This commit was manufactured by cvs2svn to create branch 'vserver'.

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

diff --git a/kernel/utsname.c b/kernel/utsname.c
new file mode 100644 (file)
index 0000000..2c1c699
--- /dev/null
+++ b/kernel/utsname.c
@@ -0,0 +1,98 @@
+/*
+ *  Copyright (C) 2004 IBM Corporation
+ *
+ *  Author: Serge Hallyn <serue@us.ibm.com>
+ *
+ *  This program is free software; you can redistribute it and/or
+ *  modify it under the terms of the GNU General Public License as
+ *  published by the Free Software Foundation, version 2 of the
+ *  License.
+ */
+
+#include <linux/module.h>
+#include <linux/uts.h>
+#include <linux/utsname.h>
+#include <linux/version.h>
+#include <linux/vserver/global.h>
+
+/*
+ * 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 uts_namespace *old_ns)
+{
+       struct uts_namespace *ns;
+
+       ns = kmalloc(sizeof(struct uts_namespace), GFP_KERNEL);
+       if (ns) {
+               memcpy(&ns->name, &old_ns->name, sizeof(ns->name));
+               kref_init(&ns->kref);
+               atomic_inc(&vs_global_uts_ns);
+       }
+       return ns;
+}
+
+/*
+ * unshare the current process' utsname namespace.
+ * called only in sys_unshare()
+ */
+int unshare_utsname(unsigned long unshare_flags, struct uts_namespace **new_uts)
+{
+       if (unshare_flags & CLONE_NEWUTS) {
+               if (!capable(CAP_SYS_ADMIN))
+                       return -EPERM;
+
+               *new_uts = clone_uts_ns(current->nsproxy->uts_ns);
+               if (!*new_uts)
+                       return -ENOMEM;
+       }
+
+       return 0;
+}
+
+/*
+ * Copy task tsk's utsname namespace, or clone it if flags
+ * specifies CLONE_NEWUTS.  In latter case, changes to the
+ * 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 *old_ns = tsk->nsproxy->uts_ns;
+       struct uts_namespace *new_ns;
+       int err = 0;
+
+       if (!old_ns)
+               return 0;
+
+       get_uts_ns(old_ns);
+
+       if (!(flags & CLONE_NEWUTS))
+               return 0;
+
+       if (!capable(CAP_SYS_ADMIN)) {
+               err = -EPERM;
+               goto out;
+       }
+
+       new_ns = clone_uts_ns(old_ns);
+       if (!new_ns) {
+               err = -ENOMEM;
+               goto out;
+       }
+       tsk->nsproxy->uts_ns = new_ns;
+
+out:
+       put_uts_ns(old_ns);
+       return err;
+}
+
+void free_uts_ns(struct kref *kref)
+{
+       struct uts_namespace *ns;
+
+       ns = container_of(kref, struct uts_namespace, kref);
+       atomic_dec(&vs_global_uts_ns);
+       kfree(ns);
+}