On Sun, 2018-11-18 at 09:21 +0000, M. J. Everitt wrote:
> On 18/11/18 09:18, Michał Górny wrote:
> > On Sun, 2018-11-18 at 09:04 +0000, M. J. Everitt wrote:
> > > On 18/11/18 08:53, Michał Górny wrote:
> > > > Signed-off-by: Michał Górny <mgo...@gentoo.org>
> > > > ---
> > > > bin/pid-ns-init | 25 +++++++++++++++++++++++++
> > > > lib/portage/process.py | 11 ++++++-----
> > > > 2 files changed, 31 insertions(+), 5 deletions(-)
> > > > create mode 100644 bin/pid-ns-init
> > > >
> > > > diff --git a/bin/pid-ns-init b/bin/pid-ns-init
> > > > new file mode 100644
> > > > index 000000000..90660571a
> > > > --- /dev/null
> > > > +++ b/bin/pid-ns-init
> > > > @@ -0,0 +1,25 @@
> > > > +#!/usr/bin/env python
> > > > +# Copyright 2018 Gentoo Authors
> > > > +# Distributed under the terms of the GNU General Public License v2
> > > > +
> > > > +import os
> > > > +import sys
> > > > +
> > > > +
> > > > +def main(argv):
> > > > + if len(argv) < 2:
> > > > + return 'Usage: {} <main-child-pid>'.format(argv[0])
> > > > + main_child_pid = int(argv[1])
> > > > +
> > > > + # wait for child processes
> > > > + while True:
> > > > + pid, status = os.wait()
> > > > + if pid == main_child_pid:
> > > > + return os.WEXITSTATUS(status)
> > > > +
> > > > + # this should never be reached
> > > > + return 127
> > > > +
> > > > +
> > > > +if __name__ == '__main__':
> > > > + sys.exit(main(sys.argv))
> > > > diff --git a/lib/portage/process.py b/lib/portage/process.py
> > > > index dee126c3c..75ec299f0 100644
> > > > --- a/lib/portage/process.py
> > > > +++ b/lib/portage/process.py
> > > > @@ -544,13 +544,14 @@ def _exec(binary, mycommand, opt_name, fd_pipes,
> > > > env, gid, groups, uid, umask,
> > > > else:
> > > > if unshare_pid:
> > > > # pid namespace
> > > > requires us to become init
> > > > - # TODO: do
> > > > init-ty stuff
> > > > - # therefore,
> > > > fork() ASAP
> > > > fork_ret =
> > > > os.fork()
> > > > if fork_ret !=
> > > > 0:
> > > > - pid,
> > > > status = os.waitpid(fork_ret, 0)
> > > > - assert
> > > > pid == fork_ret
> > > > -
> > > > os._exit(status)
> > > > +
> > > > os.execv(portage._python_interpreter, [
> > > > +
> > > > portage._python_interpreter,
> > > > +
> > > > os.path.join(portage._bin_path,
> > > > +
> > > > 'pid-ns-init'),
> > > > +
> > > > '%s' % fork_ret,
> > > > +
> > > > ])
> > > > if unshare_mount:
> > > > # mark the
> > > > whole filesystem as slave to avoid
> > > > # mounts
> > > > escaping the namespace
> > >
> > > Why in python?! Surely a small C app would be significantly more
> > > efficient ..
> > >
> >
> > Surely adding a new build system for C apps would be entirely justified
> > by the necessity of premature optimization of program that spends ~100%
> > of its time in wait().
> >
>
> Forgive my ignorance then .. what purpose does a process have which simply
> wait()s ?! .. no, on second thoughts, don't answer that question, I'm
> unlikely to like the answer anyway ...
> Well, if you find it useless, then I would suggest you save some space by doing: rm /sbin/init -- Best regards, Michał Górny
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