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