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e0edde6f | 1 | /* Copyright (c) 2008, 2009, 2010, 2011 Nicira, Inc. |
e251c8d0 BP |
2 | * |
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: | |
6 | * | |
7 | * http://www.apache.org/licenses/LICENSE-2.0 | |
8 | * | |
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. | |
14 | */ | |
15 | ||
16 | #include <config.h> | |
17 | ||
18 | #include "entropy.h" | |
19 | ||
20 | #include <errno.h> | |
21 | #include <fcntl.h> | |
22 | #include <unistd.h> | |
23 | ||
24 | #include "socket-util.h" | |
25 | #include "vlog.h" | |
26 | ||
d98e6007 | 27 | VLOG_DEFINE_THIS_MODULE(entropy); |
e251c8d0 BP |
28 | |
29 | static const char urandom[] = "/dev/urandom"; | |
30 | ||
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. */ | |
33 | int | |
34 | get_entropy(void *buffer, size_t n) | |
35 | { | |
36 | size_t bytes_read; | |
37 | int error; | |
38 | int fd; | |
39 | ||
40 | fd = open(urandom, O_RDONLY); | |
41 | if (fd < 0) { | |
42 | VLOG_ERR("%s: open failed (%s)", urandom, strerror(errno)); | |
43 | return errno ? errno : EINVAL; | |
44 | } | |
45 | ||
46 | error = read_fully(fd, buffer, n, &bytes_read); | |
47 | close(fd); | |
48 | ||
49 | if (error) { | |
fe1e967e | 50 | VLOG_ERR("%s: read error (%s)", urandom, ovs_retval_to_string(error)); |
e251c8d0 BP |
51 | } |
52 | return error; | |
53 | } | |
54 | ||
55 | /* Initializes 'buffer' with 'n' bytes of high-quality random numbers. Exits | |
56 | * if an error occurs. */ | |
57 | void | |
58 | get_entropy_or_die(void *buffer, size_t n) | |
59 | { | |
60 | int error = get_entropy(buffer, n); | |
61 | if (error) { | |
279c9e03 BP |
62 | VLOG_FATAL("%s: read error (%s)", |
63 | urandom, ovs_retval_to_string(error)); | |
e251c8d0 BP |
64 | } |
65 | } |