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1# Copyright (c) 2009, Giampaolo Rodola'. All rights reserved.
2# Use of this source code is governed by a BSD-style license that can be
3# found in the LICENSE file.
5"""Routines common to all posix systems."""
7import enum
8import glob
9import os
10import signal
11import time
13from ._common import MACOS
14from ._common import TimeoutExpired
15from ._common import memoize
16from ._common import sdiskusage
17from ._common import usage_percent
19if MACOS:
20 from . import _psutil_osx
23__all__ = ['pid_exists', 'wait_pid', 'disk_usage', 'get_terminal_map']
26def pid_exists(pid):
27 """Check whether pid exists in the current process table."""
28 if pid == 0:
29 # According to "man 2 kill" PID 0 has a special meaning:
30 # it refers to <<every process in the process group of the
31 # calling process>> so we don't want to go any further.
32 # If we get here it means this UNIX platform *does* have
33 # a process with id 0.
34 return True
35 try:
36 os.kill(pid, 0)
37 except ProcessLookupError:
38 return False
39 except PermissionError:
40 # EPERM clearly means there's a process to deny access to
41 return True
42 # According to "man 2 kill" possible error values are
43 # (EINVAL, EPERM, ESRCH)
44 else:
45 return True
48Negsignal = enum.IntEnum(
49 'Negsignal', {x.name: -x.value for x in signal.Signals}
50)
53def negsig_to_enum(num):
54 """Convert a negative signal value to an enum."""
55 try:
56 return Negsignal(num)
57 except ValueError:
58 return num
61def wait_pid(
62 pid,
63 timeout=None,
64 proc_name=None,
65 _waitpid=os.waitpid,
66 _timer=getattr(time, 'monotonic', time.time), # noqa: B008
67 _min=min,
68 _sleep=time.sleep,
69 _pid_exists=pid_exists,
70):
71 """Wait for a process PID to terminate.
73 If the process terminated normally by calling exit(3) or _exit(2),
74 or by returning from main(), the return value is the positive integer
75 passed to *exit().
77 If it was terminated by a signal it returns the negated value of the
78 signal which caused the termination (e.g. -SIGTERM).
80 If PID is not a children of os.getpid() (current process) just
81 wait until the process disappears and return None.
83 If PID does not exist at all return None immediately.
85 If *timeout* != None and process is still alive raise TimeoutExpired.
86 timeout=0 is also possible (either return immediately or raise).
87 """
88 if pid <= 0:
89 # see "man waitpid"
90 msg = "can't wait for PID 0"
91 raise ValueError(msg)
92 interval = 0.0001
93 flags = 0
94 if timeout is not None:
95 flags |= os.WNOHANG
96 stop_at = _timer() + timeout
98 def sleep(interval):
99 # Sleep for some time and return a new increased interval.
100 if timeout is not None:
101 if _timer() >= stop_at:
102 raise TimeoutExpired(timeout, pid=pid, name=proc_name)
103 _sleep(interval)
104 return _min(interval * 2, 0.04)
106 # See: https://linux.die.net/man/2/waitpid
107 while True:
108 try:
109 retpid, status = os.waitpid(pid, flags)
110 except InterruptedError:
111 interval = sleep(interval)
112 except ChildProcessError:
113 # This has two meanings:
114 # - PID is not a child of os.getpid() in which case
115 # we keep polling until it's gone
116 # - PID never existed in the first place
117 # In both cases we'll eventually return None as we
118 # can't determine its exit status code.
119 while _pid_exists(pid):
120 interval = sleep(interval)
121 return None
122 else:
123 if retpid == 0:
124 # WNOHANG flag was used and PID is still running.
125 interval = sleep(interval)
126 continue
128 if os.WIFEXITED(status):
129 # Process terminated normally by calling exit(3) or _exit(2),
130 # or by returning from main(). The return value is the
131 # positive integer passed to *exit().
132 return os.WEXITSTATUS(status)
133 elif os.WIFSIGNALED(status):
134 # Process exited due to a signal. Return the negative value
135 # of that signal.
136 return negsig_to_enum(-os.WTERMSIG(status))
137 # elif os.WIFSTOPPED(status):
138 # # Process was stopped via SIGSTOP or is being traced, and
139 # # waitpid() was called with WUNTRACED flag. PID is still
140 # # alive. From now on waitpid() will keep returning (0, 0)
141 # # until the process state doesn't change.
142 # # It may make sense to catch/enable this since stopped PIDs
143 # # ignore SIGTERM.
144 # interval = sleep(interval)
145 # continue
146 # elif os.WIFCONTINUED(status):
147 # # Process was resumed via SIGCONT and waitpid() was called
148 # # with WCONTINUED flag.
149 # interval = sleep(interval)
150 # continue
151 else:
152 # Should never happen.
153 msg = f"unknown process exit status {status!r}"
154 raise ValueError(msg)
157def disk_usage(path):
158 """Return disk usage associated with path.
159 Note: UNIX usually reserves 5% disk space which is not accessible
160 by user. In this function "total" and "used" values reflect the
161 total and used disk space whereas "free" and "percent" represent
162 the "free" and "used percent" user disk space.
163 """
164 st = os.statvfs(path)
165 # Total space which is only available to root (unless changed
166 # at system level).
167 total = st.f_blocks * st.f_frsize
168 # Remaining free space usable by root.
169 avail_to_root = st.f_bfree * st.f_frsize
170 # Remaining free space usable by user.
171 avail_to_user = st.f_bavail * st.f_frsize
172 # Total space being used in general.
173 used = total - avail_to_root
174 if MACOS:
175 # see: https://github.com/giampaolo/psutil/pull/2152
176 used = _psutil_osx.disk_usage_used(path, used)
177 # Total space which is available to user (same as 'total' but
178 # for the user).
179 total_user = used + avail_to_user
180 # User usage percent compared to the total amount of space
181 # the user can use. This number would be higher if compared
182 # to root's because the user has less space (usually -5%).
183 usage_percent_user = usage_percent(used, total_user, round_=1)
185 # NB: the percentage is -5% than what shown by df due to
186 # reserved blocks that we are currently not considering:
187 # https://github.com/giampaolo/psutil/issues/829#issuecomment-223750462
188 return sdiskusage(
189 total=total, used=used, free=avail_to_user, percent=usage_percent_user
190 )
193@memoize
194def get_terminal_map():
195 """Get a map of device-id -> path as a dict.
196 Used by Process.terminal().
197 """
198 ret = {}
199 ls = glob.glob('/dev/tty*') + glob.glob('/dev/pts/*')
200 for name in ls:
201 assert name not in ret, name
202 try:
203 ret[os.stat(name).st_rdev] = name
204 except FileNotFoundError:
205 pass
206 return ret