Adding upstream version 115.7.0esr.upstream/115.7.0esrupstream

Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>

1 files changed, 174 insertions, 0 deletions

diff --git a/third_party/libwebrtc/build/extract_partition.py b/third_party/libwebrtc/build/extract_partition.py
new file mode 100755
index 0000000000..8b79a065d7
--- /dev/null
+++ b/third_party/libwebrtc/build/extract_partition.py
@@ -0,0 +1,174 @@
+#!/usr/bin/env python
+# Copyright 2019 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.
+"""Extracts an LLD partition from an ELF file."""
+
+import argparse
+import hashlib
+import math
+import os
+import struct
+import subprocess
+import sys
+import tempfile
+
+
+def _ComputeNewBuildId(old_build_id, file_path):
+  """
+    Computes the new build-id from old build-id and file_path.
+
+    Args:
+      old_build_id: Original build-id in bytearray.
+      file_path: Path to output ELF file.
+
+    Returns:
+      New build id with the same length as |old_build_id|.
+    """
+  m = hashlib.sha256()
+  m.update(old_build_id)
+  m.update(os.path.basename(file_path).encode('utf-8'))
+  hash_bytes = m.digest()
+  # In case build_id is longer than hash computed, repeat the hash
+  # to the desired length first.
+  id_size = len(old_build_id)
+  hash_size = len(hash_bytes)
+  return (hash_bytes * (id_size // hash_size + 1))[:id_size]
+
+
+def _ExtractPartition(objcopy, input_elf, output_elf, partition):
+  """
+  Extracts a partition from an ELF file.
+
+  For partitions other than main partition, we need to rewrite
+  the .note.gnu.build-id section so that the build-id remains
+  unique.
+
+  Note:
+  - `objcopy` does not modify build-id when partitioning the
+    combined ELF file by default.
+  - The new build-id is calculated as hash of original build-id
+    and partitioned ELF file name.
+
+  Args:
+    objcopy: Path to objcopy binary.
+    input_elf: Path to input ELF file.
+    output_elf: Path to output ELF file.
+    partition: Partition to extract from combined ELF file. None when
+      extracting main partition.
+  """
+  if not partition:  # main partition
+    # We do not overwrite build-id on main partition to allow the expected
+    # partition build ids to be synthesized given a libchrome.so binary,
+    # if necessary.
+    subprocess.check_call(
+        [objcopy, '--extract-main-partition', input_elf, output_elf])
+    return
+
+  # partitioned libs
+  build_id_section = '.note.gnu.build-id'
+
+  with tempfile.TemporaryDirectory() as tempdir:
+    temp_elf = os.path.join(tempdir, 'obj_without_id.so')
+    old_build_id_file = os.path.join(tempdir, 'old_build_id')
+    new_build_id_file = os.path.join(tempdir, 'new_build_id')
+
+    # Dump out build-id section and remove original build-id section from
+    # ELF file.
+    subprocess.check_call([
+        objcopy,
+        '--extract-partition',
+        partition,
+        # Note: Not using '--update-section' here as it is not supported
+        # by llvm-objcopy.
+        '--remove-section',
+        build_id_section,
+        '--dump-section',
+        '{}={}'.format(build_id_section, old_build_id_file),
+        input_elf,
+        temp_elf,
+    ])
+
+    with open(old_build_id_file, 'rb') as f:
+      note_content = f.read()
+
+    # .note section has following format according to <elf/external.h>
+    #   typedef struct {
+    #       unsigned char   namesz[4];  /* Size of entry's owner string */
+    #       unsigned char   descsz[4];  /* Size of the note descriptor */
+    #       unsigned char   type[4];    /* Interpretation of the descriptor */
+    #       char        name[1];        /* Start of the name+desc data */
+    #   } Elf_External_Note;
+    # `build-id` rewrite is only required on Android platform,
+    # where we have partitioned lib.
+    # Android platform uses little-endian.
+    # <: little-endian
+    # 4x: Skip 4 bytes
+    # L: unsigned long, 4 bytes
+    descsz, = struct.Struct('<4xL').unpack_from(note_content)
+    prefix = note_content[:-descsz]
+    build_id = note_content[-descsz:]
+
+    with open(new_build_id_file, 'wb') as f:
+      f.write(prefix + _ComputeNewBuildId(build_id, output_elf))
+
+    # Write back the new build-id section.
+    subprocess.check_call([
+        objcopy,
+        '--add-section',
+        '{}={}'.format(build_id_section, new_build_id_file),
+        # Add alloc section flag, or else the section will be removed by
+        # objcopy --strip-all when generating unstripped lib file.
+        '--set-section-flags',
+        '{}={}'.format(build_id_section, 'alloc'),
+        temp_elf,
+        output_elf,
+    ])
+
+
+def main():
+  parser = argparse.ArgumentParser(description=__doc__)
+  parser.add_argument(
+      '--partition',
+      help='Name of partition if not the main partition',
+      metavar='PART')
+  parser.add_argument(
+      '--objcopy',
+      required=True,
+      help='Path to llvm-objcopy binary',
+      metavar='FILE')
+  parser.add_argument(
+      '--unstripped-output',
+      required=True,
+      help='Unstripped output file',
+      metavar='FILE')
+  parser.add_argument(
+      '--stripped-output',
+      required=True,
+      help='Stripped output file',
+      metavar='FILE')
+  parser.add_argument('--dwp', help='Path to dwp binary', metavar='FILE')
+  parser.add_argument('input', help='Input file')
+  args = parser.parse_args()
+
+  _ExtractPartition(args.objcopy, args.input, args.unstripped_output,
+                    args.partition)
+  subprocess.check_call([
+      args.objcopy,
+      '--strip-all',
+      args.unstripped_output,
+      args.stripped_output,
+  ])
+
+  if args.dwp:
+    dwp_args = [
+        args.dwp, '-e', args.unstripped_output, '-o',
+        args.unstripped_output + '.dwp'
+    ]
+    # Suppress output here because it doesn't seem to be useful. The most
+    # common error is a segfault, which will happen if files are missing.
+    subprocess.check_output(dwp_args, stderr=subprocess.STDOUT)
+
+
+if __name__ == '__main__':
+  sys.exit(main())