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 ...
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