84 lines
2.6 KiB
Python
84 lines
2.6 KiB
Python
import io
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import os
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import re
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import sys
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from ._core import Process
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# FreeBSD: https://www.freebsd.org/cgi/man.cgi?query=procfs
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# NetBSD: https://man.netbsd.org/NetBSD-9.3-STABLE/mount_procfs.8
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# DragonFlyBSD: https://www.dragonflybsd.org/cgi/web-man?command=procfs
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BSD_STAT_PPID = 2
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# See https://docs.kernel.org/filesystems/proc.html
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LINUX_STAT_PPID = 3
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STAT_PATTERN = re.compile(r"\(.+\)|\S+")
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def detect_proc():
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"""Detect /proc filesystem style.
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This checks the /proc/{pid} directory for possible formats. Returns one of
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the following as str:
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* `stat`: Linux-style, i.e. ``/proc/{pid}/stat``.
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* `status`: BSD-style, i.e. ``/proc/{pid}/status``.
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"""
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pid = os.getpid()
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for name in ("stat", "status"):
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if os.path.exists(os.path.join("/proc", str(pid), name)):
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return name
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raise ProcFormatError("unsupported proc format")
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def _use_bsd_stat_format():
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try:
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return os.uname().sysname.lower() in ("freebsd", "netbsd", "dragonfly")
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except Exception:
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return False
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def _get_ppid(pid, name):
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path = os.path.join("/proc", str(pid), name)
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with io.open(path, encoding="ascii", errors="replace") as f:
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parts = STAT_PATTERN.findall(f.read())
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# We only care about TTY and PPID -- both are numbers.
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if _use_bsd_stat_format():
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return parts[BSD_STAT_PPID]
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return parts[LINUX_STAT_PPID]
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def _get_cmdline(pid):
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path = os.path.join("/proc", str(pid), "cmdline")
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encoding = sys.getfilesystemencoding() or "utf-8"
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with io.open(path, encoding=encoding, errors="replace") as f:
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# XXX: Command line arguments can be arbitrary byte sequences, not
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# necessarily decodable. For Shellingham's purpose, however, we don't
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# care. (pypa/pipenv#2820)
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# cmdline appends an extra NULL at the end, hence the [:-1].
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return tuple(f.read().split("\0")[:-1])
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class ProcFormatError(EnvironmentError):
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pass
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def iter_process_parents(pid, max_depth=10):
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"""Try to look up the process tree via the /proc interface."""
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stat_name = detect_proc()
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# Inner generator function so we correctly throw an error eagerly if proc
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# is not supported, rather than on the first call to the iterator. This
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# allows the call site detects the correct implementation.
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def _iter_process_parents(pid, max_depth):
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for _ in range(max_depth):
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ppid = _get_ppid(pid, stat_name)
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args = _get_cmdline(pid)
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yield Process(args=args, pid=pid, ppid=ppid)
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if ppid == "0":
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break
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pid = ppid
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return _iter_process_parents(pid, max_depth)
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