mirror of
https://github.com/shadowsocks/shadowsocks-libev.git
synced 2026-10-21 14:33:55 +00:00
Max Lv
384810efce
* Make headers and leaf modules compile as C++
Wrap the declarations of every project header in extern "C" (after the
system includes, which must keep C++ linkage), so converted modules and
the remaining C files agree on linkage.
In the leaf modules, cast allocator and memchr results explicitly,
rename identifiers called new, replace the getpwnam_r VLA with the
fixed 16 KiB buffer the loop already capped itself at, and make the
rlimit initialiser conversion explicit. All of this is still valid C.
* Compile the leaf modules as C++
Rename base64, json, ipset, process, ppbloom, rule, ssurl and cache from
.c to .cpp without touching their contents, and update the CMake source
lists, debian/copyright and the docs.
Ported code keeps -Wall; -Wextra is now opt-in through
ss_strict_warnings() for code written as C++ (the core tests).
check_no_heap.py gains a ratchet baseline for the converted modules,
which still allocate the way the C code did. A new check_cxx_runtime
test verifies with nm that the programs and libshadowsocks-c.a still
need no C++ runtime library, so C consumers are unaffected.
* Fix the Windows branches of process.cpp for C++
Cast allocator results and the thread argument explicitly and
value-initialise JOBOBJECT_EXTENDED_LIMIT_INFORMATION with {}. Found by
the zig x86_64-windows-gnu cross build.
* Keep clang-tidy clean for the converted modules
Once the C headers are included from C++ translation units,
bugprone-dynamic-static-initializers reports each extern variable
declaration in them; none is defined in a header, so disable the check.
Mark the two bounded memchr searches in ssurl.cpp, which
bugprone-not-null-terminated-result misreads as string copies.
* check_cxx_runtime: ignore glibc symbol versions
nm on glibc prints __cxa_atexit@GLIBC_2.2.5, which the allowlist for the
libc-provided __cxa_atexit/__cxa_finalize did not match.
* Keep GCC's C++-only warnings off for modules converted from C
GCC's C++ -Wall includes -Wsign-compare and -Wclass-memaccess, which C's
-Wall does not, so the converted modules failed -Werror on GCC (Linux,
UCRT64) although nothing in them changed. They keep the warning set they
were written against; code under ss_strict_warnings() re-enables both.
68 lines
2.4 KiB
Python
68 lines
2.4 KiB
Python
#!/usr/bin/env python3
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# SPDX-License-Identifier: GPL-3.0-or-later
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"""Fail if programs or libraries need the C++ runtime library.
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The C++ core is built without exceptions or RTTI and uses only header-only
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parts of the standard library, so the programs and libshadowsocks-c stay
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consumable from plain C: a C program linking libshadowsocks-c.a must not need
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libstdc++ or libc++. This script lists the undefined symbols of each file with
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nm and rejects anything served by the C++ runtime (operator new/delete,
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exception and RTTI support, std:: functions).
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Usage: check_cxx_runtime.py [--nm NM] FILE...
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"""
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import argparse
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import re
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import shutil
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import subprocess
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import sys
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# Itanium-ABI names (with or without the Mach-O leading underscore) that only
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# the C++ runtime defines.
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RUNTIME = re.compile(
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r"^_?(?:"
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r"_Zn[wa]|_Zd[la]|" # operator new / delete
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r"_ZSt|_ZNSt|_ZNKSt|" # std:: functions and members
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r"_ZTI|_ZTS|_ZTV|" # typeinfo / vtables (RTTI, classes from the runtime)
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r"__cxa_(?!atexit$|finalize$|thread_atexit_impl$)|" # exception/guard support; libc owns these three
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r"__gxx_personality|_Unwind_|__dynamic_cast"
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r")"
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)
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def undefined_symbols(nm, path):
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result = subprocess.run([nm, "-u", path], capture_output=True, text=True)
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if result.returncode != 0:
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raise SystemExit(f"{nm} failed on {path}: {result.stderr.strip()}")
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symbols = set()
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for line in result.stdout.splitlines():
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line = line.strip()
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if not line or line.endswith(":"):
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continue # archive member headers
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# glibc nm prints versioned names (__cxa_atexit@GLIBC_2.2.5).
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symbols.add(line.split()[-1].split("@")[0])
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return symbols
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def main():
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parser = argparse.ArgumentParser(description=__doc__.splitlines()[0])
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parser.add_argument("--nm", default=shutil.which("nm") or "nm")
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parser.add_argument("files", nargs="+")
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args = parser.parse_args()
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failed = False
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for path in args.files:
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bad = sorted(s for s in undefined_symbols(args.nm, path) if RUNTIME.match(s))
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if bad:
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failed = True
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print(f"{path}: needs the C++ runtime:")
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for symbol in bad:
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print(f" {symbol}")
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else:
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print(f"{path}: ok")
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return 1 if failed else 0
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if __name__ == "__main__":
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sys.exit(main())
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