This patch adds 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 <[email protected]>
Cc: Kirill Korotaev <[email protected]>
Cc: Eric W. Biederman <[email protected]>
Cc: Herbert Poetzl <[email protected]>
Cc: Sukadev Bhattiprolu <[email protected]>
Cc: Andrew Morton <[email protected]>
---
include/linux/init_task.h | 2 ++
include/linux/nsproxy.h | 2 ++
include/linux/pid_namespace.h | 20 ++++++++++++++++++--
kernel/nsproxy.c | 26 +++++++++++++++++++-------
kernel/pid.c | 23 +++++++++++++++++++++++
5 files changed, 64 insertions(+), 9 deletions(-)
Index: 2.6.19-rc2-mm1/include/linux/init_task.h
===================================================================
--- 2.6.19-rc2-mm1.orig/include/linux/init_task.h
+++ 2.6.19-rc2-mm1/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 \
{ \
@@ -70,6 +71,7 @@
extern struct nsproxy init_nsproxy;
#define INIT_NSPROXY(nsproxy) { \
+ .pid_ns = &init_pid_ns, \
.count = ATOMIC_INIT(1), \
.nslock = SPIN_LOCK_UNLOCKED, \
.id = 0, \
Index: 2.6.19-rc2-mm1/include/linux/nsproxy.h
===================================================================
--- 2.6.19-rc2-mm1.orig/include/linux/nsproxy.h
+++ 2.6.19-rc2-mm1/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;
Index: 2.6.19-rc2-mm1/include/linux/pid_namespace.h
===================================================================
--- 2.6.19-rc2-mm1.orig/include/linux/pid_namespace.h
+++ 2.6.19-rc2-mm1/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 */
Index: 2.6.19-rc2-mm1/kernel/nsproxy.c
===================================================================
--- 2.6.19-rc2-mm1.orig/kernel/nsproxy.c
+++ 2.6.19-rc2-mm1/kernel/nsproxy.c
@@ -19,6 +19,7 @@
#include <linux/init_task.h>
#include <linux/mnt_namespace.h>
#include <linux/utsname.h>
+#include <linux/pid_namespace.h>
struct nsproxy init_nsproxy = INIT_NSPROXY(init_nsproxy);
@@ -69,6 +70,8 @@ struct nsproxy *dup_namespaces(struct ns
get_uts_ns(ns->uts_ns);
if (ns->ipc_ns)
get_ipc_ns(ns->ipc_ns);
+ if (ns->pid_ns)
+ get_pid_ns(ns->pid_ns);
}
return ns;
@@ -112,10 +115,17 @@ int copy_namespaces(int flags, struct ta
if (err)
goto out_ipc;
+ err = copy_pid_ns(flags, tsk);
+ if (err)
+ goto out_pid;
+
out:
put_nsproxy(old_ns);
return err;
+out_pid:
+ if (new_ns->ipc_ns)
+ put_ipc_ns(new_ns->ipc_ns);
out_ipc:
if (new_ns->uts_ns)
put_uts_ns(new_ns->uts_ns);
@@ -130,11 +140,13 @@ out_ns:
void free_nsproxy(struct nsproxy *ns)
{
- if (ns->mnt_ns)
- put_mnt_ns(ns->mnt_ns);
- if (ns->uts_ns)
- put_uts_ns(ns->uts_ns);
- if (ns->ipc_ns)
- put_ipc_ns(ns->ipc_ns);
- kfree(ns);
+ if (ns->mnt_ns)
+ put_mnt_ns(ns->mnt_ns);
+ if (ns->uts_ns)
+ put_uts_ns(ns->uts_ns);
+ if (ns->ipc_ns)
+ put_ipc_ns(ns->ipc_ns);
+ if (ns->pid_ns)
+ put_pid_ns(ns->pid_ns);
+ kfree(ns);
}
Index: 2.6.19-rc2-mm1/kernel/pid.c
===================================================================
--- 2.6.19-rc2-mm1.orig/kernel/pid.c
+++ 2.6.19-rc2-mm1/kernel/pid.c
@@ -59,6 +59,9 @@ static inline int mk_pid(struct pid_name
* the scheme scales to up to 4 million PIDs, runtime.
*/
struct pid_namespace init_pid_ns = {
+ .kref = {
+ .refcount = ATOMIC_INIT(2),
+ },
.pidmap = {
[ 0 ... PIDMAP_ENTRIES-1] = { ATOMIC_INIT(BITS_PER_PAGE), NULL }
},
@@ -357,6 +360,26 @@ struct pid *find_ge_pid(int nr)
}
EXPORT_SYMBOL_GPL(find_get_pid);
+int copy_pid_ns(int flags, struct task_struct *tsk)
+{
+ struct pid_namespace *old_ns = tsk->nsproxy->pid_ns;
+ int err = 0;
+
+ if (!old_ns)
+ return 0;
+
+ get_pid_ns(old_ns);
+ return err;
+}
+
+void free_pid_ns(struct kref *kref)
+{
+ struct pid_namespace *ns;
+
+ ns = container_of(kref, struct pid_namespace, kref);
+ kfree(ns);
+}
+
/*
* The pid hash table is scaled according to the amount of memory in the
* machine. From a minimum of 16 slots up to 4096 slots at one gigabyte or
--