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