firmware/shared/utils.py
2020-01-09 15:56:37 -05:00

251 lines
6.8 KiB
Python

# (c) Copyright 2018 by Coinkite Inc. This file is part of Coldcard <coldcardwallet.com>
# and is covered by GPLv3 license found in COPYING.
#
# utils.py - Misc utils. My favourite kind of source file.
#
import gc, sys, ustruct
from ubinascii import unhexlify as a2b_hex
from ubinascii import hexlify as b2a_hex
from ubinascii import a2b_base64, b2a_base64
class imported:
# Context manager that temporarily imports
# a list of modules.
# LATER: doubtful this saves any memory when all the code is frozen.
def __init__(self, *modules):
self.modules = modules
def __enter__(self):
# import everything required
rv = tuple(__import__(n) for n in self.modules)
return rv[0] if len(self.modules) == 1 else rv
def __exit__(self, exc_type, exc_value, traceback):
for n in self.modules:
if n in sys.modules:
del sys.modules[n]
# recovery that tasty memory.
gc.collect()
# class min_dramatic_pause:
# # insure that something takes at least N ms
# def __init__(self, min_time):
# import utime
#
# self.min_time = min_time
# self.start_time = utime.ticks_ms()
#
# def __enter__(self):
# pass
#
# def __exit__(self, exc_type, exc_value, traceback):
# import utime
#
# if exc_type is not None: return
#
# actual = utime.ticks_ms() - self.start_time
# if actual < self.min_time:
# utime.sleep_ms(self.min_time - actual)
#
def pretty_delay(n):
# decode # of seconds into various ranges, need not be precise.
if n < 120:
return '%d seconds' % n
n /= 60
if n < 60:
return '%d minutes' % n
n /= 60
if n < 48:
return '%.1f hours' % n
n /= 24
return 'about %d days' % n
def pretty_short_delay(sec):
# precise, shorter on screen display
if sec >= 3600:
return '%2dh %2dm %2ds' % (sec //3600, (sec//60) % 60, sec % 60)
else:
return '%2dm %2ds' % ((sec//60) % 60, sec % 60)
def pop_count(i):
# 32-bit population count for integers
# from <https://stackoverflow.com/questions/9829578>
i = i - ((i >> 1) & 0x55555555)
i = (i & 0x33333333) + ((i >> 2) & 0x33333333)
return (((i + (i >> 4) & 0xF0F0F0F) * 0x1010101) & 0xffffffff) >> 24
def get_filesize(fn):
# like os.path.getsize()
import uos
return uos.stat(fn)[6]
class HexWriter:
# Emulate a file/stream but convert binary to hex as they write
def __init__(self, fd):
self.fd = fd
def __enter__(self):
self.fd.__enter__()
return self
def __exit__(self, *a, **k):
self.fd.write(b'\r\n')
return self.fd.__exit__(*a, **k)
def write(self, b):
self.fd.write(b2a_hex(b))
class Base64Writer:
# Emulate a file/stream but convert binary to Base64 as they write
def __init__(self, fd):
self.fd = fd
self.runt = b''
def __enter__(self):
self.fd.__enter__()
return self
def __exit__(self, *a, **k):
if self.runt:
self.fd.write(b2a_base64(self.runt))
self.fd.write(b'\r\n')
return self.fd.__exit__(*a, **k)
def write(self, buf):
if self.runt:
buf = self.runt + buf
rl = len(buf) % 3
self.runt = buf[-rl:] if rl else b''
if rl < len(buf):
tmp = b2a_base64(buf[:(-rl if rl else None)])
# library puts in newlines!?
assert tmp[-1:] == b'\n', tmp
assert tmp[-2:-1] != b'=', tmp
self.fd.write(tmp[:-1])
def swab32(n):
# endian swap: 32 bits
return ustruct.unpack('>I', ustruct.pack('<I', n))[0]
def xfp2str(xfp):
# Standardized way to show an xpub's fingerprint... it's a 4-byte string
# and not really an integer. Used to show as '0x%08x' but that's wrong endian.
return b2a_hex(ustruct.pack('<I', xfp)).decode().upper()
def str2xfp(txt):
# Inverse of xfp2str
return ustruct.unpack('<I', a2b_hex(txt))[0]
def problem_file_line(exc):
# return a string of just the filename.py and line number where
# an exception occured. Best used on AssertionError.
import uio, sys, ure
tmp = uio.StringIO()
sys.print_exception(exc, tmp)
lines = tmp.getvalue().split('\n')[-3:]
del tmp
# convert:
# File "main.py", line 63, in interact
# into just:
# main.py:63
#
# on simulator, huge path is included, remove that too
rv = None
for ln in lines:
mat = ure.match(r'.*"(/.*/|)(.*)", line (.*), ', ln)
if mat:
try:
rv = mat.group(2) + ':' + mat.group(3)
except: pass
return rv or str(exc) or 'Exception'
def cleanup_deriv_path(bin_path):
# Clean-up path notation as string.
# - raise exceptions on junk
# - standardize on 'prime' notation (34' not 34p, or 34h)
# - assume 'm' prefix, so '34' becomes 'm/34', etc
# - do not assume /// is m/0/0/0
import ure
from public_constants import MAX_PATH_DEPTH
try:
s = str(bin_path, 'ascii').lower()
except UnicodeError:
raise AssertionError('must be ascii')
# empty string is valid
if s == '': return 'm'
s = s.replace('p', "'").replace('h', "'")
mat = ure.match(r"(m|m/|)[0-9/']*", s)
assert mat.group(0) == s, "invalid characters"
parts = s.split('/')
# the m/ prefix is optional
if parts and parts[0] == 'm':
parts = parts[1:]
if not parts:
# rather than: m/
return 'm'
assert len(parts) <= MAX_PATH_DEPTH, "too deep"
for p in parts:
assert p != '' and p != "'", "empty path component"
if p[-1] == "'":
p = p[0:-1]
try:
ip = int(p, 10)
except:
ip = -1
assert 0 <= ip < 0x80000000 and p == str(ip), "bad component: "+p
return 'm/' + '/'.join(parts)
class DecodeStreamer:
def __init__(self):
self.runt = bytearray()
def more(self, buf):
# Generator:
# - accumulate into mod-N groups
# - strip whitespace
for ch in buf:
if chr(ch).isspace(): continue
self.runt.append(ch)
if len(self.runt) == 128*self.mod:
yield self.a2b(self.runt)
self.runt = bytearray()
here = len(self.runt) - (len(self.runt) % self.mod)
if here:
yield self.a2b(self.runt[0:here])
self.runt = self.runt[here:]
class HexStreamer(DecodeStreamer):
# be a generator that converts hex digits into binary
# NOTE: mpy a2b_hex doesn't care about unicode vs bytes
mod = 2
def a2b(self, x):
return a2b_hex(x)
class Base64Streamer(DecodeStreamer):
# be a generator that converts Base64 into binary
mod = 4
def a2b(self, x):
return a2b_base64(x)
# EOF