From patchwork Fri May 15 13:47:08 2020 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Florian Weimer X-Patchwork-Id: 39257 Return-Path: X-Original-To: patchwork@sourceware.org Delivered-To: patchwork@sourceware.org Received: from server2.sourceware.org (localhost [IPv6:::1]) by sourceware.org (Postfix) with ESMTP id B5C0E3972474; Fri, 15 May 2020 13:47:22 +0000 (GMT) X-Original-To: libc-alpha@sourceware.org Delivered-To: libc-alpha@sourceware.org Received: from albireo.enyo.de (albireo.enyo.de [37.24.231.21]) by sourceware.org (Postfix) with ESMTPS id 7162B385DC0A for ; Fri, 15 May 2020 13:47:10 +0000 (GMT) DMARC-Filter: OpenDMARC Filter v1.3.2 sourceware.org 7162B385DC0A Authentication-Results: sourceware.org; dmarc=none (p=none dis=none) header.from=deneb.enyo.de Authentication-Results: sourceware.org; spf=pass smtp.mailfrom=fw@deneb.enyo.de Received: from [172.17.203.2] (helo=deneb.enyo.de) by albireo.enyo.de with esmtps (TLS1.3:ECDHE_RSA_AES_256_GCM_SHA384:256) id 1jZag8-00049O-9B for libc-alpha@sourceware.org; Fri, 15 May 2020 13:47:08 +0000 Received: from fw by deneb.enyo.de with local (Exim 4.92) (envelope-from ) id 1jZag8-00089I-5C for libc-alpha@sourceware.org; Fri, 15 May 2020 15:47:08 +0200 From: Florian Weimer To: libc-alpha@sourceware.org Subject: [PATCH v2] Add scripts/move-symbol-to-libc.py Date: Fri, 15 May 2020 15:47:08 +0200 Message-ID: <87imgx2tur.fsf@mid.deneb.enyo.de> MIME-Version: 1.0 X-Spam-Status: No, score=-12.3 required=5.0 tests=BAYES_00, GIT_PATCH_0, KAM_DMARC_STATUS, KAM_SHORT, KAM_STOCKGEN, SPF_HELO_NONE, SPF_PASS, TXREP autolearn=ham autolearn_force=no version=3.4.2 X-Spam-Checker-Version: SpamAssassin 3.4.2 (2018-09-13) on server2.sourceware.org X-BeenThere: libc-alpha@sourceware.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: Libc-alpha mailing list List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: libc-alpha-bounces@sourceware.org Sender: "Libc-alpha" This helper script can be used to move symbols to libc.abilist across all architectures, while preserving their symbol version. Reviewed-by: Adhemerval Zanella --- scripts/move-symbol-to-libc.py | 217 +++++++++++++++++++++++++++++++++++++++++ 1 file changed, 217 insertions(+) diff --git a/scripts/move-symbol-to-libc.py b/scripts/move-symbol-to-libc.py new file mode 100644 index 0000000000..4863c4dd8a --- /dev/null +++ b/scripts/move-symbol-to-libc.py @@ -0,0 +1,217 @@ +#!/usr/bin/python3 +# Move symbols from other shared objects into libc.so. +# Copyright (C) 2020 Free Software Foundation, Inc. +# This file is part of the GNU C Library. +# +# The GNU C Library is free software; you can redistribute it and/or +# modify it under the terms of the GNU Lesser General Public +# License as published by the Free Software Foundation; either +# version 2.1 of the License, or (at your option) any later version. +# +# The GNU C Library is distributed in the hope that it will be useful, +# but WITHOUT ANY WARRANTY; without even the implied warranty of +# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU +# Lesser General Public License for more details. +# +# You should have received a copy of the GNU Lesser General Public +# License along with the GNU C Library; if not, see +# . + +"""Move symbols from other shared objects into libc.so. + +This script moves ABI symbols from non-libc abilists in to +libc.abilist. Symbol versions are preserved. The script must be +called from the top of the glibc source tree. + +""" + +import argparse +import os.path +import sys + +def replace_file(path, new_contents): + """Atomically replace PATH with lines from NEW_CONTENTS. + + NEW_CONTENTS must be a sequence of strings. + + """ + temppath = path + 'T' + with open(temppath, 'w') as out: + for line in new_contents: + out.write(line) + os.rename(temppath, path) + +class VersionedSymbol: + """A combination of a symbol and its version.""" + + def __init__(self, symbol, version): + """Construct a new versioned symbol.""" + assert symbol + assert version + self.symbol = symbol + self.version = version + + def __str__(self): + return self.symbol + '@' + self.version + + def __eq__(self, other): + return self.symbol == other.symbol and self.version == other.version + + def __hash__(self): + return hash(self.symbol) ^ hash(self.version) + +def read_abilist(path): + """Read the abilist file at PATH. + + Return a dictionary from VersionedSymbols to their flags (as + strings). + + """ + result = {} + with open(path) as inp: + for line in inp: + version, symbol, flags = line.strip().split(' ', 2) + result[VersionedSymbol(symbol, version)] = flags + return result + +def abilist_lines(symbols): + """Build the abilist file contents (as a list of lines). + + SYMBOLS is a dictionary from VersionedSymbols to their flags. + + """ + result = [] + for versym, flags in symbols.items(): + result.append('{} {} {}\n'.format( + versym.version, versym.symbol, flags)) + result.sort() + return result + +def add_to_libc_path(path, new_symbols): + """Add SYMBOLS to the abilist file PATH. + + NEW_SYMBOLS is a dictionary from VersionedSymbols to their flags. + + """ + original_symbols = read_abilist(path) + updated_symbols = original_symbols.copy() + updated_symbols.update(new_symbols) + if updated_symbols != original_symbols: + sys.stdout.write('updating libc abilist {}\n'.format(path)) + replace_file(path, abilist_lines(updated_symbols)) + +# The name of the libc.so abilist file. +libc_abilist = 'libc.abilist' + +def add_to_libc_fallback(directory, subdirs, symbol_lines): + """Add SYMBOL_LINES to the libc.abilist files in SUBDIRS in DIRECTORY. + + All subdirectories must exist. If they do, return True. If not, + skip processing and return False. + + """ + abilists = [os.path.join(directory, subdir, libc_abilist) + for subdir in subdirs] + for abilist in abilists: + if not os.path.exists(abilist): + return False + for abilist in abilists: + add_to_libc_path(abilist, symbol_lines) + return True + +def add_to_libc(directory, symbol_lines): + + """Add SYMBOL_LINES (a list of strings) to libc.abilist in DIRECTORY. + + Try specific subdirectories as well if libc.abilist is not found + in DIRECTORY. + + """ + libc_path = os.path.join(directory, libc_abilist) + if os.path.exists(libc_path): + add_to_libc_path(libc_path, symbol_lines) + return + + # Special case for powerpc32 and mips32 variants. + if add_to_libc_fallback(directory, ('fpu', 'nofpu'), symbol_lines): + return + + # Special case for mips64. + if add_to_libc_fallback(directory, ('n32', 'n64'), symbol_lines): + return + + raise IOError('No libc.abilist found for: {}'.format(directory)) + +def move_symbols_1(path, to_move, moved_symbols): + """Move SYMBOLS from the abilist file PATH to MOVED_SYMBOLS. + + TO_MOVE must be a set of strings. MOVED_SYMBOLS is a dictionary. + + """ + suffix = '.abilist' + assert path.endswith('.abilist') + library = os.path.basename(path)[:-len(suffix)] + placeholder = '__{}_version_placeholder'.format(library) + + new_lines = [] + changed = False + + old_symbols = read_abilist(path) + old_versions = set(versym.version for versym in old_symbols.keys()) + matching_symbols = dict(e for e in old_symbols.items() + if e[0].symbol in to_move) + if matching_symbols: + sys.stdout.write('updating {} abilist {}\n'.format(library, path)) + new_symbols = dict(e for e in old_symbols.items() + if e[0].symbol not in to_move) + + # Add placeholder symbols to prevent symbol versions from + # going away completely. + new_versions = set(versym.version for versym in new_symbols.keys()) + for missing_version in old_versions - new_versions: + new_symbols[VersionedSymbol(placeholder, missing_version)] = 'F' + + replace_file(path, abilist_lines(new_symbols)) + + moved_symbols.update(matching_symbols) + +def move_symbols(directory, files, symbols): + """Move SYMBOLS from FILES (a list of abilist file names) in DIRECTORY. + + SYMBOLS must be a set of strings. + + """ + moved_symbols = {} + for filename in files: + move_symbols_1(os.path.join(directory, filename), symbols, + moved_symbols) + if moved_symbols: + add_to_libc(directory, moved_symbols) + +def get_parser(): + """Return an argument parser for this module.""" + parser = argparse.ArgumentParser(description=__doc__) + parser.add_argument('--only-linux', action='store_true', + help='Restrict the operation to Linux abilists') + parser.add_argument('symbols', help='name of the symbol to move', + nargs='+') + return parser + +def main(argv): + """The main entry point.""" + parser = get_parser() + opts = parser.parse_args(argv) + if opts.only_linux: + sysdeps = 'sysdeps/unix/sysv/linux' + else: + sysdeps = 'sysdeps' + + symbols = frozenset(opts.symbols) + + for directory, dirs, files in os.walk(sysdeps): + move_symbols(directory, [name for name in files + if name != 'libc.abilist' + and name.endswith('.abilist')], symbols) + +if __name__ == '__main__': + main(sys.argv[1:])