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Merge pull request #4 from Nonannet/dev 

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Nicolas Kruse 2026-03-02 21:53:51 +01:00 committed by GitHub
parent 842be33939 345b0e6db8
commit b9f9032872
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9 changed files with 8532 additions and 35 deletions
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2
pyproject.toml
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@ -1,6 +1,6 @@
[project]
name = "pelfy"
version = "1.0.7"
version = "1.0.8"
authors = [
{ name="Nicolas Kruse", email="nicolas.kruse@nonan.net" },
]

52
src/pelfy/_fields_data.py
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@ -390,38 +390,42 @@ relocation_table_types = {
},
"EM_ARM": {
0: ("R_ARM_NONE", 0, ""),
1: ("R_ARM_PC24", 24, "S - P + A"),
2: ("R_ARM_ABS32", 32, "S + A"),
3: ("R_ARM_REL32", 32, "S - P + A"),
4: ("R_ARM_PC13", 13, "S - P + A"),
1: ("R_ARM_PC24", 24, "((S + A) | T) - P"),
2: ("R_ARM_ABS32", 32, "(S + A) | T"),
3: ("R_ARM_REL32", 32, "((S + A) | T) - P"),
4: ("R_ARM_LDR_PC_G0", 12, "S + A - P"),
5: ("R_ARM_ABS16", 16, "S + A"),
6: ("R_ARM_ABS12", 12, "S + A"),
7: ("R_ARM_THM_ABS5", 5, "S + A"),
8: ("R_ARM_ABS8", 8, "S + A"),
9: ("R_ARM_SBREL32", 32, "S - B + A"),
10: ("R_ARM_THM_PC22", 22, "S - P + A"),
11: ("R_ARM_THM_PC8", 8, "S - P + A"),
12: ("Reserved", 0, ""),
13: ("R_ARM_SWI24", 24, "S + A"),
9: ("R_ARM_SBREL32", 32, "((S + A) | T) - B(S)"),
10: ("R_ARM_THM_CALL", 22, "((S + A) | T) - P"),
11: ("R_ARM_THM_PC8", 8, "S + A - Pa"),
12: ("R_ARM_BREL_ADJ", 0, "ChangeIn[B(S)] + A"),
13: ("R_ARM_TLS_DESC", 0, ""),
14: ("R_ARM_THM_SWI8", 8, "S + A"),
15: ("R_ARM_XPC25", 25, ""),
16: ("R_ARM_THM_XPC22", 22, ""),
28: ("R_ARM_CALL", 24, "((S + A) - P) >> 2"),
29: ("R_ARM_JUMP24", 24, "((S + A) - P) >> 2"),
30: ("R_ARM_TLS_DESC", 0, ""),
32: ("R_ARM_ALU_PCREL_7_0", 7, "(S - P + A) & 0x000000FF"),
33: ("R_ARM_ALU_PCREL_15_8", 15, "(S - P + A) & 0x0000FF00"),
34: ("R_ARM_ALU_PCREL_23_15", 23, "(S - P + A) & 0x00FF0000"),
35: ("R_ARM_LDR_SBREL_11_0", 11, "(S - B + A) & 0x00000FFF"),
36: ("R_ARM_ALU_SBREL_19_12", 19, "(S - B + A) & 0x000FF000"),
37: ("R_ARM_ALU_SBREL_27_20", 27, "(S - B + A) & 0x0FF00000"),
38: ("R_ARM_RELABS32", 32, "S + A or S - P + A"),
39: ("R_ARM_ROSEGREL32", 32, "S - E + A"),
17: ("R_ARM_TLS_DTPMOD32", 0, "Module[S]"),
18: ("R_ARM_TLS_DTPOFF32", 0, "S + A - TLS"),
19: ("R_ARM_TLS_TPOFF32", 0, "S + A - tp"),
20: ("R_ARM_COPY", 0, ""),
21: ("R_ARM_GLOB_DAT", 0, "(S + A) | T"),
22: ("R_ARM_JUMP_SLOT", 0, "(S + A) | T"),
23: ("R_ARM_RELATIVE", 0, "B(S) + A"),
24: ("R_ARM_GOTOFF32", 0, "((S + A) | T) - GOT_ORG"),
25: ("R_ARM_BASE_PREL", 0, "B(S) + A - P"),
26: ("R_ARM_GOT_BREL", 0, "GOT(S) + A - GOT_ORG"),
27: ("R_ARM_PLT32", 0, "((S + A) | T) - P"),
28: ("R_ARM_CALL", 24, "((S + A) | T) - P"),
29: ("R_ARM_JUMP24", 24, "((S + A) | T) - P"),
30: ("R_ARM_THM_JUMP24", 24, "((S + A) | T) - P"),
40: ("R_ARM_V4BX", 0, ""),
41: ("R_ARM_STKCHK", 0, ""),
42: ("R_ARM_THM_STKCHK", 0, ""),
43: ("R_ARM_MOVW_ABS_NC", 16, "S + A"),
44: ("R_ARM_MOVT_ABS", 16, "S + A")
42: ("R_ARM_PREL31", 31, "((S + A) | T) - P"),
43: ("R_ARM_MOVW_ABS_NC", 16, "(S + A) | T"),
44: ("R_ARM_MOVT_ABS", 16, "S + A"),
47: ("R_ARM_THM_MOVW_ABS_NC", 16, "(S + A) | T"),
48: ("R_ARM_THM_MOVT_ABS", 16, "S + A"),
},
"EM_AARCH64": {
0: ("R_AARCH64_NONE", 0, ""),

62
src/pelfy/_main.py
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@ -9,6 +9,7 @@ Typical usage example:
from . import _fields_data as fdat
from . import _output_formatter
from typing import TypeVar, Literal, Iterable, Generic, Iterator, Generator, Optional, Union
import warnings
_T = TypeVar('_T')
@ -26,6 +27,14 @@ def open_elf_file(file_path: str) -> 'elf_file':
return elf_file(f.read())
def _sign_extend(value: int, bits: int) -> int:
"""Sign-extend a value with given bit width to 32 bits."""
sign_bit = 1 << (bits - 1)
if value & sign_bit:
return value - (1 << bits)
return value
class elf_symbol():
"""A class for representing data of an ELF symbol
@ -42,6 +51,7 @@ class elf_symbol():
offset_in_section: Position of first symbol byte
relative to section start
offset_in_file: Position of first symbol byte in object file
size: size of symbol in bytes
fields: All symbol header fields as dict
"""
@ -71,19 +81,17 @@ class elf_symbol():
self.thumb_mode = bool((file.architecture == 'EM_ARM') & fields['st_value'] & 1)
self.offset_in_section = fields['st_value'] & ~int(self.thumb_mode)
self.offset_in_file = self.section['sh_offset'] + self.offset_in_section if self.section else 0
self.size = self.fields['st_size']
@property
def data(self) -> bytes:
"""Returns the binary data the symbol is pointing to.
The offset in the ELF file is calculated by:
sections[symbol.st_shndx].sh_offset + symbol.st_value
"""
assert self.section, 'This symbol is not associated to a data section'
if self.section.type == 'SHT_NOBITS':
return b'\x00' * self['st_size']
else:
offset = self.section['sh_offset'] + self['st_value']
return self.file.read_bytes(offset, self['st_size'])
return self.file.read_bytes(self.offset_in_file, self['st_size'])
@property
def data_hex(self) -> str:
@ -102,7 +110,7 @@ class elf_symbol():
assert self.section and self.section.type == 'SHT_PROGBITS'
for reloc in self.file.get_relocations():
if reloc.target_section == self.section:
offset = reloc['r_offset'] - self['st_value']
offset = reloc['r_offset'] - self.offset_in_section
if 0 <= offset < self['st_size']:
ret.append(reloc)
return relocation_list(ret)
@ -528,7 +536,7 @@ class elf_file:
if reloc_types and 'A' in reloc_types[relocation_type][2]:
name = reloc_types[relocation_type][0]
sh = self.sections[reloc_section['sh_info']]
field = self.read_int(r_offset + sh['sh_offset'], 4, True)
field = self.read_int(r_offset + sh['sh_offset'], 4, False)
if name in ('R_386_PC32', 'R_386_32', 'R_X86_64_PC32', 'R_X86_64_PLT32', 'R_ARM_REL32', 'R_ARM_ABS32'):
return field
if name == 'R_ARM_MOVW_ABS_NC':
@ -544,11 +552,45 @@ class elf_file:
if imm24 & 0x800000:
imm24 |= ~0xFFFFFF
return imm24 << 2
if '_THM_' in name:
print('Warning: Thumb relocation addend extraction is not implemented')
return 0
if name == 'R_ARM_THM_PC22':
# BL Encoding T2
h1 = field & 0xFFFF
h2 = (field >> 16) & 0xFFFF
s = (h1 >> 10) & 0x1 # Bit 10 of h1
imm10H = h1 & 0x3FF # Bits 9..0 of h1
j1 = (h2 >> 13) & 0x1 # Bit 13 of h2
j2 = (h2 >> 11) & 0x1 # Bit 11 of h2
imm10L = (h2 >> 1) & 0x3FF # Bits 10..1 of h2
i1 = ~(j1 ^ s) & 0x1
i2 = ~(j2 ^ s) & 0x1
imm22 = (s << 21) | (i1 << 20) | (i2 << 19) | (imm10H << 9) | imm10L
imm32 = _sign_extend(imm22 << 1, 23) # Shift left by 1, then sign-extend 23 bits
return imm32
if name in ('R_ARM_THM_JUMP24', 'R_ARM_THM_CALL'):
# B.W Encoding T4
h1 = field & 0xFFFF
h2 = (field >> 16) & 0xFFFF
s = (h1 >> 10) & 0x1 # Bit 10 of h1
imm10 = h1 & 0x3FF # Bits 9..0 of h1
j1 = (h2 >> 13) & 0x1 # Bit 13 of h2
j2 = (h2 >> 11) & 0x1 # Bit 11 of h2
imm11 = h2 & 0x7FF # Bits 10..0 of h2
i1 = ~(j1 ^ s) & 0x1
i2 = ~(j2 ^ s) & 0x1
imm24 = (s << 23) | (i1 << 22) | (i2 << 21) | (imm10 << 11) | imm11
imm32 = _sign_extend(imm24 << 1, 25) # Shift left by 1, then sign-extend 25 bits
return imm32
if name == 'R_ARM_THM_MOVW_ABS_NC' or name == 'R_ARM_THM_MOVT_ABS':
i = (field >> 10) & 1
imm4 = field & 0xF
imm3 = (field >> 28) & 0x7
imm8 = (field >> 16) & 0xFF
imm16 = imm8 | (imm3 << 8) | (i << 11) | (imm4 << 12)
if name == 'R_ARM_THM_MOVT_ABS':
return imm16 << 16
return imm16
if '_MIPS_' in name:
print('Warning: MIPS relocations addend extraction is not implemented')
warnings.warn('Warning: MIPS relocations addend extraction is not implemented', stacklevel=2)
return 0
raise NotImplementedError(f"Relocation addend extraction for {name} is not implemented")

4109
tests/obj/stencils_armv7_O3.asm Normal file
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tests/obj/stencils_armv7_O3.o Normal file
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tests/obj/stencils_armv7thumb_O3_THM_MOVW.asm Normal file
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tests/obj/stencils_armv7thumb_O3_THM_MOVW.o Normal file
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62
tests/test_arm_addend.py Normal file
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@ -0,0 +1,62 @@
import pelfy._main as _main
import os
def test_arm_addend_extraction() -> None:
# Path to the test object file
obj_path = os.path.join('tests', 'obj', 'stencils_armv7_O3.o')
elf = _main.open_elf_file(obj_path)
# Collect all ARM relocations
reloc_addends: list[tuple[str, int, int, str]] = []
for reloc in elf.get_relocations():
if reloc.type.startswith('R_ARM'):
reloc_addends.append((reloc.type, reloc['r_offset'], reloc['r_addend'], reloc.symbol.name))
# Reference values from stencils_armv7_O3.asm (addend = 0 for V4BX, -8 for JUMP24/CALL)
reference = [
('R_ARM_V4BX', 0xB4, 0, ''),
('R_ARM_V4BX', 0xC0, 0, ''),
('R_ARM_V4BX', 0xD0, 0, ''),
('R_ARM_V4BX', 0x114, 0, ''),
('R_ARM_V4BX', 0x144, 0, ''),
('R_ARM_V4BX', 0x148, 0, ''),
('R_ARM_JUMP24', 0x124, -8, '__aeabi_idiv0'),
('R_ARM_JUMP24', 0x14, -8, 'auxsub_get_42'),
('R_ARM_CALL', 0x10, -8, 'result_int'),
('R_ARM_JUMP24', 0xC, -8, 'result_float_int'),
('R_ARM_JUMP24', 0xC, -8, 'result_float_float'),
('R_ARM_JUMP24', 0xC, -8, 'result_int_int'),
('R_ARM_JUMP24', 0xC, -8, 'result_int_float'),
('R_ARM_CALL', 0xC, -8, 'aux_get_42'),
('R_ARM_JUMP24', 0x14, -8, 'result_float'),
('R_ARM_CALL', 0x4, -8, 'aux_get_42'),
('R_ARM_JUMP24', 0xC, -8, 'result_float'),
('R_ARM_JUMP24', 0x4, -8, 'result_int'),
('R_ARM_JUMP24', 0x4, -8, 'result_float'),
('R_ARM_JUMP24', 0x2C, -8, 'result_float'),
('R_ARM_CALL', 0x30, -8, 'sqrtf'),
('R_ARM_JUMP24', 0x24, -8, 'result_float'),
('R_ARM_CALL', 0x28, -8, 'sqrtf'),
('R_ARM_CALL', 0xC, -8, 'expf'),
('R_ARM_JUMP24', 0x14, -8, 'result_float'),
('R_ARM_CALL', 0x4, -8, 'expf'),
('R_ARM_JUMP24', 0xC, -8, 'result_float'),
('R_ARM_CALL', 0xC, -8, 'logf'),
('R_ARM_JUMP24', 0x14, -8, 'result_float'),
('R_ARM_CALL', 0x4, -8, 'logf'),
('R_ARM_JUMP24', 0xC, -8, 'result_float'),
('R_ARM_CALL', 0xC, -8, 'sinf'),
('R_ARM_JUMP24', 0x14, -8, 'result_float'),
('R_ARM_CALL', 0x4, -8, 'sinf'),
('R_ARM_JUMP24', 0xC, -8, 'result_float'),
]
# For each reference, check that at least one matching relocation has the expected addend
for ref_type, ref_offset, ref_addend, ref_symbol in reference:
found = False
addend = None
for typ, offset, addend, symbol in reloc_addends:
if typ == ref_type and offset == ref_offset and symbol == ref_symbol and addend == ref_addend:
found = True
break
assert found, f"Missing or incorrect addend for {ref_type} offset=0x{ref_offset:X} symbol={ref_symbol} (value={addend}, expected {ref_addend})"

67
tests/test_thumb_addend.py Normal file
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@ -0,0 +1,67 @@
import pelfy._main as _main
import os
from typing import Union
def test_thumb_addend_extraction() -> None:
# Path to the test object file
obj_path = os.path.join('tests', 'obj', 'stencils_armv7thumb_O3_THM_MOVW.o')
elf = _main.open_elf_file(obj_path)
# Collect all relocations of interest
reloc_addends: list[tuple[str, int, int, str]] = []
for reloc in elf.get_relocations():
if reloc.type.startswith('R_ARM_THM'):
reloc_addends.append((reloc.type, reloc['r_offset'], reloc['r_addend'], reloc.symbol.name))
# Reference values from the .asm file (addend = 0 for all Thumb relocations)
reference: list[tuple[str, Union[int, None], int, str]] = [
('R_ARM_THM_MOVW_ABS_NC', None, 0, 'dummy_int'),
('R_ARM_THM_MOVT_ABS', None, 0, 'dummy_int'),
('R_ARM_THM_MOVW_ABS_NC', None, 0, 'dummy_float'),
('R_ARM_THM_MOVT_ABS', None, 0, 'dummy_float'),
('R_ARM_THM_JUMP24', 0x14, -4, 'auxsub_get_42'),
('R_ARM_THM_CALL', 0xA, -4, 'result_int'),
('R_ARM_THM_JUMP24', 0xA, -4, 'result_float_int'),
('R_ARM_THM_JUMP24', 0xC, -4, 'result_float_float'),
('R_ARM_THM_JUMP24', 0xA, -4, 'result_int_int'),
('R_ARM_THM_JUMP24', 0xC, -4, 'result_int_float'),
('R_ARM_THM_CALL', 0xA, -4, 'aux_get_42'),
('R_ARM_THM_JUMP24', 0x12, -4, 'result_float'),
('R_ARM_THM_CALL', 0x2, -4, 'aux_get_42'),
('R_ARM_THM_JUMP24', 0xA, -4, 'result_float'),
('R_ARM_THM_JUMP24', 0x2, -4, 'result_int'),
('R_ARM_THM_JUMP24', 0x4, -4, 'result_float'),
('R_ARM_THM_JUMP24', 0x28, -4, 'result_float'),
('R_ARM_THM_CALL', 0x2C, -4, 'sqrtf'),
('R_ARM_THM_JUMP24', 0x20, -4, 'result_float'),
('R_ARM_THM_CALL', 0x24, -4, 'sqrtf'),
('R_ARM_THM_CALL', 0xA, -4, 'expf'),
('R_ARM_THM_JUMP24', 0x12, -4, 'result_float'),
('R_ARM_THM_CALL', 0x2, -4, 'expf'),
('R_ARM_THM_JUMP24', 0xA, -4, 'result_float'),
('R_ARM_THM_CALL', 0xA, -4, 'logf'),
('R_ARM_THM_JUMP24', 0x12, -4, 'result_float'),
('R_ARM_THM_CALL', 0x2, -4, 'logf'),
('R_ARM_THM_JUMP24', 0xA, -4, 'result_float'),
('R_ARM_THM_CALL', 0xA, -4, 'sinf'),
('R_ARM_THM_JUMP24', 0x12, -4, 'result_float'),
('R_ARM_THM_CALL', 0x2, -4, 'sinf'),
('R_ARM_THM_JUMP24', 0xA, -4, 'result_float'),
('R_ARM_THM_CALL', 0xA, -4, 'cosf'),
('R_ARM_THM_JUMP24', 0x12, -4, 'result_float'),
('R_ARM_THM_CALL', 0x2, -4, 'cosf'),
('R_ARM_THM_JUMP24', 0xA, -4, 'result_float'),
('R_ARM_THM_CALL', 0xA, -4, 'tanf'),
('R_ARM_THM_JUMP24', 0x12, -4, 'result_float'),
('R_ARM_THM_CALL', 0x2, -4, 'tanf'),
]
# For each reference, check that at least one matching relocation has the expected addend
for ref_type, _, ref_addend, ref_symbol in reference:
found = False
addend = 0
for typ, offset, addend, symbol in reloc_addends:
if typ == ref_type and symbol == ref_symbol and addend == ref_addend:
found = True
break
assert found, f"Missing or incorrect addend for {ref_type} {ref_symbol} (value={addend:X}, expected {ref_addend})"