From d50d7c4ebc5ed9532730de5b68174548884a0d92 Mon Sep 17 00:00:00 2001
From: Sean Swehla <sean@sweh.la>
Date: Thu, 27 Mar 2025 17:23:39 -0400
Subject: [PATCH] Use SysReadFile for thermals and skip failed zones

Switches all calls in the thermal zones processing to use SysReadFile so
that unavailable zones won't stall forever waiting for them to become
available. Also continues processing in the case that one zone fails
with EAGAIN, as is the case for temporarily unavailable zones.

Addresses #698

Signed-off-by: Sean Swehla <sean@sweh.la>
---
 internal/util/sysreadfile.go | 20 ++++++++++++++++++++
 sysfs/class_thermal.go       |  6 +++---
 2 files changed, 23 insertions(+), 3 deletions(-)

diff --git a/internal/util/sysreadfile.go b/internal/util/sysreadfile.go
index 1ab875ce..d5404a6d 100644
--- a/internal/util/sysreadfile.go
+++ b/internal/util/sysreadfile.go
@@ -20,6 +20,8 @@ package util
 import (
 	"bytes"
 	"os"
+	"strconv"
+	"strings"
 	"syscall"
 )
 
@@ -48,3 +50,21 @@ func SysReadFile(file string) (string, error) {
 
 	return string(bytes.TrimSpace(b[:n])), nil
 }
+
+// SysReadUintFromFile reads a file using SysReadFile and attempts to parse a uint64 from it.
+func SysReadUintFromFile(path string) (uint64, error) {
+	data, err := SysReadFile(path)
+	if err != nil {
+		return 0, err
+	}
+	return strconv.ParseUint(strings.TrimSpace(string(data)), 10, 64)
+}
+
+// SysReadIntFromFile reads a file using SysReadFile and attempts to parse a int64 from it.
+func SysReadIntFromFile(path string) (int64, error) {
+	data, err := SysReadFile(path)
+	if err != nil {
+		return 0, err
+	}
+	return strconv.ParseInt(strings.TrimSpace(string(data)), 10, 64)
+}
diff --git a/sysfs/class_thermal.go b/sysfs/class_thermal.go
index 10f4a9a7..19706c0b 100644
--- a/sysfs/class_thermal.go
+++ b/sysfs/class_thermal.go
@@ -51,7 +51,7 @@ func (fs FS) ClassThermalZoneStats() ([]ClassThermalZoneStats, error) {
 	for _, zone := range zones {
 		zoneStats, err := parseClassThermalZone(zone)
 		if err != nil {
-			if errors.Is(err, syscall.ENODATA) || errors.As(err, new(*fsp.PathError)) {
+			if errors.Is(err, syscall.ENODATA) || errors.As(err, new(*fsp.PathError)) || errors.Is(err, syscall.EAGAIN) {
 				continue
 			}
 			return nil, err
@@ -72,7 +72,7 @@ func parseClassThermalZone(zone string) (ClassThermalZoneStats, error) {
 	if err != nil {
 		return ClassThermalZoneStats{}, err
 	}
-	zoneTemp, err := util.ReadIntFromFile(filepath.Join(zone, "temp"))
+	zoneTemp, err := util.SysReadIntFromFile(filepath.Join(zone, "temp"))
 	if err != nil {
 		return ClassThermalZoneStats{}, err
 	}
@@ -85,7 +85,7 @@ func parseClassThermalZone(zone string) (ClassThermalZoneStats, error) {
 	zoneMode := util.ParseBool(mode)
 
 	var zonePassive *uint64
-	passive, err := util.ReadUintFromFile(filepath.Join(zone, "passive"))
+	passive, err := util.SysReadUintFromFile(filepath.Join(zone, "passive"))
 	if os.IsNotExist(err) || os.IsPermission(err) {
 		zonePassive = nil
 	} else if err != nil {