lldb/test/Shell/Register/Core/Inputs/strip-coredump.py

   1 #!/usr/bin/env python
   2 # Strip unnecessary data from a core dump to reduce its size.
   3 #
   4 # Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
   5 # See https://llvm.org/LICENSE.txt for license information.
   6 # SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
   7
   8 import argparse
   9 import os.path
  10 import sys
  11 import tempfile
  12
  13 from elftools.elf.elffile import ELFFile
  14
  15
  16 def strip_non_notes(elf, inf, outf):
  17     next_segment_offset = min(x.header.p_offset for x in elf.iter_segments())
  18     copy_segments = filter(lambda x: x.header.p_type == "PT_NOTE", elf.iter_segments())
  19
  20     # first copy the headers
  21     inf.seek(0)
  22     outf.write(inf.read(next_segment_offset))
  23
  24     for seg in copy_segments:
  25         assert seg.header.p_filesz > 0
  26
  27         inf.seek(seg.header.p_offset)
  28         # fill the area between last write and new offset with zeros
  29         outf.seek(seg.header.p_offset)
  30
  31         # now copy the segment
  32         outf.write(inf.read(seg.header.p_filesz))
  33
  34
  35 def main():
  36     argp = argparse.ArgumentParser()
  37     action = argp.add_mutually_exclusive_group(required=True)
  38     action.add_argument(
  39         "--strip-non-notes",
  40         action="store_const",
  41         const=strip_non_notes,
  42         dest="action",
  43         help="Strip all segments except for notes",
  44     )
  45     argp.add_argument("elf", help="ELF file to strip (in place)", nargs="+")
  46     args = argp.parse_args()
  47
  48     for path in args.elf:
  49         with open(path, "rb") as f:
  50             elf = ELFFile(f)
  51             # we do not support copying the section table now
  52             assert elf.num_sections() == 0
  53
  54             tmpf = tempfile.NamedTemporaryFile(dir=os.path.dirname(path), delete=False)
  55             try:
  56                 args.action(elf, f, tmpf)
  57             except:
  58                 os.unlink(tmpf.name)
  59                 raise
  60             else:
  61                 os.rename(tmpf.name, path)
  62
  63     return 0
  64
  65
  66 if __name__ == "__main__":
  67     sys.exit(main())