1 /* SPDX-License-Identifier: LGPL-2.1+ */
8 typedef enum RandomFlags
{
9 RANDOM_EXTEND_WITH_PSEUDO
= 1 << 0, /* If we can't get enough genuine randomness, but some, fill up the rest with pseudo-randomness */
10 RANDOM_BLOCK
= 1 << 1, /* Rather block than return crap randomness (only if the kernel supports that) */
11 RANDOM_DONT_DRAIN
= 1 << 2, /* If we can't get any randomness at all, return early with -EAGAIN */
12 RANDOM_ALLOW_RDRAND
= 1 << 3, /* Allow usage of the CPU RNG */
15 int genuine_random_bytes(void *p
, size_t n
, RandomFlags flags
); /* returns "genuine" randomness, optionally filled upwith pseudo random, if not enough is available */
16 void pseudo_random_bytes(void *p
, size_t n
); /* returns only pseudo-randommess (but possibly seeded from something better) */
17 void random_bytes(void *p
, size_t n
); /* returns genuine randomness if cheaply available, and pseudo randomness if not. */
19 void initialize_srand(void);
21 static inline uint64_t random_u64(void) {
23 random_bytes(&u
, sizeof(u
));
27 static inline uint32_t random_u32(void) {
29 random_bytes(&u
, sizeof(u
));
33 int rdrand(unsigned long *ret
);