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openvswitch/lib/entropy.c
Alin Serdean 5d386c0613 entropy: Add Windows support.
Signed-off-by: Alin Serdean <aserdean at cloudbasesolutions.com>
Signed-off-by: Ben Pfaff <blp@nicira.com>
2013-12-19 09:20:33 -08:00

95 lines
2.5 KiB
C

/* Copyright (c) 2008, 2009, 2010, 2011, 2013 Nicira, Inc.
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at:
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
#include <config.h>
#include "entropy.h"
#include <errno.h>
#include <fcntl.h>
#include <unistd.h>
#ifdef _WIN32
#include <Wincrypt.h>
#endif
#include "socket-util.h"
#include "vlog.h"
VLOG_DEFINE_THIS_MODULE(entropy);
static const char urandom[] = "/dev/urandom";
/* Initializes 'buffer' with 'n' bytes of high-quality random numbers. Returns
* 0 if successful, otherwise a positive errno value or EOF on error. */
int
get_entropy(void *buffer, size_t n)
{
#ifndef _WIN32
size_t bytes_read;
int error;
int fd;
fd = open(urandom, O_RDONLY);
if (fd < 0) {
VLOG_ERR("%s: open failed (%s)", urandom, ovs_strerror(errno));
return errno ? errno : EINVAL;
}
error = read_fully(fd, buffer, n, &bytes_read);
close(fd);
if (error) {
VLOG_ERR("%s: read error (%s)", urandom, ovs_retval_to_string(error));
}
#else
int error = 0;
HCRYPTPROV crypt_prov = 0;
LPVOID msg_buf;
CryptAcquireContext(&crypt_prov, NULL, NULL,
PROV_RSA_FULL, CRYPT_VERIFYCONTEXT);
if (!CryptGenRandom(crypt_prov, n, buffer)) {
error = EINVAL;
FormatMessage(FORMAT_MESSAGE_ALLOCATE_BUFFER
| FORMAT_MESSAGE_FROM_SYSTEM
| FORMAT_MESSAGE_IGNORE_INSERTS,
NULL,
GetLastError(),
0,
(LPTSTR)&msg_buf,
0,
NULL
);
VLOG_ERR("CryptGenRandom: read error (%s)", msg_buf);
LocalFree(msg_buf);
}
CryptReleaseContext(crypt_prov, 0);
#endif
return error;
}
/* Initializes 'buffer' with 'n' bytes of high-quality random numbers. Exits
* if an error occurs. */
void
get_entropy_or_die(void *buffer, size_t n)
{
int error = get_entropy(buffer, n);
if (error) {
VLOG_FATAL("%s: read error (%s)",
urandom, ovs_retval_to_string(error));
}
}