fix: memory leak and string corruption in ARM Mac temperature sensors

[chuangbo]

This PR addresses several issues in the temperature sensor implementation for ARM Mac:

1. Memory leak caused by unreleased system resources
2. Increasing port counts in Activity Monitor
3. String corruption where the first character becomes "\x00"

Changes

1. Resource Management:

   • Added proper resource cleanup using defer statements
   • Refactored code to share the HID system client instead of creating new ones
   • Fixed memory leaks by ensuring all CoreFoundation objects are properly released

2. String Handling:

   • Fixed buffer allocation for string conversion
   • Properly handle null terminators in C string to Go string conversion
   • Added correct string length calculations

3. Code Structure:

   • Reduced resource allocation by sharing system client between functions
   • Enhanced code readability with better comments

Testing

Tested on Apple Silicon Mac with the following improvements:

• Memory usage remains stable over time
• Port count in Activity Monitor stays constant
• No more string corruption issues

How to Reproduce

You can reproduce these issues using the following code:

package main

import (
	"context"
	"time"

	"log/slog"

	"github.com/shirou/gopsutil/v4/sensors"
)

func main() {
	slog.SetLogLoggerLevel(slog.LevelDebug)
	ticker := time.NewTicker(10 * time.Millisecond)

	for range ticker.C {
		temps, err := sensors.TemperaturesWithContext(context.Background())
		if err != nil {
			slog.Debug("Sensor error", "err", err)
		}
		slog.Debug("Temperature", "sensors", temps)
	}
}

go run demo.go | grep "x00"

Memory leaks screen recordings: https://github.com/user-attachments/assets/0168feba-5637-4f3f-8a45-a56a3b5cbfdb

String corruption screenshot:

@uubulb would you mind taking a look? Many thanks!

[uubulb]

Thanks for the patch!

The original code was roughly ported from the original C code and lacks idiomatic style or additional checks for memory management, Maybe it's time for an overall refactoring

[shirou]

Thank you very much. The reproduction code and video were very clear. Unfortunately, I don't own a mac, so I can't verify the behavior myself, but it seems that @uubulb has also confirmed it, and the code itself looks fine. Thank you for your contribution!