Messages in this thread | | | Subject | Re: per-process namespace? | From | Ram Pai <> | Date | 29 Jun 2004 15:25:00 -0700 |
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On Tue, 2004-06-29 at 14:10, Mike Waychison wrote: > -----BEGIN PGP SIGNED MESSAGE----- > Hash: SHA1 > > Ram Pai wrote: > > Is there a way for an application to > > 1. fork its own namespace and modify it, and > > 2. still be able to see changes to the system namespace? > > > > Al Viro's Per-process namespace implementation provides the first > > feature. But is there any work done to do the second part? Is it worth > > doing? > > > > RP > > In what sense? > > The current model has no definition for a 'system namespace'.
by 'system namespace' I mean the very first initial hand-crafted namespace.
> > Accessing /proc/<pid>/mounts where <pid> is running in a different > namespace appears to work.
Are you sure? I dont see it to be the case. I just verified it on 2.6.7 /proc/<pid>/mounts is a file. However /proc/pid/root is a symbolic link to the root directory of the process. So the process with a cloned namespace wont be able to access it through its namespace.
> As well, you can always fchdir back into > another namespace temporarily. As long as you don't reference any > file/directories using absolute paths (including following symlinks), > then you can already navigate the entire namespace.
If this feature is available then great!
> > This falls apart though when there are no longer any processes keeping > that namespace alive. When this happens, the vfsmount's are unstitched > and you end up 'stuck' on a given mount :(.
> Another caveat is that the current system disallows you from doing any > mount/umount's in another namespace (bogus security?) > . > > - -- > Mike Waychison > Sun Microsystems, Inc. > 1 (650) 352-5299 voice > 1 (416) 202-8336 voice > http://www.sun.com > > ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ > NOTICE: The opinions expressed in this email are held by me, > and may not represent the views of Sun Microsystems, Inc. > ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ > -----BEGIN PGP SIGNATURE----- > Version: GnuPG v1.2.4 (GNU/Linux) > > iD8DBQFA4dq9dQs4kOxk3/MRApkaAKCPe0Nw9QBZH425SZeOIvIzSzksUACfQk5D > xLgBDN/dsmVMkAAD73mugiY= > =8OEy > -----END PGP SIGNATURE----- >
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