[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>

/*
 * 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)
{
	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);
}

#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)
{
	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);
	}
}

#endif /* HAVE_EPOLL */

#endif /* _LTT_POLL_H */
Commit	Line	Data
5eb91c98	1	/*
ab5be9fa	2	* Copyright (C) 2011 David Goulet <david.goulet@polymtl.ca>
5eb91c98	3	*
ab5be9fa	4	* SPDX-License-Identifier: GPL-2.0-only
5eb91c98	5	*
5eb91c98 DG	6	*/
	7
	8	#ifndef _LTT_POLL_H
	9	#define _LTT_POLL_H
	10
	11	#include <string.h>
	12	#include <unistd.h>
	13
990570ed	14	#include <common/common.h>
5eb91c98	15
5eb91c98 DG	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	{
0e428499	21	free(events);
5eb91c98 DG	22	}
	23
	24	/*
	25	* epoll(7) implementation.
	26	*/
	27	#ifdef HAVE_EPOLL
	28	#include <sys/epoll.h>
76d7553f	29	#include <stdio.h>
f263b7fd JD	30	#include <features.h>
f263b7fd JD	31	#include <common/compat/fcntl.h>
5eb91c98 DG	32
5eb91c98 DG	33	/* See man epoll(7) for this define path */
990570ed	34	#define COMPAT_EPOLL_PROC_PATH "/proc/sys/fs/epoll/max_user_watches"
5eb91c98 DG	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 */
062fc3d8	51	#if defined(HAVE_EPOLL_CREATE1) && defined(EPOLL_CLOEXEC)
5eb91c98	52	LTTNG_CLOEXEC = EPOLL_CLOEXEC,
f263b7fd JD	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
5eb91c98 DG	62	};
	63
	64	struct compat_epoll_event {
	65	int epfd;
	66	uint32_t nb_fd; /* Current number of fd in events */
d21b0d71 DG	67	uint32_t alloc_size; /* Size of events array */
d21b0d71 DG	68	uint32_t init_size; /* Initial size of events array */
5eb91c98 DG	69	struct epoll_event *events;
	70	};
	71	#define lttng_poll_event compat_epoll_event
	72
beaad64c DG	73	static inline int __lttng_epoll_get_prev_fd(struct lttng_poll_event *events,
	74	int index, uint32_t nb_fd)
	75	{
a0377dfe FD	76	LTTNG_ASSERT(events);
a0377dfe FD	77	LTTNG_ASSERT(index != nb_fd);
beaad64c DG	78
	79	if (index == 0 \|\| nb_fd == 0) {
	80	return -1;
	81	} else {
	82	return events->events[index - 1].data.fd;
	83	}
	84	}
	85
5eb91c98 DG	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
beaad64c DG	94	#define LTTNG_POLL_GET_PREV_FD(e, i, nb_fd) \
beaad64c DG	95	__lttng_epoll_get_prev_fd(LTTNG_REF(e), i, nb_fd)
5eb91c98	96
5a12931e	97	/* Create the epoll set. */
5eb91c98 DG	98	extern int compat_epoll_create(struct lttng_poll_event *events,
	99	int size, int flags);
	100	#define lttng_poll_create(events, size, flags) \
65b1b198	101	compat_epoll_create(events, size, flags)
5eb91c98	102
062fc3d8	103	#if defined(HAVE_EPOLL_CREATE1) && defined(EPOLL_CLOEXEC)
f263b7fd JD	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);
a0377dfe	119	LTTNG_ASSERT(fcntl(efd, F_SETFD, flags) != -1);
f263b7fd JD	120	return efd;
	121	}
	122	#endif
	123
5eb91c98 DG	124	/*
	125	* Wait on epoll set with the number of fd registered to the lttng_poll_event
	126	* data structure (events).
	127	*/
9f32e9bf MD	128	extern int compat_epoll_wait(struct lttng_poll_event *events, int timeout,
9f32e9bf MD	129	bool interruptible);
5eb91c98	130	#define lttng_poll_wait(events, timeout) \
9f32e9bf MD	131	compat_epoll_wait(events, timeout, false)
	132	#define lttng_poll_wait_interruptible(events, timeout) \
	133	compat_epoll_wait(events, timeout, true)
5eb91c98 DG	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) \
65b1b198	141	compat_epoll_add(events, fd, req_events)
5eb91c98 DG	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) \
65b1b198	148	compat_epoll_del(events, fd)
5eb91c98	149
f057dfc3 JG	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) \
2a85be8e	156	compat_epoll_mod(events, fd, req_events)
f057dfc3	157
5eb91c98 DG	158	/*
	159	* Set up the poll set limits variable poll_max_size
	160	*/
dbe23f45	161	extern int compat_epoll_set_max_size(void);
65b1b198 MD	162	#define lttng_poll_set_max_size() \
65b1b198 MD	163	compat_epoll_set_max_size()
5eb91c98 DG	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
6d737ce4 DG	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	{
c5854b1c	184	memset(events, 0, sizeof(struct lttng_poll_event));
6d737ce4 DG	185	/* Set fd to -1 so if clean before created, we don't close 0. */
	186	events->epfd = -1;
	187	}
	188
5eb91c98 DG	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	{
76d7553f MD	195	int ret;
76d7553f MD	196
3cc04881 DG	197	if (!events) {
	198	return;
	199	}
	200
	201	if (events->epfd >= 0) {
76d7553f MD	202	ret = close(events->epfd);
76d7553f MD	203	if (ret) {
6f04ed72	204	PERROR("close");
76d7553f	205	}
5eb91c98	206	}
3cc04881 DG	207
3cc04881 DG	208	__lttng_poll_free((void *) events->events);
5eb91c98 DG	209	}
	210
	211	#else /* HAVE_EPOLL */
	212	/*
	213	* Fallback on poll(2) API
	214	*/
	215
	216	/* Needed for some poll event values */
	217	#ifndef __USE_XOPEN
	218	#define __USE_XOPEN
	219	#endif
	220
	221	/* Needed for some poll event values */
	222	#ifndef __USE_GNU
	223	#define __USE_GNU
	224	#endif
	225
	226	#include <poll.h>
	227	#include <stdint.h>
	228
	229	enum {
	230	/* Polling variables compatibility for poll */
	231	LPOLLIN = POLLIN,
	232	LPOLLPRI = POLLPRI,
	233	LPOLLOUT = POLLOUT,
	234	LPOLLRDNORM = POLLRDNORM,
	235	LPOLLRDBAND = POLLRDBAND,
	236	LPOLLWRNORM = POLLWRNORM,
	237	LPOLLWRBAND = POLLWRBAND,
1268b9d6	238	#if __linux__
5eb91c98	239	LPOLLMSG = POLLMSG,
1268b9d6	240	LPOLLRDHUP = POLLRDHUP,
a97dd6ce	241	#elif (defined(__FreeBSD__) \|\| defined(__CYGWIN__) \|\| defined(__sun__) \|\| defined(__APPLE__))
1268b9d6 DG	242	LPOLLMSG = 0,
1268b9d6 DG	243	LPOLLRDHUP = 0,
b2c3836f MD	244	#else
b2c3836f MD	245	#error "Please add support for your OS."
1268b9d6	246	#endif /* __linux__ */
5eb91c98 DG	247	LPOLLERR = POLLERR,
5eb91c98 DG	248	LPOLLHUP = POLLHUP \| POLLNVAL,
5eb91c98 DG	249	/* Close on exec feature does not exist for poll(2) */
	250	LTTNG_CLOEXEC = 0xdead,
	251	};
	252
d21b0d71	253	struct compat_poll_event_array {
5eb91c98	254	uint32_t nb_fd; /* Current number of fd in events */
d21b0d71 DG	255	uint32_t alloc_size; /* Size of events array */
	256	/* Initial size of the pollset. We never shrink below that. */
	257	uint32_t init_size;
5eb91c98 DG	258	struct pollfd *events;
5eb91c98 DG	259	};
d21b0d71 DG	260
	261	struct compat_poll_event {
	262	/*
	263	* Modified by the wait action. Updated using current fields if the
	264	* need_update flag is set.
	265	*/
	266	struct compat_poll_event_array wait;
	267	/*
	268	* This is modified by add/del actions being the _current_ flow of
	269	* execution before a poll wait is done.
	270	*/
	271	struct compat_poll_event_array current;
dbe23f45	272
d21b0d71 DG	273	/* Indicate if wait.events need to be updated from current. */
	274	int need_update:1;
	275	};
5eb91c98 DG	276	#define lttng_poll_event compat_poll_event
5eb91c98 DG	277
beaad64c DG	278	static inline int __lttng_poll_get_prev_fd(struct lttng_poll_event *events,
	279	int index, uint32_t nb_fd)
	280	{
a0377dfe FD	281	LTTNG_ASSERT(events);
a0377dfe FD	282	LTTNG_ASSERT(index != nb_fd);
beaad64c DG	283
	284	if (index == 0 \|\| nb_fd == 0) {
	285	return -1;
	286	} else {
	287	return events->current.events[index - 1].fd;
	288	}
	289	}
	290
5eb91c98 DG	291	/*
	292	* For the following calls, consider 'e' to be a lttng_poll_event pointer and i
	293	* being the index of the events array.
7e222fa8 YL	294	* LTTNG_POLL_GETNB is always used after lttng_poll_wait, thus we can use the
7e222fa8 YL	295	* current list for test compatibility purposes.
5eb91c98	296	*/
d21b0d71 DG	297	#define LTTNG_POLL_GETFD(e, i) LTTNG_REF(e)->wait.events[i].fd
d21b0d71 DG	298	#define LTTNG_POLL_GETEV(e, i) LTTNG_REF(e)->wait.events[i].revents
7e222fa8	299	#define LTTNG_POLL_GETNB(e) LTTNG_REF(e)->current.nb_fd
d21b0d71	300	#define LTTNG_POLL_GETSZ(e) LTTNG_REF(e)->wait.events_size
beaad64c DG	301	#define LTTNG_POLL_GET_PREV_FD(e, i, nb_fd) \
beaad64c DG	302	__lttng_poll_get_prev_fd(LTTNG_REF(e), i, nb_fd)
5eb91c98 DG	303
	304	/*
	305	* Create a pollfd structure of size 'size'.
	306	*/
	307	extern int compat_poll_create(struct lttng_poll_event *events, int size);
	308	#define lttng_poll_create(events, size, flags) \
65b1b198	309	compat_poll_create(events, size)
5eb91c98 DG	310
	311	/*
	312	* Wait on poll(2) event with nb_fd registered to the lttng_poll_event data
	313	* structure.
	314	*/
9f32e9bf MD	315	extern int compat_poll_wait(struct lttng_poll_event *events, int timeout,
9f32e9bf MD	316	bool interruptible);
5eb91c98	317	#define lttng_poll_wait(events, timeout) \
9f32e9bf MD	318	compat_poll_wait(events, timeout, false)
	319	#define lttng_poll_wait_interruptible(events, timeout) \
	320	compat_poll_wait(events, timeout, true)
5eb91c98 DG	321
	322	/*
	323	* Add the fd to the pollfd structure. Resize if needed.
	324	*/
	325	extern int compat_poll_add(struct lttng_poll_event *events,
	326	int fd, uint32_t req_events);
	327	#define lttng_poll_add(events, fd, req_events) \
65b1b198	328	compat_poll_add(events, fd, req_events)
5eb91c98 DG	329
	330	/*
	331	* Remove the fd from the pollfd. Memory allocation is done to recreate a new
	332	* pollfd, data is copied from the old pollfd to the new and, finally, the old
	333	* one is freed().
	334	*/
	335	extern int compat_poll_del(struct lttng_poll_event *events, int fd);
	336	#define lttng_poll_del(events, fd) \
65b1b198	337	compat_poll_del(events, fd)
5eb91c98	338
f057dfc3	339	/*
b14f53d4	340	* Modify an fd's events in the poll set.
f057dfc3 JG	341	*/
	342	extern int compat_poll_mod(struct lttng_poll_event *events,
	343	int fd, uint32_t req_events);
	344	#define lttng_poll_mod(events, fd, req_events) \
2a85be8e	345	compat_poll_mod(events, fd, req_events)
f057dfc3	346
5eb91c98 DG	347	/*
	348	* Set up the poll set limits variable poll_max_size
	349	*/
dbe23f45	350	extern int compat_poll_set_max_size(void);
65b1b198 MD	351	#define lttng_poll_set_max_size() \
65b1b198 MD	352	compat_poll_set_max_size()
5eb91c98 DG	353
	354	/*
	355	* No need to reset a pollfd structure for poll(2)
	356	*/
	357	static inline void lttng_poll_reset(struct lttng_poll_event *events)
	358	{}
	359
6d737ce4 DG	360	/*
	361	* Initialize an already allocated poll event data structure.
	362	*/
	363	static inline void lttng_poll_init(struct lttng_poll_event *events)
	364	{
	365	memset(events, 0, sizeof(struct lttng_poll_event));
	366	}
	367
5eb91c98 DG	368	/*
	369	* Clean the events structure of a lttng_poll_event. It's the caller
	370	* responsability to free the lttng_poll_event memory.
	371	*/
	372	static inline void lttng_poll_clean(struct lttng_poll_event *events)
	373	{
	374	if (events) {
d21b0d71 DG	375	__lttng_poll_free((void *) events->wait.events);
d21b0d71 DG	376	__lttng_poll_free((void *) events->current.events);
5eb91c98 DG	377	}
	378	}
	379
	380	#endif /* HAVE_EPOLL */
	381
	382	#endif /* _LTT_POLL_H */