1 files changed, 95 insertions, 0 deletions
diff --git a/kernel/utsname.c b/kernel/utsname.c
new file mode 100644
index 0000000000000..c859164a69931
--- /dev/null
+++ b/kernel/utsname.c
@@ -0,0 +1,95 @@
+/*
+ *  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>
+
+/*
+ * 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);
+	}
+	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);
+	kfree(ns);
+}