about summary refs log tree commit diff
path: root/src/misc/getentropy.c
blob: 4c61ae261ea329295dd22e89a599733b190741ae (plain) (blame)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
#include <sys/random.h>
#include <pthread.h>
#include <errno.h>

int getentropy(void *buffer, size_t len)
{
	int cs, ret;
	char *pos = buffer;

	if (len > 256) {
		errno = EIO;
		return -1;
	}

	pthread_setcancelstate(PTHREAD_CANCEL_DISABLE, &cs);

	while (len) {
		ret = getrandom(pos, len, 0);
		if (ret < 0) {
			if (errno == EINTR) continue;
			else break;
		}
		pos += ret;
		len -= ret;
		ret = 0;
	}

	pthread_setcancelstate(cs, 0);

	return ret;
}