/*
 * Copyright (c) 2010 Kungliga Tekniska Högskolan
 * (Royal Institute of Technology, Stockholm, Sweden).
 * All rights reserved.
 *
 * Portions Copyright (c) 2010 Apple Inc. All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 *
 * 1. Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer.
 *
 * 2. Redistributions in binary form must reproduce the above copyright
 *    notice, this list of conditions and the following disclaimer in the
 *    documentation and/or other materials provided with the distribution.
 *
 * 3. Neither the name of the Institute nor the names of its contributors
 *    may be used to endorse or promote products derived from this software
 *    without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE INSTITUTE AND CONTRIBUTORS ``AS IS'' AND
 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
 * ARE DISCLAIMED.  IN NO EVENT SHALL THE INSTITUTE OR CONTRIBUTORS BE LIABLE
 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
 * SUCH DAMAGE.
 */

#include <config.h>

#include <sys/types.h>
#include <fcntl.h>
#include <errno.h>
#include <unistd.h>

#include <krb5-types.h>

#include "roken.h"

#include <CommonCrypto/CommonCryptor.h>
#include "CCDGlue.h"

static int
_hc_unix_device_fd(int flags, const char **fn)
{
    static const char *rnd_devices[] = {
	"/dev/urandom",
	"/dev/random",
	"/dev/srandom",
	"/dev/arandom",
	NULL
    };
    const char **p;

    for(p = rnd_devices; *p; p++) {
	int fd = open(*p, flags | O_NDELAY);
	if(fd >= 0) {
	    if (fn)
		*fn = *p;
	    rk_cloexec(fd);
	    return fd;
	}
    }
    return -1;
}

int
CCRandomCopyBytes(CCRandomRef source, void *data, size_t size)
{
    uint8_t *outdata = data;
    ssize_t count;
    int fd;

    if (size == 0)
	return 0;

    fd = _hc_unix_device_fd(O_RDONLY, NULL);
    if (fd < 0)
	return EINVAL;

    while (size > 0) {
	count = read(fd, outdata, size);
	if (count < 0 && errno == EINTR)
	    continue;
	else if (count <= 0) {
	    close(fd);
	    return EINVAL;
	}
	outdata += count;
	size -= count;
    }
    close(fd);

    return 1;
}