Source file src/crypto/rand/rand_getentropy.go

Documentation: crypto/rand

		 1  // Copyright 2016 The Go Authors. All rights reserved.
		 2  // Use of this source code is governed by a BSD-style
		 3  // license that can be found in the LICENSE file.
		 4  
		 5  //go:build (darwin && !ios) || openbsd
		 6  // +build darwin,!ios openbsd
		 7  
		 8  package rand
		 9  
		10  import (
		11  	"internal/syscall/unix"
		12  )
		13  
		14  func init() {
		15  	altGetRandom = getEntropy
		16  }
		17  
		18  func getEntropy(p []byte) error {
		19  	// getentropy(2) returns a maximum of 256 bytes per call
		20  	for i := 0; i < len(p); i += 256 {
		21  		end := i + 256
		22  		if len(p) < end {
		23  			end = len(p)
		24  		}
		25  		err := unix.GetEntropy(p[i:end])
		26  		if err != nil {
		27  			return err
		28  		}
		29  	}
		30  	return nil
		31  }
		32  

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