[lttng-tools.git] / src / common / compat / poll.hpp

/*
 * Copyright (C) 2011 EfficiOS Inc.
 *
 * SPDX-License-Identifier: LGPL-2.1-only
 *
 */

#ifndef _LTT_POLL_H
#define _LTT_POLL_H

#include <common/common.hpp>

#include <string.h>
#include <unistd.h>

/*
 * Used by lttng_poll_clean to free the events structure in a lttng_poll_event.
 */
static inline void __lttng_poll_free(void *events)
{
	free(events);
}

/*
 * epoll(7) implementation.
 */
#ifdef HAVE_EPOLL
#include <common/compat/fcntl.hpp>

#include <features.h>
#include <stdio.h>
#include <sys/epoll.h>

/* See man epoll(7) for this define path */
#define COMPAT_EPOLL_PROC_PATH "/proc/sys/fs/epoll/max_user_watches"

enum {
	/* Polling variables compatibility for epoll */
	LPOLLIN = EPOLLIN,
	LPOLLPRI = EPOLLPRI,
	LPOLLOUT = EPOLLOUT,
	LPOLLRDNORM = EPOLLRDNORM,
	LPOLLRDBAND = EPOLLRDBAND,
	LPOLLWRNORM = EPOLLWRNORM,
	LPOLLWRBAND = EPOLLWRBAND,
	LPOLLMSG = EPOLLMSG,
	LPOLLERR = EPOLLERR,
	LPOLLHUP = EPOLLHUP,
	LPOLLNVAL = EPOLLHUP,
	LPOLLRDHUP = EPOLLRDHUP,
/* Close on exec feature of epoll */
#if defined(HAVE_EPOLL_CREATE1) && defined(EPOLL_CLOEXEC)
	LTTNG_CLOEXEC = EPOLL_CLOEXEC,
#else
	/*
	 * EPOLL_CLOEXEC was added in glibc 2.8 (usually used in conjunction with
	 * epoll_create1(..)), but since neither EPOLL_CLOEXEC exists nor
	 * epoll_create1(..), we set it to FD_CLOEXEC so that we can pass it
	 * directly to fcntl(..) instead.
	 */
	LTTNG_CLOEXEC = FD_CLOEXEC,
#endif
};

struct compat_epoll_event {
	int epfd;
	uint32_t nb_fd; /* Current number of fd in events */
	uint32_t alloc_size; /* Size of events array */
	uint32_t init_size; /* Initial size of events array */
	struct epoll_event *events;
};
#define lttng_poll_event compat_epoll_event

static inline int
__lttng_epoll_get_prev_fd(struct lttng_poll_event *events, int index, uint32_t nb_fd)
{
	LTTNG_ASSERT(events);
	LTTNG_ASSERT(index != nb_fd);

	if (index == 0 || nb_fd == 0) {
		return -1;
	} else {
		return events->events[index - 1].data.fd;
	}
}

/*
 * For the following calls, consider 'e' to be a lttng_poll_event pointer and i
 * being the index of the events array.
 */
#define LTTNG_POLL_GETFD(e, i)		    LTTNG_REF(e)->events[i].data.fd
#define LTTNG_POLL_GETEV(e, i)		    LTTNG_REF(e)->events[i].events
#define LTTNG_POLL_GETNB(e)		    LTTNG_REF(e)->nb_fd
#define LTTNG_POLL_GETSZ(e)		    LTTNG_REF(e)->events_size
#define LTTNG_POLL_GET_PREV_FD(e, i, nb_fd) __lttng_epoll_get_prev_fd(LTTNG_REF(e), i, nb_fd)

/* Create the epoll set. */
extern int compat_epoll_create(struct lttng_poll_event *events, int size, int flags);
#define lttng_poll_create(events, size, flags) compat_epoll_create(events, size, flags)

#if defined(HAVE_EPOLL_CREATE1) && defined(EPOLL_CLOEXEC)
static inline int compat_glibc_epoll_create(int size __attribute__((unused)), int flags)
{
	return epoll_create1(flags);
}
#else
static inline int compat_glibc_epoll_create(int size, int flags)
{
	/*
	 * epoll_create1 was added in glibc 2.9, but unfortunatly reverting to
	 * epoll_create(..) also means that we lose the possibility to
	 * directly set the EPOLL_CLOEXEC, so try and do it anyway but through
	 * fcntl(..).
	 */
	int efd = epoll_create(size);
	LTTNG_ASSERT(fcntl(efd, F_SETFD, flags) != -1);
	return efd;
}
#endif

/*
 * Wait on epoll set with the number of fd registered to the lttng_poll_event
 * data structure (events).
 */
extern int compat_epoll_wait(struct lttng_poll_event *events, int timeout, bool interruptible);
#define lttng_poll_wait(events, timeout)	       compat_epoll_wait(events, timeout, false)
#define lttng_poll_wait_interruptible(events, timeout) compat_epoll_wait(events, timeout, true)

/*
 * Add a fd to the epoll set and resize the epoll_event structure if needed.
 */
extern int compat_epoll_add(struct lttng_poll_event *events, int fd, uint32_t req_events);
#define lttng_poll_add(events, fd, req_events) compat_epoll_add(events, fd, req_events)

/*
 * Remove a fd from the epoll set.
 */
extern int compat_epoll_del(struct lttng_poll_event *events, int fd);
#define lttng_poll_del(events, fd) compat_epoll_del(events, fd)

/*
 * Modify an fd's events in the epoll set.
 */
extern int compat_epoll_mod(struct lttng_poll_event *events, int fd, uint32_t req_events);
#define lttng_poll_mod(events, fd, req_events) compat_epoll_mod(events, fd, req_events)

/*
 * Set up the poll set limits variable poll_max_size
 */
extern int compat_epoll_set_max_size();
#define lttng_poll_set_max_size() compat_epoll_set_max_size()

/*
 * This function memset with zero the structure since it can be reused at each
 * round of a main loop. Being in a loop and using a non static number of fds,
 * this function must be called to insure coherent events with associted fds.
 */
static inline void lttng_poll_reset(struct lttng_poll_event *events)
{
	if (events && events->events) {
		memset(events->events, 0, events->nb_fd * sizeof(struct epoll_event));
	}
}

/*
 * Initialize an already allocated poll event data structure. For epoll(), the
 * epfd is set to -1 to indicate that it's not usable.
 */
static inline void lttng_poll_init(struct lttng_poll_event *events)
{
	memset(events, 0, sizeof(struct lttng_poll_event));
	/* Set fd to -1 so if clean before created, we don't close 0. */
	events->epfd = -1;
}

/*
 * Clean the events structure of a lttng_poll_event. It's the caller
 * responsability to free the lttng_poll_event memory.
 */
static inline void lttng_poll_clean(struct lttng_poll_event *events)
{
	int ret;

	if (!events) {
		return;
	}

	if (events->epfd >= 0) {
		ret = close(events->epfd);
		if (ret) {
			PERROR("close");
		}
	}

	__lttng_poll_free((void *) events->events);
}

#else /* HAVE_EPOLL */
/*
 * Fallback on poll(2) API
 */

#include <poll.h>
#include <stdint.h>

enum {
	/* Polling variables compatibility for poll */
	LPOLLIN = POLLIN,
	LPOLLPRI = POLLPRI,
	LPOLLOUT = POLLOUT,
	LPOLLRDNORM = POLLRDNORM,
	LPOLLRDBAND = POLLRDBAND,
	LPOLLWRNORM = POLLWRNORM,
	LPOLLWRBAND = POLLWRBAND,
#ifdef __USE_GNU
	LPOLLMSG = POLLMSG,
	LPOLLRDHUP = POLLRDHUP,
#else
	LPOLLMSG = 0,
	LPOLLRDHUP = 0,
#endif /* __USE_GNU */
	LPOLLERR = POLLERR,
	LPOLLHUP = POLLHUP | POLLNVAL,
	/* Close on exec feature does not exist for poll(2) */
	LTTNG_CLOEXEC = 0xdead,
};

struct compat_poll_event_array {
	uint32_t nb_fd; /* Current number of fd in events */
	uint32_t alloc_size; /* Size of events array */
	/* Initial size of the pollset. We never shrink below that. */
	uint32_t init_size;
	struct pollfd *events;
};

struct compat_poll_event {
	/*
	 * Modified by the wait action. Updated using current fields if the
	 * need_update flag is set.
	 */
	struct compat_poll_event_array wait;
	/*
	 * This is modified by add/del actions being the _current_ flow of
	 * execution before a poll wait is done.
	 */
	struct compat_poll_event_array current;

	/* Indicate if wait.events need to be updated from current. */
	int need_update:1;
};
#define lttng_poll_event			       compat_poll_event

static inline int
__lttng_poll_get_prev_fd(struct lttng_poll_event *events, int index, uint32_t nb_fd)
{
	LTTNG_ASSERT(events);
	LTTNG_ASSERT(index != nb_fd);

	if (index == 0 || nb_fd == 0) {
		return -1;
	} else {
		return events->current.events[index - 1].fd;
	}
}

/*
 * For the following calls, consider 'e' to be a lttng_poll_event pointer and i
 * being the index of the events array.
 * LTTNG_POLL_GETNB is always used after lttng_poll_wait, thus we can use the
 * current list for test compatibility purposes.
 */
#define LTTNG_POLL_GETFD(e, i)			       LTTNG_REF(e)->wait.events[i].fd
#define LTTNG_POLL_GETEV(e, i)			       LTTNG_REF(e)->wait.events[i].revents
#define LTTNG_POLL_GETNB(e)			       LTTNG_REF(e)->current.nb_fd
#define LTTNG_POLL_GETSZ(e)			       LTTNG_REF(e)->wait.events_size
#define LTTNG_POLL_GET_PREV_FD(e, i, nb_fd)	       __lttng_poll_get_prev_fd(LTTNG_REF(e), i, nb_fd)

/*
 * Create a pollfd structure of size 'size'.
 */
extern int compat_poll_create(struct lttng_poll_event *events, int size);
#define lttng_poll_create(events, size, flags)	       compat_poll_create(events, size)

/*
 * Wait on poll(2) event with nb_fd registered to the lttng_poll_event data
 * structure.
 */
extern int compat_poll_wait(struct lttng_poll_event *events, int timeout, bool interruptible);
#define lttng_poll_wait(events, timeout)	       compat_poll_wait(events, timeout, false)
#define lttng_poll_wait_interruptible(events, timeout) compat_poll_wait(events, timeout, true)

/*
 * Add the fd to the pollfd structure. Resize if needed.
 */
extern int compat_poll_add(struct lttng_poll_event *events, int fd, uint32_t req_events);
#define lttng_poll_add(events, fd, req_events)	       compat_poll_add(events, fd, req_events)

/*
 * Remove the fd from the pollfd. Memory allocation is done to recreate a new
 * pollfd, data is copied from the old pollfd to the new and, finally, the old
 * one is freed().
 */
extern int compat_poll_del(struct lttng_poll_event *events, int fd);
#define lttng_poll_del(events, fd)		       compat_poll_del(events, fd)

/*
 * Modify an fd's events in the poll set.
 */
extern int compat_poll_mod(struct lttng_poll_event *events, int fd, uint32_t req_events);
#define lttng_poll_mod(events, fd, req_events)	       compat_poll_mod(events, fd, req_events)

/*
 * Set up the poll set limits variable poll_max_size
 */
extern int compat_poll_set_max_size(void);
#define lttng_poll_set_max_size()		       compat_poll_set_max_size()

/*
 * No need to reset a pollfd structure for poll(2)
 */
static inline void lttng_poll_reset(struct lttng_poll_event *events __attribute__((unused)))
{
}

/*
 * Initialize an already allocated poll event data structure.
 */
static inline void lttng_poll_init(struct lttng_poll_event *events)
{
	memset(events, 0, sizeof(struct lttng_poll_event));
}

/*
 * Clean the events structure of a lttng_poll_event. It's the caller
 * responsability to free the lttng_poll_event memory.
 */
static inline void lttng_poll_clean(struct lttng_poll_event *events)
{
	if (events) {
		__lttng_poll_free((void *) events->wait.events);
		__lttng_poll_free((void *) events->current.events);
	}
}

#endif /* HAVE_EPOLL */

#endif /* _LTT_POLL_H */
Commit	Line	Data
	1	/*
	2	* Copyright (C) 2011 EfficiOS Inc.
	3	*
	4	* SPDX-License-Identifier: LGPL-2.1-only
	5	*
	6	*/
	7
	8	#ifndef _LTT_POLL_H
	9	#define _LTT_POLL_H
	10
	11	#include <common/common.hpp>
	12
	13	#include <string.h>
	14	#include <unistd.h>
	15
	16	/*
	17	* Used by lttng_poll_clean to free the events structure in a lttng_poll_event.
	18	*/
	19	static inline void __lttng_poll_free(void *events)
	20	{
	21	free(events);
	22	}
	23
	24	/*
	25	* epoll(7) implementation.
	26	*/
	27	#ifdef HAVE_EPOLL
	28	#include <common/compat/fcntl.hpp>
	29
	30	#include <features.h>
	31	#include <stdio.h>
	32	#include <sys/epoll.h>
	33
	34	/* See man epoll(7) for this define path */
	35	#define COMPAT_EPOLL_PROC_PATH "/proc/sys/fs/epoll/max_user_watches"
	36
	37	enum {
	38	/* Polling variables compatibility for epoll */
	39	LPOLLIN = EPOLLIN,
	40	LPOLLPRI = EPOLLPRI,
	41	LPOLLOUT = EPOLLOUT,
	42	LPOLLRDNORM = EPOLLRDNORM,
	43	LPOLLRDBAND = EPOLLRDBAND,
	44	LPOLLWRNORM = EPOLLWRNORM,
	45	LPOLLWRBAND = EPOLLWRBAND,
	46	LPOLLMSG = EPOLLMSG,
	47	LPOLLERR = EPOLLERR,
	48	LPOLLHUP = EPOLLHUP,
	49	LPOLLNVAL = EPOLLHUP,
	50	LPOLLRDHUP = EPOLLRDHUP,
	51	/* Close on exec feature of epoll */
	52	#if defined(HAVE_EPOLL_CREATE1) && defined(EPOLL_CLOEXEC)
	53	LTTNG_CLOEXEC = EPOLL_CLOEXEC,
	54	#else
	55	/*
	56	* EPOLL_CLOEXEC was added in glibc 2.8 (usually used in conjunction with
	57	* epoll_create1(..)), but since neither EPOLL_CLOEXEC exists nor
	58	* epoll_create1(..), we set it to FD_CLOEXEC so that we can pass it
	59	* directly to fcntl(..) instead.
	60	*/
	61	LTTNG_CLOEXEC = FD_CLOEXEC,
	62	#endif
	63	};
	64
	65	struct compat_epoll_event {
	66	int epfd;
	67	uint32_t nb_fd; /* Current number of fd in events */
	68	uint32_t alloc_size; /* Size of events array */
	69	uint32_t init_size; /* Initial size of events array */
	70	struct epoll_event *events;
	71	};
	72	#define lttng_poll_event compat_epoll_event
	73
	74	static inline int
	75	__lttng_epoll_get_prev_fd(struct lttng_poll_event *events, int index, uint32_t nb_fd)
	76	{
	77	LTTNG_ASSERT(events);
	78	LTTNG_ASSERT(index != nb_fd);
	79
	80	if (index == 0 \|\| nb_fd == 0) {
	81	return -1;
	82	} else {
	83	return events->events[index - 1].data.fd;
	84	}
	85	}
	86
	87	/*
	88	* For the following calls, consider 'e' to be a lttng_poll_event pointer and i
	89	* being the index of the events array.
	90	*/
	91	#define LTTNG_POLL_GETFD(e, i) LTTNG_REF(e)->events[i].data.fd
	92	#define LTTNG_POLL_GETEV(e, i) LTTNG_REF(e)->events[i].events
	93	#define LTTNG_POLL_GETNB(e) LTTNG_REF(e)->nb_fd
	94	#define LTTNG_POLL_GETSZ(e) LTTNG_REF(e)->events_size
	95	#define LTTNG_POLL_GET_PREV_FD(e, i, nb_fd) __lttng_epoll_get_prev_fd(LTTNG_REF(e), i, nb_fd)
	96
	97	/* Create the epoll set. */
	98	extern int compat_epoll_create(struct lttng_poll_event *events, int size, int flags);
	99	#define lttng_poll_create(events, size, flags) compat_epoll_create(events, size, flags)
	100
	101	#if defined(HAVE_EPOLL_CREATE1) && defined(EPOLL_CLOEXEC)
	102	static inline int compat_glibc_epoll_create(int size __attribute__((unused)), int flags)
	103	{
	104	return epoll_create1(flags);
	105	}
	106	#else
	107	static inline int compat_glibc_epoll_create(int size, int flags)
	108	{
	109	/*
	110	* epoll_create1 was added in glibc 2.9, but unfortunatly reverting to
	111	* epoll_create(..) also means that we lose the possibility to
	112	* directly set the EPOLL_CLOEXEC, so try and do it anyway but through
	113	* fcntl(..).
	114	*/
	115	int efd = epoll_create(size);
	116	LTTNG_ASSERT(fcntl(efd, F_SETFD, flags) != -1);
	117	return efd;
	118	}
	119	#endif
	120
	121	/*
	122	* Wait on epoll set with the number of fd registered to the lttng_poll_event
	123	* data structure (events).
	124	*/
	125	extern int compat_epoll_wait(struct lttng_poll_event *events, int timeout, bool interruptible);
	126	#define lttng_poll_wait(events, timeout) compat_epoll_wait(events, timeout, false)
	127	#define lttng_poll_wait_interruptible(events, timeout) compat_epoll_wait(events, timeout, true)
	128
	129	/*
	130	* Add a fd to the epoll set and resize the epoll_event structure if needed.
	131	*/
	132	extern int compat_epoll_add(struct lttng_poll_event *events, int fd, uint32_t req_events);
	133	#define lttng_poll_add(events, fd, req_events) compat_epoll_add(events, fd, req_events)
	134
	135	/*
	136	* Remove a fd from the epoll set.
	137	*/
	138	extern int compat_epoll_del(struct lttng_poll_event *events, int fd);
	139	#define lttng_poll_del(events, fd) compat_epoll_del(events, fd)
	140
	141	/*
	142	* Modify an fd's events in the epoll set.
	143	*/
	144	extern int compat_epoll_mod(struct lttng_poll_event *events, int fd, uint32_t req_events);
	145	#define lttng_poll_mod(events, fd, req_events) compat_epoll_mod(events, fd, req_events)
	146
	147	/*
	148	* Set up the poll set limits variable poll_max_size
	149	*/
	150	extern int compat_epoll_set_max_size();
	151	#define lttng_poll_set_max_size() compat_epoll_set_max_size()
	152
	153	/*
	154	* This function memset with zero the structure since it can be reused at each
	155	* round of a main loop. Being in a loop and using a non static number of fds,
	156	* this function must be called to insure coherent events with associted fds.
	157	*/
	158	static inline void lttng_poll_reset(struct lttng_poll_event *events)
	159	{
	160	if (events && events->events) {
	161	memset(events->events, 0, events->nb_fd * sizeof(struct epoll_event));
	162	}
	163	}
	164
	165	/*
	166	* Initialize an already allocated poll event data structure. For epoll(), the
	167	* epfd is set to -1 to indicate that it's not usable.
	168	*/
	169	static inline void lttng_poll_init(struct lttng_poll_event *events)
	170	{
	171	memset(events, 0, sizeof(struct lttng_poll_event));
	172	/* Set fd to -1 so if clean before created, we don't close 0. */
	173	events->epfd = -1;
	174	}
	175
	176	/*
	177	* Clean the events structure of a lttng_poll_event. It's the caller
	178	* responsability to free the lttng_poll_event memory.
	179	*/
	180	static inline void lttng_poll_clean(struct lttng_poll_event *events)
	181	{
	182	int ret;
	183
	184	if (!events) {
	185	return;
	186	}
	187
	188	if (events->epfd >= 0) {
	189	ret = close(events->epfd);
	190	if (ret) {
	191	PERROR("close");
	192	}
	193	}
	194
	195	__lttng_poll_free((void *) events->events);
	196	}
	197
	198	#else /* HAVE_EPOLL */
	199	/*
	200	* Fallback on poll(2) API
	201	*/
	202
	203	#include <poll.h>
	204	#include <stdint.h>
	205
	206	enum {
	207	/* Polling variables compatibility for poll */
	208	LPOLLIN = POLLIN,
	209	LPOLLPRI = POLLPRI,
	210	LPOLLOUT = POLLOUT,
	211	LPOLLRDNORM = POLLRDNORM,
	212	LPOLLRDBAND = POLLRDBAND,
	213	LPOLLWRNORM = POLLWRNORM,
	214	LPOLLWRBAND = POLLWRBAND,
	215	#ifdef __USE_GNU
	216	LPOLLMSG = POLLMSG,
	217	LPOLLRDHUP = POLLRDHUP,
	218	#else
	219	LPOLLMSG = 0,
	220	LPOLLRDHUP = 0,
	221	#endif /* __USE_GNU */
	222	LPOLLERR = POLLERR,
	223	LPOLLHUP = POLLHUP \| POLLNVAL,
	224	/* Close on exec feature does not exist for poll(2) */
	225	LTTNG_CLOEXEC = 0xdead,
	226	};
	227
	228	struct compat_poll_event_array {
	229	uint32_t nb_fd; /* Current number of fd in events */
	230	uint32_t alloc_size; /* Size of events array */
	231	/* Initial size of the pollset. We never shrink below that. */
	232	uint32_t init_size;
	233	struct pollfd *events;
	234	};
	235
	236	struct compat_poll_event {
	237	/*
	238	* Modified by the wait action. Updated using current fields if the
	239	* need_update flag is set.
	240	*/
	241	struct compat_poll_event_array wait;
	242	/*
	243	* This is modified by add/del actions being the _current_ flow of
	244	* execution before a poll wait is done.
	245	*/
	246	struct compat_poll_event_array current;
	247
	248	/* Indicate if wait.events need to be updated from current. */
	249	int need_update:1;
	250	};
	251	#define lttng_poll_event compat_poll_event
	252
	253	static inline int
	254	__lttng_poll_get_prev_fd(struct lttng_poll_event *events, int index, uint32_t nb_fd)
	255	{
	256	LTTNG_ASSERT(events);
	257	LTTNG_ASSERT(index != nb_fd);
	258
	259	if (index == 0 \|\| nb_fd == 0) {
	260	return -1;
	261	} else {
	262	return events->current.events[index - 1].fd;
	263	}
	264	}
	265
	266	/*
	267	* For the following calls, consider 'e' to be a lttng_poll_event pointer and i
	268	* being the index of the events array.
	269	* LTTNG_POLL_GETNB is always used after lttng_poll_wait, thus we can use the
	270	* current list for test compatibility purposes.
	271	*/
	272	#define LTTNG_POLL_GETFD(e, i) LTTNG_REF(e)->wait.events[i].fd
	273	#define LTTNG_POLL_GETEV(e, i) LTTNG_REF(e)->wait.events[i].revents
	274	#define LTTNG_POLL_GETNB(e) LTTNG_REF(e)->current.nb_fd
	275	#define LTTNG_POLL_GETSZ(e) LTTNG_REF(e)->wait.events_size
	276	#define LTTNG_POLL_GET_PREV_FD(e, i, nb_fd) __lttng_poll_get_prev_fd(LTTNG_REF(e), i, nb_fd)
	277
	278	/*
	279	* Create a pollfd structure of size 'size'.
	280	*/
	281	extern int compat_poll_create(struct lttng_poll_event *events, int size);
	282	#define lttng_poll_create(events, size, flags) compat_poll_create(events, size)
	283
	284	/*
	285	* Wait on poll(2) event with nb_fd registered to the lttng_poll_event data
	286	* structure.
	287	*/
	288	extern int compat_poll_wait(struct lttng_poll_event *events, int timeout, bool interruptible);
	289	#define lttng_poll_wait(events, timeout) compat_poll_wait(events, timeout, false)
	290	#define lttng_poll_wait_interruptible(events, timeout) compat_poll_wait(events, timeout, true)
	291
	292	/*
	293	* Add the fd to the pollfd structure. Resize if needed.
	294	*/
	295	extern int compat_poll_add(struct lttng_poll_event *events, int fd, uint32_t req_events);
	296	#define lttng_poll_add(events, fd, req_events) compat_poll_add(events, fd, req_events)
	297
	298	/*
	299	* Remove the fd from the pollfd. Memory allocation is done to recreate a new
	300	* pollfd, data is copied from the old pollfd to the new and, finally, the old
	301	* one is freed().
	302	*/
	303	extern int compat_poll_del(struct lttng_poll_event *events, int fd);
	304	#define lttng_poll_del(events, fd) compat_poll_del(events, fd)
	305
	306	/*
	307	* Modify an fd's events in the poll set.
	308	*/
	309	extern int compat_poll_mod(struct lttng_poll_event *events, int fd, uint32_t req_events);
	310	#define lttng_poll_mod(events, fd, req_events) compat_poll_mod(events, fd, req_events)
	311
	312	/*
	313	* Set up the poll set limits variable poll_max_size
	314	*/
	315	extern int compat_poll_set_max_size(void);
	316	#define lttng_poll_set_max_size() compat_poll_set_max_size()
	317
	318	/*
	319	* No need to reset a pollfd structure for poll(2)
	320	*/
	321	static inline void lttng_poll_reset(struct lttng_poll_event *events __attribute__((unused)))
	322	{
	323	}
	324
	325	/*
	326	* Initialize an already allocated poll event data structure.
	327	*/
	328	static inline void lttng_poll_init(struct lttng_poll_event *events)
	329	{
	330	memset(events, 0, sizeof(struct lttng_poll_event));
	331	}
	332
	333	/*
	334	* Clean the events structure of a lttng_poll_event. It's the caller
	335	* responsability to free the lttng_poll_event memory.
	336	*/
	337	static inline void lttng_poll_clean(struct lttng_poll_event *events)
	338	{
	339	if (events) {
	340	__lttng_poll_free((void *) events->wait.events);
	341	__lttng_poll_free((void *) events->current.events);
	342	}
	343	}
	344
	345	#endif /* HAVE_EPOLL */
	346
	347	#endif /* _LTT_POLL_H */