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author | Biswakalyan Bhuyan <biswa@surgot.in> | 2022-11-13 23:46:45 +0530 |
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committer | Biswakalyan Bhuyan <biswa@surgot.in> | 2022-11-13 23:46:45 +0530 |
commit | 9468226a9e2e2ab8cdd599f1d8538e860ca86120 (patch) | |
tree | 0a77ada226d6db80639f96b438bf83e4e756edb5 /env/lib/python3.10/site-packages/packaging/_musllinux.py | |
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Diffstat (limited to 'env/lib/python3.10/site-packages/packaging/_musllinux.py')
-rw-r--r-- | env/lib/python3.10/site-packages/packaging/_musllinux.py | 136 |
1 files changed, 136 insertions, 0 deletions
diff --git a/env/lib/python3.10/site-packages/packaging/_musllinux.py b/env/lib/python3.10/site-packages/packaging/_musllinux.py new file mode 100644 index 0000000..8ac3059 --- /dev/null +++ b/env/lib/python3.10/site-packages/packaging/_musllinux.py @@ -0,0 +1,136 @@ +"""PEP 656 support. + +This module implements logic to detect if the currently running Python is +linked against musl, and what musl version is used. +""" + +import contextlib +import functools +import operator +import os +import re +import struct +import subprocess +import sys +from typing import IO, Iterator, NamedTuple, Optional, Tuple + + +def _read_unpacked(f: IO[bytes], fmt: str) -> Tuple[int, ...]: + return struct.unpack(fmt, f.read(struct.calcsize(fmt))) + + +def _parse_ld_musl_from_elf(f: IO[bytes]) -> Optional[str]: + """Detect musl libc location by parsing the Python executable. + + Based on: https://gist.github.com/lyssdod/f51579ae8d93c8657a5564aefc2ffbca + ELF header: https://refspecs.linuxfoundation.org/elf/gabi4+/ch4.eheader.html + """ + f.seek(0) + try: + ident = _read_unpacked(f, "16B") + except struct.error: + return None + if ident[:4] != tuple(b"\x7fELF"): # Invalid magic, not ELF. + return None + f.seek(struct.calcsize("HHI"), 1) # Skip file type, machine, and version. + + try: + # e_fmt: Format for program header. + # p_fmt: Format for section header. + # p_idx: Indexes to find p_type, p_offset, and p_filesz. + e_fmt, p_fmt, p_idx = { + 1: ("IIIIHHH", "IIIIIIII", (0, 1, 4)), # 32-bit. + 2: ("QQQIHHH", "IIQQQQQQ", (0, 2, 5)), # 64-bit. + }[ident[4]] + except KeyError: + return None + else: + p_get = operator.itemgetter(*p_idx) + + # Find the interpreter section and return its content. + try: + _, e_phoff, _, _, _, e_phentsize, e_phnum = _read_unpacked(f, e_fmt) + except struct.error: + return None + for i in range(e_phnum + 1): + f.seek(e_phoff + e_phentsize * i) + try: + p_type, p_offset, p_filesz = p_get(_read_unpacked(f, p_fmt)) + except struct.error: + return None + if p_type != 3: # Not PT_INTERP. + continue + f.seek(p_offset) + interpreter = os.fsdecode(f.read(p_filesz)).strip("\0") + if "musl" not in interpreter: + return None + return interpreter + return None + + +class _MuslVersion(NamedTuple): + major: int + minor: int + + +def _parse_musl_version(output: str) -> Optional[_MuslVersion]: + lines = [n for n in (n.strip() for n in output.splitlines()) if n] + if len(lines) < 2 or lines[0][:4] != "musl": + return None + m = re.match(r"Version (\d+)\.(\d+)", lines[1]) + if not m: + return None + return _MuslVersion(major=int(m.group(1)), minor=int(m.group(2))) + + +@functools.lru_cache() +def _get_musl_version(executable: str) -> Optional[_MuslVersion]: + """Detect currently-running musl runtime version. + + This is done by checking the specified executable's dynamic linking + information, and invoking the loader to parse its output for a version + string. If the loader is musl, the output would be something like:: + + musl libc (x86_64) + Version 1.2.2 + Dynamic Program Loader + """ + with contextlib.ExitStack() as stack: + try: + f = stack.enter_context(open(executable, "rb")) + except OSError: + return None + ld = _parse_ld_musl_from_elf(f) + if not ld: + return None + proc = subprocess.run([ld], stderr=subprocess.PIPE, universal_newlines=True) + return _parse_musl_version(proc.stderr) + + +def platform_tags(arch: str) -> Iterator[str]: + """Generate musllinux tags compatible to the current platform. + + :param arch: Should be the part of platform tag after the ``linux_`` + prefix, e.g. ``x86_64``. The ``linux_`` prefix is assumed as a + prerequisite for the current platform to be musllinux-compatible. + + :returns: An iterator of compatible musllinux tags. + """ + sys_musl = _get_musl_version(sys.executable) + if sys_musl is None: # Python not dynamically linked against musl. + return + for minor in range(sys_musl.minor, -1, -1): + yield f"musllinux_{sys_musl.major}_{minor}_{arch}" + + +if __name__ == "__main__": # pragma: no cover + import sysconfig + + plat = sysconfig.get_platform() + assert plat.startswith("linux-"), "not linux" + + print("plat:", plat) + print("musl:", _get_musl_version(sys.executable)) + print("tags:", end=" ") + for t in platform_tags(re.sub(r"[.-]", "_", plat.split("-", 1)[-1])): + print(t, end="\n ") |