glibc/scripts/move-symbol-to-libc.py

169 lines
5.6 KiB
Python

#!/usr/bin/python3
# Move symbols from other shared objects into libc.so.
# Copyright (C) 2020-2024 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
# <https://www.gnu.org/licenses/>.
"""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
# Make available glibc Python modules.
sys.path.append(os.path.dirname(os.path.realpath(__file__)))
import glibcsymbols
def add_to_libc_path(path, new_symbols):
"""Add SYMBOLS to the abilist file PATH.
NEW_SYMBOLS is a dictionary from glibcsymbols.VersionedSymbol
objects to their flags.
"""
original_symbols = glibcsymbols.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))
glibcsymbols.replace_file(
path, glibcsymbols.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 = glibcsymbols.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[glibcsymbols.VersionedSymbol(
placeholder, missing_version)] = 'F'
glibcsymbols.replace_file(
path, glibcsymbols.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:])