random: add a mutex to guard random.Random

Modules/_randommodule.c

@@ -104,6 +104,7 @@ static struct PyModuleDef _randommodule;
 
 typedef struct {
  PyObject_HEAD
+ _PyMutex mutex;
  int index;
  uint32_t state[N];
 } RandomObject;
@@ -177,7 +178,9 @@ static PyObject *
 _random_Random_random_impl(RandomObject *self)
 /*[clinic end generated code: output=117ff99ee53d755c input=afb2a59cbbb00349]*/
 {
+ _PyMutex_lock(&self->mutex);
  uint32_t a=genrand_uint32(self)>>5, b=genrand_uint32(self)>>6;
+ _PyMutex_unlock(&self->mutex);
  return PyFloat_FromDouble((a*67108864.0+b)*(1.0/9007199254740992.0));
 }
 
@@ -211,6 +214,7 @@ init_by_array(RandomObject *self, uint32_t init_key[], size_t key_length)
  size_t i, j, k; /* was signed in the original code. RDH 12/16/2002 */
  uint32_t *mt;
 
+ _PyMutex_lock(&self->mutex);
  mt = self->state;
  init_genrand(self, 19650218U);
  i=1; j=0;
@@ -230,7 +234,7 @@ init_by_array(RandomObject *self, uint32_t init_key[], size_t key_length)
  }
 
  mt[0] = 0x80000000U; /* MSB is 1; assuring non-zero initial array */
-}
+ _PyMutex_unlock(&self->mutex);}
 
 /*
  * The rest is Python-specific code, neither part of, nor derived from, the
@@ -398,6 +402,8 @@ _random_Random_getstate_impl(RandomObject *self)
  state = PyTuple_New(N+1);
  if (state == NULL)
  return NULL;
+
+ _PyMutex_lock(&self->mutex);
  for (i=0; i<N ; i++) {
  element = PyLong_FromUnsignedLong(self->state[i]);
  if (element == NULL)
@@ -408,9 +414,11 @@ _random_Random_getstate_impl(RandomObject *self)
  if (element == NULL)
  goto Fail;
  PyTuple_SET_ITEM(state, i, element);
+ _PyMutex_unlock(&self->mutex);
  return state;
 
 Fail:
+ _PyMutex_unlock(&self->mutex);
  Py_DECREF(state);
  return NULL;
 }
@@ -460,9 +468,12 @@ _random_Random_setstate(RandomObject *self, PyObject *state)
  PyErr_SetString(PyExc_ValueError, "invalid state");
  return NULL;
  }
+
+ _PyMutex_lock(&self->mutex);
  self->index = (int)index;
  for (i = 0; i < N; i++)
  self->state[i] = new_state[i];
+ _PyMutex_unlock(&self->mutex);
 
  Py_RETURN_NONE;
 }
@@ -496,8 +507,13 @@ _random_Random_getrandbits_impl(RandomObject *self, int k)
  if (k == 0)
  return PyLong_FromLong(0);
 
- if (k <= 32) /* Fast path */
- return PyLong_FromUnsignedLong(genrand_uint32(self) >> (32 - k));
+ if (k <= 32) {
+ /* Fast path */
+ _PyMutex_lock(&self->mutex);
+ r = genrand_uint32(self);
+ _PyMutex_unlock(&self->mutex);
+ return PyLong_FromUnsignedLong(r >> (32 - k));
+ }
 
  words = (k - 1) / 32 + 1;
  wordarray = (uint32_t *)PyMem_Malloc(words * 4);
@@ -508,6 +524,7 @@ _random_Random_getrandbits_impl(RandomObject *self, int k)
 
  /* Fill-out bits of long integer, by 32-bit words, from least significant
  to most significant. */
+ _PyMutex_lock(&self->mutex);
 #if PY_LITTLE_ENDIAN
  for (i = 0; i < words; i++, k -= 32)
 #else
@@ -519,6 +536,7 @@ _random_Random_getrandbits_impl(RandomObject *self, int k)
  r >>= (32 - k); /* Drop least significant bits */
  wordarray[i] = r;
  }
+ _PyMutex_unlock(&self->mutex);
 
  result = _PyLong_FromByteArray((unsigned char *)wordarray, words * 4,
  PY_LITTLE_ENDIAN, 0 /* unsigned */);