/*
   * This file contains the procedures for the handling of select and poll
   *
   * Created for Linux based loosely upon Mathius Lattner's minix
   * patches by Peter MacDonald. Heavily edited by Linus.
   *
   *  4 February 1994
   *     COFF/ELF binary emulation. If the process has the STICKY_TIMEOUTS
   *     flag set in its personality we do *not* modify the given timeout
   *     parameter to reflect time remaining.
   *
   *  24 January 2000
   *     Changed sys_poll()/do_poll() to use PAGE_SIZE chunk-based allocation 
   *     of fds to overcome nfds < 16390 descriptors limit (Tigran Aivazian).
   */

  #include <linux/kernel.h>

  #include <linux/syscalls.h>
  #include <linux/module.h>
  #include <linux/slab.h>

  #include <linux/poll.h>
  #include <linux/personality.h> /* for STICKY_TIMEOUTS */
  #include <linux/file.h>
  #include <linux/fs.h>

  #include <linux/rcupdate.h>

  
  #include <asm/uaccess.h>

  struct poll_table_page {
  	struct poll_table_page * next;
  	struct poll_table_entry * entry;
  	struct poll_table_entry entries[0];
  };
  
  #define POLL_TABLE_FULL(table) \
  	((unsigned long)((table)->entry+1) > PAGE_SIZE + (unsigned long)(table))
  
  /*
   * Ok, Peter made a complicated, but straightforward multiple_wait() function.
   * I have rewritten this, taking some shortcuts: This code may not be easy to
   * follow, but it should be free of race-conditions, and it's practical. If you
   * understand what I'm doing here, then you understand how the linux
   * sleep/wakeup mechanism works.
   *
   * Two very simple procedures, poll_wait() and poll_freewait() make all the
   * work.  poll_wait() is an inline-function defined in <linux/poll.h>,
   * as all select/poll functions have to call it to add an entry to the
   * poll table.
   */

  static void __pollwait(struct file *filp, wait_queue_head_t *wait_address,
  		       poll_table *p);

  
  void poll_initwait(struct poll_wqueues *pwq)
  {
  	init_poll_funcptr(&pwq->pt, __pollwait);
  	pwq->error = 0;
  	pwq->table = NULL;

  	pwq->inline_index = 0;

  }
  
  EXPORT_SYMBOL(poll_initwait);

  static void free_poll_entry(struct poll_table_entry *entry)
  {

  	remove_wait_queue(entry->wait_address, &entry->wait);

  	fput(entry->filp);
  }

  void poll_freewait(struct poll_wqueues *pwq)
  {
  	struct poll_table_page * p = pwq->table;

  	int i;
  	for (i = 0; i < pwq->inline_index; i++)
  		free_poll_entry(pwq->inline_entries + i);

  	while (p) {
  		struct poll_table_entry * entry;
  		struct poll_table_page *old;
  
  		entry = p->entry;
  		do {
  			entry--;

  			free_poll_entry(entry);

  		} while (entry > p->entries);
  		old = p;
  		p = p->next;
  		free_page((unsigned long) old);
  	}
  }
  
  EXPORT_SYMBOL(poll_freewait);

  static struct poll_table_entry *poll_get_entry(poll_table *_p)

  {
  	struct poll_wqueues *p = container_of(_p, struct poll_wqueues, pt);
  	struct poll_table_page *table = p->table;

  	if (p->inline_index < N_INLINE_POLL_ENTRIES)
  		return p->inline_entries + p->inline_index++;

  	if (!table || POLL_TABLE_FULL(table)) {
  		struct poll_table_page *new_table;
  
  		new_table = (struct poll_table_page *) __get_free_page(GFP_KERNEL);
  		if (!new_table) {
  			p->error = -ENOMEM;
  			__set_current_state(TASK_RUNNING);

  			return NULL;

  		}
  		new_table->entry = new_table->entries;
  		new_table->next = table;
  		p->table = new_table;
  		table = new_table;
  	}

  	return table->entry++;
  }
  
  /* Add a new entry */
  static void __pollwait(struct file *filp, wait_queue_head_t *wait_address,
  				poll_table *p)
  {
  	struct poll_table_entry *entry = poll_get_entry(p);
  	if (!entry)
  		return;
  	get_file(filp);
  	entry->filp = filp;
  	entry->wait_address = wait_address;
  	init_waitqueue_entry(&entry->wait, current);

  	add_wait_queue(wait_address, &entry->wait);

  }
  
  #define FDS_IN(fds, n)		(fds->in + n)
  #define FDS_OUT(fds, n)		(fds->out + n)
  #define FDS_EX(fds, n)		(fds->ex + n)
  
  #define BITS(fds, n)	(*FDS_IN(fds, n)|*FDS_OUT(fds, n)|*FDS_EX(fds, n))
  
  static int max_select_fd(unsigned long n, fd_set_bits *fds)
  {
  	unsigned long *open_fds;
  	unsigned long set;
  	int max;

  	struct fdtable *fdt;

  
  	/* handle last in-complete long-word first */
  	set = ~(~0UL << (n & (__NFDBITS-1)));
  	n /= __NFDBITS;

  	fdt = files_fdtable(current->files);
  	open_fds = fdt->open_fds->fds_bits+n;

  	max = 0;
  	if (set) {
  		set &= BITS(fds, n);
  		if (set) {
  			if (!(set & ~*open_fds))
  				goto get_max;
  			return -EBADF;
  		}
  	}
  	while (n) {
  		open_fds--;
  		n--;
  		set = BITS(fds, n);
  		if (!set)
  			continue;
  		if (set & ~*open_fds)
  			return -EBADF;
  		if (max)
  			continue;
  get_max:
  		do {
  			max++;
  			set >>= 1;
  		} while (set);
  		max += n * __NFDBITS;
  	}
  
  	return max;
  }

  #define POLLIN_SET (POLLRDNORM | POLLRDBAND | POLLIN | POLLHUP | POLLERR)
  #define POLLOUT_SET (POLLWRBAND | POLLWRNORM | POLLOUT | POLLERR)
  #define POLLEX_SET (POLLPRI)

  int do_select(int n, fd_set_bits *fds, s64 *timeout)

  {
  	struct poll_wqueues table;
  	poll_table *wait;
  	int retval, i;

  	rcu_read_lock();

  	retval = max_select_fd(n, fds);

  	rcu_read_unlock();

  
  	if (retval < 0)
  		return retval;
  	n = retval;
  
  	poll_initwait(&table);
  	wait = &table.pt;

  	if (!*timeout)

  		wait = NULL;
  	retval = 0;
  	for (;;) {
  		unsigned long *rinp, *routp, *rexp, *inp, *outp, *exp;

  		long __timeout;

  
  		set_current_state(TASK_INTERRUPTIBLE);
  
  		inp = fds->in; outp = fds->out; exp = fds->ex;
  		rinp = fds->res_in; routp = fds->res_out; rexp = fds->res_ex;
  
  		for (i = 0; i < n; ++rinp, ++routp, ++rexp) {
  			unsigned long in, out, ex, all_bits, bit = 1, mask, j;
  			unsigned long res_in = 0, res_out = 0, res_ex = 0;

  			const struct file_operations *f_op = NULL;

  			struct file *file = NULL;
  
  			in = *inp++; out = *outp++; ex = *exp++;
  			all_bits = in | out | ex;
  			if (all_bits == 0) {
  				i += __NFDBITS;
  				continue;
  			}
  
  			for (j = 0; j < __NFDBITS; ++j, ++i, bit <<= 1) {

  				int fput_needed;

  				if (i >= n)
  					break;
  				if (!(bit & all_bits))
  					continue;

  				file = fget_light(i, &fput_needed);

  				if (file) {
  					f_op = file->f_op;
  					mask = DEFAULT_POLLMASK;
  					if (f_op && f_op->poll)
  						mask = (*f_op->poll)(file, retval ? NULL : wait);

  					fput_light(file, fput_needed);

  					if ((mask & POLLIN_SET) && (in & bit)) {
  						res_in |= bit;
  						retval++;
  					}
  					if ((mask & POLLOUT_SET) && (out & bit)) {
  						res_out |= bit;
  						retval++;
  					}
  					if ((mask & POLLEX_SET) && (ex & bit)) {
  						res_ex |= bit;
  						retval++;
  					}
  				}
  				cond_resched();
  			}
  			if (res_in)
  				*rinp = res_in;
  			if (res_out)
  				*routp = res_out;
  			if (res_ex)
  				*rexp = res_ex;
  		}
  		wait = NULL;

  		if (retval || !*timeout || signal_pending(current))

  			break;
  		if(table.error) {
  			retval = table.error;
  			break;
  		}

  
  		if (*timeout < 0) {
  			/* Wait indefinitely */
  			__timeout = MAX_SCHEDULE_TIMEOUT;
  		} else if (unlikely(*timeout >= (s64)MAX_SCHEDULE_TIMEOUT - 1)) {
  			/* Wait for longer than MAX_SCHEDULE_TIMEOUT. Do it in a loop */
  			__timeout = MAX_SCHEDULE_TIMEOUT - 1;
  			*timeout -= __timeout;
  		} else {
  			__timeout = *timeout;
  			*timeout = 0;
  		}

  		__timeout = schedule_timeout(__timeout);

  		if (*timeout >= 0)
  			*timeout += __timeout;

  	}
  	__set_current_state(TASK_RUNNING);
  
  	poll_freewait(&table);

  	return retval;
  }

  /*
   * We can actually return ERESTARTSYS instead of EINTR, but I'd
   * like to be certain this leads to no problems. So I return
   * EINTR just for safety.
   *
   * Update: ERESTARTSYS breaks at least the xview clock binary, so
   * I'm trying ERESTARTNOHAND which restart only when you want to.
   */
  #define MAX_SELECT_SECONDS \
  	((unsigned long) (MAX_SCHEDULE_TIMEOUT / HZ)-1)

  static int core_sys_select(int n, fd_set __user *inp, fd_set __user *outp,
  			   fd_set __user *exp, s64 *timeout)

  {
  	fd_set_bits fds;

  	void *bits;

  	int ret, max_fds;

  	unsigned int size;

  	struct fdtable *fdt;

  	/* Allocate small arguments on the stack to save memory and be faster */

  	long stack_fds[SELECT_STACK_ALLOC/sizeof(long)];

  	ret = -EINVAL;
  	if (n < 0)
  		goto out_nofds;

  	/* max_fds can increase, so grab it once to avoid race */

  	rcu_read_lock();

  	fdt = files_fdtable(current->files);

  	max_fds = fdt->max_fds;

  	rcu_read_unlock();

  	if (n > max_fds)
  		n = max_fds;

  
  	/*
  	 * We need 6 bitmaps (in/out/ex for both incoming and outgoing),
  	 * since we used fdset we need to allocate memory in units of
  	 * long-words. 
  	 */

  	size = FDS_BYTES(n);

  	bits = stack_fds;
  	if (size > sizeof(stack_fds) / 6) {
  		/* Not enough space in on-stack array; must use kmalloc */
  		ret = -ENOMEM;

  		bits = kmalloc(6 * size, GFP_KERNEL);

  		if (!bits)
  			goto out_nofds;
  	}

  	fds.in      = bits;
  	fds.out     = bits +   size;
  	fds.ex      = bits + 2*size;
  	fds.res_in  = bits + 3*size;
  	fds.res_out = bits + 4*size;
  	fds.res_ex  = bits + 5*size;

  
  	if ((ret = get_fd_set(n, inp, fds.in)) ||
  	    (ret = get_fd_set(n, outp, fds.out)) ||
  	    (ret = get_fd_set(n, exp, fds.ex)))
  		goto out;
  	zero_fd_set(n, fds.res_in);
  	zero_fd_set(n, fds.res_out);
  	zero_fd_set(n, fds.res_ex);

  	ret = do_select(n, &fds, timeout);

  
  	if (ret < 0)
  		goto out;
  	if (!ret) {
  		ret = -ERESTARTNOHAND;
  		if (signal_pending(current))
  			goto out;
  		ret = 0;
  	}
  
  	if (set_fd_set(n, inp, fds.res_in) ||
  	    set_fd_set(n, outp, fds.res_out) ||
  	    set_fd_set(n, exp, fds.res_ex))
  		ret = -EFAULT;
  
  out:

  	if (bits != stack_fds)
  		kfree(bits);

  out_nofds:
  	return ret;
  }

  asmlinkage long sys_select(int n, fd_set __user *inp, fd_set __user *outp,
  			fd_set __user *exp, struct timeval __user *tvp)
  {
  	s64 timeout = -1;
  	struct timeval tv;
  	int ret;
  
  	if (tvp) {
  		if (copy_from_user(&tv, tvp, sizeof(tv)))
  			return -EFAULT;
  
  		if (tv.tv_sec < 0 || tv.tv_usec < 0)
  			return -EINVAL;
  
  		/* Cast to u64 to make GCC stop complaining */
  		if ((u64)tv.tv_sec >= (u64)MAX_INT64_SECONDS)
  			timeout = -1;	/* infinite */
  		else {

  			timeout = DIV_ROUND_UP(tv.tv_usec, USEC_PER_SEC/HZ);

  			timeout += tv.tv_sec * HZ;
  		}
  	}
  
  	ret = core_sys_select(n, inp, outp, exp, &timeout);
  
  	if (tvp) {

  		struct timeval rtv;

  		if (current->personality & STICKY_TIMEOUTS)
  			goto sticky;

  		rtv.tv_usec = jiffies_to_usecs(do_div((*(u64*)&timeout), HZ));
  		rtv.tv_sec = timeout;

  		if (timeval_compare(&rtv, &tv) >= 0)

  			rtv = tv;
  		if (copy_to_user(tvp, &rtv, sizeof(rtv))) {

  sticky:
  			/*
  			 * If an application puts its timeval in read-only
  			 * memory, we don't want the Linux-specific update to
  			 * the timeval to cause a fault after the select has
  			 * completed successfully. However, because we're not
  			 * updating the timeval, we can't restart the system
  			 * call.
  			 */
  			if (ret == -ERESTARTNOHAND)
  				ret = -EINTR;
  		}
  	}
  
  	return ret;
  }
  
  #ifdef TIF_RESTORE_SIGMASK
  asmlinkage long sys_pselect7(int n, fd_set __user *inp, fd_set __user *outp,
  		fd_set __user *exp, struct timespec __user *tsp,
  		const sigset_t __user *sigmask, size_t sigsetsize)
  {
  	s64 timeout = MAX_SCHEDULE_TIMEOUT;
  	sigset_t ksigmask, sigsaved;
  	struct timespec ts;
  	int ret;
  
  	if (tsp) {
  		if (copy_from_user(&ts, tsp, sizeof(ts)))
  			return -EFAULT;
  
  		if (ts.tv_sec < 0 || ts.tv_nsec < 0)
  			return -EINVAL;
  
  		/* Cast to u64 to make GCC stop complaining */
  		if ((u64)ts.tv_sec >= (u64)MAX_INT64_SECONDS)
  			timeout = -1;	/* infinite */
  		else {

  			timeout = DIV_ROUND_UP(ts.tv_nsec, NSEC_PER_SEC/HZ);

  			timeout += ts.tv_sec * HZ;
  		}
  	}
  
  	if (sigmask) {
  		/* XXX: Don't preclude handling different sized sigset_t's.  */
  		if (sigsetsize != sizeof(sigset_t))
  			return -EINVAL;
  		if (copy_from_user(&ksigmask, sigmask, sizeof(ksigmask)))
  			return -EFAULT;
  
  		sigdelsetmask(&ksigmask, sigmask(SIGKILL)|sigmask(SIGSTOP));
  		sigprocmask(SIG_SETMASK, &ksigmask, &sigsaved);
  	}
  
  	ret = core_sys_select(n, inp, outp, exp, &timeout);
  
  	if (tsp) {

  		struct timespec rts;

  		if (current->personality & STICKY_TIMEOUTS)
  			goto sticky;

  		rts.tv_nsec = jiffies_to_usecs(do_div((*(u64*)&timeout), HZ)) *
  						1000;
  		rts.tv_sec = timeout;

  		if (timespec_compare(&rts, &ts) >= 0)

  			rts = ts;
  		if (copy_to_user(tsp, &rts, sizeof(rts))) {

  sticky:
  			/*
  			 * If an application puts its timeval in read-only
  			 * memory, we don't want the Linux-specific update to
  			 * the timeval to cause a fault after the select has
  			 * completed successfully. However, because we're not
  			 * updating the timeval, we can't restart the system
  			 * call.
  			 */
  			if (ret == -ERESTARTNOHAND)
  				ret = -EINTR;
  		}
  	}
  
  	if (ret == -ERESTARTNOHAND) {
  		/*
  		 * Don't restore the signal mask yet. Let do_signal() deliver
  		 * the signal on the way back to userspace, before the signal
  		 * mask is restored.
  		 */
  		if (sigmask) {
  			memcpy(&current->saved_sigmask, &sigsaved,
  					sizeof(sigsaved));
  			set_thread_flag(TIF_RESTORE_SIGMASK);
  		}
  	} else if (sigmask)
  		sigprocmask(SIG_SETMASK, &sigsaved, NULL);
  
  	return ret;
  }
  
  /*
   * Most architectures can't handle 7-argument syscalls. So we provide a
   * 6-argument version where the sixth argument is a pointer to a structure
   * which has a pointer to the sigset_t itself followed by a size_t containing
   * the sigset size.
   */
  asmlinkage long sys_pselect6(int n, fd_set __user *inp, fd_set __user *outp,
  	fd_set __user *exp, struct timespec __user *tsp, void __user *sig)
  {
  	size_t sigsetsize = 0;
  	sigset_t __user *up = NULL;
  
  	if (sig) {
  		if (!access_ok(VERIFY_READ, sig, sizeof(void *)+sizeof(size_t))

  		    || __get_user(up, (sigset_t __user * __user *)sig)

  		    || __get_user(sigsetsize,

  				(size_t __user *)(sig+sizeof(void *))))

  			return -EFAULT;
  	}
  
  	return sys_pselect7(n, inp, outp, exp, tsp, up, sigsetsize);
  }
  #endif /* TIF_RESTORE_SIGMASK */

  struct poll_list {
  	struct poll_list *next;
  	int len;
  	struct pollfd entries[0];
  };
  
  #define POLLFD_PER_PAGE  ((PAGE_SIZE-sizeof(struct poll_list)) / sizeof(struct pollfd))

  /*
   * Fish for pollable events on the pollfd->fd file descriptor. We're only
   * interested in events matching the pollfd->events mask, and the result
   * matching that mask is both recorded in pollfd->revents and returned. The
   * pwait poll_table will be used by the fd-provided poll handler for waiting,
   * if non-NULL.
   */
  static inline unsigned int do_pollfd(struct pollfd *pollfd, poll_table *pwait)

  {

  	unsigned int mask;
  	int fd;
  
  	mask = 0;
  	fd = pollfd->fd;
  	if (fd >= 0) {
  		int fput_needed;
  		struct file * file;
  
  		file = fget_light(fd, &fput_needed);
  		mask = POLLNVAL;
  		if (file != NULL) {
  			mask = DEFAULT_POLLMASK;
  			if (file->f_op && file->f_op->poll)
  				mask = file->f_op->poll(file, pwait);
  			/* Mask out unneeded events. */
  			mask &= pollfd->events | POLLERR | POLLHUP;
  			fput_light(file, fput_needed);

  		}

  	}

  	pollfd->revents = mask;
  
  	return mask;

  }
  
  static int do_poll(unsigned int nfds,  struct poll_list *list,

  		   struct poll_wqueues *wait, s64 *timeout)

  {
  	int count = 0;
  	poll_table* pt = &wait->pt;

  	/* Optimise the no-wait case */
  	if (!(*timeout))

  		pt = NULL;

  	for (;;) {
  		struct poll_list *walk;

  		long __timeout;

  		set_current_state(TASK_INTERRUPTIBLE);

  		for (walk = list; walk != NULL; walk = walk->next) {
  			struct pollfd * pfd, * pfd_end;
  
  			pfd = walk->entries;
  			pfd_end = pfd + walk->len;
  			for (; pfd != pfd_end; pfd++) {
  				/*
  				 * Fish for events. If we found one, record it
  				 * and kill the poll_table, so we don't
  				 * needlessly register any other waiters after
  				 * this. They'll get immediately deregistered
  				 * when we break out and return.
  				 */
  				if (do_pollfd(pfd, pt)) {
  					count++;
  					pt = NULL;
  				}
  			}

  		}

  		/*
  		 * All waiters have already been registered, so don't provide
  		 * a poll_table to them on the next loop iteration.
  		 */

  		pt = NULL;

  		if (!count) {
  			count = wait->error;
  			if (signal_pending(current))
  				count = -EINTR;
  		}
  		if (count || !*timeout)

  			break;

  
  		if (*timeout < 0) {
  			/* Wait indefinitely */
  			__timeout = MAX_SCHEDULE_TIMEOUT;
  		} else if (unlikely(*timeout >= (s64)MAX_SCHEDULE_TIMEOUT-1)) {
  			/*
  			 * Wait for longer than MAX_SCHEDULE_TIMEOUT. Do it in
  			 * a loop
  			 */
  			__timeout = MAX_SCHEDULE_TIMEOUT - 1;
  			*timeout -= __timeout;
  		} else {
  			__timeout = *timeout;
  			*timeout = 0;
  		}
  
  		__timeout = schedule_timeout(__timeout);
  		if (*timeout >= 0)
  			*timeout += __timeout;

  	}
  	__set_current_state(TASK_RUNNING);
  	return count;
  }

  #define N_STACK_PPS ((sizeof(stack_pps) - sizeof(struct poll_list))  / \
  			sizeof(struct pollfd))

  int do_sys_poll(struct pollfd __user *ufds, unsigned int nfds, s64 *timeout)

  {
  	struct poll_wqueues table;

   	int err = -EFAULT, fdcount, len, size;

  	/* Allocate small arguments on the stack to save memory and be
  	   faster - use long to make sure the buffer is aligned properly
  	   on 64 bit archs to avoid unaligned access */
  	long stack_pps[POLL_STACK_ALLOC/sizeof(long)];

  	struct poll_list *const head = (struct poll_list *)stack_pps;
   	struct poll_list *walk = head;
   	unsigned long todo = nfds;

  	if (nfds > current->signal->rlim[RLIMIT_NOFILE].rlim_cur)

  		return -EINVAL;

  	len = min_t(unsigned int, nfds, N_STACK_PPS);
  	for (;;) {
  		walk->next = NULL;
  		walk->len = len;
  		if (!len)
  			break;

  		if (copy_from_user(walk->entries, ufds + nfds-todo,
  					sizeof(struct pollfd) * walk->len))
  			goto out_fds;
  
  		todo -= walk->len;
  		if (!todo)
  			break;

  		len = min(todo, POLLFD_PER_PAGE);
  		size = sizeof(struct poll_list) + sizeof(struct pollfd) * len;
  		walk = walk->next = kmalloc(size, GFP_KERNEL);
  		if (!walk) {
  			err = -ENOMEM;

  			goto out_fds;
  		}

  	}

  	poll_initwait(&table);

  	fdcount = do_poll(nfds, head, &table, timeout);

  	poll_freewait(&table);

  	for (walk = head; walk; walk = walk->next) {

  		struct pollfd *fds = walk->entries;
  		int j;

  		for (j = 0; j < walk->len; j++, ufds++)
  			if (__put_user(fds[j].revents, &ufds->revents))

  				goto out_fds;

    	}

  	err = fdcount;

  out_fds:

  	walk = head->next;
  	while (walk) {
  		struct poll_list *pos = walk;
  		walk = walk->next;
  		kfree(pos);

  	}

  	return err;
  }

  static long do_restart_poll(struct restart_block *restart_block)
  {
  	struct pollfd __user *ufds = (struct pollfd __user*)restart_block->arg0;
  	int nfds = restart_block->arg1;
  	s64 timeout = ((s64)restart_block->arg3<<32) | (s64)restart_block->arg2;
  	int ret;
  
  	ret = do_sys_poll(ufds, nfds, &timeout);
  	if (ret == -EINTR) {
  		restart_block->fn = do_restart_poll;
  		restart_block->arg2 = timeout & 0xFFFFFFFF;
  		restart_block->arg3 = (u64)timeout >> 32;
  		ret = -ERESTART_RESTARTBLOCK;
  	}
  	return ret;
  }

  asmlinkage long sys_poll(struct pollfd __user *ufds, unsigned int nfds,
  			long timeout_msecs)
  {

  	s64 timeout_jiffies;

  	int ret;

  	if (timeout_msecs > 0) {

  #if HZ > 1000
  		/* We can only overflow if HZ > 1000 */
  		if (timeout_msecs / 1000 > (s64)0x7fffffffffffffffULL / (s64)HZ)
  			timeout_jiffies = -1;
  		else
  #endif

  			timeout_jiffies = msecs_to_jiffies(timeout_msecs) + 1;

  	} else {
  		/* Infinite (< 0) or no (0) timeout */
  		timeout_jiffies = timeout_msecs;

  	}

  	ret = do_sys_poll(ufds, nfds, &timeout_jiffies);
  	if (ret == -EINTR) {
  		struct restart_block *restart_block;
  		restart_block = &current_thread_info()->restart_block;
  		restart_block->fn = do_restart_poll;
  		restart_block->arg0 = (unsigned long)ufds;
  		restart_block->arg1 = nfds;
  		restart_block->arg2 = timeout_jiffies & 0xFFFFFFFF;
  		restart_block->arg3 = (u64)timeout_jiffies >> 32;
  		ret = -ERESTART_RESTARTBLOCK;
  	}
  	return ret;

  }
  
  #ifdef TIF_RESTORE_SIGMASK
  asmlinkage long sys_ppoll(struct pollfd __user *ufds, unsigned int nfds,
  	struct timespec __user *tsp, const sigset_t __user *sigmask,
  	size_t sigsetsize)
  {
  	sigset_t ksigmask, sigsaved;
  	struct timespec ts;
  	s64 timeout = -1;
  	int ret;
  
  	if (tsp) {
  		if (copy_from_user(&ts, tsp, sizeof(ts)))
  			return -EFAULT;
  
  		/* Cast to u64 to make GCC stop complaining */
  		if ((u64)ts.tv_sec >= (u64)MAX_INT64_SECONDS)
  			timeout = -1;	/* infinite */
  		else {

  			timeout = DIV_ROUND_UP(ts.tv_nsec, NSEC_PER_SEC/HZ);

  			timeout += ts.tv_sec * HZ;
  		}
  	}
  
  	if (sigmask) {
  		/* XXX: Don't preclude handling different sized sigset_t's.  */
  		if (sigsetsize != sizeof(sigset_t))
  			return -EINVAL;
  		if (copy_from_user(&ksigmask, sigmask, sizeof(ksigmask)))
  			return -EFAULT;
  
  		sigdelsetmask(&ksigmask, sigmask(SIGKILL)|sigmask(SIGSTOP));
  		sigprocmask(SIG_SETMASK, &ksigmask, &sigsaved);
  	}
  
  	ret = do_sys_poll(ufds, nfds, &timeout);
  
  	/* We can restart this syscall, usually */
  	if (ret == -EINTR) {
  		/*
  		 * Don't restore the signal mask yet. Let do_signal() deliver
  		 * the signal on the way back to userspace, before the signal
  		 * mask is restored.
  		 */
  		if (sigmask) {
  			memcpy(&current->saved_sigmask, &sigsaved,
  					sizeof(sigsaved));
  			set_thread_flag(TIF_RESTORE_SIGMASK);
  		}
  		ret = -ERESTARTNOHAND;
  	} else if (sigmask)
  		sigprocmask(SIG_SETMASK, &sigsaved, NULL);
  
  	if (tsp && timeout >= 0) {

  		struct timespec rts;

  		if (current->personality & STICKY_TIMEOUTS)
  			goto sticky;
  		/* Yes, we know it's actually an s64, but it's also positive. */

  		rts.tv_nsec = jiffies_to_usecs(do_div((*(u64*)&timeout), HZ)) *
  						1000;
  		rts.tv_sec = timeout;

  		if (timespec_compare(&rts, &ts) >= 0)

  			rts = ts;
  		if (copy_to_user(tsp, &rts, sizeof(rts))) {

  		sticky:
  			/*
  			 * If an application puts its timeval in read-only
  			 * memory, we don't want the Linux-specific update to
  			 * the timeval to cause a fault after the select has
  			 * completed successfully. However, because we're not
  			 * updating the timeval, we can't restart the system
  			 * call.
  			 */
  			if (ret == -ERESTARTNOHAND && timeout >= 0)
  				ret = -EINTR;
  		}
  	}
  
  	return ret;
  }
  #endif /* TIF_RESTORE_SIGMASK */