providers/linux/boottime_linux.go

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// the Apache License, Version 2.0 (the "License"); you may
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// You may obtain a copy of the License at
//
//     http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing,
// software distributed under the License is distributed on an
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package linux

import (
	"sync"
	"time"

	"github.com/prometheus/procfs"
)

var (
	bootTimeValue time.Time  // Cached boot time.
	bootTimeLock  sync.Mutex // Lock that guards access to bootTime.
)

func bootTime(fs procfs.FS) (time.Time, error) {
	bootTimeLock.Lock()
	defer bootTimeLock.Unlock()

	if !bootTimeValue.IsZero() {
		return bootTimeValue, nil
	}

	stat, err := fs.Stat()
	if err != nil {
		return time.Time{}, err
	}

	bootTimeValue = time.Unix(int64(stat.BootTime), 0)
	return bootTimeValue, nil
}