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- /*
- * 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);
- }
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