mirror of https://github.com/hashicorp/consul
35 lines
732 B
Go
35 lines
732 B
Go
package lib
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import (
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crand "crypto/rand"
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"math"
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"math/big"
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"math/rand"
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"sync"
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"time"
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)
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var (
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once sync.Once
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// SeededSecurely is set to true if a cryptographically secure seed
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// was used to initialize rand. When false, the start time is used
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// as a seed.
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SeededSecurely bool
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)
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// SeedMathRand provides weak, but guaranteed seeding, which is better than
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// running with Go's default seed of 1. A call to SeedMathRand() is expected
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// to be called via init(), but never a second time.
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func SeedMathRand() {
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once.Do(func() {
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n, err := crand.Int(crand.Reader, big.NewInt(math.MaxInt64))
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if err != nil {
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rand.Seed(time.Now().UTC().UnixNano())
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return
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}
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rand.Seed(n.Int64())
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SeededSecurely = true
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})
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}
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