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authorEric W. Biederman <ebiederm@xmission.com>2011-06-15 10:21:48 -0700
committerEric W. Biederman <ebiederm@xmission.com>2012-11-20 04:19:49 -0800
commit98f842e675f96ffac96e6c50315790912b2812be (patch)
treeed4dee9a6e54e3443e9f3f1614c8a2fcf9b31e0a /include/linux/pid_namespace.h
parentbf056bfa80596a5d14b26b17276a56a0dcb080e5 (diff)
downloadvexpress-lsk-98f842e675f96ffac96e6c50315790912b2812be.tar.gz
proc: Usable inode numbers for the namespace file descriptors.
Assign a unique proc inode to each namespace, and use that inode number to ensure we only allocate at most one proc inode for every namespace in proc. A single proc inode per namespace allows userspace to test to see if two processes are in the same namespace. This has been a long requested feature and only blocked because a naive implementation would put the id in a global space and would ultimately require having a namespace for the names of namespaces, making migration and certain virtualization tricks impossible. We still don't have per superblock inode numbers for proc, which appears necessary for application unaware checkpoint/restart and migrations (if the application is using namespace file descriptors) but that is now allowd by the design if it becomes important. I have preallocated the ipc and uts initial proc inode numbers so their structures can be statically initialized. Signed-off-by: Eric W. Biederman <ebiederm@xmission.com>
Diffstat (limited to 'include/linux/pid_namespace.h')
-rw-r--r--include/linux/pid_namespace.h1
1 files changed, 1 insertions, 0 deletions
diff --git a/include/linux/pid_namespace.h b/include/linux/pid_namespace.h
index 4c96acdb248..bf285999273 100644
--- a/include/linux/pid_namespace.h
+++ b/include/linux/pid_namespace.h
@@ -37,6 +37,7 @@ struct pid_namespace {
kgid_t pid_gid;
int hide_pid;
int reboot; /* group exit code if this pidns was rebooted */
+ unsigned int proc_inum;
};
extern struct pid_namespace init_pid_ns;