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

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

#ifndef _LTT_POLL_H
#define _LTT_POLL_H

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

#include <common/common.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 <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. */
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,
		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);
}

#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__) || 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)
{
	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.
 * 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);
	}
}

#endif /* HAVE_EPOLL */

#endif /* _LTT_POLL_H */
Commit	Line	Data
5eb91c98	1	/*
90c106c6	2	* Copyright (C) 2011 EfficiOS Inc.
5eb91c98	3	*
395004a1	4	* SPDX-License-Identifier: LGPL-2.1-only
5eb91c98	5	*
5eb91c98 DG	6	*/
	7
	8	#ifndef _LTT_POLL_H
	9	#define _LTT_POLL_H
	10
beaad64c	11	#include <assert.h>
5eb91c98 DG	12	#include <string.h>
	13	#include <unistd.h>
	14
990570ed	15	#include <common/common.h>
5eb91c98	16
5eb91c98 DG	17	/*
	18	* Used by lttng_poll_clean to free the events structure in a lttng_poll_event.
	19	*/
	20	static inline void __lttng_poll_free(void *events)
	21	{
0e428499	22	free(events);
5eb91c98 DG	23	}
	24
	25	/*
	26	* epoll(7) implementation.
	27	*/
	28	#ifdef HAVE_EPOLL
	29	#include <sys/epoll.h>
76d7553f	30	#include <stdio.h>
f263b7fd JD	31	#include <features.h>
f263b7fd JD	32	#include <common/compat/fcntl.h>
5eb91c98 DG	33
5eb91c98 DG	34	/* See man epoll(7) for this define path */
990570ed	35	#define COMPAT_EPOLL_PROC_PATH "/proc/sys/fs/epoll/max_user_watches"
5eb91c98 DG	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 */
062fc3d8	52	#if defined(HAVE_EPOLL_CREATE1) && defined(EPOLL_CLOEXEC)
5eb91c98	53	LTTNG_CLOEXEC = EPOLL_CLOEXEC,
f263b7fd JD	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
5eb91c98 DG	63	};
	64
	65	struct compat_epoll_event {
	66	int epfd;
	67	uint32_t nb_fd; /* Current number of fd in events */
d21b0d71 DG	68	uint32_t alloc_size; /* Size of events array */
d21b0d71 DG	69	uint32_t init_size; /* Initial size of events array */
5eb91c98 DG	70	struct epoll_event *events;
	71	};
	72	#define lttng_poll_event compat_epoll_event
	73
beaad64c DG	74	static inline int __lttng_epoll_get_prev_fd(struct lttng_poll_event *events,
	75	int index, uint32_t nb_fd)
	76	{
	77	assert(events);
	78	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
5eb91c98 DG	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
beaad64c DG	95	#define LTTNG_POLL_GET_PREV_FD(e, i, nb_fd) \
beaad64c DG	96	__lttng_epoll_get_prev_fd(LTTNG_REF(e), i, nb_fd)
5eb91c98	97
5a12931e	98	/* Create the epoll set. */
5eb91c98 DG	99	extern int compat_epoll_create(struct lttng_poll_event *events,
	100	int size, int flags);
	101	#define lttng_poll_create(events, size, flags) \
65b1b198	102	compat_epoll_create(events, size, flags)
5eb91c98	103
062fc3d8	104	#if defined(HAVE_EPOLL_CREATE1) && defined(EPOLL_CLOEXEC)
f263b7fd JD	105	static inline int compat_glibc_epoll_create(int size __attribute__((unused)),
	106	int flags)
	107	{
	108	return epoll_create1(flags);
	109	}
	110	#else
	111	static inline int compat_glibc_epoll_create(int size, int flags)
	112	{
	113	/*
	114	* epoll_create1 was added in glibc 2.9, but unfortunatly reverting to
	115	* epoll_create(..) also means that we lose the possibility to
	116	* directly set the EPOLL_CLOEXEC, so try and do it anyway but through
	117	* fcntl(..).
	118	*/
	119	int efd = epoll_create(size);
	120	assert(fcntl(efd, F_SETFD, flags) != -1);
	121	return efd;
	122	}
	123	#endif
	124
5eb91c98 DG	125	/*
	126	* Wait on epoll set with the number of fd registered to the lttng_poll_event
	127	* data structure (events).
	128	*/
9f32e9bf MD	129	extern int compat_epoll_wait(struct lttng_poll_event *events, int timeout,
9f32e9bf MD	130	bool interruptible);
5eb91c98	131	#define lttng_poll_wait(events, timeout) \
9f32e9bf MD	132	compat_epoll_wait(events, timeout, false)
	133	#define lttng_poll_wait_interruptible(events, timeout) \
	134	compat_epoll_wait(events, timeout, true)
5eb91c98 DG	135
	136	/*
	137	* Add a fd to the epoll set and resize the epoll_event structure if needed.
	138	*/
	139	extern int compat_epoll_add(struct lttng_poll_event *events,
	140	int fd, uint32_t req_events);
	141	#define lttng_poll_add(events, fd, req_events) \
65b1b198	142	compat_epoll_add(events, fd, req_events)
5eb91c98 DG	143
	144	/*
	145	* Remove a fd from the epoll set.
	146	*/
	147	extern int compat_epoll_del(struct lttng_poll_event *events, int fd);
	148	#define lttng_poll_del(events, fd) \
65b1b198	149	compat_epoll_del(events, fd)
5eb91c98	150
f057dfc3 JG	151	/*
	152	* Modify an fd's events in the epoll set.
	153	*/
	154	extern int compat_epoll_mod(struct lttng_poll_event *events,
	155	int fd, uint32_t req_events);
	156	#define lttng_poll_mod(events, fd, req_events) \
2a85be8e	157	compat_epoll_mod(events, fd, req_events)
f057dfc3	158
5eb91c98 DG	159	/*
	160	* Set up the poll set limits variable poll_max_size
	161	*/
dbe23f45	162	extern int compat_epoll_set_max_size(void);
65b1b198 MD	163	#define lttng_poll_set_max_size() \
65b1b198 MD	164	compat_epoll_set_max_size()
5eb91c98 DG	165
	166	/*
	167	* This function memset with zero the structure since it can be reused at each
	168	* round of a main loop. Being in a loop and using a non static number of fds,
	169	* this function must be called to insure coherent events with associted fds.
	170	*/
	171	static inline void lttng_poll_reset(struct lttng_poll_event *events)
	172	{
	173	if (events && events->events) {
	174	memset(events->events, 0,
	175	events->nb_fd * sizeof(struct epoll_event));
	176	}
	177	}
	178
6d737ce4 DG	179	/*
	180	* Initialize an already allocated poll event data structure. For epoll(), the
	181	* epfd is set to -1 to indicate that it's not usable.
	182	*/
	183	static inline void lttng_poll_init(struct lttng_poll_event *events)
	184	{
c5854b1c	185	memset(events, 0, sizeof(struct lttng_poll_event));
6d737ce4 DG	186	/* Set fd to -1 so if clean before created, we don't close 0. */
	187	events->epfd = -1;
	188	}
	189
5eb91c98 DG	190	/*
	191	* Clean the events structure of a lttng_poll_event. It's the caller
	192	* responsability to free the lttng_poll_event memory.
	193	*/
	194	static inline void lttng_poll_clean(struct lttng_poll_event *events)
	195	{
76d7553f MD	196	int ret;
76d7553f MD	197
3cc04881 DG	198	if (!events) {
	199	return;
	200	}
	201
	202	if (events->epfd >= 0) {
76d7553f MD	203	ret = close(events->epfd);
76d7553f MD	204	if (ret) {
6f04ed72	205	PERROR("close");
76d7553f	206	}
5eb91c98	207	}
3cc04881 DG	208
3cc04881 DG	209	__lttng_poll_free((void *) events->events);
5eb91c98 DG	210	}
	211
	212	#else /* HAVE_EPOLL */
	213	/*
	214	* Fallback on poll(2) API
	215	*/
	216
	217	/* Needed for some poll event values */
	218	#ifndef __USE_XOPEN
	219	#define __USE_XOPEN
	220	#endif
	221
	222	/* Needed for some poll event values */
	223	#ifndef __USE_GNU
	224	#define __USE_GNU
	225	#endif
	226
	227	#include <poll.h>
	228	#include <stdint.h>
	229
	230	enum {
	231	/* Polling variables compatibility for poll */
	232	LPOLLIN = POLLIN,
	233	LPOLLPRI = POLLPRI,
	234	LPOLLOUT = POLLOUT,
	235	LPOLLRDNORM = POLLRDNORM,
	236	LPOLLRDBAND = POLLRDBAND,
	237	LPOLLWRNORM = POLLWRNORM,
	238	LPOLLWRBAND = POLLWRBAND,
1268b9d6	239	#if __linux__
5eb91c98	240	LPOLLMSG = POLLMSG,
1268b9d6	241	LPOLLRDHUP = POLLRDHUP,
a97dd6ce	242	#elif (defined(__FreeBSD__) \|\| defined(__CYGWIN__) \|\| defined(__sun__) \|\| defined(__APPLE__))
1268b9d6 DG	243	LPOLLMSG = 0,
1268b9d6 DG	244	LPOLLRDHUP = 0,
b2c3836f MD	245	#else
b2c3836f MD	246	#error "Please add support for your OS."
1268b9d6	247	#endif /* __linux__ */
5eb91c98 DG	248	LPOLLERR = POLLERR,
5eb91c98 DG	249	LPOLLHUP = POLLHUP \| POLLNVAL,
5eb91c98 DG	250	/* Close on exec feature does not exist for poll(2) */
	251	LTTNG_CLOEXEC = 0xdead,
	252	};
	253
d21b0d71	254	struct compat_poll_event_array {
5eb91c98	255	uint32_t nb_fd; /* Current number of fd in events */
d21b0d71 DG	256	uint32_t alloc_size; /* Size of events array */
	257	/* Initial size of the pollset. We never shrink below that. */
	258	uint32_t init_size;
5eb91c98 DG	259	struct pollfd *events;
5eb91c98 DG	260	};
d21b0d71 DG	261
	262	struct compat_poll_event {
	263	/*
	264	* Modified by the wait action. Updated using current fields if the
	265	* need_update flag is set.
	266	*/
	267	struct compat_poll_event_array wait;
	268	/*
	269	* This is modified by add/del actions being the _current_ flow of
	270	* execution before a poll wait is done.
	271	*/
	272	struct compat_poll_event_array current;
dbe23f45	273
d21b0d71 DG	274	/* Indicate if wait.events need to be updated from current. */
	275	int need_update:1;
	276	};
5eb91c98 DG	277	#define lttng_poll_event compat_poll_event
5eb91c98 DG	278
beaad64c DG	279	static inline int __lttng_poll_get_prev_fd(struct lttng_poll_event *events,
	280	int index, uint32_t nb_fd)
	281	{
	282	assert(events);
	283	assert(index != nb_fd);
	284
	285	if (index == 0 \|\| nb_fd == 0) {
	286	return -1;
	287	} else {
	288	return events->current.events[index - 1].fd;
	289	}
	290	}
	291
5eb91c98 DG	292	/*
	293	* For the following calls, consider 'e' to be a lttng_poll_event pointer and i
	294	* being the index of the events array.
7e222fa8 YL	295	* LTTNG_POLL_GETNB is always used after lttng_poll_wait, thus we can use the
7e222fa8 YL	296	* current list for test compatibility purposes.
5eb91c98	297	*/
d21b0d71 DG	298	#define LTTNG_POLL_GETFD(e, i) LTTNG_REF(e)->wait.events[i].fd
d21b0d71 DG	299	#define LTTNG_POLL_GETEV(e, i) LTTNG_REF(e)->wait.events[i].revents
7e222fa8	300	#define LTTNG_POLL_GETNB(e) LTTNG_REF(e)->current.nb_fd
d21b0d71	301	#define LTTNG_POLL_GETSZ(e) LTTNG_REF(e)->wait.events_size
beaad64c DG	302	#define LTTNG_POLL_GET_PREV_FD(e, i, nb_fd) \
beaad64c DG	303	__lttng_poll_get_prev_fd(LTTNG_REF(e), i, nb_fd)
5eb91c98 DG	304
	305	/*
	306	* Create a pollfd structure of size 'size'.
	307	*/
	308	extern int compat_poll_create(struct lttng_poll_event *events, int size);
	309	#define lttng_poll_create(events, size, flags) \
65b1b198	310	compat_poll_create(events, size)
5eb91c98 DG	311
	312	/*
	313	* Wait on poll(2) event with nb_fd registered to the lttng_poll_event data
	314	* structure.
	315	*/
9f32e9bf MD	316	extern int compat_poll_wait(struct lttng_poll_event *events, int timeout,
9f32e9bf MD	317	bool interruptible);
5eb91c98	318	#define lttng_poll_wait(events, timeout) \
9f32e9bf MD	319	compat_poll_wait(events, timeout, false)
	320	#define lttng_poll_wait_interruptible(events, timeout) \
	321	compat_poll_wait(events, timeout, true)
5eb91c98 DG	322
	323	/*
	324	* Add the fd to the pollfd structure. Resize if needed.
	325	*/
	326	extern int compat_poll_add(struct lttng_poll_event *events,
	327	int fd, uint32_t req_events);
	328	#define lttng_poll_add(events, fd, req_events) \
65b1b198	329	compat_poll_add(events, fd, req_events)
5eb91c98 DG	330
	331	/*
	332	* Remove the fd from the pollfd. Memory allocation is done to recreate a new
	333	* pollfd, data is copied from the old pollfd to the new and, finally, the old
	334	* one is freed().
	335	*/
	336	extern int compat_poll_del(struct lttng_poll_event *events, int fd);
	337	#define lttng_poll_del(events, fd) \
65b1b198	338	compat_poll_del(events, fd)
5eb91c98	339
f057dfc3	340	/*
b14f53d4	341	* Modify an fd's events in the poll set.
f057dfc3 JG	342	*/
	343	extern int compat_poll_mod(struct lttng_poll_event *events,
	344	int fd, uint32_t req_events);
	345	#define lttng_poll_mod(events, fd, req_events) \
2a85be8e	346	compat_poll_mod(events, fd, req_events)
f057dfc3	347
5eb91c98 DG	348	/*
	349	* Set up the poll set limits variable poll_max_size
	350	*/
dbe23f45	351	extern int compat_poll_set_max_size(void);
65b1b198 MD	352	#define lttng_poll_set_max_size() \
65b1b198 MD	353	compat_poll_set_max_size()
5eb91c98 DG	354
	355	/*
	356	* No need to reset a pollfd structure for poll(2)
	357	*/
	358	static inline void lttng_poll_reset(struct lttng_poll_event *events)
	359	{}
	360
6d737ce4 DG	361	/*
	362	* Initialize an already allocated poll event data structure.
	363	*/
	364	static inline void lttng_poll_init(struct lttng_poll_event *events)
	365	{
	366	memset(events, 0, sizeof(struct lttng_poll_event));
	367	}
	368
5eb91c98 DG	369	/*
	370	* Clean the events structure of a lttng_poll_event. It's the caller
	371	* responsability to free the lttng_poll_event memory.
	372	*/
	373	static inline void lttng_poll_clean(struct lttng_poll_event *events)
	374	{
	375	if (events) {
d21b0d71 DG	376	__lttng_poll_free((void *) events->wait.events);
d21b0d71 DG	377	__lttng_poll_free((void *) events->current.events);
5eb91c98 DG	378	}
	379	}
	380
	381	#endif /* HAVE_EPOLL */
	382
	383	#endif /* _LTT_POLL_H */