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# SPDX-License-Identifier: GPL-2.0+
# Copyright (c) 2016 Google, Inc
# Written by Simon Glass <>
# Handle various things related to ELF images
from collections import namedtuple, OrderedDict
import command
import os
import re
import struct
import tools
# This is enabled from
debug = False
Symbol = namedtuple('Symbol', ['section', 'address', 'size', 'weak'])
def GetSymbols(fname, patterns):
"""Get the symbols from an ELF file
fname: Filename of the ELF file to read
patterns: List of regex patterns to search for, each a string
None, if the file does not exist, or Dict:
key: Name of symbol
value: Hex value of symbol
stdout = command.Output('objdump', '-t', fname, raise_on_error=False)
lines = stdout.splitlines()
if patterns:
re_syms = re.compile('|'.join(patterns))
re_syms = None
syms = {}
syms_started = False
for line in lines:
if not line or not syms_started:
if 'SYMBOL TABLE' in line:
syms_started = True
line = None # Otherwise code coverage complains about 'continue'
if re_syms and not
space_pos = line.find(' ')
value, rest = line[:space_pos], line[space_pos + 1:]
flags = rest[:7]
parts = rest[7:].split()
section, size = parts[:2]
if len(parts) > 2:
name = parts[2]
syms[name] = Symbol(section, int(value, 16), int(size,16),
flags[1] == 'w')
return syms
def GetSymbolAddress(fname, sym_name):
"""Get a value of a symbol from an ELF file
fname: Filename of the ELF file to read
patterns: List of regex patterns to search for, each a string
Symbol value (as an integer) or None if not found
syms = GetSymbols(fname, [sym_name])
sym = syms.get(sym_name)
if not sym:
return None
return sym.address
def LookupAndWriteSymbols(elf_fname, entry, image):
"""Replace all symbols in an entry with their correct values
The entry contents is updated so that values for referenced symbols will be
visible at run time. This is done by finding out the symbols positions in
the entry (using the ELF file) and replacing them with values from binman's
data structures.
elf_fname: Filename of ELF image containing the symbol information for
entry: Entry to process
image: Image which can be used to lookup symbol values
fname = tools.GetInputFilename(elf_fname)
syms = GetSymbols(fname, ['image', 'binman'])
if not syms:
base = syms.get('__image_copy_start')
if not base:
for name, sym in syms.iteritems():
if name.startswith('_binman'):
msg = ("Image '%s': Symbol '%s'\n in entry '%s'" %
(image.GetPath(), name, entry.GetPath()))
offset = sym.address - base.address
if offset < 0 or offset + sym.size > entry.contents_size:
raise ValueError('%s has offset %x (size %x) but the contents '
'size is %x' % (entry.GetPath(), offset,
sym.size, entry.contents_size))
if sym.size == 4:
pack_string = '<I'
elif sym.size == 8:
pack_string = '<Q'
raise ValueError('%s has size %d: only 4 and 8 are supported' %
(msg, sym.size))
# Look up the symbol in our entry tables.
value = image.LookupSymbol(name, sym.weak, msg)
if value is not None:
value += base.address
value = -1
pack_string = pack_string.lower()
value_bytes = struct.pack(pack_string, value)
if debug:
print('%s:\n insert %s, offset %x, value %x, length %d' %
(msg, name, offset, value, len(value_bytes))) = ([:offset] + value_bytes +[offset + sym.size:])