rand_getentropy.go

     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  
     7  package rand
     8  
     9  import (
    10  	"internal/syscall/unix"
    11  )
    12  
    13  func init() {
    14  	altGetRandom = getEntropy
    15  }
    16  
    17  func getEntropy(p []byte) error {
    18  	// getentropy(2) returns a maximum of 256 bytes per call
    19  	for i := 0; i < len(p); i += 256 {
    20  		end := i + 256
    21  		if len(p) < end {
    22  			end = len(p)
    23  		}
    24  		err := unix.GetEntropy(p[i:end])
    25  		if err != nil {
    26  			return err
    27  		}
    28  	}
    29  	return nil
    30  }
    31
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