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/* SPDX-License-Identifier: LGPL-2.1-or-later */
#pragma once
#include <stdbool.h>
#include <stddef.h>
#include <stdint.h>
typedef enum RandomFlags {
RANDOM_EXTEND_WITH_PSEUDO = 1 << 0, /* If we can't get enough genuine randomness, but some, fill up the rest with pseudo-randomness */
RANDOM_BLOCK = 1 << 1, /* Rather block than return crap randomness (only if the kernel supports that) */
RANDOM_MAY_FAIL = 1 << 2, /* If we can't get any randomness at all, return early with -ENODATA */
RANDOM_ALLOW_RDRAND = 1 << 3, /* Allow usage of the CPU RNG */
RANDOM_ALLOW_INSECURE = 1 << 4, /* Allow usage of GRND_INSECURE flag to kernel's getrandom() API */
} RandomFlags;
int genuine_random_bytes(void *p, size_t n, RandomFlags flags); /* returns "genuine" randomness, optionally filled up with pseudo random, if not enough is available */
void pseudo_random_bytes(void *p, size_t n); /* returns only pseudo-randommess (but possibly seeded from something better) */
void random_bytes(void *p, size_t n); /* returns genuine randomness if cheaply available, and pseudo randomness if not. */
void initialize_srand(void);
static inline uint64_t random_u64(void) {
uint64_t u;
random_bytes(&u, sizeof(u));
return u;
}
static inline uint32_t random_u32(void) {
uint32_t u;
random_bytes(&u, sizeof(u));
return u;
}
int rdrand(unsigned long *ret);
/* Some limits on the pool sizes when we deal with the kernel random pool */
#define RANDOM_POOL_SIZE_MIN 512U
#define RANDOM_POOL_SIZE_MAX (10U*1024U*1024U)
size_t random_pool_size(void);
int random_write_entropy(int fd, const void *seed, size_t size, bool credit);
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