal(t, uint8(22), deviceData.Temperature)
 }
 
+func TestParseSmartForSataNegativeDeviceStatistics(t *testing.T) {
+	// Tests that negative values in ata_device_statistics (e.g. min operating temp)
+	// do not cause the entire SAT parser to fail.
+	jsonPayload := []byte(`{
+		"smartctl": {"exit_status": 0},
+		"device": {"name": "/dev/sdb", "type": "sat"},
+		"model_name": "SanDisk SSD U110 16GB",
+		"serial_number": "NEGATIVE123",
+		"firmware_version": "U21B001",
+		"user_capacity": {"bytes": 16013942784},
+		"smart_status": {"passed": true},
+		"temperature": {"current": 38},
+		"ata_smart_attributes": {"table": []},
+		"ata_device_statistics": {
+			"pages": [
+				{
+					"number": 5,
+					"name": "Temperature Statistics",
+					"table": [
+						{"name": "Current Temperature", "value": 38, "flags": {"valid": true}},
+						{"name": "Specified Minimum Operating Temperature", "value": -20, "flags": {"valid": true}}
+					]
+				}
+			]
+		}
+	}`)
+
+	sm := &SmartManager{SmartDataMap: make(map[string]*smart.SmartData)}
+	hasData, exitStatus := sm.parseSmartForSata(jsonPayload)
+	require.True(t, hasData)
+	assert.Equal(t, 0, exitStatus)
+
+	deviceData, ok := sm.SmartDataMap["NEGATIVE123"]
+	require.True(t, ok, "expected smart data entry for serial NEGATIVE123")
+	assert.Equal(t, uint8(38), deviceData.Temperature)
+}
+
 func TestParseSmartForSataParentheticalRawValue(t *testing.T) {
 	jsonPayload := []byte(`{
 		"smartctl": {"exit_status": 0},
diff --git a/internal/entities/smart/smart.go b/internal/entities/smart/smart.go
index 2a7b11f3..cda462e4 100644
--- a/internal/entities/smart/smart.go
+++ b/internal/entities/smart/smart.go
@@ -143,8 +143,8 @@ type AtaDeviceStatisticsPage struct {
 }
 
 type AtaDeviceStatisticsEntry struct {
-	Name  string  `json:"name"`
-	Value *uint64 `json:"value,omitempty"`
+	Name  string `json:"name"`
+	Value *int64 `json:"value,omitempty"`
 }
 
 type AtaSmartAttribute struct {