mirror of
https://github.com/AsahiLinux/u-boot
synced 2024-11-18 10:48:51 +00:00
39f4a85bb2
Add a function which checks whether data is in ELF format or not. This will be used by binman to check this for entries. Signed-off-by: Simon Glass <sjg@chromium.org>
535 lines
18 KiB
Python
535 lines
18 KiB
Python
# SPDX-License-Identifier: GPL-2.0+
|
|
# Copyright (c) 2016 Google, Inc
|
|
# Written by Simon Glass <sjg@chromium.org>
|
|
#
|
|
# Handle various things related to ELF images
|
|
#
|
|
|
|
from collections import namedtuple, OrderedDict
|
|
import io
|
|
import os
|
|
import re
|
|
import shutil
|
|
import struct
|
|
import tempfile
|
|
|
|
from patman import command
|
|
from patman import tools
|
|
from patman import tout
|
|
|
|
ELF_TOOLS = True
|
|
try:
|
|
from elftools.elf.elffile import ELFFile
|
|
from elftools.elf.elffile import ELFError
|
|
from elftools.elf.sections import SymbolTableSection
|
|
except: # pragma: no cover
|
|
ELF_TOOLS = False
|
|
|
|
# BSYM in little endian, keep in sync with include/binman_sym.h
|
|
BINMAN_SYM_MAGIC_VALUE = 0x4d595342
|
|
|
|
# Information about an EFL symbol:
|
|
# section (str): Name of the section containing this symbol
|
|
# address (int): Address of the symbol (its value)
|
|
# size (int): Size of the symbol in bytes
|
|
# weak (bool): True if the symbol is weak
|
|
# offset (int or None): Offset of the symbol's data in the ELF file, or None if
|
|
# not known
|
|
Symbol = namedtuple('Symbol', ['section', 'address', 'size', 'weak', 'offset'])
|
|
|
|
# Information about an ELF file:
|
|
# data: Extracted program contents of ELF file (this would be loaded by an
|
|
# ELF loader when reading this file
|
|
# load: Load address of code
|
|
# entry: Entry address of code
|
|
# memsize: Number of bytes in memory occupied by loading this ELF file
|
|
ElfInfo = namedtuple('ElfInfo', ['data', 'load', 'entry', 'memsize'])
|
|
|
|
|
|
def GetSymbols(fname, patterns):
|
|
"""Get the symbols from an ELF file
|
|
|
|
Args:
|
|
fname: Filename of the ELF file to read
|
|
patterns: List of regex patterns to search for, each a string
|
|
|
|
Returns:
|
|
None, if the file does not exist, or Dict:
|
|
key: Name of symbol
|
|
value: Hex value of symbol
|
|
"""
|
|
stdout = tools.run('objdump', '-t', fname)
|
|
lines = stdout.splitlines()
|
|
if patterns:
|
|
re_syms = re.compile('|'.join(patterns))
|
|
else:
|
|
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'
|
|
continue
|
|
if re_syms and not re_syms.search(line):
|
|
continue
|
|
|
|
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] if parts[2] != '.hidden' else parts[3]
|
|
syms[name] = Symbol(section, int(value, 16), int(size, 16),
|
|
flags[1] == 'w', None)
|
|
|
|
# Sort dict by address
|
|
return OrderedDict(sorted(syms.items(), key=lambda x: x[1].address))
|
|
|
|
def _GetFileOffset(elf, addr):
|
|
"""Get the file offset for an address
|
|
|
|
Args:
|
|
elf (ELFFile): ELF file to check
|
|
addr (int): Address to search for
|
|
|
|
Returns
|
|
int: Offset of that address in the ELF file, or None if not valid
|
|
"""
|
|
for seg in elf.iter_segments():
|
|
seg_end = seg['p_vaddr'] + seg['p_filesz']
|
|
if seg.header['p_type'] == 'PT_LOAD':
|
|
if addr >= seg['p_vaddr'] and addr < seg_end:
|
|
return addr - seg['p_vaddr'] + seg['p_offset']
|
|
|
|
def GetFileOffset(fname, addr):
|
|
"""Get the file offset for an address
|
|
|
|
Args:
|
|
fname (str): Filename of ELF file to check
|
|
addr (int): Address to search for
|
|
|
|
Returns
|
|
int: Offset of that address in the ELF file, or None if not valid
|
|
"""
|
|
if not ELF_TOOLS:
|
|
raise ValueError("Python: No module named 'elftools'")
|
|
with open(fname, 'rb') as fd:
|
|
elf = ELFFile(fd)
|
|
return _GetFileOffset(elf, addr)
|
|
|
|
def GetSymbolFromAddress(fname, addr):
|
|
"""Get the symbol at a particular address
|
|
|
|
Args:
|
|
fname (str): Filename of ELF file to check
|
|
addr (int): Address to search for
|
|
|
|
Returns:
|
|
str: Symbol name, or None if no symbol at that address
|
|
"""
|
|
if not ELF_TOOLS:
|
|
raise ValueError("Python: No module named 'elftools'")
|
|
with open(fname, 'rb') as fd:
|
|
elf = ELFFile(fd)
|
|
syms = GetSymbols(fname, None)
|
|
for name, sym in syms.items():
|
|
if sym.address == addr:
|
|
return name
|
|
|
|
def GetSymbolFileOffset(fname, patterns):
|
|
"""Get the symbols from an ELF file
|
|
|
|
Args:
|
|
fname: Filename of the ELF file to read
|
|
patterns: List of regex patterns to search for, each a string
|
|
|
|
Returns:
|
|
None, if the file does not exist, or Dict:
|
|
key: Name of symbol
|
|
value: Hex value of symbol
|
|
"""
|
|
if not ELF_TOOLS:
|
|
raise ValueError("Python: No module named 'elftools'")
|
|
|
|
syms = {}
|
|
with open(fname, 'rb') as fd:
|
|
elf = ELFFile(fd)
|
|
|
|
re_syms = re.compile('|'.join(patterns))
|
|
for section in elf.iter_sections():
|
|
if isinstance(section, SymbolTableSection):
|
|
for symbol in section.iter_symbols():
|
|
if not re_syms or re_syms.search(symbol.name):
|
|
addr = symbol.entry['st_value']
|
|
syms[symbol.name] = Symbol(
|
|
section.name, addr, symbol.entry['st_size'],
|
|
symbol.entry['st_info']['bind'] == 'STB_WEAK',
|
|
_GetFileOffset(elf, addr))
|
|
|
|
# Sort dict by address
|
|
return OrderedDict(sorted(syms.items(), key=lambda x: x[1].address))
|
|
|
|
def GetSymbolAddress(fname, sym_name):
|
|
"""Get a value of a symbol from an ELF file
|
|
|
|
Args:
|
|
fname: Filename of the ELF file to read
|
|
patterns: List of regex patterns to search for, each a string
|
|
|
|
Returns:
|
|
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 GetPackString(sym, msg):
|
|
"""Get the struct.pack/unpack string to use with a given symbol
|
|
|
|
Args:
|
|
sym (Symbol): Symbol to check. Only the size member is checked
|
|
@msg (str): String which indicates the entry being processed, used for
|
|
errors
|
|
|
|
Returns:
|
|
str: struct string to use, .e.g. '<I'
|
|
|
|
Raises:
|
|
ValueError: Symbol has an unexpected size
|
|
"""
|
|
if sym.size == 4:
|
|
return '<I'
|
|
elif sym.size == 8:
|
|
return '<Q'
|
|
else:
|
|
raise ValueError('%s has size %d: only 4 and 8 are supported' %
|
|
(msg, sym.size))
|
|
|
|
def LookupAndWriteSymbols(elf_fname, entry, section, is_elf=False):
|
|
"""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 offsets in the
|
|
entry (using the ELF file) and replacing them with values from binman's data
|
|
structures.
|
|
|
|
Args:
|
|
elf_fname: Filename of ELF image containing the symbol information for
|
|
entry
|
|
entry: Entry to process
|
|
section: Section which can be used to lookup symbol values
|
|
"""
|
|
fname = tools.get_input_filename(elf_fname)
|
|
syms = GetSymbols(fname, ['image', 'binman'])
|
|
if is_elf:
|
|
if not ELF_TOOLS:
|
|
msg = ("Section '%s': entry '%s'" %
|
|
(section.GetPath(), entry.GetPath()))
|
|
raise ValueError(f'{msg}: Cannot write symbols to an ELF file without Python elftools')
|
|
new_syms = {}
|
|
with open(fname, 'rb') as fd:
|
|
elf = ELFFile(fd)
|
|
for name, sym in syms.items():
|
|
offset = _GetFileOffset(elf, sym.address)
|
|
new_syms[name] = Symbol(sym.section, sym.address, sym.size,
|
|
sym.weak, offset)
|
|
syms = new_syms
|
|
|
|
if not syms:
|
|
tout.debug('LookupAndWriteSymbols: no syms')
|
|
return
|
|
base = syms.get('__image_copy_start')
|
|
if not base and not is_elf:
|
|
tout.debug('LookupAndWriteSymbols: no base')
|
|
return
|
|
base_addr = 0 if is_elf else base.address
|
|
for name, sym in syms.items():
|
|
if name.startswith('_binman'):
|
|
msg = ("Section '%s': Symbol '%s'\n in entry '%s'" %
|
|
(section.GetPath(), name, entry.GetPath()))
|
|
if is_elf:
|
|
# For ELF files, use the file offset
|
|
offset = sym.offset
|
|
else:
|
|
# For blobs use the offset of the symbol, calculated by
|
|
# subtracting the base address which by definition is at the
|
|
# start
|
|
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))
|
|
pack_string = GetPackString(sym, msg)
|
|
if name == '_binman_sym_magic':
|
|
value = BINMAN_SYM_MAGIC_VALUE
|
|
else:
|
|
# Look up the symbol in our entry tables.
|
|
value = section.GetImage().LookupImageSymbol(name, sym.weak,
|
|
msg, base_addr)
|
|
if value is None:
|
|
value = -1
|
|
pack_string = pack_string.lower()
|
|
value_bytes = struct.pack(pack_string, value)
|
|
tout.debug('%s:\n insert %s, offset %x, value %x, length %d' %
|
|
(msg, name, offset, value, len(value_bytes)))
|
|
entry.data = (entry.data[:offset] + value_bytes +
|
|
entry.data[offset + sym.size:])
|
|
|
|
def GetSymbolValue(sym, data, msg):
|
|
"""Get the value of a symbol
|
|
|
|
This can only be used on symbols with an integer value.
|
|
|
|
Args:
|
|
sym (Symbol): Symbol to check
|
|
data (butes): Data for the ELF file - the symbol data appears at offset
|
|
sym.offset
|
|
@msg (str): String which indicates the entry being processed, used for
|
|
errors
|
|
|
|
Returns:
|
|
int: Value of the symbol
|
|
|
|
Raises:
|
|
ValueError: Symbol has an unexpected size
|
|
"""
|
|
pack_string = GetPackString(sym, msg)
|
|
value = struct.unpack(pack_string, data[sym.offset:sym.offset + sym.size])
|
|
return value[0]
|
|
|
|
def MakeElf(elf_fname, text, data):
|
|
"""Make an elf file with the given data in a single section
|
|
|
|
The output file has a several section including '.text' and '.data',
|
|
containing the info provided in arguments.
|
|
|
|
Args:
|
|
elf_fname: Output filename
|
|
text: Text (code) to put in the file's .text section
|
|
data: Data to put in the file's .data section
|
|
"""
|
|
outdir = tempfile.mkdtemp(prefix='binman.elf.')
|
|
s_file = os.path.join(outdir, 'elf.S')
|
|
|
|
# Spilt the text into two parts so that we can make the entry point two
|
|
# bytes after the start of the text section
|
|
text_bytes1 = ['\t.byte\t%#x' % byte for byte in text[:2]]
|
|
text_bytes2 = ['\t.byte\t%#x' % byte for byte in text[2:]]
|
|
data_bytes = ['\t.byte\t%#x' % byte for byte in data]
|
|
with open(s_file, 'w') as fd:
|
|
print('''/* Auto-generated C program to produce an ELF file for testing */
|
|
|
|
.section .text
|
|
.code32
|
|
.globl _start
|
|
.type _start, @function
|
|
%s
|
|
_start:
|
|
%s
|
|
.ident "comment"
|
|
|
|
.comm fred,8,4
|
|
|
|
.section .empty
|
|
.globl _empty
|
|
_empty:
|
|
.byte 1
|
|
|
|
.globl ernie
|
|
.data
|
|
.type ernie, @object
|
|
.size ernie, 4
|
|
ernie:
|
|
%s
|
|
''' % ('\n'.join(text_bytes1), '\n'.join(text_bytes2), '\n'.join(data_bytes)),
|
|
file=fd)
|
|
lds_file = os.path.join(outdir, 'elf.lds')
|
|
|
|
# Use a linker script to set the alignment and text address.
|
|
with open(lds_file, 'w') as fd:
|
|
print('''/* Auto-generated linker script to produce an ELF file for testing */
|
|
|
|
PHDRS
|
|
{
|
|
text PT_LOAD ;
|
|
data PT_LOAD ;
|
|
empty PT_LOAD FLAGS ( 6 ) ;
|
|
note PT_NOTE ;
|
|
}
|
|
|
|
SECTIONS
|
|
{
|
|
. = 0xfef20000;
|
|
ENTRY(_start)
|
|
.text . : SUBALIGN(0)
|
|
{
|
|
*(.text)
|
|
} :text
|
|
.data : {
|
|
*(.data)
|
|
} :data
|
|
_bss_start = .;
|
|
.empty : {
|
|
*(.empty)
|
|
} :empty
|
|
/DISCARD/ : {
|
|
*(.note.gnu.property)
|
|
}
|
|
.note : {
|
|
*(.comment)
|
|
} :note
|
|
.bss _bss_start (OVERLAY) : {
|
|
*(.bss)
|
|
}
|
|
}
|
|
''', file=fd)
|
|
# -static: Avoid requiring any shared libraries
|
|
# -nostdlib: Don't link with C library
|
|
# -Wl,--build-id=none: Don't generate a build ID, so that we just get the
|
|
# text section at the start
|
|
# -m32: Build for 32-bit x86
|
|
# -T...: Specifies the link script, which sets the start address
|
|
cc, args = tools.get_target_compile_tool('cc')
|
|
args += ['-static', '-nostdlib', '-Wl,--build-id=none', '-m32', '-T',
|
|
lds_file, '-o', elf_fname, s_file]
|
|
stdout = command.output(cc, *args)
|
|
shutil.rmtree(outdir)
|
|
|
|
def DecodeElf(data, location):
|
|
"""Decode an ELF file and return information about it
|
|
|
|
Args:
|
|
data: Data from ELF file
|
|
location: Start address of data to return
|
|
|
|
Returns:
|
|
ElfInfo object containing information about the decoded ELF file
|
|
"""
|
|
file_size = len(data)
|
|
with io.BytesIO(data) as fd:
|
|
elf = ELFFile(fd)
|
|
data_start = 0xffffffff;
|
|
data_end = 0;
|
|
mem_end = 0;
|
|
virt_to_phys = 0;
|
|
|
|
for i in range(elf.num_segments()):
|
|
segment = elf.get_segment(i)
|
|
if segment['p_type'] != 'PT_LOAD' or not segment['p_memsz']:
|
|
skipped = 1 # To make code-coverage see this line
|
|
continue
|
|
start = segment['p_paddr']
|
|
mend = start + segment['p_memsz']
|
|
rend = start + segment['p_filesz']
|
|
data_start = min(data_start, start)
|
|
data_end = max(data_end, rend)
|
|
mem_end = max(mem_end, mend)
|
|
if not virt_to_phys:
|
|
virt_to_phys = segment['p_paddr'] - segment['p_vaddr']
|
|
|
|
output = bytearray(data_end - data_start)
|
|
for i in range(elf.num_segments()):
|
|
segment = elf.get_segment(i)
|
|
if segment['p_type'] != 'PT_LOAD' or not segment['p_memsz']:
|
|
skipped = 1 # To make code-coverage see this line
|
|
continue
|
|
start = segment['p_paddr']
|
|
offset = 0
|
|
if start < location:
|
|
offset = location - start
|
|
start = location
|
|
# A legal ELF file can have a program header with non-zero length
|
|
# but zero-length file size and a non-zero offset which, added
|
|
# together, are greater than input->size (i.e. the total file size).
|
|
# So we need to not even test in the case that p_filesz is zero.
|
|
# Note: All of this code is commented out since we don't have a test
|
|
# case for it.
|
|
size = segment['p_filesz']
|
|
#if not size:
|
|
#continue
|
|
#end = segment['p_offset'] + segment['p_filesz']
|
|
#if end > file_size:
|
|
#raise ValueError('Underflow copying out the segment. File has %#x bytes left, segment end is %#x\n',
|
|
#file_size, end)
|
|
output[start - data_start:start - data_start + size] = (
|
|
segment.data()[offset:])
|
|
return ElfInfo(output, data_start, elf.header['e_entry'] + virt_to_phys,
|
|
mem_end - data_start)
|
|
|
|
def UpdateFile(infile, outfile, start_sym, end_sym, insert):
|
|
tout.notice("Creating file '%s' with data length %#x (%d) between symbols '%s' and '%s'" %
|
|
(outfile, len(insert), len(insert), start_sym, end_sym))
|
|
syms = GetSymbolFileOffset(infile, [start_sym, end_sym])
|
|
if len(syms) != 2:
|
|
raise ValueError("Expected two symbols '%s' and '%s': got %d: %s" %
|
|
(start_sym, end_sym, len(syms),
|
|
','.join(syms.keys())))
|
|
|
|
size = syms[end_sym].offset - syms[start_sym].offset
|
|
if len(insert) > size:
|
|
raise ValueError("Not enough space in '%s' for data length %#x (%d); size is %#x (%d)" %
|
|
(infile, len(insert), len(insert), size, size))
|
|
|
|
data = tools.read_file(infile)
|
|
newdata = data[:syms[start_sym].offset]
|
|
newdata += insert + tools.get_bytes(0, size - len(insert))
|
|
newdata += data[syms[end_sym].offset:]
|
|
tools.write_file(outfile, newdata)
|
|
tout.info('Written to offset %#x' % syms[start_sym].offset)
|
|
|
|
def read_loadable_segments(data):
|
|
"""Read segments from an ELF file
|
|
|
|
Args:
|
|
data (bytes): Contents of file
|
|
|
|
Returns:
|
|
tuple:
|
|
list of segments, each:
|
|
int: Segment number (0 = first)
|
|
int: Start address of segment in memory
|
|
bytes: Contents of segment
|
|
int: entry address for image
|
|
|
|
Raises:
|
|
ValueError: elftools is not available
|
|
"""
|
|
if not ELF_TOOLS:
|
|
raise ValueError("Python: No module named 'elftools'")
|
|
with io.BytesIO(data) as inf:
|
|
try:
|
|
elf = ELFFile(inf)
|
|
except ELFError as err:
|
|
raise ValueError(err)
|
|
entry = elf.header['e_entry']
|
|
segments = []
|
|
for i in range(elf.num_segments()):
|
|
segment = elf.get_segment(i)
|
|
if segment['p_type'] != 'PT_LOAD' or not segment['p_memsz']:
|
|
skipped = 1 # To make code-coverage see this line
|
|
continue
|
|
start = segment['p_offset']
|
|
rend = start + segment['p_filesz']
|
|
segments.append((i, segment['p_paddr'], data[start:rend]))
|
|
return segments, entry
|
|
|
|
def is_valid(data):
|
|
"""Check if some binary data is a valid ELF file
|
|
|
|
Args:
|
|
data (bytes): Bytes to check
|
|
|
|
Returns:
|
|
bool: True if a valid Elf file, False if not
|
|
"""
|
|
try:
|
|
DecodeElf(data, 0)
|
|
return True
|
|
except ELFError:
|
|
return False
|