commit: 0d18c696230bcabe007e35194e4b97a38f3b69f5 Author: Zac Medico <zmedico <AT> gentoo <DOT> org> AuthorDate: Sun Jan 20 04:02:35 2019 +0000 Commit: Zac Medico <zmedico <AT> gentoo <DOT> org> CommitDate: Sun Jan 20 23:31:41 2019 +0000 URL: https://gitweb.gentoo.org/proj/portage.git/commit/?id=0d18c696
pid-ns-init: fix child process signal disposition (bug 675828) 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 <zmedico <AT> gentoo.org> bin/pid-ns-init | 39 +++++++++++++++++++++++++++++++++------ lib/portage/process.py | 1 + 2 files changed, 34 insertions(+), 6 deletions(-) diff --git a/bin/pid-ns-init b/bin/pid-ns-init index 182d00a43..f9b8cc4f3 100644 --- a/bin/pid-ns-init +++ b/bin/pid-ns-init @@ -2,25 +2,44 @@ # 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) def main(argv): if len(argv) < 2: - return 'Usage: {} <main-child-pid> or <binary> <argv0> [arg]..'.format(argv[0]) + return 'Usage: {} <main-child-pid> or <pass_fds> <binary> <argv0> [arg]..'.format(argv[0]) if len(argv) == 2: # The child process is init (pid 1) in a child pid namespace, and @@ -28,14 +47,17 @@ 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:] + pass_fds, binary, args = tuple(int(fd) for fd in argv[1].split(',')), argv[2], argv[3:] - main_child_pid = os.fork() - if main_child_pid == 0: - os.execv(binary, args) + popen_kwargs = {} + if sys.version_info.major > 2: + popen_kwargs['pass_fds'] = pass_fds + proc = subprocess.Popen(args, executable=binary, + preexec_fn=signal_disposition_preexec, **popen_kwargs) + main_child_pid = proc.pid sig_handler = functools.partial(forward_kill_signal, main_child_pid) for signum in KILL_SIGNALS: @@ -50,6 +72,11 @@ 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): diff --git a/lib/portage/process.py b/lib/portage/process.py index 6af3ac37d..dd3d58ddc 100644 --- a/lib/portage/process.py +++ b/lib/portage/process.py @@ -571,6 +571,7 @@ def _exec(binary, mycommand, opt_name, fd_pipes, portage._python_interpreter, os.path.join(portage._bin_path, 'pid-ns-init'), + _unicode_encode(','.join(str(fd) for fd in fd_pipes)), binary] + myargs else: # Execute a supervisor process which will forward
