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#!/usr/bin/env python
#
# Copyright (c) 2008, Bjoern B. Brandenburg <bbb [at] cs.unc.edu>
#
# All rights reserved.
#
# Redistribution and use in source and binary forms, with or without
# modification, are permitted provided that the following conditions are met:
# * Redistributions of source code must retain the above copyright
# notice, this list of conditions and the following disclaimer.
# * Redistributions in binary form must reproduce the above copyright
# notice, this list of conditions and the following disclaimer in the
# documentation and/or other materials provided with the distribution.
# * Neither the name of the copyright holder nor the
# names of its contributors may be used to endorse or promote products
# derived from this software without specific prior written permission.
#
# THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
# AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
# IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
# ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE
# LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
# CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
# SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
# INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
# CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
# ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
# POSSIBILITY OF SUCH DAMAGE.
#
"""
Purpose: This tool displays the assembly code of all symbols matching a given
pattern in a given set of files. It is a quick&dirty wrapper around
the nm(1) and objdump(1) tools. Its main advantage is that it does not
require you to find out the addresses of a given set of symbols
manually. Also, it's considerably faster than just disassembling the
whole Linux kernel on slow systems.
Example: show_asm printk vmlinux
Disassemble printk-related functions in the Linux kernel.
show_asm 'main|foo|bar' *.o
Disassemble all main, foo, and bar
functions in all object files in the current directory.
"""
from subprocess import Popen, PIPE, call
import re
import sys
import os
NM_FORMAT = "([0-9a-f]+) *([0-9a-f]*) *([AaBbCcDdGgIiNnRrSsTtUuVvWw])" + \
" ([_a-zA-Z.0-9]+)"
nm_re = re.compile(NM_FORMAT)
def parse_nm_output(str):
"returns (start, length, type, name)"
m = nm_re.match(str)
if m:
start = int(m.group(1), 16)
if m.group(2) != '':
length = int(m.group(2), 16)
else:
length = 0
return (start, length, m.group(3), m.group(4))
else:
return None
def symbol_is_text(addr):
return addr[2] in "tT"
def nm(file):
cmd = "nm -S %s" % file
p = Popen(cmd, shell=True, stdout=PIPE)
return p.stdout
def nm_filtered(file, symbol):
cmd = "nm -S %s | egrep '%s' " % (file, symbol)
p = Popen(cmd, shell=True, stdout=PIPE)
return p.stdout
def objdump_symbol(file, addr):
objdump_cmd = "objdump -S -d --start-address=0x%x --stop-address=0x%x %s" \
% (addr[0], addr[0] + addr[1], file)
filter_cmd = "egrep -v 'Disassembly of|file format|^$'"
pipe_cmd = "%s | %s" % (objdump_cmd, filter_cmd)
print "=====[ %s:%s (0x%x - 0x%x, type: %s) ]=====" % \
(file, addr[3], addr[0], addr[0] + addr[1], addr[2])
sys.stdout.flush()
call(pipe_cmd, shell=True)
def get_address_ranges(file, symbol):
for line in nm_filtered(file, symbol):
addr = parse_nm_output(line)
if addr and addr[1] > 0 and symbol_is_text(addr):
objdump_symbol(file, addr)
if __name__ == "__main__":
if len(sys.argv) < 3:
name = os.path.basename(sys.argv[0])
print "Usage..: %s <symbol pattern> <object file>+" % name
print __doc__
else:
try:
for file in sys.argv[2:]:
get_address_ranges(file, sys.argv[1])
except KeyboardInterrupt:
print "Aborted."
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