diff options
Diffstat (limited to 'byterun/sys.c')
| -rw-r--r-- | byterun/sys.c | 40 |
1 files changed, 31 insertions, 9 deletions
diff --git a/byterun/sys.c b/byterun/sys.c index dcc290756..ce364d8c1 100644 --- a/byterun/sys.c +++ b/byterun/sys.c @@ -291,27 +291,49 @@ CAMLprim value caml_sys_time(value unit) } #ifdef _WIN32 -extern intnat caml_win32_random_seed (void); +extern int caml_win32_random_seed (intnat data[16]); #endif CAMLprim value caml_sys_random_seed (value unit) { + intnat data[16]; + int n, i; + value res; #ifdef _WIN32 - return Val_long(caml_win32_random_seed()); + n = caml_win32_random_seed(data); #else - intnat seed; + 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); - seed = tv.tv_sec ^ tv.tv_usec; + struct timeval tv; + gettimeofday(&tv, NULL); + data[n++] = tv.tv_usec; + data[n++] = tv.tv_sec; #else - seed = time (NULL); + data[n++] = time(NULL); #endif #ifdef HAS_UNISTD - seed ^= (getppid() << 16) ^ getpid(); + data[n++] = getpid(); + data[n++] = getppid(); #endif - return Val_long(seed); + } #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; } CAMLprim value caml_sys_get_config(value unit) |