1 files changed, 98 insertions, 0 deletions
diff --git a/third_party/libwebrtc/build/win/reorder-imports.py b/third_party/libwebrtc/build/win/reorder-imports.py
new file mode 100755
index 0000000000..0995ae0058
--- /dev/null
+++ b/third_party/libwebrtc/build/win/reorder-imports.py
@@ -0,0 +1,98 @@
+#!/usr/bin/env python
+# Copyright 2014 The Chromium Authors. All rights reserved.
+# Use of this source code is governed by a BSD-style license that can be
+# found in the LICENSE file.
+
+import glob
+import optparse
+import os
+import shutil
+import subprocess
+import sys
+
+sys.path.insert(
+    0,
+    os.path.join(os.path.dirname(__file__), '..', '..', 'third_party',
+                 'pefile_py3'))
+import pefile
+
+def reorder_imports(input_dir, output_dir, architecture):
+  """Swap chrome_elf.dll to be the first import of chrome.exe.
+  Also copy over any related files that might be needed
+  (pdbs, manifests etc.).
+  """
+  # TODO(thakis): See if there is a reliable way to write the
+  # correct executable in the first place, so that this script
+  # only needs to verify that and not write a whole new exe.
+
+  input_image = os.path.join(input_dir, 'chrome.exe')
+  output_image = os.path.join(output_dir, 'chrome.exe')
+
+  # pefile mmap()s the whole executable, and then parses parts of
+  # it into python data structures for ease of processing.
+  # To write the file again, only the mmap'd data is written back,
+  # so modifying the parsed python objects generally has no effect.
+  # However, parsed raw data ends up in pe.Structure instances,
+  # and these all get serialized back when the file gets written.
+  # So things that are in a Structure must have their data set
+  # through the Structure, while other data must bet set through
+  # the set_bytes_*() methods.
+  pe = pefile.PE(input_image, fast_load=True)
+  if architecture == 'x64' or architecture == 'arm64':
+    assert pe.PE_TYPE == pefile.OPTIONAL_HEADER_MAGIC_PE_PLUS
+  else:
+    assert pe.PE_TYPE == pefile.OPTIONAL_HEADER_MAGIC_PE
+
+  pe.parse_data_directories(directories=[
+      pefile.DIRECTORY_ENTRY['IMAGE_DIRECTORY_ENTRY_IMPORT']])
+
+  found_elf = False
+  for i, peimport in enumerate(pe.DIRECTORY_ENTRY_IMPORT):
+    if peimport.dll.lower() == b'chrome_elf.dll':
+      assert not found_elf, 'only one chrome_elf.dll import expected'
+      found_elf = True
+      if i > 0:
+        swap = pe.DIRECTORY_ENTRY_IMPORT[0]
+
+        # Morally we want to swap peimport.struct and swap.struct here,
+        # but the pe module doesn't expose a public method on Structure
+        # to get all data of a Structure without explicitly listing all
+        # field names.
+        # NB: OriginalFirstThunk and Characteristics are an union both at
+        # offset 0, handling just one of them is enough.
+        peimport.struct.OriginalFirstThunk, swap.struct.OriginalFirstThunk = \
+            swap.struct.OriginalFirstThunk, peimport.struct.OriginalFirstThunk
+        peimport.struct.TimeDateStamp, swap.struct.TimeDateStamp = \
+            swap.struct.TimeDateStamp, peimport.struct.TimeDateStamp
+        peimport.struct.ForwarderChain, swap.struct.ForwarderChain = \
+            swap.struct.ForwarderChain, peimport.struct.ForwarderChain
+        peimport.struct.Name, swap.struct.Name = \
+            swap.struct.Name, peimport.struct.Name
+        peimport.struct.FirstThunk, swap.struct.FirstThunk = \
+            swap.struct.FirstThunk, peimport.struct.FirstThunk
+  assert found_elf, 'chrome_elf.dll import not found'
+
+  pe.write(filename=output_image)
+
+  for fname in glob.iglob(os.path.join(input_dir, 'chrome.exe.*')):
+    shutil.copy(fname, os.path.join(output_dir, os.path.basename(fname)))
+  return 0
+
+
+def main(argv):
+  usage = 'reorder_imports.py -i <input_dir> -o <output_dir> -a <target_arch>'
+  parser = optparse.OptionParser(usage=usage)
+  parser.add_option('-i', '--input', help='reorder chrome.exe in DIR',
+      metavar='DIR')
+  parser.add_option('-o', '--output', help='write new chrome.exe to DIR',
+      metavar='DIR')
+  parser.add_option('-a', '--arch', help='architecture of build (optional)',
+      default='ia32')
+  opts, args = parser.parse_args()
+
+  if not opts.input or not opts.output:
+    parser.error('Please provide and input and output directory')
+  return reorder_imports(opts.input, opts.output, opts.arch)
+
+if __name__ == "__main__":
+  sys.exit(main(sys.argv[1:]))