Michael, Here is the proposal for a description of signals handling in pid namespaces. This applies on top of your CLONE_NEWPID patch. Regards, Nadia --- man2/clone.2 | 23 +++++++++++++++++++++++ 1 file changed, 23 insertions(+) Index: man-pages-3.13/man2/clone.2 =================================================================== --- man-pages-3.13.orig/man2/clone.2 2008-11-24 09:34:30.000000000 +0100 +++ man-pages-3.13/man2/clone.2 2008-11-27 09:17:53.000000000 +0100 @@ -226,6 +226,29 @@ configuration option and requires that t .RB (CAP_SYS_ADMIN ). This flag can't be specified in conjunction with .BR CLONE_THREAD . + +.BR "Signals handling:" +just like all the system calls that address a PID, signals can only be sent +to a process whose PID belongs to the same namespace as the caller. + +There are ways signals can be sent across namespaces boundaries such that +the sender does not have a valid pid in the receiver's pid namespace. +In such cases, the sender pid will be seen by the receiver as a 0 value +(this has an impact, for example, on the +.BR siginfo_t +structure contents - NOTE, this is still under development). + +The "init" process of a PID namespace has a particular status, since it +is known both by its children as PID 1 and by its father's PID namespace +as any other PID. Thus, the "init" process of a PID namespace can be sent +any signal by a process that belongs to its ancestor's PID namespace (given +that the sender has the appropriate permission). But the only signals that +can be sent to the "init" process of a PID namespace from its own namespace +are those for which it has explicitly installed signal handlers. +More precisely, signals are sent successfully (i.e +.BR kill (2) +will not fail), but the "init" process will silently ignore unhandled signals. + .TP .BR CLONE_PARENT " (since Linux 2.3.12)" If -- -- To unsubscribe from this list: send the line "unsubscribe linux-man" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
