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Filename : eventpoll.h
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/* SPDX-License-Identifier: GPL-2.0+ WITH Linux-syscall-note */
/*
 *  include/linux/eventpoll.h ( Efficient event polling implementation )
 *  Copyright (C) 2001,...,2006	 Davide Libenzi
 *
 *  This program is free software; you can redistribute it and/or modify
 *  it under the terms of the GNU General Public License as published by
 *  the Free Software Foundation; either version 2 of the License, or
 *  (at your option) any later version.
 *
 *  Davide Libenzi <davidel@xmailserver.org>
 *
 */

#ifndef _LINUX_EVENTPOLL_H
#define _LINUX_EVENTPOLL_H

/* For O_CLOEXEC */
#include <linux/fcntl.h>
#include <linux/types.h>

/* Flags for epoll_create1.  */
#define EPOLL_CLOEXEC O_CLOEXEC

/* Valid opcodes to issue to sys_epoll_ctl() */
#define EPOLL_CTL_ADD 1
#define EPOLL_CTL_DEL 2
#define EPOLL_CTL_MOD 3

/* Epoll event masks */
#define EPOLLIN		(__poll_t)0x00000001
#define EPOLLPRI	(__poll_t)0x00000002
#define EPOLLOUT	(__poll_t)0x00000004
#define EPOLLERR	(__poll_t)0x00000008
#define EPOLLHUP	(__poll_t)0x00000010
#define EPOLLNVAL	(__poll_t)0x00000020
#define EPOLLRDNORM	(__poll_t)0x00000040
#define EPOLLRDBAND	(__poll_t)0x00000080
#define EPOLLWRNORM	(__poll_t)0x00000100
#define EPOLLWRBAND	(__poll_t)0x00000200
#define EPOLLMSG	(__poll_t)0x00000400
#define EPOLLRDHUP	(__poll_t)0x00002000

/*
 * Internal flag - wakeup generated by io_uring, used to detect recursion back
 * into the io_uring poll handler.
 */
#define EPOLL_URING_WAKE	((__poll_t)(1U << 27))

/* Set exclusive wakeup mode for the target file descriptor */
#define EPOLLEXCLUSIVE	((__poll_t)(1U << 28))

/*
 * Request the handling of system wakeup events so as to prevent system suspends
 * from happening while those events are being processed.
 *
 * Assuming neither EPOLLET nor EPOLLONESHOT is set, system suspends will not be
 * re-allowed until epoll_wait is called again after consuming the wakeup
 * event(s).
 *
 * Requires CAP_BLOCK_SUSPEND
 */
#define EPOLLWAKEUP	((__poll_t)(1U << 29))

/* Set the One Shot behaviour for the target file descriptor */
#define EPOLLONESHOT	((__poll_t)(1U << 30))

/* Set the Edge Triggered behaviour for the target file descriptor */
#define EPOLLET		((__poll_t)(1U << 31))

/* 
 * On x86-64 make the 64bit structure have the same alignment as the
 * 32bit structure. This makes 32bit emulation easier.
 *
 * UML/x86_64 needs the same packing as x86_64
 */
#ifdef __x86_64__
#define EPOLL_PACKED __attribute__((packed))
#else
#define EPOLL_PACKED
#endif

struct epoll_event {
	__poll_t events;
	__u64 data;
} EPOLL_PACKED;

#ifdef CONFIG_PM_SLEEP
static __inline__ void ep_take_care_of_epollwakeup(struct epoll_event *epev)
{
	if ((epev->events & EPOLLWAKEUP) && !capable(CAP_BLOCK_SUSPEND))
		epev->events &= ~EPOLLWAKEUP;
}
#else
static __inline__ void ep_take_care_of_epollwakeup(struct epoll_event *epev)
{
	epev->events &= ~EPOLLWAKEUP;
}
#endif
#endif /* _LINUX_EVENTPOLL_H */