//
// Copyright (c) 2016 Intel Corporation
//
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
//
//      http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.
//

package main

import (
	"bufio"
	"io"
	"os"
	"sync"
	"syscall"
)

type nbRandReader struct {
	f    io.Reader
	lock sync.Mutex
}

func (r *nbRandReader) Read(p []byte) (int, error) {
	r.lock.Lock()
	n, err := r.f.Read(p)
	r.lock.Unlock()
	if re, ok := err.(*os.PathError); ok {
		if re, ok := re.Err.(syscall.Errno); ok {
			if re == syscall.EAGAIN {
				err = nil
			}
		}
	}

	return n, err
}

func init() {
	r, err := os.Open("/dev/urandom")
	if err != nil {
		return
	}

	cnciRand = &nbRandReader{f: bufio.NewReader(r)}
}
