From: Adhemerval Zanella via Libc-alpha <libc-alpha@sourceware.org>
To: libc-alpha@sourceware.org
Subject: Re: [PATCH v2] Add scripts/move-symbol-to-libc.py
Date: Wed, 5 Aug 2020 16:22:51 -0300 [thread overview]
Message-ID: <ceda8219-3edf-f1c6-3157-e615e3a65f11@linaro.org> (raw)
In-Reply-To: <87imgx2tur.fsf@mid.deneb.enyo.de>
On 15/05/2020 10:47, Florian Weimer wrote:
> This helper script can be used to move symbols to libc.abilist across
> all architectures, while preserving their symbol version.
LGTM, thanks.
Reviewed-by: Adhemerval Zanella <adhemerval.zanella@linaro.org>
>
> ---
> 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
> +# <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
> +
> +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)
Ok.
> +
> +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
Ok.
> +
> +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))
Ok.
> +
> +# 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
Ok.
> +
> +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))
Ok.
> +
> +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)
Ok.
> +
> +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)
Ok.
> +
> +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:])
>
Ok.
prev parent reply other threads:[~2020-08-05 19:23 UTC|newest]
Thread overview: 3+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-05-15 13:47 [PATCH v2] Add scripts/move-symbol-to-libc.py Florian Weimer
2020-08-05 7:24 ` Florian Weimer via Libc-alpha
2020-08-05 19:22 ` Adhemerval Zanella via Libc-alpha [this message]
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
List information: https://www.gnu.org/software/libc/involved.html
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=ceda8219-3edf-f1c6-3157-e615e3a65f11@linaro.org \
--to=libc-alpha@sourceware.org \
--cc=adhemerval.zanella@linaro.org \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for read-only IMAP folder(s) and NNTP newsgroup(s).