fix unpacking bins tuples (#563)

* fix unpacking bins tuples

* pop type

pwndbg/commands/heap.py

@@ -37,16 +37,17 @@ def format_bin(bins, verbose=False, offset=None):
         offset = main_heap.chunk_key_offset('fd')
 
     result = []
+    bins_type = bins.pop('type')
+
     for size in bins:
         b = bins[size]
-
         count, is_chain_corrupted = None, False
 
         # fastbins consists of only single linked list
-        if len(b) == 1:  # fastbin:
+        if bins_type == 'fastbins':
             chain_fd = b
         # tcachebins consists of single linked list and entries count
-        elif len(b) == 2:  # tcachebin:
+        elif bins_type == 'tcachebins':
             chain_fd, count = b
         # normal bins consists of double linked list and may be corrupted (we can detect corruption)
         else:  # normal bin

pwndbg/heap/ptmalloc.py

@@ -434,6 +434,7 @@ class Heap(pwndbg.heap.heap.BaseHeap):
 
             result[size] = chain
 
+        result['type'] = 'fastbins'
         return result
 
 
@@ -461,6 +462,7 @@ class Heap(pwndbg.heap.heap.BaseHeap):
 
             result[size] = (chain, count)
 
+        result['type'] = 'tcachebins'
         return result
 
 
@@ -520,6 +522,7 @@ class Heap(pwndbg.heap.heap.BaseHeap):
 
         result['all'] = chain
 
+        result['type'] = 'unsortedbin'
         return result
 
 
@@ -537,6 +540,7 @@ class Heap(pwndbg.heap.heap.BaseHeap):
 
             result[size] = chain
 
+        result['type'] = 'smallbins'
         return result
 
 
@@ -554,6 +558,7 @@ class Heap(pwndbg.heap.heap.BaseHeap):
 
             result[size] = chain
 
+        result['type'] = 'largebins'
         return result