Messages in this thread | | | Date | Mon, 20 Feb 2006 12:27:03 +0300 | From | Kirill Korotaev <> | Subject | Re: [RFC][PATCH 04/20] pspace: Allow multiple instaces of the process id namespace |
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>>>I also don't understand why you are eager to introduce new sys calls >>>like pkill(path_to_process), but is trying to use waitpid() for pspace >>>die notifications? Maybe it is simply better to introduce container >>>specific syscalls which should be clean and tidy, instead of messing >>>things up with clone()/waitpid() and so on? The more simple code we >>>have, the better it is for all of us. >> >>now that you mention it, maybe we should have a few >>rounds how those 'generic' container syscalls would >>look like? > > > I still like the following: > > clone(): extended with flags for asking a private copy of various > namespaces. For the CLONE_NEWPIDSPACE flag, the pid which > is returned to the parent process is it's handle to the > new pidspace. - clone has limited number of flags. - sooner or later you will need to add flags about what and how you want to close (e.g. pspace with weak or strong isolation and so on)
> sys_execpid(pid, argv, envp): exec a new syscall with the requested > pid, if the pid is available. Else either return an error, > or pick a random pid. Error makes sense to me, but that's > probably debatable. the problem is that in real life environments where executables can be substitutes this is kind of a security issue. Also I really hate the idea of using exec() for changing something. In OpenVZ we successfully do context changes without exec()'s.
> sys_fork_slide(pid): fork and slide into the pidspace belong to pid. > This way we can do things like > > p = sys_fork_slide(2794); > if (p == 0) { > kill(2974); > } else { > waitpid(p, 0, 0); > } > Ok, this last one in particular needs to be improved, but these two > syscalls and the clone flags together give us all we need. Right? Again, you concentrate on PIDspaces forgeting about all the other namespaces.
I would prefer:
- sys_ns_create() creates namespace and makes a task to inherit this namespace. If _needed_, it _can_ fork inside.
- sys_ns_inherit() change active namespace.
But how should we reference namespace? by globabl ID?
Kirill
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