On Tue, Jun 02, 2020 at 02:03:09PM -0700, Linus Torvalds wrote: > On Tue, Jun 2, 2020 at 1:42 PM Christian Brauner > <christian.brauner@xxxxxxxxxx> wrote: > > > > This is a resend of the close_range() syscall, as discussed in [1]. There weren't any outstanding > > discussions anymore and this was in mergeable shape. I simply hadn't gotten around to moving this > > into my for-next the last few cycles and then forgot about it. Thanks to Kyle and the Python people, > > and others for consistenly reminding me before every merge window and mea culpa for not moving on > > this sooner. I plan on moving this into for-next after v5.8-rc1 has been released and targeting the > > v5.9 merge window. > > Btw, I did have one reaction that I can't find in the original thread, > which probably means that it got lost. > > If one of the designed uses for this is for dropping file descriptors > just before execve(), it's possible that we'd want to have the option > to say "unshare my fd array" as part of close_range(). > > Yes, yes, you can do > > unshare(CLONE_FILES); > close_range(3,~0u); > > to do it as two operations (and you had that as the example typical > use), but it would actually be better to be able to do > > close_range(3, ~0ul, CLOSE_RANGE_UNSHARE); > > instead. Because otherwise we just waste time copying the file > descriptors first in the unshare, and then closing them after.. Double > the work.. > > And maybe this _did_ get mentioned last time, and I just don't find > it. I also don't see anything like that in the patches, although the > flags argument is there. I spent some good time digging and I couldn't find this mentioned anywhere so maybe it just never got sent to the list? It sounds pretty useful, so yeah let me add a patch for this tomorrow. Christian
