"RÃmi Denis-Courmont" <remi@xxxxxxxxxx> writes: > Le samedi 7 mai 2011 05:24:56 Eric W. Biederman, vous avez Ãcrit : >> Pieces of this puzzle can also be solved by instead of >> coming up with a general purpose system call coming up >> with targed system calls perhaps socketat that solve >> a subset of the larger problem. Overall that appears >> to be more work for less reward. > > socketat() is still required for multithreaded namespace-aware userspace, I > believe. The network namespace is a per task property so there are no problems with multithreaded network namespace aware userspace applications. The implementation of a userspace socketat will still need to disable signal handling around the network namespace switch to be signal safe. Which means that ultimately a kernel version of socketat may be desirable, for performance reasons but I know of know correctness reasons to need it. For the time being I have simply removed socketat from what I plan to merge because it is not strictly needed, I don't yet have a test case for socketat, and I don't have as much time to work on this as I would like. There is one bug a multi-threaded network namespace aware user space application might run into, and that is /proc/net is a symlink to /proc/self. Which means that if you open /proc/net/foo from a task with a different network namespace than your the task whose tid equals your tgid, the /proc/net will return the wrong file. Still you can avoid even that silliness by opening /proc/<tid>/net. Eric -- To unsubscribe from this list: send the line "unsubscribe linux-arch" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
