CAMLprim value caml_sys_random_seed (value unit)
{
#ifdef _WIN32
return Val_long(caml_win32_random_seed());
#else
intnat seed;
#ifdef HAS_GETTIMEOFDAY
struct timeval tv;
gettimeofday(&tv, NULL);
seed = tv.tv_sec ^ tv.tv_usec;
#else
seed = time (NULL);
#endif
#ifdef HAS_UNISTD
seed ^= (getppid() << 16) ^ getpid();
#endif
return Val_long(seed);
#endif
}
CAMLprim value caml_sys_random_seed (value unit)
{
intnat data[16];
int n, i;
value res;
#ifdef _WIN32
n = caml_win32_random_seed(data);
#else
int fd;
n = 0;
/* Try /dev/urandom first */
fd = open("/dev/urandom", O_RDONLY, 0);
if (fd != -1) {
unsigned char buffer[12];
int nread = read(fd, buffer, 12);
close(fd);
while (nread > 0) data[n++] = buffer[--nread];
}
/* If the read from /dev/urandom fully succeeded, we now have 96 bits
of good random data and can stop here. Otherwise, complement
whatever we got (probably nothing) with some not-very-random data. */
if (n < 12) {
#ifdef HAS_GETTIMEOFDAY
struct timeval tv;
gettimeofday(&tv, NULL);
data[n++] = tv.tv_usec;
data[n++] = tv.tv_sec;
#else
data[n++] = time(NULL);
#endif
#ifdef HAS_UNISTD
data[n++] = getpid();
data[n++] = getppid();
#endif
}
#endif
/* Convert to an OCaml array of ints */
res = caml_alloc_small(n, 0);
for (i = 0; i < n; i++) Field(res, i) = Val_long(data[i]);
return res;
}
