libfprint/tests/create-driver-test.py.in

#!/usr/bin/python3

BUILDDIR='@BUILDDIR@'
SRCDIR='@SRCDIR@'

import os
import sys
import signal
library_path = BUILDDIR + '/libfprint/'

# Relaunch ourselves with a changed environment so
# that we're loading the development version of libfprint
if 'LD_LIBRARY_PATH' not in os.environ or not library_path in os.environ['LD_LIBRARY_PATH']:
    os.environ['LD_LIBRARY_PATH'] = library_path
    os.environ['GI_TYPELIB_PATH'] = f'{BUILDDIR}/libfprint/'
    os.environ['FP_DEVICE_EMULATION'] = '1'
    try:
        os.execv(sys.argv[0], sys.argv)
    except Exception as e:
        print('Could not run script with new library path')
        sys.exit(1)

import gi
gi.require_version('FPrint', '2.0')
from gi.repository import FPrint

gi.require_version('GUsb', '1.0')
from gi.repository import GUsb

import re
import shutil
import subprocess
import tempfile
import time

def print_usage():
    print(f'Usage: {sys.argv[0]} driver [test-variant-name]')
    print('A test variant name is optional, and must be all lower case letters, or dashes, with no spaces')
    print(f'The captured data will be stored in {SRCDIR}/tests/[driver name]-[test variant name]')

if len(sys.argv) > 3:
    print_usage()
    sys.exit(1)

driver_name = sys.argv[1]
os.environ['FP_DRIVERS_WHITELIST'] = driver_name

test_variant = None
if len(sys.argv) == 3:
    valid_re = re.compile('[a-z-]*')
    test_variant = sys.argv[2]
    if (not valid_re.match(test_variant) or
        test_variant.startswith('-') or
        test_variant.endswith('-')):
        print(f'Invalid variant name {test_variant}\n')
        print_usage()
        sys.exit(1)

# Check that running as root

if os.geteuid() != 0:
    print(f'{sys.argv[0]} is expected to be run as root')
    sys.exit(1)

# Check that tshark is available

tshark = shutil.which('tshark')
if not tshark:
    print("The 'tshark' WireShark command-line tool must be installed to capture USB traffic")
    sys.exit(1)

# Find the fingerprint reader
ctx = FPrint.Context()
ctx.enumerate()
devices = ctx.get_devices()
if len(devices) == 0:
    print('Could not find a supported fingerprint reader')
    sys.exit(1)
elif len(devices) > 1:
    print('Capture requires a single supported fingerprint reader to be plugged in')
    sys.exit(1)

test_name = driver_name
if test_variant:
    test_name = driver_name + '-' + test_variant
usb_device = devices[0].get_property('fpi-usb-device')
bus_num = usb_device.get_bus()
device_num = usb_device.get_address()

print(f'### Detected USB device /dev/bus/usb/{bus_num:03d}/{device_num:03d}')

# Make directory

test_dir = SRCDIR + '/tests/' + test_name
os.makedirs(test_dir, mode=0o775, exist_ok=True)

# Capture device info

args = ['umockdev-record', f'/dev/bus/usb/{bus_num:03d}/{device_num:03d}']
device_out = open(test_dir + '/device', 'w')
process = subprocess.Popen(args, stdout=device_out)
process.wait()

# Run capture
# https://osqa-ask.wireshark.org/questions/53919/how-can-i-precisely-specify-a-usb-device-to-capture-with-tshark/

print(f'### Starting USB capture on usbmon{bus_num}')
capture_pid = os.fork()
assert(capture_pid >= 0)

unfiltered_cap_path = os.path.join(tempfile.gettempdir(), 'capture-unfiltered.pcapng')
if capture_pid == 0:
    os.setpgrp()
    args = ['tshark', '-q', '-i', f'usbmon{bus_num}', '-w', unfiltered_cap_path]
    os.execv(tshark, args)

# Wait 1 sec to settle (we can assume setpgrp happened)
time.sleep(1)

print('### Capturing fingerprint, please swipe or press your finger on the reader')
with subprocess.Popen(['python3', SRCDIR + '/tests/capture.py', test_dir + '/capture.png']) as capture_process:
    capture_process.wait()
    if capture_process.returncode != 0:
        print('Failed to capture fingerprint')
        os.killpg(capture_pid, signal.SIGKILL)
        sys.exit(1)

def t_waitpid(pid, timeout):
    timeout = time.time() + timeout
    r = os.waitpid(pid, os.WNOHANG)
    while timeout > time.time() and r[0] == 0:
        time.sleep(0.1)
        r = os.waitpid(pid, os.WNOHANG)

    return r

os.kill(capture_pid, signal.SIGTERM)
try:
    r = t_waitpid(capture_pid, 2)
    # Kill if nothing died
    if r[0] == 0:
        os.kill(capture_pid, signal.SIGKILL)
except ChildProcessError:
    pass

try:
    while True:
        r = t_waitpid(-capture_pid, timeout=2)
        # Kill the process group, if nothing died (and there are children)
        if r[0] == 0:
            os.killpg(capture_pid, signal.SIGKILL)
except ChildProcessError:
    pass

# Filter the capture
print(f'\n### Saving USB capture as test case {test_name}')
args = ['tshark', '-r', unfiltered_cap_path, '-Y', f'usb.bus_id == {bus_num} and usb.device_address == {device_num}',
        '-w', test_dir + '/capture.pcapng']
with subprocess.Popen(args, stderr=subprocess.DEVNULL) as filter_process:
    filter_process.wait()

print(f"\nDone! Don't forget to add {test_name} to tests/meson.build")