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Updated pelfy and using offset_in_section instead of fields['st_value']

This commit is contained in:
Nicolas 2026-02-12 23:54:20 +01:00
parent 58120f292c
commit bc0ccd90b7
1 changed files with 9 additions and 22 deletions
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31
src/copapy/_stencils.py
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@ -102,7 +102,7 @@ def get_last_call_in_function(func: pelfy.elf_symbol) -> int:
instruction_lengths = 4 if reloc.bits < 32 else 5 instruction_lengths = 4 if reloc.bits < 32 else 5
address_field_length = 4 address_field_length = 4
#print(f"-> {[r.fields['r_offset'] - func.fields['st_value'] for r in func.relocations]}") #print(f"-> {[r.fields['r_offset'] - func.fields['st_value'] for r in func.relocations]}")
return reloc.fields['r_offset'] - func.fields['st_value'] + address_field_length - instruction_lengths return reloc.fields['r_offset'] - func.offset_in_section + address_field_length - instruction_lengths
def get_op_after_last_call_in_function(func: pelfy.elf_symbol) -> int: def get_op_after_last_call_in_function(func: pelfy.elf_symbol) -> int:
@ -110,7 +110,7 @@ def get_op_after_last_call_in_function(func: pelfy.elf_symbol) -> int:
assert func.relocations, f'No call function in stencil function {func.name}.' assert func.relocations, f'No call function in stencil function {func.name}.'
reloc = func.relocations[-1] reloc = func.relocations[-1]
assert reloc.bits <= 32, "Relocation segment might be larger then 32 bit" assert reloc.bits <= 32, "Relocation segment might be larger then 32 bit"
return reloc.fields['r_offset'] - func.fields['st_value'] + 4 return reloc.fields['r_offset'] - func.offset_in_section + 4
class stencil_database(): class stencil_database():
@ -121,7 +121,7 @@ class stencil_database():
var_size (dict[str, int]): dictionary of object names and their sizes var_size (dict[str, int]): dictionary of object names and their sizes
byteorder (ByteOrder): byte order of the ELF file byteorder (ByteOrder): byte order of the ELF file
elf (elf_file): the loaded ELF file elf (elf_file): the loaded ELF file
thumb_mode (int): 1 if ARM in thumb mode, 0 otherwise thumb_mode (bool): entry_function_shell in ARM thumb mode
""" """
def __init__(self, obj_file: str | bytes): def __init__(self, obj_file: str | bytes):
@ -148,10 +148,7 @@ class stencil_database():
# if s.info == 'STT_OBJECT'} # if s.info == 'STT_OBJECT'}
self.byteorder: ByteOrder = self.elf.byteorder self.byteorder: ByteOrder = self.elf.byteorder
self.arm = '.ARM.attributes' in self.elf.sections self.thumb_mode = self.elf.symbols['entry_function_shell'].thumb_mode
# Returns 1 for ARM in thumb mode, 0 otherwise
self.thumb_mode = self.elf.symbols['entry_function_shell'].fields['st_value'] & 1
#for name in self.function_definitions.keys(): #for name in self.function_definitions.keys():
# sym = self.elf.symbols[name] # sym = self.elf.symbols[name]
@ -194,14 +191,14 @@ class stencil_database():
for reloc in symbol.relocations: for reloc in symbol.relocations:
# address to fist byte to patch relative to the start of the symbol # address to fist byte to patch relative to the start of the symbol
patch_offset = reloc.fields['r_offset'] - symbol.fields['st_value'] - start_index patch_offset = reloc.fields['r_offset'] - symbol.offset_in_section - start_index
if patch_offset < end_index - start_index: # Exclude the call to the result_* function if patch_offset < end_index - start_index: # Exclude the call to the result_* function
reloc_entry = relocation_entry(reloc.symbol.name, reloc_entry = relocation_entry(reloc.symbol.name,
reloc.symbol.info, reloc.symbol.info,
reloc.symbol.fields['st_value'], reloc.symbol.fields['st_value'], # LSB on ARM indicates thumb mode
reloc.symbol.fields['st_shndx'], reloc.symbol.fields['st_shndx'],
symbol.fields['st_value'], symbol.offset_in_section,
start_index, start_index,
reloc) reloc)
cache.append(reloc_entry) cache.append(reloc_entry)
@ -348,10 +345,7 @@ class stencil_database():
start_stencil, end_stencil = get_stencil_position(func) start_stencil, end_stencil = get_stencil_position(func)
assert func.section assert func.section
# For arm functions, mask out the thumb mode bit start_index = func.offset_in_file + start_stencil
function_offset = func.fields['st_value'] & ~int(self.arm)
start_index = func.section['sh_offset'] + function_offset + start_stencil
lengths = end_stencil - start_stencil lengths = end_stencil - start_stencil
self._stencil_cache[name] = (start_index, lengths) self._stencil_cache[name] = (start_index, lengths)
@ -389,7 +383,7 @@ class stencil_database():
def get_symbol_offset(self, name: str) -> int: def get_symbol_offset(self, name: str) -> int:
"""Returns the offset of a specified symbol in the section.""" """Returns the offset of a specified symbol in the section."""
return self.elf.symbols[name].fields['st_value'] return self.elf.symbols[name].offset_in_section
def get_symbol_section_index(self, name: str) -> int: def get_symbol_section_index(self, name: str) -> int:
"""Returns the section index for a specified symbol name.""" """Returns the section index for a specified symbol name."""
@ -420,13 +414,6 @@ class stencil_database():
func = self.elf.symbols[name] func = self.elf.symbols[name]
assert func.info == 'STT_FUNC', f"{name} is not a function" assert func.info == 'STT_FUNC', f"{name} is not a function"
# For arm functions, mask out the thumb mode bit
function_offset = func.fields['st_value'] & ~int(self.arm)
start_index = func.section['sh_offset'] + function_offset
lengths = end_stencil - start_stencil
#return self.elf.read_bytes(start_index, func.fields['st_size'])
if part == 'start': if part == 'start':
index = get_last_call_in_function(func) index = get_last_call_in_function(func)
return func.data[:index] return func.data[:index]