#!/usr/bin/env python3 # SPDX-License-Identifier: CC0-1.0 """\ Read .note.dlopen notes from ELF files and report the contents. """ import argparse import enum import functools import json import sys from elftools.elf.elffile import ELFFile from elftools.elf.sections import NoteSection try: import rich print_json = rich.print_json except ImportError: print_json = print def listify(f): def wrap(*args, **kwargs): return list(f(*args, **kwargs)) return functools.update_wrapper(wrap, f) class ELFFileReader: def __init__(self, filename): self.filename = filename self.elffile = ELFFile(open(filename, 'rb')) @functools.cache @listify def notes(self): for section in self.elffile.iter_sections(): if not isinstance(section, NoteSection) or section.name != '.note.dlopen': continue for note in section.iter_notes(): if note['n_type'] != 0x407c0c0a or note['n_name'] != 'FDO': continue note_desc = note['n_desc'] try: # On older Python versions (e.g.: Ubuntu 22.04) we get a string, on # newer versions a bytestring if not isinstance(note_desc, str): text = note_desc.decode('utf-8').rstrip('\0') else: text = note_desc.rstrip('\0') except UnicodeDecodeError as e: raise ValueError(f'{self.filename}: Invalid UTF-8 in .note.dlopen n_desc') from e try: j = json.loads(text) except json.JSONDecodeError as e: raise ValueError(f'{self.filename}: Invalid JSON in .note.dlopen note_desc') from e if not isinstance(j, list): print(f'{self.filename}: ignoring .note.dlopen n_desc with JSON that is not a list', file=sys.stderr) continue yield from j def dictify(f): def wrap(*args, **kwargs): return dict(f(*args, **kwargs)) return functools.update_wrapper(wrap, f) @dictify def group_by_soname(elffiles): for elffile in elffiles: for element in elffile.notes(): priority = element.get('priority', 'recommended') for soname in element['soname']: yield soname, priority class Priority(enum.Enum): suggested = 1 recommended = 2 required = 3 def __lt__(self, other): return self.value < other.value def group_by_feature(elffiles): features = {} # We expect each note to be in the format: # [ # { # "feature": "...", # "description": "...", # "priority": "required"|"recommended"|"suggested", # "soname": ["..."], # } # ] for elffiles in elffiles: for note in elffiles.notes(): prio = Priority[note.get('priority', 'recommened')] feature_name = note['feature'] try: feature = features[feature_name] except KeyError: # Create new feature = features[feature_name] = { 'description': note.get('description', ''), 'sonames': { soname:prio for soname in note['soname'] }, } else: # Merge if feature['description'] != note.get('description', ''): print(f"{note.filename}: feature {note['feature']!r} found with different description, ignoring", file=sys.stderr) for soname in note['soname']: highest = max(feature['sonames'].get(soname, Priority.suggested), prio) feature['sonames'][soname] = highest return features def filter_features(features, filter): if filter is None: return None ans = { name:feature for name,feature in features.items() if name in filter or not filter } if missing := set(filter) - set(ans): sys.exit('Some features not found:', ', '.join(missing)) return ans @listify def generate_rpm(elffiles, stanza, filter): # Produces output like: # Requires: libqrencode.so.4()(64bit) # Requires: libzstd.so.1()(64bit) for elffile in elffiles: suffix = '()(64bit)' if elffile.elffile.elfclass == 64 else '' for note in elffile.notes(): if note['feature'] in filter or not filter: soname = next(iter(note['soname'])) # we take the first — most recommended — soname yield f"{stanza}: {soname}{suffix}" def make_parser(): p = argparse.ArgumentParser( description=__doc__, allow_abbrev=False, add_help=False, epilog='If no option is specifed, --raw is the default.', ) p.add_argument( '-r', '--raw', action='store_true', help='Show the original JSON extracted from input files', ) p.add_argument( '-s', '--sonames', action='store_true', help='List all sonames and their priorities, one soname per line', ) p.add_argument( '-f', '--features', nargs='?', const=[], type=lambda s: s.split(','), action='extend', metavar='FEATURE1,FEATURE2', help='Describe features, can be specified multiple times', ) p.add_argument( '--rpm-requires', nargs='?', const=[], type=lambda s: s.split(','), action='extend', metavar='FEATURE1,FEATURE2', help='Generate rpm Requires for listed features', ) p.add_argument( '--rpm-recommends', nargs='?', const=[], type=lambda s: s.split(','), action='extend', metavar='FEATURE1,FEATURE2', help='Generate rpm Recommends for listed features', ) p.add_argument( 'filenames', nargs='+', metavar='filename', help='Library file to extract notes from', ) p.add_argument( '-h', '--help', action='help', help='Show this help message and exit', ) return p def parse_args(): args = make_parser().parse_args() if (not args.raw and not args.sonames and args.features is None and args.rpm_requires is None and args.rpm_recommends is None): # Make --raw the default if no action is specified. args.raw = True return args if __name__ == '__main__': args = parse_args() elffiles = [ELFFileReader(filename) for filename in args.filenames] features = group_by_feature(elffiles) if args.raw: for elffile in elffiles: print(f'# {elffile.filename}') print_json(json.dumps(elffile.notes(), indent=2)) if features_to_print := filter_features(features, args.features): print('# grouped by feature') print_json(json.dumps(features_to_print, indent=2, default=lambda prio: prio.name)) if args.rpm_requires is not None: lines = generate_rpm(elffiles, 'Requires', args.rpm_requires) print('\n'.join(lines)) if args.rpm_recommends is not None: lines = generate_rpm(elffiles, 'Recommends', args.rpm_recommends) print('\n'.join(lines)) if args.sonames: sonames = group_by_soname(elffiles) for soname in sorted(sonames.keys()): print(f"{soname} {sonames[soname]}")