Eric Lee / smarc-fsl-linux-kernel

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kernel/utsname.c 1.96 KB
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4865ecf13   Serge E. Hallyn   [PATCH] namespace... 
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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>
  
  /*
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   * 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;
  }
  
  /*
4865ecf13   Serge E. Hallyn   [PATCH] namespace... 
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   * 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;
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  	struct uts_namespace *new_ns;
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  	int err = 0;
  
  	if (!old_ns)
  		return 0;
  
  	get_uts_ns(old_ns);
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  	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);
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  	return err;
  }
  
  void free_uts_ns(struct kref *kref)
  {
  	struct uts_namespace *ns;
  
  	ns = container_of(kref, struct uts_namespace, kref);
  	kfree(ns);
  }