/*
   *  linux/kernel/sys.c
   *
   *  Copyright (C) 1991, 1992  Linus Torvalds
   */

  #include <linux/module.h>
  #include <linux/mm.h>
  #include <linux/utsname.h>
  #include <linux/mman.h>
  #include <linux/smp_lock.h>
  #include <linux/notifier.h>
  #include <linux/reboot.h>
  #include <linux/prctl.h>

  #include <linux/highuid.h>
  #include <linux/fs.h>

  #include <linux/kernel.h>
  #include <linux/kexec.h>

  #include <linux/workqueue.h>

  #include <linux/capability.h>

  #include <linux/device.h>
  #include <linux/key.h>
  #include <linux/times.h>
  #include <linux/posix-timers.h>
  #include <linux/security.h>
  #include <linux/dcookies.h>
  #include <linux/suspend.h>
  #include <linux/tty.h>

  #include <linux/signal.h>

  #include <linux/cn_proc.h>

  #include <linux/getcpu.h>

  
  #include <linux/compat.h>
  #include <linux/syscalls.h>

  #include <linux/kprobes.h>

  
  #include <asm/uaccess.h>
  #include <asm/io.h>
  #include <asm/unistd.h>
  
  #ifndef SET_UNALIGN_CTL
  # define SET_UNALIGN_CTL(a,b)	(-EINVAL)
  #endif
  #ifndef GET_UNALIGN_CTL
  # define GET_UNALIGN_CTL(a,b)	(-EINVAL)
  #endif
  #ifndef SET_FPEMU_CTL
  # define SET_FPEMU_CTL(a,b)	(-EINVAL)
  #endif
  #ifndef GET_FPEMU_CTL
  # define GET_FPEMU_CTL(a,b)	(-EINVAL)
  #endif
  #ifndef SET_FPEXC_CTL
  # define SET_FPEXC_CTL(a,b)	(-EINVAL)
  #endif
  #ifndef GET_FPEXC_CTL
  # define GET_FPEXC_CTL(a,b)	(-EINVAL)
  #endif

  #ifndef GET_ENDIAN
  # define GET_ENDIAN(a,b)	(-EINVAL)
  #endif
  #ifndef SET_ENDIAN
  # define SET_ENDIAN(a,b)	(-EINVAL)
  #endif

  
  /*
   * this is where the system-wide overflow UID and GID are defined, for
   * architectures that now have 32-bit UID/GID but didn't in the past
   */
  
  int overflowuid = DEFAULT_OVERFLOWUID;
  int overflowgid = DEFAULT_OVERFLOWGID;
  
  #ifdef CONFIG_UID16
  EXPORT_SYMBOL(overflowuid);
  EXPORT_SYMBOL(overflowgid);
  #endif
  
  /*
   * the same as above, but for filesystems which can only store a 16-bit
   * UID and GID. as such, this is needed on all architectures
   */
  
  int fs_overflowuid = DEFAULT_FS_OVERFLOWUID;
  int fs_overflowgid = DEFAULT_FS_OVERFLOWUID;
  
  EXPORT_SYMBOL(fs_overflowuid);
  EXPORT_SYMBOL(fs_overflowgid);
  
  /*
   * this indicates whether you can reboot with ctrl-alt-del: the default is yes
   */
  
  int C_A_D = 1;

  struct pid *cad_pid;
  EXPORT_SYMBOL(cad_pid);

  
  /*
   *	Notifier list for kernel code which wants to be called
   *	at shutdown. This is used to stop any idling DMA operations
   *	and the like. 
   */

  static BLOCKING_NOTIFIER_HEAD(reboot_notifier_list);
  
  /*
   *	Notifier chain core routines.  The exported routines below
   *	are layered on top of these, with appropriate locking added.
   */
  
  static int notifier_chain_register(struct notifier_block **nl,
  		struct notifier_block *n)
  {
  	while ((*nl) != NULL) {
  		if (n->priority > (*nl)->priority)
  			break;
  		nl = &((*nl)->next);
  	}
  	n->next = *nl;
  	rcu_assign_pointer(*nl, n);
  	return 0;
  }
  
  static int notifier_chain_unregister(struct notifier_block **nl,
  		struct notifier_block *n)
  {
  	while ((*nl) != NULL) {
  		if ((*nl) == n) {
  			rcu_assign_pointer(*nl, n->next);
  			return 0;
  		}
  		nl = &((*nl)->next);
  	}
  	return -ENOENT;
  }
  
  static int __kprobes notifier_call_chain(struct notifier_block **nl,
  		unsigned long val, void *v)
  {
  	int ret = NOTIFY_DONE;

  	struct notifier_block *nb, *next_nb;

  
  	nb = rcu_dereference(*nl);
  	while (nb) {

  		next_nb = rcu_dereference(nb->next);

  		ret = nb->notifier_call(nb, val, v);
  		if ((ret & NOTIFY_STOP_MASK) == NOTIFY_STOP_MASK)
  			break;

  		nb = next_nb;

  	}
  	return ret;
  }
  
  /*
   *	Atomic notifier chain routines.  Registration and unregistration

   *	use a spinlock, and call_chain is synchronized by RCU (no locks).

   */

  
  /**

   *	atomic_notifier_chain_register - Add notifier to an atomic notifier chain
   *	@nh: Pointer to head of the atomic notifier chain

   *	@n: New entry in notifier chain
   *

   *	Adds a notifier to an atomic notifier chain.

   *
   *	Currently always returns zero.
   */

  
  int atomic_notifier_chain_register(struct atomic_notifier_head *nh,
  		struct notifier_block *n)
  {
  	unsigned long flags;
  	int ret;
  
  	spin_lock_irqsave(&nh->lock, flags);
  	ret = notifier_chain_register(&nh->head, n);
  	spin_unlock_irqrestore(&nh->lock, flags);
  	return ret;
  }
  
  EXPORT_SYMBOL_GPL(atomic_notifier_chain_register);
  
  /**
   *	atomic_notifier_chain_unregister - Remove notifier from an atomic notifier chain
   *	@nh: Pointer to head of the atomic notifier chain
   *	@n: Entry to remove from notifier chain
   *
   *	Removes a notifier from an atomic notifier chain.
   *
   *	Returns zero on success or %-ENOENT on failure.
   */
  int atomic_notifier_chain_unregister(struct atomic_notifier_head *nh,
  		struct notifier_block *n)
  {
  	unsigned long flags;
  	int ret;
  
  	spin_lock_irqsave(&nh->lock, flags);
  	ret = notifier_chain_unregister(&nh->head, n);
  	spin_unlock_irqrestore(&nh->lock, flags);
  	synchronize_rcu();
  	return ret;
  }
  
  EXPORT_SYMBOL_GPL(atomic_notifier_chain_unregister);
  
  /**
   *	atomic_notifier_call_chain - Call functions in an atomic notifier chain
   *	@nh: Pointer to head of the atomic notifier chain
   *	@val: Value passed unmodified to notifier function
   *	@v: Pointer passed unmodified to notifier function
   *
   *	Calls each function in a notifier chain in turn.  The functions
   *	run in an atomic context, so they must not block.
   *	This routine uses RCU to synchronize with changes to the chain.
   *
   *	If the return value of the notifier can be and'ed
   *	with %NOTIFY_STOP_MASK then atomic_notifier_call_chain
   *	will return immediately, with the return value of
   *	the notifier function which halted execution.
   *	Otherwise the return value is the return value
   *	of the last notifier function called.
   */

  int __kprobes atomic_notifier_call_chain(struct atomic_notifier_head *nh,

  		unsigned long val, void *v)

  {

  	int ret;
  
  	rcu_read_lock();
  	ret = notifier_call_chain(&nh->head, val, v);
  	rcu_read_unlock();
  	return ret;

  }

  EXPORT_SYMBOL_GPL(atomic_notifier_call_chain);
  
  /*
   *	Blocking notifier chain routines.  All access to the chain is
   *	synchronized by an rwsem.
   */

  
  /**

   *	blocking_notifier_chain_register - Add notifier to a blocking notifier chain
   *	@nh: Pointer to head of the blocking notifier chain

   *	@n: New entry in notifier chain
   *

   *	Adds a notifier to a blocking notifier chain.
   *	Must be called in process context.

   *

   *	Currently always returns zero.

   */
   

  int blocking_notifier_chain_register(struct blocking_notifier_head *nh,
  		struct notifier_block *n)

  {

  	int ret;
  
  	/*
  	 * This code gets used during boot-up, when task switching is
  	 * not yet working and interrupts must remain disabled.  At
  	 * such times we must not call down_write().
  	 */
  	if (unlikely(system_state == SYSTEM_BOOTING))
  		return notifier_chain_register(&nh->head, n);
  
  	down_write(&nh->rwsem);
  	ret = notifier_chain_register(&nh->head, n);
  	up_write(&nh->rwsem);
  	return ret;

  }

  EXPORT_SYMBOL_GPL(blocking_notifier_chain_register);

  
  /**

   *	blocking_notifier_chain_unregister - Remove notifier from a blocking notifier chain
   *	@nh: Pointer to head of the blocking notifier chain
   *	@n: Entry to remove from notifier chain
   *
   *	Removes a notifier from a blocking notifier chain.
   *	Must be called from process context.
   *
   *	Returns zero on success or %-ENOENT on failure.
   */
  int blocking_notifier_chain_unregister(struct blocking_notifier_head *nh,
  		struct notifier_block *n)
  {
  	int ret;
  
  	/*
  	 * This code gets used during boot-up, when task switching is
  	 * not yet working and interrupts must remain disabled.  At
  	 * such times we must not call down_write().
  	 */
  	if (unlikely(system_state == SYSTEM_BOOTING))
  		return notifier_chain_unregister(&nh->head, n);
  
  	down_write(&nh->rwsem);
  	ret = notifier_chain_unregister(&nh->head, n);
  	up_write(&nh->rwsem);
  	return ret;
  }
  
  EXPORT_SYMBOL_GPL(blocking_notifier_chain_unregister);
  
  /**
   *	blocking_notifier_call_chain - Call functions in a blocking notifier chain
   *	@nh: Pointer to head of the blocking notifier chain

   *	@val: Value passed unmodified to notifier function
   *	@v: Pointer passed unmodified to notifier function
   *

   *	Calls each function in a notifier chain in turn.  The functions
   *	run in a process context, so they are allowed to block.

   *

   *	If the return value of the notifier can be and'ed
   *	with %NOTIFY_STOP_MASK then blocking_notifier_call_chain

   *	will return immediately, with the return value of
   *	the notifier function which halted execution.

   *	Otherwise the return value is the return value

   *	of the last notifier function called.
   */
   

  int blocking_notifier_call_chain(struct blocking_notifier_head *nh,
  		unsigned long val, void *v)

  {

  	int ret;
  
  	down_read(&nh->rwsem);
  	ret = notifier_call_chain(&nh->head, val, v);
  	up_read(&nh->rwsem);

  	return ret;
  }

  EXPORT_SYMBOL_GPL(blocking_notifier_call_chain);
  
  /*
   *	Raw notifier chain routines.  There is no protection;
   *	the caller must provide it.  Use at your own risk!
   */
  
  /**
   *	raw_notifier_chain_register - Add notifier to a raw notifier chain
   *	@nh: Pointer to head of the raw notifier chain
   *	@n: New entry in notifier chain
   *
   *	Adds a notifier to a raw notifier chain.
   *	All locking must be provided by the caller.
   *
   *	Currently always returns zero.
   */
  
  int raw_notifier_chain_register(struct raw_notifier_head *nh,
  		struct notifier_block *n)
  {
  	return notifier_chain_register(&nh->head, n);
  }
  
  EXPORT_SYMBOL_GPL(raw_notifier_chain_register);
  
  /**
   *	raw_notifier_chain_unregister - Remove notifier from a raw notifier chain
   *	@nh: Pointer to head of the raw notifier chain
   *	@n: Entry to remove from notifier chain
   *
   *	Removes a notifier from a raw notifier chain.
   *	All locking must be provided by the caller.
   *
   *	Returns zero on success or %-ENOENT on failure.
   */
  int raw_notifier_chain_unregister(struct raw_notifier_head *nh,
  		struct notifier_block *n)
  {
  	return notifier_chain_unregister(&nh->head, n);
  }
  
  EXPORT_SYMBOL_GPL(raw_notifier_chain_unregister);
  
  /**
   *	raw_notifier_call_chain - Call functions in a raw notifier chain
   *	@nh: Pointer to head of the raw notifier chain
   *	@val: Value passed unmodified to notifier function
   *	@v: Pointer passed unmodified to notifier function
   *
   *	Calls each function in a notifier chain in turn.  The functions
   *	run in an undefined context.
   *	All locking must be provided by the caller.
   *
   *	If the return value of the notifier can be and'ed
   *	with %NOTIFY_STOP_MASK then raw_notifier_call_chain
   *	will return immediately, with the return value of
   *	the notifier function which halted execution.
   *	Otherwise the return value is the return value
   *	of the last notifier function called.
   */
  
  int raw_notifier_call_chain(struct raw_notifier_head *nh,
  		unsigned long val, void *v)
  {
  	return notifier_call_chain(&nh->head, val, v);
  }
  
  EXPORT_SYMBOL_GPL(raw_notifier_call_chain);

  /*
   *	SRCU notifier chain routines.    Registration and unregistration
   *	use a mutex, and call_chain is synchronized by SRCU (no locks).
   */
  
  /**
   *	srcu_notifier_chain_register - Add notifier to an SRCU notifier chain
   *	@nh: Pointer to head of the SRCU notifier chain
   *	@n: New entry in notifier chain
   *
   *	Adds a notifier to an SRCU notifier chain.
   *	Must be called in process context.
   *
   *	Currently always returns zero.
   */
  
  int srcu_notifier_chain_register(struct srcu_notifier_head *nh,
  		struct notifier_block *n)
  {
  	int ret;
  
  	/*
  	 * This code gets used during boot-up, when task switching is
  	 * not yet working and interrupts must remain disabled.  At
  	 * such times we must not call mutex_lock().
  	 */
  	if (unlikely(system_state == SYSTEM_BOOTING))
  		return notifier_chain_register(&nh->head, n);
  
  	mutex_lock(&nh->mutex);
  	ret = notifier_chain_register(&nh->head, n);
  	mutex_unlock(&nh->mutex);
  	return ret;
  }
  
  EXPORT_SYMBOL_GPL(srcu_notifier_chain_register);
  
  /**
   *	srcu_notifier_chain_unregister - Remove notifier from an SRCU notifier chain
   *	@nh: Pointer to head of the SRCU notifier chain
   *	@n: Entry to remove from notifier chain
   *
   *	Removes a notifier from an SRCU notifier chain.
   *	Must be called from process context.
   *
   *	Returns zero on success or %-ENOENT on failure.
   */
  int srcu_notifier_chain_unregister(struct srcu_notifier_head *nh,
  		struct notifier_block *n)
  {
  	int ret;
  
  	/*
  	 * This code gets used during boot-up, when task switching is
  	 * not yet working and interrupts must remain disabled.  At
  	 * such times we must not call mutex_lock().
  	 */
  	if (unlikely(system_state == SYSTEM_BOOTING))
  		return notifier_chain_unregister(&nh->head, n);
  
  	mutex_lock(&nh->mutex);
  	ret = notifier_chain_unregister(&nh->head, n);
  	mutex_unlock(&nh->mutex);
  	synchronize_srcu(&nh->srcu);
  	return ret;
  }
  
  EXPORT_SYMBOL_GPL(srcu_notifier_chain_unregister);
  
  /**
   *	srcu_notifier_call_chain - Call functions in an SRCU notifier chain
   *	@nh: Pointer to head of the SRCU notifier chain
   *	@val: Value passed unmodified to notifier function
   *	@v: Pointer passed unmodified to notifier function
   *
   *	Calls each function in a notifier chain in turn.  The functions
   *	run in a process context, so they are allowed to block.
   *
   *	If the return value of the notifier can be and'ed
   *	with %NOTIFY_STOP_MASK then srcu_notifier_call_chain
   *	will return immediately, with the return value of
   *	the notifier function which halted execution.
   *	Otherwise the return value is the return value
   *	of the last notifier function called.
   */
  
  int srcu_notifier_call_chain(struct srcu_notifier_head *nh,
  		unsigned long val, void *v)
  {
  	int ret;
  	int idx;
  
  	idx = srcu_read_lock(&nh->srcu);
  	ret = notifier_call_chain(&nh->head, val, v);
  	srcu_read_unlock(&nh->srcu, idx);
  	return ret;
  }
  
  EXPORT_SYMBOL_GPL(srcu_notifier_call_chain);
  
  /**
   *	srcu_init_notifier_head - Initialize an SRCU notifier head
   *	@nh: Pointer to head of the srcu notifier chain
   *
   *	Unlike other sorts of notifier heads, SRCU notifier heads require
   *	dynamic initialization.  Be sure to call this routine before
   *	calling any of the other SRCU notifier routines for this head.
   *
   *	If an SRCU notifier head is deallocated, it must first be cleaned
   *	up by calling srcu_cleanup_notifier_head().  Otherwise the head's
   *	per-cpu data (used by the SRCU mechanism) will leak.
   */
  
  void srcu_init_notifier_head(struct srcu_notifier_head *nh)
  {
  	mutex_init(&nh->mutex);

  	if (init_srcu_struct(&nh->srcu) < 0)
  		BUG();

  	nh->head = NULL;
  }
  
  EXPORT_SYMBOL_GPL(srcu_init_notifier_head);

  /**
   *	register_reboot_notifier - Register function to be called at reboot time
   *	@nb: Info about notifier function to be called
   *
   *	Registers a function with the list of functions
   *	to be called at reboot time.
   *

   *	Currently always returns zero, as blocking_notifier_chain_register

   *	always returns zero.
   */
   
  int register_reboot_notifier(struct notifier_block * nb)
  {

  	return blocking_notifier_chain_register(&reboot_notifier_list, nb);

  }
  
  EXPORT_SYMBOL(register_reboot_notifier);
  
  /**
   *	unregister_reboot_notifier - Unregister previously registered reboot notifier
   *	@nb: Hook to be unregistered
   *
   *	Unregisters a previously registered reboot
   *	notifier function.
   *
   *	Returns zero on success, or %-ENOENT on failure.
   */
   
  int unregister_reboot_notifier(struct notifier_block * nb)
  {

  	return blocking_notifier_chain_unregister(&reboot_notifier_list, nb);

  }
  
  EXPORT_SYMBOL(unregister_reboot_notifier);
  
  static int set_one_prio(struct task_struct *p, int niceval, int error)
  {
  	int no_nice;
  
  	if (p->uid != current->euid &&
  		p->euid != current->euid && !capable(CAP_SYS_NICE)) {
  		error = -EPERM;
  		goto out;
  	}

  	if (niceval < task_nice(p) && !can_nice(p, niceval)) {

  		error = -EACCES;
  		goto out;
  	}
  	no_nice = security_task_setnice(p, niceval);
  	if (no_nice) {
  		error = no_nice;
  		goto out;
  	}
  	if (error == -ESRCH)
  		error = 0;
  	set_user_nice(p, niceval);
  out:
  	return error;
  }
  
  asmlinkage long sys_setpriority(int which, int who, int niceval)
  {
  	struct task_struct *g, *p;
  	struct user_struct *user;
  	int error = -EINVAL;
  
  	if (which > 2 || which < 0)
  		goto out;
  
  	/* normalize: avoid signed division (rounding problems) */
  	error = -ESRCH;
  	if (niceval < -20)
  		niceval = -20;
  	if (niceval > 19)
  		niceval = 19;
  
  	read_lock(&tasklist_lock);
  	switch (which) {
  		case PRIO_PROCESS:
  			if (!who)
  				who = current->pid;
  			p = find_task_by_pid(who);
  			if (p)
  				error = set_one_prio(p, niceval, error);
  			break;
  		case PRIO_PGRP:
  			if (!who)
  				who = process_group(current);
  			do_each_task_pid(who, PIDTYPE_PGID, p) {
  				error = set_one_prio(p, niceval, error);
  			} while_each_task_pid(who, PIDTYPE_PGID, p);
  			break;
  		case PRIO_USER:
  			user = current->user;
  			if (!who)
  				who = current->uid;
  			else
  				if ((who != current->uid) && !(user = find_user(who)))
  					goto out_unlock;	/* No processes for this user */
  
  			do_each_thread(g, p)
  				if (p->uid == who)
  					error = set_one_prio(p, niceval, error);
  			while_each_thread(g, p);
  			if (who != current->uid)
  				free_uid(user);		/* For find_user() */
  			break;
  	}
  out_unlock:
  	read_unlock(&tasklist_lock);
  out:
  	return error;
  }
  
  /*
   * Ugh. To avoid negative return values, "getpriority()" will
   * not return the normal nice-value, but a negated value that
   * has been offset by 20 (ie it returns 40..1 instead of -20..19)
   * to stay compatible.
   */
  asmlinkage long sys_getpriority(int which, int who)
  {
  	struct task_struct *g, *p;
  	struct user_struct *user;
  	long niceval, retval = -ESRCH;
  
  	if (which > 2 || which < 0)
  		return -EINVAL;
  
  	read_lock(&tasklist_lock);
  	switch (which) {
  		case PRIO_PROCESS:
  			if (!who)
  				who = current->pid;
  			p = find_task_by_pid(who);
  			if (p) {
  				niceval = 20 - task_nice(p);
  				if (niceval > retval)
  					retval = niceval;
  			}
  			break;
  		case PRIO_PGRP:
  			if (!who)
  				who = process_group(current);
  			do_each_task_pid(who, PIDTYPE_PGID, p) {
  				niceval = 20 - task_nice(p);
  				if (niceval > retval)
  					retval = niceval;
  			} while_each_task_pid(who, PIDTYPE_PGID, p);
  			break;
  		case PRIO_USER:
  			user = current->user;
  			if (!who)
  				who = current->uid;
  			else
  				if ((who != current->uid) && !(user = find_user(who)))
  					goto out_unlock;	/* No processes for this user */
  
  			do_each_thread(g, p)
  				if (p->uid == who) {
  					niceval = 20 - task_nice(p);
  					if (niceval > retval)
  						retval = niceval;
  				}
  			while_each_thread(g, p);
  			if (who != current->uid)
  				free_uid(user);		/* for find_user() */
  			break;
  	}
  out_unlock:
  	read_unlock(&tasklist_lock);
  
  	return retval;
  }

  /**
   *	emergency_restart - reboot the system
   *
   *	Without shutting down any hardware or taking any locks
   *	reboot the system.  This is called when we know we are in
   *	trouble so this is our best effort to reboot.  This is
   *	safe to call in interrupt context.
   */

  void emergency_restart(void)
  {
  	machine_emergency_restart();
  }
  EXPORT_SYMBOL_GPL(emergency_restart);

  static void kernel_restart_prepare(char *cmd)

  {

  	blocking_notifier_call_chain(&reboot_notifier_list, SYS_RESTART, cmd);

  	system_state = SYSTEM_RESTART;

  	device_shutdown();

  }

  
  /**
   *	kernel_restart - reboot the system
   *	@cmd: pointer to buffer containing command to execute for restart

   *		or %NULL

   *
   *	Shutdown everything and perform a clean reboot.
   *	This is not safe to call in interrupt context.
   */

  void kernel_restart(char *cmd)
  {
  	kernel_restart_prepare(cmd);

  	if (!cmd)

  		printk(KERN_EMERG "Restarting system.
  ");

  	else

  		printk(KERN_EMERG "Restarting system with command '%s'.
  ", cmd);

  	machine_restart(cmd);
  }
  EXPORT_SYMBOL_GPL(kernel_restart);

  /**
   *	kernel_kexec - reboot the system
   *
   *	Move into place and start executing a preloaded standalone
   *	executable.  If nothing was preloaded return an error.
   */

  static void kernel_kexec(void)

  {
  #ifdef CONFIG_KEXEC
  	struct kimage *image;

  	image = xchg(&kexec_image, NULL);

  	if (!image)

  		return;

  	kernel_restart_prepare(NULL);

  	printk(KERN_EMERG "Starting new kernel
  ");
  	machine_shutdown();
  	machine_kexec(image);
  #endif
  }

  void kernel_shutdown_prepare(enum system_states state)
  {

  	blocking_notifier_call_chain(&reboot_notifier_list,

  		(state == SYSTEM_HALT)?SYS_HALT:SYS_POWER_OFF, NULL);
  	system_state = state;
  	device_shutdown();
  }

  /**
   *	kernel_halt - halt the system
   *
   *	Shutdown everything and perform a clean system halt.
   */

  void kernel_halt(void)
  {

  	kernel_shutdown_prepare(SYSTEM_HALT);

  	printk(KERN_EMERG "System halted.
  ");
  	machine_halt();
  }

  EXPORT_SYMBOL_GPL(kernel_halt);

  /**
   *	kernel_power_off - power_off the system
   *
   *	Shutdown everything and perform a clean system power_off.
   */

  void kernel_power_off(void)
  {

  	kernel_shutdown_prepare(SYSTEM_POWER_OFF);

  	printk(KERN_EMERG "Power down.
  ");
  	machine_power_off();
  }
  EXPORT_SYMBOL_GPL(kernel_power_off);

  /*
   * Reboot system call: for obvious reasons only root may call it,
   * and even root needs to set up some magic numbers in the registers
   * so that some mistake won't make this reboot the whole machine.
   * You can also set the meaning of the ctrl-alt-del-key here.
   *
   * reboot doesn't sync: do that yourself before calling this.
   */
  asmlinkage long sys_reboot(int magic1, int magic2, unsigned int cmd, void __user * arg)
  {
  	char buffer[256];
  
  	/* We only trust the superuser with rebooting the system. */
  	if (!capable(CAP_SYS_BOOT))
  		return -EPERM;
  
  	/* For safety, we require "magic" arguments. */
  	if (magic1 != LINUX_REBOOT_MAGIC1 ||
  	    (magic2 != LINUX_REBOOT_MAGIC2 &&
  	                magic2 != LINUX_REBOOT_MAGIC2A &&
  			magic2 != LINUX_REBOOT_MAGIC2B &&
  	                magic2 != LINUX_REBOOT_MAGIC2C))
  		return -EINVAL;

  	/* Instead of trying to make the power_off code look like
  	 * halt when pm_power_off is not set do it the easy way.
  	 */
  	if ((cmd == LINUX_REBOOT_CMD_POWER_OFF) && !pm_power_off)
  		cmd = LINUX_REBOOT_CMD_HALT;

  	lock_kernel();
  	switch (cmd) {
  	case LINUX_REBOOT_CMD_RESTART:

  		kernel_restart(NULL);

  		break;
  
  	case LINUX_REBOOT_CMD_CAD_ON:
  		C_A_D = 1;
  		break;
  
  	case LINUX_REBOOT_CMD_CAD_OFF:
  		C_A_D = 0;
  		break;
  
  	case LINUX_REBOOT_CMD_HALT:

  		kernel_halt();

  		unlock_kernel();
  		do_exit(0);
  		break;
  
  	case LINUX_REBOOT_CMD_POWER_OFF:

  		kernel_power_off();

  		unlock_kernel();
  		do_exit(0);
  		break;
  
  	case LINUX_REBOOT_CMD_RESTART2:
  		if (strncpy_from_user(&buffer[0], arg, sizeof(buffer) - 1) < 0) {
  			unlock_kernel();
  			return -EFAULT;
  		}
  		buffer[sizeof(buffer) - 1] = '\0';

  		kernel_restart(buffer);

  		break;

  	case LINUX_REBOOT_CMD_KEXEC:

  		kernel_kexec();
  		unlock_kernel();
  		return -EINVAL;

  #ifdef CONFIG_SOFTWARE_SUSPEND
  	case LINUX_REBOOT_CMD_SW_SUSPEND:
  		{
  			int ret = software_suspend();
  			unlock_kernel();
  			return ret;
  		}
  #endif
  
  	default:
  		unlock_kernel();
  		return -EINVAL;
  	}
  	unlock_kernel();
  	return 0;
  }
  
  static void deferred_cad(void *dummy)
  {

  	kernel_restart(NULL);

  }
  
  /*
   * This function gets called by ctrl-alt-del - ie the keyboard interrupt.
   * As it's called within an interrupt, it may NOT sync: the only choice
   * is whether to reboot at once, or just ignore the ctrl-alt-del.
   */
  void ctrl_alt_del(void)
  {
  	static DECLARE_WORK(cad_work, deferred_cad, NULL);
  
  	if (C_A_D)
  		schedule_work(&cad_work);
  	else

  		kill_cad_pid(SIGINT, 1);

  }
  	

  /*
   * Unprivileged users may change the real gid to the effective gid
   * or vice versa.  (BSD-style)
   *
   * If you set the real gid at all, or set the effective gid to a value not
   * equal to the real gid, then the saved gid is set to the new effective gid.
   *
   * This makes it possible for a setgid program to completely drop its
   * privileges, which is often a useful assertion to make when you are doing
   * a security audit over a program.
   *
   * The general idea is that a program which uses just setregid() will be
   * 100% compatible with BSD.  A program which uses just setgid() will be
   * 100% compatible with POSIX with saved IDs. 
   *
   * SMP: There are not races, the GIDs are checked only by filesystem
   *      operations (as far as semantic preservation is concerned).
   */
  asmlinkage long sys_setregid(gid_t rgid, gid_t egid)
  {
  	int old_rgid = current->gid;
  	int old_egid = current->egid;
  	int new_rgid = old_rgid;
  	int new_egid = old_egid;
  	int retval;
  
  	retval = security_task_setgid(rgid, egid, (gid_t)-1, LSM_SETID_RE);
  	if (retval)
  		return retval;
  
  	if (rgid != (gid_t) -1) {
  		if ((old_rgid == rgid) ||
  		    (current->egid==rgid) ||
  		    capable(CAP_SETGID))
  			new_rgid = rgid;
  		else
  			return -EPERM;
  	}
  	if (egid != (gid_t) -1) {
  		if ((old_rgid == egid) ||
  		    (current->egid == egid) ||
  		    (current->sgid == egid) ||
  		    capable(CAP_SETGID))
  			new_egid = egid;

  		else

  			return -EPERM;

  	}

  	if (new_egid != old_egid) {

  		current->mm->dumpable = suid_dumpable;

  		smp_wmb();

  	}
  	if (rgid != (gid_t) -1 ||
  	    (egid != (gid_t) -1 && egid != old_rgid))
  		current->sgid = new_egid;
  	current->fsgid = new_egid;
  	current->egid = new_egid;
  	current->gid = new_rgid;
  	key_fsgid_changed(current);

  	proc_id_connector(current, PROC_EVENT_GID);

  	return 0;
  }
  
  /*
   * setgid() is implemented like SysV w/ SAVED_IDS 
   *
   * SMP: Same implicit races as above.
   */
  asmlinkage long sys_setgid(gid_t gid)
  {
  	int old_egid = current->egid;
  	int retval;
  
  	retval = security_task_setgid(gid, (gid_t)-1, (gid_t)-1, LSM_SETID_ID);
  	if (retval)
  		return retval;

  	if (capable(CAP_SETGID)) {
  		if (old_egid != gid) {

  			current->mm->dumpable = suid_dumpable;

  			smp_wmb();

  		}
  		current->gid = current->egid = current->sgid = current->fsgid = gid;

  	} else if ((gid == current->gid) || (gid == current->sgid)) {
  		if (old_egid != gid) {

  			current->mm->dumpable = suid_dumpable;

  			smp_wmb();

  		}
  		current->egid = current->fsgid = gid;
  	}
  	else
  		return -EPERM;
  
  	key_fsgid_changed(current);

  	proc_id_connector(current, PROC_EVENT_GID);

  	return 0;
  }
    
  static int set_user(uid_t new_ruid, int dumpclear)
  {
  	struct user_struct *new_user;
  
  	new_user = alloc_uid(new_ruid);
  	if (!new_user)
  		return -EAGAIN;
  
  	if (atomic_read(&new_user->processes) >=
  				current->signal->rlim[RLIMIT_NPROC].rlim_cur &&
  			new_user != &root_user) {
  		free_uid(new_user);
  		return -EAGAIN;
  	}
  
  	switch_uid(new_user);

  	if (dumpclear) {

  		current->mm->dumpable = suid_dumpable;

  		smp_wmb();

  	}
  	current->uid = new_ruid;
  	return 0;
  }
  
  /*
   * Unprivileged users may change the real uid to the effective uid
   * or vice versa.  (BSD-style)
   *
   * If you set the real uid at all, or set the effective uid to a value not
   * equal to the real uid, then the saved uid is set to the new effective uid.
   *
   * This makes it possible for a setuid program to completely drop its
   * privileges, which is often a useful assertion to make when you are doing
   * a security audit over a program.
   *
   * The general idea is that a program which uses just setreuid() will be
   * 100% compatible with BSD.  A program which uses just setuid() will be
   * 100% compatible with POSIX with saved IDs. 
   */
  asmlinkage long sys_setreuid(uid_t ruid, uid_t euid)
  {
  	int old_ruid, old_euid, old_suid, new_ruid, new_euid;
  	int retval;
  
  	retval = security_task_setuid(ruid, euid, (uid_t)-1, LSM_SETID_RE);
  	if (retval)
  		return retval;
  
  	new_ruid = old_ruid = current->uid;
  	new_euid = old_euid = current->euid;
  	old_suid = current->suid;
  
  	if (ruid != (uid_t) -1) {
  		new_ruid = ruid;
  		if ((old_ruid != ruid) &&
  		    (current->euid != ruid) &&
  		    !capable(CAP_SETUID))
  			return -EPERM;
  	}
  
  	if (euid != (uid_t) -1) {
  		new_euid = euid;
  		if ((old_ruid != euid) &&
  		    (current->euid != euid) &&
  		    (current->suid != euid) &&
  		    !capable(CAP_SETUID))
  			return -EPERM;
  	}
  
  	if (new_ruid != old_ruid && set_user(new_ruid, new_euid != old_euid) < 0)
  		return -EAGAIN;

  	if (new_euid != old_euid) {

  		current->mm->dumpable = suid_dumpable;

  		smp_wmb();

  	}
  	current->fsuid = current->euid = new_euid;
  	if (ruid != (uid_t) -1 ||
  	    (euid != (uid_t) -1 && euid != old_ruid))
  		current->suid = current->euid;
  	current->fsuid = current->euid;
  
  	key_fsuid_changed(current);

  	proc_id_connector(current, PROC_EVENT_UID);

  
  	return security_task_post_setuid(old_ruid, old_euid, old_suid, LSM_SETID_RE);
  }
  
  
  		
  /*
   * setuid() is implemented like SysV with SAVED_IDS 
   * 
   * Note that SAVED_ID's is deficient in that a setuid root program
   * like sendmail, for example, cannot set its uid to be a normal 
   * user and then switch back, because if you're root, setuid() sets
   * the saved uid too.  If you don't like this, blame the bright people
   * in the POSIX committee and/or USG.  Note that the BSD-style setreuid()
   * will allow a root program to temporarily drop privileges and be able to
   * regain them by swapping the real and effective uid.  
   */
  asmlinkage long sys_setuid(uid_t uid)
  {
  	int old_euid = current->euid;
  	int old_ruid, old_suid, new_ruid, new_suid;
  	int retval;
  
  	retval = security_task_setuid(uid, (uid_t)-1, (uid_t)-1, LSM_SETID_ID);
  	if (retval)
  		return retval;
  
  	old_ruid = new_ruid = current->uid;
  	old_suid = current->suid;
  	new_suid = old_suid;
  	
  	if (capable(CAP_SETUID)) {
  		if (uid != old_ruid && set_user(uid, old_euid != uid) < 0)
  			return -EAGAIN;
  		new_suid = uid;
  	} else if ((uid != current->uid) && (uid != new_suid))
  		return -EPERM;

  	if (old_euid != uid) {

  		current->mm->dumpable = suid_dumpable;

  		smp_wmb();

  	}
  	current->fsuid = current->euid = uid;
  	current->suid = new_suid;
  
  	key_fsuid_changed(current);

  	proc_id_connector(current, PROC_EVENT_UID);

  
  	return security_task_post_setuid(old_ruid, old_euid, old_suid, LSM_SETID_ID);
  }
  
  
  /*
   * This function implements a generic ability to update ruid, euid,
   * and suid.  This allows you to implement the 4.4 compatible seteuid().
   */
  asmlinkage long sys_setresuid(uid_t ruid, uid_t euid, uid_t suid)
  {
  	int old_ruid = current->uid;
  	int old_euid = current->euid;
  	int old_suid = current->suid;
  	int retval;
  
  	retval = security_task_setuid(ruid, euid, suid, LSM_SETID_RES);
  	if (retval)
  		return retval;
  
  	if (!capable(CAP_SETUID)) {
  		if ((ruid != (uid_t) -1) && (ruid != current->uid) &&
  		    (ruid != current->euid) && (ruid != current->suid))
  			return -EPERM;
  		if ((euid != (uid_t) -1) && (euid != current->uid) &&
  		    (euid != current->euid) && (euid != current->suid))
  			return -EPERM;
  		if ((suid != (uid_t) -1) && (suid != current->uid) &&
  		    (suid != current->euid) && (suid != current->suid))
  			return -EPERM;
  	}
  	if (ruid != (uid_t) -1) {
  		if (ruid != current->uid && set_user(ruid, euid != current->euid) < 0)
  			return -EAGAIN;
  	}
  	if (euid != (uid_t) -1) {

  		if (euid != current->euid) {

  			current->mm->dumpable = suid_dumpable;

  			smp_wmb();

  		}
  		current->euid = euid;
  	}
  	current->fsuid = current->euid;
  	if (suid != (uid_t) -1)
  		current->suid = suid;
  
  	key_fsuid_changed(current);

  	proc_id_connector(current, PROC_EVENT_UID);

  
  	return security_task_post_setuid(old_ruid, old_euid, old_suid, LSM_SETID_RES);
  }
  
  asmlinkage long sys_getresuid(uid_t __user *ruid, uid_t __user *euid, uid_t __user *suid)
  {
  	int retval;
  
  	if (!(retval = put_user(current->uid, ruid)) &&
  	    !(retval = put_user(current->euid, euid)))
  		retval = put_user(current->suid, suid);
  
  	return retval;
  }
  
  /*
   * Same as above, but for rgid, egid, sgid.
   */
  asmlinkage long sys_setresgid(gid_t rgid, gid_t egid, gid_t sgid)
  {
  	int retval;
  
  	retval = security_task_setgid(rgid, egid, sgid, LSM_SETID_RES);
  	if (retval)
  		return retval;
  
  	if (!capable(CAP_SETGID)) {
  		if ((rgid != (gid_t) -1) && (rgid != current->gid) &&
  		    (rgid != current->egid) && (rgid != current->sgid))
  			return -EPERM;
  		if ((egid != (gid_t) -1) && (egid != current->gid) &&
  		    (egid != current->egid) && (egid != current->sgid))
  			return -EPERM;
  		if ((sgid != (gid_t) -1) && (sgid != current->gid) &&
  		    (sgid != current->egid) && (sgid != current->sgid))
  			return -EPERM;
  	}
  	if (egid != (gid_t) -1) {

  		if (egid != current->egid) {

  			current->mm->dumpable = suid_dumpable;

  			smp_wmb();

  		}
  		current->egid = egid;
  	}
  	current->fsgid = current->egid;
  	if (rgid != (gid_t) -1)
  		current->gid = rgid;
  	if (sgid != (gid_t) -1)
  		current->sgid = sgid;
  
  	key_fsgid_changed(current);

  	proc_id_connector(current, PROC_EVENT_GID);

  	return 0;
  }
  
  asmlinkage long sys_getresgid(gid_t __user *rgid, gid_t __user *egid, gid_t __user *sgid)
  {
  	int retval;
  
  	if (!(retval = put_user(current->gid, rgid)) &&
  	    !(retval = put_user(current->egid, egid)))
  		retval = put_user(current->sgid, sgid);
  
  	return retval;
  }
  
  
  /*
   * "setfsuid()" sets the fsuid - the uid used for filesystem checks. This
   * is used for "access()" and for the NFS daemon (letting nfsd stay at
   * whatever uid it wants to). It normally shadows "euid", except when
   * explicitly set by setfsuid() or for access..
   */
  asmlinkage long sys_setfsuid(uid_t uid)
  {
  	int old_fsuid;
  
  	old_fsuid = current->fsuid;
  	if (security_task_setuid(uid, (uid_t)-1, (uid_t)-1, LSM_SETID_FS))
  		return old_fsuid;
  
  	if (uid == current->uid || uid == current->euid ||
  	    uid == current->suid || uid == current->fsuid || 

  	    capable(CAP_SETUID)) {
  		if (uid != old_fsuid) {

  			current->mm->dumpable = suid_dumpable;

  			smp_wmb();

  		}
  		current->fsuid = uid;
  	}
  
  	key_fsuid_changed(current);

  	proc_id_connector(current, PROC_EVENT_UID);

  
  	security_task_post_setuid(old_fsuid, (uid_t)-1, (uid_t)-1, LSM_SETID_FS);
  
  	return old_fsuid;
  }
  
  /*
   * Samma på svenska..
   */
  asmlinkage long sys_setfsgid(gid_t gid)
  {
  	int old_fsgid;
  
  	old_fsgid = current->fsgid;
  	if (security_task_setgid(gid, (gid_t)-1, (gid_t)-1, LSM_SETID_FS))
  		return old_fsgid;
  
  	if (gid == current->gid || gid == current->egid ||
  	    gid == current->sgid || gid == current->fsgid || 

  	    capable(CAP_SETGID)) {
  		if (gid != old_fsgid) {

  			current->mm->dumpable = suid_dumpable;

  			smp_wmb();

  		}
  		current->fsgid = gid;
  		key_fsgid_changed(current);

  		proc_id_connector(current, PROC_EVENT_GID);

  	}
  	return old_fsgid;
  }
  
  asmlinkage long sys_times(struct tms __user * tbuf)
  {
  	/*
  	 *	In the SMP world we might just be unlucky and have one of
  	 *	the times increment as we use it. Since the value is an
  	 *	atomically safe type this is just fine. Conceptually its
  	 *	as if the syscall took an instant longer to occur.
  	 */
  	if (tbuf) {
  		struct tms tmp;

  		struct task_struct *tsk = current;
  		struct task_struct *t;

  		cputime_t utime, stime, cutime, cstime;

  		spin_lock_irq(&tsk->sighand->siglock);

  		utime = tsk->signal->utime;
  		stime = tsk->signal->stime;
  		t = tsk;
  		do {
  			utime = cputime_add(utime, t->utime);
  			stime = cputime_add(stime, t->stime);
  			t = next_thread(t);
  		} while (t != tsk);

  		cutime = tsk->signal->cutime;
  		cstime = tsk->signal->cstime;
  		spin_unlock_irq(&tsk->sighand->siglock);

  
  		tmp.tms_utime = cputime_to_clock_t(utime);
  		tmp.tms_stime = cputime_to_clock_t(stime);
  		tmp.tms_cutime = cputime_to_clock_t(cutime);
  		tmp.tms_cstime = cputime_to_clock_t(cstime);
  		if (copy_to_user(tbuf, &tmp, sizeof(struct tms)))
  			return -EFAULT;
  	}
  	return (long) jiffies_64_to_clock_t(get_jiffies_64());
  }
  
  /*
   * This needs some heavy checking ...
   * I just haven't the stomach for it. I also don't fully
   * understand sessions/pgrp etc. Let somebody who does explain it.
   *
   * OK, I think I have the protection semantics right.... this is really
   * only important on a multi-user system anyway, to make sure one user
   * can't send a signal to a process owned by another.  -TYT, 12/12/91
   *
   * Auch. Had to add the 'did_exec' flag to conform completely to POSIX.
   * LBT 04.03.94
   */
  
  asmlinkage long sys_setpgid(pid_t pid, pid_t pgid)
  {
  	struct task_struct *p;

  	struct task_struct *group_leader = current->group_leader;

  	int err = -EINVAL;
  
  	if (!pid)

  		pid = group_leader->pid;

  	if (!pgid)
  		pgid = pid;
  	if (pgid < 0)
  		return -EINVAL;
  
  	/* From this point forward we keep holding onto the tasklist lock
  	 * so that our parent does not change from under us. -DaveM
  	 */
  	write_lock_irq(&tasklist_lock);
  
  	err = -ESRCH;
  	p = find_task_by_pid(pid);
  	if (!p)
  		goto out;
  
  	err = -EINVAL;
  	if (!thread_group_leader(p))
  		goto out;

  	if (p->real_parent == group_leader) {

  		err = -EPERM;

  		if (p->signal->session != group_leader->signal->session)

  			goto out;
  		err = -EACCES;
  		if (p->did_exec)
  			goto out;
  	} else {
  		err = -ESRCH;

  		if (p != group_leader)

  			goto out;
  	}
  
  	err = -EPERM;
  	if (p->signal->leader)
  		goto out;
  
  	if (pgid != pid) {
  		struct task_struct *p;
  
  		do_each_task_pid(pgid, PIDTYPE_PGID, p) {

  			if (p->signal->session == group_leader->signal->session)

  				goto ok_pgid;
  		} while_each_task_pid(pgid, PIDTYPE_PGID, p);
  		goto out;
  	}
  
  ok_pgid:
  	err = security_task_setpgid(p, pgid);
  	if (err)
  		goto out;
  
  	if (process_group(p) != pgid) {
  		detach_pid(p, PIDTYPE_PGID);
  		p->signal->pgrp = pgid;
  		attach_pid(p, PIDTYPE_PGID, pgid);
  	}
  
  	err = 0;
  out:
  	/* All paths lead to here, thus we are safe. -DaveM */
  	write_unlock_irq(&tasklist_lock);
  	return err;
  }
  
  asmlinkage long sys_getpgid(pid_t pid)
  {

  	if (!pid)

  		return process_group(current);

  	else {

  		int retval;
  		struct task_struct *p;
  
  		read_lock(&tasklist_lock);
  		p = find_task_by_pid(pid);
  
  		retval = -ESRCH;
  		if (p) {
  			retval = security_task_getpgid(p);
  			if (!retval)
  				retval = process_group(p);
  		}
  		read_unlock(&tasklist_lock);
  		return retval;
  	}
  }
  
  #ifdef __ARCH_WANT_SYS_GETPGRP
  
  asmlinkage long sys_getpgrp(void)
  {
  	/* SMP - assuming writes are word atomic this is fine */
  	return process_group(current);
  }
  
  #endif
  
  asmlinkage long sys_getsid(pid_t pid)
  {

  	if (!pid)

  		return current->signal->session;

  	else {

  		int retval;
  		struct task_struct *p;
  
  		read_lock(&tasklist_lock);
  		p = find_task_by_pid(pid);
  
  		retval = -ESRCH;

  		if (p) {

  			retval = security_task_getsid(p);
  			if (!retval)
  				retval = p->signal->session;
  		}
  		read_unlock(&tasklist_lock);
  		return retval;
  	}
  }
  
  asmlinkage long sys_setsid(void)
  {

  	struct task_struct *group_leader = current->group_leader;

  	pid_t session;

  	int err = -EPERM;

  	mutex_lock(&tty_mutex);

  	write_lock_irq(&tasklist_lock);

  	/* Fail if I am already a session leader */
  	if (group_leader->signal->leader)
  		goto out;
  
  	session = group_leader->pid;
  	/* Fail if a process group id already exists that equals the
  	 * proposed session id.
  	 *
  	 * Don't check if session id == 1 because kernel threads use this
  	 * session id and so the check will always fail and make it so
  	 * init cannot successfully call setsid.
  	 */
  	if (session > 1 && find_task_by_pid_type(PIDTYPE_PGID, session))

  		goto out;

  	group_leader->signal->leader = 1;

  	__set_special_pids(session, session);

  	group_leader->signal->tty = NULL;
  	group_leader->signal->tty_old_pgrp = 0;
  	err = process_group(group_leader);

  out:
  	write_unlock_irq(&tasklist_lock);

  	mutex_unlock(&tty_mutex);

  	return err;
  }
  
  /*
   * Supplementary group IDs
   */
  
  /* init to 2 - one for init_task, one to ensure it is never freed */
  struct group_info init_groups = { .usage = ATOMIC_INIT(2) };
  
  struct group_info *groups_alloc(int gidsetsize)
  {
  	struct group_info *group_info;
  	int nblocks;
  	int i;
  
  	nblocks = (gidsetsize + NGROUPS_PER_BLOCK - 1) / NGROUPS_PER_BLOCK;
  	/* Make sure we always allocate at least one indirect block pointer */
  	nblocks = nblocks ? : 1;
  	group_info = kmalloc(sizeof(*group_info) + nblocks*sizeof(gid_t *), GFP_USER);
  	if (!group_info)
  		return NULL;
  	group_info->ngroups = gidsetsize;
  	group_info->nblocks = nblocks;
  	atomic_set(&group_info->usage, 1);

  	if (gidsetsize <= NGROUPS_SMALL)

  		group_info->blocks[0] = group_info->small_block;

  	else {

  		for (i = 0; i < nblocks; i++) {
  			gid_t *b;
  			b = (void *)__get_free_page(GFP_USER);
  			if (!b)
  				goto out_undo_partial_alloc;
  			group_info->blocks[i] = b;
  		}
  	}
  	return group_info;
  
  out_undo_partial_alloc:
  	while (--i >= 0) {
  		free_page((unsigned long)group_info->blocks[i]);
  	}
  	kfree(group_info);
  	return NULL;
  }
  
  EXPORT_SYMBOL(groups_alloc);
  
  void groups_free(struct group_info *group_info)
  {
  	if (group_info->blocks[0] != group_info->small_block) {
  		int i;
  		for (i = 0; i < group_info->nblocks; i++)
  			free_page((unsigned long)group_info->blocks[i]);
  	}
  	kfree(group_info);
  }
  
  EXPORT_SYMBOL(groups_free);
  
  /* export the group_info to a user-space array */
  static int groups_to_user(gid_t __user *grouplist,
      struct group_info *group_info)
  {
  	int i;
  	int count = group_info->ngroups;
  
  	for (i = 0; i < group_info->nblocks; i++) {
  		int cp_count = min(NGROUPS_PER_BLOCK, count);
  		int off = i * NGROUPS_PER_BLOCK;
  		int len = cp_count * sizeof(*grouplist);
  
  		if (copy_to_user(grouplist+off, group_info->blocks[i], len))
  			return -EFAULT;
  
  		count -= cp_count;
  	}
  	return 0;
  }
  
  /* fill a group_info from a user-space array - it must be allocated already */
  static int groups_from_user(struct group_info *group_info,
      gid_t __user *grouplist)

  {

  	int i;
  	int count = group_info->ngroups;
  
  	for (i = 0; i < group_info->nblocks; i++) {
  		int cp_count = min(NGROUPS_PER_BLOCK, count);
  		int off = i * NGROUPS_PER_BLOCK;
  		int len = cp_count * sizeof(*grouplist);
  
  		if (copy_from_user(group_info->blocks[i], grouplist+off, len))
  			return -EFAULT;
  
  		count -= cp_count;
  	}
  	return 0;
  }

  /* a simple Shell sort */

  static void groups_sort(struct group_info *group_info)
  {
  	int base, max, stride;
  	int gidsetsize = group_info->ngroups;
  
  	for (stride = 1; stride < gidsetsize; stride = 3 * stride + 1)
  		; /* nothing */
  	stride /= 3;
  
  	while (stride) {
  		max = gidsetsize - stride;
  		for (base = 0; base < max; base++) {
  			int left = base;
  			int right = left + stride;
  			gid_t tmp = GROUP_AT(group_info, right);
  
  			while (left >= 0 && GROUP_AT(group_info, left) > tmp) {
  				GROUP_AT(group_info, right) =
  				    GROUP_AT(group_info, left);
  				right = left;
  				left -= stride;
  			}
  			GROUP_AT(group_info, right) = tmp;
  		}
  		stride /= 3;
  	}
  }
  
  /* a simple bsearch */

  int groups_search(struct group_info *group_info, gid_t grp)

  {

  	unsigned int left, right;

  
  	if (!group_info)
  		return 0;
  
  	left = 0;
  	right = group_info->ngroups;
  	while (left < right) {

  		unsigned int mid = (left+right)/2;

  		int cmp = grp - GROUP_AT(group_info, mid);
  		if (cmp > 0)
  			left = mid + 1;
  		else if (cmp < 0)
  			right = mid;
  		else
  			return 1;
  	}
  	return 0;
  }
  
  /* validate and set current->group_info */
  int set_current_groups(struct group_info *group_info)
  {
  	int retval;
  	struct group_info *old_info;
  
  	retval = security_task_setgroups(group_info);
  	if (retval)
  		return retval;
  
  	groups_sort(group_info);
  	get_group_info(group_info);
  
  	task_lock(current);
  	old_info = current->group_info;
  	current->group_info = group_info;
  	task_unlock(current);
  
  	put_group_info(old_info);
  
  	return 0;
  }
  
  EXPORT_SYMBOL(set_current_groups);
  
  asmlinkage long sys_getgroups(int gidsetsize, gid_t __user *grouplist)
  {
  	int i = 0;
  
  	/*
  	 *	SMP: Nobody else can change our grouplist. Thus we are
  	 *	safe.
  	 */
  
  	if (gidsetsize < 0)
  		return -EINVAL;
  
  	/* no need to grab task_lock here; it cannot change */

  	i = current->group_info->ngroups;
  	if (gidsetsize) {
  		if (i > gidsetsize) {
  			i = -EINVAL;
  			goto out;
  		}
  		if (groups_to_user(grouplist, current->group_info)) {
  			i = -EFAULT;
  			goto out;
  		}
  	}
  out:

  	return i;
  }
  
  /*
   *	SMP: Our groups are copy-on-write. We can set them safely
   *	without another task interfering.
   */
   
  asmlinkage long sys_setgroups(int gidsetsize, gid_t __user *grouplist)
  {
  	struct group_info *group_info;
  	int retval;
  
  	if (!capable(CAP_SETGID))
  		return -EPERM;
  	if ((unsigned)gidsetsize > NGROUPS_MAX)
  		return -EINVAL;
  
  	group_info = groups_alloc(gidsetsize);
  	if (!group_info)
  		return -ENOMEM;
  	retval = groups_from_user(group_info, grouplist);
  	if (retval) {
  		put_group_info(group_info);
  		return retval;
  	}
  
  	retval = set_current_groups(group_info);
  	put_group_info(group_info);
  
  	return retval;
  }
  
  /*
   * Check whether we're fsgid/egid or in the supplemental group..
   */
  int in_group_p(gid_t grp)
  {
  	int retval = 1;

  	if (grp != current->fsgid)

  		retval = groups_search(current->group_info, grp);

  	return retval;
  }
  
  EXPORT_SYMBOL(in_group_p);
  
  int in_egroup_p(gid_t grp)
  {
  	int retval = 1;

  	if (grp != current->egid)

  		retval = groups_search(current->group_info, grp);

  	return retval;
  }
  
  EXPORT_SYMBOL(in_egroup_p);
  
  DECLARE_RWSEM(uts_sem);

  EXPORT_SYMBOL(uts_sem);

  asmlinkage long sys_newuname(struct new_utsname __user * name)
  {
  	int errno = 0;
  
  	down_read(&uts_sem);

  	if (copy_to_user(name, utsname(), sizeof *name))

  		errno = -EFAULT;
  	up_read(&uts_sem);
  	return errno;
  }
  
  asmlinkage long sys_sethostname(char __user *name, int len)
  {
  	int errno;
  	char tmp[__NEW_UTS_LEN];
  
  	if (!capable(CAP_SYS_ADMIN))
  		return -EPERM;
  	if (len < 0 || len > __NEW_UTS_LEN)
  		return -EINVAL;
  	down_write(&uts_sem);
  	errno = -EFAULT;
  	if (!copy_from_user(tmp, name, len)) {

  		memcpy(utsname()->nodename, tmp, len);
  		utsname()->nodename[len] = 0;

  		errno = 0;
  	}
  	up_write(&uts_sem);
  	return errno;
  }
  
  #ifdef __ARCH_WANT_SYS_GETHOSTNAME
  
  asmlinkage long sys_gethostname(char __user *name, int len)
  {
  	int i, errno;
  
  	if (len < 0)
  		return -EINVAL;
  	down_read(&uts_sem);

  	i = 1 + strlen(utsname()->nodename);

  	if (i > len)
  		i = len;
  	errno = 0;

  	if (copy_to_user(name, utsname()->nodename, i))

  		errno = -EFAULT;
  	up_read(&uts_sem);
  	return errno;
  }
  
  #endif
  
  /*
   * Only setdomainname; getdomainname can be implemented by calling
   * uname()
   */
  asmlinkage long sys_setdomainname(char __user *name, int len)
  {
  	int errno;
  	char tmp[__NEW_UTS_LEN];
  
  	if (!capable(CAP_SYS_ADMIN))
  		return -EPERM;
  	if (len < 0 || len > __NEW_UTS_LEN)
  		return -EINVAL;
  
  	down_write(&uts_sem);
  	errno = -EFAULT;
  	if (!copy_from_user(tmp, name, len)) {

  		memcpy(utsname()->domainname, tmp, len);
  		utsname()->domainname[len] = 0;

  		errno = 0;
  	}
  	up_write(&uts_sem);
  	return errno;
  }
  
  asmlinkage long sys_getrlimit(unsigned int resource, struct rlimit __user *rlim)
  {
  	if (resource >= RLIM_NLIMITS)
  		return -EINVAL;
  	else {
  		struct rlimit value;
  		task_lock(current->group_leader);
  		value = current->signal->rlim[resource];
  		task_unlock(current->group_leader);
  		return copy_to_user(rlim, &value, sizeof(*rlim)) ? -EFAULT : 0;
  	}
  }
  
  #ifdef __ARCH_WANT_SYS_OLD_GETRLIMIT
  
  /*
   *	Back compatibility for getrlimit. Needed for some apps.
   */
   
  asmlinkage long sys_old_getrlimit(unsigned int resource, struct rlimit __user *rlim)
  {
  	struct rlimit x;
  	if (resource >= RLIM_NLIMITS)
  		return -EINVAL;
  
  	task_lock(current->group_leader);
  	x = current->signal->rlim[resource];
  	task_unlock(current->group_leader);

  	if (x.rlim_cur > 0x7FFFFFFF)

  		x.rlim_cur = 0x7FFFFFFF;

  	if (x.rlim_max > 0x7FFFFFFF)

  		x.rlim_max = 0x7FFFFFFF;
  	return copy_to_user(rlim, &x, sizeof(x))?-EFAULT:0;
  }
  
  #endif
  
  asmlinkage long sys_setrlimit(unsigned int resource, struct rlimit __user *rlim)
  {
  	struct rlimit new_rlim, *old_rlim;

  	unsigned long it_prof_secs;

  	int retval;
  
  	if (resource >= RLIM_NLIMITS)
  		return -EINVAL;

  	if (copy_from_user(&new_rlim, rlim, sizeof(*rlim)))

  		return -EFAULT;

  	if (new_rlim.rlim_cur > new_rlim.rlim_max)
  		return -EINVAL;

  	old_rlim = current->signal->rlim + resource;
  	if ((new_rlim.rlim_max > old_rlim->rlim_max) &&
  	    !capable(CAP_SYS_RESOURCE))
  		return -EPERM;
  	if (resource == RLIMIT_NOFILE && new_rlim.rlim_max > NR_OPEN)

  		return -EPERM;

  
  	retval = security_task_setrlimit(resource, &new_rlim);
  	if (retval)
  		return retval;
  
  	task_lock(current->group_leader);
  	*old_rlim = new_rlim;
  	task_unlock(current->group_leader);

  	if (resource != RLIMIT_CPU)
  		goto out;

  
  	/*
  	 * RLIMIT_CPU handling.   Note that the kernel fails to return an error
  	 * code if it rejected the user's attempt to set RLIMIT_CPU.  This is a
  	 * very long-standing error, and fixing it now risks breakage of
  	 * applications, so we live with it
  	 */

  	if (new_rlim.rlim_cur == RLIM_INFINITY)
  		goto out;
  
  	it_prof_secs = cputime_to_secs(current->signal->it_prof_expires);
  	if (it_prof_secs == 0 || new_rlim.rlim_cur <= it_prof_secs) {

  		unsigned long rlim_cur = new_rlim.rlim_cur;
  		cputime_t cputime;

  		if (rlim_cur == 0) {
  			/*
  			 * The caller is asking for an immediate RLIMIT_CPU
  			 * expiry.  But we use the zero value to mean "it was
  			 * never set".  So let's cheat and make it one second
  			 * instead
  			 */
  			rlim_cur = 1;
  		}
  		cputime = secs_to_cputime(rlim_cur);

  		read_lock(&tasklist_lock);
  		spin_lock_irq(&current->sighand->siglock);

  		set_process_cpu_timer(current, CPUCLOCK_PROF, &cputime, NULL);

  		spin_unlock_irq(&current->sighand->siglock);
  		read_unlock(&tasklist_lock);
  	}

  out:

  	return 0;
  }
  
  /*
   * It would make sense to put struct rusage in the task_struct,
   * except that would make the task_struct be *really big*.  After
   * task_struct gets moved into malloc'ed memory, it would
   * make sense to do this.  It will make moving the rest of the information
   * a lot simpler!  (Which we're not doing right now because we're not
   * measuring them yet).
   *

   * When sampling multiple threads for RUSAGE_SELF, under SMP we might have
   * races with threads incrementing their own counters.  But since word
   * reads are atomic, we either get new values or old values and we don't
   * care which for the sums.  We always take the siglock to protect reading
   * the c* fields from p->signal from races with exit.c updating those
   * fields when reaping, so a sample either gets all the additions of a
   * given child after it's reaped, or none so this sample is before reaping.

   *

   * Locking:
   * We need to take the siglock for CHILDEREN, SELF and BOTH
   * for  the cases current multithreaded, non-current single threaded
   * non-current multithreaded.  Thread traversal is now safe with
   * the siglock held.
   * Strictly speaking, we donot need to take the siglock if we are current and
   * single threaded,  as no one else can take our signal_struct away, no one
   * else can  reap the  children to update signal->c* counters, and no one else
   * can race with the signal-> fields. If we do not take any lock, the
   * signal-> fields could be read out of order while another thread was just
   * exiting. So we should  place a read memory barrier when we avoid the lock.
   * On the writer side,  write memory barrier is implied in  __exit_signal
   * as __exit_signal releases  the siglock spinlock after updating the signal->
   * fields. But we don't do this yet to keep things simple.

   *

   */
  
  static void k_getrusage(struct task_struct *p, int who, struct rusage *r)
  {
  	struct task_struct *t;
  	unsigned long flags;
  	cputime_t utime, stime;
  
  	memset((char *) r, 0, sizeof *r);

  	utime = stime = cputime_zero;

  	rcu_read_lock();
  	if (!lock_task_sighand(p, &flags)) {
  		rcu_read_unlock();
  		return;
  	}

  	switch (who) {

  		case RUSAGE_BOTH:

  		case RUSAGE_CHILDREN:

  			utime = p->signal->cutime;
  			stime = p->signal->cstime;
  			r->ru_nvcsw = p->signal->cnvcsw;
  			r->ru_nivcsw = p->signal->cnivcsw;
  			r->ru_minflt = p->signal->cmin_flt;
  			r->ru_majflt = p->signal->cmaj_flt;

  
  			if (who == RUSAGE_CHILDREN)
  				break;

  		case RUSAGE_SELF:

  			utime = cputime_add(utime, p->signal->utime);
  			stime = cputime_add(stime, p->signal->stime);
  			r->ru_nvcsw += p->signal->nvcsw;
  			r->ru_nivcsw += p->signal->nivcsw;
  			r->ru_minflt += p->signal->min_flt;
  			r->ru_majflt += p->signal->maj_flt;
  			t = p;
  			do {
  				utime = cputime_add(utime, t->utime);
  				stime = cputime_add(stime, t->stime);
  				r->ru_nvcsw += t->nvcsw;
  				r->ru_nivcsw += t->nivcsw;
  				r->ru_minflt += t->min_flt;
  				r->ru_majflt += t->maj_flt;
  				t = next_thread(t);
  			} while (t != p);

  			break;

  		default:
  			BUG();
  	}

  	unlock_task_sighand(p, &flags);
  	rcu_read_unlock();

  	cputime_to_timeval(utime, &r->ru_utime);
  	cputime_to_timeval(stime, &r->ru_stime);

  }
  
  int getrusage(struct task_struct *p, int who, struct rusage __user *ru)
  {
  	struct rusage r;

  	k_getrusage(p, who, &r);

  	return copy_to_user(ru, &r, sizeof(r)) ? -EFAULT : 0;
  }
  
  asmlinkage long sys_getrusage(int who, struct rusage __user *ru)
  {
  	if (who != RUSAGE_SELF && who != RUSAGE_CHILDREN)
  		return -EINVAL;
  	return getrusage(current, who, ru);
  }
  
  asmlinkage long sys_umask(int mask)
  {
  	mask = xchg(&current->fs->umask, mask & S_IRWXUGO);
  	return mask;
  }
      
  asmlinkage long sys_prctl(int option, unsigned long arg2, unsigned long arg3,
  			  unsigned long arg4, unsigned long arg5)
  {
  	long error;

  
  	error = security_task_prctl(option, arg2, arg3, arg4, arg5);
  	if (error)
  		return error;
  
  	switch (option) {
  		case PR_SET_PDEATHSIG:

  			if (!valid_signal(arg2)) {

  				error = -EINVAL;
  				break;
  			}

  			current->pdeath_signal = arg2;

  			break;
  		case PR_GET_PDEATHSIG:
  			error = put_user(current->pdeath_signal, (int __user *)arg2);
  			break;
  		case PR_GET_DUMPABLE:

  			error = current->mm->dumpable;

  			break;
  		case PR_SET_DUMPABLE:

  			if (arg2 < 0 || arg2 > 1) {

  				error = -EINVAL;
  				break;
  			}
  			current->mm->dumpable = arg2;
  			break;
  
  		case PR_SET_UNALIGN:
  			error = SET_UNALIGN_CTL(current, arg2);
  			break;
  		case PR_GET_UNALIGN:
  			error = GET_UNALIGN_CTL(current, arg2);
  			break;
  		case PR_SET_FPEMU:
  			error = SET_FPEMU_CTL(current, arg2);
  			break;
  		case PR_GET_FPEMU:
  			error = GET_FPEMU_CTL(current, arg2);
  			break;
  		case PR_SET_FPEXC:
  			error = SET_FPEXC_CTL(current, arg2);
  			break;
  		case PR_GET_FPEXC:
  			error = GET_FPEXC_CTL(current, arg2);
  			break;
  		case PR_GET_TIMING:
  			error = PR_TIMING_STATISTICAL;
  			break;
  		case PR_SET_TIMING:
  			if (arg2 == PR_TIMING_STATISTICAL)
  				error = 0;
  			else
  				error = -EINVAL;
  			break;
  
  		case PR_GET_KEEPCAPS:
  			if (current->keep_capabilities)
  				error = 1;
  			break;
  		case PR_SET_KEEPCAPS:
  			if (arg2 != 0 && arg2 != 1) {
  				error = -EINVAL;
  				break;
  			}
  			current->keep_capabilities = arg2;
  			break;
  		case PR_SET_NAME: {
  			struct task_struct *me = current;
  			unsigned char ncomm[sizeof(me->comm)];
  
  			ncomm[sizeof(me->comm)-1] = 0;
  			if (strncpy_from_user(ncomm, (char __user *)arg2,
  						sizeof(me->comm)-1) < 0)
  				return -EFAULT;
  			set_task_comm(me, ncomm);
  			return 0;
  		}
  		case PR_GET_NAME: {
  			struct task_struct *me = current;
  			unsigned char tcomm[sizeof(me->comm)];
  
  			get_task_comm(tcomm, me);
  			if (copy_to_user((char __user *)arg2, tcomm, sizeof(tcomm)))
  				return -EFAULT;
  			return 0;
  		}

  		case PR_GET_ENDIAN:
  			error = GET_ENDIAN(current, arg2);
  			break;
  		case PR_SET_ENDIAN:
  			error = SET_ENDIAN(current, arg2);
  			break;

  		default:
  			error = -EINVAL;
  			break;
  	}
  	return error;
  }

  
  asmlinkage long sys_getcpu(unsigned __user *cpup, unsigned __user *nodep,
  	   		   struct getcpu_cache __user *cache)
  {
  	int err = 0;
  	int cpu = raw_smp_processor_id();
  	if (cpup)
  		err |= put_user(cpu, cpup);
  	if (nodep)
  		err |= put_user(cpu_to_node(cpu), nodep);
  	if (cache) {
  		/*
  		 * The cache is not needed for this implementation,
  		 * but make sure user programs pass something
  		 * valid. vsyscall implementations can instead make
  		 * good use of the cache. Only use t0 and t1 because
  		 * these are available in both 32bit and 64bit ABI (no
  		 * need for a compat_getcpu). 32bit has enough
  		 * padding
  		 */
  		unsigned long t0, t1;

  		get_user(t0, &cache->blob[0]);
  		get_user(t1, &cache->blob[1]);

  		t0++;
  		t1++;

  		put_user(t0, &cache->blob[0]);
  		put_user(t1, &cache->blob[1]);

  	}
  	return err ? -EFAULT : 0;
  }