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

/*
 * Copyright (C) 2011 - David Goulet <david.goulet@polymtl.ca>
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License, version 2 only,
 * as published by the Free Software Foundation.
 *
 * This program is distributed in the hope that it will be useful, but WITHOUT
 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
 * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for
 * more details.
 *
 * You should have received a copy of the GNU General Public License along
 * with this program; if not, write to the Free Software Foundation, Inc.,
 * 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
 */

#ifndef _LTT_POLL_H
#define _LTT_POLL_H

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

#include <common/common.h>

/*
 * Maximum number of fd we can monitor.
 *
 * For epoll(7), /proc/sys/fs/epoll/max_user_watches (since Linux 2.6.28) will
 * be used for the maximum size of the poll set. If this interface is not
 * available, according to the manpage, the max_user_watches value is 1/25 (4%)
 * of the available low memory divided by the registration cost in bytes which
 * is 90 bytes on a 32-bit kernel and 160 bytes on a 64-bit kernel.
 *
 * For poll(2), the max fds must not exceed RLIMIT_NOFILE given by
 * getrlimit(2).
 */
extern unsigned int poll_max_size;

/*
 * 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.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)
{
	assert(events);
	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. No memory allocation is done here.
 */
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);
	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);
#define lttng_poll_wait(events, timeout) \
	compat_epoll_wait(events, timeout)

/*
 * 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)

/*
 * 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);
}

#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>

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__))
	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)
{
	assert(events);
	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.
 */
#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)->wait.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);
#define lttng_poll_wait(events, timeout) \
	compat_poll_wait(events, timeout)

/*
 * 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)

/*
 * 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);
	}
}

#endif /* HAVE_EPOLL */

#endif /* _LTT_POLL_H */
Commit	Line	Data
	1	/*
	2	* Copyright (C) 2011 - David Goulet <david.goulet@polymtl.ca>
	3	*
	4	* This program is free software; you can redistribute it and/or modify
	5	* it under the terms of the GNU General Public License, version 2 only,
	6	* as published by the Free Software Foundation.
	7	*
	8	* This program is distributed in the hope that it will be useful, but WITHOUT
	9	* ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
	10	* FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for
	11	* more details.
	12	*
	13	* You should have received a copy of the GNU General Public License along
	14	* with this program; if not, write to the Free Software Foundation, Inc.,
	15	* 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
	16	*/
	17
	18	#ifndef _LTT_POLL_H
	19	#define _LTT_POLL_H
	20
	21	#include <assert.h>
	22	#include <string.h>
	23	#include <unistd.h>
	24
	25	#include <common/common.h>
	26
	27	/*
	28	* Maximum number of fd we can monitor.
	29	*
	30	* For epoll(7), /proc/sys/fs/epoll/max_user_watches (since Linux 2.6.28) will
	31	* be used for the maximum size of the poll set. If this interface is not
	32	* available, according to the manpage, the max_user_watches value is 1/25 (4%)
	33	* of the available low memory divided by the registration cost in bytes which
	34	* is 90 bytes on a 32-bit kernel and 160 bytes on a 64-bit kernel.
	35	*
	36	* For poll(2), the max fds must not exceed RLIMIT_NOFILE given by
	37	* getrlimit(2).
	38	*/
	39	extern unsigned int poll_max_size;
	40
	41	/*
	42	* Used by lttng_poll_clean to free the events structure in a lttng_poll_event.
	43	*/
	44	static inline void __lttng_poll_free(void *events)
	45	{
	46	free(events);
	47	}
	48
	49	/*
	50	* epoll(7) implementation.
	51	*/
	52	#ifdef HAVE_EPOLL
	53	#include <sys/epoll.h>
	54	#include <stdio.h>
	55	#include <features.h>
	56	#include <common/compat/fcntl.h>
	57
	58	/* See man epoll(7) for this define path */
	59	#define COMPAT_EPOLL_PROC_PATH "/proc/sys/fs/epoll/max_user_watches"
	60
	61	enum {
	62	/* Polling variables compatibility for epoll */
	63	LPOLLIN = EPOLLIN,
	64	LPOLLPRI = EPOLLPRI,
	65	LPOLLOUT = EPOLLOUT,
	66	LPOLLRDNORM = EPOLLRDNORM,
	67	LPOLLRDBAND = EPOLLRDBAND,
	68	LPOLLWRNORM = EPOLLWRNORM,
	69	LPOLLWRBAND = EPOLLWRBAND,
	70	LPOLLMSG = EPOLLMSG,
	71	LPOLLERR = EPOLLERR,
	72	LPOLLHUP = EPOLLHUP,
	73	LPOLLNVAL = EPOLLHUP,
	74	LPOLLRDHUP = EPOLLRDHUP,
	75	/* Close on exec feature of epoll */
	76	#if defined(HAVE_EPOLL_CREATE1) && defined(EPOLL_CLOEXEC)
	77	LTTNG_CLOEXEC = EPOLL_CLOEXEC,
	78	#else
	79	/*
	80	* EPOLL_CLOEXEC was added in glibc 2.8 (usually used in conjunction with
	81	* epoll_create1(..)), but since neither EPOLL_CLOEXEC exists nor
	82	* epoll_create1(..), we set it to FD_CLOEXEC so that we can pass it
	83	* directly to fcntl(..) instead.
	84	*/
	85	LTTNG_CLOEXEC = FD_CLOEXEC,
	86	#endif
	87	};
	88
	89	struct compat_epoll_event {
	90	int epfd;
	91	uint32_t nb_fd; /* Current number of fd in events */
	92	uint32_t alloc_size; /* Size of events array */
	93	uint32_t init_size; /* Initial size of events array */
	94	struct epoll_event *events;
	95	};
	96	#define lttng_poll_event compat_epoll_event
	97
	98	static inline int __lttng_epoll_get_prev_fd(struct lttng_poll_event *events,
	99	int index, uint32_t nb_fd)
	100	{
	101	assert(events);
	102	assert(index != nb_fd);
	103
	104	if (index == 0 \|\| nb_fd == 0) {
	105	return -1;
	106	} else {
	107	return events->events[index - 1].data.fd;
	108	}
	109	}
	110
	111	/*
	112	* For the following calls, consider 'e' to be a lttng_poll_event pointer and i
	113	* being the index of the events array.
	114	*/
	115	#define LTTNG_POLL_GETFD(e, i) LTTNG_REF(e)->events[i].data.fd
	116	#define LTTNG_POLL_GETEV(e, i) LTTNG_REF(e)->events[i].events
	117	#define LTTNG_POLL_GETNB(e) LTTNG_REF(e)->nb_fd
	118	#define LTTNG_POLL_GETSZ(e) LTTNG_REF(e)->events_size
	119	#define LTTNG_POLL_GET_PREV_FD(e, i, nb_fd) \
	120	__lttng_epoll_get_prev_fd(LTTNG_REF(e), i, nb_fd)
	121
	122	/*
	123	* Create the epoll set. No memory allocation is done here.
	124	*/
	125	extern int compat_epoll_create(struct lttng_poll_event *events,
	126	int size, int flags);
	127	#define lttng_poll_create(events, size, flags) \
	128	compat_epoll_create(events, size, flags)
	129
	130	#if defined(HAVE_EPOLL_CREATE1) && defined(EPOLL_CLOEXEC)
	131	static inline int compat_glibc_epoll_create(int size __attribute__((unused)),
	132	int flags)
	133	{
	134	return epoll_create1(flags);
	135	}
	136	#else
	137	static inline int compat_glibc_epoll_create(int size, int flags)
	138	{
	139	/*
	140	* epoll_create1 was added in glibc 2.9, but unfortunatly reverting to
	141	* epoll_create(..) also means that we lose the possibility to
	142	* directly set the EPOLL_CLOEXEC, so try and do it anyway but through
	143	* fcntl(..).
	144	*/
	145	int efd = epoll_create(size);
	146	assert(fcntl(efd, F_SETFD, flags) != -1);
	147	return efd;
	148	}
	149	#endif
	150
	151	/*
	152	* Wait on epoll set with the number of fd registered to the lttng_poll_event
	153	* data structure (events).
	154	*/
	155	extern int compat_epoll_wait(struct lttng_poll_event *events, int timeout);
	156	#define lttng_poll_wait(events, timeout) \
	157	compat_epoll_wait(events, timeout)
	158
	159	/*
	160	* Add a fd to the epoll set and resize the epoll_event structure if needed.
	161	*/
	162	extern int compat_epoll_add(struct lttng_poll_event *events,
	163	int fd, uint32_t req_events);
	164	#define lttng_poll_add(events, fd, req_events) \
	165	compat_epoll_add(events, fd, req_events)
	166
	167	/*
	168	* Remove a fd from the epoll set.
	169	*/
	170	extern int compat_epoll_del(struct lttng_poll_event *events, int fd);
	171	#define lttng_poll_del(events, fd) \
	172	compat_epoll_del(events, fd)
	173
	174	/*
	175	* Set up the poll set limits variable poll_max_size
	176	*/
	177	extern int compat_epoll_set_max_size(void);
	178	#define lttng_poll_set_max_size() \
	179	compat_epoll_set_max_size()
	180
	181	/*
	182	* This function memset with zero the structure since it can be reused at each
	183	* round of a main loop. Being in a loop and using a non static number of fds,
	184	* this function must be called to insure coherent events with associted fds.
	185	*/
	186	static inline void lttng_poll_reset(struct lttng_poll_event *events)
	187	{
	188	if (events && events->events) {
	189	memset(events->events, 0,
	190	events->nb_fd * sizeof(struct epoll_event));
	191	}
	192	}
	193
	194	/*
	195	* Initialize an already allocated poll event data structure. For epoll(), the
	196	* epfd is set to -1 to indicate that it's not usable.
	197	*/
	198	static inline void lttng_poll_init(struct lttng_poll_event *events)
	199	{
	200	memset(events, 0, sizeof(struct lttng_poll_event));
	201	/* Set fd to -1 so if clean before created, we don't close 0. */
	202	events->epfd = -1;
	203	}
	204
	205	/*
	206	* Clean the events structure of a lttng_poll_event. It's the caller
	207	* responsability to free the lttng_poll_event memory.
	208	*/
	209	static inline void lttng_poll_clean(struct lttng_poll_event *events)
	210	{
	211	int ret;
	212
	213	if (!events) {
	214	return;
	215	}
	216
	217	if (events->epfd >= 0) {
	218	ret = close(events->epfd);
	219	if (ret) {
	220	PERROR("close");
	221	}
	222	}
	223
	224	__lttng_poll_free((void *) events->events);
	225	}
	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	enum {
	246	/* Polling variables compatibility for poll */
	247	LPOLLIN = POLLIN,
	248	LPOLLPRI = POLLPRI,
	249	LPOLLOUT = POLLOUT,
	250	LPOLLRDNORM = POLLRDNORM,
	251	LPOLLRDBAND = POLLRDBAND,
	252	LPOLLWRNORM = POLLWRNORM,
	253	LPOLLWRBAND = POLLWRBAND,
	254	#if __linux__
	255	LPOLLMSG = POLLMSG,
	256	LPOLLRDHUP = POLLRDHUP,
	257	#elif (defined(__FreeBSD__) \|\| defined(__CYGWIN__) \|\| defined(__sun__))
	258	LPOLLMSG = 0,
	259	LPOLLRDHUP = 0,
	260	#else
	261	#error "Please add support for your OS."
	262	#endif /* __linux__ */
	263	LPOLLERR = POLLERR,
	264	LPOLLHUP = POLLHUP \| POLLNVAL,
	265	/* Close on exec feature does not exist for poll(2) */
	266	LTTNG_CLOEXEC = 0xdead,
	267	};
	268
	269	struct compat_poll_event_array {
	270	uint32_t nb_fd; /* Current number of fd in events */
	271	uint32_t alloc_size; /* Size of events array */
	272	/* Initial size of the pollset. We never shrink below that. */
	273	uint32_t init_size;
	274	struct pollfd *events;
	275	};
	276
	277	struct compat_poll_event {
	278	/*
	279	* Modified by the wait action. Updated using current fields if the
	280	* need_update flag is set.
	281	*/
	282	struct compat_poll_event_array wait;
	283	/*
	284	* This is modified by add/del actions being the _current_ flow of
	285	* execution before a poll wait is done.
	286	*/
	287	struct compat_poll_event_array current;
	288
	289	/* Indicate if wait.events need to be updated from current. */
	290	int need_update:1;
	291	};
	292	#define lttng_poll_event compat_poll_event
	293
	294	static inline int __lttng_poll_get_prev_fd(struct lttng_poll_event *events,
	295	int index, uint32_t nb_fd)
	296	{
	297	assert(events);
	298	assert(index != nb_fd);
	299
	300	if (index == 0 \|\| nb_fd == 0) {
	301	return -1;
	302	} else {
	303	return events->current.events[index - 1].fd;
	304	}
	305	}
	306
	307	/*
	308	* For the following calls, consider 'e' to be a lttng_poll_event pointer and i
	309	* being the index of the events array.
	310	*/
	311	#define LTTNG_POLL_GETFD(e, i) LTTNG_REF(e)->wait.events[i].fd
	312	#define LTTNG_POLL_GETEV(e, i) LTTNG_REF(e)->wait.events[i].revents
	313	#define LTTNG_POLL_GETNB(e) LTTNG_REF(e)->wait.nb_fd
	314	#define LTTNG_POLL_GETSZ(e) LTTNG_REF(e)->wait.events_size
	315	#define LTTNG_POLL_GET_PREV_FD(e, i, nb_fd) \
	316	__lttng_poll_get_prev_fd(LTTNG_REF(e), i, nb_fd)
	317
	318	/*
	319	* Create a pollfd structure of size 'size'.
	320	*/
	321	extern int compat_poll_create(struct lttng_poll_event *events, int size);
	322	#define lttng_poll_create(events, size, flags) \
	323	compat_poll_create(events, size)
	324
	325	/*
	326	* Wait on poll(2) event with nb_fd registered to the lttng_poll_event data
	327	* structure.
	328	*/
	329	extern int compat_poll_wait(struct lttng_poll_event *events, int timeout);
	330	#define lttng_poll_wait(events, timeout) \
	331	compat_poll_wait(events, timeout)
	332
	333	/*
	334	* Add the fd to the pollfd structure. Resize if needed.
	335	*/
	336	extern int compat_poll_add(struct lttng_poll_event *events,
	337	int fd, uint32_t req_events);
	338	#define lttng_poll_add(events, fd, req_events) \
	339	compat_poll_add(events, fd, req_events)
	340
	341	/*
	342	* Remove the fd from the pollfd. Memory allocation is done to recreate a new
	343	* pollfd, data is copied from the old pollfd to the new and, finally, the old
	344	* one is freed().
	345	*/
	346	extern int compat_poll_del(struct lttng_poll_event *events, int fd);
	347	#define lttng_poll_del(events, fd) \
	348	compat_poll_del(events, fd)
	349
	350	/*
	351	* Set up the poll set limits variable poll_max_size
	352	*/
	353	extern int compat_poll_set_max_size(void);
	354	#define lttng_poll_set_max_size() \
	355	compat_poll_set_max_size()
	356
	357	/*
	358	* No need to reset a pollfd structure for poll(2)
	359	*/
	360	static inline void lttng_poll_reset(struct lttng_poll_event *events)
	361	{}
	362
	363	/*
	364	* Initialize an already allocated poll event data structure.
	365	*/
	366	static inline void lttng_poll_init(struct lttng_poll_event *events)
	367	{
	368	memset(events, 0, sizeof(struct lttng_poll_event));
	369	}
	370
	371	/*
	372	* Clean the events structure of a lttng_poll_event. It's the caller
	373	* responsability to free the lttng_poll_event memory.
	374	*/
	375	static inline void lttng_poll_clean(struct lttng_poll_event *events)
	376	{
	377	if (events) {
	378	__lttng_poll_free((void *) events->wait.events);
	379	__lttng_poll_free((void *) events->current.events);
	380	}
	381	}
	382
	383	#endif /* HAVE_EPOLL */
	384
	385	#endif /* _LTT_POLL_H */