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On Sun, 2018-11-18 at 09:04 +0000, M. J. Everitt wrote: |
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> On 18/11/18 08:53, Michał Górny wrote: |
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> > Signed-off-by: Michał Górny <mgorny@g.o> |
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> > --- |
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> > bin/pid-ns-init | 25 +++++++++++++++++++++++++ |
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> > lib/portage/process.py | 11 ++++++----- |
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> > 2 files changed, 31 insertions(+), 5 deletions(-) |
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> > create mode 100644 bin/pid-ns-init |
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> > |
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> > diff --git a/bin/pid-ns-init b/bin/pid-ns-init |
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> > new file mode 100644 |
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> > index 000000000..90660571a |
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> > --- /dev/null |
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> > +++ b/bin/pid-ns-init |
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> > @@ -0,0 +1,25 @@ |
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> > +#!/usr/bin/env python |
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> > +# Copyright 2018 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 os |
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> > +import sys |
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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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> > + |
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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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> > + if pid == main_child_pid: |
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> > + return os.WEXITSTATUS(status) |
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> > + |
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> > + # this should never be reached |
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> > + return 127 |
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> > + |
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> > + |
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> > +if __name__ == '__main__': |
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> > + sys.exit(main(sys.argv)) |
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> > diff --git a/lib/portage/process.py b/lib/portage/process.py |
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> > index dee126c3c..75ec299f0 100644 |
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> > --- a/lib/portage/process.py |
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> > +++ b/lib/portage/process.py |
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> > @@ -544,13 +544,14 @@ def _exec(binary, mycommand, opt_name, fd_pipes, env, gid, groups, uid, umask, |
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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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> > - # TODO: do init-ty stuff |
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> > - # therefore, fork() ASAP |
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> > fork_ret = os.fork() |
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> > if fork_ret != 0: |
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> > - pid, status = os.waitpid(fork_ret, 0) |
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> > - assert pid == fork_ret |
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> > - os._exit(status) |
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> > + os.execv(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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> > 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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> |
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> Why in python?! Surely a small C app would be significantly more efficient .. |
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> |
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|
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Surely adding a new build system for C apps would be entirely justified |
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by the necessity of premature optimization of program that spends ~100% |
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of its time in wait(). |
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|
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-- |
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Best regards, |
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Michał Górny |
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