#!/usr/bin/env python

import os
import sys
import re
import datetime
import struct
import subprocess
import hashlib
import binascii
import shutil

""" Default / Architectural Options """

ARCHITECTURE = "amd64"

PAGESIZE = 4096
MEMORY_GAP = PAGESIZE

TCSSIZE = PAGESIZE
SSAFRAMESIZE = PAGESIZE
SSAFRAMENUM = 2

ENCLAVE_STACK_SIZE = PAGESIZE * 16
DEFAULT_ENCLAVE_SIZE = '256M'
DEFAULT_THREAD_NUM = 4
ENCLAVE_HEAP_MIN = 0x10000

""" Utilities """

def roundup(addr):
    remaining = addr % PAGESIZE
    if remaining:
        return addr + (PAGESIZE - remaining)
    else:
        return addr

def rounddown(addr):
    return addr - addr % PAGESIZE

def roundup_data(data):
    return data + '\0' * (roundup(len(data)) - len(data))

def int_to_bytes(i):
    b = ""
    l = 0
    while i > 0:
        b = b + chr(i % 256)
        i = i // 256
        l = l + 1
    return b

def bytes_to_int(b):
    i = 0
    for c in b:
        i = i * 256 + ord(c)
    return i

def parse_int(s):
    if len(s) > 2 and s.startswith("0x"):
        return int(s[2:], 16)
    if len(s) > 1 and s.startswith("0"):
        return int(s[1:], 8)
    return int(s)

def parse_size(s):
    scale = 1
    if s.endswith("K"):
        scale = 1024
    if s.endswith("M"):
        scale = 1024 * 1024
    if s.endswith("G"):
        scale = 1024 * 1024 * 1024
    if scale != 1:
        s = s[:-1]
    return parse_int(s) * scale


""" Reading / Writing Manifests """

def read_manifest(filename):
    manifest = dict()
    manifest_layout = []
    with open(filename, "r") as f:
        for line in f.readlines():
            if line == "":
                manifest_layout.append((None, None))
                break

            pound = line.find("#")
            if pound != -1:
                comment = line[pound:].strip()
                line = line[:pound]
            else:
                comment = None

            line = line.strip()
            equal = line.find("=")
            if equal != -1:
                key = line[:equal].strip()
                manifest[key] = line[equal + 1:].strip()
            else:
                key = None

            manifest_layout.append((key, comment))

    return (manifest, manifest_layout)

def output_manifest(filename, manifest, manifest_layout):
    with open(filename, 'w') as f:
        written = []

        for (key, comment) in manifest_layout:
            line = ''
            if key is not None:
                line += key + ' = ' + manifest[key]
                written.append(key)
            if comment is not None:
                if line != '':
                    line += ' '
                line += comment
            print >>f, line

        print >>f
        print >>f, "# Generated by Graphene"
        print >>f

        for key in sorted(manifest.keys()):
            if key not in written:
                print >>f, key, '=', manifest[key]


""" Loading Enclave Attributes """

def get_enclave_attributes(manifest):
    sgx_flags = {
        'FLAG_DEBUG'          : struct.pack("<Q", 0x02),
        'FLAG_MODE64BIT'      : struct.pack("<Q", 0x04),
    }

    sgx_xfrms = {
        'XFRM_LEGACY'         : struct.pack("<Q", 0x03),
        'XFRM_AVX'            : struct.pack("<Q", 0x06),
        'XFRM_AVX3'           : struct.pack("<Q", 0xe6),
        'XFRM_MPX'            : struct.pack("<Q", 0x18),
    }

    sgx_miscs = {
        'MISC_EXINFO'         : struct.pack("<L", 0x01),
    }

    default_attributes = [
        'FLAG_DEBUG',
        'XFRM_LEGACY',
        'XFRM_AVX',
    ]

    if ARCHITECTURE == 'amd64':
        default_attributes.append('FLAG_MODE64BIT')

    manifest_options = {
        'debug'          : 'FLAG_DEBUG',
        'enable_avx3'    : 'XFRM_AVX3',
        'enable_mpx'     : 'XFRM_MPX',
        'support_exinfo' : 'MISC_EXINFO',
    }

    attributes = default_attributes

    for opt in manifest_options.keys():
        key = 'sgx.' + opt
        if key in manifest:
            if manifest[key] == '1':
                attributes.append(manifest_options[opt])
            else:
                if manifest_options[opt] in attributes:
                    attributes.pop(manifest_options[opt])

    if manifest.get('sgx.disable_avx') == '1':
      attributes.remove('XFRM_AVX')

    flags_raw = struct.pack("<Q", 0)
    xfrms_raw = struct.pack("<Q", 0)
    miscs_raw = struct.pack("<L", 0)

    for attr in attributes:
        if attr in sgx_flags:
            flags_raw = ''.join([chr(ord(a)|ord(b)) for a, b in zip(flags_raw, sgx_flags[attr])])
        if attr in sgx_xfrms:
            xfrms_raw = ''.join([chr(ord(a)|ord(b)) for a, b in zip(xfrms_raw, sgx_xfrms[attr])])
        if attr in sgx_miscs:
            miscs_raw = ''.join([chr(ord(a)|ord(b)) for a, b in zip(miscs_raw, sgx_miscs[attr])])

    return flags_raw, xfrms_raw, miscs_raw


""" Generate Checksums / Measurement """

def resolve_uri(uri, check_exist=True):
    orig_uri = uri
    if uri.startswith('file:'):
        target = os.path.normpath(uri[5:])
    else:
        target = os.path.normpath(uri)
    if check_exist and not os.path.exists(target):
        raise Exception('Cannot resolve ' + orig_uri + ' or the file does not exist.')
    return target

builtin_checksum_dictionary = dict([
        ('libaprutil-1.so.0', '070ef5ce5bd2246b1422ee2629bf45520e0001b827355770fba695b3fa0875bd'),
        ('libprotobuf.so.9', 'abd8b868f0f06584c30edbee90e27e2f8546ffe5bbe938922f62c5821b243925'),
        ('php.ini', '64db864cdad432bf5ddd10147b862fcccbaeaa9f1946572e51fd29a40419d7a1'),
        ('libxml2.so.2', '7e4720faceaf360a182168cfa338bfd5756d794888ad6db022ffbddae5356536'),
        ('libstdc++.so.6', '62affc63ba79e6718ab4c4388ca85a73e9476eb5abe4b9af4ae26b79859d8a5f'),
        ('libgcc_s.so.1', 'c77f8044b4f8ae7166e5b0968204a4624529bfc4f42f29180ba62eccbb8ce8b5'),
        ('libphpcpp.so.2.0', '17fd518d703dc89e173aa7ac0da41aa9fa2c0c2aee53a347d018d86b0b9f2b7b'),
        ('localattestation_decryption.so', '6075d7bf84028a0ed356ce82b65d2c20687ac3ddf0b1f0ff377a4dde0fbff345'),
        ('ld-linux-x86-64.so.2', 'f4ca46938370886e67167be1918f9ee1542eb633e4baf802788ba3234b038bd1'),
        ('libnss_compat.so.2', '2264d94307147f686cd245da2e0a4be26d954cf49d4c67eb00e2351b727022e4'),
        ('libpthread.so.0', '08d37ac3e370c040d544ccc7c22b75856f00ba343396dcdf06b5894dca236965'),
        ('libpcre.so.3', '47e4aa7dbcc325bf87b9117d3e4d216a874ee547920068538f79d6a9aa2f8197'),
        ('libsysdb.so', '79719b196987aa45ebe03afcaaa4d20435bd18522f2879ccc8e05b95aac57fc4'),
        ('libc.so.6', 'a56b9bc1616be611cf6b0d198119a032dba5e0ab330f0bb45b6c507de9da1b11'),
        ('libexpat.so.1', 'c8a3bea5b20cef75b00fe195e6d5671916a1925b769e5506442fdc95292a11b9'),
        ('libnsl.so.1', 'ea9b08f38db8fa5767e8984643cbd418e9feb7c48795a216c9a610e3a06e7f2e'),
        ('libresolv.so.2', '975e49f2c5a49c5dc982f7f16c515f14d874454f4bea41839625785533e7a893'),
        ('libicudata.so.55', '7c08e87ad676f17e83e7966d7784bf00ca8a8801bb50f059d75f14a8724dd9c5'),
        ('libicuuc.so.55', '7f8317190f6bc783135b00f4058e21a67ece3b26f01c7fffec8fbd5dadcc4063'),
        ('libcrypt.so.1', '3fe988797911e25cb62afce73d416552d553f719233e41e7fec555e0bf1df8df'),
        ('libm.so.6', '7f5a011231b01dac0e42feaab47e86fdc98db636933502bd71cb0f71a8f860fa'),
        ('httpd', 'dd14c4876f1a42d91bf0607004df3bd7242ca7cd9f8436e1ae513ad7e923cf8e'),
        ('libdl.so.2', '3f35b33bf03edae233e453b16663c1955c6552e8226f37d4a67b5e55f5f19f12'),
        ('libnss_files.so.2', 'aa7f8780fa4d02b82d31e0e99d33fb809d440440d42eb8b2a9ef7b3675c37fc6'),
        ('liblzma.so.5', '0f59a1a9e0a369c403fa7fc3a5aa6fc92d3087bd9f9b9eb07da712f549553bbf'),
        ('libz.so.1', 'a04cab74df9c7f96f82b34286bda5d4ee810feaac92dd2e8bcfe931d9c8baef4'),
        ('libnss_nis.so.2', 'da420502ac3bfb7df0a52c5f5d282d030b069f420c354cb8c0b97be678bc0d16'),
        ('libapr-1.so.0', 'ed490fbee479638995c92abd0bb5129a4fde56a1d61982b087bc66383ac74b89'),
        ('libnss_dns.so.2', '95166d8666e6902b734354a66ebb9d9f69c20b04d912534cefcab47cec6e569b'),
        ('libuuid.so.1', 'd2427063179b81342bbd5179cdf6907928df78c24595c91cabd0624b853f45ae')
    ]);

def get_checksum(file): #Just need filename.
	key = file.split('/')[-1] 
	if key in builtin_checksum_dictionary:
        	return builtin_checksum_dictionary[key];
	raise Exception('Builtin dictionary doesnt know what this file is. Plz wait for a new version of the verifier.')


def get_trusted_files(manifest, args):
    targets = dict()

    if 'exec' in args:
        targets['exec'] = (args['exec'], resolve_uri(args['exec']))

    if 'loader.preload' in manifest:
        i = 0
        preloads = []
        for uri in str.split(manifest['loader.preload'], ','):
            targets['preload' + str(i)] = (uri, resolve_uri(uri))
            preloads.append(uri)
            i += 1

    for (key, val) in manifest.items():
        if not key.startswith('sgx.trusted_files.'):
            continue
        key = key[len('sgx.trusted_files.'):]
        if key in targets:
            raise Exception('repeated key in manifest: sgx.trusted_files.' + key)
        targets[key] = (val, resolve_uri(val))

    for (key, val) in targets.items():
        (uri, target) = val
        checksum = get_checksum(target) #.encode('hex')
        targets[key] = (uri, target, checksum)

    return targets

def get_trusted_children(manifest, args):
    targets = dict()

    for (key, val) in manifest.items():
        if not key.startswith('sgx.trusted_children.'):
            continue
        key = key[len('sgx.trusted_children.'):]
        if key in targets:
            raise Exception('repeated key in manifest: sgx.trusted_children.' + key)

        target = resolve_uri(val)
        sig = open(target, 'rb').read()[960:992].encode('hex')
        targets[key] = (val, target, sig)

    return targets

""" Populate Enclave Memory """

PAGEINFO_R = 0x1
PAGEINFO_W = 0x2
PAGEINFO_X = 0x4
PAGEINFO_TCS = 0x100
PAGEINFO_REG = 0x200

def get_loadcmds(filename):
    loadcmds = []
    p = subprocess.Popen(['readelf', '-l', '-W', filename],
            stdout=subprocess.PIPE,
            stderr=subprocess.PIPE)
    while True:
        line = p.stdout.readline()
        if line == '':
            break
        stripped = line.strip()
        if not stripped.startswith('LOAD'):
            continue
        tokens = stripped.split()
        if len(tokens) < 6:
            continue
        if len(tokens) >= 7 and tokens[7] == "E":
            tokens[6] += tokens[7]
        prot = 0
        for t in tokens[6]:
            if t == "R":
                prot = prot | 4
            if t == "W":
                prot = prot | 2
            if t == "E":
                prot = prot | 1

        loadcmds.append((int(tokens[1][2:], 16),  # offset
                         int(tokens[2][2:], 16),  # addr
                         int(tokens[4][2:], 16),  # filesize
                         int(tokens[5][2:], 16),  # memsize
                         prot))
    p.wait()
    if p.returncode != 0:
        return None
    return loadcmds

class MemoryArea:
    def __init__(self, desc, file=None, addr=None, size=None, flags=None):
        self.desc = desc
        self.file = file
        self.addr = addr
        self.size = size
        self.flags = flags
        self.is_binary = False

        if file:
            loadcmds = get_loadcmds(file)
            if loadcmds:
                mapaddr = 0xffffffffffffffff
                mapaddr_end = 0
                for (offset, addr, filesize, memsize, prot) in loadcmds:
                    if rounddown(addr) < mapaddr:
                        mapaddr = rounddown(addr)
                    if roundup(addr + memsize) > mapaddr_end:
                        mapaddr_end = roundup(addr + memsize)

                self.is_binary = True
                self.size = mapaddr_end - mapaddr
                if mapaddr > 0:
                    self.addr = mapaddr
            else:
                self.size = os.stat(file).st_size

        if self.addr is not None:
            self.addr = rounddown(self.addr)
        if self.size is not None:
            self.size = roundup(self.size)

def get_memory_areas(manifest, attr, args):
    areas = []
    areas.append(MemoryArea('ssa', size=attr['thread_num'] * SSAFRAMESIZE * SSAFRAMENUM,
                            flags=PAGEINFO_R|PAGEINFO_W|PAGEINFO_REG))
    areas.append(MemoryArea('tcs', size=attr['thread_num'] * TCSSIZE,
                            flags=PAGEINFO_TCS))
    areas.append(MemoryArea('tls', size=attr['thread_num'] * PAGESIZE,
                            flags=PAGEINFO_R|PAGEINFO_W|PAGEINFO_REG))

    for t in range(attr['thread_num']):
        areas.append(MemoryArea('stack', size=ENCLAVE_STACK_SIZE,
                                flags=PAGEINFO_R|PAGEINFO_W|PAGEINFO_REG))

    areas.append(MemoryArea('pal', file=args['libpal'], flags=PAGEINFO_REG))

    if 'exec' in args:
        areas.append(MemoryArea('exec', file=args['exec'],
                                flags=PAGEINFO_W|PAGEINFO_REG))
    return areas

def populate_memory_areas(manifest, attr, areas):
    populating = attr['enclave_size']

    for area in areas:
        if area.addr is not None:
            continue

        area.addr = populating - area.size
        if area.addr < ENCLAVE_HEAP_MIN:
            raise Exception("Enclave size is not large enough")
        if area.desc == 'exec':
            populating = area.addr;
        else:
            populating = area.addr - MEMORY_GAP

    free_areas = []
    for area in areas:
        if area.addr + area.size < populating:
            addr = area.addr + area.size
            free_areas.append(MemoryArea('free', addr=addr, size=populating - addr,
                                flags=PAGEINFO_R|PAGEINFO_W|PAGEINFO_X|PAGEINFO_REG))
            populating = area.addr

    if populating > ENCLAVE_HEAP_MIN:
        free_areas.append(MemoryArea('free', addr=ENCLAVE_HEAP_MIN,
                                     size=populating - ENCLAVE_HEAP_MIN,
                                     flags=PAGEINFO_R|PAGEINFO_W|PAGEINFO_X|PAGEINFO_REG))

    return areas + free_areas

def generate_measurement(attr, areas):

    def do_ecreate(digest, size):
        data = struct.pack("<8sLQ44s", "ECREATE", SSAFRAMESIZE / PAGESIZE, size, "")
        digest.update(data)

    def do_eadd(digest, offset, flags):
        data = struct.pack("<8sQQ40s", "EADD", offset, flags, "")
        digest.update(data)

    def do_eextend(digest, offset):
        data = struct.pack("<8sQ48s", "EEXTEND", offset, "")
        digest.update(data)

    class mrenclave_digest:
        def __init__(self):
            self.digest = hashlib.sha256()

        def update(self, payload):
            for er in range(0, len(payload), 64):
                self.digest.update(payload[er:er+64])

        def finalize(self):
            return self.digest.digest()

    mrenclave = mrenclave_digest()
    do_ecreate(mrenclave, attr['enclave_size'])

    def print_area(addr, size, flags, desc, measured):
        if flags & PAGEINFO_REG:
            type = 'REG'
        if flags & PAGEINFO_TCS:
            type = 'TCS'
        prot = ['-', '-', '-']
        if flags & PAGEINFO_R:
            prot[0] = 'R'
        if flags & PAGEINFO_W:
            prot[1] = 'W'
        if flags & PAGEINFO_X:
            prot[2] = 'X'
        prot = ''.join(prot)

        desc = '(' + desc + ')'
        if measured:
            desc += ' measured'

        if size == PAGESIZE:
            print >>sys.stderr, "    %016x [%s:%s] %s" % (addr, type, prot, desc)
        else:
            print >>sys.stderr, "    %016x-%016lx [%s:%s] %s" % (addr, addr + size, type, prot, desc)

    def load_file(digest, f, offset, addr, filesize, memsize, desc, flags):
        f_addr = rounddown(offset)
        m_addr = rounddown(addr)
        f_size = roundup(offset + filesize) - f_addr
        m_size = roundup(addr + memsize) - m_addr

        print_area(m_addr, f_size, flags, desc, True)
        if f_size < m_size:
            print_area(m_addr + f_size, m_size - f_size, flags, "bss", False)

        for pg in range(m_addr, m_addr + m_size, PAGESIZE):
            do_eadd(digest, pg, flags)

            if (pg >= m_addr + f_size):
                continue

            for er in range(pg, pg + PAGESIZE, 256):
                do_eextend(digest, er)
                start = er - m_addr + f_addr
                end = start + 256
                start_zero = ""
                if start < offset:
                    if offset - start >= 256:
                        start_zero = chr(0) * 256
                    else:
                        start_zero = chr(0) * (offset - start)
                end_zero = ""
                if end > offset + filesize:
                    if end - offset - filesize >= 256:
                        end_zero = chr(0) * 256
                    else:
                        end_zero = chr(0) * (end - offset - filesize)
                start += len(start_zero)
                end -= len(end_zero)
                if start < end:
                    f.seek(start)
                    data = f.read(end - start)
                else:
                    data = ""
                if len(start_zero + data + end_zero) != 256:
                    raise Exception("wrong calculation")
                digest.update(start_zero + data + end_zero)

    for area in areas:
        if area.file:
            with open(area.file, 'rb') as f:
                if area.is_binary:
                    loadcmds = get_loadcmds(area.file)
                    if loadcmds:
                        mapaddr = 0xffffffffffffffff
                        for (offset, addr, filesize, memsize, prot) in loadcmds:
                            if rounddown(addr) < mapaddr:
                                mapaddr = rounddown(addr)
                    baseaddr = area.addr - mapaddr
                    for (offset, addr, filesize, memsize, prot) in loadcmds:
                        flags = area.flags
                        if prot & 4:
                            flags = flags | PAGEINFO_R
                        if prot & 2:
                            flags = flags | PAGEINFO_W
                        if prot & 1:
                            flags = flags | PAGEINFO_X

                        if flags & PAGEINFO_X:
                            desc = 'code'
                        else:
                            desc = 'data'
                        load_file(mrenclave, f, offset, baseaddr + addr,
                                  filesize, memsize, desc, flags)
                else:
                    load_file(mrenclave, f, 0, area.addr,
                              os.stat(area.file).st_size, area.size,
                              area.desc, area.flags)
        else:
            for a in range(area.addr, area.addr + area.size, PAGESIZE):
                do_eadd(mrenclave, a, area.flags)
            print_area(area.addr, area.size, area.flags, area.desc, False)

    return mrenclave.finalize()

""" Generate Sigstruct """

def generate_sigstruct(attr, args, mrenclave):
    today = datetime.date.today()

    # field format: (offset, type, value)
    fields = dict()

    fields['header']    = (   0, "<4L",  0x00000006, 0x000000e1, 0x00010000, 0x00000000)
    fields['vendor']    = (  16, "<L",   0x00000000)
    fields['date']      = (  20, "<HBB", today.year, today.month, today.day)
    fields['header2']   = (  24, "<4L",  0x00000101, 0x00000060, 0x00000060, 0x00000001)
    fields['swdefined'] = (  40, "<L",   0x00000000)

    fields['miscs']     = ( 900, "4s",   attr['miscs'])
    fields['miscmask']  = ( 904, "4s",   attr['miscs'])
    fields['attrs']     = ( 928, "8s8s", attr['flags'], attr['xfrms'])
    fields['attrmask']  = ( 944, "8s8s", attr['flags'], attr['xfrms'])
    fields['mrencalve'] = ( 960, "32s",  mrenclave)
    fields['isvprodid'] = (1024, "<H",   attr['isvprodid'])
    fields['isvsvn']    = (1026, "<H",   attr['isvsvn'])

    sign_buffer = bytearray(128 + 128)

    for key, field in fields.items():
        if field[0] >= 900:
            struct.pack_into(field[1], sign_buffer, field[0] - 900 + 128, *field[2:])
        else:
            struct.pack_into(field[1], sign_buffer, field[0], *field[2:])
	#TODO: Got to work on this part now - take in a key
    p = subprocess.Popen(['openssl', 'rsa', '-modulus', '-in', args['key'], '-noout'], stdout=subprocess.PIPE)
    modulus_out = p.communicate()[0]
    modulus = modulus_out[8:8+384*2].lower().decode('hex')
    modulus = modulus[::-1]
	#TODO: Sign the manifest. Prolly do this in C code? 
    p = subprocess.Popen(['openssl', 'sha256', '-binary', '-sign', args['key']],
            stdin=subprocess.PIPE, stdout=subprocess.PIPE)
    signature = p.communicate(sign_buffer)[0]
    signature = signature[::-1]

    def bytes_to_int(bytes):
        i = 0
        q = 1
        for digit in bytes:
            if ord(digit) != 0:
                i = i + ord(digit) * q
            q = q * 256
        return i

    def int_to_bytes(i):
        b = ""
        l = 0
        while i > 0:
            b = b + chr(i % 256)
            i = i // 256
            l = l + 1
        return b

    modulus_int = bytes_to_int(modulus)
    signature_int = bytes_to_int(signature)

    tmp1   = signature_int * signature_int
    q1_int = tmp1 // modulus_int
    tmp2   = tmp1 % modulus_int
    q2_int = tmp2 * signature_int // modulus_int

    q1 = int_to_bytes(q1_int)
    q2 = int_to_bytes(q2_int)

    fields['modulus']   = ( 128, "384s", modulus)
    fields['exponent']  = ( 512, "<L",   3)
    fields['signature'] = ( 516, "384s", signature)

    fields['q1']        = (1040, "384s", q1)
    fields['q2']        = (1424, "384s", q2)

    buffer = bytearray(1808)

    for key, field in fields.items():
        struct.pack_into(field[1], buffer, field[0], *field[2:])

    return buffer

""" Main Program """

options = {
#       Option name : (Required  Value)
        'output':    (True,    'output'),
        'libpal':    (True,    'libpal path'),
        'key':       (True,    'signing key'),
        'manifest':  (True,    'manifest'),
        'exec':      (False,   'executable'),
    }

def usage():
    usage_message = 'USAGE: ' + sys.argv[0] + ' -help|-h'

    for opt, optval in options.items():
        if not optval[0]:
            usage_message += '['
        usage_message += '|-' + opt
        if optval[1]:
            usage_message += ' <' + optval[1] + '>'
        if not optval[0]:
            usage_message += ']'

    print >> sys.stderr, usage_message
    os._exit(-1)

def parse_args():
    args = dict()
    for opt, optval in options.items():
        if not optval[1]:
            args[opt] = False

    i = 1
    while i < len(sys.argv):
        got = sys.argv[i]

        if got == '-help' or got == '-h':
            usage()

        invalid = True
        for opt, optval in options.items():
            if got != '-' + opt:
                continue

            if optval[1] is not None:
                i += 1
                if i == len(sys.argv):
                    print >>sys.stderr, "Option %s needs a value." % (opt)
                    usage()
                args[opt] = sys.argv[i]
            else:
                args[opt] = True

            invalid = False
            break

        if invalid:
            print >>sys.stderr, "Unknown option: %s." % (got[1:])
            usage()
        i += 1

    for opt, optval in options.items():
        if optval[0] and opt not in args:
            print >>sys.stderr, "Must specify %s <%s>." % (opt, optval[1])
            usage()

    return args

if __name__ == "__main__":

    # Parse arguments
    args = parse_args()

    (manifest, manifest_layout) = read_manifest(args['manifest'])

    if 'exec' not in args:
        if 'loader.exec' in manifest:
            exec_url = manifest['loader.exec']
            if exec_url[:5] != 'file:':
                print "executable must be a local file"
                os._exit(-1)

            args['exec'] = os.path.join(os.path.dirname(args['manifest']), exec_url[5:])

    args['root'] = os.path.dirname(os.path.abspath(args['output']))

    if 'sgx.sigfile' in manifest:
        args['sigfile'] = resolve_uri(manifest['sgx.sigfile'], False)
    else:
        sigfile = args['output']
        for ext in ['.manifest.sgx', '.manifest']:
            if sigfile.endswith(ext):
                sigfile = sigfile[:-len(ext)]
                break
        args['sigfile'] = sigfile + '.sig'
        manifest['sgx.sigfile'] = 'file:' + os.path.basename(args['sigfile'])

    # Get attributes from manifest
    attr = dict()

    for key, default, parse in [
        ('enclave_size', DEFAULT_ENCLAVE_SIZE,    parse_size),
        ('thread_num',   str(DEFAULT_THREAD_NUM), parse_int),
        ('isvprodid',    '0',                     parse_int),
        ('isvsvn',       '0',                     parse_int),
    ]:
        if 'sgx.' + key not in manifest:
            manifest['sgx.' + key] = default
        attr[key] = parse(manifest['sgx.' + key])

    (attr['flags'], attr['xfrms'], attr['miscs']) = get_enclave_attributes(manifest)

    print >>sys.stderr, "Attributes:"
    print >>sys.stderr, "    size:      %d" % (attr['enclave_size'])
    print >>sys.stderr, "    threadnum: %d" % (attr['thread_num'])
    print >>sys.stderr, "    isvprodid: %d" % (attr['isvprodid'])
    print >>sys.stderr, "    isvsvn:    %d" % (attr['isvsvn'])
    print >>sys.stderr, "    flags:     %016x" % (bytes_to_int(attr['flags']))
    print >>sys.stderr, "    xfrms:     %016x" % (bytes_to_int(attr['xfrms']))
    print >>sys.stderr, "    miscs:     %08x"  % (bytes_to_int(attr['miscs']))

    # Get trusted checksums and measurements
	#Fixed this to make it run without computing hashes. 
    print >>sys.stderr, "Trusted files:"
    for key, val in get_trusted_files(manifest, args).items():
        (uri, target, checksum) = val
        print >>sys.stderr, "    ('%s', '%s')," % (target.split('/')[-1], checksum) #(checksum, uri)
        manifest['sgx.trusted_checksum.' + key] = checksum

    print >>sys.stderr, "Trusted children:"
    for key, val in get_trusted_children(manifest, args).items():
        (uri, target, mrenclave) = val
        print >>sys.stderr, "    %s %s" % (mrenclave, uri)
        manifest['sgx.trusted_mrenclave.' + key] = mrenclave

	#TODO: Uses readelf for .sgx manifest file, output file and libpal. 
	#Try to hard-code results for libpal, exec in GET_LOADCMDS (called by the constructor of MemoryAreas).
    # Try populate memory areas
    memory_areas = get_memory_areas(manifest, attr, args)

    if len([a for a in memory_areas if a.addr is not None]) > 0:
        manifest['sgx.static_address'] = '1'
    else:
        ENCLAVE_HEAP_MIN = 0

    # Add manifest at the top
    shutil.copy2(args['manifest'], args['output'])
    output_manifest(args['output'], manifest, manifest_layout)

    memory_areas = [
            MemoryArea('manifest', file=args['output'],
                       flags=PAGEINFO_R|PAGEINFO_REG)
            ] + memory_areas

    memory_areas = populate_memory_areas(manifest, attr, memory_areas)

    print >>sys.stderr, "Memory:"
    # Generate measurement
	#TODO:This should also tap into the hard-coded readelf results. 
    mrenclave = generate_measurement(attr, memory_areas)

    print >>sys.stderr, "Measurement:"
    print >>sys.stderr, "    " + mrenclave.encode('hex')

	#TODO:This should also be removed - prolly just return the sigstruct to the main verifier enclave. 
    # Generate sigstruct
    open(args['sigfile'], 'wb').write(generate_sigstruct(attr, args, mrenclave))