* Pass a fd to program in another mount namespace?
@ 2014-01-21 14:33 Rob van der Hoeven
[not found] ` <1390314790.19789.79.camel-fUTaybRSAecurNyw8EiOWGKXln2oN1SQ@public.gmane.org>
0 siblings, 1 reply; 3+ messages in thread
From: Rob van der Hoeven @ 2014-01-21 14:33 UTC (permalink / raw)
To: containers-cunTk1MwBs9QetFLy7KEm3xJsTq8ys+cHZ5vskTnxNA
Hi,
I was wondering if it is possible to send a file descriptor to a program
running in another mount namespace. Sendmsg/recvmsg can pass fd's in the
ancillary data and this works great until my program switches to another
mount namespace using:
unshare(CLONE_NEWNS)
pivot_root(".", "./us_rootfs")
If there is a way to pass descriptors across mount namespaces then it
would greatly benefit my program so I hope this is possible.
Best regards,
Rob van der Hoeven.
http://freedomboxblog.nl
^ permalink raw reply [flat|nested] 3+ messages in thread[parent not found: <1390314790.19789.79.camel-fUTaybRSAecurNyw8EiOWGKXln2oN1SQ@public.gmane.org>]
* Re: Pass a fd to program in another mount namespace? [not found] ` <1390314790.19789.79.camel-fUTaybRSAecurNyw8EiOWGKXln2oN1SQ@public.gmane.org> @ 2014-01-21 23:07 ` Serge Hallyn 2014-01-22 13:40 ` Rob van der Hoeven 0 siblings, 1 reply; 3+ messages in thread From: Serge Hallyn @ 2014-01-21 23:07 UTC (permalink / raw) To: Rob van der Hoeven; +Cc: containers-cunTk1MwBs9QetFLy7KEm3xJsTq8ys+cHZ5vskTnxNA Quoting Rob van der Hoeven (robvanderhoeven-nv30jWqA7Mk@public.gmane.org): > Hi, > > I was wondering if it is possible to send a file descriptor to a program > running in another mount namespace. Sendmsg/recvmsg can pass fd's in the > ancillary data and this works great until my program switches to another > mount namespace using: > > unshare(CLONE_NEWNS) > pivot_root(".", "./us_rootfs") > > If there is a way to pass descriptors across mount namespaces then it > would greatly benefit my program so I hope this is possible. Yes, it is possible. Your email makes it sound like you've tried and it didn't work for you, in which case a short test case showing what fails might be useful here. -serge ^ permalink raw reply [flat|nested] 3+ messages in thread
* Re: Pass a fd to program in another mount namespace? 2014-01-21 23:07 ` Serge Hallyn @ 2014-01-22 13:40 ` Rob van der Hoeven 0 siblings, 0 replies; 3+ messages in thread From: Rob van der Hoeven @ 2014-01-22 13:40 UTC (permalink / raw) To: Serge Hallyn; +Cc: containers-cunTk1MwBs9QetFLy7KEm3xJsTq8ys+cHZ5vskTnxNA On Tue, 2014-01-21 at 17:07 -0600, Serge Hallyn wrote: > Quoting Rob van der Hoeven (robvanderhoeven-nv30jWqA7Mk@public.gmane.org): > > Hi, > > > > I was wondering if it is possible to send a file descriptor to a program > > running in another mount namespace. Sendmsg/recvmsg can pass fd's in the > > ancillary data and this works great until my program switches to another > > mount namespace using: > > > > unshare(CLONE_NEWNS) > > pivot_root(".", "./us_rootfs") > > > > If there is a way to pass descriptors across mount namespaces then it > > would greatly benefit my program so I hope this is possible. > > Yes, it is possible. Your email makes it sound like you've tried > and it didn't work for you, in which case a short test case showing > what fails might be useful here. > > -serge Hi Serge, Problem solved. It turned out that I had not properly initialized the ancillary header. Because the problem only showed itself after switching to another mount namespace I wrongly assumed that this had something to do with the error. Very happy that this works now. Your answer made me investigate this further, thanks! Rob van der Hoeven. http://freedomboxblog.nl ^ permalink raw reply [flat|nested] 3+ messages in thread
end of thread, other threads:[~2014-01-22 13:40 UTC | newest]
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2014-01-21 14:33 Pass a fd to program in another mount namespace? Rob van der Hoeven
[not found] ` <1390314790.19789.79.camel-fUTaybRSAecurNyw8EiOWGKXln2oN1SQ@public.gmane.org>
2014-01-21 23:07 ` Serge Hallyn
2014-01-22 13:40 ` Rob van der Hoeven
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