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

#include <common/common.hpp>

/*
 * 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 <sys/epoll.h>
#include <stdio.h>
#include <features.h>
#include <common/compat/fcntl.hpp>

/* 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 <string.h>
	12	#include <unistd.h>
	13
	14	#include <common/common.hpp>
	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 <sys/epoll.h>
	29	#include <stdio.h>
	30	#include <features.h>
	31	#include <common/compat/fcntl.hpp>
	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 __lttng_epoll_get_prev_fd(struct lttng_poll_event *events,
	74	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) \
	95	__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,
	99	int size, int flags);
	100	#define lttng_poll_create(events, size, flags) \
	101	compat_epoll_create(events, size, flags)
	102
	103	#if defined(HAVE_EPOLL_CREATE1) && defined(EPOLL_CLOEXEC)
	104	static inline int compat_glibc_epoll_create(int size __attribute__((unused)),
	105	int flags)
	106	{
	107	return epoll_create1(flags);
	108	}
	109	#else
	110	static inline int compat_glibc_epoll_create(int size, int flags)
	111	{
	112	/*
	113	* epoll_create1 was added in glibc 2.9, but unfortunatly reverting to
	114	* epoll_create(..) also means that we lose the possibility to
	115	* directly set the EPOLL_CLOEXEC, so try and do it anyway but through
	116	* fcntl(..).
	117	*/
	118	int efd = epoll_create(size);
	119	LTTNG_ASSERT(fcntl(efd, F_SETFD, flags) != -1);
	120	return efd;
	121	}
	122	#endif
	123
	124	/*
	125	* Wait on epoll set with the number of fd registered to the lttng_poll_event
	126	* data structure (events).
	127	*/
	128	extern int compat_epoll_wait(struct lttng_poll_event *events, int timeout,
	129	bool interruptible);
	130	#define lttng_poll_wait(events, timeout) \
	131	compat_epoll_wait(events, timeout, false)
	132	#define lttng_poll_wait_interruptible(events, timeout) \
	133	compat_epoll_wait(events, timeout, true)
	134
	135	/*
	136	* Add a fd to the epoll set and resize the epoll_event structure if needed.
	137	*/
	138	extern int compat_epoll_add(struct lttng_poll_event *events,
	139	int fd, uint32_t req_events);
	140	#define lttng_poll_add(events, fd, req_events) \
	141	compat_epoll_add(events, fd, req_events)
	142
	143	/*
	144	* Remove a fd from the epoll set.
	145	*/
	146	extern int compat_epoll_del(struct lttng_poll_event *events, int fd);
	147	#define lttng_poll_del(events, fd) \
	148	compat_epoll_del(events, fd)
	149
	150	/*
	151	* Modify an fd's events in the epoll set.
	152	*/
	153	extern int compat_epoll_mod(struct lttng_poll_event *events,
	154	int fd, uint32_t req_events);
	155	#define lttng_poll_mod(events, fd, req_events) \
	156	compat_epoll_mod(events, fd, req_events)
	157
	158	/*
	159	* Set up the poll set limits variable poll_max_size
	160	*/
	161	extern int compat_epoll_set_max_size();
	162	#define lttng_poll_set_max_size() \
	163	compat_epoll_set_max_size()
	164
	165	/*
	166	* This function memset with zero the structure since it can be reused at each
	167	* round of a main loop. Being in a loop and using a non static number of fds,
	168	* this function must be called to insure coherent events with associted fds.
	169	*/
	170	static inline void lttng_poll_reset(struct lttng_poll_event *events)
	171	{
	172	if (events && events->events) {
	173	memset(events->events, 0,
	174	events->nb_fd * sizeof(struct epoll_event));
	175	}
	176	}
	177
	178	/*
	179	* Initialize an already allocated poll event data structure. For epoll(), the
	180	* epfd is set to -1 to indicate that it's not usable.
	181	*/
	182	static inline void lttng_poll_init(struct lttng_poll_event *events)
	183	{
	184	memset(events, 0, sizeof(struct lttng_poll_event));
	185	/* Set fd to -1 so if clean before created, we don't close 0. */
	186	events->epfd = -1;
	187	}
	188
	189	/*
	190	* Clean the events structure of a lttng_poll_event. It's the caller
	191	* responsability to free the lttng_poll_event memory.
	192	*/
	193	static inline void lttng_poll_clean(struct lttng_poll_event *events)
	194	{
	195	int ret;
	196
	197	if (!events) {
	198	return;
	199	}
	200
	201	if (events->epfd >= 0) {
	202	ret = close(events->epfd);
	203	if (ret) {
	204	PERROR("close");
	205	}
	206	}
	207
	208	__lttng_poll_free((void *) events->events);
	209	}
	210
	211	#else /* HAVE_EPOLL */
	212	/*
	213	* Fallback on poll(2) API
	214	*/
	215
	216	#include <poll.h>
	217	#include <stdint.h>
	218
	219	enum {
	220	/* Polling variables compatibility for poll */
	221	LPOLLIN = POLLIN,
	222	LPOLLPRI = POLLPRI,
	223	LPOLLOUT = POLLOUT,
	224	LPOLLRDNORM = POLLRDNORM,
	225	LPOLLRDBAND = POLLRDBAND,
	226	LPOLLWRNORM = POLLWRNORM,
	227	LPOLLWRBAND = POLLWRBAND,
	228	#ifdef __USE_GNU
	229	LPOLLMSG = POLLMSG,
	230	LPOLLRDHUP = POLLRDHUP,
	231	#else
	232	LPOLLMSG = 0,
	233	LPOLLRDHUP = 0,
	234	#endif /* __USE_GNU */
	235	LPOLLERR = POLLERR,
	236	LPOLLHUP = POLLHUP \| POLLNVAL,
	237	/* Close on exec feature does not exist for poll(2) */
	238	LTTNG_CLOEXEC = 0xdead,
	239	};
	240
	241	struct compat_poll_event_array {
	242	uint32_t nb_fd; /* Current number of fd in events */
	243	uint32_t alloc_size; /* Size of events array */
	244	/* Initial size of the pollset. We never shrink below that. */
	245	uint32_t init_size;
	246	struct pollfd *events;
	247	};
	248
	249	struct compat_poll_event {
	250	/*
	251	* Modified by the wait action. Updated using current fields if the
	252	* need_update flag is set.
	253	*/
	254	struct compat_poll_event_array wait;
	255	/*
	256	* This is modified by add/del actions being the _current_ flow of
	257	* execution before a poll wait is done.
	258	*/
	259	struct compat_poll_event_array current;
	260
	261	/* Indicate if wait.events need to be updated from current. */
	262	int need_update:1;
	263	};
	264	#define lttng_poll_event compat_poll_event
	265
	266	static inline int __lttng_poll_get_prev_fd(struct lttng_poll_event *events,
	267	int index, uint32_t nb_fd)
	268	{
	269	LTTNG_ASSERT(events);
	270	LTTNG_ASSERT(index != nb_fd);
	271
	272	if (index == 0 \|\| nb_fd == 0) {
	273	return -1;
	274	} else {
	275	return events->current.events[index - 1].fd;
	276	}
	277	}
	278
	279	/*
	280	* For the following calls, consider 'e' to be a lttng_poll_event pointer and i
	281	* being the index of the events array.
	282	* LTTNG_POLL_GETNB is always used after lttng_poll_wait, thus we can use the
	283	* current list for test compatibility purposes.
	284	*/
	285	#define LTTNG_POLL_GETFD(e, i) LTTNG_REF(e)->wait.events[i].fd
	286	#define LTTNG_POLL_GETEV(e, i) LTTNG_REF(e)->wait.events[i].revents
	287	#define LTTNG_POLL_GETNB(e) LTTNG_REF(e)->current.nb_fd
	288	#define LTTNG_POLL_GETSZ(e) LTTNG_REF(e)->wait.events_size
	289	#define LTTNG_POLL_GET_PREV_FD(e, i, nb_fd) \
	290	__lttng_poll_get_prev_fd(LTTNG_REF(e), i, nb_fd)
	291
	292	/*
	293	* Create a pollfd structure of size 'size'.
	294	*/
	295	extern int compat_poll_create(struct lttng_poll_event *events, int size);
	296	#define lttng_poll_create(events, size, flags) \
	297	compat_poll_create(events, size)
	298
	299	/*
	300	* Wait on poll(2) event with nb_fd registered to the lttng_poll_event data
	301	* structure.
	302	*/
	303	extern int compat_poll_wait(struct lttng_poll_event *events, int timeout,
	304	bool interruptible);
	305	#define lttng_poll_wait(events, timeout) \
	306	compat_poll_wait(events, timeout, false)
	307	#define lttng_poll_wait_interruptible(events, timeout) \
	308	compat_poll_wait(events, timeout, true)
	309
	310	/*
	311	* Add the fd to the pollfd structure. Resize if needed.
	312	*/
	313	extern int compat_poll_add(struct lttng_poll_event *events,
	314	int fd, uint32_t req_events);
	315	#define lttng_poll_add(events, fd, req_events) \
	316	compat_poll_add(events, fd, req_events)
	317
	318	/*
	319	* Remove the fd from the pollfd. Memory allocation is done to recreate a new
	320	* pollfd, data is copied from the old pollfd to the new and, finally, the old
	321	* one is freed().
	322	*/
	323	extern int compat_poll_del(struct lttng_poll_event *events, int fd);
	324	#define lttng_poll_del(events, fd) \
	325	compat_poll_del(events, fd)
	326
	327	/*
	328	* Modify an fd's events in the poll set.
	329	*/
	330	extern int compat_poll_mod(struct lttng_poll_event *events,
	331	int fd, uint32_t req_events);
	332	#define lttng_poll_mod(events, fd, req_events) \
	333	compat_poll_mod(events, fd, req_events)
	334
	335	/*
	336	* Set up the poll set limits variable poll_max_size
	337	*/
	338	extern int compat_poll_set_max_size(void);
	339	#define lttng_poll_set_max_size() \
	340	compat_poll_set_max_size()
	341
	342	/*
	343	* No need to reset a pollfd structure for poll(2)
	344	*/
	345	static inline void lttng_poll_reset(
	346	struct lttng_poll_event *events __attribute__((unused)))
	347	{}
	348
	349	/*
	350	* Initialize an already allocated poll event data structure.
	351	*/
	352	static inline void lttng_poll_init(struct lttng_poll_event *events)
	353	{
	354	memset(events, 0, sizeof(struct lttng_poll_event));
	355	}
	356
	357	/*
	358	* Clean the events structure of a lttng_poll_event. It's the caller
	359	* responsability to free the lttng_poll_event memory.
	360	*/
	361	static inline void lttng_poll_clean(struct lttng_poll_event *events)
	362	{
	363	if (events) {
	364	__lttng_poll_free((void *) events->wait.events);
	365	__lttng_poll_free((void *) events->current.events);
	366	}
	367	}
	368
	369	#endif /* HAVE_EPOLL */
	370
	371	#endif /* _LTT_POLL_H */