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#------------------------------------------------------------------------------
# elftools tests
#
# Gabriele Digregorio - Io_no
# This code is in the public domain
#------------------------------------------------------------------------------
from elftools.elf.elffile import ELFFile
import unittest
class TestDebuglink(unittest.TestCase):
""" This test verifies that the .gnu_debuglink section is followed and parsed correctly.
The test file contains a .gnu_debuglink section that points to a debug file
containing DWARF info.
We verify that the subprograms are correctly retrieved from the debug file.
"""
def stream_loader(self, external_filename: str) -> 'IO[bytes]':
"""
This function takes an external filename to load a supplementary object file,
and returns a stream suitable for creating a new ELFFile.
Args:
external_filename (str): The relative file path to load.
Returns:
stream (IO[bytes]): A stream suitable for creating a new ELFFile.
"""
self.assertEqual(external_filename, b'debuglink.debug')
stream = open(b'test/testfiles_for_unittests/' + external_filename, 'rb')
return stream
def subprograms_from_debuglink(self, elf: ELFFile) -> dict[str, (int, int)]:
"""Returns a dictionary containing the subprograms of the specified ELF file from the linked
debug file.
Args:
elf (ELFFile): The ELF file.
Returns:
dict: A dictionary containing the subprograms of the specified ELF file.
"""
subprograms = {}
# Retrieve the subprograms from the DWARF info
dwarf_info = elf.get_dwarf_info(follow_links=True, relocate_dwarf_sections=True)
if dwarf_info:
for CU in dwarf_info.iter_CUs():
for DIE in CU.iter_DIEs():
if DIE.tag == 'DW_TAG_subprogram':
attributes = DIE.attributes
lowpc_attr = attributes.get('DW_AT_low_pc')
highpc_attr = attributes.get('DW_AT_high_pc')
name_attr = attributes.get('DW_AT_name')
if not lowpc_attr or not highpc_attr or not name_attr:
continue
lowpc = lowpc_attr.value
if highpc_attr.form == 'DW_FORM_addr':
# highpc is an absolute address
size = highpc_attr.value - lowpc
elif highpc_attr.form in {'DW_FORM_data2','DW_FORM_data4',
'DW_FORM_data8', 'DW_FORM_data1',
'DW_FORM_udata'}:
# highpc is an offset from lowpc
size = highpc_attr.value
name = name_attr.value
subprograms[name] = (lowpc, size)
return subprograms
def test_debuglink(self):
with open('test/testfiles_for_unittests/debuglink', "rb") as elf_file:
elf = ELFFile(elf_file, stream_loader=self.stream_loader)
# Contains eh_frame and gnu_debuglink, but no DWARF
self.assertTrue(elf.has_dwarf_info(False))
self.assertFalse(elf.has_dwarf_info(True))
self.assertTrue(elf.has_dwarf_link())
link = elf.get_dwarf_link()
self.assertIsNotNone(link)
self.assertEqual(link.filename, b'debuglink.debug')
self.assertEqual(link.checksum, 0x29b7c5f1)
subprograms = self.subprograms_from_debuglink(elf)
self.assertEqual(subprograms, {b'main': (0x1161, 0x52), b'addNumbers': (0x1149, 0x18)})
# Test the filesystem aware ELFFile loading
elf = ELFFile.load_from_path('test/testfiles_for_unittests/debuglink')
subprograms = self.subprograms_from_debuglink(elf)
self.assertEqual(subprograms, {b'main': (0x1161, 0x52), b'addNumbers': (0x1149, 0x18)})
if __name__ == '__main__':
unittest.main()
|
