Re: [PATCH V3 0/6] namespaces: log namespaces per task

The purpose is to track namespaces in use by logged processes from the perspective of init_*_ns. 1/6 defines a function to generate them and assigns them. Use a serial number per namespace (unique across one boot of one kernel) instead of the inode number (which is claimed to have had the right to change reserved and is not necessarily unique if there is more than one proc fs). It could be argued that the inode numbers have now become a defacto interface and can't change now, but I'm proposing this approach to see if this helps address some of the objections to the earlier patchset. 2/6 adds access functions to get to the serial numbers in a similar way to inode access for namespace proc operations. 3/6 implements, as suggested by Serge Hallyn, making these serial numbers available in /proc/self/ns/{ipc,mnt,net,pid,user,uts}_snum. I chose "snum" instead of "seq" for consistency with inum and there are a number of other uses of "seq" in the namespace code. 4/6 exposes proc's ns entries structure which lists a number of useful operations per namespace type for other subsystems to use. 5/6 provides an example of usage for audit_log_task_info() which is used by syscall audits, among others. audit_log_task() and audit_common_recv_message() would be other potential use cases. Proposed output format: This differs slightly from Aristeu's patch because of the label conflict with "pid=" due to including it in existing records rather than it being a seperate record. The serial numbers are printed in hex. type=SYSCALL msg=audit(1399651071.433:72): arch=c000003e syscall=272 success=yes exit=0 a0=40000000 a1=ffffffffffffffff a2=0 a3=22 items=0 ppid=1 pid=483 auid=4294967295 uid=0 gid=0 euid=0 suid=0 fsuid=0 egid=0 sgid=0 fsgid=0 tty=(none) ses=4294967295 comm="(t-daemon)" exe="/usr/lib/systemd/systemd" netns=97 utsns=2 ipcns=1 pidns=4 userns=3 mntns=5 subj=system_u:system_r:init_t:s0 key=(null)

6/6 tracks the creation and deletion of of namespaces, listing the type of namespace instance, related namespace id if there is one and the newly minted serial number. Proposed output format: type=NS_INIT msg=audit(1400217435.706:94): pid=524 uid=0 auid=4294967295 ses=4294967295 subj=system_u:system_r:mount_t:s0 type=20000 old_snum=0 snum=a1 res=1