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rumpuser_random.c revision 1.2.2.2 
      1 /*
      2  * Copyright (c) 2014 Justin Cormack.  All Rights Reserved.
      3  *
      4  * Redistribution and use in source and binary forms, with or without
      5  * modification, are permitted provided that the following conditions
      6  * are met:
      7  * 1. Redistributions of source code must retain the above copyright
      8  *    notice, this list of conditions and the following disclaimer.
      9  * 2. Redistributions in binary form must reproduce the above copyright
     10  *    notice, this list of conditions and the following disclaimer in the
     11  *    documentation and/or other materials provided with the distribution.
     12  *
     13  * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS
     14  * OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
     15  * WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
     16  * DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
     17  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
     18  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR
     19  * SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
     20  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
     21  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
     22  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
     23  * SUCH DAMAGE.
     24  */
     25 
     26 #include "rumpuser_port.h"
     27 
     28 #if !defined(lint)
     29 __RCSID("$NetBSD: rumpuser_random.c,v 1.2.2.2 2014/08/10 06:52:26 tls Exp $");
     30 #endif /* !lint */
     31 
     32 #include <sys/types.h>
     33 
     34 #include <assert.h>
     35 #include <errno.h>
     36 #include <fcntl.h>
     37 #include <stdint.h>
     38 #include <stdio.h>
     39 #include <stdlib.h>
     40 #include <string.h>
     41 #include <unistd.h>
     42 
     43 #include <rump/rumpuser.h>
     44 
     45 #include "rumpuser_int.h"
     46 
     47 static const size_t random_maxread = 32;
     48 
     49 #ifdef PLATFORM_HAS_ARC4RANDOM_BUF
     50 int
     51 rumpuser__random_init(void)
     52 {
     53 
     54 	return 0;
     55 }
     56 #else
     57 static const char *random_device = "/dev/urandom";
     58 static int random_fd = -1;
     59 
     60 int
     61 rumpuser__random_init(void)
     62 {
     63 
     64 	random_fd = open(random_device, O_RDONLY);
     65 	if (random_fd < 0) {
     66 		fprintf(stderr, "random init open failed\n");
     67 		return errno;
     68 	}
     69 	return 0;
     70 }
     71 #endif
     72 
     73 int
     74 rumpuser_getrandom(void *buf, size_t buflen, int flags, size_t *retp)
     75 {
     76 #ifndef PLATFORM_HAS_ARC4RANDOM_BUF
     77 	ssize_t rv;
     78 
     79 	rv = read(random_fd, buf, buflen > random_maxread ? random_maxread : buflen);
     80 	if (rv < 0) {
     81 		ET(errno);
     82 	}
     83 	*retp = rv;
     84 #else
     85 	buflen = buflen > random_maxread ? random_maxread : buflen;
     86 	arc4random_buf(buf, buflen);
     87 	*retp = buflen;
     88 #endif
     89 
     90 	return 0;
     91 }
     92