bcc: Fix hash table batch operation attribute error

Some tools get errors when kernel supports hash table batch operations
and hash key or value is integer type.

  AttributeError: 'long' object has no attribute 'value'

It's caused by ctypes library from python. For example, when hash tables
try to do batch lookup, it will alloc arrays to stores keys and values
first. If it is a ctypes integer type, after expanding to array, type of
element will be changed to python 'long' or 'int'. When trying to access
its value attribute, error message is generated.

  >>> from ctypes import *
  >>> a = c_uint(10)
  >>> type(a)
  <class 'ctypes.c_uint'>
  >>> a.value
  10
  >>> b = (c_uint * 1)(10)
  >>> type(b)
  <class '__main__.c_uint_Array_1'>
  >>> b[0].value
  Traceback (most recent call last):
    File "<stdin>", line 1, in <module>
  AttributeError: 'int' object has no attribute 'value'

Turn back to original ctypes type can avoid this error.

Change-Id: Ia8598510e79ec9a3b73de3e343b9781c97ead894
Signed-off-by: mickey_zhu <[email protected]>

src/python/bcc/table.py

@@ -609,7 +609,13 @@ def _items_lookup_and_optionally_delete_batch(self, delete=True):
  break
 
  for i in range(0, total):
- yield (ct_keys[i], ct_values[i])
+ k = ct_keys[i]
+ v = ct_values[i]
+ if not isinstance(k, ct.Structure):
+ k = self.Key(k)
+ if not isinstance(v, ct.Structure):
+ v = self.Leaf(v)
+ yield (k, v)
 
  def zero(self):
  # Even though this is not very efficient, we grab the entire list of

tests/python/test_map_batch_ops.py

@@ -31,9 +31,9 @@ def prepare_keys_subset(self, hmap, count=None):
  count = self.SUBSET_SIZE
  keys = (hmap.Key * count)()
  i = 0
- for k, _ in sorted(hmap.items_lookup_batch()):
+ for k, _ in sorted(hmap.items_lookup_batch(), key=lambda k:k[0].value):
  if i < count:
- keys[i] = k
+ keys[i] = k.value
  i += 1
  else:
  break
@@ -45,19 +45,19 @@ def prepare_values_subset(self, hmap, count=None):
  count = self.SUBSET_SIZE
  values = (hmap.Leaf * count)()
  i = 0
- for _, v in sorted(hmap.items_lookup_batch()):
+ for _, v in sorted(hmap.items_lookup_batch(), key=lambda k:k[0].value):
  if i < count:
- values[i] = v*v
+ values[i] = v.value * v.value
  i += 1
  else:
  break
  return values
 
  def check_hashmap_values(self, it):
  i = 0
- for k, v in sorted(it):
- self.assertEqual(k, i)
- self.assertEqual(v, i)
+ for k, v in sorted(it, key=lambda kv:kv[0].value):
+ self.assertEqual(k.value, i)
+ self.assertEqual(v.value, i)
  i += 1
  return i
 
@@ -129,12 +129,15 @@ def test_update_batch_subset(self):
  # the first self.SUBSET_SIZE keys follow this rule value = keys * keys
  # the remaning keys follow this rule : value = keys
  i = 0
- for k, v in sorted(hmap.items_lookup_batch()):
+ for k, v in sorted(hmap.items_lookup_batch(),
+ key=lambda kv:kv[0].value):
  if i < self.SUBSET_SIZE:
- self.assertEqual(v, k*k) # values are the square of the keys
+ # values are the square of the keys
+ self.assertEqual(v.value, k.value * k.value)
  i += 1
  else:
- self.assertEqual(v, k) # values = keys
+ # values = keys
+ self.assertEqual(v.value, k.value)
 
  self.assertEqual(i, self.SUBSET_SIZE)