mirror of
https://github.com/autc04/Retro68.git
synced 2024-07-30 19:29:09 +00:00
40 lines
894 B
Go
40 lines
894 B
Go
// Copyright 2021 The Go Authors. All rights reserved.
|
|
// Use of this source code is governed by a BSD-style
|
|
// license that can be found in the LICENSE file.
|
|
|
|
//go:build dragonfly || freebsd || linux
|
|
|
|
package unix
|
|
|
|
import (
|
|
"sync/atomic"
|
|
"syscall"
|
|
"unsafe"
|
|
)
|
|
|
|
var getrandomUnsupported int32 // atomic
|
|
|
|
// GetRandomFlag is a flag supported by the getrandom system call.
|
|
type GetRandomFlag uintptr
|
|
|
|
// GetRandom calls the getrandom system call.
|
|
func GetRandom(p []byte, flags GetRandomFlag) (n int, err error) {
|
|
if len(p) == 0 {
|
|
return 0, nil
|
|
}
|
|
if atomic.LoadInt32(&getrandomUnsupported) != 0 {
|
|
return 0, syscall.ENOSYS
|
|
}
|
|
r1, _, errno := syscall.Syscall(getrandomTrap,
|
|
uintptr(unsafe.Pointer(&p[0])),
|
|
uintptr(len(p)),
|
|
uintptr(flags))
|
|
if errno != 0 {
|
|
if errno == syscall.ENOSYS {
|
|
atomic.StoreInt32(&getrandomUnsupported, 1)
|
|
}
|
|
return 0, errno
|
|
}
|
|
return int(r1), nil
|
|
}
|