tracing: Add tracepoints for hotplug

[linux-2.6.git] / kernel / utsname.c

diff --git a/kernel/utsname.c b/kernel/utsname.c
index 1824384ecfa3225f11b1a30b0e9f79dea3c46327..bff131b9510a425452428005afda0acf7c979507 100644 (file)
--- a/kernel/utsname.c
+++ b/kernel/utsname.c
@@ -12,7 +12,41 @@
 #include <linux/module.h>
 #include <linux/uts.h>
 #include <linux/utsname.h>
-#include <linux/version.h>
+#include <linux/err.h>
+#include <linux/slab.h>
+#include <linux/user_namespace.h>
+#include <linux/proc_fs.h>
+
+static struct uts_namespace *create_uts_ns(void)
+{
+       struct uts_namespace *uts_ns;
+
+       uts_ns = kmalloc(sizeof(struct uts_namespace), GFP_KERNEL);
+       if (uts_ns)
+               kref_init(&uts_ns->kref);
+       return uts_ns;
+}
+
+/*
+ * Clone a new ns copying an original utsname, setting refcount to 1
+ * @old_ns: namespace to clone
+ * Return NULL on error (failure to kmalloc), new ns otherwise
+ */
+static struct uts_namespace *clone_uts_ns(struct task_struct *tsk,
+                                         struct uts_namespace *old_ns)
+{
+       struct uts_namespace *ns;
+
+       ns = create_uts_ns();
+       if (!ns)
+               return ERR_PTR(-ENOMEM);
+
+       down_read(&uts_sem);
+       memcpy(&ns->name, &old_ns->name, sizeof(ns->name));
+       ns->user_ns = get_user_ns(task_cred_xxx(tsk, user)->user_ns);
+       up_read(&uts_sem);
+       return ns;
+}
 
 /*
  * Copy task tsk's utsname namespace, or clone it if flags
@@ -20,17 +54,22 @@
  * utsname of this process won't be seen by parent, and vice
  * versa.
  */
-int copy_utsname(int flags, struct task_struct *tsk)
+struct uts_namespace *copy_utsname(unsigned long flags,
+                                  struct task_struct *tsk)
 {
        struct uts_namespace *old_ns = tsk->nsproxy->uts_ns;
-       int err = 0;
-
-       if (!old_ns)
-               return 0;
+       struct uts_namespace *new_ns;
 
+       BUG_ON(!old_ns);
        get_uts_ns(old_ns);
 
-       return err;
+       if (!(flags & CLONE_NEWUTS))
+               return old_ns;
+
+       new_ns = clone_uts_ns(tsk, old_ns);
+
+       put_uts_ns(old_ns);
+       return new_ns;
 }
 
 void free_uts_ns(struct kref *kref)
@@ -38,5 +77,44 @@ void free_uts_ns(struct kref *kref)
        struct uts_namespace *ns;
 
        ns = container_of(kref, struct uts_namespace, kref);
+       put_user_ns(ns->user_ns);
        kfree(ns);
 }
+
+static void *utsns_get(struct task_struct *task)
+{
+       struct uts_namespace *ns = NULL;
+       struct nsproxy *nsproxy;
+
+       rcu_read_lock();
+       nsproxy = task_nsproxy(task);
+       if (nsproxy) {
+               ns = nsproxy->uts_ns;
+               get_uts_ns(ns);
+       }
+       rcu_read_unlock();
+
+       return ns;
+}
+
+static void utsns_put(void *ns)
+{
+       put_uts_ns(ns);
+}
+
+static int utsns_install(struct nsproxy *nsproxy, void *ns)
+{
+       get_uts_ns(ns);
+       put_uts_ns(nsproxy->uts_ns);
+       nsproxy->uts_ns = ns;
+       return 0;
+}
+
+const struct proc_ns_operations utsns_operations = {
+       .name           = "uts",
+       .type           = CLONE_NEWUTS,
+       .get            = utsns_get,
+       .put            = utsns_put,
+       .install        = utsns_install,
+};
+