import filecmp import functools import hashlib import operator import os import os.path import shutil import subprocess import tempfile import types import urllib.parse import urllib.request import xml.dom.minidom from typing import ( Dict, Iterable, List, NewType, Tuple, ) Digest16 = NewType('Digest16', str) Digest32 = NewType('Digest32', str) class ChannelTableEntry(types.SimpleNamespace): digest: Digest16 file: str size: int url: str class Channel(types.SimpleNamespace): channel_html: bytes forwarded_url: str git_cachedir: str git_ref: str git_repo: str git_revision: str release_name: str table: Dict[str, ChannelTableEntry] url: str class VerificationError(Exception): pass class Verification: def __init__(self) -> None: self.line_length = 0 def status(self, s: str) -> None: print(s, end=' ', flush=True) self.line_length += 1 + len(s) # Unicode?? @staticmethod def _color(s: str, c: int) -> str: return '\033[%2dm%s\033[00m' % (c, s) def result(self, r: bool) -> None: message, color = {True: ('OK ', 92), False: ('FAIL', 91)}[r] length = len(message) cols = shutil.get_terminal_size().columns pad = (cols - (self.line_length + length)) % cols print(' ' * pad + self._color(message, color)) self.line_length = 0 if not r: raise VerificationError() def check(self, s: str, r: bool) -> None: self.status(s) self.result(r) def ok(self) -> None: self.result(True) def compare(a: str, b: str) -> Tuple[List[str], List[str], List[str]]: def throw(error: OSError) -> None: raise error def join(x: str, y: str) -> str: return y if x == '.' else os.path.join(x, y) def recursive_files(d: str) -> Iterable[str]: all_files: List[str] = [] for path, dirs, files in os.walk(d, onerror=throw): rel = os.path.relpath(path, start=d) all_files.extend(join(rel, f) for f in files) for dir_or_link in dirs: if os.path.islink(join(path, dir_or_link)): all_files.append(join(rel, dir_or_link)) return all_files def exclude_dot_git(files: Iterable[str]) -> Iterable[str]: return (f for f in files if not f.startswith('.git/')) files = functools.reduce( operator.or_, (set( exclude_dot_git( recursive_files(x))) for x in [a, b])) return filecmp.cmpfiles(a, b, files, shallow=False) def fetch(v: Verification, channel: Channel) -> None: v.status('Fetching channel') request = urllib.request.urlopen(channel.url, timeout=10) channel.channel_html = request.read() channel.forwarded_url = request.geturl() v.result(request.status == 200) v.check('Got forwarded', channel.url != channel.forwarded_url) def parse_channel(v: Verification, channel: Channel) -> None: v.status('Parsing channel description as XML') d = xml.dom.minidom.parseString(channel.channel_html) v.ok() v.status('Extracting release name:') title_name = d.getElementsByTagName( 'title')[0].firstChild.nodeValue.split()[2] h1_name = d.getElementsByTagName('h1')[0].firstChild.nodeValue.split()[2] v.status(title_name) v.result(title_name == h1_name) channel.release_name = title_name v.status('Extracting git commit:') git_commit_node = d.getElementsByTagName('tt')[0] channel.git_commit = git_commit_node.firstChild.nodeValue v.status(channel.git_commit) v.ok() v.status('Verifying git commit label') v.result(git_commit_node.previousSibling.nodeValue == 'Git commit ') v.status('Parsing table') channel.table = {} for row in d.getElementsByTagName('tr')[1:]: name = row.childNodes[0].firstChild.firstChild.nodeValue url = row.childNodes[0].firstChild.getAttribute('href') size = int(row.childNodes[1].firstChild.nodeValue) digest = Digest16(row.childNodes[2].firstChild.firstChild.nodeValue) channel.table[name] = ChannelTableEntry( url=url, digest=digest, size=size) v.ok() def digest_string(s: bytes) -> Digest16: return Digest16(hashlib.sha256(s).hexdigest()) def digest_file(filename: str) -> Digest16: hasher = hashlib.sha256() with open(filename, 'rb') as f: # pylint: disable=cell-var-from-loop for block in iter(lambda: f.read(4096), b''): hasher.update(block) return Digest16(hasher.hexdigest()) def to_Digest16(v: Verification, digest32: Digest32) -> Digest16: v.status('Converting digest to base16') process = subprocess.run( ['nix', 'to-base16', '--type', 'sha256', digest32], capture_output=True) v.result(process.returncode == 0) return Digest16(process.stdout.decode().strip()) def to_Digest32(v: Verification, digest16: Digest16) -> Digest32: v.status('Converting digest to base32') process = subprocess.run( ['nix', 'to-base32', '--type', 'sha256', digest16], capture_output=True) v.result(process.returncode == 0) return Digest32(process.stdout.decode().strip()) def fetch_with_nix_prefetch_url( v: Verification, url: str, digest: Digest16) -> str: v.status('Fetching %s' % url) process = subprocess.run( ['nix-prefetch-url', '--print-path', url, digest], capture_output=True) v.result(process.returncode == 0) prefetch_digest, path, empty = process.stdout.decode().split('\n') assert empty == '' v.check("Verifying nix-prefetch-url's digest", to_Digest16(v, Digest32(prefetch_digest)) == digest) v.status("Verifying file digest") file_digest = digest_file(path) v.result(file_digest == digest) return path def fetch_resources(v: Verification, channel: Channel) -> None: for resource in ['git-revision', 'nixexprs.tar.xz']: fields = channel.table[resource] url = urllib.parse.urljoin(channel.forwarded_url, fields.url) fields.file = fetch_with_nix_prefetch_url(v, url, fields.digest) v.status('Verifying git commit on main page matches git commit in table') v.result( open( channel.table['git-revision'].file).read(999) == channel.git_commit) def git_fetch(v: Verification, channel: Channel) -> None: # It would be nice if we could share the nix git cache, but as of the time # of writing it is transitioning from gitv2 (deprecated) to gitv3 (not ready # yet), and trying to straddle them both is too far into nix implementation # details for my comfort. So we re-implement here half of nix.fetchGit. # :( # TODO: Consider using pyxdg to find this path. channel.git_cachedir = os.path.expanduser( '~/.cache/nix-pin-channel/git/%s' % digest_string( channel.url.encode())) if not os.path.exists(channel.git_cachedir): v.status("Initializing git repo") process = subprocess.run( ['git', 'init', '--bare', channel.git_cachedir]) v.result(process.returncode == 0) v.status('Checking if we already have this rev:') process = subprocess.run( ['git', '-C', channel.git_cachedir, 'cat-file', '-e', channel.git_commit]) if process.returncode == 0: v.status('yes') if process.returncode == 1: v.status('no') v.result(process.returncode == 0 or process.returncode == 1) if process.returncode == 1: v.status('Fetching ref "%s"' % channel.git_ref) # We don't use --force here because we want to abort and freak out if forced # updates are happening. process = subprocess.run(['git', '-C', channel.git_cachedir, 'fetch', channel.git_repo, '%s:%s' % (channel.git_ref, channel.git_ref)]) v.result(process.returncode == 0) v.status('Verifying that fetch retrieved this rev') process = subprocess.run( ['git', '-C', channel.git_cachedir, 'cat-file', '-e', channel.git_commit]) v.result(process.returncode == 0) v.status('Verifying rev is an ancestor of ref') process = subprocess.run(['git', '-C', channel.git_cachedir, 'merge-base', '--is-ancestor', channel.git_commit, channel.git_ref]) v.result(process.returncode == 0) def check_channel_contents(v: Verification, channel: Channel) -> None: with tempfile.TemporaryDirectory() as channel_contents, \ tempfile.TemporaryDirectory() as git_contents: v.status('Extracting tarball %s' % channel.table['nixexprs.tar.xz'].file) shutil.unpack_archive( channel.table['nixexprs.tar.xz'].file, channel_contents) v.ok() v.status('Checking out corresponding git revision') git = subprocess.Popen(['git', '-C', channel.git_cachedir, 'archive', channel.git_commit], stdout=subprocess.PIPE) tar = subprocess.Popen( ['tar', 'x', '-C', git_contents, '-f', '-'], stdin=git.stdout) git.stdout.close() tar.wait() git.wait() v.result(git.returncode == 0 and tar.returncode == 0) v.status('Comparing channel tarball with git checkout') match, mismatch, errors = compare(os.path.join( channel_contents, channel.release_name), git_contents) v.ok() v.check('%d files match' % len(match), len(match) > 0) v.check('%d files differ' % len(mismatch), len(mismatch) == 0) expected_errors = [ '.git-revision', '.version-suffix', 'nixpkgs', 'programs.sqlite', 'svn-revision'] benign_errors = [] for ee in expected_errors: if ee in errors: errors.remove(ee) benign_errors.append(ee) v.check( '%d unexpected incomparable files' % len(errors), len(errors) == 0) v.check( '(%d of %d expected incomparable files)' % (len(benign_errors), len(expected_errors)), len(benign_errors) == len(expected_errors)) v.status('Removing temporary directories') v.ok() def main() -> None: v = Verification() channel = Channel(url='https://channels.nixos.org/nixos-20.03', git_repo='https://github.com/NixOS/nixpkgs.git', git_ref='nixos-20.03') fetch(v, channel) parse_channel(v, channel) fetch_resources(v, channel) git_fetch(v, channel) check_channel_contents(v, channel) print(channel) main()