/*
 * LITLS -- CSPRNG via Linux getrandom(2) + secure utilities
 */

#include "litls.h"
#include <string.h>
#include <sys/random.h>

int litls_random_bytes(uint8_t *buf, size_t len) {
    while (len > 0) {
        ssize_t n = getrandom(buf, len, 0);
        if (n < 0)
            return -1;
        buf += n;
        len -= (size_t)n;
    }
    return 0;
}

void litls_secure_zero(void *buf, size_t len) {
    explicit_bzero(buf, len);
}

int litls_secure_memcmp(const uint8_t *a, const uint8_t *b, size_t len) {
    volatile uint8_t diff = 0;
    for (size_t i = 0; i < len; i++)
        diff |= a[i] ^ b[i];
    return (int)diff;
}