[PATCH] to nsproxy

Add the pid namespace framework to the nsproxy object.  The copy of the pid
namespace only increases the refcount on the global pid namespace,
init_pid_ns, and unshare is not implemented.

There is no configuration option to activate or deactivate this feature
because this not relevant for the moment.

Signed-off-by: Cedric Le Goater <clg@fr.ibm.com>
Cc: Kirill Korotaev <dev@openvz.org>
Cc: Eric W. Biederman <ebiederm@xmission.com>
Cc: Herbert Poetzl <herbert@13thfloor.at>
Cc: Sukadev Bhattiprolu <sukadev@us.ibm.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>

3 files changed, 22 insertions, 2 deletions

diff --git a/include/linux/init_task.h b/include/linux/init_task.h
index 90c5f9a0773..7272ff9ee77 100644
--- a/include/linux/init_task.h
+++ b/include/linux/init_task.h
@@ -7,6 +7,7 @@
 #include <linux/utsname.h>
 #include <linux/lockdep.h>
 #include <linux/ipc.h>
+#include <linux/pid_namespace.h>
 
 #define INIT_FDTABLE \
 {                                                       \
@@ -73,6 +74,7 @@
 
 extern struct nsproxy init_nsproxy;
 #define INIT_NSPROXY(nsproxy) {                                         \
+        .pid_ns         = &init_pid_ns,                                 \
         .count          = ATOMIC_INIT(1),                               \
         .nslock         = __SPIN_LOCK_UNLOCKED(nsproxy.nslock),         \
         .id             = 0,                                            \
diff --git a/include/linux/nsproxy.h b/include/linux/nsproxy.h
index 27f37c1ec1d..fdfb0e44912 100644
--- a/include/linux/nsproxy.h
+++ b/include/linux/nsproxy.h
@@ -7,6 +7,7 @@
 struct mnt_namespace;
 struct uts_namespace;
 struct ipc_namespace;
+struct pid_namespace;
 
 /*
  * A structure to contain pointers to all per-process
@@ -27,6 +28,7 @@ struct nsproxy {
         struct uts_namespace *uts_ns;
         struct ipc_namespace *ipc_ns;
         struct mnt_namespace *mnt_ns;
+        struct pid_namespace *pid_ns;
 };
 extern struct nsproxy init_nsproxy;
 
diff --git a/include/linux/pid_namespace.h b/include/linux/pid_namespace.h
index 54d79095e29..76e7c6b2cf3 100644
--- a/include/linux/pid_namespace.h
+++ b/include/linux/pid_namespace.h
@@ -5,6 +5,8 @@
 #include <linux/mm.h>
 #include <linux/threads.h>
 #include <linux/pid.h>
+#include <linux/nsproxy.h>
+#include <linux/kref.h>
 
 struct pidmap {
        atomic_t nr_free;
@@ -14,10 +16,24 @@ struct pidmap {
 #define PIDMAP_ENTRIES         ((PID_MAX_LIMIT + 8*PAGE_SIZE - 1)/PAGE_SIZE/8)
 
 struct pid_namespace {
-       struct pidmap pidmap[PIDMAP_ENTRIES];
-       int last_pid;
+        struct kref kref;
+        struct pidmap pidmap[PIDMAP_ENTRIES];
+        int last_pid;
 };
 
 extern struct pid_namespace init_pid_ns;
 
+static inline void get_pid_ns(struct pid_namespace *ns)
+{
+        kref_get(&ns->kref);
+}
+
+extern int copy_pid_ns(int flags, struct task_struct *tsk);
+extern void free_pid_ns(struct kref *kref);
+
+static inline void put_pid_ns(struct pid_namespace *ns)
+{
+        kref_put(&ns->kref, free_pid_ns);
+}
+
 #endif /* _LINUX_PID_NS_H */