type reader struct {
	f    io.Reader
	mu   sync.Mutex
	used atomic.Uint32 // Atomic: 0 - never used, 1 - used, but f == nil, 2 - used, and f != nil
}

// altGetRandom if non-nil specifies an OS-specific function to get
// urandom-style randomness.
var altGetRandom func([]byte) (err error)

func warnBlocked() {
	println("crypto/rand: blocked for 60 seconds waiting to read random data from the kernel")
}

// license that can be found in the LICENSE file.

//go:build openbsd || netbsd

package rand

import "internal/syscall/unix"

func init() {
	// getentropy(2) returns a maximum of 256 bytes per call.
	altGetRandom = batched(unix.GetEntropy, 256)

	// regular basis, and also upon fork(2)." - arc4random(3)
	//
	// Note that despite its legacy name, it uses a secure CSPRNG (not RC4) in
	// all supported macOS versions.
	altGetRandom = func(b []byte) error { unix.ARC4Random(b); return nil }

		//     has a size of 32 bits.
		maxGetRandomRead = (1 << 25) - 1
	case "dragonfly", "freebsd", "illumos", "solaris":
		maxGetRandomRead = 1 << 8
	default:
		panic("no maximum specified for GetRandom")
	}
	altGetRandom = batched(getRandom, maxGetRandomRead)
}

// If the kernel is too old to support the getrandom syscall(),
// unix.GetRandom will immediately return ENOSYS and we will then fall back to