[PATCH] namespaces: utsname: implement CLONE_NEWUTS flag

Implement a CLONE_NEWUTS flag, and use it at clone and sys_unshare.

[clg@fr.ibm.com: IPC unshare fix]
[bunk@stusta.de: cleanup]
Signed-off-by: Serge Hallyn <serue@us.ibm.com>
Cc: Kirill Korotaev <dev@openvz.org>
Cc: "Eric W. Biederman" <ebiederm@xmission.com>
Cc: Herbert Poetzl <herbert@13thfloor.at>
Cc: Andrey Savochkin <saw@sw.ru>
Signed-off-by: Adrian Bunk <bunk@stusta.de>
Signed-off-by: Cedric Le Goater <clg@fr.ibm.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>

2 files changed, 12 insertions, 0 deletions

diff --git a/include/linux/sched.h b/include/linux/sched.h
index 46d6f5be72f2..a973e7012315 100644
--- a/include/linux/sched.h
+++ b/include/linux/sched.h
@@ -24,6 +24,7 @@
 #define CLONE_UNTRACED          0x00800000      /* set if the tracing process can't force CLONE_PTRACE on this clone */
 #define CLONE_CHILD_SETTID      0x01000000      /* set the TID in the child */
 #define CLONE_STOPPED           0x02000000      /* Start in stopped state */
+#define CLONE_NEWUTS            0x04000000      /* New utsname group? */
 
 /*
  * Scheduling policies
diff --git a/include/linux/utsname.h b/include/linux/utsname.h
index 99e522369f4f..02e4b6972064 100644
--- a/include/linux/utsname.h
+++ b/include/linux/utsname.h
@@ -47,6 +47,8 @@ static inline void get_uts_ns(struct uts_namespace *ns)
 }
 
 #ifdef CONFIG_UTS_NS
+extern int unshare_utsname(unsigned long unshare_flags,
+                                struct uts_namespace **new_uts);
 extern int copy_utsname(int flags, struct task_struct *tsk);
 extern void free_uts_ns(struct kref *kref);
 
@@ -55,6 +57,15 @@ static inline void put_uts_ns(struct uts_namespace *ns)
         kref_put(&ns->kref, free_uts_ns);
 }
 #else
+static inline int unshare_utsname(unsigned long unshare_flags,
+                        struct uts_namespace **new_uts)
+{
+        if (unshare_flags & CLONE_NEWUTS)
+                return -EINVAL;
+
+        return 0;
+}
+
 static inline int copy_utsname(int flags, struct task_struct *tsk)
 {
         return 0;