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/*
* Copyright (c) 2006 Kungliga Tekniska Högskolan
* (Royal Institute of Technology, Stockholm, Sweden).
* 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 <stdio.h>
#include <stdlib.h>
#include <rand.h>
#include <heim_threads.h>
#include <roken.h>
#include "randi.h"
static int random_fd = -1;
static HEIMDAL_MUTEX random_mutex = HEIMDAL_MUTEX_INITIALIZER;
/*
* Unix /dev/random
*/
static int
get_device_fd(int flags)
{
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) {
rk_cloexec(fd);
return fd;
}
}
return -1;
}
static void
unix_seed(const void *indata, int size)
{
int fd;
if (size <= 0)
return;
fd = get_device_fd(O_WRONLY);
if (fd < 0)
return;
write(fd, indata, size);
close(fd);
}
static int
unix_bytes(unsigned char *outdata, int size)
{
ssize_t count;
int once = 0;
if (size < 0)
return 0;
else if (size == 0)
return 1;
HEIMDAL_MUTEX_lock(&random_mutex);
if (random_fd == -1) {
retry:
random_fd = get_device_fd(O_RDONLY);
if (random_fd < 0) {
HEIMDAL_MUTEX_unlock(&random_mutex);
return 0;
}
}
while (size > 0) {
HEIMDAL_MUTEX_unlock(&random_mutex);
count = read (random_fd, outdata, size);
HEIMDAL_MUTEX_lock(&random_mutex);
if (random_fd < 0) {
if (errno == EINTR)
continue;
else if (errno == EBADF && once++ == 0) {
close(random_fd);
random_fd = -1;
goto retry;
}
return 0;
} else if (count <= 0) {
HEIMDAL_MUTEX_unlock(&random_mutex);
return 0;
}
outdata += count;
size -= count;
}
HEIMDAL_MUTEX_unlock(&random_mutex);
return 1;
}
static void
unix_cleanup(void)
{
}
static void
unix_add(const void *indata, int size, double entropi)
{
unix_seed(indata, size);
}
static int
unix_pseudorand(unsigned char *outdata, int size)
{
return unix_bytes(outdata, size);
}
static int
unix_status(void)
{
int fd;
fd = get_device_fd(O_RDONLY);
if (fd < 0)
return 0;
close(fd);
return 1;
}
const RAND_METHOD hc_rand_unix_method = {
unix_seed,
unix_bytes,
unix_cleanup,
unix_add,
unix_pseudorand,
unix_status
};
const RAND_METHOD *
RAND_unix_method(void)
{
return &hc_rand_unix_method;
}
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