#!/usr/bin/env python
# -*- coding: utf-8 -*-

#    copyright 2008 by Christoph Höger <choeger@cs.tu-berlin.de>

#    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/>.


"""
  tracetrap will replace a executable with  a script that runs strace
  on it with the given outfile and the given strace arguments.
  The original file is saved as <NAME>.tracetrap and can be restored
  manually or via tracetrap --restore <FILENAME>
  This is usefull for sysadmins that want to strace processes that will 
  be started at an unpredictable point in time.
"""

import sys
import os
import getopt
import shutil

__version__ = "v0.2"

__usageString__ = """
usage:
  tracetrap.py --restore <PATH>
	Where <PATH> is the path to a trapped executable
or:	
  tracetrap.py OPTIONS
  Where OPTIONS consists of (optionals in [brackets])
					
  -e <PATH>,    --exe=<PATH>:        Path to executable to trap
  -l <PATH>,    --log=<PATH>:        Path to log file
  [-a <ARGS>,   --traceargs=<ARGS>   Extra arguments for strace]
  [-f <FILTER>, --filter=<FILTER>    Apply FILTER Expression to strace output]
  
"""

__trapstring__= """#!/usr/bin/env python
# -*- coding: utf-8 -*-
# trapped version. original is %(original)s

import sys
import os
import re

if __name__ == "__main__":
	argstr = ""
	for arg in sys.argv[1:]:
		argstr += " " + arg
	
	instr, out, err = os.popen3("strace %(straceargs)s %(original)s.tracetrap" + argstr)
	
	filter = "%(filter)s"
	regexpr = re.compile(filter)
	
	logfile = open("%(logfile)s","w")
	
	for line in err:
		if regexpr.match(line):
			logfile.write(line)
	
	logfile.close()
"""
class Args():
	def __init__(self):
			self.restore = False
			self.path = None
			self.log = None
			self.args = ""
			self.filter = ""

def about():
	print "tracetrap.py " + __version__
	print "2008 by Christoph Höger <choeger@cs.tu-berlin.de>"

def usage():
	print "usage: tracetrap.py [OPTIONS]"
	print __usageString__
	
def get_args():
	args = Args()	

	try:
			options, arguments = getopt.getopt(sys.argv[1:],"hvr:e:l:a:f:",
			["help","version","restore=","exe=","log=","traceargs=","filter="])
	except getopt.GetoptError, err:
		print "Options error: " + str(err)
		usage()
		sys.exit(1)
	
	for o, a in options:
		if o in ("-v", "--version"):
			about()
			sys.exit(0)
		elif o in ("-h", "--help"):
			usage()
			sys.exit(0)
		elif o in ("-r", "--restore"):
			args.restore = True
			args.path = a
		elif o in ("-r", "--restore"):
			args.restore = True
			args.path = a
		elif o in ("-e", "--exe"):
			args.path = a
		elif o in ("-l", "--log"):
			args.log = a
		elif o in ("-a", "--traceargs"):
			args.args = a
		elif  o in ("-f", "--filter"):
			args.filter = a
	
	return args
  
def restore(args):
	if (args.path):
		original = args.path + ".tracetrap"
		shutil.move(original, args.path)
	else:
		print("No path argument given!")
		sys.exit(1)

def setup_trap(args):
	if (not args.log):
		print "-l argument is required"
		sys.exit(1)
		
	if (args.path):
		shutil.move(args.path, args.path + ".tracetrap")
		outfile = open(args.path,"w")
		outfile.write(__trapstring__ % {'original' : args.path,
			'logfile':args.log, 'straceargs' : args.args, "filter" : args.filter})
		outfile.close()
		shutil.copymode(args.path + ".tracetrap", args.path)
	else:
		print "-e argument is required!"
		sys.exit(1)

if __name__ == "__main__":
	args = get_args()
	if (args.restore):
		restore(args)
	else:
		setup_trap(args)