1 /* Copyright libuv contributors. All rights reserved.
2 *
3 * Permission is hereby granted, free of charge, to any person obtaining a copy
4 * of this software and associated documentation files (the "Software"), to
5 * deal in the Software without restriction, including without limitation the
6 * rights to use, copy, modify, merge, publish, distribute, sublicense, and/or
7 * sell copies of the Software, and to permit persons to whom the Software is
8 * furnished to do so, subject to the following conditions:
9 *
10 * The above copyright notice and this permission notice shall be included in
11 * all copies or substantial portions of the Software.
12 *
13 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
14 * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
15 * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
16 * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
17 * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
18 * FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS
19 * IN THE SOFTWARE.
20 */
21
22 #include "uv.h"
23 #include "internal.h"
24
25 #include <stddef.h>
26 #include <dlfcn.h>
27
28 typedef int (*uv__getentropy_cb)(void *, size_t);
29
30 static uv__getentropy_cb uv__getentropy;
31 static uv_once_t once = UV_ONCE_INIT;
32
33
uv__random_getentropy_init(void)34 static void uv__random_getentropy_init(void) {
35 uv__getentropy = (uv__getentropy_cb) dlsym(RTLD_DEFAULT, "getentropy");
36 }
37
38
uv__random_getentropy(void * buf,size_t buflen)39 int uv__random_getentropy(void* buf, size_t buflen) {
40 size_t pos;
41 size_t stride;
42
43 uv_once(&once, uv__random_getentropy_init);
44
45 if (uv__getentropy == NULL)
46 return UV_ENOSYS;
47
48 /* getentropy() returns an error for requests > 256 bytes. */
49 for (pos = 0, stride = 256; pos + stride < buflen; pos += stride)
50 if (uv__getentropy((char *) buf + pos, stride))
51 return UV__ERR(errno);
52
53 if (uv__getentropy((char *) buf + pos, buflen - pos))
54 return UV__ERR(errno);
55
56 return 0;
57 }
58