From 98f842e675f96ffac96e6c50315790912b2812be Mon Sep 17 00:00:00 2001 From: "Eric W. Biederman" Date: Wed, 15 Jun 2011 10:21:48 -0700 Subject: 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 --- include/linux/proc_fs.h | 7 ++++++- 1 file changed, 6 insertions(+), 1 deletion(-) (limited to 'include/linux/proc_fs.h') diff --git a/include/linux/proc_fs.h b/include/linux/proc_fs.h index bf1d000fbba6..2e24018b7cec 100644 --- a/include/linux/proc_fs.h +++ b/include/linux/proc_fs.h @@ -28,7 +28,11 @@ struct mm_struct; */ enum { - PROC_ROOT_INO = 1, + PROC_ROOT_INO = 1, + PROC_IPC_INIT_INO = 0xEFFFFFFFU, + PROC_UTS_INIT_INO = 0xEFFFFFFEU, + PROC_USER_INIT_INO = 0xEFFFFFFDU, + PROC_PID_INIT_INO = 0xEFFFFFFCU, }; /* @@ -263,6 +267,7 @@ struct proc_ns_operations { void *(*get)(struct task_struct *task); void (*put)(void *ns); int (*install)(struct nsproxy *nsproxy, void *ns); + unsigned int (*inum)(void *ns); }; extern const struct proc_ns_operations netns_operations; extern const struct proc_ns_operations utsns_operations; -- cgit v1.2.3