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      1 /*	$NetBSD: rumpuser_random.c,v 1.4 2014/11/04 19:05:17 pooka Exp $	*/
      2 
      3 /*
      4  * Copyright (c) 2014 Justin Cormack.  All Rights Reserved.
      5  *
      6  * Redistribution and use in source and binary forms, with or without
      7  * modification, are permitted provided that the following conditions
      8  * are met:
      9  * 1. Redistributions of source code must retain the above copyright
     10  *    notice, this list of conditions and the following disclaimer.
     11  * 2. Redistributions in binary form must reproduce the above copyright
     12  *    notice, this list of conditions and the following disclaimer in the
     13  *    documentation and/or other materials provided with the distribution.
     14  *
     15  * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS
     16  * OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
     17  * WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
     18  * DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
     19  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
     20  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR
     21  * SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
     22  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
     23  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
     24  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
     25  * SUCH DAMAGE.
     26  */
     27 
     28 #include "rumpuser_port.h"
     29 
     30 #if !defined(lint)
     31 __RCSID("$NetBSD: rumpuser_random.c,v 1.4 2014/11/04 19:05:17 pooka Exp $");
     32 #endif /* !lint */
     33 
     34 #include <sys/types.h>
     35 
     36 #include <assert.h>
     37 #include <errno.h>
     38 #include <fcntl.h>
     39 #include <stdint.h>
     40 #include <stdio.h>
     41 #include <stdlib.h>
     42 #include <string.h>
     43 #include <unistd.h>
     44 
     45 #include <rump/rumpuser.h>
     46 
     47 #include "rumpuser_int.h"
     48 
     49 static const size_t random_maxread = 32;
     50 
     51 #ifdef HAVE_ARC4RANDOM_BUF
     52 int
     53 rumpuser__random_init(void)
     54 {
     55 
     56 	return 0;
     57 }
     58 #else
     59 static const char *random_device = "/dev/urandom";
     60 static int random_fd = -1;
     61 
     62 int
     63 rumpuser__random_init(void)
     64 {
     65 
     66 	random_fd = open(random_device, O_RDONLY);
     67 	if (random_fd < 0) {
     68 		fprintf(stderr, "random init open failed\n");
     69 		return errno;
     70 	}
     71 	return 0;
     72 }
     73 #endif
     74 
     75 int
     76 rumpuser_getrandom(void *buf, size_t buflen, int flags, size_t *retp)
     77 {
     78 #ifndef HAVE_ARC4RANDOM_BUF
     79 	ssize_t rv;
     80 
     81 	rv = read(random_fd, buf, buflen > random_maxread ? random_maxread : buflen);
     82 	if (rv < 0) {
     83 		ET(errno);
     84 	}
     85 	*retp = rv;
     86 #else
     87 	buflen = buflen > random_maxread ? random_maxread : buflen;
     88 	arc4random_buf(buf, buflen);
     89 	*retp = buflen;
     90 #endif
     91 
     92 	return 0;
     93 }
     94