1 | #define _DEFAULT_SOURCE |
---|---|
2 | #include <unistd.h> |
3 | #include <sys/random.h> |
4 | #include <pthread.h> |
5 | #include <errno.h> |
6 | |
7 | int getentropy(void *buffer, size_t len) |
8 | { |
9 | int cs, ret = 0; |
10 | char *pos = buffer; |
11 | |
12 | if (len > 256) { |
13 | errno = EIO; |
14 | return -1; |
15 | } |
16 | |
17 | pthread_setcancelstate(PTHREAD_CANCEL_DISABLE, &cs); |
18 | |
19 | while (len) { |
20 | ret = getrandom(pos, len, 0); |
21 | if (ret < 0) { |
22 | if (errno == EINTR) continue; |
23 | else break; |
24 | } |
25 | pos += ret; |
26 | len -= ret; |
27 | ret = 0; |
28 | } |
29 | |
30 | pthread_setcancelstate(cs, 0); |
31 | |
32 | return ret; |
33 | } |
34 |