Function GetDevURandom

src/random.cpp:255–271

Fallback: get 32 bytes of system entropy from /dev/urandom. The most * compatible way to get cryptographic randomness on UNIX-ish platforms. */

 * compatible way to get cryptographic randomness on UNIX-ish platforms.
 */
static void GetDevURandom(unsigned char *ent32)
{
    int f = open("/dev/urandom", O_RDONLY);
    if (f == -1) {
        RandFailure();
    }
    int have = 0;
    do {
        ssize_t n = read(f, ent32 + have, NUM_OS_RANDOM_BYTES - have);
        if (n <= 0 || n + have > NUM_OS_RANDOM_BYTES) {
            close(f);
            RandFailure();
        }
        have += n;
    } while (have < NUM_OS_RANDOM_BYTES);
    close(f);
}
#endif

/** Get 32 bytes of system entropy. */