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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
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')
-rw-r--r--include/linux/ipc_namespace.h2
-rw-r--r--include/linux/pid_namespace.h1
-rw-r--r--include/linux/proc_fs.h7
-rw-r--r--include/linux/user_namespace.h1
-rw-r--r--include/linux/utsname.h1
5 files changed, 11 insertions, 1 deletions
diff --git a/include/linux/ipc_namespace.h b/include/linux/ipc_namespace.h
index f03af702a39..fe771978e87 100644
--- a/include/linux/ipc_namespace.h
+++ b/include/linux/ipc_namespace.h
@@ -67,6 +67,8 @@ struct ipc_namespace {
/* user_ns which owns the ipc ns */
struct user_namespace *user_ns;
+
+ unsigned int proc_inum;
};
extern struct ipc_namespace init_ipc_ns;
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;
diff --git a/include/linux/proc_fs.h b/include/linux/proc_fs.h
index bf1d000fbba..2e24018b7ce 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;
diff --git a/include/linux/user_namespace.h b/include/linux/user_namespace.h
index 17651f08d67..b9bd2e6c73c 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;
diff --git a/include/linux/utsname.h b/include/linux/utsname.h
index 221f4a0a750..239e27733d6 100644
--- a/include/linux/utsname.h
+++ b/include/linux/utsname.h
@@ -23,6 +23,7 @@ struct uts_namespace {
struct kref kref;
struct new_utsname name;
struct user_namespace *user_ns;
+ unsigned int proc_inum;
};
extern struct uts_namespace init_uts_ns;