/*
    This file is part of libcapwap.

    libcapwap is free software: you can redistribute it and/or modify
    it under the terms of the GNU General Public License as published by
    the Free Software Foundation, either version 3 of the License, or
    (at your option) any later version.

    libcapwap is distributed in the hope that it will be useful,
    but WITHOUT ANY WARRANTY; without even the implied warranty of
    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
    GNU General Public License for more details.

    You should have received a copy of the GNU General Public License
    along with Foobar.  If not, see <http://www.gnu.org/licenses/>.

*/

#include <stdint.h>
#include <stdio.h>
#include <string.h>
#include <errno.h>
#include <unistd.h>

#include <sys/types.h>
#include <sys/stat.h>
#include <fcntl.h>

#include "cw_util.h"
#include "cw_log.h"

char * cw_rand_dev = "/dev/random";

int cw_rand(uint8_t*dst, int len)
{
	int rf;
	int l;

 	rf = open(cw_rand_dev, O_RDONLY | O_NDELAY); 
	if (rf<0){

		cw_log(LOG_ERR,"Can't open %s: %s",cw_rand_dev,strerror(errno));
		return cw_pseudo_rand(dst,len);
	}


	l = read(rf, dst, len);
	close(rf);

	if ((l<0) && (errno != EAGAIN)){
		cw_log(LOG_ERR,"Cant read from %s: %s",cw_rand_dev,strerror(errno));
		return cw_pseudo_rand(dst,len);
	}

	if (l<len){
		cw_log_debug2("Not enough entropy reading from %s, using pseudo rand",cw_rand_dev);
		return cw_pseudo_rand(dst,len);
	}
	
	return l;
}