WEBDIENSTE/volatility3
1
0
Fork 0
mirror of https://github.com/volatilityfoundation/volatility3.git synced 2026-09-13 13:17:38 +02:00
Code Issues Packages Projects Releases Wiki Activity

Reuse the cache if we're within the same ResourceAccessor.

Browse Source 
This effectively means that the FileTranslationLayer will reuse the
cached file even with multiple opens, but rerunning python, or starting
a new context (with a new FileTranslationLayer but on the same URL) will
cause a redownload whether necessary or not.  This ensures that running
volatility as an engine (inside a long lived python session) will not
prevent a file being checked again later.

Other caching mechanisms (such as last-modified) should be used to
determine if the cached file is still valid.

Note this may cause issues if plugins run concurrently.
This commit is contained in:
Mike Auty
2017-11-25 14:00:16 +00:00
parent 7a40d8128c
commit 0ad6294662
1 changed files with 21 additions and 10 deletions
Download Patch File Download Diff File Expand all files Collapse all files
volatility/framework/layers/__init__.py
+21 -10
View File
@@ -40,6 +40,7 @@ class ResourceAccessor(object):
"""
self._progress_callback = progress_callback
self._context = context
self._cached_files = []
self._handlers = list(framework.class_subclasses(request.BaseHandler))
vollog.log(constants.LOGLEVEL_VVV,
"Available URL handlers: {}".format(", ".join([x.__name__ for x in self._handlers])))
@@ -60,16 +61,26 @@ class ResourceAccessor(object):
block_size = 1028 * 8
temp_filename = os.path.join(constants.CACHE_PATH,
"data_" + hashlib.sha512(bytes(url, 'latin-1')).hexdigest())
cache_file = open(temp_filename, "wb")
while True:
block = fp.read(block_size)
if not block:
break
cache_file.write(block)
if self._progress_callback:
# TODO: Figure out the size and therefore percentage complete
self._progress_callback(0, "Reading file {}".format(url))
cache_file.close()
if not temp_filename in self._cached_files or not os.path.exists(temp_filename):
vollog.info("Caching file at: {}".format(temp_filename))
content_length = fp.info().get('Content-Length', -1)
cache_file = open(temp_filename, "wb")
count = 0
while True:
block = fp.read(block_size)
count += len(block)
if not block:
break
if self._progress_callback:
self._progress_callback(count / max(count, int(content_length)),
"Reading file {}".format(url))
cache_file.write(block)
cache_file.close()
# Globally stash the file as cached this python session
self._cached_files += [temp_filename]
# Re-open the cache with a different mode
curfile = open(temp_filename, mode = "rb")