841 lines
		
	
	
		
			20 KiB
		
	
	
	
		
			C
		
	
	
	
			
		
		
	
	
			841 lines
		
	
	
		
			20 KiB
		
	
	
	
		
			C
		
	
	
	
| /*
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|  * This file contains the procedures for the handling of select and poll
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|  *
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|  * Created for Linux based loosely upon Mathius Lattner's minix
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|  * patches by Peter MacDonald. Heavily edited by Linus.
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|  *
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|  *  4 February 1994
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|  *     COFF/ELF binary emulation. If the process has the STICKY_TIMEOUTS
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|  *     flag set in its personality we do *not* modify the given timeout
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|  *     parameter to reflect time remaining.
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|  *
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|  *  24 January 2000
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|  *     Changed sys_poll()/do_poll() to use PAGE_SIZE chunk-based allocation 
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|  *     of fds to overcome nfds < 16390 descriptors limit (Tigran Aivazian).
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|  */
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| 
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| #include <linux/kernel.h>
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| #include <linux/syscalls.h>
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| #include <linux/module.h>
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| #include <linux/slab.h>
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| #include <linux/poll.h>
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| #include <linux/personality.h> /* for STICKY_TIMEOUTS */
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| #include <linux/file.h>
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| #include <linux/fs.h>
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| #include <linux/rcupdate.h>
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| 
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| #include <asm/uaccess.h>
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| 
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| #define DEFAULT_POLLMASK (POLLIN | POLLOUT | POLLRDNORM | POLLWRNORM)
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| 
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| struct poll_table_page {
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| 	struct poll_table_page * next;
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| 	struct poll_table_entry * entry;
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| 	struct poll_table_entry entries[0];
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| };
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| 
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| #define POLL_TABLE_FULL(table) \
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| 	((unsigned long)((table)->entry+1) > PAGE_SIZE + (unsigned long)(table))
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| 
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| /*
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|  * Ok, Peter made a complicated, but straightforward multiple_wait() function.
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|  * I have rewritten this, taking some shortcuts: This code may not be easy to
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|  * follow, but it should be free of race-conditions, and it's practical. If you
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|  * understand what I'm doing here, then you understand how the linux
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|  * sleep/wakeup mechanism works.
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|  *
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|  * Two very simple procedures, poll_wait() and poll_freewait() make all the
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|  * work.  poll_wait() is an inline-function defined in <linux/poll.h>,
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|  * as all select/poll functions have to call it to add an entry to the
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|  * poll table.
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|  */
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| static void __pollwait(struct file *filp, wait_queue_head_t *wait_address,
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| 		       poll_table *p);
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| 
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| void poll_initwait(struct poll_wqueues *pwq)
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| {
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| 	init_poll_funcptr(&pwq->pt, __pollwait);
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| 	pwq->error = 0;
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| 	pwq->table = NULL;
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| 	pwq->inline_index = 0;
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| }
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| 
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| EXPORT_SYMBOL(poll_initwait);
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| 
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| static void free_poll_entry(struct poll_table_entry *entry)
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| {
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| 	remove_wait_queue(entry->wait_address,&entry->wait);
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| 	fput(entry->filp);
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| }
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| 
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| void poll_freewait(struct poll_wqueues *pwq)
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| {
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| 	struct poll_table_page * p = pwq->table;
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| 	int i;
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| 	for (i = 0; i < pwq->inline_index; i++)
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| 		free_poll_entry(pwq->inline_entries + i);
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| 	while (p) {
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| 		struct poll_table_entry * entry;
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| 		struct poll_table_page *old;
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| 
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| 		entry = p->entry;
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| 		do {
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| 			entry--;
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| 			free_poll_entry(entry);
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| 		} while (entry > p->entries);
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| 		old = p;
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| 		p = p->next;
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| 		free_page((unsigned long) old);
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| 	}
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| }
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| 
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| EXPORT_SYMBOL(poll_freewait);
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| 
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| static struct poll_table_entry *poll_get_entry(poll_table *_p)
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| {
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| 	struct poll_wqueues *p = container_of(_p, struct poll_wqueues, pt);
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| 	struct poll_table_page *table = p->table;
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| 
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| 	if (p->inline_index < N_INLINE_POLL_ENTRIES)
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| 		return p->inline_entries + p->inline_index++;
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| 
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| 	if (!table || POLL_TABLE_FULL(table)) {
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| 		struct poll_table_page *new_table;
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| 
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| 		new_table = (struct poll_table_page *) __get_free_page(GFP_KERNEL);
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| 		if (!new_table) {
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| 			p->error = -ENOMEM;
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| 			__set_current_state(TASK_RUNNING);
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| 			return NULL;
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| 		}
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| 		new_table->entry = new_table->entries;
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| 		new_table->next = table;
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| 		p->table = new_table;
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| 		table = new_table;
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| 	}
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| 
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| 	return table->entry++;
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| }
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| 
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| /* Add a new entry */
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| static void __pollwait(struct file *filp, wait_queue_head_t *wait_address,
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| 				poll_table *p)
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| {
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| 	struct poll_table_entry *entry = poll_get_entry(p);
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| 	if (!entry)
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| 		return;
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| 	get_file(filp);
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| 	entry->filp = filp;
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| 	entry->wait_address = wait_address;
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| 	init_waitqueue_entry(&entry->wait, current);
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| 	add_wait_queue(wait_address,&entry->wait);
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| }
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| 
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| #define FDS_IN(fds, n)		(fds->in + n)
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| #define FDS_OUT(fds, n)		(fds->out + n)
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| #define FDS_EX(fds, n)		(fds->ex + n)
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| 
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| #define BITS(fds, n)	(*FDS_IN(fds, n)|*FDS_OUT(fds, n)|*FDS_EX(fds, n))
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| 
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| static int max_select_fd(unsigned long n, fd_set_bits *fds)
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| {
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| 	unsigned long *open_fds;
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| 	unsigned long set;
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| 	int max;
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| 	struct fdtable *fdt;
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| 
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| 	/* handle last in-complete long-word first */
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| 	set = ~(~0UL << (n & (__NFDBITS-1)));
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| 	n /= __NFDBITS;
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| 	fdt = files_fdtable(current->files);
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| 	open_fds = fdt->open_fds->fds_bits+n;
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| 	max = 0;
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| 	if (set) {
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| 		set &= BITS(fds, n);
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| 		if (set) {
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| 			if (!(set & ~*open_fds))
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| 				goto get_max;
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| 			return -EBADF;
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| 		}
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| 	}
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| 	while (n) {
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| 		open_fds--;
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| 		n--;
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| 		set = BITS(fds, n);
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| 		if (!set)
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| 			continue;
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| 		if (set & ~*open_fds)
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| 			return -EBADF;
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| 		if (max)
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| 			continue;
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| get_max:
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| 		do {
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| 			max++;
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| 			set >>= 1;
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| 		} while (set);
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| 		max += n * __NFDBITS;
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| 	}
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| 
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| 	return max;
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| }
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| 
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| #define BIT(i)		(1UL << ((i)&(__NFDBITS-1)))
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| #define MEM(i,m)	((m)+(unsigned)(i)/__NFDBITS)
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| #define ISSET(i,m)	(((i)&*(m)) != 0)
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| #define SET(i,m)	(*(m) |= (i))
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| 
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| #define POLLIN_SET (POLLRDNORM | POLLRDBAND | POLLIN | POLLHUP | POLLERR)
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| #define POLLOUT_SET (POLLWRBAND | POLLWRNORM | POLLOUT | POLLERR)
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| #define POLLEX_SET (POLLPRI)
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| 
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| int do_select(int n, fd_set_bits *fds, s64 *timeout)
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| {
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| 	struct poll_wqueues table;
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| 	poll_table *wait;
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| 	int retval, i;
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| 
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| 	rcu_read_lock();
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| 	retval = max_select_fd(n, fds);
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| 	rcu_read_unlock();
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| 
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| 	if (retval < 0)
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| 		return retval;
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| 	n = retval;
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| 
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| 	poll_initwait(&table);
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| 	wait = &table.pt;
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| 	if (!*timeout)
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| 		wait = NULL;
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| 	retval = 0;
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| 	for (;;) {
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| 		unsigned long *rinp, *routp, *rexp, *inp, *outp, *exp;
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| 		long __timeout;
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| 
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| 		set_current_state(TASK_INTERRUPTIBLE);
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| 
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| 		inp = fds->in; outp = fds->out; exp = fds->ex;
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| 		rinp = fds->res_in; routp = fds->res_out; rexp = fds->res_ex;
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| 
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| 		for (i = 0; i < n; ++rinp, ++routp, ++rexp) {
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| 			unsigned long in, out, ex, all_bits, bit = 1, mask, j;
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| 			unsigned long res_in = 0, res_out = 0, res_ex = 0;
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| 			const struct file_operations *f_op = NULL;
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| 			struct file *file = NULL;
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| 
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| 			in = *inp++; out = *outp++; ex = *exp++;
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| 			all_bits = in | out | ex;
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| 			if (all_bits == 0) {
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| 				i += __NFDBITS;
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| 				continue;
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| 			}
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| 
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| 			for (j = 0; j < __NFDBITS; ++j, ++i, bit <<= 1) {
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| 				int fput_needed;
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| 				if (i >= n)
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| 					break;
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| 				if (!(bit & all_bits))
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| 					continue;
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| 				file = fget_light(i, &fput_needed);
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| 				if (file) {
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| 					f_op = file->f_op;
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| 					mask = DEFAULT_POLLMASK;
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| 					if (f_op && f_op->poll)
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| 						mask = (*f_op->poll)(file, retval ? NULL : wait);
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| 					fput_light(file, fput_needed);
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| 					if ((mask & POLLIN_SET) && (in & bit)) {
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| 						res_in |= bit;
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| 						retval++;
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| 					}
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| 					if ((mask & POLLOUT_SET) && (out & bit)) {
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| 						res_out |= bit;
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| 						retval++;
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| 					}
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| 					if ((mask & POLLEX_SET) && (ex & bit)) {
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| 						res_ex |= bit;
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| 						retval++;
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| 					}
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| 				}
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| 				cond_resched();
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| 			}
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| 			if (res_in)
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| 				*rinp = res_in;
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| 			if (res_out)
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| 				*routp = res_out;
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| 			if (res_ex)
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| 				*rexp = res_ex;
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| 		}
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| 		wait = NULL;
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| 		if (retval || !*timeout || signal_pending(current))
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| 			break;
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| 		if(table.error) {
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| 			retval = table.error;
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| 			break;
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| 		}
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| 
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| 		if (*timeout < 0) {
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| 			/* Wait indefinitely */
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| 			__timeout = MAX_SCHEDULE_TIMEOUT;
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| 		} else if (unlikely(*timeout >= (s64)MAX_SCHEDULE_TIMEOUT - 1)) {
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| 			/* Wait for longer than MAX_SCHEDULE_TIMEOUT. Do it in a loop */
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| 			__timeout = MAX_SCHEDULE_TIMEOUT - 1;
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| 			*timeout -= __timeout;
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| 		} else {
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| 			__timeout = *timeout;
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| 			*timeout = 0;
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| 		}
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| 		__timeout = schedule_timeout(__timeout);
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| 		if (*timeout >= 0)
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| 			*timeout += __timeout;
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| 	}
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| 	__set_current_state(TASK_RUNNING);
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| 
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| 	poll_freewait(&table);
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| 
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| 	return retval;
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| }
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| 
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| /*
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|  * We can actually return ERESTARTSYS instead of EINTR, but I'd
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|  * like to be certain this leads to no problems. So I return
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|  * EINTR just for safety.
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|  *
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|  * Update: ERESTARTSYS breaks at least the xview clock binary, so
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|  * I'm trying ERESTARTNOHAND which restart only when you want to.
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|  */
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| #define MAX_SELECT_SECONDS \
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| 	((unsigned long) (MAX_SCHEDULE_TIMEOUT / HZ)-1)
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| 
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| static int core_sys_select(int n, fd_set __user *inp, fd_set __user *outp,
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| 			   fd_set __user *exp, s64 *timeout)
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| {
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| 	fd_set_bits fds;
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| 	void *bits;
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| 	int ret, max_fds;
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| 	unsigned int size;
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| 	struct fdtable *fdt;
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| 	/* Allocate small arguments on the stack to save memory and be faster */
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| 	long stack_fds[SELECT_STACK_ALLOC/sizeof(long)];
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| 
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| 	ret = -EINVAL;
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| 	if (n < 0)
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| 		goto out_nofds;
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| 
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| 	/* max_fds can increase, so grab it once to avoid race */
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| 	rcu_read_lock();
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| 	fdt = files_fdtable(current->files);
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| 	max_fds = fdt->max_fds;
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| 	rcu_read_unlock();
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| 	if (n > max_fds)
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| 		n = max_fds;
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| 
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| 	/*
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| 	 * We need 6 bitmaps (in/out/ex for both incoming and outgoing),
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| 	 * since we used fdset we need to allocate memory in units of
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| 	 * long-words. 
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| 	 */
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| 	size = FDS_BYTES(n);
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| 	bits = stack_fds;
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| 	if (size > sizeof(stack_fds) / 6) {
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| 		/* Not enough space in on-stack array; must use kmalloc */
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| 		ret = -ENOMEM;
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| 		bits = kmalloc(6 * size, GFP_KERNEL);
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| 		if (!bits)
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| 			goto out_nofds;
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| 	}
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| 	fds.in      = bits;
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| 	fds.out     = bits +   size;
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| 	fds.ex      = bits + 2*size;
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| 	fds.res_in  = bits + 3*size;
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| 	fds.res_out = bits + 4*size;
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| 	fds.res_ex  = bits + 5*size;
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| 
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| 	if ((ret = get_fd_set(n, inp, fds.in)) ||
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| 	    (ret = get_fd_set(n, outp, fds.out)) ||
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| 	    (ret = get_fd_set(n, exp, fds.ex)))
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| 		goto out;
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| 	zero_fd_set(n, fds.res_in);
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| 	zero_fd_set(n, fds.res_out);
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| 	zero_fd_set(n, fds.res_ex);
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| 
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| 	ret = do_select(n, &fds, timeout);
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| 
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| 	if (ret < 0)
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| 		goto out;
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| 	if (!ret) {
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| 		ret = -ERESTARTNOHAND;
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| 		if (signal_pending(current))
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| 			goto out;
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| 		ret = 0;
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| 	}
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| 
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| 	if (set_fd_set(n, inp, fds.res_in) ||
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| 	    set_fd_set(n, outp, fds.res_out) ||
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| 	    set_fd_set(n, exp, fds.res_ex))
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| 		ret = -EFAULT;
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| 
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| out:
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| 	if (bits != stack_fds)
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| 		kfree(bits);
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| out_nofds:
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| 	return ret;
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| }
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| 
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| asmlinkage long sys_select(int n, fd_set __user *inp, fd_set __user *outp,
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| 			fd_set __user *exp, struct timeval __user *tvp)
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| {
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| 	s64 timeout = -1;
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| 	struct timeval tv;
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| 	int ret;
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| 
 | |
| 	if (tvp) {
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| 		if (copy_from_user(&tv, tvp, sizeof(tv)))
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| 			return -EFAULT;
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| 
 | |
| 		if (tv.tv_sec < 0 || tv.tv_usec < 0)
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| 			return -EINVAL;
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| 
 | |
| 		/* Cast to u64 to make GCC stop complaining */
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| 		if ((u64)tv.tv_sec >= (u64)MAX_INT64_SECONDS)
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| 			timeout = -1;	/* infinite */
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| 		else {
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| 			timeout = DIV_ROUND_UP(tv.tv_usec, USEC_PER_SEC/HZ);
 | |
| 			timeout += tv.tv_sec * HZ;
 | |
| 		}
 | |
| 	}
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| 
 | |
| 	ret = core_sys_select(n, inp, outp, exp, &timeout);
 | |
| 
 | |
| 	if (tvp) {
 | |
| 		struct timeval rtv;
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| 
 | |
| 		if (current->personality & STICKY_TIMEOUTS)
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| 			goto sticky;
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| 		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))) {
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| sticky:
 | |
| 			/*
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| 			 * If an application puts its timeval in read-only
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| 			 * memory, we don't want the Linux-specific update to
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| 			 * the timeval to cause a fault after the select has
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| 			 * completed successfully. However, because we're not
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| 			 * updating the timeval, we can't restart the system
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| 			 * call.
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| 			 */
 | |
| 			if (ret == -ERESTARTNOHAND)
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| 				ret = -EINTR;
 | |
| 		}
 | |
| 	}
 | |
| 
 | |
| 	return ret;
 | |
| }
 | |
| 
 | |
| #ifdef TIF_RESTORE_SIGMASK
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| asmlinkage long sys_pselect7(int n, fd_set __user *inp, fd_set __user *outp,
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| 		fd_set __user *exp, struct timespec __user *tsp,
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| 		const sigset_t __user *sigmask, size_t sigsetsize)
 | |
| {
 | |
| 	s64 timeout = MAX_SCHEDULE_TIMEOUT;
 | |
| 	sigset_t ksigmask, sigsaved;
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| 	struct timespec ts;
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| 	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)) *
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| 						1000;
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| 		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(¤t->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 || !*timeout || signal_pending(current))
 | |
| 			break;
 | |
| 		count = wait->error;
 | |
| 		if (count)
 | |
| 			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 fdcount, err;
 | |
|  	unsigned int i;
 | |
| 	struct poll_list *head;
 | |
|  	struct poll_list *walk;
 | |
| 	/* 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 *stack_pp = NULL;
 | |
| 
 | |
| 	/* Do a sanity check on nfds ... */
 | |
| 	if (nfds > current->signal->rlim[RLIMIT_NOFILE].rlim_cur)
 | |
| 		return -EINVAL;
 | |
| 
 | |
| 	poll_initwait(&table);
 | |
| 
 | |
| 	head = NULL;
 | |
| 	walk = NULL;
 | |
| 	i = nfds;
 | |
| 	err = -ENOMEM;
 | |
| 	while(i!=0) {
 | |
| 		struct poll_list *pp;
 | |
| 		int num, size;
 | |
| 		if (stack_pp == NULL)
 | |
| 			num = N_STACK_PPS;
 | |
| 		else
 | |
| 			num = POLLFD_PER_PAGE;
 | |
| 		if (num > i)
 | |
| 			num = i;
 | |
| 		size = sizeof(struct poll_list) + sizeof(struct pollfd)*num;
 | |
| 		if (!stack_pp)
 | |
| 			stack_pp = pp = (struct poll_list *)stack_pps;
 | |
| 		else {
 | |
| 			pp = kmalloc(size, GFP_KERNEL);
 | |
| 			if (!pp)
 | |
| 				goto out_fds;
 | |
| 		}
 | |
| 		pp->next=NULL;
 | |
| 		pp->len = num;
 | |
| 		if (head == NULL)
 | |
| 			head = pp;
 | |
| 		else
 | |
| 			walk->next = pp;
 | |
| 
 | |
| 		walk = pp;
 | |
| 		if (copy_from_user(pp->entries, ufds + nfds-i, 
 | |
| 				sizeof(struct pollfd)*num)) {
 | |
| 			err = -EFAULT;
 | |
| 			goto out_fds;
 | |
| 		}
 | |
| 		i -= pp->len;
 | |
| 	}
 | |
| 
 | |
| 	fdcount = do_poll(nfds, head, &table, timeout);
 | |
| 
 | |
| 	/* OK, now copy the revents fields back to user space. */
 | |
| 	walk = head;
 | |
| 	err = -EFAULT;
 | |
| 	while(walk != NULL) {
 | |
| 		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;
 | |
| 		}
 | |
| 		walk = walk->next;
 | |
|   	}
 | |
| 	err = fdcount;
 | |
| 	if (!fdcount && signal_pending(current))
 | |
| 		err = -EINTR;
 | |
| out_fds:
 | |
| 	walk = head;
 | |
| 	while(walk!=NULL) {
 | |
| 		struct poll_list *pp = walk->next;
 | |
| 		if (walk != stack_pp)
 | |
| 			kfree(walk);
 | |
| 		walk = pp;
 | |
| 	}
 | |
| 	poll_freewait(&table);
 | |
| 	return err;
 | |
| }
 | |
| 
 | |
| asmlinkage long sys_poll(struct pollfd __user *ufds, unsigned int nfds,
 | |
| 			long timeout_msecs)
 | |
| {
 | |
| 	s64 timeout_jiffies;
 | |
| 
 | |
| 	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);
 | |
| 	} else {
 | |
| 		/* Infinite (< 0) or no (0) timeout */
 | |
| 		timeout_jiffies = timeout_msecs;
 | |
| 	}
 | |
| 
 | |
| 	return do_sys_poll(ufds, nfds, &timeout_jiffies);
 | |
| }
 | |
| 
 | |
| #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(¤t->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 */
 |