unix,windows: Factor out code that generates random bytes to a new func.

Signed-off-by: Damien George <damien@micropython.org>

ports/unix/moduos.c

@@ -25,25 +25,12 @@
  * THE SOFTWARE.
  */
 
-#include <fcntl.h>
 #include <stdlib.h>
 #include <string.h>
 
 #include "py/runtime.h"
 #include "py/mphal.h"
 
-#if defined(__GLIBC__) && defined(__GLIBC_PREREQ)
-#if __GLIBC_PREREQ(2, 25)
-#include <sys/random.h>
-#define _HAVE_GETRANDOM
-#endif
-#endif
-
-#if _WIN32
-#include <windows.h>
-#include <bcrypt.h>
-#endif
-
 STATIC mp_obj_t mp_uos_getenv(mp_obj_t var_in) {
     const char *s = getenv(mp_obj_str_get_str(var_in));
     if (s == NULL) {
@@ -105,21 +92,7 @@ STATIC mp_obj_t mp_uos_urandom(mp_obj_t num) {
     mp_int_t n = mp_obj_get_int(num);
     vstr_t vstr;
     vstr_init_len(&vstr, n);
-    #if _WIN32
+    mp_hal_get_random(n, vstr.buf);
-    NTSTATUS result = BCryptGenRandom(NULL, (unsigned char *)vstr.buf, n, BCRYPT_USE_SYSTEM_PREFERRED_RNG);
-    if (!BCRYPT_SUCCESS(result)) {
-        mp_raise_OSError(errno);
-    }
-    #else
-    #ifdef _HAVE_GETRANDOM
-    RAISE_ERRNO(getrandom(vstr.buf, n, 0), errno);
-    #else
-    int fd = open("/dev/urandom", O_RDONLY);
-    RAISE_ERRNO(fd, errno);
-    RAISE_ERRNO(read(fd, vstr.buf, n), errno);
-    close(fd);
-    #endif
-    #endif
     return mp_obj_new_str_from_vstr(&mp_type_bytes, &vstr);
 }
 STATIC MP_DEFINE_CONST_FUN_OBJ_1(mp_uos_urandom_obj, mp_uos_urandom);

ports/unix/mphalport.h

@@ -91,6 +91,8 @@ static inline void mp_hal_delay_us(mp_uint_t us) {
     { if (err_flag == -1) \
       { mp_raise_OSError(error_val); } }
 
+void mp_hal_get_random(size_t n, void *buf);
+
 #if MICROPY_PY_BLUETOOTH
 enum {
     MP_HAL_MAC_BDADDR,

ports/unix/unix_mphal.c

@@ -29,12 +29,20 @@
 #include <string.h>
 #include <time.h>
 #include <sys/time.h>
+#include <fcntl.h>
 
 #include "py/mphal.h"
 #include "py/mpthread.h"
 #include "py/runtime.h"
 #include "extmod/misc.h"
 
+#if defined(__GLIBC__) && defined(__GLIBC_PREREQ)
+#if __GLIBC_PREREQ(2, 25)
+#include <sys/random.h>
+#define _HAVE_GETRANDOM
+#endif
+#endif
+
 #ifndef _WIN32
 #include <signal.h>
 
@@ -234,3 +242,14 @@ void mp_hal_delay_ms(mp_uint_t ms) {
     usleep(ms * 1000);
     #endif
 }
+
+void mp_hal_get_random(size_t n, void *buf) {
+    #ifdef _HAVE_GETRANDOM
+    RAISE_ERRNO(getrandom(buf, n, 0), errno);
+    #else
+    int fd = open("/dev/urandom", O_RDONLY);
+    RAISE_ERRNO(fd, errno);
+    RAISE_ERRNO(read(fd, buf, n), errno);
+    close(fd);
+    #endif
+}

ports/windows/windows_mphal.c

@@ -32,6 +32,7 @@
 #include <sys/time.h>
 #include <windows.h>
 #include <unistd.h>
+#include <bcrypt.h>
 
 HANDLE std_in = NULL;
 HANDLE con_out = NULL;
@@ -286,3 +287,10 @@ void mp_hal_delay_ms(mp_uint_t ms) {
     msec_sleep((double)ms);
     #endif
 }
+
+void mp_hal_get_random(size_t n, void *buf) {
+    NTSTATUS result = BCryptGenRandom(NULL, (unsigned char *)buf, n, BCRYPT_USE_SYSTEM_PREFERRED_RNG);
+    if (!BCRYPT_SUCCESS(result)) {
+        mp_raise_OSError(errno);
+    }
+}