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

/*
 * Copyright (C) 2011 David Goulet <david.goulet@polymtl.ca>
 *
 * SPDX-License-Identifier: GPL-2.0-only
 *
 */

#ifndef _LTT_POLL_H
#define _LTT_POLL_H

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

#include <common/common.h>

#ifdef __cplusplus
extern "C" {
#endif

/*
 * 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);
}

#ifdef __cplusplus
}
#endif

/*
 * epoll(7) implementation.
 */
#ifdef HAVE_EPOLL
#include <sys/epoll.h>
#include <stdio.h>
#include <features.h>
#include <common/compat/fcntl.h>

#ifdef __cplusplus
extern "C" {
#endif

/* 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(void);
#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);
}

#ifdef __cplusplus
}
#endif

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

/* Needed for some poll event values */
#ifndef __USE_XOPEN
#define __USE_XOPEN
#endif

/* Needed for some poll event values */
#ifndef __USE_GNU
#define __USE_GNU
#endif

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

#ifdef __cplusplus
extern "C" {
#endif

enum {
	/* Polling variables compatibility for poll */
	LPOLLIN = POLLIN,
	LPOLLPRI = POLLPRI,
	LPOLLOUT = POLLOUT,
	LPOLLRDNORM = POLLRDNORM,
	LPOLLRDBAND = POLLRDBAND,
	LPOLLWRNORM = POLLWRNORM,
	LPOLLWRBAND = POLLWRBAND,
#if __linux__
	LPOLLMSG = POLLMSG,
	LPOLLRDHUP = POLLRDHUP,
#elif (defined(__FreeBSD__) || defined(__CYGWIN__) || defined(__sun__) || defined(__APPLE__))
	LPOLLMSG = 0,
	LPOLLRDHUP = 0,
#else
#error "Please add support for your OS."
#endif /* __linux__ */
	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)
{}

/*
 * 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);
	}
}

#ifdef __cplusplus
}
#endif

#endif /* HAVE_EPOLL */

#endif /* _LTT_POLL_H */
Commit	Line	Data
	1	/*
	2	* Copyright (C) 2011 David Goulet <david.goulet@polymtl.ca>
	3	*
	4	* SPDX-License-Identifier: GPL-2.0-only
	5	*
	6	*/
	7
	8	#ifndef _LTT_POLL_H
	9	#define _LTT_POLL_H
	10
	11	#include <string.h>
	12	#include <unistd.h>
	13
	14	#include <common/common.h>
	15
	16	#ifdef __cplusplus
	17	extern "C" {
	18	#endif
	19
	20	/*
	21	* Used by lttng_poll_clean to free the events structure in a lttng_poll_event.
	22	*/
	23	static inline void __lttng_poll_free(void *events)
	24	{
	25	free(events);
	26	}
	27
	28	#ifdef __cplusplus
	29	}
	30	#endif
	31
	32	/*
	33	* epoll(7) implementation.
	34	*/
	35	#ifdef HAVE_EPOLL
	36	#include <sys/epoll.h>
	37	#include <stdio.h>
	38	#include <features.h>
	39	#include <common/compat/fcntl.h>
	40
	41	#ifdef __cplusplus
	42	extern "C" {
	43	#endif
	44
	45	/* See man epoll(7) for this define path */
	46	#define COMPAT_EPOLL_PROC_PATH "/proc/sys/fs/epoll/max_user_watches"
	47
	48	enum {
	49	/* Polling variables compatibility for epoll */
	50	LPOLLIN = EPOLLIN,
	51	LPOLLPRI = EPOLLPRI,
	52	LPOLLOUT = EPOLLOUT,
	53	LPOLLRDNORM = EPOLLRDNORM,
	54	LPOLLRDBAND = EPOLLRDBAND,
	55	LPOLLWRNORM = EPOLLWRNORM,
	56	LPOLLWRBAND = EPOLLWRBAND,
	57	LPOLLMSG = EPOLLMSG,
	58	LPOLLERR = EPOLLERR,
	59	LPOLLHUP = EPOLLHUP,
	60	LPOLLNVAL = EPOLLHUP,
	61	LPOLLRDHUP = EPOLLRDHUP,
	62	/* Close on exec feature of epoll */
	63	#if defined(HAVE_EPOLL_CREATE1) && defined(EPOLL_CLOEXEC)
	64	LTTNG_CLOEXEC = EPOLL_CLOEXEC,
	65	#else
	66	/*
	67	* EPOLL_CLOEXEC was added in glibc 2.8 (usually used in conjunction with
	68	* epoll_create1(..)), but since neither EPOLL_CLOEXEC exists nor
	69	* epoll_create1(..), we set it to FD_CLOEXEC so that we can pass it
	70	* directly to fcntl(..) instead.
	71	*/
	72	LTTNG_CLOEXEC = FD_CLOEXEC,
	73	#endif
	74	};
	75
	76	struct compat_epoll_event {
	77	int epfd;
	78	uint32_t nb_fd; /* Current number of fd in events */
	79	uint32_t alloc_size; /* Size of events array */
	80	uint32_t init_size; /* Initial size of events array */
	81	struct epoll_event *events;
	82	};
	83	#define lttng_poll_event compat_epoll_event
	84
	85	static inline int __lttng_epoll_get_prev_fd(struct lttng_poll_event *events,
	86	int index, uint32_t nb_fd)
	87	{
	88	LTTNG_ASSERT(events);
	89	LTTNG_ASSERT(index != nb_fd);
	90
	91	if (index == 0 \|\| nb_fd == 0) {
	92	return -1;
	93	} else {
	94	return events->events[index - 1].data.fd;
	95	}
	96	}
	97
	98	/*
	99	* For the following calls, consider 'e' to be a lttng_poll_event pointer and i
	100	* being the index of the events array.
	101	*/
	102	#define LTTNG_POLL_GETFD(e, i) LTTNG_REF(e)->events[i].data.fd
	103	#define LTTNG_POLL_GETEV(e, i) LTTNG_REF(e)->events[i].events
	104	#define LTTNG_POLL_GETNB(e) LTTNG_REF(e)->nb_fd
	105	#define LTTNG_POLL_GETSZ(e) LTTNG_REF(e)->events_size
	106	#define LTTNG_POLL_GET_PREV_FD(e, i, nb_fd) \
	107	__lttng_epoll_get_prev_fd(LTTNG_REF(e), i, nb_fd)
	108
	109	/* Create the epoll set. */
	110	extern int compat_epoll_create(struct lttng_poll_event *events,
	111	int size, int flags);
	112	#define lttng_poll_create(events, size, flags) \
	113	compat_epoll_create(events, size, flags)
	114
	115	#if defined(HAVE_EPOLL_CREATE1) && defined(EPOLL_CLOEXEC)
	116	static inline int compat_glibc_epoll_create(int size __attribute__((unused)),
	117	int flags)
	118	{
	119	return epoll_create1(flags);
	120	}
	121	#else
	122	static inline int compat_glibc_epoll_create(int size, int flags)
	123	{
	124	/*
	125	* epoll_create1 was added in glibc 2.9, but unfortunatly reverting to
	126	* epoll_create(..) also means that we lose the possibility to
	127	* directly set the EPOLL_CLOEXEC, so try and do it anyway but through
	128	* fcntl(..).
	129	*/
	130	int efd = epoll_create(size);
	131	LTTNG_ASSERT(fcntl(efd, F_SETFD, flags) != -1);
	132	return efd;
	133	}
	134	#endif
	135
	136	/*
	137	* Wait on epoll set with the number of fd registered to the lttng_poll_event
	138	* data structure (events).
	139	*/
	140	extern int compat_epoll_wait(struct lttng_poll_event *events, int timeout,
	141	bool interruptible);
	142	#define lttng_poll_wait(events, timeout) \
	143	compat_epoll_wait(events, timeout, false)
	144	#define lttng_poll_wait_interruptible(events, timeout) \
	145	compat_epoll_wait(events, timeout, true)
	146
	147	/*
	148	* Add a fd to the epoll set and resize the epoll_event structure if needed.
	149	*/
	150	extern int compat_epoll_add(struct lttng_poll_event *events,
	151	int fd, uint32_t req_events);
	152	#define lttng_poll_add(events, fd, req_events) \
	153	compat_epoll_add(events, fd, req_events)
	154
	155	/*
	156	* Remove a fd from the epoll set.
	157	*/
	158	extern int compat_epoll_del(struct lttng_poll_event *events, int fd);
	159	#define lttng_poll_del(events, fd) \
	160	compat_epoll_del(events, fd)
	161
	162	/*
	163	* Modify an fd's events in the epoll set.
	164	*/
	165	extern int compat_epoll_mod(struct lttng_poll_event *events,
	166	int fd, uint32_t req_events);
	167	#define lttng_poll_mod(events, fd, req_events) \
	168	compat_epoll_mod(events, fd, req_events)
	169
	170	/*
	171	* Set up the poll set limits variable poll_max_size
	172	*/
	173	extern int compat_epoll_set_max_size(void);
	174	#define lttng_poll_set_max_size() \
	175	compat_epoll_set_max_size()
	176
	177	/*
	178	* This function memset with zero the structure since it can be reused at each
	179	* round of a main loop. Being in a loop and using a non static number of fds,
	180	* this function must be called to insure coherent events with associted fds.
	181	*/
	182	static inline void lttng_poll_reset(struct lttng_poll_event *events)
	183	{
	184	if (events && events->events) {
	185	memset(events->events, 0,
	186	events->nb_fd * sizeof(struct epoll_event));
	187	}
	188	}
	189
	190	/*
	191	* Initialize an already allocated poll event data structure. For epoll(), the
	192	* epfd is set to -1 to indicate that it's not usable.
	193	*/
	194	static inline void lttng_poll_init(struct lttng_poll_event *events)
	195	{
	196	memset(events, 0, sizeof(struct lttng_poll_event));
	197	/* Set fd to -1 so if clean before created, we don't close 0. */
	198	events->epfd = -1;
	199	}
	200
	201	/*
	202	* Clean the events structure of a lttng_poll_event. It's the caller
	203	* responsability to free the lttng_poll_event memory.
	204	*/
	205	static inline void lttng_poll_clean(struct lttng_poll_event *events)
	206	{
	207	int ret;
	208
	209	if (!events) {
	210	return;
	211	}
	212
	213	if (events->epfd >= 0) {
	214	ret = close(events->epfd);
	215	if (ret) {
	216	PERROR("close");
	217	}
	218	}
	219
	220	__lttng_poll_free((void *) events->events);
	221	}
	222
	223	#ifdef __cplusplus
	224	}
	225	#endif
	226
	227	#else /* HAVE_EPOLL */
	228	/*
	229	* Fallback on poll(2) API
	230	*/
	231
	232	/* Needed for some poll event values */
	233	#ifndef __USE_XOPEN
	234	#define __USE_XOPEN
	235	#endif
	236
	237	/* Needed for some poll event values */
	238	#ifndef __USE_GNU
	239	#define __USE_GNU
	240	#endif
	241
	242	#include <poll.h>
	243	#include <stdint.h>
	244
	245	#ifdef __cplusplus
	246	extern "C" {
	247	#endif
	248
	249	enum {
	250	/* Polling variables compatibility for poll */
	251	LPOLLIN = POLLIN,
	252	LPOLLPRI = POLLPRI,
	253	LPOLLOUT = POLLOUT,
	254	LPOLLRDNORM = POLLRDNORM,
	255	LPOLLRDBAND = POLLRDBAND,
	256	LPOLLWRNORM = POLLWRNORM,
	257	LPOLLWRBAND = POLLWRBAND,
	258	#if __linux__
	259	LPOLLMSG = POLLMSG,
	260	LPOLLRDHUP = POLLRDHUP,
	261	#elif (defined(__FreeBSD__) \|\| defined(__CYGWIN__) \|\| defined(__sun__) \|\| defined(__APPLE__))
	262	LPOLLMSG = 0,
	263	LPOLLRDHUP = 0,
	264	#else
	265	#error "Please add support for your OS."
	266	#endif /* __linux__ */
	267	LPOLLERR = POLLERR,
	268	LPOLLHUP = POLLHUP \| POLLNVAL,
	269	/* Close on exec feature does not exist for poll(2) */
	270	LTTNG_CLOEXEC = 0xdead,
	271	};
	272
	273	struct compat_poll_event_array {
	274	uint32_t nb_fd; /* Current number of fd in events */
	275	uint32_t alloc_size; /* Size of events array */
	276	/* Initial size of the pollset. We never shrink below that. */
	277	uint32_t init_size;
	278	struct pollfd *events;
	279	};
	280
	281	struct compat_poll_event {
	282	/*
	283	* Modified by the wait action. Updated using current fields if the
	284	* need_update flag is set.
	285	*/
	286	struct compat_poll_event_array wait;
	287	/*
	288	* This is modified by add/del actions being the _current_ flow of
	289	* execution before a poll wait is done.
	290	*/
	291	struct compat_poll_event_array current;
	292
	293	/* Indicate if wait.events need to be updated from current. */
	294	int need_update:1;
	295	};
	296	#define lttng_poll_event compat_poll_event
	297
	298	static inline int __lttng_poll_get_prev_fd(struct lttng_poll_event *events,
	299	int index, uint32_t nb_fd)
	300	{
	301	LTTNG_ASSERT(events);
	302	LTTNG_ASSERT(index != nb_fd);
	303
	304	if (index == 0 \|\| nb_fd == 0) {
	305	return -1;
	306	} else {
	307	return events->current.events[index - 1].fd;
	308	}
	309	}
	310
	311	/*
	312	* For the following calls, consider 'e' to be a lttng_poll_event pointer and i
	313	* being the index of the events array.
	314	* LTTNG_POLL_GETNB is always used after lttng_poll_wait, thus we can use the
	315	* current list for test compatibility purposes.
	316	*/
	317	#define LTTNG_POLL_GETFD(e, i) LTTNG_REF(e)->wait.events[i].fd
	318	#define LTTNG_POLL_GETEV(e, i) LTTNG_REF(e)->wait.events[i].revents
	319	#define LTTNG_POLL_GETNB(e) LTTNG_REF(e)->current.nb_fd
	320	#define LTTNG_POLL_GETSZ(e) LTTNG_REF(e)->wait.events_size
	321	#define LTTNG_POLL_GET_PREV_FD(e, i, nb_fd) \
	322	__lttng_poll_get_prev_fd(LTTNG_REF(e), i, nb_fd)
	323
	324	/*
	325	* Create a pollfd structure of size 'size'.
	326	*/
	327	extern int compat_poll_create(struct lttng_poll_event *events, int size);
	328	#define lttng_poll_create(events, size, flags) \
	329	compat_poll_create(events, size)
	330
	331	/*
	332	* Wait on poll(2) event with nb_fd registered to the lttng_poll_event data
	333	* structure.
	334	*/
	335	extern int compat_poll_wait(struct lttng_poll_event *events, int timeout,
	336	bool interruptible);
	337	#define lttng_poll_wait(events, timeout) \
	338	compat_poll_wait(events, timeout, false)
	339	#define lttng_poll_wait_interruptible(events, timeout) \
	340	compat_poll_wait(events, timeout, true)
	341
	342	/*
	343	* Add the fd to the pollfd structure. Resize if needed.
	344	*/
	345	extern int compat_poll_add(struct lttng_poll_event *events,
	346	int fd, uint32_t req_events);
	347	#define lttng_poll_add(events, fd, req_events) \
	348	compat_poll_add(events, fd, req_events)
	349
	350	/*
	351	* Remove the fd from the pollfd. Memory allocation is done to recreate a new
	352	* pollfd, data is copied from the old pollfd to the new and, finally, the old
	353	* one is freed().
	354	*/
	355	extern int compat_poll_del(struct lttng_poll_event *events, int fd);
	356	#define lttng_poll_del(events, fd) \
	357	compat_poll_del(events, fd)
	358
	359	/*
	360	* Modify an fd's events in the poll set.
	361	*/
	362	extern int compat_poll_mod(struct lttng_poll_event *events,
	363	int fd, uint32_t req_events);
	364	#define lttng_poll_mod(events, fd, req_events) \
	365	compat_poll_mod(events, fd, req_events)
	366
	367	/*
	368	* Set up the poll set limits variable poll_max_size
	369	*/
	370	extern int compat_poll_set_max_size(void);
	371	#define lttng_poll_set_max_size() \
	372	compat_poll_set_max_size()
	373
	374	/*
	375	* No need to reset a pollfd structure for poll(2)
	376	*/
	377	static inline void lttng_poll_reset(struct lttng_poll_event *events)
	378	{}
	379
	380	/*
	381	* Initialize an already allocated poll event data structure.
	382	*/
	383	static inline void lttng_poll_init(struct lttng_poll_event *events)
	384	{
	385	memset(events, 0, sizeof(struct lttng_poll_event));
	386	}
	387
	388	/*
	389	* Clean the events structure of a lttng_poll_event. It's the caller
	390	* responsability to free the lttng_poll_event memory.
	391	*/
	392	static inline void lttng_poll_clean(struct lttng_poll_event *events)
	393	{
	394	if (events) {
	395	__lttng_poll_free((void *) events->wait.events);
	396	__lttng_poll_free((void *) events->current.events);
	397	}
	398	}
	399
	400	#ifdef __cplusplus
	401	}
	402	#endif
	403
	404	#endif /* HAVE_EPOLL */
	405
	406	#endif /* _LTT_POLL_H */