u-boot/tools/binman/elf_test.py
Simon Glass 056f0efd8b binman: Support reading the offset of an ELF-file symbol
Binman needs to be able to update the contents of an ELF file after it has
been build. To support this, add a function to locate the position of a
symbol's contents within the file.

Fix the comments on bss_data.c and Symbol while we are here.

Signed-off-by: Simon Glass <sjg@chromium.org>
2021-11-13 08:16:39 -07:00

263 lines
9.3 KiB
Python

# SPDX-License-Identifier: GPL-2.0+
# Copyright (c) 2017 Google, Inc
# Written by Simon Glass <sjg@chromium.org>
#
# Test for the elf module
import os
import shutil
import struct
import sys
import tempfile
import unittest
from binman import elf
from patman import command
from patman import test_util
from patman import tools
from patman import tout
binman_dir = os.path.dirname(os.path.realpath(sys.argv[0]))
class FakeEntry:
"""A fake Entry object, usedfor testing
This supports an entry with a given size.
"""
def __init__(self, contents_size):
self.contents_size = contents_size
self.data = tools.GetBytes(ord('a'), contents_size)
def GetPath(self):
return 'entry_path'
class FakeSection:
"""A fake Section object, used for testing
This has the minimum feature set needed to support testing elf functions.
A LookupSymbol() function is provided which returns a fake value for amu
symbol requested.
"""
def __init__(self, sym_value=1):
self.sym_value = sym_value
def GetPath(self):
return 'section_path'
def LookupImageSymbol(self, name, weak, msg, base_addr):
"""Fake implementation which returns the same value for all symbols"""
return self.sym_value
def GetImage(self):
return self
def BuildElfTestFiles(target_dir):
"""Build ELF files used for testing in binman
This compiles and links the test files into the specified directory. It the
Makefile and source files in the binman test/ directory.
Args:
target_dir: Directory to put the files into
"""
if not os.path.exists(target_dir):
os.mkdir(target_dir)
testdir = os.path.join(binman_dir, 'test')
# If binman is involved from the main U-Boot Makefile the -r and -R
# flags are set in MAKEFLAGS. This prevents this Makefile from working
# correctly. So drop any make flags here.
if 'MAKEFLAGS' in os.environ:
del os.environ['MAKEFLAGS']
try:
tools.Run('make', '-C', target_dir, '-f',
os.path.join(testdir, 'Makefile'), 'SRC=%s/' % testdir)
except ValueError as e:
# The test system seems to suppress this in a strange way
print(e)
class TestElf(unittest.TestCase):
@classmethod
def setUpClass(cls):
cls._indir = tempfile.mkdtemp(prefix='elf.')
tools.SetInputDirs(['.'])
BuildElfTestFiles(cls._indir)
@classmethod
def tearDownClass(cls):
if cls._indir:
shutil.rmtree(cls._indir)
@classmethod
def ElfTestFile(cls, fname):
return os.path.join(cls._indir, fname)
def testAllSymbols(self):
"""Test that we can obtain a symbol from the ELF file"""
fname = self.ElfTestFile('u_boot_ucode_ptr')
syms = elf.GetSymbols(fname, [])
self.assertIn('.ucode', syms)
def testRegexSymbols(self):
"""Test that we can obtain from the ELF file by regular expression"""
fname = self.ElfTestFile('u_boot_ucode_ptr')
syms = elf.GetSymbols(fname, ['ucode'])
self.assertIn('.ucode', syms)
syms = elf.GetSymbols(fname, ['missing'])
self.assertNotIn('.ucode', syms)
syms = elf.GetSymbols(fname, ['missing', 'ucode'])
self.assertIn('.ucode', syms)
def testMissingFile(self):
"""Test that a missing file is detected"""
entry = FakeEntry(10)
section = FakeSection()
with self.assertRaises(ValueError) as e:
syms = elf.LookupAndWriteSymbols('missing-file', entry, section)
self.assertIn("Filename 'missing-file' not found in input path",
str(e.exception))
def testOutsideFile(self):
"""Test a symbol which extends outside the entry area is detected"""
entry = FakeEntry(10)
section = FakeSection()
elf_fname = self.ElfTestFile('u_boot_binman_syms')
with self.assertRaises(ValueError) as e:
syms = elf.LookupAndWriteSymbols(elf_fname, entry, section)
self.assertIn('entry_path has offset 4 (size 8) but the contents size '
'is a', str(e.exception))
def testMissingImageStart(self):
"""Test that we detect a missing __image_copy_start symbol
This is needed to mark the start of the image. Without it we cannot
locate the offset of a binman symbol within the image.
"""
entry = FakeEntry(10)
section = FakeSection()
elf_fname = self.ElfTestFile('u_boot_binman_syms_bad')
self.assertEqual(elf.LookupAndWriteSymbols(elf_fname, entry, section),
None)
def testBadSymbolSize(self):
"""Test that an attempt to use an 8-bit symbol are detected
Only 32 and 64 bits are supported, since we need to store an offset
into the image.
"""
entry = FakeEntry(10)
section = FakeSection()
elf_fname =self.ElfTestFile('u_boot_binman_syms_size')
with self.assertRaises(ValueError) as e:
syms = elf.LookupAndWriteSymbols(elf_fname, entry, section)
self.assertIn('has size 1: only 4 and 8 are supported',
str(e.exception))
def testNoValue(self):
"""Test the case where we have no value for the symbol
This should produce -1 values for all thress symbols, taking up the
first 16 bytes of the image.
"""
entry = FakeEntry(24)
section = FakeSection(sym_value=None)
elf_fname = self.ElfTestFile('u_boot_binman_syms')
syms = elf.LookupAndWriteSymbols(elf_fname, entry, section)
self.assertEqual(tools.GetBytes(255, 20) + tools.GetBytes(ord('a'), 4),
entry.data)
def testDebug(self):
"""Check that enabling debug in the elf module produced debug output"""
try:
tout.Init(tout.DEBUG)
entry = FakeEntry(20)
section = FakeSection()
elf_fname = self.ElfTestFile('u_boot_binman_syms')
with test_util.capture_sys_output() as (stdout, stderr):
syms = elf.LookupAndWriteSymbols(elf_fname, entry, section)
self.assertTrue(len(stdout.getvalue()) > 0)
finally:
tout.Init(tout.WARNING)
def testMakeElf(self):
"""Test for the MakeElf function"""
outdir = tempfile.mkdtemp(prefix='elf.')
expected_text = b'1234'
expected_data = b'wxyz'
elf_fname = os.path.join(outdir, 'elf')
bin_fname = os.path.join(outdir, 'bin')
# Make an Elf file and then convert it to a fkat binary file. This
# should produce the original data.
elf.MakeElf(elf_fname, expected_text, expected_data)
objcopy, args = tools.GetTargetCompileTool('objcopy')
args += ['-O', 'binary', elf_fname, bin_fname]
stdout = command.Output(objcopy, *args)
with open(bin_fname, 'rb') as fd:
data = fd.read()
self.assertEqual(expected_text + expected_data, data)
shutil.rmtree(outdir)
def testDecodeElf(self):
"""Test for the MakeElf function"""
if not elf.ELF_TOOLS:
self.skipTest('Python elftools not available')
outdir = tempfile.mkdtemp(prefix='elf.')
expected_text = b'1234'
expected_data = b'wxyz'
elf_fname = os.path.join(outdir, 'elf')
elf.MakeElf(elf_fname, expected_text, expected_data)
data = tools.ReadFile(elf_fname)
load = 0xfef20000
entry = load + 2
expected = expected_text + expected_data
self.assertEqual(elf.ElfInfo(expected, load, entry, len(expected)),
elf.DecodeElf(data, 0))
self.assertEqual(elf.ElfInfo(b'\0\0' + expected[2:],
load, entry, len(expected)),
elf.DecodeElf(data, load + 2))
shutil.rmtree(outdir)
def testEmbedData(self):
"""Test for the GetSymbolFileOffset() function"""
if not elf.ELF_TOOLS:
self.skipTest('Python elftools not available')
fname = self.ElfTestFile('embed_data')
offset = elf.GetSymbolFileOffset(fname, ['embed_start', 'embed_end'])
start = offset['embed_start'].offset
end = offset['embed_end'].offset
data = tools.ReadFile(fname)
embed_data = data[start:end]
expect = struct.pack('<III', 0x1234, 0x5678, 0)
self.assertEqual(expect, embed_data)
def testEmbedFail(self):
"""Test calling GetSymbolFileOffset() without elftools"""
try:
old_val = elf.ELF_TOOLS
elf.ELF_TOOLS = False
fname = self.ElfTestFile('embed_data')
with self.assertRaises(ValueError) as e:
elf.GetSymbolFileOffset(fname, ['embed_start', 'embed_end'])
self.assertIn('Python elftools package is not available',
str(e.exception))
finally:
elf.ELF_TOOLS = old_val
def testEmbedDataNoSym(self):
"""Test for GetSymbolFileOffset() getting no symbols"""
if not elf.ELF_TOOLS:
self.skipTest('Python elftools not available')
fname = self.ElfTestFile('embed_data')
offset = elf.GetSymbolFileOffset(fname, ['missing_sym'])
self.assertEqual({}, offset)
if __name__ == '__main__':
unittest.main()