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