1 /*
2 * Copyright (C) 2021 Huawei Device Co., Ltd.
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 "platform/include/random.h"
17 #include <fcntl.h>
18 #include <unistd.h>
19 #include "platform/include/platform_def.h"
20
21 static int g_fd = -1;
22
GetRandomFd()23 static int GetRandomFd()
24 {
25 if (g_fd >= 0) {
26 return g_fd;
27 }
28
29 g_fd = open("/dev/random", O_RDONLY | O_NONBLOCK);
30 if (g_fd == -1) {
31 LOG_ERROR("Open random-device failed... error no: %{public}d.", errno);
32 return -1;
33 }
34
35 return g_fd;
36 }
37
CloseRandomFd()38 static void CloseRandomFd()
39 {
40 if (g_fd == -1) {
41 return;
42 }
43 (void)close(g_fd);
44 g_fd = -1;
45 }
46
RandomGenerate()47 uint32_t RandomGenerate()
48 {
49 uint32_t val = 0;
50 int rfd = GetRandomFd();
51 if (rfd != -1) {
52 if (read(rfd, &val, sizeof(val)) == -1) {
53 LOG_ERROR("Read random-device failed... error no: %{public}d.", errno);
54 }
55 CloseRandomFd();
56 }
57 return val;
58 }