1 files changed, 232 insertions, 0 deletions
diff --git a/tools/pylibdexfile.py b/tools/pylibdexfile.py
new file mode 100644
index 0000000000..30c0b268aa
--- /dev/null
+++ b/tools/pylibdexfile.py
@@ -0,0 +1,232 @@
+#!/usr/bin/python3
+#
+# Copyright (C) 2021 The Android Open Source Project
+#
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+#      http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+
+#
+# This script can get info out of dexfiles using libdexfile_external
+#
+
+from abc import ABC
+from ctypes import *
+import os.path
+import functools
+import zipfile
+
+libdexfile_external = CDLL(
+    os.path.expandvars("$ANDROID_HOST_OUT/lib64/libdexfile_external.so"))
+
+DexFileStr = c_void_p
+ExtDexFile = c_void_p
+
+
+class ExtMethodInfo(Structure):
+  """Output format for MethodInfo"""
+  _fields_ = [("offset", c_int32), ("len", c_int32), ("name", DexFileStr)]
+
+
+AllMethodsCallback = CFUNCTYPE(c_int, POINTER(ExtMethodInfo), c_void_p)
+libdexfile_external.ExtDexFileOpenFromFd.argtypes = [
+    c_int, c_size_t, c_char_p,
+    POINTER(DexFileStr),
+    POINTER(ExtDexFile)
+]
+libdexfile_external.ExtDexFileOpenFromFd.restype = c_int
+libdexfile_external.ExtDexFileOpenFromMemory.argtypes = [
+    c_void_p,
+    POINTER(c_size_t), c_char_p,
+    POINTER(DexFileStr),
+    POINTER(ExtDexFile)
+]
+libdexfile_external.ExtDexFileOpenFromMemory.restype = c_int
+libdexfile_external.ExtDexFileFree.argtypes = [ExtDexFile]
+libdexfile_external.ExtDexFileGetAllMethodInfos.argtypes = [
+    ExtDexFile, c_int, AllMethodsCallback, c_void_p
+]
+libdexfile_external.ExtDexFileGetString.argtypes = [
+    DexFileStr, POINTER(c_size_t)
+]
+libdexfile_external.ExtDexFileGetString.restype = c_char_p
+libdexfile_external.ExtDexFileFreeString.argtypes = [DexFileStr]
+
+
+class DexClass(object):
+  """Accessor for DexClass Data"""
+
+  def __init__(self, name):
+    self.name = name.strip()
+    self.arrays = name.count("[")
+    self.base_name = self.name if self.arrays == 0 else self.name[:-(
+        self.arrays * 2)]
+
+  def __repr__(self):
+    return self.name
+
+  @functools.cached_property
+  def descriptor(self):
+    """The name as a descriptor"""
+    if self.base_name == "int":
+      return "[" * self.arrays + "I"
+    elif self.base_name == "short":
+      return "[" * self.arrays + "S"
+    elif self.base_name == "long":
+      return "[" * self.arrays + "J"
+    elif self.base_name == "char":
+      return "[" * self.arrays + "C"
+    elif self.base_name == "boolean":
+      return "[" * self.arrays + "Z"
+    elif self.base_name == "byte":
+      return "[" * self.arrays + "B"
+    elif self.base_name == "float":
+      return "[" * self.arrays + "F"
+    elif self.base_name == "double":
+      return "[" * self.arrays + "D"
+    elif self.base_name == "void":
+      return "[" * self.arrays + "V"
+    else:
+      return "[" * self.arrays + "L{};".format("/".join(
+          self.base_name.split(".")))
+
+
+class Method(object):
+  """Method info wrapper"""
+
+  def __init__(self, mi):
+    self.offset = mi.offset
+    self.len = mi.len
+    self.name = libdexfile_external.ExtDexFileGetString(
+        mi.name, byref(c_size_t(0))).decode("utf-8")
+    libdexfile_external.ExtDexFileFreeString(mi.name)
+
+  def __repr__(self):
+    return "(" + self.name + ")"
+
+  @functools.cached_property
+  def descriptor(self):
+    """name as a descriptor"""
+    ret = DexClass(self.name.split(" ")[0])
+    non_ret = self.name[len(ret.name) + 1:]
+    arg_str = non_ret[non_ret.find("(") + 1:-1]
+    args = [] if arg_str == "" else map(
+        lambda a: DexClass(a.strip()).descriptor, arg_str.split(","))
+    class_and_meth = non_ret[0:non_ret.find("(")]
+    class_only = DexClass(class_and_meth[0:class_and_meth.rfind(".")])
+    meth = class_and_meth[class_and_meth.rfind(".") + 1:]
+    return "{cls}->{meth}({args}){ret}".format(
+        cls=class_only.descriptor,
+        meth=meth,
+        args="".join(args),
+        ret=ret.descriptor)
+
+  @functools.cached_property
+  def name_only(self):
+    """name without the return-type or arguments in java format"""
+    ret = DexClass(self.name.split(" ")[0])
+    non_ret = self.name[len(ret.name) + 1:]
+    class_and_meth = non_ret[0:non_ret.find("(")]
+    return class_and_meth
+
+  @functools.cached_property
+  def klass(self):
+    """declaring DexClass."""
+    ret = DexClass(self.name.split(" ")[0])
+    non_ret = self.name[len(ret.name) + 1:]
+    class_and_meth = non_ret[0:non_ret.find("(")]
+    return DexClass(class_and_meth[0:class_and_meth.rfind(".")])
+
+
+class BaseDexFile(ABC):
+  """DexFile base class"""
+
+  def __init__(self):
+    self.ext_dex_file_ = None
+    return
+
+  @functools.cached_property
+  def methods(self):
+    """Methods in the dex-file"""
+    meths = []
+
+    @AllMethodsCallback
+    def my_cb(info, _):
+      """Callback visitor for method infos"""
+      meths.append(Method(info[0]))
+      return 0
+
+    libdexfile_external.ExtDexFileGetAllMethodInfos(self.ext_dex_file_,
+                                                    c_int(1), my_cb, c_void_p())
+    return meths
+
+
+class FdDexFile(BaseDexFile):
+  """DexFile using an opened file-descriptor"""
+
+  def __init__(self, fd, loc):
+    super().__init__()
+    res_fle_ptr = pointer(c_void_p())
+    err_ptr = pointer(c_void_p())
+    res = libdexfile_external.ExtDexFileOpenFromFd(
+        c_int(fd), 0, create_string_buffer(bytes(loc, "utf-8")), err_ptr,
+        res_fle_ptr)
+    if res == 0:
+      err = libdexfile_external.ExtDexFileGetString(err_ptr.contents,
+                                                    byref(c_size_t()))
+      out = Exception("Failed to open file: {}. Error was: {}".format(loc, err))
+      libdexfile_external.ExtDexFileFreeString(err_ptr.contents)
+      raise out
+    self.ext_dex_file_ = res_fle_ptr.contents
+
+
+class FileDexFile(FdDexFile):
+  """DexFile using a file"""
+
+  def __init__(self, file, loc):
+    if type(file) == str:
+      self.file = open(file, "rb")
+    else:
+      self.file = file
+    super().__init__(self.file.fileno(), loc)
+
+
+class MemDexFile(BaseDexFile):
+  """DexFile using memory"""
+
+  def __init__(self, dat, loc):
+    assert type(dat) == bytes
+    super().__init__()
+    # Don't want GC to screw us over.
+    self.mem_ref = (c_byte * len(dat)).from_buffer_copy(dat)
+    res_fle_ptr = pointer(c_void_p())
+    err_ptr = pointer(c_void_p())
+    res = libdexfile_external.ExtDexFileOpenFromMemory(
+        self.mem_ref, byref(c_size_t(len(dat))),
+        create_string_buffer(bytes(loc, "utf-8")), err_ptr, res_fle_ptr)
+    if res == 0:
+      err = libdexfile_external.ExtDexFileGetString(err_ptr.contents,
+                                                    byref(c_size_t()))
+      out = Exception("Failed to open file: {}. Error was: {}".format(loc, err))
+      libdexfile_external.ExtDexFileFreeString(err_ptr.contents)
+      raise out
+    self.ext_dex_file_ = res_fle_ptr.contents
+
+
+def OpenJar(fle):
+  """Opens all classes[0-9]*.dex files in a zip archive"""
+  res = []
+  with zipfile.ZipFile(fle) as zf:
+    for f in zf.namelist():
+      if f.endswith(".dex") and f.startswith("classes"):
+        res.append(
+            MemDexFile(zf.read(f), "classes" if type(fle) != str else fle))
+  return res