trezor-agent/libagent/device/ui/pinentry.py

55 lines
1.5 KiB
Python

"""Python wrapper for GnuPG's pinentry."""
import logging
import os
import subprocess
import libagent.gpg.agent
log = logging.getLogger(__name__)
def write(p, line):
"""Send and flush a single line to the subprocess' stdin."""
log.debug('%s <- %r', p.args, line)
p.stdin.write(line)
p.stdin.flush()
def expect(p, prefixes):
"""Read a line and return it without required prefix."""
resp = p.stdout.readline()
log.debug('%s -> %r', p.args, resp)
for prefix in prefixes:
if resp.startswith(prefix):
return resp[len(prefix):]
raise ValueError('Unexpected response: {}'.format(resp))
def interact(description, binary, options):
"""Use GPG pinentry program to interact with the user."""
p = subprocess.Popen(args=[binary],
stdin=subprocess.PIPE,
stdout=subprocess.PIPE,
env=os.environ)
expect(p, [b'OK'])
description = libagent.gpg.agent.serialize(description.encode('ascii'))
write(p, b'SETDESC ' + description + b'\n')
expect(p, [b'OK'])
log.debug('setting %d options', len(options))
for opt in options:
write(p, b'OPTION ' + opt + b'\n')
expect(p, [b'OK', b'ERR'])
write(p, b'GETPIN\n')
pin = expect(p, [b'OK', b'D '])
p.communicate() # close stdin and wait for the process to exit
exit_code = p.wait()
if exit_code:
raise subprocess.CalledProcessError(exit_code, binary)
return pin.decode('ascii').strip()