ydb/contrib/libs/libaio/io_getevents.c

/* io_getevents.c 
   libaio Linux async I/O interface 
   Copyright 2002 Red Hat, Inc. 
 
   This library is free software; you can redistribute it and/or 
   modify it under the terms of the GNU Lesser General Public 
   License as published by the Free Software Foundation; either 
   version 2 of the License, or (at your option) any later version. 
 
   This library is distributed in the hope that it will be useful, 
   but WITHOUT ANY WARRANTY; without even the implied warranty of 
   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU 
   Lesser General Public License for more details. 
 
   You should have received a copy of the GNU Lesser General Public 
   License along with this library; if not, write to the Free Software 
   Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307  USA 
 */ 
#include "libaio.h" 
#include <errno.h> 
#include <stdlib.h> 
#include <time.h> 
#include "syscall.h" 
 
io_syscall5(int, __io_getevents_0_4, io_getevents, io_context_t, ctx, long, min_nr, long, nr, struct io_event *, events, struct timespec *, timeout) 
 
#define AIO_RING_MAGIC                  0xa10a10a1 
 
/* Ben will hate me for this */ 
struct aio_ring { 
	unsigned        id;     /* kernel internal index number */ 
	unsigned        nr;     /* number of io_events */ 
	unsigned        head; 
	unsigned        tail; 
 
	unsigned        magic; 
	unsigned        compat_features; 
	unsigned        incompat_features; 
	unsigned        header_length;  /* size of aio_ring */ 
}; 
 

int io_getevents(io_context_t ctx, long min_nr, long nr, struct io_event * events, struct timespec * timeout)
{ 
	struct aio_ring *ring; 
	ring = (struct aio_ring*)ctx; 
	if (ring==NULL || ring->magic != AIO_RING_MAGIC) 
		goto do_syscall; 
	if (timeout!=NULL && timeout->tv_sec == 0 && timeout->tv_nsec == 0) { 
		if (ring->head == ring->tail) 
			return 0; 
	} 
 
do_syscall: 
	return __io_getevents_0_4(ctx, min_nr, nr, events, timeout); 
}