#!/usr/bin/env python

import sys

import re

import getopt

import os

class Data:

    def __init__(self, data):

        self.data = data

class DebugData:

    class Item:

        def __init__(self):

            self.type = ''

            self.ref = 0

            self.level = 0

            self.attributes = {}

    def __init__(self, debug_filename):

        file = os.popen ('readelf -wi ' + debug_filename, 'r')

        self.__lines = file.readlines ()

        self.__current = 0

        self.__re1 = re.compile ('<([^>]+)><([^>]+)>:[^A]*Abbrev Number:.*\d+.*\((\w+)\)')

        self.__re2 = re.compile ('<[^>]+>[^D]*(DW_AT_\w+)([^:]*:)+ <?0?x?([^ \t><\)]+)[ >\t\)]*$')

        return

    def rewind (self):

        self.__current = 0

        return

    def read_line (self):

        if self.__current == len (self.__lines):

            return ''

        line = self.__lines[self.__current]

        self.__current = self.__current + 1

        return line

    def write_back_line (self):

        self.__current = self.__current - 1

        return

    def write_back_one (self, item):

        self.__current = self.__current - 1 - len (item.attributes.keys ())

        return

    def read_one (self):

        item = DebugData.Item ()

        while 1:

            line = self.read_line ()

            if line == '':

                if item.type == '':

                    return None

                else:

                    return item

            result = self.__re1.search (line)

            if result is None:

                continue

            item.level = result.group (1)

            item.ref = result.group (2)

            item.type = result.group (3)

            while 1:

                line = self.read_line ()

                result = self.__re1.search (line)

                if result is not None:

                    self.write_back_line ()

                    return item

                result = self.__re2.search (line)

                if result is None:

                    self.write_back_line ()

                    return item

                item.attributes[result.group (1)] = result.group (3)

        return item

    def find_struct (self, struct_type_name):

        return self.find_by_name ('DW_TAG_structure_type', struct_type_name)

    def find_by_name (self, type, name):

        item = self.read_one ()

        while item is not None:

            if item.type == type and \

                    item.attributes.has_key ('DW_AT_name') and \

                    item.attributes['DW_AT_name'] == name:

                return item

            item = self.read_one ()

        return item

    def find_by_ref (self, ref):

        item = self.read_one ()

        while item is not None:

            if item.ref == ref:

                return item

            item = self.read_one ()

        return item

    def find_member (self, member_name, parent):

        sub_item = self.read_one ()

        while sub_item is not None:

            if sub_item.level == parent.level:

                self.write_back_one ()

                return None

            if sub_item.type == 'DW_TAG_member' and \

                    sub_item.attributes.has_key ('DW_AT_name') and \

                    sub_item.attributes['DW_AT_name'] == member_name:

                return Data (sub_item.attributes['DW_AT_data_member_location'])

            sub_item = self.read_one ()

        return None

    # public methods below

    def get_struct_member_offset (self, struct_type_name, member_name):

        self.rewind ()

        item = self.find_struct (struct_type_name)

        if item is None:

            return None

        return self.find_member (member_name, item)

    def get_struct_size (self, struct_type_name):

        self.rewind ()

        item = self.find_struct (struct_type_name)

        if item is None:

            return None

        if not item.attributes.has_key ('DW_AT_byte_size'):

            return None

        return Data (item.attributes['DW_AT_byte_size'])    

    def get_typedef_member_offset (self, typename, member):

        self.rewind ()

        item = self.find_by_name ('DW_TAG_typedef', typename)

        if item is None:

            return None

        if not item.attributes.has_key ('DW_AT_type'):

            return None

        ref = item.attributes['DW_AT_type']

        self.rewind ()

        item = self.find_by_ref (ref)

        if item is None:

            return None

        return self.find_member (member, item)

class CouldNotFindFile:

    pass

def search_debug_file():

    files_to_try = ['/usr/lib64/debug/lib64/ld-2.11.2.so.debug',

                    '/usr/lib/debug/lib64/ld-linux-x86-64.so.2.debug',

                    '/usr/lib/debug/ld-linux-x86-64.so.2',

                    '/usr/lib/debug/lib/ld-linux.so.2.debug',

                    '/usr/lib/debug/ld-linux.so.2',

                    # ubuntu 1104/1110

                    '/usr/lib/debug/lib/i386-linux-gnu/ld-2.13.so',

                    '/usr/lib/debug/lib/x86_64-linux-gnu/ld-2.13.so',

                    # for ubuntu 0910. braindead

                    '/usr/lib/debug/lib/ld-2.10.1.so',

                    # for ubuntu 1004.

                    '/usr/lib/debug/lib/ld-2.11.1.so',

                    # for ubuntu 1010.

                    '/usr/lib/debug/lib/ld-2.12.1.so',

                    # ubuntu 1204

                    '/usr/lib/debug/lib/x86_64-linux-gnu/ld-2.15.so',

                    '/usr/lib/debug/lib/i386-linux-gnu/ld-2.15.so',

                    ]

    for file in files_to_try:

        if os.path.isfile (file):

            return file

    raise CouldNotFindFile ()

def list_lib_path():

    paths = []

    re_lib = re.compile ('(?<=^#)')

    for filename in os.listdir("/etc/ld.so.conf.d/"):

        for line in open ("/etc/ld.so.conf.d/" + filename, 'r'):

            if re_lib.search (line) is not None:

                continue

            paths.append(line.rstrip ())

    return ':'.join(paths)

def usage():

    print ''

def main(argv):

    config_filename = ''

    debug_filename = ''

    try:

        opts, args = getopt.getopt(argv, 'hc:d:',

                                   ['help', 'config=', 'debug='])

    except getopt.GetoptError:

        usage()

        sys.exit(2)

    for opt, arg in opts:

        if opt in ('-h', '--help'):

            usage()

            sys.exit()

        elif opt in ('-c', '--config'):

            config_filename = arg

        elif opt in ('-d', '--debug'):

            debug_filename = arg

    if config_filename != '':

        config = open (config_filename, 'w')

    else:

        config = sys.stdout

    if debug_filename == '':

        debug_filename = search_debug_file ()

    debug = DebugData (debug_filename)

    data = debug.get_struct_size ('rtld_global')

    if data is None:

        sys.exit (1)

    config.write ('#define CONFIG_RTLD_GLOBAL_SIZE ' + str(data.data) + '\n')

    data = debug.get_struct_size ('rtld_global_ro')

    if data is None:

        sys.exit (1)

    config.write ('#define CONFIG_RTLD_GLOBAL_RO_SIZE ' + str(data.data) + '\n')

    data = debug.get_struct_member_offset ('rtld_global_ro', '_dl_pagesize')

    if data is None:

        sys.exit (1)

    config.write ('#define CONFIG_RTLD_DL_PAGESIZE_OFFSET ' + str(data.data) + '\n')

    data = debug.get_struct_member_offset ('rtld_global', '_dl_error_catch_tsd')

    if data is None:

        sys.exit (1)

    config.write ('#define CONFIG_DL_ERROR_CATCH_TSD_OFFSET ' + str(data.data) + '\n')

    data = debug.get_struct_size ('pthread')

    if data is None:

        sys.exit (1)

    config.write ('#define CONFIG_TCB_SIZE ' + str(data.data) + '\n')

    data = debug.get_typedef_member_offset ('tcbhead_t', 'tcb')

    if data is None:

        sys.exit (1)

    config.write ('#define CONFIG_TCB_TCB_OFFSET ' + str(data.data) + '\n')

    data = debug.get_typedef_member_offset ('tcbhead_t', 'dtv')

    if data is None:

        sys.exit (1)

    config.write ('#define CONFIG_TCB_DTV_OFFSET ' + str(data.data) + '\n')

    data = debug.get_typedef_member_offset ('tcbhead_t', 'self')

    if data is None:

        sys.exit (1)

    config.write ('#define CONFIG_TCB_SELF_OFFSET ' + str(data.data) + '\n')

    data = debug.get_typedef_member_offset ('tcbhead_t', 'sysinfo')

    if data is None:

        sys.exit (1)

    config.write ('#define CONFIG_TCB_SYSINFO_OFFSET ' + str(data.data) + '\n')

    data = debug.get_typedef_member_offset ('tcbhead_t', 'stack_guard')

    if data is None:

        sys.exit (1)

    config.write ('#define CONFIG_TCB_STACK_GUARD ' + str(data.data) + '\n')

    config.write ('#define CONFIG_SYSTEM_LDSO_LIBRARY_PATH \"' + list_lib_path () + '\"\n')

if __name__ == "__main__":

    main(sys.argv[1:])