def _get_mem_hash(self, fin, end_offset, hash_list, **kwargs):
# kwargs
# diff: compare hash_list with self object
# free_pfn_dict: free memory physical frame number as a dictionary {'#':1, ... }
diff = kwargs.get("diff", None)
apply_free_memory = kwargs.get("apply_free_memory", True)
free_pfn_dict = kwargs.get("free_pfn_dict", None)
LOG.info("Get hash list of memory page")
prog_bar = AnimatedProgressBar(end=100, width=80, stdout=sys.stdout)
total_size = end_offset
ram_offset = 0
freed_page_counter = 0
base_hashlist_length = len(self.hash_list)
while total_size != ram_offset:
data = fin.read(Memory.RAM_PAGE_SIZE)
if not diff:
hash_list.append((ram_offset, len(data), sha256(data).digest()))
else:
# compare input with hash or corresponding base memory, save only when it is different
hash_list_index = ram_offset/Memory.RAM_PAGE_SIZE
if hash_list_index < base_hashlist_length:
self_hash_value = self.hash_list[hash_list_index][2]
else:
self_hash_value = None
if self_hash_value != sha256(data).digest():
is_free_memory = False
if (free_pfn_dict != None) and \
(free_pfn_dict.get(long(ram_offset/Memory.RAM_PAGE_SIZE), None) == 1):
is_free_memory = True
if is_free_memory and apply_free_memory:
# Do not compare. It is free memory
freed_page_counter += 1
else:
#get xdelta comparing self.raw
source_data = self.get_raw_data(ram_offset, len(data))
#save xdelta as DeltaItem only when it gives smaller
try:
if source_data == None:
raise IOError("launch memory snapshot is bigger than base vm")
patch = tool.diff_data(source_data, data, 2*len(source_data))
if len(patch) < len(data):
delta_item = DeltaItem(DeltaItem.DELTA_MEMORY,
ram_offset, len(data),
hash_value=sha256(data).digest(),
ref_id=DeltaItem.REF_XDELTA,
data_len=len(patch),
data=patch)
else:
raise IOError("xdelta3 patch is bigger than origianl")
except IOError as e:
#LOG.info("xdelta failed, so save it as raw (%s)" % str(e))
delta_item = DeltaItem(DeltaItem.DELTA_MEMORY,
ram_offset, len(data),
hash_value=sha256(data).digest(),
ref_id=DeltaItem.REF_RAW,
data_len=len(data),
data=data)
hash_list.append(delta_item)
# memory over-usage protection
if len(hash_list) > Memory.RAM_PAGE_SIZE*1000000: # 400MB for hashlist
raise MemoryError("possibly comparing with wrong base VM")
ram_offset += len(data)
# print progress bar for every 100 page
if (ram_offset % (Memory.RAM_PAGE_SIZE*100)) == 0:
prog_bar.set_percent(100.0*ram_offset/total_size)
prog_bar.show_progress()
prog_bar.finish()
return freed_page_counter
