Use subprocess.Popen to correctly configure the signal disposition of the child process, since os.fork leaves the signal disposition in a state which may be inappropriate for various signals including SIGPIPE, SIGQUIT, SIGTERM, and SIGINT. For python implementations other that CPython >= 3, use preexec_fn to manually configure the signal disposition (I have found that this is necessary for CPython 2.7 and all PyPy versions tested, including PyPy3).
Bug: https://bugs.gentoo.org/675828 Signed-off-by: Zac Medico <zmed...@gentoo.org> --- bin/pid-ns-init | 31 ++++++++++++++++++++++++++++--- 1 file changed, 28 insertions(+), 3 deletions(-) diff --git a/bin/pid-ns-init b/bin/pid-ns-init index 182d00a43..86029f983 100644 --- a/bin/pid-ns-init +++ b/bin/pid-ns-init @@ -2,18 +2,37 @@ # Copyright 2018-2019 Gentoo Authors # Distributed under the terms of the GNU General Public License v2 +import errno import functools import os +import platform import signal +import subprocess import sys +if sys.version_info.major < 3 or platform.python_implementation() != 'CPython': + def signal_disposition_preexec(): + for signum in ( + signal.SIGHUP, + signal.SIGINT, + signal.SIGPIPE, + signal.SIGQUIT, + signal.SIGTERM, + ): + signal.signal(signum, signal.SIG_DFL) +else: + # CPython >= 3 subprocess.Popen handles this internally. + signal_disposition_preexec = None + + KILL_SIGNALS = ( signal.SIGINT, signal.SIGTERM, signal.SIGHUP, ) + def forward_kill_signal(main_child_pid, signum, frame): os.kill(main_child_pid, signum) @@ -28,14 +47,15 @@ def main(argv): # (forwarding signals to init and forwarding exit status to the parent # process). main_child_pid = int(argv[1]) + proc = None else: # The current process is init (pid 1) in a child pid namespace. binary = argv[1] args = argv[2:] - main_child_pid = os.fork() - if main_child_pid == 0: - os.execv(binary, args) + proc = subprocess.Popen(args, executable=binary, + preexec_fn=signal_disposition_preexec) + main_child_pid = proc.pid sig_handler = functools.partial(forward_kill_signal, main_child_pid) for signum in KILL_SIGNALS: @@ -50,6 +70,11 @@ def main(argv): continue raise if pid == main_child_pid: + if proc is not None: + # Suppress warning messages like this: + # ResourceWarning: subprocess 1234 is still running + proc.returncode = 0 + if os.WIFEXITED(status): return os.WEXITSTATUS(status) elif os.WIFSIGNALED(status): -- 2.18.1
