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author | Eric W. Biederman <ebiederm@xmission.com> | 2011-06-15 10:21:48 -0700 |
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committer | Eric W. Biederman <ebiederm@xmission.com> | 2012-11-20 04:19:49 -0800 |
commit | 98f842e675f96ffac96e6c50315790912b2812be (patch) | |
tree | ed4dee9a6e54e3443e9f3f1614c8a2fcf9b31e0a /include/linux/user_namespace.h | |
parent | bf056bfa80596a5d14b26b17276a56a0dcb080e5 (diff) | |
download | linux-stable-98f842e675f96ffac96e6c50315790912b2812be.tar.gz linux-stable-98f842e675f96ffac96e6c50315790912b2812be.tar.bz2 linux-stable-98f842e675f96ffac96e6c50315790912b2812be.zip |
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/user_namespace.h')
-rw-r--r-- | include/linux/user_namespace.h | 1 |
1 files changed, 1 insertions, 0 deletions
diff --git a/include/linux/user_namespace.h b/include/linux/user_namespace.h index 17651f08d67f..b9bd2e6c73cc 100644 --- a/include/linux/user_namespace.h +++ b/include/linux/user_namespace.h @@ -25,6 +25,7 @@ struct user_namespace { struct user_namespace *parent; kuid_t owner; kgid_t group; + unsigned int proc_inum; }; extern struct user_namespace init_user_ns; |