1 /* Copyright (c) 2008, 2009, 2010 Nicira Networks
3 * Licensed under the Apache License, Version 2.0 (the "License");
4 * you may not use this file except in compliance with the License.
5 * You may obtain a copy of the License at:
7 * http://www.apache.org/licenses/LICENSE-2.0
9 * Unless required by applicable law or agreed to in writing, software
10 * distributed under the License is distributed on an "AS IS" BASIS,
11 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
12 * See the License for the specific language governing permissions and
13 * limitations under the License.
24 #include "socket-util.h"
27 VLOG_DEFINE_THIS_MODULE(entropy);
29 static const char urandom[] = "/dev/urandom";
31 /* Initializes 'buffer' with 'n' bytes of high-quality random numbers. Returns
32 * 0 if successful, otherwise a positive errno value or EOF on error. */
34 get_entropy(void *buffer, size_t n)
40 fd = open(urandom, O_RDONLY);
42 VLOG_ERR("%s: open failed (%s)", urandom, strerror(errno));
43 return errno ? errno : EINVAL;
46 error = read_fully(fd, buffer, n, &bytes_read);
50 VLOG_ERR("%s: read error (%s)", urandom,
51 error == EOF ? "unexpected end of file" : strerror(error));
56 /* Initializes 'buffer' with 'n' bytes of high-quality random numbers. Exits
57 * if an error occurs. */
59 get_entropy_or_die(void *buffer, size_t n)
61 int error = get_entropy(buffer, n);
63 ovs_fatal(error, "%s: read error", urandom);