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commit: fb406579b1d13c1ba23b28e0bb794c22878a58c0 |
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Author: Zac Medico <zmedico <AT> gentoo <DOT> org> |
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AuthorDate: Sun Jan 13 23:06:35 2019 +0000 |
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Commit: Zac Medico <zmedico <AT> gentoo <DOT> org> |
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CommitDate: Tue Jan 15 05:45:55 2019 +0000 |
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URL: https://gitweb.gentoo.org/proj/portage.git/commit/?id=fb406579 |
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|
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pid-sandbox: execute pid-ns-init as pid 1 (bug 675312) |
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|
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Execute pid-ns-init as the first fork after unshare, as |
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required for it to have pid 1 and become the default reaper |
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of orphaned descendant processes. In _exec, exec a separate |
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pid-ns-init process to behave as a supervisor which will |
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forward signals to init and forward exit status to the parent |
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process. |
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|
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Fixes: a75d5546e3a4 ("Introduce a tiny init replacement for inside pid namespace") |
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Bug: https://bugs.gentoo.org/675312 |
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Reviewed-by: Brian Dolbec <dolsen <AT> gentoo.org> |
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Signed-off-by: Zac Medico <zmedico <AT> gentoo.org> |
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|
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bin/pid-ns-init | 44 ++++++++++++++++++++++++++++++++++++++++---- |
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lib/portage/process.py | 25 +++++++++++++++++++------ |
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2 files changed, 59 insertions(+), 10 deletions(-) |
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|
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diff --git a/bin/pid-ns-init b/bin/pid-ns-init |
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index 843257b70..182d00a43 100644 |
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--- a/bin/pid-ns-init |
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+++ b/bin/pid-ns-init |
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@@ -1,23 +1,59 @@ |
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#!/usr/bin/env python |
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-# Copyright 2018 Gentoo Authors |
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+# Copyright 2018-2019 Gentoo Authors |
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# Distributed under the terms of the GNU General Public License v2 |
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|
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+import functools |
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import os |
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+import signal |
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import sys |
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|
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|
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+KILL_SIGNALS = ( |
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+ signal.SIGINT, |
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+ signal.SIGTERM, |
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+ signal.SIGHUP, |
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+) |
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+ |
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+def forward_kill_signal(main_child_pid, signum, frame): |
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+ os.kill(main_child_pid, signum) |
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+ |
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+ |
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def main(argv): |
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if len(argv) < 2: |
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- return 'Usage: {} <main-child-pid>'.format(argv[0]) |
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- main_child_pid = int(argv[1]) |
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+ return 'Usage: {} <main-child-pid> or <binary> <argv0> [arg]..'.format(argv[0]) |
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+ |
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+ if len(argv) == 2: |
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+ # The child process is init (pid 1) in a child pid namespace, and |
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+ # the current process supervises from within the global pid namespace |
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+ # (forwarding signals to init and forwarding exit status to the parent |
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+ # process). |
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+ main_child_pid = int(argv[1]) |
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+ else: |
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+ # The current process is init (pid 1) in a child pid namespace. |
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+ binary = argv[1] |
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+ args = argv[2:] |
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+ |
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+ main_child_pid = os.fork() |
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+ if main_child_pid == 0: |
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+ os.execv(binary, args) |
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+ |
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+ sig_handler = functools.partial(forward_kill_signal, main_child_pid) |
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+ for signum in KILL_SIGNALS: |
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+ signal.signal(signum, sig_handler) |
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|
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# wait for child processes |
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while True: |
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- pid, status = os.wait() |
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+ try: |
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+ pid, status = os.wait() |
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+ except OSError as e: |
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+ if e.errno == errno.EINTR: |
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+ continue |
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+ raise |
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if pid == main_child_pid: |
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if os.WIFEXITED(status): |
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return os.WEXITSTATUS(status) |
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elif os.WIFSIGNALED(status): |
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+ signal.signal(os.WTERMSIG(status), signal.SIG_DFL) |
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os.kill(os.getpid(), os.WTERMSIG(status)) |
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# go to the unreachable place |
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break |
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|
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diff --git a/lib/portage/process.py b/lib/portage/process.py |
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index 7103b6b31..6af3ac37d 100644 |
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--- a/lib/portage/process.py |
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+++ b/lib/portage/process.py |
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@@ -564,15 +564,28 @@ def _exec(binary, mycommand, opt_name, fd_pipes, |
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noiselevel=-1) |
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else: |
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if unshare_pid: |
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- # pid namespace requires us to become init |
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- fork_ret = os.fork() |
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- if fork_ret != 0: |
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- os.execv(portage._python_interpreter, [ |
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+ main_child_pid = os.fork() |
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+ if main_child_pid == 0: |
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+ # pid namespace requires us to become init |
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+ binary, myargs = portage._python_interpreter, [ |
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portage._python_interpreter, |
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os.path.join(portage._bin_path, |
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'pid-ns-init'), |
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- '%s' % fork_ret, |
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- ]) |
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+ binary] + myargs |
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+ else: |
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+ # Execute a supervisor process which will forward |
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+ # signals to init and forward exit status to the |
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+ # parent process. The supervisor process runs in |
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+ # the global pid namespace, so skip /proc remount |
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+ # and other setup that's intended only for the |
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+ # init process. |
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+ binary, myargs = portage._python_interpreter, [ |
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+ portage._python_interpreter, |
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+ os.path.join(portage._bin_path, |
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+ 'pid-ns-init'), str(main_child_pid)] |
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+ |
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+ os.execve(binary, myargs, env) |
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+ |
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if unshare_mount: |
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# mark the whole filesystem as slave to avoid |
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# mounts escaping the namespace |
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