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#!/usr/bin/env python
#
# Copyright 2009 Free Software Foundation, Inc.
#
# This program is free software: you can redistribute it and/or modify
# it under the terms of the GNU General Public License as published by
# the Free Software Foundation, either version 3 of the License, or
# (at your option) any later version.
#
# This program is distributed in the hope that it will be useful,
# but WITHOUT ANY WARRANTY; without even the implied warranty of
# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
# GNU General Public License for more details.
#
# You should have received a copy of the GNU General Public License
# along with this program. If not, see <http://www.gnu.org/licenses/>.
#
import sys
import struct
from optparse import OptionParser
from pprint import pprint
import sbf
# see /usr/include/elf.h for the various magic values
_ehdr_fmt = ">16sHH5I6H"
_ehdr_fmt_size = struct.calcsize(_ehdr_fmt)
_phdr_fmt = ">8I"
_phdr_fmt_size = struct.calcsize(_phdr_fmt)
class elf32_ehdr(object):
def __init__(self, s):
(self.ident, self.type, self.machine, self.version, self.entry,
self.phoff, self.shoff, self.flags, self.ehsize,
self.phentsize, self.phnum, self.shentsize, self.shnum,
self.shstrndx) = struct.unpack(_ehdr_fmt, s)
class elf32_phdr(object):
def __init__(self, s):
(self.type, self.offset, self.vaddr, self.paddr,
self.filesz, self.memsz,
self.flags, self.align) = struct.unpack(_phdr_fmt, s)
def __repr__(self):
return "<elf32_phdr %s offset=%d paddr=0x%x, filesz=%d>" % (
p_type_str(self.type), self.offset, self.paddr, self.filesz)
def p_type_str(t):
if t <= 8:
return ('NULL', 'LOAD', 'DYNAMIC', 'INTERP', 'NOTE', 'SHLIB', 'PHDR', 'TLS', 'NUM')[t]
return "0x%x" % (t,)
def _get_ehdr(f):
if len(f) < _ehdr_fmt_size:
return False
ehdr = elf32_ehdr(f[0:_ehdr_fmt_size])
return ehdr
def elf32_big_endian_exec_p(f):
ehdr = _get_ehdr(f)
if not ehdr:
return False
#pprint(ehdr, sys.stderr)
e_ident = ehdr.ident
if not e_ident.startswith('\177ELF'):
return False
if (ord(e_ident[4]) != 1 # EI_CLASS == CLASS32
or ord(e_ident[5]) != 2 # EI_DATA == DATA2MSB
or ord(e_ident[6]) != 1 # EI_VERSION == EV_CURRENT
):
return False
if ehdr.type != 2: # e_type == ET_EXEC
return False
return True
# return (entry, (phdr, ...))
def get_elf32_prog_headers(f):
ehdr = _get_ehdr(f)
entry = ehdr.entry
phoff = ehdr.phoff
phentsize = ehdr.phentsize
phnum = ehdr.phnum
def extract(i):
start = phoff + i * phentsize
end = start + phentsize
return f[start:end]
return (entry, [elf32_phdr(extract(i)) for i in range(phnum)])
def main():
usage = "%prog: [options] elf_file"
parser = OptionParser()
parser.add_option("-o", "--output", default=None,
help="specify output filename [default=stdout]")
(options, args) = parser.parse_args()
if len(args) != 1:
parser.print_help()
sys.exit(1)
elf_file = open(args[0], 'rb')
elf_contents = elf_file.read()
if not elf32_big_endian_exec_p(elf_contents):
sys.stderr.write("%s: not a big-endian 32-bit ELF executable\n" % (args[0],))
sys.exit(1)
if options.output is None:
sbf_file = sys.stdout
else:
sbf_file = open(options.output, 'wb')
(entry, phdrs) = get_elf32_prog_headers(elf_contents)
#pprint(phdrs, sys.stderr)
def phdr_to_sec_desc(phdr):
target_addr = phdr.paddr
data = elf_contents[phdr.offset:phdr.offset+phdr.filesz]
#print >>sys.stderr, "pdhr_to_sec_desc:", (target_addr, data)
return sbf.sec_desc(target_addr, data)
sections = map(phdr_to_sec_desc, phdrs)
# pprint(sections, sys.stderr)
sbf.write_sbf(sbf_file, sbf.header(entry, sections))
if __name__ == '__main__':
main()
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